Implement GPU Particle Collisions

-Sphere Attractor
-Box Attractor
-Vector Field
-Sphere Collider
-Box Collider
-Baked SDF Collider
-Heightmap Collider

core/math/vector2.h

@@ -65,6 +65,14 @@ struct Vector2 {
 	real_t length() const;
 	real_t length_squared() const;
 
+	Vector2 min(const Vector2 &p_vector2) const {
+		return Vector2(MIN(x, p_vector2.x), MIN(y, p_vector2.y));
+	}
+
+	Vector2 max(const Vector2 &p_vector2) const {
+		return Vector2(MAX(x, p_vector2.x), MAX(y, p_vector2.y));
+	}
+
 	real_t distance_to(const Vector2 &p_vector2) const;
 	real_t distance_squared_to(const Vector2 &p_vector2) const;
 	real_t angle_to(const Vector2 &p_vector2) const;

core/thread_work_pool.h

@@ -73,13 +73,15 @@ class ThreadWorkPool {
 
 	ThreadData *threads = nullptr;
 	uint32_t thread_count = 0;
+	BaseWork *current_work = nullptr;
 
 	static void _thread_function(ThreadData *p_thread);
 
 public:
 	template <class C, class M, class U>
-	void do_work(uint32_t p_elements, C *p_instance, M p_method, U p_userdata) {
+	void begin_work(uint32_t p_elements, C *p_instance, M p_method, U p_userdata) {
 		ERR_FAIL_COND(!threads); //never initialized
+		ERR_FAIL_COND(current_work != nullptr);
 
 		index.store(0);
 
@@ -90,16 +92,37 @@ public:
 		w->index = &index;
 		w->max_elements = p_elements;
 
+		current_work = w;
+
 		for (uint32_t i = 0; i < thread_count; i++) {
 			threads[i].work = w;
 			threads[i].start.post();
 		}
+	}
+
+	bool is_working() const {
+		return current_work != nullptr;
+	}
+
+	uint32_t get_work_index() const {
+		return index;
+	}
+
+	void end_work() {
+		ERR_FAIL_COND(current_work == nullptr);
 		for (uint32_t i = 0; i < thread_count; i++) {
 			threads[i].completed.wait();
 			threads[i].work = nullptr;
 		}
 
-		memdelete(w);
+		memdelete(current_work);
+		current_work = nullptr;
+	}
+
+	template <class C, class M, class U>
+	void do_work(uint32_t p_elements, C *p_instance, M p_method, U p_userdata) {
+		begin_work(p_elements, p_instance, p_method, p_userdata);
+		end_work();
 	}
 
 	void init(int p_thread_count = -1);

editor/editor_node.cpp

@@ -128,6 +128,7 @@
 #include "editor/plugins/gi_probe_editor_plugin.h"
 #include "editor/plugins/gpu_particles_2d_editor_plugin.h"
 #include "editor/plugins/gpu_particles_3d_editor_plugin.h"
+#include "editor/plugins/gpu_particles_collision_sdf_editor_plugin.h"
 #include "editor/plugins/gradient_editor_plugin.h"
 #include "editor/plugins/item_list_editor_plugin.h"
 #include "editor/plugins/light_occluder_2d_editor_plugin.h"
@@ -6635,6 +6636,7 @@ EditorNode::EditorNode() {
 	add_editor_plugin(memnew(PhysicalBone3DEditorPlugin(this)));
 	add_editor_plugin(memnew(MeshEditorPlugin(this)));
 	add_editor_plugin(memnew(MaterialEditorPlugin(this)));
+	add_editor_plugin(memnew(GPUParticlesCollisionSDFEditorPlugin(this)));
 
 	for (int i = 0; i < EditorPlugins::get_plugin_count(); i++) {
 		add_editor_plugin(EditorPlugins::create(i, this));

editor/import/resource_importer_layered_texture.cpp

@@ -51,7 +51,7 @@ String ResourceImporterLayeredTexture::get_importer_name() const {
 			return "cubemap_array_texture";
 		} break;
 		case MODE_3D: {
-			return "cubemap_3d_texture";
+			return "3d_texture";
 		} break;
 	}
 

editor/node_3d_editor_gizmos.cpp

@@ -41,6 +41,7 @@
 #include "scene/3d/decal.h"
 #include "scene/3d/gi_probe.h"
 #include "scene/3d/gpu_particles_3d.h"
+#include "scene/3d/gpu_particles_collision_3d.h"
 #include "scene/3d/light_3d.h"
 #include "scene/3d/lightmap_probe.h"
 #include "scene/3d/listener_3d.h"
@@ -2455,6 +2456,266 @@ void GPUParticles3DGizmoPlugin::redraw(EditorNode3DGizmo *p_gizmo) {
 
 ////
 
+////
+
+GPUParticlesCollision3DGizmoPlugin::GPUParticlesCollision3DGizmoPlugin() {
+	Color gizmo_color = EDITOR_DEF("editors/3d_gizmos/gizmo_colors/particle_collision", Color(0.5, 0.7, 1));
+	create_material("shape_material", gizmo_color);
+	gizmo_color.a = 0.15;
+	create_material("shape_material_internal", gizmo_color);
+
+	create_handle_material("handles");
+}
+
+bool GPUParticlesCollision3DGizmoPlugin::has_gizmo(Node3D *p_spatial) {
+	return (Object::cast_to<GPUParticlesCollision3D>(p_spatial) != nullptr) || (Object::cast_to<GPUParticlesAttractor3D>(p_spatial) != nullptr);
+}
+
+String GPUParticlesCollision3DGizmoPlugin::get_name() const {
+	return "GPUParticlesCollision3D";
+}
+
+int GPUParticlesCollision3DGizmoPlugin::get_priority() const {
+	return -1;
+}
+
+String GPUParticlesCollision3DGizmoPlugin::get_handle_name(const EditorNode3DGizmo *p_gizmo, int p_idx) const {
+	const Node3D *cs = p_gizmo->get_spatial_node();
+
+	if (Object::cast_to<GPUParticlesCollisionSphere>(cs) || Object::cast_to<GPUParticlesAttractorSphere>(cs)) {
+		return "Radius";
+	}
+
+	if (Object::cast_to<GPUParticlesCollisionBox>(cs) || Object::cast_to<GPUParticlesAttractorBox>(cs) || Object::cast_to<GPUParticlesAttractorVectorField>(cs) || Object::cast_to<GPUParticlesCollisionSDF>(cs) || Object::cast_to<GPUParticlesCollisionHeightField>(cs)) {
+		return "Extents";
+	}
+
+	return "";
+}
+
+Variant GPUParticlesCollision3DGizmoPlugin::get_handle_value(EditorNode3DGizmo *p_gizmo, int p_idx) const {
+	const Node3D *cs = p_gizmo->get_spatial_node();
+
+	if (Object::cast_to<GPUParticlesCollisionSphere>(cs) || Object::cast_to<GPUParticlesAttractorSphere>(cs)) {
+		return p_gizmo->get_spatial_node()->call("get_radius");
+	}
+
+	if (Object::cast_to<GPUParticlesCollisionBox>(cs) || Object::cast_to<GPUParticlesAttractorBox>(cs) || Object::cast_to<GPUParticlesAttractorVectorField>(cs) || Object::cast_to<GPUParticlesCollisionSDF>(cs) || Object::cast_to<GPUParticlesCollisionHeightField>(cs)) {
+		return Vector3(p_gizmo->get_spatial_node()->call("get_extents"));
+	}
+
+	return Variant();
+}
+
+void GPUParticlesCollision3DGizmoPlugin::set_handle(EditorNode3DGizmo *p_gizmo, int p_idx, Camera3D *p_camera, const Point2 &p_point) {
+	Node3D *sn = p_gizmo->get_spatial_node();
+
+	Transform gt = sn->get_global_transform();
+	Transform gi = gt.affine_inverse();
+
+	Vector3 ray_from = p_camera->project_ray_origin(p_point);
+	Vector3 ray_dir = p_camera->project_ray_normal(p_point);
+
+	Vector3 sg[2] = { gi.xform(ray_from), gi.xform(ray_from + ray_dir * 4096) };
+
+	if (Object::cast_to<GPUParticlesCollisionSphere>(sn) || Object::cast_to<GPUParticlesAttractorSphere>(sn)) {
+		Vector3 ra, rb;
+		Geometry3D::get_closest_points_between_segments(Vector3(), Vector3(4096, 0, 0), sg[0], sg[1], ra, rb);
+		float d = ra.x;
+		if (Node3DEditor::get_singleton()->is_snap_enabled()) {
+			d = Math::stepify(d, Node3DEditor::get_singleton()->get_translate_snap());
+		}
+
+		if (d < 0.001) {
+			d = 0.001;
+		}
+
+		sn->call("set_radius", d);
+	}
+
+	if (Object::cast_to<GPUParticlesCollisionBox>(sn) || Object::cast_to<GPUParticlesAttractorBox>(sn) || Object::cast_to<GPUParticlesAttractorVectorField>(sn) || Object::cast_to<GPUParticlesCollisionSDF>(sn) || Object::cast_to<GPUParticlesCollisionHeightField>(sn)) {
+		Vector3 axis;
+		axis[p_idx] = 1.0;
+		Vector3 ra, rb;
+		Geometry3D::get_closest_points_between_segments(Vector3(), axis * 4096, sg[0], sg[1], ra, rb);
+		float d = ra[p_idx];
+		if (Node3DEditor::get_singleton()->is_snap_enabled()) {
+			d = Math::stepify(d, Node3DEditor::get_singleton()->get_translate_snap());
+		}
+
+		if (d < 0.001) {
+			d = 0.001;
+		}
+
+		Vector3 he = sn->call("get_extents");
+		he[p_idx] = d;
+		sn->call("set_extents", he);
+	}
+}
+
+void GPUParticlesCollision3DGizmoPlugin::commit_handle(EditorNode3DGizmo *p_gizmo, int p_idx, const Variant &p_restore, bool p_cancel) {
+	Node3D *sn = p_gizmo->get_spatial_node();
+
+	if (Object::cast_to<GPUParticlesCollisionSphere>(sn) || Object::cast_to<GPUParticlesAttractorSphere>(sn)) {
+		if (p_cancel) {
+			sn->call("set_radius", p_restore);
+			return;
+		}
+
+		UndoRedo *ur = Node3DEditor::get_singleton()->get_undo_redo();
+		ur->create_action(TTR("Change Radius"));
+		ur->add_do_method(sn, "set_radius", sn->call("get_radius"));
+		ur->add_undo_method(sn, "set_radius", p_restore);
+		ur->commit_action();
+	}
+
+	if (Object::cast_to<GPUParticlesCollisionBox>(sn) || Object::cast_to<GPUParticlesAttractorBox>(sn) || Object::cast_to<GPUParticlesAttractorVectorField>(sn) || Object::cast_to<GPUParticlesCollisionSDF>(sn) || Object::cast_to<GPUParticlesCollisionHeightField>(sn)) {
+		if (p_cancel) {
+			sn->call("set_extents", p_restore);
+			return;
+		}
+
+		UndoRedo *ur = Node3DEditor::get_singleton()->get_undo_redo();
+		ur->create_action(TTR("Change Box Shape Extents"));
+		ur->add_do_method(sn, "set_extents", sn->call("get_extents"));
+		ur->add_undo_method(sn, "set_extents", p_restore);
+		ur->commit_action();
+	}
+}
+
+void GPUParticlesCollision3DGizmoPlugin::redraw(EditorNode3DGizmo *p_gizmo) {
+	Node3D *cs = p_gizmo->get_spatial_node();
+
+	print_line("redraw request " + itos(cs != nullptr));
+	p_gizmo->clear();
+
+	const Ref<Material> material =
+			get_material("shape_material", p_gizmo);
+	const Ref<Material> material_internal =
+			get_material("shape_material_internal", p_gizmo);
+
+	Ref<Material> handles_material = get_material("handles");
+
+	if (Object::cast_to<GPUParticlesCollisionSphere>(cs) || Object::cast_to<GPUParticlesAttractorSphere>(cs)) {
+		float r = cs->call("get_radius");
+
+		Vector<Vector3> points;
+
+		for (int i = 0; i <= 360; i++) {
+			float ra = Math::deg2rad((float)i);
+			float rb = Math::deg2rad((float)i + 1);
+			Point2 a = Vector2(Math::sin(ra), Math::cos(ra)) * r;
+			Point2 b = Vector2(Math::sin(rb), Math::cos(rb)) * r;
+
+			points.push_back(Vector3(a.x, 0, a.y));
+			points.push_back(Vector3(b.x, 0, b.y));
+			points.push_back(Vector3(0, a.x, a.y));
+			points.push_back(Vector3(0, b.x, b.y));
+			points.push_back(Vector3(a.x, a.y, 0));
+			points.push_back(Vector3(b.x, b.y, 0));
+		}
+
+		Vector<Vector3> collision_segments;
+
+		for (int i = 0; i < 64; i++) {
+			float ra = i * Math_PI * 2.0 / 64.0;
+			float rb = (i + 1) * Math_PI * 2.0 / 64.0;
+			Point2 a = Vector2(Math::sin(ra), Math::cos(ra)) * r;
+			Point2 b = Vector2(Math::sin(rb), Math::cos(rb)) * r;
+
+			collision_segments.push_back(Vector3(a.x, 0, a.y));
+			collision_segments.push_back(Vector3(b.x, 0, b.y));
+			collision_segments.push_back(Vector3(0, a.x, a.y));
+			collision_segments.push_back(Vector3(0, b.x, b.y));
+			collision_segments.push_back(Vector3(a.x, a.y, 0));
+			collision_segments.push_back(Vector3(b.x, b.y, 0));
+		}
+
+		p_gizmo->add_lines(points, material);
+		p_gizmo->add_collision_segments(collision_segments);
+		Vector<Vector3> handles;
+		handles.push_back(Vector3(r, 0, 0));
+		p_gizmo->add_handles(handles, handles_material);
+	}
+
+	if (Object::cast_to<GPUParticlesCollisionBox>(cs) || Object::cast_to<GPUParticlesAttractorBox>(cs) || Object::cast_to<GPUParticlesAttractorVectorField>(cs) || Object::cast_to<GPUParticlesCollisionSDF>(cs) || Object::cast_to<GPUParticlesCollisionHeightField>(cs)) {
+		Vector<Vector3> lines;
+		AABB aabb;
+		aabb.position = -cs->call("get_extents").operator Vector3();
+		aabb.size = aabb.position * -2;
+
+		for (int i = 0; i < 12; i++) {
+			Vector3 a, b;
+			aabb.get_edge(i, a, b);
+			lines.push_back(a);
+			lines.push_back(b);
+		}
+
+		Vector<Vector3> handles;
+
+		for (int i = 0; i < 3; i++) {
+			Vector3 ax;
+			ax[i] = cs->call("get_extents").operator Vector3()[i];
+			handles.push_back(ax);
+		}
+
+		p_gizmo->add_lines(lines, material);
+		p_gizmo->add_collision_segments(lines);
+		p_gizmo->add_handles(handles, handles_material);
+
+		GPUParticlesCollisionSDF *col_sdf = Object::cast_to<GPUParticlesCollisionSDF>(cs);
+		if (col_sdf) {
+			static const int subdivs[GPUParticlesCollisionSDF::RESOLUTION_MAX] = { 16, 32, 64, 128, 256, 512 };
+			int subdiv = subdivs[col_sdf->get_resolution()];
+			float cell_size = aabb.get_longest_axis_size() / subdiv;
+
+			lines.clear();
+
+			for (int i = 1; i < subdiv; i++) {
+				for (int j = 0; j < 3; j++) {
+					if (cell_size * i > aabb.size[j]) {
+						continue;
+					}
+
+					Vector2 dir;
+					dir[j] = 1.0;
+					Vector2 ta, tb;
+					int j_n1 = (j + 1) % 3;
+					int j_n2 = (j + 2) % 3;
+					ta[j_n1] = 1.0;
+					tb[j_n2] = 1.0;
+
+					for (int k = 0; k < 4; k++) {
+						Vector3 from = aabb.position, to = aabb.position;
+						from[j] += cell_size * i;
+						to[j] += cell_size * i;
+
+						if (k & 1) {
+							to[j_n1] += aabb.size[j_n1];
+						} else {
+							to[j_n2] += aabb.size[j_n2];
+						}
+
+						if (k & 2) {
+							from[j_n1] += aabb.size[j_n1];
+							from[j_n2] += aabb.size[j_n2];
+						}
+
+						lines.push_back(from);
+						lines.push_back(to);
+					}
+				}
+			}
+
+			p_gizmo->add_lines(lines, material_internal);
+		}
+	}
+}
+
+/////
+
+////
+
 ReflectionProbeGizmoPlugin::ReflectionProbeGizmoPlugin() {
 	Color gizmo_color = EDITOR_DEF("editors/3d_gizmos/gizmo_colors/reflection_probe", Color(0.6, 1, 0.5));
 

editor/node_3d_editor_gizmos.h

@@ -253,6 +253,23 @@ public:
 	GPUParticles3DGizmoPlugin();
 };
 
+class GPUParticlesCollision3DGizmoPlugin : public EditorNode3DGizmoPlugin {
+	GDCLASS(GPUParticlesCollision3DGizmoPlugin, EditorNode3DGizmoPlugin);
+
+public:
+	bool has_gizmo(Node3D *p_spatial) override;
+	String get_name() const override;
+	int get_priority() const override;
+	void redraw(EditorNode3DGizmo *p_gizmo) override;
+
+	String get_handle_name(const EditorNode3DGizmo *p_gizmo, int p_idx) const override;
+	Variant get_handle_value(EditorNode3DGizmo *p_gizmo, int p_idx) const override;
+	void set_handle(EditorNode3DGizmo *p_gizmo, int p_idx, Camera3D *p_camera, const Point2 &p_point) override;
+	void commit_handle(EditorNode3DGizmo *p_gizmo, int p_idx, const Variant &p_restore, bool p_cancel = false) override;
+
+	GPUParticlesCollision3DGizmoPlugin();
+};
+
 class ReflectionProbeGizmoPlugin : public EditorNode3DGizmoPlugin {
 	GDCLASS(ReflectionProbeGizmoPlugin, EditorNode3DGizmoPlugin);
 

editor/plugins/gpu_particles_collision_sdf_editor_plugin.cpp

@@ -0,0 +1,201 @@
+/*************************************************************************/
+/*  gpu_particles_collision_sdf_editor_plugin.cpp                        */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "gpu_particles_collision_sdf_editor_plugin.h"
+
+void GPUParticlesCollisionSDFEditorPlugin::_bake() {
+	if (col_sdf) {
+		if (col_sdf->get_texture().is_null() || !col_sdf->get_texture()->get_path().is_resource_file()) {
+			String path = get_tree()->get_edited_scene_root()->get_filename();
+			if (path == String()) {
+				path = "res://" + col_sdf->get_name() + "_data.exr";
+			} else {
+				String ext = path.get_extension();
+				path = path.get_basename() + "." + col_sdf->get_name() + "_data.exr";
+			}
+			probe_file->set_current_path(path);
+			probe_file->popup_file_dialog();
+			return;
+		}
+
+		_sdf_save_path_and_bake(col_sdf->get_texture()->get_path());
+	}
+}
+
+void GPUParticlesCollisionSDFEditorPlugin::edit(Object *p_object) {
+	GPUParticlesCollisionSDF *s = Object::cast_to<GPUParticlesCollisionSDF>(p_object);
+	if (!s) {
+		return;
+	}
+
+	col_sdf = s;
+}
+
+bool GPUParticlesCollisionSDFEditorPlugin::handles(Object *p_object) const {
+	return p_object->is_class("GPUParticlesCollisionSDF");
+}
+
+void GPUParticlesCollisionSDFEditorPlugin::_notification(int p_what) {
+	if (p_what == NOTIFICATION_PROCESS) {
+		if (!col_sdf) {
+			return;
+		}
+
+		const Vector3i size = col_sdf->get_estimated_cell_size();
+		String text = vformat(String::utf8("%d × %d × %d"), size.x, size.y, size.z);
+		int data_size = 2;
+
+		const double size_mb = size.x * size.y * size.z * data_size / (1024.0 * 1024.0);
+		text += " - " + vformat(TTR("VRAM Size: %s MB"), String::num(size_mb, 2));
+
+		if (bake_info->get_text() == text) {
+			return;
+		}
+
+		// Color the label depending on the estimated performance level.
+		Color color;
+		if (size_mb <= 16.0 + CMP_EPSILON) {
+			// Fast.
+			color = bake_info->get_theme_color("success_color", "Editor");
+		} else if (size_mb <= 64.0 + CMP_EPSILON) {
+			// Medium.
+			color = bake_info->get_theme_color("warning_color", "Editor");
+		} else {
+			// Slow.
+			color = bake_info->get_theme_color("error_color", "Editor");
+		}
+		bake_info->add_theme_color_override("font_color", color);
+
+		bake_info->set_text(text);
+	}
+}
+
+void GPUParticlesCollisionSDFEditorPlugin::make_visible(bool p_visible) {
+	if (p_visible) {
+		bake_hb->show();
+		set_process(true);
+	} else {
+		bake_hb->hide();
+		set_process(false);
+	}
+}
+
+EditorProgress *GPUParticlesCollisionSDFEditorPlugin::tmp_progress = nullptr;
+
+void GPUParticlesCollisionSDFEditorPlugin::bake_func_begin(int p_steps) {
+	ERR_FAIL_COND(tmp_progress != nullptr);
+
+	tmp_progress = memnew(EditorProgress("bake_sdf", TTR("Bake SDF"), p_steps));
+}
+
+void GPUParticlesCollisionSDFEditorPlugin::bake_func_step(int p_step, const String &p_description) {
+	ERR_FAIL_COND(tmp_progress == nullptr);
+	tmp_progress->step(p_description, p_step, false);
+}
+
+void GPUParticlesCollisionSDFEditorPlugin::bake_func_end() {
+	ERR_FAIL_COND(tmp_progress == nullptr);
+	memdelete(tmp_progress);
+	tmp_progress = nullptr;
+}
+
+void GPUParticlesCollisionSDFEditorPlugin::_sdf_save_path_and_bake(const String &p_path) {
+	probe_file->hide();
+	if (col_sdf) {
+		Ref<Image> bake_img = col_sdf->bake();
+		if (bake_img.is_null()) {
+			EditorNode::get_singleton()->show_warning("Bake Error.");
+			return;
+		}
+
+		Ref<ConfigFile> config;
+
+		config.instance();
+		if (FileAccess::exists(p_path + ".import")) {
+			config->load(p_path + ".import");
+		}
+
+		config->set_value("remap", "importer", "3d_texture");
+		config->set_value("remap", "type", "StreamTexture3D");
+		if (!config->has_section_key("params", "compress/mode")) {
+			config->set_value("params", "compress/mode", 3); //user may want another compression, so leave it be
+		}
+		config->set_value("params", "compress/channel_pack", 1);
+		config->set_value("params", "mipmaps/generate", false);
+		config->set_value("params", "slices/horizontal", 1);
+		config->set_value("params", "slices/vertical", bake_img->get_meta("depth"));
+
+		config->save(p_path + ".import");
+
+		Error err = bake_img->save_exr(p_path, false);
+		ERR_FAIL_COND(err);
+		ResourceLoader::import(p_path);
+		Ref<Texture> t = ResourceLoader::load(p_path); //if already loaded, it will be updated on refocus?
+		ERR_FAIL_COND(t.is_null());
+
+		col_sdf->set_texture(t);
+	}
+}
+
+void GPUParticlesCollisionSDFEditorPlugin::_bind_methods() {
+}
+
+GPUParticlesCollisionSDFEditorPlugin::GPUParticlesCollisionSDFEditorPlugin(EditorNode *p_node) {
+	editor = p_node;
+	bake_hb = memnew(HBoxContainer);
+	bake_hb->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+	bake_hb->hide();
+	bake = memnew(Button);
+	bake->set_flat(true);
+	bake->set_icon(editor->get_gui_base()->get_theme_icon("Bake", "EditorIcons"));
+	bake->set_text(TTR("Bake SDF"));
+	bake->connect("pressed", callable_mp(this, &GPUParticlesCollisionSDFEditorPlugin::_bake));
+	bake_hb->add_child(bake);
+	bake_info = memnew(Label);
+	bake_info->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+	bake_info->set_clip_text(true);
+	bake_hb->add_child(bake_info);
+
+	add_control_to_container(CONTAINER_SPATIAL_EDITOR_MENU, bake_hb);
+	col_sdf = nullptr;
+	probe_file = memnew(EditorFileDialog);
+	probe_file->set_file_mode(EditorFileDialog::FILE_MODE_SAVE_FILE);
+	probe_file->add_filter("*.exr");
+	probe_file->connect("file_selected", callable_mp(this, &GPUParticlesCollisionSDFEditorPlugin::_sdf_save_path_and_bake));
+	get_editor_interface()->get_base_control()->add_child(probe_file);
+	probe_file->set_title(TTR("Select path for SDF Texture"));
+
+	GPUParticlesCollisionSDF::bake_begin_function = bake_func_begin;
+	GPUParticlesCollisionSDF::bake_step_function = bake_func_step;
+	GPUParticlesCollisionSDF::bake_end_function = bake_func_end;
+}
+
+GPUParticlesCollisionSDFEditorPlugin::~GPUParticlesCollisionSDFEditorPlugin() {
+}

editor/plugins/gpu_particles_collision_sdf_editor_plugin.h

@@ -0,0 +1,74 @@
+/*************************************************************************/
+/*  gpu_particles_collision_sdf_editor_plugin.h                          */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef GPU_PARTICLES_COLLISION_SDF_EDITOR_PLUGIN_H
+#define GPU_PARTICLES_COLLISION_SDF_EDITOR_PLUGIN_H
+
+#include "editor/editor_node.h"
+#include "editor/editor_plugin.h"
+#include "scene/3d/gpu_particles_collision_3d.h"
+#include "scene/resources/material.h"
+
+class GPUParticlesCollisionSDFEditorPlugin : public EditorPlugin {
+	GDCLASS(GPUParticlesCollisionSDFEditorPlugin, EditorPlugin);
+
+	GPUParticlesCollisionSDF *col_sdf;
+
+	HBoxContainer *bake_hb;
+	Label *bake_info;
+	Button *bake;
+	EditorNode *editor;
+
+	EditorFileDialog *probe_file;
+
+	static EditorProgress *tmp_progress;
+	static void bake_func_begin(int p_steps);
+	static void bake_func_step(int p_step, const String &p_description);
+	static void bake_func_end();
+
+	void _bake();
+	void _sdf_save_path_and_bake(const String &p_path);
+
+protected:
+	static void _bind_methods();
+	void _notification(int p_what);
+
+public:
+	virtual String get_name() const override { return "GPUParticlesCollisionSDF"; }
+	bool has_main_screen() const override { return false; }
+	virtual void edit(Object *p_object) override;
+	virtual bool handles(Object *p_object) const override;
+	virtual void make_visible(bool p_visible) override;
+
+	GPUParticlesCollisionSDFEditorPlugin(EditorNode *p_node);
+	~GPUParticlesCollisionSDFEditorPlugin();
+};
+
+#endif // GPU_PARTICLES_COLLISION_SDF_EDITOR_PLUGIN_H

editor/plugins/node_3d_editor_plugin.cpp

@@ -6092,6 +6092,7 @@ void Node3DEditor::_register_all_gizmos() {
 	add_gizmo_plugin(Ref<VehicleWheel3DGizmoPlugin>(memnew(VehicleWheel3DGizmoPlugin)));
 	add_gizmo_plugin(Ref<VisibilityNotifier3DGizmoPlugin>(memnew(VisibilityNotifier3DGizmoPlugin)));
 	add_gizmo_plugin(Ref<GPUParticles3DGizmoPlugin>(memnew(GPUParticles3DGizmoPlugin)));
+	add_gizmo_plugin(Ref<GPUParticlesCollision3DGizmoPlugin>(memnew(GPUParticlesCollision3DGizmoPlugin)));
 	add_gizmo_plugin(Ref<CPUParticles3DGizmoPlugin>(memnew(CPUParticles3DGizmoPlugin)));
 	add_gizmo_plugin(Ref<ReflectionProbeGizmoPlugin>(memnew(ReflectionProbeGizmoPlugin)));
 	add_gizmo_plugin(Ref<DecalGizmoPlugin>(memnew(DecalGizmoPlugin)));

scene/3d/gpu_particles_3d.cpp

@@ -124,6 +124,11 @@ void GPUParticles3D::set_speed_scale(float p_scale) {
 	RS::get_singleton()->particles_set_speed_scale(particles, p_scale);
 }
 
+void GPUParticles3D::set_collision_base_size(float p_size) {
+	collision_base_size = p_size;
+	RS::get_singleton()->particles_set_collision_base_size(particles, p_size);
+}
+
 bool GPUParticles3D::is_emitting() const {
 	return RS::get_singleton()->particles_get_emitting(particles);
 }
@@ -168,6 +173,10 @@ float GPUParticles3D::get_speed_scale() const {
 	return speed_scale;
 }
 
+float GPUParticles3D::get_collision_base_size() const {
+	return collision_base_size;
+}
+
 void GPUParticles3D::set_draw_order(DrawOrder p_order) {
 	draw_order = p_order;
 	RS::get_singleton()->particles_set_draw_order(particles, RS::ParticlesDrawOrder(p_order));
@@ -381,6 +390,7 @@ void GPUParticles3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_fractional_delta", "enable"), &GPUParticles3D::set_fractional_delta);
 	ClassDB::bind_method(D_METHOD("set_process_material", "material"), &GPUParticles3D::set_process_material);
 	ClassDB::bind_method(D_METHOD("set_speed_scale", "scale"), &GPUParticles3D::set_speed_scale);
+	ClassDB::bind_method(D_METHOD("set_collision_base_size", "size"), &GPUParticles3D::set_collision_base_size);
 
 	ClassDB::bind_method(D_METHOD("is_emitting"), &GPUParticles3D::is_emitting);
 	ClassDB::bind_method(D_METHOD("get_amount"), &GPUParticles3D::get_amount);
@@ -395,6 +405,7 @@ void GPUParticles3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_fractional_delta"), &GPUParticles3D::get_fractional_delta);
 	ClassDB::bind_method(D_METHOD("get_process_material"), &GPUParticles3D::get_process_material);
 	ClassDB::bind_method(D_METHOD("get_speed_scale"), &GPUParticles3D::get_speed_scale);
+	ClassDB::bind_method(D_METHOD("get_collision_base_size"), &GPUParticles3D::get_collision_base_size);
 
 	ClassDB::bind_method(D_METHOD("set_draw_order", "order"), &GPUParticles3D::set_draw_order);
 
@@ -426,6 +437,8 @@ void GPUParticles3D::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "randomness", PROPERTY_HINT_RANGE, "0,1,0.01"), "set_randomness_ratio", "get_randomness_ratio");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "fixed_fps", PROPERTY_HINT_RANGE, "0,1000,1"), "set_fixed_fps", "get_fixed_fps");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "fract_delta"), "set_fractional_delta", "get_fractional_delta");
+	ADD_GROUP("Collision", "collision_");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "collision_base_size", PROPERTY_HINT_RANGE, "0,128,0.01,or_greater"), "set_collision_base_size", "get_collision_base_size");
 	ADD_GROUP("Drawing", "");
 	ADD_PROPERTY(PropertyInfo(Variant::AABB, "visibility_aabb"), "set_visibility_aabb", "get_visibility_aabb");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "local_coords"), "set_use_local_coordinates", "get_use_local_coordinates");
@@ -469,6 +482,7 @@ GPUParticles3D::GPUParticles3D() {
 	set_draw_passes(1);
 	set_draw_order(DRAW_ORDER_INDEX);
 	set_speed_scale(1);
+	set_collision_base_size(0.01);
 }
 
 GPUParticles3D::~GPUParticles3D() {

scene/3d/gpu_particles_3d.h

@@ -65,6 +65,7 @@ private:
 	int fixed_fps;
 	bool fractional_delta;
 	NodePath sub_emitter;
+	float collision_base_size;
 
 	Ref<Material> process_material;
 
@@ -94,6 +95,7 @@ public:
 	void set_use_local_coordinates(bool p_enable);
 	void set_process_material(const Ref<Material> &p_material);
 	void set_speed_scale(float p_scale);
+	void set_collision_base_size(float p_ratio);
 
 	bool is_emitting() const;
 	int get_amount() const;
@@ -106,6 +108,7 @@ public:
 	bool get_use_local_coordinates() const;
 	Ref<Material> get_process_material() const;
 	float get_speed_scale() const;
+	float get_collision_base_size() const;
 
 	void set_fixed_fps(int p_count);
 	int get_fixed_fps() const;

scene/3d/gpu_particles_collision_3d.cpp

@@ -0,0 +1,897 @@
+/*************************************************************************/
+/*  gpu_particles_collision_3d.cpp                                       */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "gpu_particles_collision_3d.h"
+#include "core/thread_work_pool.h"
+#include "mesh_instance_3d.h"
+#include "scene/3d/camera_3d.h"
+#include "scene/main/viewport.h"
+
+void GPUParticlesCollision3D::set_cull_mask(uint32_t p_cull_mask) {
+	cull_mask = p_cull_mask;
+	RS::get_singleton()->particles_collision_set_cull_mask(collision, p_cull_mask);
+}
+
+uint32_t GPUParticlesCollision3D::get_cull_mask() const {
+	return cull_mask;
+}
+
+void GPUParticlesCollision3D::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_cull_mask", "mask"), &GPUParticlesCollision3D::set_cull_mask);
+	ClassDB::bind_method(D_METHOD("get_cull_mask"), &GPUParticlesCollision3D::get_cull_mask);
+
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "cull_mask", PROPERTY_HINT_LAYERS_3D_RENDER), "set_cull_mask", "get_cull_mask");
+}
+
+GPUParticlesCollision3D::GPUParticlesCollision3D(RS::ParticlesCollisionType p_type) {
+	collision = RS::get_singleton()->particles_collision_create();
+	RS::get_singleton()->particles_collision_set_collision_type(collision, p_type);
+	set_base(collision);
+}
+
+GPUParticlesCollision3D::~GPUParticlesCollision3D() {
+	RS::get_singleton()->free(collision);
+}
+
+/////////////////////////////////
+
+void GPUParticlesCollisionSphere::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_radius", "radius"), &GPUParticlesCollisionSphere::set_radius);
+	ClassDB::bind_method(D_METHOD("get_radius"), &GPUParticlesCollisionSphere::get_radius);
+
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "radius", PROPERTY_HINT_RANGE, "0.01,1024,0.01,or_greater"), "set_radius", "get_radius");
+}
+
+void GPUParticlesCollisionSphere::set_radius(float p_radius) {
+	radius = p_radius;
+	RS::get_singleton()->particles_collision_set_sphere_radius(_get_collision(), radius);
+	update_gizmo();
+}
+
+float GPUParticlesCollisionSphere::get_radius() const {
+	return radius;
+}
+
+AABB GPUParticlesCollisionSphere::get_aabb() const {
+	return AABB(Vector3(-radius, -radius, -radius), Vector3(radius * 2, radius * 2, radius * 2));
+}
+
+GPUParticlesCollisionSphere::GPUParticlesCollisionSphere() :
+		GPUParticlesCollision3D(RS::PARTICLES_COLLISION_TYPE_SPHERE_COLLIDE) {
+}
+
+GPUParticlesCollisionSphere::~GPUParticlesCollisionSphere() {
+}
+
+///////////////////////////
+
+void GPUParticlesCollisionBox::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_extents", "extents"), &GPUParticlesCollisionBox::set_extents);
+	ClassDB::bind_method(D_METHOD("get_extents"), &GPUParticlesCollisionBox::get_extents);
+
+	ADD_PROPERTY(PropertyInfo(Variant::VECTOR3, "extents", PROPERTY_HINT_RANGE, "0.01,1024,0.01,or_greater"), "set_extents", "get_extents");
+}
+
+void GPUParticlesCollisionBox::set_extents(const Vector3 &p_extents) {
+	extents = p_extents;
+	RS::get_singleton()->particles_collision_set_box_extents(_get_collision(), extents);
+	update_gizmo();
+}
+
+Vector3 GPUParticlesCollisionBox::get_extents() const {
+	return extents;
+}
+
+AABB GPUParticlesCollisionBox::get_aabb() const {
+	return AABB(-extents, extents * 2);
+}
+
+GPUParticlesCollisionBox::GPUParticlesCollisionBox() :
+		GPUParticlesCollision3D(RS::PARTICLES_COLLISION_TYPE_BOX_COLLIDE) {
+}
+
+GPUParticlesCollisionBox::~GPUParticlesCollisionBox() {
+}
+
+///////////////////////////////
+///////////////////////////
+
+void GPUParticlesCollisionSDF::_find_meshes(const AABB &p_aabb, Node *p_at_node, List<PlotMesh> &plot_meshes) {
+	MeshInstance3D *mi = Object::cast_to<MeshInstance3D>(p_at_node);
+	if (mi && mi->is_visible_in_tree()) {
+		Ref<Mesh> mesh = mi->get_mesh();
+		if (mesh.is_valid()) {
+			AABB aabb = mesh->get_aabb();
+
+			Transform xf = get_global_transform().affine_inverse() * mi->get_global_transform();
+
+			if (p_aabb.intersects(xf.xform(aabb))) {
+				PlotMesh pm;
+				pm.local_xform = xf;
+				pm.mesh = mesh;
+				plot_meshes.push_back(pm);
+			}
+		}
+	}
+
+	Node3D *s = Object::cast_to<Node3D>(p_at_node);
+	if (s) {
+		if (s->is_visible_in_tree()) {
+			Array meshes = p_at_node->call("get_meshes");
+			for (int i = 0; i < meshes.size(); i += 2) {
+				Transform mxf = meshes[i];
+				Ref<Mesh> mesh = meshes[i + 1];
+				if (!mesh.is_valid()) {
+					continue;
+				}
+
+				AABB aabb = mesh->get_aabb();
+
+				Transform xf = get_global_transform().affine_inverse() * (s->get_global_transform() * mxf);
+
+				if (p_aabb.intersects(xf.xform(aabb))) {
+					PlotMesh pm;
+					pm.local_xform = xf;
+					pm.mesh = mesh;
+					plot_meshes.push_back(pm);
+				}
+			}
+		}
+	}
+
+	for (int i = 0; i < p_at_node->get_child_count(); i++) {
+		Node *child = p_at_node->get_child(i);
+		_find_meshes(p_aabb, child, plot_meshes);
+	}
+}
+
+uint32_t GPUParticlesCollisionSDF::_create_bvh(LocalVector<BVH> &bvh_tree, FacePos *p_faces, uint32_t p_face_count, const Face3 *p_triangles, float p_thickness) {
+	if (p_face_count == 1) {
+		return BVH::LEAF_BIT | p_faces[0].index;
+	}
+
+	uint32_t index = bvh_tree.size();
+	{
+		BVH bvh;
+
+		for (uint32_t i = 0; i < p_face_count; i++) {
+			const Face3 &f = p_triangles[p_faces[i].index];
+			AABB aabb(f.vertex[0], Vector3());
+			aabb.expand_to(f.vertex[1]);
+			aabb.expand_to(f.vertex[2]);
+			if (p_thickness > 0.0) {
+				Vector3 normal = p_triangles[p_faces[i].index].get_plane().normal;
+				aabb.expand_to(f.vertex[0] - normal * p_thickness);
+				aabb.expand_to(f.vertex[1] - normal * p_thickness);
+				aabb.expand_to(f.vertex[2] - normal * p_thickness);
+			}
+			if (i == 0) {
+				bvh.bounds = aabb;
+			} else {
+				bvh.bounds.merge_with(aabb);
+			}
+		}
+		bvh_tree.push_back(bvh);
+	}
+
+	uint32_t middle = p_face_count / 2;
+
+	SortArray<FacePos, FaceSort> s;
+	s.compare.axis = bvh_tree[index].bounds.get_longest_axis_index();
+	s.sort(p_faces, p_face_count);
+
+	uint32_t left = _create_bvh(bvh_tree, p_faces, middle, p_triangles, p_thickness);
+	uint32_t right = _create_bvh(bvh_tree, p_faces + middle, p_face_count - middle, p_triangles, p_thickness);
+
+	bvh_tree[index].children[0] = left;
+	bvh_tree[index].children[1] = right;
+
+	return index;
+}
+
+static _FORCE_INLINE_ float Vector3_dot2(const Vector3 &p_vec3) {
+	return p_vec3.dot(p_vec3);
+}
+
+void GPUParticlesCollisionSDF::_find_closest_distance(const Vector3 &p_pos, const BVH *bvh, uint32_t p_bvh_cell, const Face3 *triangles, float thickness, float &closest_distance) {
+	if (p_bvh_cell & BVH::LEAF_BIT) {
+		p_bvh_cell &= BVH::LEAF_MASK; //remove bit
+
+		Vector3 point = p_pos;
+		Plane p = triangles[p_bvh_cell].get_plane();
+		float d = p.distance_to(point);
+		float inside_d = 1e20;
+		if (d < 0 && d > -thickness) {
+			//inside planes, do this in 2D
+
+			Vector3 x_axis = (triangles[p_bvh_cell].vertex[0] - triangles[p_bvh_cell].vertex[1]).normalized();
+			Vector3 y_axis = p.normal.cross(x_axis).normalized();
+
+			Vector2 points[3];
+			for (int i = 0; i < 3; i++) {
+				points[i] = Vector2(x_axis.dot(triangles[p_bvh_cell].vertex[i]), y_axis.dot(triangles[p_bvh_cell].vertex[i]));
+			}
+
+			Vector2 p2d = Vector2(x_axis.dot(point), y_axis.dot(point));
+
+			{
+				// https://www.shadertoy.com/view/XsXSz4
+
+				Vector2 e0 = points[1] - points[0];
+				Vector2 e1 = points[2] - points[1];
+				Vector2 e2 = points[0] - points[2];
+
+				Vector2 v0 = p2d - points[0];
+				Vector2 v1 = p2d - points[1];
+				Vector2 v2 = p2d - points[2];
+
+				Vector2 pq0 = v0 - e0 * CLAMP(v0.dot(e0) / e0.dot(e0), 0.0, 1.0);
+				Vector2 pq1 = v1 - e1 * CLAMP(v1.dot(e1) / e1.dot(e1), 0.0, 1.0);
+				Vector2 pq2 = v2 - e2 * CLAMP(v2.dot(e2) / e2.dot(e2), 0.0, 1.0);
+
+				float s = SGN(e0.x * e2.y - e0.y * e2.x);
+				Vector2 d2 = Vector2(pq0.dot(pq0), s * (v0.x * e0.y - v0.y * e0.x)).min(Vector2(pq1.dot(pq1), s * (v1.x * e1.y - v1.y * e1.x))).min(Vector2(pq2.dot(pq2), s * (v2.x * e2.y - v2.y * e2.x)));
+
+				inside_d = -Math::sqrt(d2.x) * SGN(d2.y);
+			}
+
+			//make sure distance to planes is not shorter if inside
+			if (inside_d < 0) {
+				inside_d = MAX(inside_d, d);
+				inside_d = MAX(inside_d, -(thickness + d));
+			}
+
+			closest_distance = MIN(closest_distance, inside_d);
+		} else {
+			if (d < 0) {
+				point -= p.normal * thickness; //flatten
+			}
+
+			// https://iquilezles.org/www/articles/distfunctions/distfunctions.htm
+			Vector3 a = triangles[p_bvh_cell].vertex[0];
+			Vector3 b = triangles[p_bvh_cell].vertex[1];
+			Vector3 c = triangles[p_bvh_cell].vertex[2];
+
+			Vector3 ba = b - a;
+			Vector3 pa = point - a;
+			Vector3 cb = c - b;
+			Vector3 pb = point - b;
+			Vector3 ac = a - c;
+			Vector3 pc = point - c;
+			Vector3 nor = ba.cross(ac);
+
+			inside_d = Math::sqrt(
+					(SGN(ba.cross(nor).dot(pa)) +
+									SGN(cb.cross(nor).dot(pb)) +
+									SGN(ac.cross(nor).dot(pc)) <
+							2.0) ?
+							MIN(MIN(
+										Vector3_dot2(ba * CLAMP(ba.dot(pa) / Vector3_dot2(ba), 0.0, 1.0) - pa),
+										Vector3_dot2(cb * CLAMP(cb.dot(pb) / Vector3_dot2(cb), 0.0, 1.0) - pb)),
+									Vector3_dot2(ac * CLAMP(ac.dot(pc) / Vector3_dot2(ac), 0.0, 1.0) - pc)) :
+							nor.dot(pa) * nor.dot(pa) / Vector3_dot2(nor));
+
+			closest_distance = MIN(closest_distance, inside_d);
+		}
+
+	} else {
+		bool pass = true;
+		if (!bvh[p_bvh_cell].bounds.has_point(p_pos)) {
+			//outside, find closest point
+			Vector3 he = bvh[p_bvh_cell].bounds.size * 0.5;
+			Vector3 center = bvh[p_bvh_cell].bounds.position + he;
+
+			Vector3 rel = (p_pos - center).abs();
+			Vector3 closest(MIN(rel.x, he.x), MIN(rel.y, he.y), MIN(rel.z, he.z));
+			float d = rel.distance_to(closest);
+
+			if (d >= closest_distance) {
+				pass = false; //already closer than this aabb, discard
+			}
+		}
+
+		if (pass) {
+			_find_closest_distance(p_pos, bvh, bvh[p_bvh_cell].children[0], triangles, thickness, closest_distance);
+			_find_closest_distance(p_pos, bvh, bvh[p_bvh_cell].children[1], triangles, thickness, closest_distance);
+		}
+	}
+}
+
+void GPUParticlesCollisionSDF::_compute_sdf_z(uint32_t p_z, ComputeSDFParams *params) {
+	int32_t z_ofs = p_z * params->size.y * params->size.x;
+	for (int32_t y = 0; y < params->size.y; y++) {
+		int32_t y_ofs = z_ofs + y * params->size.x;
+		for (int32_t x = 0; x < params->size.x; x++) {
+			int32_t x_ofs = y_ofs + x;
+			float &cell = params->cells[x_ofs];
+
+			Vector3 pos = params->cell_offset + Vector3(x, y, p_z) * params->cell_size;
+
+			cell = 1e20;
+
+			_find_closest_distance(pos, params->bvh, 0, params->triangles, params->thickness, cell);
+		}
+	}
+}
+
+void GPUParticlesCollisionSDF::_compute_sdf(ComputeSDFParams *params) {
+	ThreadWorkPool work_pool;
+	work_pool.init();
+	work_pool.begin_work(params->size.z, this, &GPUParticlesCollisionSDF::_compute_sdf_z, params);
+	while (work_pool.get_work_index() < (uint32_t)params->size.z) {
+		OS::get_singleton()->delay_usec(10000);
+		bake_step_function(work_pool.get_work_index() * 100 / params->size.z, "Baking SDF");
+	}
+	work_pool.end_work();
+	work_pool.finish();
+}
+
+Vector3i GPUParticlesCollisionSDF::get_estimated_cell_size() const {
+	static const int subdivs[RESOLUTION_MAX] = { 16, 32, 64, 128, 256, 512 };
+	int subdiv = subdivs[get_resolution()];
+
+	AABB aabb(-extents, extents * 2);
+
+	float cell_size = aabb.get_longest_axis_size() / float(subdiv);
+
+	Vector3i sdf_size = Vector3i(aabb.size / cell_size);
+	sdf_size.x = MAX(1, sdf_size.x);
+	sdf_size.y = MAX(1, sdf_size.y);
+	sdf_size.z = MAX(1, sdf_size.z);
+	return sdf_size;
+}
+
+Ref<Image> GPUParticlesCollisionSDF::bake() {
+	static const int subdivs[RESOLUTION_MAX] = { 16, 32, 64, 128, 256, 512 };
+	int subdiv = subdivs[get_resolution()];
+
+	AABB aabb(-extents, extents * 2);
+
+	float cell_size = aabb.get_longest_axis_size() / float(subdiv);
+
+	Vector3i sdf_size = Vector3i(aabb.size / cell_size);
+	sdf_size.x = MAX(1, sdf_size.x);
+	sdf_size.y = MAX(1, sdf_size.y);
+	sdf_size.z = MAX(1, sdf_size.z);
+
+	if (bake_begin_function) {
+		bake_begin_function(100);
+	}
+
+	aabb.size = Vector3(sdf_size) * cell_size;
+
+	List<PlotMesh> plot_meshes;
+	_find_meshes(aabb, get_parent(), plot_meshes);
+
+	LocalVector<Face3> faces;
+
+	if (bake_step_function) {
+		bake_step_function(0, "Finding Meshes");
+	}
+
+	for (List<PlotMesh>::Element *E = plot_meshes.front(); E; E = E->next()) {
+		const PlotMesh &pm = E->get();
+
+		for (int i = 0; i < pm.mesh->get_surface_count(); i++) {
+			if (pm.mesh->surface_get_primitive_type(i) != Mesh::PRIMITIVE_TRIANGLES) {
+				continue; //only triangles
+			}
+
+			Array a = pm.mesh->surface_get_arrays(i);
+
+			Vector<Vector3> vertices = a[Mesh::ARRAY_VERTEX];
+			const Vector3 *vr = vertices.ptr();
+			Vector<int> index = a[Mesh::ARRAY_INDEX];
+
+			if (index.size()) {
+				int facecount = index.size() / 3;
+				const int *ir = index.ptr();
+
+				for (int j = 0; j < facecount; j++) {
+					Face3 face;
+
+					for (int k = 0; k < 3; k++) {
+						face.vertex[k] = pm.local_xform.xform(vr[ir[j * 3 + k]]);
+					}
+
+					//test against original bounds
+					if (!Geometry3D::triangle_box_overlap(aabb.position + aabb.size * 0.5, aabb.size * 0.5, face.vertex)) {
+						continue;
+					}
+
+					faces.push_back(face);
+				}
+
+			} else {
+				int facecount = vertices.size() / 3;
+
+				for (int j = 0; j < facecount; j++) {
+					Face3 face;
+
+					for (int k = 0; k < 3; k++) {
+						face.vertex[k] = pm.local_xform.xform(vr[j * 3 + k]);
+					}
+
+					//test against original bounds
+					if (!Geometry3D::triangle_box_overlap(aabb.position + aabb.size * 0.5, aabb.size * 0.5, face.vertex)) {
+						continue;
+					}
+
+					faces.push_back(face);
+				}
+			}
+		}
+	}
+
+	//compute bvh
+
+	ERR_FAIL_COND_V(faces.size() <= 1, Ref<Image>());
+
+	LocalVector<FacePos> face_pos;
+
+	face_pos.resize(faces.size());
+
+	float th = cell_size * thickness;
+
+	for (uint32_t i = 0; i < faces.size(); i++) {
+		face_pos[i].index = i;
+		face_pos[i].center = (faces[i].vertex[0] + faces[i].vertex[1] + faces[i].vertex[2]) / 2;
+		if (th > 0.0) {
+			face_pos[i].center -= faces[i].get_plane().normal * th * 0.5;
+		}
+	}
+
+	if (bake_step_function) {
+		bake_step_function(0, "Creating BVH");
+	}
+
+	LocalVector<BVH> bvh;
+
+	_create_bvh(bvh, face_pos.ptr(), face_pos.size(), faces.ptr(), th);
+
+	Vector<uint8_t> data;
+	data.resize(sdf_size.z * sdf_size.y * sdf_size.x * sizeof(float));
+
+	if (bake_step_function) {
+		bake_step_function(0, "Baking SDF");
+	}
+
+	ComputeSDFParams params;
+	params.cells = (float *)data.ptrw();
+	params.size = sdf_size;
+	params.cell_size = cell_size;
+	params.cell_offset = aabb.position + Vector3(cell_size * 0.5, cell_size * 0.5, cell_size * 0.5);
+	params.bvh = bvh.ptr();
+	params.triangles = faces.ptr();
+	params.thickness = th;
+	_compute_sdf(&params);
+
+	Ref<Image> ret;
+	ret.instance();
+	ret->create(sdf_size.x, sdf_size.y * sdf_size.z, false, Image::FORMAT_RF, data);
+	ret->convert(Image::FORMAT_RH); //convert to half, save space
+	ret->set_meta("depth", sdf_size.z); //hack, make sure to add to the docs of this function
+
+	if (bake_end_function) {
+		bake_end_function();
+	}
+
+	return ret;
+}
+
+void GPUParticlesCollisionSDF::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_extents", "extents"), &GPUParticlesCollisionSDF::set_extents);
+	ClassDB::bind_method(D_METHOD("get_extents"), &GPUParticlesCollisionSDF::get_extents);
+
+	ClassDB::bind_method(D_METHOD("set_resolution", "resolution"), &GPUParticlesCollisionSDF::set_resolution);
+	ClassDB::bind_method(D_METHOD("get_resolution"), &GPUParticlesCollisionSDF::get_resolution);
+
+	ClassDB::bind_method(D_METHOD("set_texture", "texture"), &GPUParticlesCollisionSDF::set_texture);
+	ClassDB::bind_method(D_METHOD("get_texture"), &GPUParticlesCollisionSDF::get_texture);
+
+	ClassDB::bind_method(D_METHOD("set_thickness", "thickness"), &GPUParticlesCollisionSDF::set_thickness);
+	ClassDB::bind_method(D_METHOD("get_thickness"), &GPUParticlesCollisionSDF::get_thickness);
+
+	ADD_PROPERTY(PropertyInfo(Variant::VECTOR3, "extents", PROPERTY_HINT_RANGE, "0.01,1024,0.01,or_greater"), "set_extents", "get_extents");
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "resolution", PROPERTY_HINT_ENUM, "16,32,64,128,256,512"), "set_resolution", "get_resolution");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "thickness", PROPERTY_HINT_RANGE, "0.0,2.0,0.01"), "set_thickness", "get_thickness");
+	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "texture", PROPERTY_HINT_RESOURCE_TYPE, "Texture3D"), "set_texture", "get_texture");
+
+	BIND_ENUM_CONSTANT(RESOLUTION_16);
+	BIND_ENUM_CONSTANT(RESOLUTION_32);
+	BIND_ENUM_CONSTANT(RESOLUTION_64);
+	BIND_ENUM_CONSTANT(RESOLUTION_128);
+	BIND_ENUM_CONSTANT(RESOLUTION_256);
+	BIND_ENUM_CONSTANT(RESOLUTION_512);
+	BIND_ENUM_CONSTANT(RESOLUTION_MAX);
+}
+
+void GPUParticlesCollisionSDF::set_thickness(float p_thickness) {
+	thickness = p_thickness;
+}
+
+float GPUParticlesCollisionSDF::get_thickness() const {
+	return thickness;
+}
+
+void GPUParticlesCollisionSDF::set_extents(const Vector3 &p_extents) {
+	extents = p_extents;
+	RS::get_singleton()->particles_collision_set_box_extents(_get_collision(), extents);
+	update_gizmo();
+}
+
+Vector3 GPUParticlesCollisionSDF::get_extents() const {
+	return extents;
+}
+
+void GPUParticlesCollisionSDF::set_resolution(Resolution p_resolution) {
+	resolution = p_resolution;
+	update_gizmo();
+}
+
+GPUParticlesCollisionSDF::Resolution GPUParticlesCollisionSDF::get_resolution() const {
+	return resolution;
+}
+
+void GPUParticlesCollisionSDF::set_texture(const Ref<Texture3D> &p_texture) {
+	texture = p_texture;
+	RID tex = texture.is_valid() ? texture->get_rid() : RID();
+	RS::get_singleton()->particles_collision_set_field_texture(_get_collision(), tex);
+}
+
+Ref<Texture3D> GPUParticlesCollisionSDF::get_texture() const {
+	return texture;
+}
+
+AABB GPUParticlesCollisionSDF::get_aabb() const {
+	return AABB(-extents, extents * 2);
+}
+
+GPUParticlesCollisionSDF::BakeBeginFunc GPUParticlesCollisionSDF::bake_begin_function = nullptr;
+GPUParticlesCollisionSDF::BakeStepFunc GPUParticlesCollisionSDF::bake_step_function = nullptr;
+GPUParticlesCollisionSDF::BakeEndFunc GPUParticlesCollisionSDF::bake_end_function = nullptr;
+
+GPUParticlesCollisionSDF::GPUParticlesCollisionSDF() :
+		GPUParticlesCollision3D(RS::PARTICLES_COLLISION_TYPE_SDF_COLLIDE) {
+}
+
+GPUParticlesCollisionSDF::~GPUParticlesCollisionSDF() {
+}
+
+////////////////////////////
+////////////////////////////
+
+void GPUParticlesCollisionHeightField::_notification(int p_what) {
+	if (p_what == NOTIFICATION_INTERNAL_PROCESS) {
+		if (update_mode == UPDATE_MODE_ALWAYS) {
+			RS::get_singleton()->particles_collision_height_field_update(_get_collision());
+		}
+
+		if (follow_camera_mode && get_viewport()) {
+			Camera3D *cam = get_viewport()->get_camera();
+			if (cam) {
+				Transform xform = get_global_transform();
+				Vector3 x_axis = xform.basis.get_axis(Vector3::AXIS_X).normalized();
+				Vector3 z_axis = xform.basis.get_axis(Vector3::AXIS_Z).normalized();
+				float x_len = xform.basis.get_scale().x;
+				float z_len = xform.basis.get_scale().z;
+
+				Vector3 cam_pos = cam->get_global_transform().origin;
+				Transform new_xform = xform;
+
+				while (x_axis.dot(cam_pos - new_xform.origin) > x_len) {
+					new_xform.origin += x_axis * x_len;
+				}
+				while (x_axis.dot(cam_pos - new_xform.origin) < -x_len) {
+					new_xform.origin -= x_axis * x_len;
+				}
+
+				while (z_axis.dot(cam_pos - new_xform.origin) > z_len) {
+					new_xform.origin += z_axis * z_len;
+				}
+				while (z_axis.dot(cam_pos - new_xform.origin) < -z_len) {
+					new_xform.origin -= z_axis * z_len;
+				}
+
+				if (new_xform != xform) {
+					set_global_transform(new_xform);
+					RS::get_singleton()->particles_collision_height_field_update(_get_collision());
+				}
+			}
+		}
+	}
+
+	if (p_what == NOTIFICATION_TRANSFORM_CHANGED) {
+		RS::get_singleton()->particles_collision_height_field_update(_get_collision());
+	}
+}
+
+void GPUParticlesCollisionHeightField::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_extents", "extents"), &GPUParticlesCollisionHeightField::set_extents);
+	ClassDB::bind_method(D_METHOD("get_extents"), &GPUParticlesCollisionHeightField::get_extents);
+
+	ClassDB::bind_method(D_METHOD("set_resolution", "resolution"), &GPUParticlesCollisionHeightField::set_resolution);
+	ClassDB::bind_method(D_METHOD("get_resolution"), &GPUParticlesCollisionHeightField::get_resolution);
+
+	ClassDB::bind_method(D_METHOD("set_update_mode", "update_mode"), &GPUParticlesCollisionHeightField::set_update_mode);
+	ClassDB::bind_method(D_METHOD("get_update_mode"), &GPUParticlesCollisionHeightField::get_update_mode);
+
+	ClassDB::bind_method(D_METHOD("set_follow_camera_mode", "enabled"), &GPUParticlesCollisionHeightField::set_follow_camera_mode);
+	ClassDB::bind_method(D_METHOD("is_follow_camera_mode_enabled"), &GPUParticlesCollisionHeightField::is_follow_camera_mode_enabled);
+
+	ClassDB::bind_method(D_METHOD("set_follow_camera_push_ratio", "ratio"), &GPUParticlesCollisionHeightField::set_follow_camera_push_ratio);
+	ClassDB::bind_method(D_METHOD("get_follow_camera_push_ratio"), &GPUParticlesCollisionHeightField::get_follow_camera_push_ratio);
+
+	ADD_PROPERTY(PropertyInfo(Variant::VECTOR3, "extents", PROPERTY_HINT_RANGE, "0.01,1024,0.01,or_greater"), "set_extents", "get_extents");
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "resolution", PROPERTY_HINT_ENUM, "256,512,1024,2048,4096,8192"), "set_resolution", "get_resolution");
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "update_mode", PROPERTY_HINT_ENUM, "WhenMoved,Always"), "set_update_mode", "get_update_mode");
+	ADD_GROUP("Folow Camera", "follow_camera_");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "follow_camera_enabled"), "set_follow_camera_mode", "is_follow_camera_mode_enabled");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "follow_camera_push_ratio", PROPERTY_HINT_RANGE, "0.01,1,0.01"), "set_follow_camera_push_ratio", "get_follow_camera_push_ratio");
+
+	BIND_ENUM_CONSTANT(RESOLUTION_256);
+	BIND_ENUM_CONSTANT(RESOLUTION_512);
+	BIND_ENUM_CONSTANT(RESOLUTION_1024);
+	BIND_ENUM_CONSTANT(RESOLUTION_2048);
+	BIND_ENUM_CONSTANT(RESOLUTION_4096);
+	BIND_ENUM_CONSTANT(RESOLUTION_8192);
+	BIND_ENUM_CONSTANT(RESOLUTION_MAX);
+}
+
+void GPUParticlesCollisionHeightField::set_follow_camera_push_ratio(float p_follow_camera_push_ratio) {
+	follow_camera_push_ratio = p_follow_camera_push_ratio;
+}
+
+float GPUParticlesCollisionHeightField::get_follow_camera_push_ratio() const {
+	return follow_camera_push_ratio;
+}
+
+void GPUParticlesCollisionHeightField::set_extents(const Vector3 &p_extents) {
+	extents = p_extents;
+	RS::get_singleton()->particles_collision_set_box_extents(_get_collision(), extents);
+	update_gizmo();
+	RS::get_singleton()->particles_collision_height_field_update(_get_collision());
+}
+
+Vector3 GPUParticlesCollisionHeightField::get_extents() const {
+	return extents;
+}
+
+void GPUParticlesCollisionHeightField::set_resolution(Resolution p_resolution) {
+	resolution = p_resolution;
+	RS::get_singleton()->particles_collision_set_height_field_resolution(_get_collision(), RS::ParticlesCollisionHeightfieldResolution(resolution));
+	update_gizmo();
+	RS::get_singleton()->particles_collision_height_field_update(_get_collision());
+}
+
+GPUParticlesCollisionHeightField::Resolution GPUParticlesCollisionHeightField::get_resolution() const {
+	return resolution;
+}
+
+void GPUParticlesCollisionHeightField::set_update_mode(UpdateMode p_update_mode) {
+	update_mode = p_update_mode;
+	set_process_internal(follow_camera_mode || update_mode == UPDATE_MODE_ALWAYS);
+}
+
+GPUParticlesCollisionHeightField::UpdateMode GPUParticlesCollisionHeightField::get_update_mode() const {
+	return update_mode;
+}
+
+void GPUParticlesCollisionHeightField::set_follow_camera_mode(bool p_enabled) {
+	follow_camera_mode = p_enabled;
+	set_process_internal(follow_camera_mode || update_mode == UPDATE_MODE_ALWAYS);
+}
+
+bool GPUParticlesCollisionHeightField::is_follow_camera_mode_enabled() const {
+	return follow_camera_mode;
+}
+
+AABB GPUParticlesCollisionHeightField::get_aabb() const {
+	return AABB(-extents, extents * 2);
+}
+
+GPUParticlesCollisionHeightField::GPUParticlesCollisionHeightField() :
+		GPUParticlesCollision3D(RS::PARTICLES_COLLISION_TYPE_HEIGHTFIELD_COLLIDE) {
+}
+
+GPUParticlesCollisionHeightField::~GPUParticlesCollisionHeightField() {
+}
+
+////////////////////////////
+////////////////////////////
+
+void GPUParticlesAttractor3D::set_cull_mask(uint32_t p_cull_mask) {
+	cull_mask = p_cull_mask;
+	RS::get_singleton()->particles_collision_set_cull_mask(collision, p_cull_mask);
+}
+
+uint32_t GPUParticlesAttractor3D::get_cull_mask() const {
+	return cull_mask;
+}
+
+void GPUParticlesAttractor3D::set_strength(float p_strength) {
+	strength = p_strength;
+	RS::get_singleton()->particles_collision_set_attractor_strength(collision, p_strength);
+}
+
+float GPUParticlesAttractor3D::get_strength() const {
+	return strength;
+}
+
+void GPUParticlesAttractor3D::set_attenuation(float p_attenuation) {
+	attenuation = p_attenuation;
+	RS::get_singleton()->particles_collision_set_attractor_attenuation(collision, p_attenuation);
+}
+
+float GPUParticlesAttractor3D::get_attenuation() const {
+	return attenuation;
+}
+
+void GPUParticlesAttractor3D::set_directionality(float p_directionality) {
+	directionality = p_directionality;
+	RS::get_singleton()->particles_collision_set_attractor_directionality(collision, p_directionality);
+	update_gizmo();
+}
+
+float GPUParticlesAttractor3D::get_directionality() const {
+	return directionality;
+}
+
+void GPUParticlesAttractor3D::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_cull_mask", "mask"), &GPUParticlesAttractor3D::set_cull_mask);
+	ClassDB::bind_method(D_METHOD("get_cull_mask"), &GPUParticlesAttractor3D::get_cull_mask);
+
+	ClassDB::bind_method(D_METHOD("set_strength", "strength"), &GPUParticlesAttractor3D::set_strength);
+	ClassDB::bind_method(D_METHOD("get_strength"), &GPUParticlesAttractor3D::get_strength);
+
+	ClassDB::bind_method(D_METHOD("set_attenuation", "attenuation"), &GPUParticlesAttractor3D::set_attenuation);
+	ClassDB::bind_method(D_METHOD("get_attenuation"), &GPUParticlesAttractor3D::get_attenuation);
+
+	ClassDB::bind_method(D_METHOD("set_directionality", "amount"), &GPUParticlesAttractor3D::set_directionality);
+	ClassDB::bind_method(D_METHOD("get_directionality"), &GPUParticlesAttractor3D::get_directionality);
+
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "strength", PROPERTY_HINT_RANGE, "-128,128,0.01,or_greater,or_lesser"), "set_strength", "get_strength");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "attenuation", PROPERTY_HINT_EXP_EASING, "0,8,0.01"), "set_attenuation", "get_attenuation");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "directionality", PROPERTY_HINT_RANGE, "0,1,0.01"), "set_directionality", "get_directionality");
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "cull_mask", PROPERTY_HINT_LAYERS_3D_RENDER), "set_cull_mask", "get_cull_mask");
+}
+
+GPUParticlesAttractor3D::GPUParticlesAttractor3D(RS::ParticlesCollisionType p_type) {
+	collision = RS::get_singleton()->particles_collision_create();
+	RS::get_singleton()->particles_collision_set_collision_type(collision, p_type);
+	set_base(collision);
+}
+GPUParticlesAttractor3D::~GPUParticlesAttractor3D() {
+	RS::get_singleton()->free(collision);
+}
+
+/////////////////////////////////
+
+void GPUParticlesAttractorSphere::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_radius", "radius"), &GPUParticlesAttractorSphere::set_radius);
+	ClassDB::bind_method(D_METHOD("get_radius"), &GPUParticlesAttractorSphere::get_radius);
+
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "radius", PROPERTY_HINT_RANGE, "0.01,1024,0.01,or_greater"), "set_radius", "get_radius");
+}
+
+void GPUParticlesAttractorSphere::set_radius(float p_radius) {
+	radius = p_radius;
+	RS::get_singleton()->particles_collision_set_sphere_radius(_get_collision(), radius);
+	update_gizmo();
+}
+
+float GPUParticlesAttractorSphere::get_radius() const {
+	return radius;
+}
+
+AABB GPUParticlesAttractorSphere::get_aabb() const {
+	return AABB(Vector3(-radius, -radius, -radius), Vector3(radius * 2, radius * 2, radius * 2));
+}
+
+GPUParticlesAttractorSphere::GPUParticlesAttractorSphere() :
+		GPUParticlesAttractor3D(RS::PARTICLES_COLLISION_TYPE_SPHERE_ATTRACT) {
+}
+
+GPUParticlesAttractorSphere::~GPUParticlesAttractorSphere() {
+}
+
+///////////////////////////
+
+void GPUParticlesAttractorBox::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_extents", "extents"), &GPUParticlesAttractorBox::set_extents);
+	ClassDB::bind_method(D_METHOD("get_extents"), &GPUParticlesAttractorBox::get_extents);
+
+	ADD_PROPERTY(PropertyInfo(Variant::VECTOR3, "extents", PROPERTY_HINT_RANGE, "0.01,1024,0.01,or_greater"), "set_extents", "get_extents");
+}
+
+void GPUParticlesAttractorBox::set_extents(const Vector3 &p_extents) {
+	extents = p_extents;
+	RS::get_singleton()->particles_collision_set_box_extents(_get_collision(), extents);
+	update_gizmo();
+}
+
+Vector3 GPUParticlesAttractorBox::get_extents() const {
+	return extents;
+}
+
+AABB GPUParticlesAttractorBox::get_aabb() const {
+	return AABB(-extents, extents * 2);
+}
+
+GPUParticlesAttractorBox::GPUParticlesAttractorBox() :
+		GPUParticlesAttractor3D(RS::PARTICLES_COLLISION_TYPE_BOX_ATTRACT) {
+}
+
+GPUParticlesAttractorBox::~GPUParticlesAttractorBox() {
+}
+
+///////////////////////////
+
+void GPUParticlesAttractorVectorField::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_extents", "extents"), &GPUParticlesAttractorVectorField::set_extents);
+	ClassDB::bind_method(D_METHOD("get_extents"), &GPUParticlesAttractorVectorField::get_extents);
+
+	ClassDB::bind_method(D_METHOD("set_texture", "texture"), &GPUParticlesAttractorVectorField::set_texture);
+	ClassDB::bind_method(D_METHOD("get_texture"), &GPUParticlesAttractorVectorField::get_texture);
+
+	ADD_PROPERTY(PropertyInfo(Variant::VECTOR3, "extents", PROPERTY_HINT_RANGE, "0.01,1024,0.01,or_greater"), "set_extents", "get_extents");
+	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "texture", PROPERTY_HINT_RESOURCE_TYPE, "Texture3D"), "set_texture", "get_texture");
+}
+
+void GPUParticlesAttractorVectorField::set_extents(const Vector3 &p_extents) {
+	extents = p_extents;
+	RS::get_singleton()->particles_collision_set_box_extents(_get_collision(), extents);
+	update_gizmo();
+}
+
+Vector3 GPUParticlesAttractorVectorField::get_extents() const {
+	return extents;
+}
+
+void GPUParticlesAttractorVectorField::set_texture(const Ref<Texture3D> &p_texture) {
+	texture = p_texture;
+	RID tex = texture.is_valid() ? texture->get_rid() : RID();
+	RS::get_singleton()->particles_collision_set_field_texture(_get_collision(), tex);
+}
+
+Ref<Texture3D> GPUParticlesAttractorVectorField::get_texture() const {
+	return texture;
+}
+
+AABB GPUParticlesAttractorVectorField::get_aabb() const {
+	return AABB(-extents, extents * 2);
+}
+
+GPUParticlesAttractorVectorField::GPUParticlesAttractorVectorField() :
+		GPUParticlesAttractor3D(RS::PARTICLES_COLLISION_TYPE_VECTOR_FIELD_ATTRACT) {
+}
+
+GPUParticlesAttractorVectorField::~GPUParticlesAttractorVectorField() {
+}

scene/3d/gpu_particles_collision_3d.h

@@ -0,0 +1,342 @@
+/*************************************************************************/
+/*  gpu_particles_collision_3d.h                                         */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef GPU_PARTICLES_COLLISION_3D_H
+#define GPU_PARTICLES_COLLISION_3D_H
+
+#include "core/local_vector.h"
+#include "core/rid.h"
+#include "scene/3d/visual_instance_3d.h"
+#include "scene/resources/material.h"
+
+class GPUParticlesCollision3D : public VisualInstance3D {
+	GDCLASS(GPUParticlesCollision3D, VisualInstance3D);
+
+	uint32_t cull_mask = 0xFFFFFFFF;
+	RID collision;
+
+protected:
+	_FORCE_INLINE_ RID _get_collision() { return collision; }
+	static void _bind_methods();
+
+	GPUParticlesCollision3D(RS::ParticlesCollisionType p_type);
+
+public:
+	void set_cull_mask(uint32_t p_cull_mask);
+	uint32_t get_cull_mask() const;
+
+	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override { return Vector<Face3>(); }
+
+	~GPUParticlesCollision3D();
+};
+
+class GPUParticlesCollisionSphere : public GPUParticlesCollision3D {
+	GDCLASS(GPUParticlesCollisionSphere, GPUParticlesCollision3D);
+
+	float radius = 1.0;
+
+protected:
+	static void _bind_methods();
+
+public:
+	void set_radius(float p_radius);
+	float get_radius() const;
+
+	virtual AABB get_aabb() const override;
+
+	GPUParticlesCollisionSphere();
+	~GPUParticlesCollisionSphere();
+};
+
+class GPUParticlesCollisionBox : public GPUParticlesCollision3D {
+	GDCLASS(GPUParticlesCollisionBox, GPUParticlesCollision3D);
+
+	Vector3 extents = Vector3(1, 1, 1);
+
+protected:
+	static void _bind_methods();
+
+public:
+	void set_extents(const Vector3 &p_extents);
+	Vector3 get_extents() const;
+
+	virtual AABB get_aabb() const override;
+
+	GPUParticlesCollisionBox();
+	~GPUParticlesCollisionBox();
+};
+
+class GPUParticlesCollisionSDF : public GPUParticlesCollision3D {
+	GDCLASS(GPUParticlesCollisionSDF, GPUParticlesCollision3D);
+
+public:
+	enum Resolution {
+		RESOLUTION_16,
+		RESOLUTION_32,
+		RESOLUTION_64,
+		RESOLUTION_128,
+		RESOLUTION_256,
+		RESOLUTION_512,
+		RESOLUTION_MAX,
+	};
+
+	typedef void (*BakeBeginFunc)(int);
+	typedef void (*BakeStepFunc)(int, const String &);
+	typedef void (*BakeEndFunc)();
+
+private:
+	Vector3 extents = Vector3(1, 1, 1);
+	Resolution resolution = RESOLUTION_64;
+	Ref<Texture3D> texture;
+	float thickness = 1.0;
+
+	struct PlotMesh {
+		Ref<Mesh> mesh;
+		Transform local_xform;
+	};
+
+	void _find_meshes(const AABB &p_aabb, Node *p_at_node, List<PlotMesh> &plot_meshes);
+
+	struct BVH {
+		enum {
+			LEAF_BIT = 1 << 30,
+			LEAF_MASK = LEAF_BIT - 1
+		};
+		AABB bounds;
+		uint32_t children[2];
+	};
+
+	struct FacePos {
+		Vector3 center;
+		uint32_t index;
+	};
+
+	struct FaceSort {
+		uint32_t axis;
+		bool operator()(const FacePos &p_left, const FacePos &p_right) const {
+			return p_left.center[axis] < p_right.center[axis];
+		}
+	};
+
+	uint32_t _create_bvh(LocalVector<BVH> &bvh_tree, FacePos *p_faces, uint32_t p_face_count, const Face3 *p_triangles, float p_thickness);
+
+	struct ComputeSDFParams {
+		float *cells;
+		Vector3i size;
+		float cell_size;
+		Vector3 cell_offset;
+		const BVH *bvh;
+		const Face3 *triangles;
+		float thickness;
+	};
+
+	void _find_closest_distance(const Vector3 &p_pos, const BVH *bvh, uint32_t p_bvh_cell, const Face3 *triangles, float thickness, float &closest_distance);
+	void _compute_sdf_z(uint32_t p_z, ComputeSDFParams *params);
+	void _compute_sdf(ComputeSDFParams *params);
+
+protected:
+	static void _bind_methods();
+
+public:
+	void set_thickness(float p_thickness);
+	float get_thickness() const;
+
+	void set_extents(const Vector3 &p_extents);
+	Vector3 get_extents() const;
+
+	void set_resolution(Resolution p_resolution);
+	Resolution get_resolution() const;
+
+	void set_texture(const Ref<Texture3D> &p_texture);
+	Ref<Texture3D> get_texture() const;
+
+	Vector3i get_estimated_cell_size() const;
+	Ref<Image> bake();
+
+	virtual AABB get_aabb() const override;
+
+	static BakeBeginFunc bake_begin_function;
+	static BakeStepFunc bake_step_function;
+	static BakeEndFunc bake_end_function;
+
+	GPUParticlesCollisionSDF();
+	~GPUParticlesCollisionSDF();
+};
+
+VARIANT_ENUM_CAST(GPUParticlesCollisionSDF::Resolution)
+
+class GPUParticlesCollisionHeightField : public GPUParticlesCollision3D {
+	GDCLASS(GPUParticlesCollisionHeightField, GPUParticlesCollision3D);
+
+public:
+	enum Resolution {
+		RESOLUTION_256,
+		RESOLUTION_512,
+		RESOLUTION_1024,
+		RESOLUTION_2048,
+		RESOLUTION_4096,
+		RESOLUTION_8192,
+		RESOLUTION_MAX,
+	};
+
+	enum UpdateMode {
+		UPDATE_MODE_WHEN_MOVED,
+		UPDATE_MODE_ALWAYS,
+	};
+
+private:
+	Vector3 extents = Vector3(1, 1, 1);
+	Resolution resolution = RESOLUTION_1024;
+	bool follow_camera_mode = false;
+	float follow_camera_push_ratio = 0.1;
+
+	UpdateMode update_mode = UPDATE_MODE_WHEN_MOVED;
+
+protected:
+	void _notification(int p_what);
+	static void _bind_methods();
+
+public:
+	void set_extents(const Vector3 &p_extents);
+	Vector3 get_extents() const;
+
+	void set_resolution(Resolution p_resolution);
+	Resolution get_resolution() const;
+
+	void set_update_mode(UpdateMode p_update_mode);
+	UpdateMode get_update_mode() const;
+
+	void set_follow_camera_mode(bool p_enabled);
+	bool is_follow_camera_mode_enabled() const;
+
+	void set_follow_camera_push_ratio(float p_ratio);
+	float get_follow_camera_push_ratio() const;
+
+	virtual AABB get_aabb() const override;
+
+	GPUParticlesCollisionHeightField();
+	~GPUParticlesCollisionHeightField();
+};
+
+VARIANT_ENUM_CAST(GPUParticlesCollisionHeightField::Resolution)
+VARIANT_ENUM_CAST(GPUParticlesCollisionHeightField::UpdateMode)
+
+class GPUParticlesAttractor3D : public VisualInstance3D {
+	GDCLASS(GPUParticlesAttractor3D, VisualInstance3D);
+
+	uint32_t cull_mask = 0xFFFFFFFF;
+	RID collision;
+	float strength = 1.0;
+	float attenuation = 1.0;
+	float directionality = 0.0;
+
+protected:
+	_FORCE_INLINE_ RID _get_collision() { return collision; }
+	static void _bind_methods();
+
+	GPUParticlesAttractor3D(RS::ParticlesCollisionType p_type);
+
+public:
+	void set_cull_mask(uint32_t p_cull_mask);
+	uint32_t get_cull_mask() const;
+
+	void set_strength(float p_strength);
+	float get_strength() const;
+
+	void set_attenuation(float p_attenuation);
+	float get_attenuation() const;
+
+	void set_directionality(float p_directionality);
+	float get_directionality() const;
+
+	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override { return Vector<Face3>(); }
+
+	~GPUParticlesAttractor3D();
+};
+
+class GPUParticlesAttractorSphere : public GPUParticlesAttractor3D {
+	GDCLASS(GPUParticlesAttractorSphere, GPUParticlesAttractor3D);
+
+	float radius = 1.0;
+
+protected:
+	static void _bind_methods();
+
+public:
+	void set_radius(float p_radius);
+	float get_radius() const;
+
+	virtual AABB get_aabb() const override;
+
+	GPUParticlesAttractorSphere();
+	~GPUParticlesAttractorSphere();
+};
+
+class GPUParticlesAttractorBox : public GPUParticlesAttractor3D {
+	GDCLASS(GPUParticlesAttractorBox, GPUParticlesAttractor3D);
+
+	Vector3 extents = Vector3(1, 1, 1);
+
+protected:
+	static void _bind_methods();
+
+public:
+	void set_extents(const Vector3 &p_extents);
+	Vector3 get_extents() const;
+
+	virtual AABB get_aabb() const override;
+
+	GPUParticlesAttractorBox();
+	~GPUParticlesAttractorBox();
+};
+
+class GPUParticlesAttractorVectorField : public GPUParticlesAttractor3D {
+	GDCLASS(GPUParticlesAttractorVectorField, GPUParticlesAttractor3D);
+
+	Vector3 extents = Vector3(1, 1, 1);
+	Ref<Texture3D> texture;
+
+protected:
+	static void _bind_methods();
+
+public:
+	void set_extents(const Vector3 &p_extents);
+	Vector3 get_extents() const;
+
+	void set_texture(const Ref<Texture3D> &p_texture);
+	Ref<Texture3D> get_texture() const;
+
+	virtual AABB get_aabb() const override;
+
+	GPUParticlesAttractorVectorField();
+	~GPUParticlesAttractorVectorField();
+};
+
+#endif // GPU_PARTICLES_COLLISION_3D_H

scene/register_scene_types.cpp

@@ -194,6 +194,7 @@
 #include "scene/3d/decal.h"
 #include "scene/3d/gi_probe.h"
 #include "scene/3d/gpu_particles_3d.h"
+#include "scene/3d/gpu_particles_collision_3d.h"
 #include "scene/3d/immediate_geometry_3d.h"
 #include "scene/3d/light_3d.h"
 #include "scene/3d/lightmap_probe.h"
@@ -450,6 +451,15 @@ void register_scene_types() {
 	ClassDB::register_class<LightmapProbe>();
 	ClassDB::register_virtual_class<Lightmapper>();
 	ClassDB::register_class<GPUParticles3D>();
+	ClassDB::register_virtual_class<GPUParticlesCollision3D>();
+	ClassDB::register_class<GPUParticlesCollisionBox>();
+	ClassDB::register_class<GPUParticlesCollisionSphere>();
+	ClassDB::register_class<GPUParticlesCollisionSDF>();
+	ClassDB::register_class<GPUParticlesCollisionHeightField>();
+	ClassDB::register_virtual_class<GPUParticlesAttractor3D>();
+	ClassDB::register_class<GPUParticlesAttractorBox>();
+	ClassDB::register_class<GPUParticlesAttractorSphere>();
+	ClassDB::register_class<GPUParticlesAttractorVectorField>();
 	ClassDB::register_class<CPUParticles3D>();
 	ClassDB::register_class<Position3D>();
 

scene/resources/particles_material.cpp

@@ -98,6 +98,9 @@ void ParticlesMaterial::init_shaders() {
 	shader_names->sub_emitter_frequency = "sub_emitter_frequency";
 	shader_names->sub_emitter_amount_at_end = "sub_emitter_amount_at_end";
 	shader_names->sub_emitter_keep_velocity = "sub_emitter_keep_velocity";
+
+	shader_names->collision_friction = "collision_friction";
+	shader_names->collision_bounce = "collision_bounce";
 }
 
 void ParticlesMaterial::finish_shaders() {
@@ -136,6 +139,10 @@ void ParticlesMaterial::_update_shader() {
 
 	String code = "shader_type particles;\n";
 
+	if (collision_scale) {
+		code += "render_mode collision_use_scale;\n";
+	}
+
 	code += "uniform vec3 direction;\n";
 	code += "uniform float spread;\n";
 	code += "uniform float flatness;\n";
@@ -247,6 +254,11 @@ void ParticlesMaterial::_update_shader() {
 		code += "uniform sampler2D anim_offset_texture;\n";
 	}
 
+	if (collision_enabled) {
+		code += "uniform float collision_friction;\n";
+		code += "uniform float collision_bounce;\n";
+	}
+
 	//need a random function
 	code += "\n\n";
 	code += "float rand_from_seed(inout uint seed) {\n";
@@ -476,6 +488,10 @@ void ParticlesMaterial::_update_shader() {
 		code += "		vec3 crossDiff = cross(normalize(diff), normalize(gravity));\n";
 		code += "		force += length(crossDiff) > 0.0 ? normalize(crossDiff) * ((tangent_accel + tex_tangent_accel) * mix(1.0, rand_from_seed(alt_seed), tangent_accel_random)) : vec3(0.0);\n";
 	}
+	if (attractor_interaction_enabled) {
+		code += "		force += ATTRACTOR_FORCE;\n\n";
+	}
+
 	code += "		// apply attractor forces\n";
 	code += "		VELOCITY += force * DELTA;\n";
 	code += "		// orbit velocity\n";
@@ -599,6 +615,13 @@ void ParticlesMaterial::_update_shader() {
 		code += "	VELOCITY.z = 0.0;\n";
 		code += "	TRANSFORM[3].z = 0.0;\n";
 	}
+	if (collision_enabled) {
+		code += "	if (COLLIDED) {\n";
+		code += "		TRANSFORM[3].xyz+=COLLISION_NORMAL * COLLISION_DEPTH;\n";
+		code += "		VELOCITY -= COLLISION_NORMAL * dot(COLLISION_NORMAL, VELOCITY) * (1.0 + collision_bounce);\n";
+		code += "		VELOCITY = mix(VELOCITY,vec3(0.0),collision_friction * DELTA * 100.0);\n";
+		code += "	}\n";
+	}
 	if (sub_emitter_mode != SUB_EMITTER_DISABLED) {
 		code += "	int emit_count = 0;\n";
 		switch (sub_emitter_mode) {
@@ -609,6 +632,7 @@ void ParticlesMaterial::_update_shader() {
 			} break;
 			case SUB_EMITTER_AT_COLLISION: {
 				//not implemented yet
+				code += "	if (COLLIDED) emit_count = 1;\n";
 			} break;
 			case SUB_EMITTER_AT_END: {
 				//not implemented yet
@@ -1072,6 +1096,51 @@ bool ParticlesMaterial::get_sub_emitter_keep_velocity() const {
 	return sub_emitter_keep_velocity;
 }
 
+void ParticlesMaterial::set_attractor_interaction_enabled(bool p_enable) {
+	attractor_interaction_enabled = p_enable;
+	_queue_shader_change();
+}
+
+bool ParticlesMaterial::is_attractor_interaction_enabled() const {
+	return attractor_interaction_enabled;
+}
+
+void ParticlesMaterial::set_collision_enabled(bool p_enabled) {
+	collision_enabled = p_enabled;
+	_queue_shader_change();
+}
+
+bool ParticlesMaterial::is_collision_enabled() const {
+	return collision_enabled;
+}
+
+void ParticlesMaterial::set_collision_use_scale(bool p_scale) {
+	collision_scale = p_scale;
+	_queue_shader_change();
+}
+
+bool ParticlesMaterial::is_collision_using_scale() const {
+	return collision_scale;
+}
+
+void ParticlesMaterial::set_collision_friction(float p_friction) {
+	collision_friction = p_friction;
+	RenderingServer::get_singleton()->material_set_param(_get_material(), shader_names->collision_friction, p_friction);
+}
+
+float ParticlesMaterial::get_collision_friction() const {
+	return collision_friction;
+}
+
+void ParticlesMaterial::set_collision_bounce(float p_bounce) {
+	collision_bounce = p_bounce;
+	RenderingServer::get_singleton()->material_set_param(_get_material(), shader_names->collision_bounce, p_bounce);
+}
+
+float ParticlesMaterial::get_collision_bounce() const {
+	return collision_bounce;
+}
+
 Shader::Mode ParticlesMaterial::get_shader_mode() const {
 	return Shader::MODE_PARTICLES;
 }
@@ -1143,6 +1212,21 @@ void ParticlesMaterial::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_sub_emitter_keep_velocity"), &ParticlesMaterial::get_sub_emitter_keep_velocity);
 	ClassDB::bind_method(D_METHOD("set_sub_emitter_keep_velocity", "enable"), &ParticlesMaterial::set_sub_emitter_keep_velocity);
 
+	ClassDB::bind_method(D_METHOD("set_attractor_interaction_enabled", "enabled"), &ParticlesMaterial::set_attractor_interaction_enabled);
+	ClassDB::bind_method(D_METHOD("is_attractor_interaction_enabled"), &ParticlesMaterial::is_attractor_interaction_enabled);
+
+	ClassDB::bind_method(D_METHOD("set_collision_enabled", "enabled"), &ParticlesMaterial::set_collision_enabled);
+	ClassDB::bind_method(D_METHOD("is_collision_enabled"), &ParticlesMaterial::is_collision_enabled);
+
+	ClassDB::bind_method(D_METHOD("set_collision_use_scale", "radius"), &ParticlesMaterial::set_collision_use_scale);
+	ClassDB::bind_method(D_METHOD("is_collision_using_scale"), &ParticlesMaterial::is_collision_using_scale);
+
+	ClassDB::bind_method(D_METHOD("set_collision_friction", "friction"), &ParticlesMaterial::set_collision_friction);
+	ClassDB::bind_method(D_METHOD("get_collision_friction"), &ParticlesMaterial::get_collision_friction);
+
+	ClassDB::bind_method(D_METHOD("set_collision_bounce", "bounce"), &ParticlesMaterial::set_collision_bounce);
+	ClassDB::bind_method(D_METHOD("get_collision_bounce"), &ParticlesMaterial::get_collision_bounce);
+
 	ADD_GROUP("Time", "");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "lifetime_randomness", PROPERTY_HINT_RANGE, "0,1,0.01"), "set_lifetime_randomness", "get_lifetime_randomness");
 
@@ -1221,6 +1305,14 @@ void ParticlesMaterial::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "sub_emitter_amount_at_end", PROPERTY_HINT_RANGE, "1,32,1"), "set_sub_emitter_amount_at_end", "get_sub_emitter_amount_at_end");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "sub_emitter_keep_velocity"), "set_sub_emitter_keep_velocity", "get_sub_emitter_keep_velocity");
 
+	ADD_GROUP("Attractor Interaction", "attractor_interaction_");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "attractor_interaction_enabled"), "set_attractor_interaction_enabled", "is_attractor_interaction_enabled");
+	ADD_GROUP("Collision", "collision_");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "collision_enabled"), "set_collision_enabled", "is_collision_enabled");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "collision_friction", PROPERTY_HINT_RANGE, "0,1,0.01"), "set_collision_friction", "get_collision_friction");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "collision_bounce", PROPERTY_HINT_RANGE, "0,1,0.01"), "set_collision_bounce", "get_collision_bounce");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "collision_use_scale"), "set_collision_use_scale", "is_collision_using_scale");
+
 	BIND_ENUM_CONSTANT(PARAM_INITIAL_LINEAR_VELOCITY);
 	BIND_ENUM_CONSTANT(PARAM_ANGULAR_VELOCITY);
 	BIND_ENUM_CONSTANT(PARAM_ORBIT_VELOCITY);
@@ -1283,6 +1375,12 @@ ParticlesMaterial::ParticlesMaterial() :
 	set_sub_emitter_amount_at_end(1);
 	set_sub_emitter_keep_velocity(false);
 
+	set_attractor_interaction_enabled(true);
+	set_collision_enabled(true);
+	set_collision_bounce(0.0);
+	set_collision_friction(0.0);
+	set_collision_use_scale(false);
+
 	for (int i = 0; i < PARAM_MAX; i++) {
 		set_param_randomness(Parameter(i), 0);
 	}

scene/resources/particles_material.h

@@ -37,11 +37,7 @@
 /*
  TODO:
 -Path following
-*Manual emission
--Sub Emitters
--Attractors
 -Emitter positions deformable by bones
--Collision
 -Proper trails
 */
 
@@ -99,6 +95,9 @@ private:
 			uint32_t invalid_key : 1;
 			uint32_t has_emission_color : 1;
 			uint32_t sub_emitter : 2;
+			uint32_t attractor_enabled : 1;
+			uint32_t collision_enabled : 1;
+			uint32_t collision_scale : 1;
 		};
 
 		uint32_t key;
@@ -135,6 +134,9 @@ private:
 		mk.emission_shape = emission_shape;
 		mk.has_emission_color = emission_shape >= EMISSION_SHAPE_POINTS && emission_color_texture.is_valid();
 		mk.sub_emitter = sub_emitter_mode;
+		mk.collision_enabled = collision_enabled;
+		mk.attractor_enabled = attractor_interaction_enabled;
+		mk.collision_scale = collision_scale;
 
 		return mk;
 	}
@@ -201,6 +203,9 @@ private:
 		StringName sub_emitter_frequency;
 		StringName sub_emitter_amount_at_end;
 		StringName sub_emitter_keep_velocity;
+
+		StringName collision_friction;
+		StringName collision_bounce;
 	};
 
 	static ShaderNames *shader_names;
@@ -244,6 +249,12 @@ private:
 	bool sub_emitter_keep_velocity;
 	//do not save emission points here
 
+	bool attractor_interaction_enabled;
+	bool collision_enabled;
+	bool collision_scale;
+	float collision_friction;
+	float collision_bounce;
+
 protected:
 	static void _bind_methods();
 	virtual void _validate_property(PropertyInfo &property) const override;
@@ -298,6 +309,21 @@ public:
 	void set_lifetime_randomness(float p_lifetime);
 	float get_lifetime_randomness() const;
 
+	void set_attractor_interaction_enabled(bool p_enable);
+	bool is_attractor_interaction_enabled() const;
+
+	void set_collision_enabled(bool p_enabled);
+	bool is_collision_enabled() const;
+
+	void set_collision_use_scale(bool p_scale);
+	bool is_collision_using_scale() const;
+
+	void set_collision_friction(float p_friction);
+	float get_collision_friction() const;
+
+	void set_collision_bounce(float p_bounce);
+	float get_collision_bounce() const;
+
 	static void init_shaders();
 	static void finish_shaders();
 	static void flush_changes();

servers/rendering/rasterizer.h

@@ -299,6 +299,7 @@ public:
 	virtual void render_material(const Transform &p_cam_transform, const CameraMatrix &p_cam_projection, bool p_cam_ortogonal, InstanceBase **p_cull_result, int p_cull_count, RID p_framebuffer, const Rect2i &p_region) = 0;
 	virtual void render_sdfgi(RID p_render_buffers, int p_region, InstanceBase **p_cull_result, int p_cull_count) = 0;
 	virtual void render_sdfgi_static_lights(RID p_render_buffers, uint32_t p_cascade_count, const uint32_t *p_cascade_indices, const RID **p_positional_light_cull_result, const uint32_t *p_positional_light_cull_count) = 0;
+	virtual void render_particle_collider_heightfield(RID p_collider, const Transform &p_transform, InstanceBase **p_cull_result, int p_cull_count) = 0;
 
 	virtual void set_scene_pass(uint64_t p_pass) = 0;
 	virtual void set_time(double p_time, double p_step) = 0;
@@ -660,6 +661,7 @@ public:
 	virtual void particles_set_process_material(RID p_particles, RID p_material) = 0;
 	virtual void particles_set_fixed_fps(RID p_particles, int p_fps) = 0;
 	virtual void particles_set_fractional_delta(RID p_particles, bool p_enable) = 0;
+	virtual void particles_set_collision_base_size(RID p_particles, float p_size) = 0;
 	virtual void particles_restart(RID p_particles) = 0;
 	virtual void particles_emit(RID p_particles, const Transform &p_transform, const Vector3 &p_velocity, const Color &p_color, const Color &p_custom, uint32_t p_emit_flags) = 0;
 	virtual void particles_set_subemitter(RID p_particles, RID p_subemitter_particles) = 0;
@@ -682,6 +684,28 @@ public:
 
 	virtual void particles_set_view_axis(RID p_particles, const Vector3 &p_axis) = 0;
 
+	virtual void particles_add_collision(RID p_particles, RasterizerScene::InstanceBase *p_instance) = 0;
+	virtual void particles_remove_collision(RID p_particles, RasterizerScene::InstanceBase *p_instance) = 0;
+
+	virtual void update_particles() = 0;
+
+	/* PARTICLES COLLISION */
+
+	virtual RID particles_collision_create() = 0;
+	virtual void particles_collision_set_collision_type(RID p_particles_collision, RS::ParticlesCollisionType p_type) = 0;
+	virtual void particles_collision_set_cull_mask(RID p_particles_collision, uint32_t p_cull_mask) = 0;
+	virtual void particles_collision_set_sphere_radius(RID p_particles_collision, float p_radius) = 0; //for spheres
+	virtual void particles_collision_set_box_extents(RID p_particles_collision, const Vector3 &p_extents) = 0; //for non-spheres
+	virtual void particles_collision_set_attractor_strength(RID p_particles_collision, float p_strength) = 0;
+	virtual void particles_collision_set_attractor_directionality(RID p_particles_collision, float p_directionality) = 0;
+	virtual void particles_collision_set_attractor_attenuation(RID p_particles_collision, float p_curve) = 0;
+	virtual void particles_collision_set_field_texture(RID p_particles_collision, RID p_texture) = 0; //for SDF and vector field, heightfield is dynamic
+	virtual void particles_collision_height_field_update(RID p_particles_collision) = 0; //for SDF and vector field
+	virtual void particles_collision_set_height_field_resolution(RID p_particles_collision, RS::ParticlesCollisionHeightfieldResolution p_resolution) = 0; //for SDF and vector field
+	virtual AABB particles_collision_get_aabb(RID p_particles_collision) const = 0;
+	virtual bool particles_collision_is_heightfield(RID p_particles_collision) const = 0;
+	virtual RID particles_collision_get_heightfield_framebuffer(RID p_particles_collision) const = 0;
+
 	/* GLOBAL VARIABLES */
 
 	virtual void global_variable_add(const StringName &p_name, RS::GlobalVariableType p_type, const Variant &p_value) = 0;

servers/rendering/rasterizer_rd/rasterizer_scene_high_end_rd.cpp

@@ -2018,6 +2018,39 @@ void RasterizerSceneHighEndRD::_render_shadow(RID p_framebuffer, InstanceBase **
 	}
 }
 
+void RasterizerSceneHighEndRD::_render_particle_collider_heightfield(RID p_fb, const Transform &p_cam_transform, const CameraMatrix &p_cam_projection, InstanceBase **p_cull_result, int p_cull_count) {
+	RENDER_TIMESTAMP("Setup Render Collider Heightfield");
+
+	_update_render_base_uniform_set();
+
+	render_pass++;
+
+	scene_state.ubo.dual_paraboloid_side = 0;
+
+	_setup_environment(RID(), RID(), p_cam_projection, p_cam_transform, RID(), true, Vector2(1, 1), RID(), true, Color(), 0, p_cam_projection.get_z_far(), false, false);
+
+	render_list.clear();
+
+	PassMode pass_mode = PASS_MODE_SHADOW;
+
+	_fill_render_list(p_cull_result, p_cull_count, pass_mode);
+
+	_setup_view_dependant_uniform_set(RID(), RID(), nullptr, 0);
+
+	RENDER_TIMESTAMP("Render Collider Heightield");
+
+	render_list.sort_by_key(false);
+
+	_fill_instances(render_list.elements, render_list.element_count, true);
+
+	{
+		//regular forward for now
+		RD::DrawListID draw_list = RD::get_singleton()->draw_list_begin(p_fb, RD::INITIAL_ACTION_CLEAR, RD::FINAL_ACTION_READ, RD::INITIAL_ACTION_CLEAR, RD::FINAL_ACTION_READ);
+		_render_list(draw_list, RD::get_singleton()->framebuffer_get_format(p_fb), render_list.elements, render_list.element_count, false, pass_mode, true, RID(), RID());
+		RD::get_singleton()->draw_list_end();
+	}
+}
+
 void RasterizerSceneHighEndRD::_render_material(const Transform &p_cam_transform, const CameraMatrix &p_cam_projection, bool p_cam_ortogonal, InstanceBase **p_cull_result, int p_cull_count, RID p_framebuffer, const Rect2i &p_region) {
 	RENDER_TIMESTAMP("Setup Rendering Material");
 

servers/rendering/rasterizer_rd/rasterizer_scene_high_end_rd.h

@@ -581,6 +581,7 @@ protected:
 	virtual void _render_material(const Transform &p_cam_transform, const CameraMatrix &p_cam_projection, bool p_cam_ortogonal, InstanceBase **p_cull_result, int p_cull_count, RID p_framebuffer, const Rect2i &p_region);
 	virtual void _render_uv2(InstanceBase **p_cull_result, int p_cull_count, RID p_framebuffer, const Rect2i &p_region);
 	virtual void _render_sdfgi(RID p_render_buffers, const Vector3i &p_from, const Vector3i &p_size, const AABB &p_bounds, InstanceBase **p_cull_result, int p_cull_count, const RID &p_albedo_texture, const RID &p_emission_texture, const RID &p_emission_aniso_texture, const RID &p_geom_facing_texture);
+	virtual void _render_particle_collider_heightfield(RID p_fb, const Transform &p_cam_transform, const CameraMatrix &p_cam_projection, InstanceBase **p_cull_result, int p_cull_count);
 
 public:
 	virtual void set_time(double p_time, double p_step);

servers/rendering/rasterizer_rd/rasterizer_scene_rd.cpp

@@ -7511,6 +7511,23 @@ void RasterizerSceneRD::render_sdfgi(RID p_render_buffers, int p_region, Instanc
 	}
 }
 
+void RasterizerSceneRD::render_particle_collider_heightfield(RID p_collider, const Transform &p_transform, InstanceBase **p_cull_result, int p_cull_count) {
+	ERR_FAIL_COND(!storage->particles_collision_is_heightfield(p_collider));
+	Vector3 extents = storage->particles_collision_get_extents(p_collider) * p_transform.basis.get_scale();
+	CameraMatrix cm;
+	cm.set_orthogonal(-extents.x, extents.x, -extents.z, extents.z, 0, extents.y * 2.0);
+
+	Vector3 cam_pos = p_transform.origin;
+	cam_pos.y += extents.y;
+
+	Transform cam_xform;
+	cam_xform.set_look_at(cam_pos, cam_pos - p_transform.basis.get_axis(Vector3::AXIS_Y), -p_transform.basis.get_axis(Vector3::AXIS_Z).normalized());
+
+	RID fb = storage->particles_collision_get_heightfield_framebuffer(p_collider);
+
+	_render_particle_collider_heightfield(fb, cam_xform, cm, p_cull_result, p_cull_count);
+}
+
 void RasterizerSceneRD::render_sdfgi_static_lights(RID p_render_buffers, uint32_t p_cascade_count, const uint32_t *p_cascade_indices, const RID **p_positional_light_cull_result, const uint32_t *p_positional_light_cull_count) {
 	RenderBuffers *rb = render_buffers_owner.getornull(p_render_buffers);
 	ERR_FAIL_COND(!rb);

servers/rendering/rasterizer_rd/rasterizer_scene_rd.h

@@ -112,6 +112,7 @@ protected:
 	virtual void _render_material(const Transform &p_cam_transform, const CameraMatrix &p_cam_projection, bool p_cam_ortogonal, InstanceBase **p_cull_result, int p_cull_count, RID p_framebuffer, const Rect2i &p_region) = 0;
 	virtual void _render_uv2(InstanceBase **p_cull_result, int p_cull_count, RID p_framebuffer, const Rect2i &p_region) = 0;
 	virtual void _render_sdfgi(RID p_render_buffers, const Vector3i &p_from, const Vector3i &p_size, const AABB &p_bounds, InstanceBase **p_cull_result, int p_cull_count, const RID &p_albedo_texture, const RID &p_emission_texture, const RID &p_emission_aniso_texture, const RID &p_geom_facing_texture) = 0;
+	virtual void _render_particle_collider_heightfield(RID p_fb, const Transform &p_cam_transform, const CameraMatrix &p_cam_projection, InstanceBase **p_cull_result, int p_cull_count) = 0;
 
 	virtual void _debug_giprobe(RID p_gi_probe, RenderingDevice::DrawListID p_draw_list, RID p_framebuffer, const CameraMatrix &p_camera_with_transform, bool p_lighting, bool p_emission, float p_alpha);
 	void _debug_sdfgi_probes(RID p_render_buffers, RD::DrawListID p_draw_list, RID p_framebuffer, const CameraMatrix &p_camera_with_transform);
@@ -1876,6 +1877,8 @@ public:
 	void render_sdfgi(RID p_render_buffers, int p_region, InstanceBase **p_cull_result, int p_cull_count);
 	void render_sdfgi_static_lights(RID p_render_buffers, uint32_t p_cascade_count, const uint32_t *p_cascade_indices, const RID **p_positional_light_cull_result, const uint32_t *p_positional_light_cull_count);
 
+	void render_particle_collider_heightfield(RID p_collider, const Transform &p_transform, InstanceBase **p_cull_result, int p_cull_count);
+
 	virtual void set_scene_pass(uint64_t p_pass) {
 		scene_pass = p_pass;
 	}

servers/rendering/rasterizer_rd/rasterizer_storage_rd.cpp

@@ -3333,6 +3333,10 @@ void RasterizerStorageRD::_particles_free_data(Particles *particles) {
 	particles->particles_transforms_buffer_uniform_set = RID();
 	particles->particle_buffer = RID();
 
+	if (RD::get_singleton()->uniform_set_is_valid(particles->collision_textures_uniform_set)) {
+		RD::get_singleton()->free(particles->collision_textures_uniform_set);
+	}
+
 	if (particles->particles_sort_buffer.is_valid()) {
 		RD::get_singleton()->free(particles->particles_sort_buffer);
 		particles->particles_sort_buffer = RID();
@@ -3454,6 +3458,13 @@ void RasterizerStorageRD::particles_set_fractional_delta(RID p_particles, bool p
 	particles->fractional_delta = p_enable;
 }
 
+void RasterizerStorageRD::particles_set_collision_base_size(RID p_particles, float p_size) {
+	Particles *particles = particles_owner.getornull(p_particles);
+	ERR_FAIL_COND(!particles);
+
+	particles->collision_base_size = p_size;
+}
+
 void RasterizerStorageRD::particles_set_process_material(RID p_particles, RID p_material) {
 	Particles *particles = particles_owner.getornull(p_particles);
 	ERR_FAIL_COND(!particles);
@@ -3646,6 +3657,22 @@ RID RasterizerStorageRD::particles_get_draw_pass_mesh(RID p_particles, int p_pas
 	return particles->draw_passes[p_pass];
 }
 
+void RasterizerStorageRD::particles_add_collision(RID p_particles, RasterizerScene::InstanceBase *p_instance) {
+	Particles *particles = particles_owner.getornull(p_particles);
+	ERR_FAIL_COND(!particles);
+
+	ERR_FAIL_COND(p_instance->base_type != RS::INSTANCE_PARTICLES_COLLISION);
+
+	particles->collisions.insert(p_instance);
+}
+
+void RasterizerStorageRD::particles_remove_collision(RID p_particles, RasterizerScene::InstanceBase *p_instance) {
+	Particles *particles = particles_owner.getornull(p_particles);
+	ERR_FAIL_COND(!particles);
+
+	particles->collisions.erase(p_instance);
+}
+
 void RasterizerStorageRD::_particles_process(Particles *p_particles, float p_delta) {
 	if (p_particles->particles_material_uniform_set.is_null() || !RD::get_singleton()->uniform_set_is_valid(p_particles->particles_material_uniform_set)) {
 		Vector<RD::Uniform> uniforms;
@@ -3729,6 +3756,195 @@ void RasterizerStorageRD::_particles_process(Particles *p_particles, float p_del
 
 	frame_params.cycle = p_particles->cycle_number;
 
+	{ //collision and attractors
+
+		frame_params.collider_count = 0;
+		frame_params.attractor_count = 0;
+		frame_params.particle_size = p_particles->collision_base_size;
+
+		RID collision_3d_textures[ParticlesFrameParams::MAX_3D_TEXTURES];
+		RID collision_heightmap_texture;
+
+		Transform to_particles;
+		if (p_particles->use_local_coords) {
+			to_particles = p_particles->emission_transform.affine_inverse();
+		}
+		uint32_t collision_3d_textures_used = 0;
+		for (const Set<RasterizerScene::InstanceBase *>::Element *E = p_particles->collisions.front(); E; E = E->next()) {
+			ParticlesCollision *pc = particles_collision_owner.getornull(E->get()->base);
+			Transform to_collider = E->get()->transform;
+			if (p_particles->use_local_coords) {
+				to_collider = to_particles * to_collider;
+			}
+			Vector3 scale = to_collider.basis.get_scale();
+			to_collider.basis.orthonormalize();
+
+			if (pc->type <= RS::PARTICLES_COLLISION_TYPE_VECTOR_FIELD_ATTRACT) {
+				//attractor
+				if (frame_params.attractor_count >= ParticlesFrameParams::MAX_ATTRACTORS) {
+					continue;
+				}
+
+				ParticlesFrameParams::Attractor &attr = frame_params.attractors[frame_params.attractor_count];
+
+				store_transform(to_collider, attr.transform);
+				attr.strength = pc->attractor_strength;
+				attr.attenuation = pc->attractor_attenuation;
+				attr.directionality = pc->attractor_directionality;
+
+				switch (pc->type) {
+					case RS::PARTICLES_COLLISION_TYPE_SPHERE_ATTRACT: {
+						attr.type = ParticlesFrameParams::ATTRACTOR_TYPE_SPHERE;
+						float radius = pc->radius;
+						radius *= (scale.x + scale.y + scale.z) / 3.0;
+						attr.extents[0] = radius;
+						attr.extents[1] = radius;
+						attr.extents[2] = radius;
+					} break;
+					case RS::PARTICLES_COLLISION_TYPE_BOX_ATTRACT: {
+						attr.type = ParticlesFrameParams::ATTRACTOR_TYPE_BOX;
+						Vector3 extents = pc->extents * scale;
+						attr.extents[0] = extents.x;
+						attr.extents[1] = extents.y;
+						attr.extents[2] = extents.z;
+					} break;
+					case RS::PARTICLES_COLLISION_TYPE_VECTOR_FIELD_ATTRACT: {
+						if (collision_3d_textures_used >= ParticlesFrameParams::MAX_3D_TEXTURES) {
+							continue;
+						}
+						attr.type = ParticlesFrameParams::ATTRACTOR_TYPE_VECTOR_FIELD;
+						Vector3 extents = pc->extents * scale;
+						attr.extents[0] = extents.x;
+						attr.extents[1] = extents.y;
+						attr.extents[2] = extents.z;
+						attr.texture_index = collision_3d_textures_used;
+
+						collision_3d_textures[collision_3d_textures_used] = pc->field_texture;
+						collision_3d_textures_used++;
+					} break;
+					default: {
+					}
+				}
+
+				frame_params.attractor_count++;
+			} else {
+				//collider
+				if (frame_params.collider_count >= ParticlesFrameParams::MAX_COLLIDERS) {
+					continue;
+				}
+
+				ParticlesFrameParams::Collider &col = frame_params.colliders[frame_params.collider_count];
+
+				store_transform(to_collider, col.transform);
+				switch (pc->type) {
+					case RS::PARTICLES_COLLISION_TYPE_SPHERE_COLLIDE: {
+						col.type = ParticlesFrameParams::COLLISION_TYPE_SPHERE;
+						float radius = pc->radius;
+						radius *= (scale.x + scale.y + scale.z) / 3.0;
+						col.extents[0] = radius;
+						col.extents[1] = radius;
+						col.extents[2] = radius;
+					} break;
+					case RS::PARTICLES_COLLISION_TYPE_BOX_COLLIDE: {
+						col.type = ParticlesFrameParams::COLLISION_TYPE_BOX;
+						Vector3 extents = pc->extents * scale;
+						col.extents[0] = extents.x;
+						col.extents[1] = extents.y;
+						col.extents[2] = extents.z;
+					} break;
+					case RS::PARTICLES_COLLISION_TYPE_SDF_COLLIDE: {
+						if (collision_3d_textures_used >= ParticlesFrameParams::MAX_3D_TEXTURES) {
+							continue;
+						}
+						col.type = ParticlesFrameParams::COLLISION_TYPE_SDF;
+						Vector3 extents = pc->extents * scale;
+						col.extents[0] = extents.x;
+						col.extents[1] = extents.y;
+						col.extents[2] = extents.z;
+						col.texture_index = collision_3d_textures_used;
+						col.scale = (scale.x + scale.y + scale.z) * 0.333333333333; //non uniform scale non supported
+
+						collision_3d_textures[collision_3d_textures_used] = pc->field_texture;
+						collision_3d_textures_used++;
+					} break;
+					case RS::PARTICLES_COLLISION_TYPE_HEIGHTFIELD_COLLIDE: {
+						if (collision_heightmap_texture != RID()) { //already taken
+							continue;
+						}
+
+						col.type = ParticlesFrameParams::COLLISION_TYPE_HEIGHT_FIELD;
+						Vector3 extents = pc->extents * scale;
+						col.extents[0] = extents.x;
+						col.extents[1] = extents.y;
+						col.extents[2] = extents.z;
+						collision_heightmap_texture = pc->heightfield_texture;
+					} break;
+					default: {
+					}
+				}
+
+				frame_params.collider_count++;
+			}
+		}
+
+		bool different = false;
+		if (collision_3d_textures_used == p_particles->collision_3d_textures_used) {
+			for (int i = 0; i < ParticlesFrameParams::MAX_3D_TEXTURES; i++) {
+				if (p_particles->collision_3d_textures[i] != collision_3d_textures[i]) {
+					different = true;
+					break;
+				}
+			}
+		}
+
+		if (collision_heightmap_texture != p_particles->collision_heightmap_texture) {
+			different = true;
+		}
+
+		bool uniform_set_valid = RD::get_singleton()->uniform_set_is_valid(p_particles->collision_textures_uniform_set);
+
+		if (different || !uniform_set_valid) {
+			if (uniform_set_valid) {
+				RD::get_singleton()->free(p_particles->collision_textures_uniform_set);
+			}
+
+			Vector<RD::Uniform> uniforms;
+
+			{
+				RD::Uniform u;
+				u.type = RD::UNIFORM_TYPE_TEXTURE;
+				u.binding = 0;
+				for (uint32_t i = 0; i < ParticlesFrameParams::MAX_3D_TEXTURES; i++) {
+					RID rd_tex;
+					if (i < collision_3d_textures_used) {
+						Texture *t = texture_owner.getornull(collision_3d_textures[i]);
+						if (t && t->type == Texture::TYPE_3D) {
+							rd_tex = t->rd_texture;
+						}
+					}
+
+					if (rd_tex == RID()) {
+						rd_tex = default_rd_textures[DEFAULT_RD_TEXTURE_3D_WHITE];
+					}
+					u.ids.push_back(rd_tex);
+				}
+				uniforms.push_back(u);
+			}
+			{
+				RD::Uniform u;
+				u.type = RD::UNIFORM_TYPE_TEXTURE;
+				u.binding = 1;
+				if (collision_heightmap_texture.is_valid()) {
+					u.ids.push_back(collision_heightmap_texture);
+				} else {
+					u.ids.push_back(default_rd_textures[DEFAULT_RD_TEXTURE_BLACK]);
+				}
+				uniforms.push_back(u);
+			}
+			p_particles->collision_textures_uniform_set = RD::get_singleton()->uniform_set_create(uniforms, particles_shader.default_shader_rd, 2);
+		}
+	}
+
 	ParticlesShader::PushConstant push_constant;
 
 	push_constant.clear = p_particles->clear;
@@ -3783,8 +3999,10 @@ void RasterizerStorageRD::_particles_process(Particles *p_particles, float p_del
 	RD::get_singleton()->compute_list_bind_compute_pipeline(compute_list, m->shader_data->pipeline);
 	RD::get_singleton()->compute_list_bind_uniform_set(compute_list, particles_shader.base_uniform_set, 0);
 	RD::get_singleton()->compute_list_bind_uniform_set(compute_list, p_particles->particles_material_uniform_set, 1);
+	RD::get_singleton()->compute_list_bind_uniform_set(compute_list, p_particles->collision_textures_uniform_set, 2);
+
 	if (m->uniform_set.is_valid()) {
-		RD::get_singleton()->compute_list_bind_uniform_set(compute_list, m->uniform_set, 2);
+		RD::get_singleton()->compute_list_bind_uniform_set(compute_list, m->uniform_set, 3);
 	}
 
 	RD::get_singleton()->compute_list_set_push_constant(compute_list, &push_constant, sizeof(ParticlesShader::PushConstant));
@@ -4190,7 +4408,7 @@ void RasterizerStorageRD::ParticlesMaterialData::update_parameters(const Map<Str
 		}
 	}
 
-	uniform_set = RD::get_singleton()->uniform_set_create(uniforms, base_singleton->particles_shader.shader.version_get_shader(shader_data->version, 0), 2);
+	uniform_set = RD::get_singleton()->uniform_set_create(uniforms, base_singleton->particles_shader.shader.version_get_shader(shader_data->version, 0), 3);
 }
 
 RasterizerStorageRD::ParticlesMaterialData::~ParticlesMaterialData() {
@@ -4211,6 +4429,171 @@ RasterizerStorageRD::MaterialData *RasterizerStorageRD::_create_particles_materi
 	return material_data;
 }
 ////////
+
+/* PARTICLES COLLISION API */
+
+RID RasterizerStorageRD::particles_collision_create() {
+	return particles_collision_owner.make_rid(ParticlesCollision());
+}
+
+RID RasterizerStorageRD::particles_collision_get_heightfield_framebuffer(RID p_particles_collision) const {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND_V(!particles_collision, RID());
+	ERR_FAIL_COND_V(particles_collision->type != RS::PARTICLES_COLLISION_TYPE_HEIGHTFIELD_COLLIDE, RID());
+
+	if (particles_collision->heightfield_texture == RID()) {
+		//create
+		int resolutions[RS::PARTICLES_COLLISION_HEIGHTFIELD_RESOLUTION_MAX] = { 256, 512, 1024, 2048, 4096, 8192 };
+		Size2i size;
+		if (particles_collision->extents.x > particles_collision->extents.z) {
+			size.x = resolutions[particles_collision->heightfield_resolution];
+			size.y = int32_t(particles_collision->extents.z / particles_collision->extents.x * size.x);
+		} else {
+			size.y = resolutions[particles_collision->heightfield_resolution];
+			size.x = int32_t(particles_collision->extents.x / particles_collision->extents.z * size.y);
+		}
+
+		RD::TextureFormat tf;
+		tf.format = RD::DATA_FORMAT_D32_SFLOAT;
+		tf.width = size.x;
+		tf.height = size.y;
+		tf.type = RD::TEXTURE_TYPE_2D;
+		tf.usage_bits = RD::TEXTURE_USAGE_SAMPLING_BIT | RD::TEXTURE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
+
+		particles_collision->heightfield_texture = RD::get_singleton()->texture_create(tf, RD::TextureView());
+
+		Vector<RID> fb_tex;
+		fb_tex.push_back(particles_collision->heightfield_texture);
+		particles_collision->heightfield_fb = RD::get_singleton()->framebuffer_create(fb_tex);
+		particles_collision->heightfield_fb_size = size;
+	}
+
+	return particles_collision->heightfield_fb;
+}
+
+void RasterizerStorageRD::particles_collision_set_collision_type(RID p_particles_collision, RS::ParticlesCollisionType p_type) {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND(!particles_collision);
+
+	if (p_type == particles_collision->type) {
+		return;
+	}
+
+	if (particles_collision->heightfield_texture.is_valid()) {
+		RD::get_singleton()->free(particles_collision->heightfield_texture);
+		particles_collision->heightfield_texture = RID();
+	}
+	particles_collision->type = p_type;
+	particles_collision->instance_dependency.instance_notify_changed(true, false);
+}
+
+void RasterizerStorageRD::particles_collision_set_cull_mask(RID p_particles_collision, uint32_t p_cull_mask) {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND(!particles_collision);
+	particles_collision->cull_mask = p_cull_mask;
+}
+
+void RasterizerStorageRD::particles_collision_set_sphere_radius(RID p_particles_collision, float p_radius) {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND(!particles_collision);
+
+	particles_collision->radius = p_radius;
+	particles_collision->instance_dependency.instance_notify_changed(true, false);
+}
+
+void RasterizerStorageRD::particles_collision_set_box_extents(RID p_particles_collision, const Vector3 &p_extents) {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND(!particles_collision);
+
+	particles_collision->extents = p_extents;
+	particles_collision->instance_dependency.instance_notify_changed(true, false);
+}
+
+void RasterizerStorageRD::particles_collision_set_attractor_strength(RID p_particles_collision, float p_strength) {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND(!particles_collision);
+
+	particles_collision->attractor_strength = p_strength;
+}
+
+void RasterizerStorageRD::particles_collision_set_attractor_directionality(RID p_particles_collision, float p_directionality) {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND(!particles_collision);
+
+	particles_collision->attractor_directionality = p_directionality;
+}
+
+void RasterizerStorageRD::particles_collision_set_attractor_attenuation(RID p_particles_collision, float p_curve) {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND(!particles_collision);
+
+	particles_collision->attractor_attenuation = p_curve;
+}
+
+void RasterizerStorageRD::particles_collision_set_field_texture(RID p_particles_collision, RID p_texture) {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND(!particles_collision);
+
+	particles_collision->field_texture = p_texture;
+}
+
+void RasterizerStorageRD::particles_collision_height_field_update(RID p_particles_collision) {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND(!particles_collision);
+	particles_collision->instance_dependency.instance_notify_changed(true, false);
+}
+
+void RasterizerStorageRD::particles_collision_set_height_field_resolution(RID p_particles_collision, RS::ParticlesCollisionHeightfieldResolution p_resolution) {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND(!particles_collision);
+
+	if (particles_collision->heightfield_resolution == p_resolution) {
+		return;
+	}
+
+	particles_collision->heightfield_resolution = p_resolution;
+
+	if (particles_collision->heightfield_texture.is_valid()) {
+		RD::get_singleton()->free(particles_collision->heightfield_texture);
+		particles_collision->heightfield_texture = RID();
+	}
+}
+
+AABB RasterizerStorageRD::particles_collision_get_aabb(RID p_particles_collision) const {
+	ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND_V(!particles_collision, AABB());
+
+	switch (particles_collision->type) {
+		case RS::PARTICLES_COLLISION_TYPE_SPHERE_ATTRACT:
+		case RS::PARTICLES_COLLISION_TYPE_SPHERE_COLLIDE: {
+			AABB aabb;
+			aabb.position = -Vector3(1, 1, 1) * particles_collision->radius;
+			aabb.size = Vector3(2, 2, 2) * particles_collision->radius;
+			return aabb;
+		}
+		default: {
+			AABB aabb;
+			aabb.position = -particles_collision->extents;
+			aabb.size = particles_collision->extents * 2;
+			return aabb;
+		}
+	}
+
+	return AABB();
+}
+
+Vector3 RasterizerStorageRD::particles_collision_get_extents(RID p_particles_collision) const {
+	const ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND_V(!particles_collision, Vector3());
+	return particles_collision->extents;
+}
+
+bool RasterizerStorageRD::particles_collision_is_heightfield(RID p_particles_collision) const {
+	const ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_particles_collision);
+	ERR_FAIL_COND_V(!particles_collision, false);
+	return particles_collision->type == RS::PARTICLES_COLLISION_TYPE_HEIGHTFIELD_COLLIDE;
+}
+
 /* SKELETON API */
 
 RID RasterizerStorageRD::skeleton_create() {
@@ -4680,6 +5063,9 @@ void RasterizerStorageRD::reflection_probe_set_extents(RID p_probe, const Vector
 	ReflectionProbe *reflection_probe = reflection_probe_owner.getornull(p_probe);
 	ERR_FAIL_COND(!reflection_probe);
 
+	if (reflection_probe->extents == p_extents) {
+		return;
+	}
 	reflection_probe->extents = p_extents;
 	reflection_probe->instance_dependency.instance_notify_changed(true, false);
 }
@@ -5797,6 +6183,9 @@ void RasterizerStorageRD::base_update_dependency(RID p_base, RasterizerScene::In
 	} else if (particles_owner.owns(p_base)) {
 		Particles *p = particles_owner.getornull(p_base);
 		p_instance->update_dependency(&p->instance_dependency);
+	} else if (particles_collision_owner.owns(p_base)) {
+		ParticlesCollision *pc = particles_collision_owner.getornull(p_base);
+		p_instance->update_dependency(&pc->instance_dependency);
 	}
 }
 
@@ -5832,6 +6221,9 @@ RS::InstanceType RasterizerStorageRD::get_base_type(RID p_rid) const {
 	if (particles_owner.owns(p_rid)) {
 		return RS::INSTANCE_PARTICLES;
 	}
+	if (particles_collision_owner.owns(p_rid)) {
+		return RS::INSTANCE_PARTICLES_COLLISION;
+	}
 
 	return RS::INSTANCE_NONE;
 }
@@ -6735,8 +7127,6 @@ void RasterizerStorageRD::update_dirty_resources() {
 	_update_dirty_multimeshes();
 	_update_dirty_skeletons();
 	_update_decal_atlas();
-
-	update_particles();
 }
 
 bool RasterizerStorageRD::has_os_feature(const String &p_feature) const {
@@ -6871,6 +7261,14 @@ bool RasterizerStorageRD::free(RID p_rid) {
 		_particles_free_data(particles);
 		particles->instance_dependency.instance_notify_deleted(p_rid);
 		particles_owner.free(p_rid);
+	} else if (particles_collision_owner.owns(p_rid)) {
+		ParticlesCollision *particles_collision = particles_collision_owner.getornull(p_rid);
+
+		if (particles_collision->heightfield_texture.is_valid()) {
+			RD::get_singleton()->free(particles_collision->heightfield_texture);
+		}
+		particles_collision->instance_dependency.instance_notify_deleted(p_rid);
+		particles_collision_owner.free(p_rid);
 	} else if (render_target_owner.owns(p_rid)) {
 		RenderTarget *rt = render_target_owner.getornull(p_rid);
 
@@ -7379,14 +7777,19 @@ RasterizerStorageRD::RasterizerStorageRD() {
 		actions.renames["RESTART_COLOR"] = "restart_color";
 		actions.renames["RESTART_CUSTOM"] = "restart_custom";
 		actions.renames["emit_particle"] = "emit_particle";
+		actions.renames["COLLIDED"] = "collided";
+		actions.renames["COLLISION_NORMAL"] = "collision_normal";
+		actions.renames["COLLISION_DEPTH"] = "collision_depth";
+		actions.renames["ATTRACTOR_FORCE"] = "attractor_force";
 
 		actions.render_mode_defines["disable_force"] = "#define DISABLE_FORCE\n";
 		actions.render_mode_defines["disable_velocity"] = "#define DISABLE_VELOCITY\n";
 		actions.render_mode_defines["keep_data"] = "#define ENABLE_KEEP_DATA\n";
+		actions.render_mode_defines["collision_use_scale"] = "#define USE_COLLISON_SCALE\n";
 
 		actions.sampler_array_name = "material_samplers";
 		actions.base_texture_binding_index = 1;
-		actions.texture_layout_set = 2;
+		actions.texture_layout_set = 3;
 		actions.base_uniform_string = "material.";
 		actions.base_varying_index = 10;
 

servers/rendering/rasterizer_rd/rasterizer_storage_rd.h

@@ -475,6 +475,46 @@ private:
 	};
 
 	struct ParticlesFrameParams {
+		enum {
+			MAX_ATTRACTORS = 32,
+			MAX_COLLIDERS = 32,
+			MAX_3D_TEXTURES = 7
+		};
+
+		enum AttractorType {
+			ATTRACTOR_TYPE_SPHERE,
+			ATTRACTOR_TYPE_BOX,
+			ATTRACTOR_TYPE_VECTOR_FIELD,
+		};
+
+		struct Attractor {
+			float transform[16];
+			float extents[3]; //exents or radius
+			uint32_t type;
+
+			uint32_t texture_index; //texture index for vector field
+			float strength;
+			float attenuation;
+			float directionality;
+		};
+
+		enum CollisionType {
+			COLLISION_TYPE_SPHERE,
+			COLLISION_TYPE_BOX,
+			COLLISION_TYPE_SDF,
+			COLLISION_TYPE_HEIGHT_FIELD
+		};
+
+		struct Collider {
+			float transform[16];
+			float extents[3]; //exents or radius
+			uint32_t type;
+
+			uint32_t texture_index; //texture index for vector field
+			float scale;
+			uint32_t pad[2];
+		};
+
 		uint32_t emitting;
 		float system_phase;
 		float prev_system_phase;
@@ -486,9 +526,14 @@ private:
 		float delta;
 
 		uint32_t random_seed;
-		uint32_t pad[3];
+		uint32_t attractor_count;
+		uint32_t collider_count;
+		float particle_size;
 
 		float emission_transform[16];
+
+		Attractor attractors[MAX_ATTRACTORS];
+		Collider colliders[MAX_COLLIDERS];
 	};
 
 	struct ParticleEmissionBufferData {
@@ -536,6 +581,11 @@ private:
 		RID particles_material_uniform_set;
 		RID particles_copy_uniform_set;
 		RID particles_transforms_buffer_uniform_set;
+		RID collision_textures_uniform_set;
+
+		RID collision_3d_textures[ParticlesFrameParams::MAX_3D_TEXTURES];
+		uint32_t collision_3d_textures_used = 0;
+		RID collision_heightmap_texture;
 
 		RID particles_sort_buffer;
 		RID particles_sort_uniform_set;
@@ -557,6 +607,7 @@ private:
 		int fixed_fps;
 		bool fractional_delta;
 		float frame_remainder;
+		float collision_base_size;
 
 		bool clear;
 
@@ -569,6 +620,8 @@ private:
 		ParticleEmissionBuffer *emission_buffer = nullptr;
 		RID emission_storage_buffer;
 
+		Set<RasterizerScene::InstanceBase *> collisions;
+
 		Particles() :
 				inactive(true),
 				inactive_time(0.0),
@@ -590,6 +643,7 @@ private:
 				fixed_fps(0),
 				fractional_delta(false),
 				frame_remainder(0),
+				collision_base_size(0.01),
 				clear(true) {
 		}
 
@@ -704,6 +758,28 @@ private:
 
 	mutable RID_Owner<Particles> particles_owner;
 
+	/* Particles Collision */
+
+	struct ParticlesCollision {
+		RS::ParticlesCollisionType type = RS::PARTICLES_COLLISION_TYPE_SPHERE_ATTRACT;
+		uint32_t cull_mask = 0xFFFFFFFF;
+		float radius = 1.0;
+		Vector3 extents = Vector3(1, 1, 1);
+		float attractor_strength = 1.0;
+		float attractor_attenuation = 1.0;
+		float attractor_directionality = 0.0;
+		RID field_texture;
+		RID heightfield_texture;
+		RID heightfield_fb;
+		Size2i heightfield_fb_size;
+
+		RS::ParticlesCollisionHeightfieldResolution heightfield_resolution = RS::PARTICLES_COLLISION_HEIGHTFIELD_RESOLUTION_1024;
+
+		RasterizerScene::InstanceDependency instance_dependency;
+	};
+
+	mutable RID_Owner<ParticlesCollision> particles_collision_owner;
+
 	/* Skeleton */
 
 	struct Skeleton {
@@ -1691,6 +1767,7 @@ public:
 	void particles_set_process_material(RID p_particles, RID p_material);
 	void particles_set_fixed_fps(RID p_particles, int p_fps);
 	void particles_set_fractional_delta(RID p_particles, bool p_enable);
+	void particles_set_collision_base_size(RID p_particles, float p_size);
 	void particles_restart(RID p_particles);
 	void particles_emit(RID p_particles, const Transform &p_transform, const Vector3 &p_velocity, const Color &p_color, const Color &p_custom, uint32_t p_emit_flags);
 	void particles_set_subemitter(RID p_particles, RID p_subemitter_particles);
@@ -1748,6 +1825,27 @@ public:
 		return particles->particles_transforms_buffer_uniform_set;
 	}
 
+	virtual void particles_add_collision(RID p_particles, RasterizerScene::InstanceBase *p_instance);
+	virtual void particles_remove_collision(RID p_particles, RasterizerScene::InstanceBase *p_instance);
+
+	/* PARTICLES COLLISION */
+
+	virtual RID particles_collision_create();
+	virtual void particles_collision_set_collision_type(RID p_particles_collision, RS::ParticlesCollisionType p_type);
+	virtual void particles_collision_set_cull_mask(RID p_particles_collision, uint32_t p_cull_mask);
+	virtual void particles_collision_set_sphere_radius(RID p_particles_collision, float p_radius); //for spheres
+	virtual void particles_collision_set_box_extents(RID p_particles_collision, const Vector3 &p_extents); //for non-spheres
+	virtual void particles_collision_set_attractor_strength(RID p_particles_collision, float p_strength);
+	virtual void particles_collision_set_attractor_directionality(RID p_particles_collision, float p_directionality);
+	virtual void particles_collision_set_attractor_attenuation(RID p_particles_collision, float p_curve);
+	virtual void particles_collision_set_field_texture(RID p_particles_collision, RID p_texture); //for SDF and vector field, heightfield is dynamic
+	virtual void particles_collision_height_field_update(RID p_particles_collision); //for SDF and vector field
+	virtual void particles_collision_set_height_field_resolution(RID p_particles_collision, RS::ParticlesCollisionHeightfieldResolution p_resolution); //for SDF and vector field
+	virtual AABB particles_collision_get_aabb(RID p_particles_collision) const;
+	virtual Vector3 particles_collision_get_extents(RID p_particles_collision) const;
+	virtual bool particles_collision_is_heightfield(RID p_particles_collision) const;
+	RID particles_collision_get_heightfield_framebuffer(RID p_particles_collision) const;
+
 	/* GLOBAL VARIABLES API */
 
 	virtual void global_variable_add(const StringName &p_name, RS::GlobalVariableType p_type, const Variant &p_value);

servers/rendering/rasterizer_rd/shaders/particles.glsl

@@ -31,6 +31,40 @@ global_variables;
 /* Set 1: FRAME AND PARTICLE DATA */
 
 // a frame history is kept for trail deterministic behavior
+
+#define MAX_ATTRACTORS 32
+
+#define ATTRACTOR_TYPE_SPHERE 0
+#define ATTRACTOR_TYPE_BOX 1
+#define ATTRACTOR_TYPE_VECTOR_FIELD 2
+
+struct Attractor {
+	mat4 transform;
+	vec3 extents; //exents or radius
+	uint type;
+	uint texture_index; //texture index for vector field
+	float strength;
+	float attenuation;
+	float directionality;
+};
+
+#define MAX_COLLIDERS 32
+
+#define COLLIDER_TYPE_SPHERE 0
+#define COLLIDER_TYPE_BOX 1
+#define COLLIDER_TYPE_SDF 2
+#define COLLIDER_TYPE_HEIGHT_FIELD 3
+
+struct Collider {
+	mat4 transform;
+	vec3 extents; //exents or radius
+	uint type;
+
+	uint texture_index; //texture index for vector field
+	float scale;
+	uint pad[2];
+};
+
 struct FrameParams {
 	bool emitting;
 	float system_phase;
@@ -43,9 +77,14 @@ struct FrameParams {
 	float delta;
 
 	uint random_seed;
-	uint pad[3];
+	uint attractor_count;
+	uint collider_count;
+	float particle_size;
 
 	mat4 emission_transform;
+
+	Attractor attractors[MAX_ATTRACTORS];
+	Collider colliders[MAX_COLLIDERS];
 };
 
 layout(set = 1, binding = 0, std430) restrict buffer FrameHistory {
@@ -80,7 +119,7 @@ struct ParticleEmission {
 	vec4 custom;
 };
 
-layout(set = 1, binding = 2, std430) restrict volatile coherent buffer SourceEmission {
+layout(set = 1, binding = 2, std430) restrict buffer SourceEmission {
 	int particle_count;
 	uint pad0;
 	uint pad1;
@@ -89,7 +128,7 @@ layout(set = 1, binding = 2, std430) restrict volatile coherent buffer SourceEmi
 }
 src_particles;
 
-layout(set = 1, binding = 3, std430) restrict volatile coherent buffer DestEmission {
+layout(set = 1, binding = 3, std430) restrict buffer DestEmission {
 	int particle_count;
 	int particle_max;
 	uint pad1;
@@ -98,10 +137,17 @@ layout(set = 1, binding = 3, std430) restrict volatile coherent buffer DestEmiss
 }
 dst_particles;
 
-/* SET 2: MATERIAL */
+/* SET 2: COLLIDER/ATTRACTOR TEXTURES */
+
+#define MAX_3D_TEXTURES 7
+
+layout(set = 2, binding = 0) uniform texture3D sdf_vec_textures[MAX_3D_TEXTURES];
+layout(set = 2, binding = 1) uniform texture2D height_field_texture;
+
+/* SET 3: MATERIAL */
 
 #ifdef USE_MATERIAL_UNIFORMS
-layout(set = 2, binding = 0, std140) uniform MaterialUniforms{
+layout(set = 3, binding = 0, std140) uniform MaterialUniforms{
 	/* clang-format off */
 MATERIAL_UNIFORMS
 	/* clang-format on */
@@ -140,29 +186,7 @@ bool emit_particle(mat4 p_xform, vec3 p_velocity, vec4 p_color, vec4 p_custom, u
 		atomicAdd(dst_particles.particle_count, -1);
 		return false;
 	}
-	/*
-	valid = true;
 
-	int attempts = 256; // never trust compute
-	while(attempts-- > 0) {
-	    dst_index = dst_particles.particle_count;
-	    if (dst_index == dst_particles.particle_max) {
-		return false; //can't emit anymore
-	    }
-
-	    if (atomicCompSwap(dst_particles.particle_count, dst_index, dst_index +1 ) != dst_index) {
-		continue;
-	    }
-	    valid=true;
-	    break;
-	}
-
-	barrier();
-
-	if (!valid) {
-		return false; //gave up (attempts exhausted)
-	}
-*/
 	dst_particles.data[dst_index].xform = p_xform;
 	dst_particles.data[dst_index].velocity = p_velocity;
 	dst_particles.data[dst_index].color = p_color;
@@ -217,6 +241,199 @@ void main() {
 				vec4(0.0, 0.0, 0.0, 1.0));
 	}
 
+	bool collided = false;
+	vec3 collision_normal = vec3(0.0);
+	float collision_depth = 0.0;
+
+	vec3 attractor_force = vec3(0.0);
+
+#if !defined(DISABLE_VELOCITY)
+
+	if (PARTICLE.is_active) {
+		PARTICLE.xform[3].xyz += PARTICLE.velocity * local_delta;
+	}
+#endif
+
+	/* Process physics if active */
+
+	if (PARTICLE.is_active) {
+		for (uint i = 0; i < FRAME.attractor_count; i++) {
+			vec3 dir;
+			float amount;
+			vec3 rel_vec = PARTICLE.xform[3].xyz - FRAME.attractors[i].transform[3].xyz;
+			vec3 local_pos = rel_vec * mat3(FRAME.attractors[i].transform);
+
+			switch (FRAME.attractors[i].type) {
+				case ATTRACTOR_TYPE_SPHERE: {
+					dir = normalize(rel_vec);
+					float d = length(local_pos) / FRAME.attractors[i].extents.x;
+					if (d > 1.0) {
+						continue;
+					}
+					amount = max(0.0, 1.0 - d);
+				} break;
+				case ATTRACTOR_TYPE_BOX: {
+					dir = normalize(rel_vec);
+
+					vec3 abs_pos = abs(local_pos / FRAME.attractors[i].extents);
+					float d = max(abs_pos.x, max(abs_pos.y, abs_pos.z));
+					if (d > 1.0) {
+						continue;
+					}
+					amount = max(0.0, 1.0 - d);
+
+				} break;
+				case ATTRACTOR_TYPE_VECTOR_FIELD: {
+					vec3 uvw_pos = (local_pos / FRAME.attractors[i].extents) * 2.0 - 1.0;
+					if (any(lessThan(uvw_pos, vec3(0.0))) || any(greaterThan(uvw_pos, vec3(1.0)))) {
+						continue;
+					}
+					vec3 s = texture(sampler3D(sdf_vec_textures[FRAME.attractors[i].texture_index], material_samplers[SAMPLER_LINEAR_CLAMP]), uvw_pos).xyz;
+					dir = mat3(FRAME.attractors[i].transform) * normalize(s); //revert direction
+					amount = length(s);
+
+				} break;
+			}
+			amount = pow(amount, FRAME.attractors[i].attenuation);
+			dir = normalize(mix(dir, FRAME.attractors[i].transform[2].xyz, FRAME.attractors[i].directionality));
+			attractor_force -= amount * dir * FRAME.attractors[i].strength;
+		}
+
+		float particle_size = FRAME.particle_size;
+
+#ifdef USE_COLLISON_SCALE
+
+		particle_size *= dot(vec3(length(PARTICLE.xform[0].xyz), length(PARTICLE.xform[1].xyz), length(PARTICLE.xform[2].xyz)), vec3(0.33333333333));
+
+#endif
+
+		for (uint i = 0; i < FRAME.collider_count; i++) {
+			vec3 normal;
+			float depth;
+			bool col = false;
+
+			vec3 rel_vec = PARTICLE.xform[3].xyz - FRAME.colliders[i].transform[3].xyz;
+			vec3 local_pos = rel_vec * mat3(FRAME.colliders[i].transform);
+
+			switch (FRAME.colliders[i].type) {
+				case COLLIDER_TYPE_SPHERE: {
+					float d = length(rel_vec) - (particle_size + FRAME.colliders[i].extents.x);
+
+					if (d < 0.0) {
+						col = true;
+						depth = -d;
+						normal = normalize(rel_vec);
+					}
+
+				} break;
+				case COLLIDER_TYPE_BOX: {
+					vec3 abs_pos = abs(local_pos);
+					vec3 sgn_pos = sign(local_pos);
+
+					if (any(greaterThan(abs_pos, FRAME.colliders[i].extents))) {
+						//point outside box
+
+						vec3 closest = min(abs_pos, FRAME.colliders[i].extents);
+						vec3 rel = abs_pos - closest;
+						depth = length(rel) - particle_size;
+						if (depth < 0.0) {
+							col = true;
+							normal = mat3(FRAME.colliders[i].transform) * (normalize(rel) * sgn_pos);
+							depth = -depth;
+						}
+					} else {
+						//point inside box
+						vec3 axis_len = FRAME.colliders[i].extents - abs_pos;
+						// there has to be a faster way to do this?
+						if (all(lessThan(axis_len.xx, axis_len.yz))) {
+							normal = vec3(1, 0, 0);
+						} else if (all(lessThan(axis_len.yy, axis_len.xz))) {
+							normal = vec3(0, 1, 0);
+						} else {
+							normal = vec3(0, 0, 1);
+						}
+
+						col = true;
+						depth = dot(normal * axis_len, vec3(1)) + particle_size;
+						normal = mat3(FRAME.colliders[i].transform) * (normal * sgn_pos);
+					}
+
+				} break;
+				case COLLIDER_TYPE_SDF: {
+					vec3 apos = abs(local_pos);
+					float extra_dist = 0.0;
+					if (any(greaterThan(apos, FRAME.colliders[i].extents))) { //outside
+						vec3 mpos = min(apos, FRAME.colliders[i].extents);
+						extra_dist = distance(mpos, apos);
+					}
+
+					if (extra_dist > particle_size) {
+						continue;
+					}
+
+					vec3 uvw_pos = (local_pos / FRAME.colliders[i].extents) * 0.5 + 0.5;
+					float s = texture(sampler3D(sdf_vec_textures[FRAME.colliders[i].texture_index], material_samplers[SAMPLER_LINEAR_CLAMP]), uvw_pos).r;
+					s *= FRAME.colliders[i].scale;
+					s += extra_dist;
+					if (s < particle_size) {
+						col = true;
+						depth = particle_size - s;
+						const float EPSILON = 0.001;
+						normal = mat3(FRAME.colliders[i].transform) *
+								 normalize(
+										 vec3(
+												 texture(sampler3D(sdf_vec_textures[FRAME.colliders[i].texture_index], material_samplers[SAMPLER_LINEAR_CLAMP]), uvw_pos + vec3(EPSILON, 0.0, 0.0)).r - texture(sampler3D(sdf_vec_textures[FRAME.colliders[i].texture_index], material_samplers[SAMPLER_LINEAR_CLAMP]), uvw_pos - vec3(EPSILON, 0.0, 0.0)).r,
+												 texture(sampler3D(sdf_vec_textures[FRAME.colliders[i].texture_index], material_samplers[SAMPLER_LINEAR_CLAMP]), uvw_pos + vec3(0.0, EPSILON, 0.0)).r - texture(sampler3D(sdf_vec_textures[FRAME.colliders[i].texture_index], material_samplers[SAMPLER_LINEAR_CLAMP]), uvw_pos - vec3(0.0, EPSILON, 0.0)).r,
+												 texture(sampler3D(sdf_vec_textures[FRAME.colliders[i].texture_index], material_samplers[SAMPLER_LINEAR_CLAMP]), uvw_pos + vec3(0.0, 0.0, EPSILON)).r - texture(sampler3D(sdf_vec_textures[FRAME.colliders[i].texture_index], material_samplers[SAMPLER_LINEAR_CLAMP]), uvw_pos - vec3(0.0, 0.0, EPSILON)).r));
+					}
+
+				} break;
+				case COLLIDER_TYPE_HEIGHT_FIELD: {
+					vec3 local_pos_bottom = local_pos;
+					local_pos_bottom.y -= particle_size;
+
+					if (any(greaterThan(abs(local_pos_bottom), FRAME.colliders[i].extents))) {
+						continue;
+					}
+
+					const float DELTA = 1.0 / 8192.0;
+
+					vec3 uvw_pos = vec3(local_pos_bottom / FRAME.colliders[i].extents) * 0.5 + 0.5;
+
+					float y = 1.0 - texture(sampler2D(height_field_texture, material_samplers[SAMPLER_LINEAR_CLAMP]), uvw_pos.xz).r;
+
+					if (y > uvw_pos.y) {
+						//inside heightfield
+
+						vec3 pos1 = (vec3(uvw_pos.x, y, uvw_pos.z) * 2.0 - 1.0) * FRAME.colliders[i].extents;
+						vec3 pos2 = (vec3(uvw_pos.x + DELTA, 1.0 - texture(sampler2D(height_field_texture, material_samplers[SAMPLER_LINEAR_CLAMP]), uvw_pos.xz + vec2(DELTA, 0)).r, uvw_pos.z) * 2.0 - 1.0) * FRAME.colliders[i].extents;
+						vec3 pos3 = (vec3(uvw_pos.x, 1.0 - texture(sampler2D(height_field_texture, material_samplers[SAMPLER_LINEAR_CLAMP]), uvw_pos.xz + vec2(0, DELTA)).r, uvw_pos.z + DELTA) * 2.0 - 1.0) * FRAME.colliders[i].extents;
+
+						normal = normalize(cross(pos1 - pos2, pos1 - pos3));
+						float local_y = (vec3(local_pos / FRAME.colliders[i].extents) * 0.5 + 0.5).y;
+
+						col = true;
+						depth = dot(normal, pos1) - dot(normal, local_pos_bottom);
+					}
+
+				} break;
+			}
+
+			if (col) {
+				if (!collided) {
+					collided = true;
+					collision_normal = normal;
+					collision_depth = depth;
+				} else {
+					vec3 c = collision_normal * collision_depth;
+					c += normal * max(0.0, depth - dot(normal, c));
+					collision_normal = normalize(c);
+					collision_depth = length(c);
+				}
+			}
+		}
+	}
+
 	if (params.sub_emitter_mode) {
 		if (!PARTICLE.is_active) {
 			int src_index = atomicAdd(src_particles.particle_count, -1) - 1;
@@ -329,66 +546,4 @@ COMPUTE_SHADER_CODE
 
 		/* clang-format on */
 	}
-
-#if !defined(DISABLE_VELOCITY)
-
-	if (PARTICLE.is_active) {
-		PARTICLE.xform[3].xyz += PARTICLE.velocity * local_delta;
-	}
-#endif
-
-#if 0
-	if (PARTICLE.is_active) {
-		//execute shader
-
-
-
-
-		//!defined(DISABLE_FORCE)
-
-		if (false) {
-			vec3 force = vec3(0.0);
-			for (int i = 0; i < attractor_count; i++) {
-				vec3 rel_vec = xform[3].xyz - attractors[i].pos;
-				float dist = length(rel_vec);
-				if (attractors[i].radius < dist)
-					continue;
-				if (attractors[i].eat_radius > 0.0 && attractors[i].eat_radius > dist) {
-					out_velocity_active.a = 0.0;
-				}
-
-				rel_vec = normalize(rel_vec);
-
-				float attenuation = pow(dist / attractors[i].radius, attractors[i].attenuation);
-
-				if (attractors[i].dir == vec3(0.0)) {
-					//towards center
-					force += attractors[i].strength * rel_vec * attenuation * mass;
-				} else {
-					force += attractors[i].strength * attractors[i].dir * attenuation * mass;
-				}
-			}
-
-			out_velocity_active.xyz += force * local_delta;
-		}
-
-#if !defined(DISABLE_VELOCITY)
-
-		if (true) {
-			xform[3].xyz += out_velocity_active.xyz * local_delta;
-		}
-#endif
-	} else {
-		xform = mat4(0.0);
-	}
-
-
-	xform = transpose(xform);
-
-	out_velocity_active.a = mix(0.0, 1.0, shader_active);
-
-	out_xform_1 = xform[0];
-	out_xform_2 = xform[1];
-	out_xform_3 = xform[2];
-#endif
 }

servers/rendering/rendering_server_raster.cpp

@@ -108,6 +108,9 @@ void RenderingServerRaster::draw(bool p_swap_buffers, double frame_step) {
 
 	RSG::scene->update_dirty_instances(); //update scene stuff
 
+	RSG::scene->render_particle_colliders();
+	RSG::storage->update_particles(); //need to be done after instances are updated (colliders and particle transforms), and colliders are rendered
+
 	RSG::scene->render_probes();
 	RSG::viewport->draw_viewports();
 	RSG::canvas_render->update();

servers/rendering/rendering_server_raster.h

@@ -452,6 +452,7 @@ public:
 	BIND1(particles_restart, RID)
 	BIND6(particles_emit, RID, const Transform &, const Vector3 &, const Color &, const Color &, uint32_t)
 	BIND2(particles_set_subemitter, RID, RID)
+	BIND2(particles_set_collision_base_size, RID, float)
 
 	BIND2(particles_set_draw_order, RID, RS::ParticlesDrawOrder)
 
@@ -461,6 +462,21 @@ public:
 	BIND1R(AABB, particles_get_current_aabb, RID)
 	BIND2(particles_set_emission_transform, RID, const Transform &)
 
+	/* PARTICLES COLLISION */
+
+	BIND0R(RID, particles_collision_create)
+
+	BIND2(particles_collision_set_collision_type, RID, ParticlesCollisionType)
+	BIND2(particles_collision_set_cull_mask, RID, uint32_t)
+	BIND2(particles_collision_set_sphere_radius, RID, float)
+	BIND2(particles_collision_set_box_extents, RID, const Vector3 &)
+	BIND2(particles_collision_set_attractor_strength, RID, float)
+	BIND2(particles_collision_set_attractor_directionality, RID, float)
+	BIND2(particles_collision_set_attractor_attenuation, RID, float)
+	BIND2(particles_collision_set_field_texture, RID, RID)
+	BIND1(particles_collision_height_field_update, RID)
+	BIND2(particles_collision_set_height_field_resolution, RID, ParticlesCollisionHeightfieldResolution)
+
 #undef BINDBASE
 //from now on, calls forwarded to this singleton
 #define BINDBASE RSG::scene

servers/rendering/rendering_server_scene.cpp

@@ -193,6 +193,8 @@ void *RenderingServerScene::_instance_pair(void *p_self, OctreeElementID, Instan
 	} else if (B->base_type == RS::INSTANCE_GI_PROBE && A->base_type == RS::INSTANCE_LIGHT) {
 		InstanceGIProbeData *gi_probe = static_cast<InstanceGIProbeData *>(B->base_data);
 		return gi_probe->lights.insert(A);
+	} else if (B->base_type == RS::INSTANCE_PARTICLES_COLLISION && A->base_type == RS::INSTANCE_PARTICLES) {
+		RSG::storage->particles_add_collision(A->base, B);
 	}
 
 	return nullptr;
@@ -274,6 +276,8 @@ void RenderingServerScene::_instance_unpair(void *p_self, OctreeElementID, Insta
 		Set<Instance *>::Element *E = reinterpret_cast<Set<Instance *>::Element *>(udata);
 
 		gi_probe->lights.erase(E);
+	} else if (B->base_type == RS::INSTANCE_PARTICLES_COLLISION && A->base_type == RS::INSTANCE_PARTICLES) {
+		RSG::storage->particles_remove_collision(A->base, B);
 	}
 }
 
@@ -539,6 +543,9 @@ void RenderingServerScene::instance_set_scenario(RID p_instance, RID p_scenario)
 				RSG::scene_render->reflection_probe_release_atlas_index(reflection_probe->instance);
 
 			} break;
+			case RS::INSTANCE_PARTICLES_COLLISION: {
+				heightfield_particle_colliders_update_list.erase(instance);
+			} break;
 			case RS::INSTANCE_GI_PROBE: {
 				InstanceGIProbeData *gi_probe = static_cast<InstanceGIProbeData *>(instance->base_data);
 
@@ -701,6 +708,12 @@ void RenderingServerScene::instance_set_visible(RID p_instance, bool p_visible)
 				instance->scenario->octree.set_pairable(instance->octree_id, p_visible, 1 << RS::INSTANCE_GI_PROBE, p_visible ? (RS::INSTANCE_GEOMETRY_MASK | (1 << RS::INSTANCE_LIGHT)) : 0);
 			}
 
+		} break;
+		case RS::INSTANCE_PARTICLES_COLLISION: {
+			if (instance->octree_id && instance->scenario) {
+				instance->scenario->octree.set_pairable(instance->octree_id, p_visible, 1 << RS::INSTANCE_PARTICLES_COLLISION, p_visible ? (1 << RS::INSTANCE_PARTICLES) : 0);
+			}
+
 		} break;
 		default: {
 		}
@@ -1026,6 +1039,13 @@ void RenderingServerScene::_update_instance(Instance *p_instance) {
 		RSG::storage->particles_set_emission_transform(p_instance->base, p_instance->transform);
 	}
 
+	if (p_instance->base_type == RS::INSTANCE_PARTICLES_COLLISION) {
+		//remove materials no longer used and un-own them
+		if (RSG::storage->particles_collision_is_heightfield(p_instance->base)) {
+			heightfield_particle_colliders_update_list.insert(p_instance);
+		}
+	}
+
 	if (p_instance->aabb.has_no_surface()) {
 		return;
 	}
@@ -1085,6 +1105,11 @@ void RenderingServerScene::_update_instance(Instance *p_instance) {
 			pairable = true;
 		}
 
+		if (p_instance->base_type == RS::INSTANCE_PARTICLES_COLLISION) {
+			pairable_mask = p_instance->visible ? (1 << RS::INSTANCE_PARTICLES) : 0;
+			pairable = true;
+		}
+
 		if (p_instance->base_type == RS::INSTANCE_GI_PROBE) {
 			//lights and geometries
 			pairable_mask = p_instance->visible ? RS::INSTANCE_GEOMETRY_MASK | (1 << RS::INSTANCE_LIGHT) : 0;
@@ -1145,6 +1170,10 @@ void RenderingServerScene::_update_instance_aabb(Instance *p_instance) {
 				new_aabb = RSG::storage->particles_get_aabb(p_instance->base);
 			}
 
+		} break;
+		case RenderingServer::INSTANCE_PARTICLES_COLLISION: {
+			new_aabb = RSG::storage->particles_collision_get_aabb(p_instance->base);
+
 		} break;
 		case RenderingServer::INSTANCE_LIGHT: {
 			new_aabb = RSG::storage->light_get_aabb(p_instance->base);
@@ -2679,6 +2708,27 @@ void RenderingServerScene::render_probes() {
 	}
 }
 
+void RenderingServerScene::render_particle_colliders() {
+	while (heightfield_particle_colliders_update_list.front()) {
+		Instance *hfpc = heightfield_particle_colliders_update_list.front()->get();
+
+		if (hfpc->scenario && hfpc->base_type == RS::INSTANCE_PARTICLES_COLLISION && RSG::storage->particles_collision_is_heightfield(hfpc->base)) {
+			//update heightfield
+			int cull_count = hfpc->scenario->octree.cull_aabb(hfpc->transformed_aabb, instance_cull_result, MAX_INSTANCE_CULL); //@TODO: cull mask missing
+			for (int i = 0; i < cull_count; i++) {
+				Instance *instance = instance_cull_result[i];
+				if (!instance->visible || !((1 << instance->base_type) & (RS::INSTANCE_GEOMETRY_MASK & (~(1 << RS::INSTANCE_PARTICLES))))) { //all but particles to avoid self collision
+					cull_count--;
+					SWAP(instance_cull_result[i], instance_cull_result[cull_count]);
+				}
+			}
+
+			RSG::scene_render->render_particle_collider_heightfield(hfpc->base, hfpc->transform, (RasterizerScene::InstanceBase **)instance_cull_result, cull_count);
+		}
+		heightfield_particle_colliders_update_list.erase(heightfield_particle_colliders_update_list.front());
+	}
+}
+
 void RenderingServerScene::_update_instance_shader_parameters_from_material(Map<StringName, RasterizerScene::InstanceBase::InstanceShaderParameter> &isparams, const Map<StringName, RasterizerScene::InstanceBase::InstanceShaderParameter> &existing_isparams, RID p_material) {
 	List<RasterizerStorage::InstanceShaderParam> plist;
 	RSG::storage->material_get_instance_shader_parameters(p_material, &plist);

servers/rendering/rendering_server_scene.h

@@ -385,6 +385,8 @@ public:
 		}
 	};
 
+	Set<Instance *> heightfield_particle_colliders_update_list;
+
 	int instance_cull_count;
 	Instance *instance_cull_result[MAX_INSTANCE_CULL];
 	Instance *instance_shadow_cull_result[MAX_INSTANCE_CULL]; //used for generating shadowmaps
@@ -461,6 +463,7 @@ public:
 	void render_camera(RID p_render_buffers, Ref<XRInterface> &p_interface, XRInterface::Eyes p_eye, RID p_camera, RID p_scenario, Size2 p_viewport_size, RID p_shadow_atlas);
 	void update_dirty_instances();
 
+	void render_particle_colliders();
 	void render_probes();
 
 	TypedArray<Image> bake_render_uv2(RID p_base, const Vector<RID> &p_material_overrides, const Size2i &p_image_size);

servers/rendering/rendering_server_wrap_mt.cpp

@@ -124,6 +124,7 @@ void RenderingServerWrapMT::finish() {
 	gi_probe_free_cached_ids();
 	lightmap_free_cached_ids();
 	particles_free_cached_ids();
+	particles_collision_free_cached_ids();
 	camera_free_cached_ids();
 	viewport_free_cached_ids();
 	environment_free_cached_ids();

servers/rendering/rendering_server_wrap_mt.h

@@ -356,6 +356,8 @@ public:
 	FUNC2(particles_set_process_material, RID, RID)
 	FUNC2(particles_set_fixed_fps, RID, int)
 	FUNC2(particles_set_fractional_delta, RID, bool)
+	FUNC2(particles_set_collision_base_size, RID, float)
+
 	FUNC1R(bool, particles_is_inactive, RID)
 	FUNC1(particles_request_process, RID)
 	FUNC1(particles_restart, RID)
@@ -371,6 +373,21 @@ public:
 
 	FUNC1R(AABB, particles_get_current_aabb, RID)
 
+	/* PARTICLES COLLISION */
+
+	FUNCRID(particles_collision)
+
+	FUNC2(particles_collision_set_collision_type, RID, ParticlesCollisionType)
+	FUNC2(particles_collision_set_cull_mask, RID, uint32_t)
+	FUNC2(particles_collision_set_sphere_radius, RID, float)
+	FUNC2(particles_collision_set_box_extents, RID, const Vector3 &)
+	FUNC2(particles_collision_set_attractor_strength, RID, float)
+	FUNC2(particles_collision_set_attractor_directionality, RID, float)
+	FUNC2(particles_collision_set_attractor_attenuation, RID, float)
+	FUNC2(particles_collision_set_field_texture, RID, RID)
+	FUNC1(particles_collision_height_field_update, RID)
+	FUNC2(particles_collision_set_height_field_resolution, RID, ParticlesCollisionHeightfieldResolution)
+
 	/* CAMERA API */
 
 	FUNCRID(camera)

servers/rendering/shader_types.cpp

@@ -295,6 +295,10 @@ ShaderTypes::ShaderTypes() {
 	shader_modes[RS::SHADER_PARTICLES].functions["compute"].built_ins["RESTART_VELOCITY"] = constt(ShaderLanguage::TYPE_BOOL);
 	shader_modes[RS::SHADER_PARTICLES].functions["compute"].built_ins["RESTART_COLOR"] = constt(ShaderLanguage::TYPE_BOOL);
 	shader_modes[RS::SHADER_PARTICLES].functions["compute"].built_ins["RESTART_CUSTOM"] = constt(ShaderLanguage::TYPE_BOOL);
+	shader_modes[RS::SHADER_PARTICLES].functions["compute"].built_ins["COLLIDED"] = constt(ShaderLanguage::TYPE_BOOL);
+	shader_modes[RS::SHADER_PARTICLES].functions["compute"].built_ins["COLLISION_NORMAL"] = constt(ShaderLanguage::TYPE_VEC3);
+	shader_modes[RS::SHADER_PARTICLES].functions["compute"].built_ins["COLLISION_DEPTH"] = constt(ShaderLanguage::TYPE_FLOAT);
+	shader_modes[RS::SHADER_PARTICLES].functions["compute"].built_ins["ATTRACTOR_FORCE"] = constt(ShaderLanguage::TYPE_VEC3);
 	shader_modes[RS::SHADER_PARTICLES].functions["compute"].can_discard = false;
 
 	{
@@ -308,6 +312,7 @@ ShaderTypes::ShaderTypes() {
 		shader_modes[RS::SHADER_PARTICLES].functions["compute"].stage_functions["emit_particle"] = emit_vertex_func;
 	}
 
+	shader_modes[RS::SHADER_PARTICLES].modes.push_back("collision_use_scale");
 	shader_modes[RS::SHADER_PARTICLES].modes.push_back("disable_force");
 	shader_modes[RS::SHADER_PARTICLES].modes.push_back("disable_velocity");
 	shader_modes[RS::SHADER_PARTICLES].modes.push_back("keep_data");

servers/rendering_server.h

@@ -578,6 +578,7 @@ public:
 	virtual void particles_set_process_material(RID p_particles, RID p_material) = 0;
 	virtual void particles_set_fixed_fps(RID p_particles, int p_fps) = 0;
 	virtual void particles_set_fractional_delta(RID p_particles, bool p_enable) = 0;
+	virtual void particles_set_collision_base_size(RID p_particles, float p_size) = 0;
 	virtual bool particles_is_inactive(RID p_particles) = 0;
 	virtual void particles_request_process(RID p_particles) = 0;
 	virtual void particles_restart(RID p_particles) = 0;
@@ -609,6 +610,43 @@ public:
 
 	virtual void particles_set_emission_transform(RID p_particles, const Transform &p_transform) = 0; //this is only used for 2D, in 3D it's automatic
 
+	/* PARTICLES COLLISION API */
+
+	virtual RID particles_collision_create() = 0;
+
+	enum ParticlesCollisionType {
+		PARTICLES_COLLISION_TYPE_SPHERE_ATTRACT,
+		PARTICLES_COLLISION_TYPE_BOX_ATTRACT,
+		PARTICLES_COLLISION_TYPE_VECTOR_FIELD_ATTRACT,
+		PARTICLES_COLLISION_TYPE_SPHERE_COLLIDE,
+		PARTICLES_COLLISION_TYPE_BOX_COLLIDE,
+		PARTICLES_COLLISION_TYPE_SDF_COLLIDE,
+		PARTICLES_COLLISION_TYPE_HEIGHTFIELD_COLLIDE,
+	};
+
+	virtual void particles_collision_set_collision_type(RID p_particles_collision, ParticlesCollisionType p_type) = 0;
+	virtual void particles_collision_set_cull_mask(RID p_particles_collision, uint32_t p_cull_mask) = 0;
+	virtual void particles_collision_set_sphere_radius(RID p_particles_collision, float p_radius) = 0; //for spheres
+	virtual void particles_collision_set_box_extents(RID p_particles_collision, const Vector3 &p_extents) = 0; //for non-spheres
+	virtual void particles_collision_set_attractor_strength(RID p_particles_collision, float p_strength) = 0;
+	virtual void particles_collision_set_attractor_directionality(RID p_particles_collision, float p_directionality) = 0;
+	virtual void particles_collision_set_attractor_attenuation(RID p_particles_collision, float p_curve) = 0;
+	virtual void particles_collision_set_field_texture(RID p_particles_collision, RID p_texture) = 0; //for SDF and vector field, heightfield is dynamic
+
+	virtual void particles_collision_height_field_update(RID p_particles_collision) = 0; //for SDF and vector field
+
+	enum ParticlesCollisionHeightfieldResolution { //longest axis resolution
+		PARTICLES_COLLISION_HEIGHTFIELD_RESOLUTION_256,
+		PARTICLES_COLLISION_HEIGHTFIELD_RESOLUTION_512,
+		PARTICLES_COLLISION_HEIGHTFIELD_RESOLUTION_1024,
+		PARTICLES_COLLISION_HEIGHTFIELD_RESOLUTION_2048,
+		PARTICLES_COLLISION_HEIGHTFIELD_RESOLUTION_4096,
+		PARTICLES_COLLISION_HEIGHTFIELD_RESOLUTION_8192,
+		PARTICLES_COLLISION_HEIGHTFIELD_RESOLUTION_MAX,
+	};
+
+	virtual void particles_collision_set_height_field_resolution(RID p_particles_collision, ParticlesCollisionHeightfieldResolution p_resolution) = 0; //for SDF and vector field
+
 	/* CAMERA API */
 
 	virtual RID camera_create() = 0;
@@ -965,6 +1003,7 @@ public:
 		INSTANCE_MULTIMESH,
 		INSTANCE_IMMEDIATE,
 		INSTANCE_PARTICLES,
+		INSTANCE_PARTICLES_COLLISION,
 		INSTANCE_LIGHT,
 		INSTANCE_REFLECTION_PROBE,
 		INSTANCE_DECAL,