cc: Add pixel tests for transfer function shaders

ui/gfx/color_transform_unittest.cc

 // Copyright (c) 2016 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 "base/logging.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/color_space.h"
 #include "ui/gfx/color_transform.h"
 #include "ui/gfx/icc_profile.h"
 #include "ui/gfx/test/icc_profiles.h"
@@ skipping 382 matching lines @@
 #endif
 TEST(SimpleColorSpace, MAYBE_SampleShaderSource) {
   ColorSpace bt709 = ColorSpace::CreateREC709();
   ColorSpace output(ColorSpace::PrimaryID::BT2020,
                     ColorSpace::TransferID::GAMMA28);
   std::string source =
       ColorTransform::NewColorTransform(
           bt709, output, ColorTransform::Intent::INTENT_PERCEPTUAL)
           ->GetShaderSource();
   std::string expected =
+      "float TransferFn1(float v) {\n"
+      "  if (v < 4.04499359e-02)\n"
+      "    return 7.73993805e-02 * v;\n"
+      "  return pow(9.47867334e-01 * v + 5.21326549e-02, 2.40000010e+00);\n"
+      "}\n"
+      "float TransferFn3(float v) {\n"
+      "  return pow(v, 3.57142866e-01);\n"
+      "}\n"
       "vec3 DoColorConversion(vec3 color) {\n"
       "  color = mat3(1.16438353e+00, 1.16438353e+00, 1.16438353e+00,\n"
       "               -2.28029018e-09, -2.13248596e-01, 2.11240172e+00,\n"
       "               1.79274118e+00, -5.32909274e-01, -5.96049432e-10) "
       "* color;\n"
       "  color += vec3(-9.69429970e-01, 3.00019622e-01, -1.12926030e+00);\n"
-      "  if (color.r < 4.04499359e-02)\n"
-      "    color.r = 7.73993805e-02 * color.r;\n"
-      "  else\n"
-      "    color.r = pow(9.47867334e-01 * color.r + 5.21326549e-02, "
-      "2.40000010e+00);\n"
-      "  if (color.g < 4.04499359e-02)\n"
-      "    color.g = 7.73993805e-02 * color.g;\n"
-      "  else\n"
-      "    color.g = pow(9.47867334e-01 * color.g + 5.21326549e-02, "
-      "2.40000010e+00);\n"
-      "  if (color.b < 4.04499359e-02)\n"
-      "    color.b = 7.73993805e-02 * color.b;\n"
-      "  else\n"
-      "    color.b = pow(9.47867334e-01 * color.b + 5.21326549e-02, "
-      "2.40000010e+00);\n"
+      "  color.r = TransferFn1(color.r);\n"
+      "  color.g = TransferFn1(color.g);\n"
+      "  color.b = TransferFn1(color.b);\n"
       "  color = mat3(6.27403915e-01, 6.90973178e-02, 1.63914412e-02,\n"
       "               3.29283148e-01, 9.19540286e-01, 8.80132914e-02,\n"
       "               4.33131084e-02, 1.13623003e-02, 8.95595253e-01) "
       "* color;\n"
-      "  color.r = pow(color.r, 3.57142866e-01);\n"
-      "  color.g = pow(color.g, 3.57142866e-01);\n"
-      "  color.b = pow(color.b, 3.57142866e-01);\n"
+      "  color.r = TransferFn3(color.r);\n"
+      "  color.g = TransferFn3(color.g);\n"
+      "  color.b = TransferFn3(color.b);\n"
       "  return color;\n"
       "}\n";
   EXPECT_EQ(source, expected);
 }
 
 class TransferTest : public testing::TestWithParam<ColorSpace::TransferID> {};
 
 TEST_P(TransferTest, basicTest) {
   gfx::ColorSpace space_with_transfer(ColorSpace::PrimaryID::BT709, GetParam(),
                                       ColorSpace::MatrixID::RGB,
@@ skipping 124 matching lines @@
 
 INSTANTIATE_TEST_CASE_P(
     C,
     ColorSpaceTest,
     testing::Combine(testing::ValuesIn(all_primaries),
                      testing::Values(ColorSpace::TransferID::BT709),
                      testing::ValuesIn(all_matrices),
                      testing::ValuesIn(all_ranges),
                      testing::ValuesIn(intents)));
 }  // namespace