commit 3c51bc5024b849c9ed5defbea058133399cdda3e
author Alec Mouri <alecmouri@google.com> Fri Nov 04 01:28:55 2022 +0000
committer Alec Mouri <alecmouri@google.com> Sat Nov 05 00:58:18 2022 +0000
tree a0f32a4912315cf647a33ec9b6624751c62f707f
parent 89ea6a91e3ceb2abbc6cfce890dd622c7e219dbb

Improve tonemapping utilities

* Add util for getting buffer dataspace from metadata, since some
  ANativeWindow queries are unreliable when Surface endpoints are passed
  between processes, e.g., camera
* Let libshaders generate SkSL for SkColorFilters

Bug: 238395777
Test: Switching HDR cameras don't color shift
Change-Id: I7c3b917eeafcf8d028f8f52f38aa1389025bc607

libs/shaders/include/shaders/shaders.h

diff --git a/libs/shaders/include/shaders/shaders.h b/libs/shaders/include/shaders/shaders.h
index 2a4a370..42b0cc1 100644
--- a/libs/shaders/include/shaders/shaders.h
+++ b/libs/shaders/include/shaders/shaders.h
@@ -68,6 +68,9 @@
     // fakeInputDataspace is used to essentially masquerade the input dataspace to be the output
     // dataspace for correct conversion to linear colors.
     ui::Dataspace fakeInputDataspace = ui::Dataspace::UNKNOWN;
+
+    enum SkSLType { Shader, ColorFilter };
+    SkSLType type = Shader;
 };
 
 static inline bool operator==(const LinearEffect& lhs, const LinearEffect& rhs) {
@@ -96,6 +99,10 @@
 // 2. Apply color transform matrices in linear space
 std::string buildLinearEffectSkSL(const LinearEffect& linearEffect);
 
+// Generates a shader string that applies color transforms in linear space.
+// This is intended to be plugged into an SkColorFilter
+std::string buildLinearEffectSkSLForColorFilter(const LinearEffect& linearEffect);
+
 // Generates a list of uniforms to set on the LinearEffect shader above.
 std::vector<tonemap::ShaderUniform> buildLinearEffectUniforms(
         const LinearEffect& linearEffect, const mat4& colorTransform, float maxDisplayLuminance,

libs/shaders/shaders.cpp

diff --git a/libs/shaders/shaders.cpp b/libs/shaders/shaders.cpp
index f80e93f..a3c403e 100644
--- a/libs/shaders/shaders.cpp
+++ b/libs/shaders/shaders.cpp
@@ -386,12 +386,23 @@
     }
 }
 
-void generateEffectiveOOTF(bool undoPremultipliedAlpha, std::string& shader) {
-    shader.append(R"(
-        uniform shader child;
-        half4 main(float2 xy) {
-            float4 c = float4(child.eval(xy));
-    )");
+void generateEffectiveOOTF(bool undoPremultipliedAlpha, LinearEffect::SkSLType type,
+                           std::string& shader) {
+    switch (type) {
+        case LinearEffect::SkSLType::ColorFilter:
+            shader.append(R"(
+                half4 main(half4 inputColor) {
+                    float4 c = float4(inputColor);
+            )");
+            break;
+        case LinearEffect::SkSLType::Shader:
+            shader.append(R"(
+                uniform shader child;
+                half4 main(float2 xy) {
+                    float4 c = float4(child.eval(xy));
+            )");
+            break;
+    }
     if (undoPremultipliedAlpha) {
         shader.append(R"(
             c.rgb = c.rgb / (c.a + 0.0019);
@@ -459,7 +470,7 @@
     generateXYZTransforms(shaderString);
     generateOOTF(linearEffect.inputDataspace, linearEffect.outputDataspace, shaderString);
     generateOETF(linearEffect.outputDataspace, shaderString);
-    generateEffectiveOOTF(linearEffect.undoPremultipliedAlpha, shaderString);
+    generateEffectiveOOTF(linearEffect.undoPremultipliedAlpha, linearEffect.type, shaderString);
     return shaderString;
 }