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godot/servers/rendering/renderer_rd/shaders/effects/tonemap.glsl
Allen Pestaluky 628df323e2 Add agx_white, agx_contrast and HDR support to the AgX tonemapper. 
Also optimize all tonemappers to perform less calculations per-pixel.

Note: unlike `white`, `agx_white` is limited to a minimum of `2.0` and defaults to `16.29`. When using a RGB10A2 render buffer, `agx_white` will be ignored and a value of `2.0` will be used instead to ensure good behavior on the Mobile renderer.
2025-12-03 09:01:39 -05:00

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#[vertex]
#version 450
#VERSION_DEFINES
layout(location = 0) out vec2 uv_interp;
void main() {
// old code, ARM driver bug on Mali-GXXx GPUs and Vulkan API 1.3.xxx
// https://github.com/godotengine/godot/pull/92817#issuecomment-2168625982
//vec2 base_arr[3] = vec2[](vec2(-1.0, -1.0), vec2(-1.0, 3.0), vec2(3.0, -1.0));
//gl_Position = vec4(base_arr[gl_VertexIndex], 0.0, 1.0);
//uv_interp = clamp(gl_Position.xy, vec2(0.0, 0.0), vec2(1.0, 1.0)) * 2.0; // saturate(x) * 2.0
vec2 vertex_base;
if (gl_VertexIndex == 0) {
vertex_base = vec2(-1.0, -1.0);
} else if (gl_VertexIndex == 1) {
vertex_base = vec2(-1.0, 3.0);
} else {
vertex_base = vec2(3.0, -1.0);
}
gl_Position = vec4(vertex_base, 0.0, 1.0);
uv_interp = clamp(vertex_base, vec2(0.0, 0.0), vec2(1.0, 1.0)) * 2.0; // saturate(x) * 2.0
}
#[fragment]
#version 450
#VERSION_DEFINES
#ifdef USE_MULTIVIEW
#extension GL_EXT_multiview : enable
#define ViewIndex gl_ViewIndex
#endif //USE_MULTIVIEW
layout(location = 0) in vec2 uv_interp;
#ifdef USE_MULTIVIEW
#define SAMPLER_FORMAT sampler2DArray
#else
#define SAMPLER_FORMAT sampler2D
#endif
layout(set = 0, binding = 0) uniform SAMPLER_FORMAT source_color;
layout(set = 1, binding = 0) uniform sampler2D source_auto_exposure;
layout(set = 2, binding = 0) uniform SAMPLER_FORMAT source_glow;
layout(set = 2, binding = 1) uniform sampler2D glow_map; // TODO needs multiview support
#ifdef USE_1D_LUT
layout(set = 3, binding = 0) uniform sampler2D source_color_correction;
#else
layout(set = 3, binding = 0) uniform sampler3D source_color_correction;
#endif
#define FLAG_USE_BCS (1 << 0)
#define FLAG_USE_GLOW (1 << 1)
#define FLAG_USE_AUTO_EXPOSURE (1 << 2)
#define FLAG_USE_COLOR_CORRECTION (1 << 3)
#define FLAG_USE_FXAA (1 << 4)
#define FLAG_USE_8_BIT_DEBANDING (1 << 5)
#define FLAG_CONVERT_TO_SRGB (1 << 6)
layout(push_constant, std430) uniform Params {
vec3 bcs;
uint flags;
vec2 pixel_size;
uint tonemapper;
uint pad;
uvec2 glow_texture_size;
float glow_intensity;
float glow_map_strength;
uint glow_mode;
float glow_levels[7];
float exposure;
float white;
float auto_exposure_scale;
float luminance_multiplier;
vec4 tonemapper_params;
}
params;
layout(location = 0) out vec4 frag_color;
// Based on Reinhard's extended formula, see equation 4 in https://doi.org/cjbgrt
vec3 tonemap_reinhard(vec3 color) {
float white_squared = params.tonemapper_params.x;
vec3 white_squared_color = white_squared * color;
// Equivalent to color * (1 + color / white_squared) / (1 + color)
return (white_squared_color + color * color) / (white_squared_color + white_squared);
}
vec3 tonemap_filmic(vec3 color) {
// These constants must match the those in the C++ code that calculates the parameters.
// exposure_bias: Input scale (color *= bias, env->white *= bias) to make the brightness consistent with other tonemappers.
// Also useful to scale the input to the range that the tonemapper is designed for (some require very high input values).
// Has no effect on the curve's general shape or visual properties.
const float exposure_bias = 2.0f;
const float A = 0.22f * exposure_bias * exposure_bias; // bias baked into constants for performance
const float B = 0.30f * exposure_bias;
const float C = 0.10f;
const float D = 0.20f;
const float E = 0.01f;
const float F = 0.30f;
vec3 color_tonemapped = ((color * (A * color + C * B) + D * E) / (color * (A * color + B) + D * F)) - E / F;
return color_tonemapped / params.tonemapper_params.x;
}
// Adapted from https://github.com/TheRealMJP/BakingLab/blob/master/BakingLab/ACES.hlsl
// (MIT License).
vec3 tonemap_aces(vec3 color) {
// These constants must match the those in the C++ code that calculates the parameters.
const float exposure_bias = 1.8f;
const float A = 0.0245786f;
const float B = 0.000090537f;
const float C = 0.983729f;
const float D = 0.432951f;
const float E = 0.238081f;
// Exposure bias baked into transform to save shader instructions. Equivalent to `color *= exposure_bias`
const mat3 rgb_to_rrt = mat3(
vec3(0.59719f * exposure_bias, 0.35458f * exposure_bias, 0.04823f * exposure_bias),
vec3(0.07600f * exposure_bias, 0.90834f * exposure_bias, 0.01566f * exposure_bias),
vec3(0.02840f * exposure_bias, 0.13383f * exposure_bias, 0.83777f * exposure_bias));
const mat3 odt_to_rgb = mat3(
vec3(1.60475f, -0.53108f, -0.07367f),
vec3(-0.10208f, 1.10813f, -0.00605f),
vec3(-0.00327f, -0.07276f, 1.07602f));
color *= rgb_to_rrt;
vec3 color_tonemapped = (color * (color + A) - B) / (color * (C * color + D) + E);
color_tonemapped *= odt_to_rgb;
return color_tonemapped / params.tonemapper_params.x;
}
// allenwp tonemapping curve; developed for use in the Godot game engine.
// Source and details: https://allenwp.com/blog/2025/05/29/allenwp-tonemapping-curve/
// Input must be a non-negative linear scene value.
vec3 allenwp_curve(vec3 x) {
const float output_max_value = 1.0; // SDR always has an output_max_value of 1.0
// These constants must match the those in the C++ code that calculates the parameters.
// 18% "middle gray" is perceptually 50% of the brightness of reference white.
const float awp_crossover_point = 0.18;
// When output_max_value and/or awp_crossover_point are no longer constant,
// awp_shoulder_max can be calculated on the CPU and passed in as params.tonemap_e.
const float awp_shoulder_max = output_max_value - awp_crossover_point;
float awp_contrast = params.tonemapper_params.x;
float awp_toe_a = params.tonemapper_params.y;
float awp_slope = params.tonemapper_params.z;
float awp_w = params.tonemapper_params.w;
// Reinhard-like shoulder:
vec3 s = x - awp_crossover_point;
vec3 slope_s = awp_slope * s;
s = slope_s * (1.0 + s / awp_w) / (1.0 + (slope_s / awp_shoulder_max));
s += awp_crossover_point;
// Sigmoid power function toe:
vec3 t = pow(x, vec3(awp_contrast));
t = t / (t + awp_toe_a);
return mix(s, t, lessThan(x, vec3(awp_crossover_point)));
}
// This is an approximation and simplification of EaryChow's AgX implementation that is used by Blender.
// This code is based off of the script that generates the AgX_Base_sRGB.cube LUT that Blender uses.
// Source: https://github.com/EaryChow/AgX_LUT_Gen/blob/main/AgXBasesRGB.py
// Colorspace transformation source: https://www.colour-science.org:8010/apps/rgb_colourspace_transformation_matrix
vec3 tonemap_agx(vec3 color) {
// Input color should be non-negative!
// Large negative values in one channel and large positive values in other
// channels can result in a colour that appears darker and more saturated than
// desired after passing it through the inset matrix. For this reason, it is
// best to prevent negative input values.
// This is done before the Rec. 2020 transform to allow the Rec. 2020
// transform to be combined with the AgX inset matrix. This results in a loss
// of color information that could be correctly interpreted within the
// Rec. 2020 color space as positive RGB values, but is often not worth
// the performance cost of an additional matrix multiplication.
//
// Additionally, this AgX configuration was created subjectively based on
// output appearance in the Rec. 709 color gamut, so it is possible that these
// matrices will not perform well with non-Rec. 709 output (more testing with
// future wide-gamut displays is be needed).
// See this comment from the author on the decisions made to create the matrices:
// https://github.com/godotengine/godot-proposals/issues/12317#issuecomment-2835824250
// Combined Rec. 709 to Rec. 2020 and Blender AgX inset matrices:
const mat3 rec709_to_rec2020_agx_inset_matrix = mat3(
0.544814746488245, 0.140416948464053, 0.0888104196149096,
0.373787398372697, 0.754137554567394, 0.178871756420858,
0.0813978551390581, 0.105445496968552, 0.732317823964232);
// Combined inverse AgX outset matrix and Rec. 2020 to Rec. 709 matrices.
const mat3 agx_outset_rec2020_to_rec709_matrix = mat3(
1.96488741169489, -0.299313364904742, -0.164352742528393,
-0.855988495690215, 1.32639796461980, -0.238183969428088,
-0.108898916004672, -0.0270845997150571, 1.40253671195648);
const float output_max_value = 1.0; // SDR always has an output_max_value of 1.0
// Apply inset matrix.
color = rec709_to_rec2020_agx_inset_matrix * color;
// Use the allenwp tonemapping curve to match the Blender AgX curve while
// providing stability across all variable dyanimc range (SDR, HDR, EDR).
color = allenwp_curve(color);
// Clipping to output_max_value is required to address a cyan colour that occurs
// with very bright inputs.
color = min(vec3(output_max_value), color);
// Apply outset to make the result more chroma-laden and then go back to Rec. 709.
color = agx_outset_rec2020_to_rec709_matrix * color;
// Blender's lusRGB.compensate_low_side is too complex for this shader, so
// simply return the color, even if it has negative components. These negative
// components may be useful for subsequent color adjustments.
return color;
}
vec3 linear_to_srgb(vec3 color) {
const vec3 a = vec3(0.055f);
return mix((vec3(1.0f) + a) * pow(color.rgb, vec3(1.0f / 2.4f)) - a, 12.92f * color.rgb, lessThan(color.rgb, vec3(0.0031308f)));
}
vec3 srgb_to_linear(vec3 color) {
const vec3 a = vec3(0.055f);
return mix(pow((color.rgb + a) * (1.0f / (vec3(1.0f) + a)), vec3(2.4f)), color.rgb * (1.0f / 12.92f), lessThan(color.rgb, vec3(0.04045f)));
}
#define TONEMAPPER_LINEAR 0
#define TONEMAPPER_REINHARD 1
#define TONEMAPPER_FILMIC 2
#define TONEMAPPER_ACES 3
#define TONEMAPPER_AGX 4
vec3 apply_tonemapping(vec3 color) { // inputs are LINEAR
if (params.tonemapper == TONEMAPPER_LINEAR) {
return color;
}
// Ensure color values passed to tonemappers are positive.
// They can be negative in the case of negative lights, which leads to undesired behavior.
color = max(vec3(0.0), color);
if (params.tonemapper == TONEMAPPER_REINHARD) {
return tonemap_reinhard(color);
} else if (params.tonemapper == TONEMAPPER_FILMIC) {
return tonemap_filmic(color);
} else if (params.tonemapper == TONEMAPPER_ACES) {
return tonemap_aces(color);
} else { // TONEMAPPER_AGX
return tonemap_agx(color);
}
}
#ifdef USE_GLOW_FILTER_BICUBIC
// w0, w1, w2, and w3 are the four cubic B-spline basis functions
float w0(float a) {
return (1.0f / 6.0f) * (a * (a * (-a + 3.0f) - 3.0f) + 1.0f);
}
float w1(float a) {
return (1.0f / 6.0f) * (a * a * (3.0f * a - 6.0f) + 4.0f);
}
float w2(float a) {
return (1.0f / 6.0f) * (a * (a * (-3.0f * a + 3.0f) + 3.0f) + 1.0f);
}
float w3(float a) {
return (1.0f / 6.0f) * (a * a * a);
}
// g0 and g1 are the two amplitude functions
float g0(float a) {
return w0(a) + w1(a);
}
float g1(float a) {
return w2(a) + w3(a);
}
// h0 and h1 are the two offset functions
float h0(float a) {
return -1.0f + w1(a) / (w0(a) + w1(a));
}
float h1(float a) {
return 1.0f + w3(a) / (w2(a) + w3(a));
}
#ifdef USE_MULTIVIEW
vec4 texture2D_bicubic(sampler2DArray tex, vec2 uv, int p_lod) {
float lod = float(p_lod);
vec2 tex_size = vec2(params.glow_texture_size >> p_lod);
vec2 pixel_size = vec2(1.0f) / tex_size;
uv = uv * tex_size + vec2(0.5f);
vec2 iuv = floor(uv);
vec2 fuv = fract(uv);
float g0x = g0(fuv.x);
float g1x = g1(fuv.x);
float h0x = h0(fuv.x);
float h1x = h1(fuv.x);
float h0y = h0(fuv.y);
float h1y = h1(fuv.y);
vec3 p0 = vec3((vec2(iuv.x + h0x, iuv.y + h0y) - vec2(0.5f)) * pixel_size, ViewIndex);
vec3 p1 = vec3((vec2(iuv.x + h1x, iuv.y + h0y) - vec2(0.5f)) * pixel_size, ViewIndex);
vec3 p2 = vec3((vec2(iuv.x + h0x, iuv.y + h1y) - vec2(0.5f)) * pixel_size, ViewIndex);
vec3 p3 = vec3((vec2(iuv.x + h1x, iuv.y + h1y) - vec2(0.5f)) * pixel_size, ViewIndex);
return (g0(fuv.y) * (g0x * textureLod(tex, p0, lod) + g1x * textureLod(tex, p1, lod))) +
(g1(fuv.y) * (g0x * textureLod(tex, p2, lod) + g1x * textureLod(tex, p3, lod)));
}
#define GLOW_TEXTURE_SAMPLE(m_tex, m_uv, m_lod) texture2D_bicubic(m_tex, m_uv, m_lod)
#else // USE_MULTIVIEW
vec4 texture2D_bicubic(sampler2D tex, vec2 uv, int p_lod) {
float lod = float(p_lod);
vec2 tex_size = vec2(params.glow_texture_size >> p_lod);
vec2 pixel_size = vec2(1.0f) / tex_size;
uv = uv * tex_size + vec2(0.5f);
vec2 iuv = floor(uv);
vec2 fuv = fract(uv);
float g0x = g0(fuv.x);
float g1x = g1(fuv.x);
float h0x = h0(fuv.x);
float h1x = h1(fuv.x);
float h0y = h0(fuv.y);
float h1y = h1(fuv.y);
vec2 p0 = (vec2(iuv.x + h0x, iuv.y + h0y) - vec2(0.5f)) * pixel_size;
vec2 p1 = (vec2(iuv.x + h1x, iuv.y + h0y) - vec2(0.5f)) * pixel_size;
vec2 p2 = (vec2(iuv.x + h0x, iuv.y + h1y) - vec2(0.5f)) * pixel_size;
vec2 p3 = (vec2(iuv.x + h1x, iuv.y + h1y) - vec2(0.5f)) * pixel_size;
return (g0(fuv.y) * (g0x * textureLod(tex, p0, lod) + g1x * textureLod(tex, p1, lod))) +
(g1(fuv.y) * (g0x * textureLod(tex, p2, lod) + g1x * textureLod(tex, p3, lod)));
}
#define GLOW_TEXTURE_SAMPLE(m_tex, m_uv, m_lod) texture2D_bicubic(m_tex, m_uv, m_lod)
#endif // !USE_MULTIVIEW
#else // USE_GLOW_FILTER_BICUBIC
#ifdef USE_MULTIVIEW
#define GLOW_TEXTURE_SAMPLE(m_tex, m_uv, m_lod) textureLod(m_tex, vec3(m_uv, ViewIndex), float(m_lod))
#else // USE_MULTIVIEW
#define GLOW_TEXTURE_SAMPLE(m_tex, m_uv, m_lod) textureLod(m_tex, m_uv, float(m_lod))
#endif // !USE_MULTIVIEW
#endif // !USE_GLOW_FILTER_BICUBIC
vec3 gather_glow(SAMPLER_FORMAT tex, vec2 uv) { // sample all selected glow levels
vec3 glow = vec3(0.0f);
if (params.glow_levels[0] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 0).rgb * params.glow_levels[0];
}
if (params.glow_levels[1] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 1).rgb * params.glow_levels[1];
}
if (params.glow_levels[2] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 2).rgb * params.glow_levels[2];
}
if (params.glow_levels[3] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 3).rgb * params.glow_levels[3];
}
if (params.glow_levels[4] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 4).rgb * params.glow_levels[4];
}
if (params.glow_levels[5] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 5).rgb * params.glow_levels[5];
}
if (params.glow_levels[6] > 0.0001) {
glow += GLOW_TEXTURE_SAMPLE(tex, uv, 6).rgb * params.glow_levels[6];
}
glow = glow * params.luminance_multiplier;
return glow;
}
#define GLOW_MODE_ADD 0
#define GLOW_MODE_SCREEN 1
#define GLOW_MODE_SOFTLIGHT 2
#define GLOW_MODE_REPLACE 3
#define GLOW_MODE_MIX 4
// Applies glow using the selected blending mode. Does not handle the mix blend mode.
vec3 apply_glow(vec3 color, vec3 glow, float white) {
if (params.glow_mode == GLOW_MODE_ADD) {
return color + glow;
} else if (params.glow_mode == GLOW_MODE_SCREEN) {
// Glow cannot be above 1.0 after normalizing and should be non-negative
// to produce expected results. It is possible that glow can be negative
// if negative lights were used in the scene.
// We clamp to white because glow will be normalized to this range.
// Note: white cannot be smaller than the maximum output value.
glow.rgb = clamp(glow.rgb, 0.0, white);
// Normalize to white range.
//glow.rgb /= white;
//color.rgb /= white;
//color.rgb = (color.rgb + glow.rgb) - (color.rgb * glow.rgb);
// Expand back to original range.
//color.rgb *= white;
// The following is a mathematically simplified version of the above.
color.rgb = color.rgb + glow.rgb - (color.rgb * glow.rgb / white);
return color;
} else if (params.glow_mode == GLOW_MODE_SOFTLIGHT) {
// Glow cannot be above 1.0 should be non-negative to produce
// expected results. It is possible that glow can be negative
// if negative lights were used in the scene.
// Note: This approach causes a discontinuity with scene values
// at 1.0, but because this glow should have its strongest influence
// anchored at 0.25 there is no way around this.
glow.rgb = clamp(glow.rgb, 0.0, 1.0);
color.r = color.r > 1.0 ? color.r : color.r + glow.r * ((color.r <= 0.25f ? ((16.0f * color.r - 12.0f) * color.r + 4.0f) * color.r : sqrt(color.r)) - color.r);
color.g = color.g > 1.0 ? color.g : color.g + glow.g * ((color.g <= 0.25f ? ((16.0f * color.g - 12.0f) * color.g + 4.0f) * color.g : sqrt(color.g)) - color.g);
color.b = color.b > 1.0 ? color.b : color.b + glow.b * ((color.b <= 0.25f ? ((16.0f * color.b - 12.0f) * color.b + 4.0f) * color.b : sqrt(color.b)) - color.b);
return color;
} else { //replace
return glow;
}
}
#ifdef USE_1D_LUT
vec3 apply_color_correction(vec3 color) {
color.r = texture(source_color_correction, vec2(color.r, 0.0f)).r;
color.g = texture(source_color_correction, vec2(color.g, 0.0f)).g;
color.b = texture(source_color_correction, vec2(color.b, 0.0f)).b;
return color;
}
#else
vec3 apply_color_correction(vec3 color) {
return textureLod(source_color_correction, color, 0.0).rgb;
}
#endif
// FXAA 3.11 compact, Ported from https://github.com/kosua20/Rendu/blob/master/resources/common/shaders/screens/fxaa.frag
///////////////////////////////////////////////////////////////////////////////////
// MIT License
//
// Copyright (c) 2017 Simon Rodriguez
//
// 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.
///////////////////////////////////////////////////////////////////////////////////
// Nvidia Original FXAA 3.11 License
//----------------------------------------------------------------------------------
// File: es3-kepler\FXAA/FXAA3_11.h
// SDK Version: v3.00
// Email: gameworks@nvidia.com
// Site: http://developer.nvidia.com/
//
// Copyright (c) 2014-2015, NVIDIA CORPORATION. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of NVIDIA CORPORATION nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//----------------------------------------------------------------------------------
//
// NVIDIA FXAA 3.11 by TIMOTHY LOTTES
//
//----------------------------------------------------------------------------------
float QUALITY(float q) {
return (q < 5 ? 1.0 : (q > 5 ? (q < 10 ? 2.0 : (q < 11 ? 4.0 : 8.0)) : 1.5));
}
float rgb2luma(vec3 rgb) {
return sqrt(dot(rgb, vec3(0.299, 0.587, 0.114)));
}
vec3 do_fxaa(vec3 color, float exposure, vec2 uv_interp) {
const float EDGE_THRESHOLD_MIN = 0.0312;
const float EDGE_THRESHOLD_MAX = 0.125;
const int ITERATIONS = 12;
const float SUBPIXEL_QUALITY = 0.75;
#ifdef USE_MULTIVIEW
float lumaUp = rgb2luma(textureLodOffset(source_color, vec3(uv_interp, ViewIndex), 0.0, ivec2(0, 1)).xyz * exposure * params.luminance_multiplier);
float lumaDown = rgb2luma(textureLodOffset(source_color, vec3(uv_interp, ViewIndex), 0.0, ivec2(0, -1)).xyz * exposure * params.luminance_multiplier);
float lumaLeft = rgb2luma(textureLodOffset(source_color, vec3(uv_interp, ViewIndex), 0.0, ivec2(-1, 0)).xyz * exposure * params.luminance_multiplier);
float lumaRight = rgb2luma(textureLodOffset(source_color, vec3(uv_interp, ViewIndex), 0.0, ivec2(1, 0)).xyz * exposure * params.luminance_multiplier);
float lumaCenter = rgb2luma(color);
float lumaMin = min(lumaCenter, min(min(lumaUp, lumaDown), min(lumaLeft, lumaRight)));
float lumaMax = max(lumaCenter, max(max(lumaUp, lumaDown), max(lumaLeft, lumaRight)));
float lumaRange = lumaMax - lumaMin;
if (lumaRange < max(EDGE_THRESHOLD_MIN, lumaMax * EDGE_THRESHOLD_MAX)) {
return color;
}
float lumaDownLeft = rgb2luma(textureLodOffset(source_color, vec3(uv_interp, ViewIndex), 0.0, ivec2(-1, -1)).xyz * exposure * params.luminance_multiplier);
float lumaUpRight = rgb2luma(textureLodOffset(source_color, vec3(uv_interp, ViewIndex), 0.0, ivec2(1, 1)).xyz * exposure * params.luminance_multiplier);
float lumaUpLeft = rgb2luma(textureLodOffset(source_color, vec3(uv_interp, ViewIndex), 0.0, ivec2(-1, 1)).xyz * exposure * params.luminance_multiplier);
float lumaDownRight = rgb2luma(textureLodOffset(source_color, vec3(uv_interp, ViewIndex), 0.0, ivec2(1, -1)).xyz * exposure * params.luminance_multiplier);
float lumaDownUp = lumaDown + lumaUp;
float lumaLeftRight = lumaLeft + lumaRight;
float lumaLeftCorners = lumaDownLeft + lumaUpLeft;
float lumaDownCorners = lumaDownLeft + lumaDownRight;
float lumaRightCorners = lumaDownRight + lumaUpRight;
float lumaUpCorners = lumaUpRight + lumaUpLeft;
float edgeHorizontal = abs(-2.0 * lumaLeft + lumaLeftCorners) + abs(-2.0 * lumaCenter + lumaDownUp) * 2.0 + abs(-2.0 * lumaRight + lumaRightCorners);
float edgeVertical = abs(-2.0 * lumaUp + lumaUpCorners) + abs(-2.0 * lumaCenter + lumaLeftRight) * 2.0 + abs(-2.0 * lumaDown + lumaDownCorners);
bool isHorizontal = (edgeHorizontal >= edgeVertical);
float stepLength = isHorizontal ? params.pixel_size.y : params.pixel_size.x;
float luma1 = isHorizontal ? lumaDown : lumaLeft;
float luma2 = isHorizontal ? lumaUp : lumaRight;
float gradient1 = luma1 - lumaCenter;
float gradient2 = luma2 - lumaCenter;
bool is1Steepest = abs(gradient1) >= abs(gradient2);
float gradientScaled = 0.25 * max(abs(gradient1), abs(gradient2));
float lumaLocalAverage = 0.0;
if (is1Steepest) {
stepLength = -stepLength;
lumaLocalAverage = 0.5 * (luma1 + lumaCenter);
} else {
lumaLocalAverage = 0.5 * (luma2 + lumaCenter);
}
vec2 currentUv = uv_interp;
if (isHorizontal) {
currentUv.y += stepLength * 0.5;
} else {
currentUv.x += stepLength * 0.5;
}
vec2 offset = isHorizontal ? vec2(params.pixel_size.x, 0.0) : vec2(0.0, params.pixel_size.y);
vec3 uv1 = vec3(currentUv - offset * QUALITY(0), ViewIndex);
vec3 uv2 = vec3(currentUv + offset * QUALITY(0), ViewIndex);
float lumaEnd1 = rgb2luma(textureLod(source_color, uv1, 0.0).xyz * exposure * params.luminance_multiplier);
float lumaEnd2 = rgb2luma(textureLod(source_color, uv2, 0.0).xyz * exposure * params.luminance_multiplier);
lumaEnd1 -= lumaLocalAverage;
lumaEnd2 -= lumaLocalAverage;
bool reached1 = abs(lumaEnd1) >= gradientScaled;
bool reached2 = abs(lumaEnd2) >= gradientScaled;
bool reachedBoth = reached1 && reached2;
if (!reached1) {
uv1 -= vec3(offset * QUALITY(1), 0.0);
}
if (!reached2) {
uv2 += vec3(offset * QUALITY(1), 0.0);
}
if (!reachedBoth) {
for (int i = 2; i < ITERATIONS; i++) {
if (!reached1) {
lumaEnd1 = rgb2luma(textureLod(source_color, uv1, 0.0).xyz * exposure * params.luminance_multiplier);
lumaEnd1 = lumaEnd1 - lumaLocalAverage;
}
if (!reached2) {
lumaEnd2 = rgb2luma(textureLod(source_color, uv2, 0.0).xyz * exposure * params.luminance_multiplier);
lumaEnd2 = lumaEnd2 - lumaLocalAverage;
}
reached1 = abs(lumaEnd1) >= gradientScaled;
reached2 = abs(lumaEnd2) >= gradientScaled;
reachedBoth = reached1 && reached2;
if (!reached1) {
uv1 -= vec3(offset * QUALITY(i), 0.0);
}
if (!reached2) {
uv2 += vec3(offset * QUALITY(i), 0.0);
}
if (reachedBoth) {
break;
}
}
}
float distance1 = isHorizontal ? (uv_interp.x - uv1.x) : (uv_interp.y - uv1.y);
float distance2 = isHorizontal ? (uv2.x - uv_interp.x) : (uv2.y - uv_interp.y);
bool isDirection1 = distance1 < distance2;
float distanceFinal = min(distance1, distance2);
float edgeThickness = (distance1 + distance2);
bool isLumaCenterSmaller = lumaCenter < lumaLocalAverage;
bool correctVariation1 = (lumaEnd1 < 0.0) != isLumaCenterSmaller;
bool correctVariation2 = (lumaEnd2 < 0.0) != isLumaCenterSmaller;
bool correctVariation = isDirection1 ? correctVariation1 : correctVariation2;
float pixelOffset = -distanceFinal / edgeThickness + 0.5;
float finalOffset = correctVariation ? pixelOffset : 0.0;
float lumaAverage = (1.0 / 12.0) * (2.0 * (lumaDownUp + lumaLeftRight) + lumaLeftCorners + lumaRightCorners);
float subPixelOffset1 = clamp(abs(lumaAverage - lumaCenter) / lumaRange, 0.0, 1.0);
float subPixelOffset2 = (-2.0 * subPixelOffset1 + 3.0) * subPixelOffset1 * subPixelOffset1;
float subPixelOffsetFinal = subPixelOffset2 * subPixelOffset2 * SUBPIXEL_QUALITY;
finalOffset = max(finalOffset, subPixelOffsetFinal);
vec3 finalUv = vec3(uv_interp, ViewIndex);
if (isHorizontal) {
finalUv.y += finalOffset * stepLength;
} else {
finalUv.x += finalOffset * stepLength;
}
vec3 finalColor = textureLod(source_color, finalUv, 0.0).xyz * exposure * params.luminance_multiplier;
return finalColor;
#else
float lumaUp = rgb2luma(textureLodOffset(source_color, uv_interp, 0.0, ivec2(0, 1)).xyz * exposure * params.luminance_multiplier);
float lumaDown = rgb2luma(textureLodOffset(source_color, uv_interp, 0.0, ivec2(0, -1)).xyz * exposure * params.luminance_multiplier);
float lumaLeft = rgb2luma(textureLodOffset(source_color, uv_interp, 0.0, ivec2(-1, 0)).xyz * exposure * params.luminance_multiplier);
float lumaRight = rgb2luma(textureLodOffset(source_color, uv_interp, 0.0, ivec2(1, 0)).xyz * exposure * params.luminance_multiplier);
float lumaCenter = rgb2luma(color);
float lumaMin = min(lumaCenter, min(min(lumaUp, lumaDown), min(lumaLeft, lumaRight)));
float lumaMax = max(lumaCenter, max(max(lumaUp, lumaDown), max(lumaLeft, lumaRight)));
float lumaRange = lumaMax - lumaMin;
if (lumaRange < max(EDGE_THRESHOLD_MIN, lumaMax * EDGE_THRESHOLD_MAX)) {
return color;
}
float lumaDownLeft = rgb2luma(textureLodOffset(source_color, uv_interp, 0.0, ivec2(-1, -1)).xyz * exposure * params.luminance_multiplier);
float lumaUpRight = rgb2luma(textureLodOffset(source_color, uv_interp, 0.0, ivec2(1, 1)).xyz * exposure * params.luminance_multiplier);
float lumaUpLeft = rgb2luma(textureLodOffset(source_color, uv_interp, 0.0, ivec2(-1, 1)).xyz * exposure * params.luminance_multiplier);
float lumaDownRight = rgb2luma(textureLodOffset(source_color, uv_interp, 0.0, ivec2(1, -1)).xyz * exposure * params.luminance_multiplier);
float lumaDownUp = lumaDown + lumaUp;
float lumaLeftRight = lumaLeft + lumaRight;
float lumaLeftCorners = lumaDownLeft + lumaUpLeft;
float lumaDownCorners = lumaDownLeft + lumaDownRight;
float lumaRightCorners = lumaDownRight + lumaUpRight;
float lumaUpCorners = lumaUpRight + lumaUpLeft;
float edgeHorizontal = abs(-2.0 * lumaLeft + lumaLeftCorners) + abs(-2.0 * lumaCenter + lumaDownUp) * 2.0 + abs(-2.0 * lumaRight + lumaRightCorners);
float edgeVertical = abs(-2.0 * lumaUp + lumaUpCorners) + abs(-2.0 * lumaCenter + lumaLeftRight) * 2.0 + abs(-2.0 * lumaDown + lumaDownCorners);
bool isHorizontal = (edgeHorizontal >= edgeVertical);
float stepLength = isHorizontal ? params.pixel_size.y : params.pixel_size.x;
float luma1 = isHorizontal ? lumaDown : lumaLeft;
float luma2 = isHorizontal ? lumaUp : lumaRight;
float gradient1 = luma1 - lumaCenter;
float gradient2 = luma2 - lumaCenter;
bool is1Steepest = abs(gradient1) >= abs(gradient2);
float gradientScaled = 0.25 * max(abs(gradient1), abs(gradient2));
float lumaLocalAverage = 0.0;
if (is1Steepest) {
stepLength = -stepLength;
lumaLocalAverage = 0.5 * (luma1 + lumaCenter);
} else {
lumaLocalAverage = 0.5 * (luma2 + lumaCenter);
}
vec2 currentUv = uv_interp;
if (isHorizontal) {
currentUv.y += stepLength * 0.5;
} else {
currentUv.x += stepLength * 0.5;
}
vec2 offset = isHorizontal ? vec2(params.pixel_size.x, 0.0) : vec2(0.0, params.pixel_size.y);
vec2 uv1 = currentUv - offset * QUALITY(0);
vec2 uv2 = currentUv + offset * QUALITY(0);
float lumaEnd1 = rgb2luma(textureLod(source_color, uv1, 0.0).xyz * exposure * params.luminance_multiplier);
float lumaEnd2 = rgb2luma(textureLod(source_color, uv2, 0.0).xyz * exposure * params.luminance_multiplier);
lumaEnd1 -= lumaLocalAverage;
lumaEnd2 -= lumaLocalAverage;
bool reached1 = abs(lumaEnd1) >= gradientScaled;
bool reached2 = abs(lumaEnd2) >= gradientScaled;
bool reachedBoth = reached1 && reached2;
if (!reached1) {
uv1 -= offset * QUALITY(1);
}
if (!reached2) {
uv2 += offset * QUALITY(1);
}
if (!reachedBoth) {
for (int i = 2; i < ITERATIONS; i++) {
if (!reached1) {
lumaEnd1 = rgb2luma(textureLod(source_color, uv1, 0.0).xyz * exposure * params.luminance_multiplier);
lumaEnd1 = lumaEnd1 - lumaLocalAverage;
}
if (!reached2) {
lumaEnd2 = rgb2luma(textureLod(source_color, uv2, 0.0).xyz * exposure * params.luminance_multiplier);
lumaEnd2 = lumaEnd2 - lumaLocalAverage;
}
reached1 = abs(lumaEnd1) >= gradientScaled;
reached2 = abs(lumaEnd2) >= gradientScaled;
reachedBoth = reached1 && reached2;
if (!reached1) {
uv1 -= offset * QUALITY(i);
}
if (!reached2) {
uv2 += offset * QUALITY(i);
}
if (reachedBoth) {
break;
}
}
}
float distance1 = isHorizontal ? (uv_interp.x - uv1.x) : (uv_interp.y - uv1.y);
float distance2 = isHorizontal ? (uv2.x - uv_interp.x) : (uv2.y - uv_interp.y);
bool isDirection1 = distance1 < distance2;
float distanceFinal = min(distance1, distance2);
float edgeThickness = (distance1 + distance2);
bool isLumaCenterSmaller = lumaCenter < lumaLocalAverage;
bool correctVariation1 = (lumaEnd1 < 0.0) != isLumaCenterSmaller;
bool correctVariation2 = (lumaEnd2 < 0.0) != isLumaCenterSmaller;
bool correctVariation = isDirection1 ? correctVariation1 : correctVariation2;
float pixelOffset = -distanceFinal / edgeThickness + 0.5;
float finalOffset = correctVariation ? pixelOffset : 0.0;
float lumaAverage = (1.0 / 12.0) * (2.0 * (lumaDownUp + lumaLeftRight) + lumaLeftCorners + lumaRightCorners);
float subPixelOffset1 = clamp(abs(lumaAverage - lumaCenter) / lumaRange, 0.0, 1.0);
float subPixelOffset2 = (-2.0 * subPixelOffset1 + 3.0) * subPixelOffset1 * subPixelOffset1;
float subPixelOffsetFinal = subPixelOffset2 * subPixelOffset2 * SUBPIXEL_QUALITY;
finalOffset = max(finalOffset, subPixelOffsetFinal);
vec2 finalUv = uv_interp;
if (isHorizontal) {
finalUv.y += finalOffset * stepLength;
} else {
finalUv.x += finalOffset * stepLength;
}
vec3 finalColor = textureLod(source_color, finalUv, 0.0).xyz * exposure * params.luminance_multiplier;
return finalColor;
#endif
}
// From https://alex.vlachos.com/graphics/Alex_Vlachos_Advanced_VR_Rendering_GDC2015.pdf
// and https://www.shadertoy.com/view/MslGR8 (5th one starting from the bottom)
// NOTE: `frag_coord` is in pixels (i.e. not normalized UV).
// This dithering must be applied after encoding changes (linear/nonlinear) have been applied
// as the final step before quantization from floating point to integer values.
vec3 screen_space_dither(vec2 frag_coord, float bit_alignment_diviser) {
// Iestyn's RGB dither (7 asm instructions) from Portal 2 X360, slightly modified for VR.
// Removed the time component to avoid passing time into this shader.
vec3 dither = vec3(dot(vec2(171.0, 231.0), frag_coord));
dither.rgb = fract(dither.rgb / vec3(103.0, 71.0, 97.0));
// Subtract 0.5 to avoid slightly brightening the whole viewport.
// Use a dither strength of 100% rather than the 37.5% suggested by the original source.
return (dither.rgb - 0.5) / bit_alignment_diviser;
}
void main() {
#ifdef USE_MULTIVIEW
vec4 color = textureLod(source_color, vec3(uv_interp, ViewIndex), 0.0f);
#else
vec4 color = textureLod(source_color, uv_interp, 0.0f);
#endif
color.rgb *= params.luminance_multiplier;
// Exposure
float exposure = params.exposure;
if (bool(params.flags & FLAG_USE_AUTO_EXPOSURE)) {
exposure *= 1.0 / (texelFetch(source_auto_exposure, ivec2(0, 0), 0).r * params.luminance_multiplier / params.auto_exposure_scale);
}
color.rgb *= exposure;
// Single-pass FXAA and pre-tonemap glow.
if (bool(params.flags & FLAG_USE_FXAA)) {
// FXAA must be performed before glow to preserve the "bleed" effect of glow.
color.rgb = do_fxaa(color.rgb, exposure, uv_interp);
}
if (bool(params.flags & FLAG_USE_GLOW) && params.glow_mode != GLOW_MODE_SOFTLIGHT) {
vec3 glow = gather_glow(source_glow, uv_interp) * params.glow_intensity;
if (params.glow_map_strength > 0.001) {
glow = mix(glow, texture(glow_map, uv_interp).rgb * glow, params.glow_map_strength);
}
if (params.glow_mode == GLOW_MODE_MIX) {
color.rgb = color.rgb * (1.0 - params.glow_intensity) + glow;
} else {
color.rgb = apply_glow(color.rgb, glow, params.white);
}
}
// Tonemap to lower dynamic range.
color.rgb = apply_tonemapping(color.rgb);
// Post-tonemap glow.
if (bool(params.flags & FLAG_USE_GLOW) && params.glow_mode == GLOW_MODE_SOFTLIGHT) {
// Apply soft light after tonemapping to mitigate the issue of discontinuity
// at 1.0 and higher. This makes the issue only appear with HDR output that
// can exceed a 1.0 output value.
vec3 glow = gather_glow(source_glow, uv_interp) * params.glow_intensity;
if (params.glow_map_strength > 0.001) {
glow = mix(glow, texture(glow_map, uv_interp).rgb * glow, params.glow_map_strength);
}
glow = apply_tonemapping(glow);
color.rgb = apply_glow(color.rgb, glow, params.white);
}
// Additional effects.
if (bool(params.flags & FLAG_USE_BCS)) {
// Apply brightness:
// Apply to relative luminance. This ensures that the hue and saturation of
// colors is not affected by the adjustment, but requires the multiplication
// to be performed on linear-encoded values.
color.rgb = color.rgb * params.bcs.x;
color.rgb = linear_to_srgb(color.rgb);
// Apply contrast:
// By applying contrast to RGB values that are perceptually uniform (nonlinear),
// the darkest values are not hard-clipped as badly, which produces a
// higher quality contrast adjustment and maintains compatibility with
// existing projects.
color.rgb = mix(vec3(0.5), color.rgb, params.bcs.y);
// Apply saturation:
// By applying saturation adjustment to nonlinear sRGB-encoded values with
// even weights the preceived brightness of blues are affected, but this
// maintains compatibility with existing projects.
color.rgb = mix(vec3(dot(vec3(1.0), color.rgb) * (1.0 / 3.0)), color.rgb, params.bcs.z);
if (bool(params.flags & FLAG_USE_COLOR_CORRECTION)) {
color.rgb = clamp(color.rgb, vec3(0.0), vec3(1.0));
color.rgb = apply_color_correction(color.rgb);
// When using color correction and FLAG_CONVERT_TO_SRGB is false, there
// is no need to convert back to linear because the color correction
// texture sampling does this for us.
} else if (!bool(params.flags & FLAG_CONVERT_TO_SRGB)) {
color.rgb = srgb_to_linear(color.rgb);
}
} else if (bool(params.flags & FLAG_CONVERT_TO_SRGB)) {
color.rgb = linear_to_srgb(color.rgb);
}
// Debanding should be done at the end of tonemapping, but before writing to the LDR buffer.
// Otherwise, we're adding noise to an already-quantized image.
if (bool(params.flags & FLAG_USE_8_BIT_DEBANDING)) {
// Divide by 255 to align to 8-bit quantization.
color.rgb += screen_space_dither(gl_FragCoord.xy, 255.0);
}
frag_color = color;
}
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