xref: /external/chromium_org/gpu/command_buffer/tests/gl_copy_texture_CHROMIUM_unittest.cc

// Copyright (c) 2012 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.

#ifndef GL_GLEXT_PROTOTYPES
#define GL_GLEXT_PROTOTYPES
#endif

#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>
#include <GLES2/gl2extchromium.h>

#include "gpu/command_buffer/tests/gl_manager.h"
#include "gpu/command_buffer/tests/gl_test_utils.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace gpu {

// A collection of tests that exercise the GL_CHROMIUM_copy_texture extension.
class GLCopyTextureCHROMIUMTest : public testing::Test {
 protected:
  virtual void SetUp() {
    gl_.Initialize(GLManager::Options());

    glGenTextures(2, textures_);
    glBindTexture(GL_TEXTURE_2D, textures_[1]);

    // Some drivers (NVidia/SGX) require texture settings to be a certain way or
    // they won't report FRAMEBUFFER_COMPLETE.
    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);

    glGenFramebuffers(1, &framebuffer_id_);
    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer_id_);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                           textures_[1], 0);
  }

  virtual void TearDown() {
    glDeleteTextures(2, textures_);
    glDeleteFramebuffers(1, &framebuffer_id_);
    gl_.Destroy();
  }

  GLManager gl_;
  GLuint textures_[2];
  GLuint framebuffer_id_;
};

// Test to ensure that the basic functionality of the extension works.
TEST_F(GLCopyTextureCHROMIUMTest, Basic) {
  uint8 pixels[1 * 4] = { 255u, 0u, 0u, 255u };

  glBindTexture(GL_TEXTURE_2D, textures_[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE,
               pixels);

  glCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1], 0, GL_RGBA,
                        GL_UNSIGNED_BYTE);
  EXPECT_TRUE(glGetError() == GL_NO_ERROR);

  // Check the FB is still bound.
  GLint value = 0;
  glGetIntegerv(GL_FRAMEBUFFER_BINDING, &value);
  GLuint fb_id = value;
  EXPECT_EQ(framebuffer_id_, fb_id);

  // Check that FB is complete.
  EXPECT_EQ(static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE),
            glCheckFramebufferStatus(GL_FRAMEBUFFER));

  GLTestHelper::CheckPixels(0, 0, 1, 1, 0, pixels);
  EXPECT_TRUE(GL_NO_ERROR == glGetError());
}

// Test that the extension respects the flip-y pixel storage setting.
TEST_F(GLCopyTextureCHROMIUMTest, FlipY) {
  uint8 pixels[2][2][4];
  for (int x = 0; x < 2; ++x) {
    for (int y = 0; y < 2; ++y) {
      pixels[y][x][0] = x + y;
      pixels[y][x][1] = x + y;
      pixels[y][x][2] = x + y;
      pixels[y][x][3] = 255u;
    }
  }

  glBindTexture(GL_TEXTURE_2D, textures_[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE,
               pixels);

  glPixelStorei(GL_UNPACK_FLIP_Y_CHROMIUM, GL_TRUE);
  glCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1], 0, GL_RGBA,
                        GL_UNSIGNED_BYTE);
  EXPECT_TRUE(GL_NO_ERROR == glGetError());

  uint8 copied_pixels[2][2][4] = {{{0}}};
  glReadPixels(0, 0, 2, 2, GL_RGBA, GL_UNSIGNED_BYTE, copied_pixels);
  for (int x = 0; x < 2; ++x) {
    for (int y = 0; y < 2; ++y) {
      EXPECT_EQ(pixels[1-y][x][0], copied_pixels[y][x][0]);
      EXPECT_EQ(pixels[1-y][x][1], copied_pixels[y][x][1]);
      EXPECT_EQ(pixels[1-y][x][2], copied_pixels[y][x][2]);
      EXPECT_EQ(pixels[1-y][x][3], copied_pixels[y][x][3]);
    }
  }

  EXPECT_TRUE(GL_NO_ERROR == glGetError());
}

// Test that the extension respects the GL_UNPACK_PREMULTIPLY_ALPHA_CHROMIUM
// storage setting.
TEST_F(GLCopyTextureCHROMIUMTest, PremultiplyAlpha) {
  uint8 pixels[1 * 4] = { 2, 2, 2, 128 };

  glBindTexture(GL_TEXTURE_2D, textures_[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE,
               pixels);

  glPixelStorei(GL_UNPACK_PREMULTIPLY_ALPHA_CHROMIUM, GL_TRUE);
  glCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1], 0, GL_RGBA,
                       GL_UNSIGNED_BYTE);
  EXPECT_TRUE(GL_NO_ERROR == glGetError());

  uint8 copied_pixels[1 * 4] = {0};
  glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, copied_pixels);
  EXPECT_EQ(1u, copied_pixels[0]);
  EXPECT_EQ(1u, copied_pixels[1]);
  EXPECT_EQ(1u, copied_pixels[2]);
  EXPECT_EQ(128u, copied_pixels[3]);

  EXPECT_TRUE(GL_NO_ERROR == glGetError());
}

// Test that the extension respects the GL_UNPACK_UNPREMULTIPLY_ALPHA_CHROMIUM
// storage setting.
TEST_F(GLCopyTextureCHROMIUMTest, UnpremultiplyAlpha) {
  uint8 pixels[1 * 4] = { 16, 16, 16, 128 };

  glBindTexture(GL_TEXTURE_2D, textures_[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE,
               pixels);

  glPixelStorei(GL_UNPACK_UNPREMULTIPLY_ALPHA_CHROMIUM, GL_TRUE);
  glCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1], 0, GL_RGBA,
                        GL_UNSIGNED_BYTE);
  EXPECT_TRUE(GL_NO_ERROR == glGetError());

  uint8 copied_pixels[1 * 4] = {0};
  glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, copied_pixels);
  EXPECT_EQ(32u, copied_pixels[0]);
  EXPECT_EQ(32u, copied_pixels[1]);
  EXPECT_EQ(32u, copied_pixels[2]);
  EXPECT_EQ(128u, copied_pixels[3]);

  EXPECT_TRUE(GL_NO_ERROR == glGetError());
}

TEST_F(GLCopyTextureCHROMIUMTest, FlipYAndPremultiplyAlpha) {
  uint8 pixels[2][2][4];
  for (int x = 0; x < 2; ++x) {
    for (int y = 0; y < 2; ++y) {
      uint8 color = 16 * x + 16 * y;
      pixels[y][x][0] = color;
      pixels[y][x][1] = color;
      pixels[y][x][2] = color;
      pixels[y][x][3] = 128u;
    }
  }

  glBindTexture(GL_TEXTURE_2D, textures_[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE,
               pixels);

  glPixelStorei(GL_UNPACK_FLIP_Y_CHROMIUM, GL_TRUE);
  glPixelStorei(GL_UNPACK_PREMULTIPLY_ALPHA_CHROMIUM, GL_TRUE);
  glCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1], 0, GL_RGBA,
                        GL_UNSIGNED_BYTE);
  EXPECT_TRUE(GL_NO_ERROR == glGetError());

  uint8 copied_pixels[2][2][4] = {{{0}}};
  glReadPixels(0, 0, 2, 2, GL_RGBA, GL_UNSIGNED_BYTE, copied_pixels);
  for (int x = 0; x < 2; ++x) {
    for (int y = 0; y < 2; ++y) {
      EXPECT_EQ(pixels[1-y][x][0] / 2, copied_pixels[y][x][0]);
      EXPECT_EQ(pixels[1-y][x][1] / 2, copied_pixels[y][x][1]);
      EXPECT_EQ(pixels[1-y][x][2] / 2, copied_pixels[y][x][2]);
      EXPECT_EQ(pixels[1-y][x][3], copied_pixels[y][x][3]);
    }
  }

  EXPECT_TRUE(GL_NO_ERROR == glGetError());
}

TEST_F(GLCopyTextureCHROMIUMTest, FlipYAndUnpremultiplyAlpha) {
  uint8 pixels[2][2][4];
  for (int x = 0; x < 2; ++x) {
    for (int y = 0; y < 2; ++y) {
      uint8 color = 16 * x + 16 * y;
      pixels[y][x][0] = color;
      pixels[y][x][1] = color;
      pixels[y][x][2] = color;
      pixels[y][x][3] = 128u;
    }
  }

  glBindTexture(GL_TEXTURE_2D, textures_[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE,
               pixels);

  glPixelStorei(GL_UNPACK_FLIP_Y_CHROMIUM, GL_TRUE);
  glPixelStorei(GL_UNPACK_UNPREMULTIPLY_ALPHA_CHROMIUM, GL_TRUE);
  glCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1], 0, GL_RGBA,
                        GL_UNSIGNED_BYTE);
  EXPECT_TRUE(GL_NO_ERROR == glGetError());

  uint8 copied_pixels[2][2][4] = {{{0}}};
  glReadPixels(0, 0, 2, 2, GL_RGBA, GL_UNSIGNED_BYTE, copied_pixels);
  for (int x = 0; x < 2; ++x) {
    for (int y = 0; y < 2; ++y) {
      EXPECT_EQ(pixels[1-y][x][0] * 2, copied_pixels[y][x][0]);
      EXPECT_EQ(pixels[1-y][x][1] * 2, copied_pixels[y][x][1]);
      EXPECT_EQ(pixels[1-y][x][2] * 2, copied_pixels[y][x][2]);
      EXPECT_EQ(pixels[1-y][x][3], copied_pixels[y][x][3]);
    }
  }

  EXPECT_TRUE(GL_NO_ERROR == glGetError());
}

namespace {

void glEnableDisable(GLint param, GLboolean value) {
  if (value)
    glEnable(param);
  else
    glDisable(param);
}

}  // unnamed namespace

// Validate that some basic GL state is not touched upon execution of
// the extension.
TEST_F(GLCopyTextureCHROMIUMTest, BasicStatePreservation) {
  uint8 pixels[1 * 4] = { 255u, 0u, 0u, 255u };

  glBindFramebuffer(GL_FRAMEBUFFER, 0);

  glBindTexture(GL_TEXTURE_2D, textures_[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE,
               pixels);

  GLboolean reference_settings[2] = { GL_TRUE, GL_FALSE };
  for (int x = 0; x < 2; ++x) {
    GLboolean setting = reference_settings[x];
    glEnableDisable(GL_DEPTH_TEST, setting);
    glEnableDisable(GL_SCISSOR_TEST, setting);
    glEnableDisable(GL_STENCIL_TEST, setting);
    glEnableDisable(GL_CULL_FACE, setting);
    glEnableDisable(GL_BLEND, setting);
    glColorMask(setting, setting, setting, setting);
    glDepthMask(setting);

    glActiveTexture(GL_TEXTURE1 + x);

    glCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1], 0,
                          GL_RGBA, GL_UNSIGNED_BYTE);
    EXPECT_TRUE(GL_NO_ERROR == glGetError());

    EXPECT_EQ(setting, glIsEnabled(GL_DEPTH_TEST));
    EXPECT_EQ(setting, glIsEnabled(GL_SCISSOR_TEST));
    EXPECT_EQ(setting, glIsEnabled(GL_STENCIL_TEST));
    EXPECT_EQ(setting, glIsEnabled(GL_CULL_FACE));
    EXPECT_EQ(setting, glIsEnabled(GL_BLEND));

    GLboolean bool_array[4] = { GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE };
    glGetBooleanv(GL_DEPTH_WRITEMASK, bool_array);
    EXPECT_EQ(setting, bool_array[0]);

    bool_array[0] = GL_FALSE;
    glGetBooleanv(GL_COLOR_WRITEMASK, bool_array);
    EXPECT_EQ(setting, bool_array[0]);
    EXPECT_EQ(setting, bool_array[1]);
    EXPECT_EQ(setting, bool_array[2]);
    EXPECT_EQ(setting, bool_array[3]);

    GLint active_texture = 0;
    glGetIntegerv(GL_ACTIVE_TEXTURE, &active_texture);
    EXPECT_EQ(GL_TEXTURE1 + x, active_texture);
  }

  EXPECT_TRUE(GL_NO_ERROR == glGetError());
};

// Verify that invocation of the extension does not modify the bound
// texture state.
TEST_F(GLCopyTextureCHROMIUMTest, TextureStatePreserved) {
  // Setup the texture used for the extension invocation.
  uint8 pixels[1 * 4] = { 255u, 0u, 0u, 255u };
  glBindTexture(GL_TEXTURE_2D, textures_[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE,
               pixels);

  GLuint texture_ids[2];
  glGenTextures(2, texture_ids);

  glActiveTexture(GL_TEXTURE0);
  glBindTexture(GL_TEXTURE_2D, texture_ids[0]);

  glActiveTexture(GL_TEXTURE1);
  glBindTexture(GL_TEXTURE_2D, texture_ids[1]);

  glCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1], 0,
                        GL_RGBA, GL_UNSIGNED_BYTE);
  EXPECT_TRUE(GL_NO_ERROR == glGetError());

  GLint active_texture = 0;
  glGetIntegerv(GL_ACTIVE_TEXTURE, &active_texture);
  EXPECT_EQ(GL_TEXTURE1, active_texture);

  GLint bound_texture = 0;
  glGetIntegerv(GL_TEXTURE_BINDING_2D, &bound_texture);
  EXPECT_EQ(texture_ids[1], static_cast<GLuint>(bound_texture));
  glBindTexture(GL_TEXTURE_2D, 0);

  bound_texture = 0;
  glActiveTexture(GL_TEXTURE0);
  glGetIntegerv(GL_TEXTURE_BINDING_2D, &bound_texture);
  EXPECT_EQ(texture_ids[0], static_cast<GLuint>(bound_texture));
  glBindTexture(GL_TEXTURE_2D, 0);

  glDeleteTextures(2, texture_ids);

  EXPECT_TRUE(GL_NO_ERROR == glGetError());
}

// Verify that invocation of the extension does not perturb the currently
// bound FBO state.
TEST_F(GLCopyTextureCHROMIUMTest, FBOStatePreserved) {
  // Setup the texture used for the extension invocation.
  uint8 pixels[1 * 4] = { 255u, 0u, 0u, 255u };
  glBindTexture(GL_TEXTURE_2D, textures_[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE,
               pixels);

  GLuint texture_id;
  glGenTextures(1, &texture_id);
  glBindTexture(GL_TEXTURE_2D, texture_id);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE,
               0);

  GLuint renderbuffer_id;
  glGenRenderbuffers(1, &renderbuffer_id);
  glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer_id);
  glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, 1, 1);

  GLuint framebuffer_id;
  glGenFramebuffers(1, &framebuffer_id);
  glBindFramebuffer(GL_FRAMEBUFFER, framebuffer_id);
  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                         texture_id, 0);
  glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
                            GL_RENDERBUFFER, renderbuffer_id);
  EXPECT_TRUE(
      GL_FRAMEBUFFER_COMPLETE == glCheckFramebufferStatus(GL_FRAMEBUFFER));

  // Test that we can write to the bound framebuffer
  uint8 expected_color[4] = { 255u, 255u, 0, 255u };
  glClearColor(1.0, 1.0, 0, 1.0);
  glClear(GL_COLOR_BUFFER_BIT);
  GLTestHelper::CheckPixels(0, 0, 1, 1, 0, expected_color);

  glCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1], 0,
                        GL_RGBA, GL_UNSIGNED_BYTE);
  EXPECT_TRUE(GL_NO_ERROR == glGetError());

  EXPECT_TRUE(glIsFramebuffer(framebuffer_id));

  // Ensure that reading from the framebuffer produces correct pixels.
  GLTestHelper::CheckPixels(0, 0, 1, 1, 0, expected_color);

  uint8 expected_color2[4] = { 255u, 0, 255u, 255u };
  glClearColor(1.0, 0, 1.0, 1.0);
  glClear(GL_COLOR_BUFFER_BIT);
  GLTestHelper::CheckPixels(0, 0, 1, 1, 0, expected_color2);

  GLint bound_fbo = 0;
  glGetIntegerv(GL_FRAMEBUFFER_BINDING, &bound_fbo);
  EXPECT_EQ(framebuffer_id, static_cast<GLuint>(bound_fbo));

  GLint fbo_params = 0;
  glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                        GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE,
                                        &fbo_params);
  EXPECT_EQ(GL_TEXTURE, fbo_params);

  fbo_params = 0;
  glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                        GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME,
                                        &fbo_params);
  EXPECT_EQ(texture_id, static_cast<GLuint>(fbo_params));

  fbo_params = 0;
  glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
                                        GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE,
                                        &fbo_params);
  EXPECT_EQ(GL_RENDERBUFFER, fbo_params);

  fbo_params = 0;
  glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
                                        GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME,
                                        &fbo_params);
  EXPECT_EQ(renderbuffer_id, static_cast<GLuint>(fbo_params));

  glDeleteRenderbuffers(1, &renderbuffer_id);
  glDeleteTextures(1, &texture_id);
  glDeleteFramebuffers(1, &framebuffer_id);

  EXPECT_TRUE(GL_NO_ERROR == glGetError());
}

TEST_F(GLCopyTextureCHROMIUMTest, ProgramStatePreservation) {
  // unbind the one created in setup.
  glBindFramebuffer(GL_FRAMEBUFFER, 0);
  glBindTexture(GL_TEXTURE_2D, 0);

  GLManager gl2;
  GLManager::Options options;
  options.size = gfx::Size(16, 16);
  options.share_group_manager = &gl_;
  gl2.Initialize(options);
  gl_.MakeCurrent();

  static const char* v_shader_str =
      "attribute vec4 g_Position;\n"
      "void main()\n"
      "{\n"
      "   gl_Position = g_Position;\n"
      "}\n";
  static const char* f_shader_str =
      "precision mediump float;\n"
      "void main()\n"
      "{\n"
      "  gl_FragColor = vec4(0,1,0,1);\n"
      "}\n";

  GLuint program = GLTestHelper::LoadProgram(v_shader_str, f_shader_str);
  glUseProgram(program);
  GLuint position_loc = glGetAttribLocation(program, "g_Position");
  glFlush();

  // Delete program from other context.
  gl2.MakeCurrent();
  glDeleteProgram(program);
  EXPECT_TRUE(GL_NO_ERROR == glGetError());
  glFlush();

  // Program should still be usable on this context.
  gl_.MakeCurrent();

  GLTestHelper::SetupUnitQuad(position_loc);

  // test using program before
  uint8 expected[] = { 0, 255, 0, 255, };
  uint8 zero[] = { 0, 0, 0, 0, };
  glClear(GL_COLOR_BUFFER_BIT);
  EXPECT_TRUE(GLTestHelper::CheckPixels(0, 0, 1, 1, 0, zero));
  glDrawArrays(GL_TRIANGLES, 0, 6);
  EXPECT_TRUE(GLTestHelper::CheckPixels(0, 0, 1, 1, 0, expected));

  // Call copyTextureCHROMIUM
  uint8 pixels[1 * 4] = { 255u, 0u, 0u, 255u };
  glBindTexture(GL_TEXTURE_2D, textures_[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE,
               pixels);
  glCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1], 0, GL_RGBA,
                        GL_UNSIGNED_BYTE);

  // test using program after
  glClear(GL_COLOR_BUFFER_BIT);
  EXPECT_TRUE(GLTestHelper::CheckPixels(0, 0, 1, 1, 0, zero));
  glDrawArrays(GL_TRIANGLES, 0, 6);
  EXPECT_TRUE(GLTestHelper::CheckPixels(0, 0, 1, 1, 0, expected));

  EXPECT_TRUE(GL_NO_ERROR == glGetError());

  gl2.MakeCurrent();
  gl2.Destroy();
  gl_.MakeCurrent();
}

// Test that glCopyTextureCHROMIUM doesn't leak uninitialized textures.
TEST_F(GLCopyTextureCHROMIUMTest, UninitializedSource) {
  const GLsizei kWidth = 64, kHeight = 64;
  glBindTexture(GL_TEXTURE_2D, textures_[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kWidth, kHeight,
               0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);

  glCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1], 0, GL_RGBA,
                        GL_UNSIGNED_BYTE);
  EXPECT_TRUE(GL_NO_ERROR == glGetError());

  uint8 pixels[kHeight][kWidth][4] = {{{1}}};
  glReadPixels(0, 0, kWidth, kHeight, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
  for (int x = 0; x < kWidth; ++x) {
    for (int y = 0; y < kHeight; ++y) {
      EXPECT_EQ(0, pixels[y][x][0]);
      EXPECT_EQ(0, pixels[y][x][1]);
      EXPECT_EQ(0, pixels[y][x][2]);
      EXPECT_EQ(0, pixels[y][x][3]);
    }
  }

  EXPECT_TRUE(GL_NO_ERROR == glGetError());
}

}  // namespace gpu