Implement a commandline interface that can be used in scripts - implements #42

README.md

@@ -74,3 +74,33 @@ void fragment() {
 	COLOR = hsv_offset(COLOR, 0.32, 0.2, 0.0);
 }
 ```
+
+## Commandline interface
+
+You can run Fragmented from the commandline or scripts.
+
+> Note: Headless mode is not supported. Using the commandline interface still opens a window.
+
+### Usage
+
+```
+./Fragmented cmd --shader PATH [--load-image PATH]
+
+  --shader PATH      The path to the shader
+  --output PATH      Where to write the resulting image to
+  --load-image PATH  The path to the image. This will overwrite the
+                     load directive of the shader file (optional)
+
+```
+
+You can also run `./Fragmented cmd help` to show the help message.
+
+#### Examples
+
+```
+./Fragmented cmd --shader ./examples/oklab.gdshader --output ./output.png
+```
+
+```
+./Fragmented cmd --shader ./examples/oklab.gdshader --load-image ~/Pictures/test.png --output ./output.png
+```

scenes/main.tscn

@@ -37,6 +37,7 @@ unique_name_in_owner = true
 disable_3d = true
 position = Vector2i(48, 36)
 size = Vector2i(704, 704)
+visible = false
 script = ExtResource("6_8k0ha")
 
 [node name="UserInterfaceContainer" parent="EditorWindow" instance=ExtResource("7_5ci0e")]

src/ImageCompositor.gd

@@ -44,7 +44,7 @@ func inject_step_uniform(shader_code: String) -> Shader:
 	shader.code = shader_code.insert(fragment_function_match.get_start(), "\nuniform int STEP;")
 	return shader
 
-func update() -> Array: # returns error messages (strings)
+func update(overwrite_image_path: String = "") -> Array: # returns error messages (strings)
 	# inject STEP uniform & get number of steps
 	var shader: Shader = inject_step_uniform(Filesystem.shader_code)
 	var steps: int = ShaderDirectiveParser.parse_steps_directive(shader.code)
@@ -53,11 +53,15 @@ func update() -> Array: # returns error messages (strings)
 		return ["Shader compilation failed!"]
 	var errors = []
 	# load texture(s) from //!load directive -> TEXTURE
-	var m = ShaderDirectiveParser.parse_load_directive(shader.code)
-	if len(m) < 1:
-		errors.append("Didn't find a load directive!")
-		return errors
-	var original_image_path = Filesystem.get_absolute_path(m[1])
+	var original_image_path = ""
+	if overwrite_image_path == "":
+		var m = ShaderDirectiveParser.parse_load_directive(shader.code)
+		if len(m) < 1:
+			errors.append("Didn't find a load directive!")
+			return errors
+		original_image_path = Filesystem.get_absolute_path(m[1])
+	else:
+		original_image_path = overwrite_image_path
 	var fit_image = false
 	if original_image_path != Filesystem.last_original_image_path:
 		fit_image = true

src/Main.gd

@@ -4,18 +4,66 @@ extends Node
 @onready var ui_container = %UserInterfaceContainer
 @onready var app_name = ProjectSettings.get_setting("application/config/name")
 
+func show_help():
+	print(
+		"Usage:\n\n",
+		"./Fragmented cmd --shader PATH [--load-image PATH]\n\n",
+		"  --shader PATH      The path to the shader\n",
+		"  --output PATH      Where to write the resulting image to\n",
+		"  --load-image PATH  The path to the image. This will overwrite the\n",
+		"                     load directive of the shader file (optional)\n")
+
+func parse_custom_cmdline(args: PackedStringArray):
+	var kwargs: Dictionary = {"--shader": null, "--output": null, "--load-image": null}
+	var args_len = args.size()
+	var i = 0
+	while i < args_len:
+		var a = args[i]
+		if a in kwargs && args_len > i+1:
+			i += 1
+			kwargs[a] = args[i]
+		i += 1
+	return kwargs
+
 func _ready():
-	update_title()
-	# position windows
-	get_window().position = Vector2i(
-		editor_window.position.x + editor_window.size.x + 50,
-		editor_window.position.y)
-	get_window().min_size = Vector2i(400, 400)
-	editor_window.min_size = Vector2i(560, 400)
-	# Load last opened file
-	Filesystem.remember_last_opened_file()
-	if Filesystem.last_shader_savepath != "":
-		ui_container.get_node("Editor")._on_open_shader_dialog_file_selected(Filesystem.last_shader_savepath)
+	var args = OS.get_cmdline_args()
+	if "cmd" in args: # commandline interface
+		if "help" in args:
+			show_help()
+			get_tree().quit(1)
+		else:
+			var kwargs: Dictionary = parse_custom_cmdline(args)
+			if kwargs["--shader"] == null or kwargs["--output"] == null:
+				show_help()
+				get_tree().quit(1)
+			else:
+				Filesystem.load_shader(kwargs["--shader"])
+				var errors = []
+				if kwargs["--load-image"] == null:
+					errors = await $Compositor.update()
+				else:
+					errors = await $Compositor.update(kwargs["--load-image"])
+				if errors.size() > 0:
+					print("One or more errors occurred.")
+					for e in errors:
+						printerr(e)
+					get_tree().quit(1)
+				else:
+					Filesystem.save_result(kwargs["--output"])
+					get_tree().quit(0)
+	else:
+		update_title()
+		# position windows
+		get_window().position = Vector2i(
+			editor_window.position.x + editor_window.size.x + 50,
+			editor_window.position.y)
+		get_window().min_size = Vector2i(400, 400)
+		editor_window.min_size = Vector2i(560, 400)
+		editor_window.show()
+		# Load last opened file
+		Filesystem.remember_last_opened_file()
+		if Filesystem.last_shader_savepath != "":
+			ui_container.get_node("Editor")._on_open_shader_dialog_file_selected(Filesystem.last_shader_savepath)
 
 func update_title(current_file: String = ""):
 	if current_file == "":