gpu: Make glTexSubImage2D work with GL_SRGB_ALPHA on OpenGL

gpu/command_buffer/tests/gl_ext_srgb_unittest.cc

Index: gpu/command_buffer/tests/gl_ext_srgb_unittest.cc
diff --git a/gpu/command_buffer/tests/gl_ext_srgb_unittest.cc b/gpu/command_buffer/tests/gl_ext_srgb_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..53b3c24fc3d4d2a260d0ddb4f0745f3def90c417
--- /dev/null
+++ b/gpu/command_buffer/tests/gl_ext_srgb_unittest.cc
@@ -0,0 +1,74 @@
+// Copyright (c) 2015 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 <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
+
+#include "gpu/command_buffer/tests/gl_manager.h"
+#include "gpu/command_buffer/tests/gl_test_utils.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace gpu {
+
+// A collection of tests that exercise the GL_EXT_srgb extension.
+class GLEXTSRGBTest : public testing::Test {
+ protected:
+  void SetUp() override { gl_.Initialize(GLManager::Options()); }
+  void TearDown() override { gl_.Destroy(); }
+  bool IsApplicable() const {
+    return GLTestHelper::HasExtension("GL_EXT_sRGB");
+  }
+  GLManager gl_;
+};
+
+// Test to ensure that GL_SRGB_ALPHA as glTex(Sub)Image2D parameter works. This
+// is tricky because GL_SRGB_ALPHA is valid in OpenGL ES 2.0 but not valid in
+// OpenGL.
+TEST_F(GLEXTSRGBTest, TexImageSRGBALPHAFormat) {
+  if (!IsApplicable())
+    return;
+  static const int kWidth = 10;
+  static const int kHeight = 10;
+  static const int kSubImageX = kWidth / 2;
+  static const int kSubImageY = kHeight / 2;
+  static const int kSubImageWidth = kWidth / 2;
+  static const int kSubImageHeight = kHeight / 2;
+  static const uint8 kImageColor[] = {255, 255, 255, 255};
+  static const uint8 kSubImageColor[] = {128, 128, 128, 128};
+
+  uint8 pixels[kWidth * kHeight * 4];
+
+  GLuint tex = 0;
+  glGenTextures(1, &tex);
+  glBindTexture(GL_TEXTURE_2D, tex);
+  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+
+  memset(pixels, kImageColor[0], sizeof(pixels));
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB_ALPHA_EXT, kWidth, kHeight, 0,
+               GL_SRGB_ALPHA_EXT, GL_UNSIGNED_BYTE, pixels);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  memset(pixels, kSubImageColor[0], sizeof(pixels));
+  glTexSubImage2D(GL_TEXTURE_2D, 0, kSubImageX, kSubImageY, kSubImageWidth,
+                  kSubImageHeight, GL_SRGB_ALPHA_EXT, GL_UNSIGNED_BYTE, pixels);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  glBindTexture(GL_TEXTURE_2D, 0);
+  GLuint fbo = 0;
+  glGenFramebuffers(1, &fbo);
+  glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+                         tex, 0);
+  EXPECT_EQ(static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE),
+            glCheckFramebufferStatus(GL_FRAMEBUFFER));
+
+  GLTestHelper::CheckPixels(0, 0, kSubImageX, kHeight, 0, kImageColor);
+  GLTestHelper::CheckPixels(0, 0, kWidth, kSubImageY, 0, kImageColor);
+  GLTestHelper::CheckPixels(kSubImageX, kSubImageY, kSubImageWidth,
+                            kSubImageHeight, 0, kSubImageColor);
+}
+
+}  // namespace gpu