cc: Add analytic color conversion to shaders

cc/output/shader.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/output/shader.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <vector>
@@ skipping 431 matching lines @@
         uniforms.push_back("resource_offset");
       } else {
         uniforms.push_back("yuv_matrix");
         uniforms.push_back("yuv_adj");
       }
       break;
     case INPUT_COLOR_SOURCE_UNIFORM:
       uniforms.push_back("color");
       break;
   }
+  if (color_conversion_mode_ == COLOR_CONVERSION_MODE_ANALYTIC) {
+    uniforms.push_back("color_src_to_dst_primary_matrix");
+    uniforms.push_back("color_src_to_linear_tr_fn");
+    uniforms.push_back("color_linear_to_dst_tr_fn");
+  }
 
   locations.resize(uniforms.size());
 
   GetProgramUniformLocations(context, program, uniforms.size(), uniforms.data(),
                              locations.data(), base_uniform_index);
 
   size_t index = 0;
   if (has_blend_mode()) {
     backdrop_location_ = locations[index++];
     original_backdrop_location_ = locations[index++];
@@ skipping 37 matching lines @@
         resource_offset_location_ = locations[index++];
       } else {
         yuv_matrix_location_ = locations[index++];
         yuv_adj_location_ = locations[index++];
       }
       break;
     case INPUT_COLOR_SOURCE_UNIFORM:
       color_location_ = locations[index++];
       break;
   }
+  if (color_conversion_mode_ == COLOR_CONVERSION_MODE_ANALYTIC) {
+    color_src_to_dst_primary_matrix_location_ = locations[index++];
+    color_src_to_linear_tr_fn_location_ = locations[index++];
+    color_linear_to_dst_tr_fn_location_ = locations[index++];
+  }
   DCHECK_EQ(index, locations.size());
 }
 
 std::string FragmentShader::SetBlendModeFunctions(
     const std::string& shader_string) const {
   if (shader_string.find("ApplyBlendMode") == std::string::npos)
     return shader_string;
 
   if (!has_blend_mode()) {
     return "#define ApplyBlendMode(X, Y) (X)\n" + shader_string;
@@ skipping 372 matching lines @@
       SRC("vec4 texColor = vec4(yuv2rgb(yuv), 1.0);");
       break;
     case INPUT_COLOR_SOURCE_UNIFORM:
       DCHECK(!ignore_sampler_type_);
       DCHECK(!has_rgba_fragment_tex_transform_);
       HDR("uniform vec4 color;");
       SRC("// Uniform color");
       SRC("vec4 texColor = color;");
       break;
   }
+
+  // Apply color conversion
+  if (color_conversion_mode_ == COLOR_CONVERSION_MODE_ANALYTIC) {
+    HDR("uniform mat3 color_src_to_dst_primary_matrix;");
+    HDR("// Transfer function parameter uniforms. Parameters are based on");
+    HDR("// SkColorSpaceTransferFn (as fA at index 0 through fG at index 6).");
+    HDR("uniform float color_src_to_linear_tr_fn[7];");
+    HDR("uniform float color_linear_to_dst_tr_fn[7];");
+    HDR("float TransferFn(float x, float params[7]) {");
+    HDR("  x = clamp(x, 0.0, 1.0);");
+    HDR("  if (x < params[3])");
+    HDR("    return params[2]*x + params[5];");
+    HDR("  return pow(params[0] * x + params[1], params[6]) + params[4];");
+    HDR("}");
+    SRC("// Apply color conversion");
+    SRC("texColor.r = TransferFn(texColor.x, color_src_to_linear_tr_fn);");
+    SRC("texColor.g = TransferFn(texColor.y, color_src_to_linear_tr_fn);");
+    SRC("texColor.b = TransferFn(texColor.z, color_src_to_linear_tr_fn);");
+    SRC("texColor.rgb = color_src_to_dst_primary_matrix * texColor.rgb;");
+    SRC("texColor.r = TransferFn(texColor.x, color_linear_to_dst_tr_fn);");
+    SRC("texColor.g = TransferFn(texColor.y, color_linear_to_dst_tr_fn);");
+    SRC("texColor.b = TransferFn(texColor.z, color_linear_to_dst_tr_fn);");
+  }
+
   // Apply the color matrix to texColor.
   if (has_color_matrix_) {
     HDR("uniform mat4 colorMatrix;");
     HDR("uniform vec4 colorOffset;");
     SRC("// Apply color matrix");
     SRC("float nonZeroAlpha = max(texColor.a, 0.00001);");
     SRC("texColor = vec4(texColor.rgb / nonZeroAlpha, nonZeroAlpha);");
     SRC("texColor = colorMatrix * texColor + colorOffset;");
     SRC("texColor.rgb *= texColor.a;");
     SRC("texColor = clamp(texColor, 0.0, 1.0);");
@@ skipping 83 matching lines @@
       else
         SRC("gl_FragColor = ApplyBlendMode(texColor, 0.0);");
       break;
   }
   source += "}\n";
 
   return header + source;
 }
 
 }  // namespace cc