backends/drm: support arbitrary input transfer functions in the icc shader

src/backends/drm/drm_egl_layer_surface.cpp

@@ -183,7 +183,7 @@ bool EglGbmLayerSurface::endRendering(const QRegion &damagedRegion, OutputFrame
         GLFramebuffer::pushFramebuffer(fbo);
         ShaderBinder binder = m_surface->iccShader ? ShaderBinder(m_surface->iccShader->shader()) : ShaderBinder(ShaderTrait::MapTexture | ShaderTrait::TransformColorspace);
         if (m_surface->iccShader) {
-            m_surface->iccShader->setUniforms(m_surface->iccProfile, m_surface->intermediaryColorDescription.referenceLuminance(), m_surface->channelFactors);
+            m_surface->iccShader->setUniforms(m_surface->iccProfile, m_surface->intermediaryColorDescription, m_surface->channelFactors);
         } else {
             QMatrix4x4 ctm;
             ctm(0, 0) = m_surface->channelFactors.x();

src/backends/drm/icc.frag

@@ -1,5 +1,6 @@
 // SPDX-FileCopyrightText: 2023 Xaver Hugl <xaver.hugl@gmail.com>
 // SPDX-License-Identifier: GPL-2.0-or-later
+#include "colormanagement.glsl"
 precision highp float;
 precision highp sampler2D;
 precision highp sampler3D;
@@ -7,7 +8,6 @@ precision highp sampler3D;
 in vec2 texcoord0;
 
 uniform sampler2D src;
-uniform float referenceLuminance;
 
 uniform mat4 toXYZD50;
 
@@ -37,6 +37,7 @@ vec3 sample1DLut(vec3 input, sampler2D lut, int lutSize) {
 void main()
 {
     vec4 tex = texture2D(src, texcoord0);
+    tex = encodingToNits(tex, sourceNamedTransferFunction);
     tex.rgb /= max(tex.a, 0.001);
     tex.rgb /= referenceLuminance;
     tex.rgb = (toXYZD50 * vec4(tex.rgb, 1.0)).rgb;

src/backends/drm/icc_core.frag

@@ -1,6 +1,7 @@
 #version 140
 // SPDX-FileCopyrightText: 2023 Xaver Hugl <xaver.hugl@gmail.com>
 // SPDX-License-Identifier: GPL-2.0-or-later
+#include "colormanagement.glsl"
 precision highp float;
 precision highp sampler2D;
 precision highp sampler3D;
@@ -10,7 +11,6 @@ in vec2 texcoord0;
 out vec4 fragColor;
 
 uniform sampler2D src;
-uniform float referenceLuminance;
 
 uniform mat4 toXYZD50;
 
@@ -40,6 +40,7 @@ vec3 sample1DLut(in vec3 srcColor, in sampler2D lut, in int lutSize) {
 void main()
 {
     vec4 tex = texture(src, texcoord0);
+    tex = encodingToNits(tex, sourceNamedTransferFunction);
     tex.rgb /= max(tex.a, 0.001);
     tex.rgb /= referenceLuminance;
     tex.rgb = (toXYZD50 * vec4(tex.rgb, 1.0)).rgb;

src/backends/drm/icc_shader.cpp

@@ -22,6 +22,7 @@ IccShader::IccShader()
 {
     m_locations = {
         .src = m_shader->uniformLocation("src"),
+        .sourceNamedTransferFunction = m_shader->uniformLocation("sourceNamedTransferFunction"),
         .referenceLuminance = m_shader->uniformLocation("referenceLuminance"),
         .toXYZD50 = m_shader->uniformLocation("toXYZD50"),
         .bsize = m_shader->uniformLocation("Bsize"),
@@ -145,7 +146,7 @@ GLShader *IccShader::shader() const
     return m_shader.get();
 }
 
-void IccShader::setUniforms(const std::shared_ptr<IccProfile> &profile, float referenceLuminance, const QVector3D &channelFactors)
+void IccShader::setUniforms(const std::shared_ptr<IccProfile> &profile, const ColorDescription &inputColor, const QVector3D &channelFactors)
 {
     // this failing can be silently ignored, it should only happen with GPU resets and gets corrected later
     setProfile(profile);
@@ -155,7 +156,8 @@ void IccShader::setUniforms(const std::shared_ptr<IccProfile> &profile, float re
     nightColor(1, 1) = channelFactors.y();
     nightColor(2, 2) = channelFactors.z();
     m_shader->setUniform(m_locations.toXYZD50, m_toXYZD50 * nightColor);
-    m_shader->setUniform(m_locations.referenceLuminance, referenceLuminance);
+    m_shader->setUniform(m_locations.sourceNamedTransferFunction, inputColor.transferFunction().type);
+    m_shader->setUniform(m_locations.referenceLuminance, inputColor.referenceLuminance());
 
     glActiveTexture(GL_TEXTURE1);
     if (m_B) {

src/backends/drm/icc_shader.h

@@ -4,6 +4,7 @@
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 #pragma once
+#include "core/colorspace.h"
 
 #include <QMatrix4x4>
 #include <QSizeF>
@@ -25,7 +26,7 @@ public:
     ~IccShader();
 
     GLShader *shader() const;
-    void setUniforms(const std::shared_ptr<IccProfile> &profile, float referenceLuminance, const QVector3D &channelFactors);
+    void setUniforms(const std::shared_ptr<IccProfile> &profile, const ColorDescription &inputColor, const QVector3D &channelFactors);
 
 private:
     bool setProfile(const std::shared_ptr<IccProfile> &profile);
@@ -42,6 +43,7 @@ private:
     struct Locations
     {
         int src;
+        int sourceNamedTransferFunction;
         int referenceLuminance;
         int toXYZD50;
         int bsize;

src/opengl/glshader.cpp

@@ -307,6 +307,12 @@ bool GLShader::setUniform(const char *name, float value)
     return setUniform(location, value);
 }
 
+bool GLShader::setUniform(const char *name, double value)
+{
+    const int location = uniformLocation(name);
+    return setUniform(location, value);
+}
+
 bool GLShader::setUniform(const char *name, int value)
 {
     const int location = uniformLocation(name);
@@ -357,6 +363,14 @@ bool GLShader::setUniform(int location, float value)
     return (location >= 0);
 }
 
+bool GLShader::setUniform(int location, double value)
+{
+    if (location >= 0) {
+        glUniform1f(location, value);
+    }
+    return (location >= 0);
+}
+
 bool GLShader::setUniform(int location, int value)
 {
     if (location >= 0) {

src/opengl/glshader.h

@@ -46,6 +46,7 @@ public:
     int uniformLocation(const char *name);
 
     bool setUniform(const char *name, float value);
+    bool setUniform(const char *name, double value);
     bool setUniform(const char *name, int value);
     bool setUniform(const char *name, const QVector2D &value);
     bool setUniform(const char *name, const QVector3D &value);
@@ -55,6 +56,7 @@ public:
     bool setUniform(const char *name, const QColor &color);
 
     bool setUniform(int location, float value);
+    bool setUniform(int location, double value);
     bool setUniform(int location, int value);
     bool setUniform(int location, int xValue, int yValue, int zValue);
     bool setUniform(int location, const QVector2D &value);