Add glCompressedCopySubTextureCHROMIUM

gpu/command_buffer/tests/gl_compressed_copy_texture_CHROMIUM_unittest.cc

 // 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.
 
 #ifndef GL_GLEXT_PROTOTYPES
 #define GL_GLEXT_PROTOTYPES
 #endif
 
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 #include <GLES2/gl2extchromium.h>
 
 #include "base/memory/scoped_vector.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"
 
 #define SHADER(src) #src
 
 namespace gpu {
 
 namespace {
 
+enum CopyType { TexImage, TexSubImage };
+const CopyType kCopyTypes[] = {
+    TexImage,
+    TexSubImage,
+};
+
 const uint8 kCompressedImageColor[4] = { 255u, 0u, 0u, 255u };
 
 // Single compressed ATC block of source pixels all set to:
 // kCompressedImageColor.
 const uint8 kCompressedImageATC[8] = {
     0x0, 0x7c, 0x0, 0xf8, 0x55, 0x55, 0x55, 0x55 };
 
 // Single compressed ATCIA block of source pixels all set to:
 // kCompressedImageColor.
 const uint8 kCompressedImageATCIA[16] = {
     0xff, 0xff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x7c, 0x0, 0xf8, 0x55, 0x55, 0x55, 0x55 };
 
 // Single compressed DXT1 block of source pixels all set to:
 // kCompressedImageColor.
 const uint8 kCompressedImageDXT1[8] = {
     0x00, 0xf8, 0x00, 0xf8, 0xaa, 0xaa, 0xaa, 0xaa };
 
+// Four compressed DXT1 blocks solidly colored in red, green, blue and black:
+// [R][G]
+// [B][b]
+const uint8 kCompressedImageDXT1RGB[32] = {
+    0x0, 0xf8, 0x0, 0xf8, 0xaa, 0xaa, 0xaa, 0xaa,
+    0xe0, 0x7, 0xe0, 0x7, 0xaa, 0xaa, 0xaa, 0xaa,
+    0x1f, 0x0, 0x1f, 0x0, 0xaa, 0xaa, 0xaa, 0xaa,
+    0x0, 0x0, 0x0, 0x0, 0xaa, 0xaa, 0xaa, 0xaa };
+
 // Single compressed DXT5 block of source pixels all set to:
 // kCompressedImageColor.
 const uint8 kCompressedImageDXT5[16] = {
     0xff, 0xff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0xf8, 0x0, 0xf8, 0xaa, 0xaa, 0xaa, 0xaa };
 
 // Single compressed DXT1 block of source pixels all set to:
 // kCompressedImageColor.
 const uint8 kCompressedImageETC1[8] = {
     0x0, 0x0, 0xf8, 0x2, 0xff, 0xff, 0x0, 0x0 };
 
+// Single block of zeroes, used for texture pre-allocation.
+const uint8 kInvalidCompressedImage[8] = {
+    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 };
+
+// Four blocks of zeroes, used for texture pre-allocation.
+const uint8 kInvalidCompressedImageLarge[32] = {
+    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 };
+
 void glEnableDisable(GLint param, GLboolean value) {
   if (value)
     glEnable(param);
   else
     glDisable(param);
 }
 
 }  // unnamed namespace
 
 // A collection of tests that exercise the GL_CHROMIUM_copy_texture extension.
 class GLCompressedCopyTextureCHROMIUMTest
-    : public testing::Test {
+    : public testing::Test,
+      public ::testing::WithParamInterface<CopyType> {
  protected:
   void SetUp() override {
     gl_.Initialize(GLManager::Options());
 
     glGenTextures(2, textures_);
   }
 
   void TearDown() override {
     glDeleteTextures(2, textures_);
     gl_.Destroy();
@@ skipping 17 matching lines @@
         }
     );
     return GLTestHelper::LoadProgram(v_shader_src, f_shader_src);
   }
 
   GLManager gl_;
   GLuint textures_[2];
   GLuint framebuffer_id_;
 };
 
+INSTANTIATE_TEST_CASE_P(CopyType,
+                        GLCompressedCopyTextureCHROMIUMTest,
+                        ::testing::ValuesIn(kCopyTypes));
+
 // Test to ensure that the basic functionality of the extension works.
-TEST_F(GLCompressedCopyTextureCHROMIUMTest, Basic) {
+TEST_P(GLCompressedCopyTextureCHROMIUMTest, Basic) {
   if (!GLTestHelper::HasExtension("GL_EXT_texture_compression_dxt1")) {
     LOG(INFO) <<
         "GL_EXT_texture_compression_dxt1 not supported. Skipping test...";
     return;
   }
 
+  CopyType copy_type = GetParam();
+
   glBindTexture(GL_TEXTURE_2D, textures_[0]);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
                          4, 4, 0,
                          sizeof(kCompressedImageDXT1), kCompressedImageDXT1);
   EXPECT_TRUE(glGetError() == GL_NO_ERROR);
 
   glBindTexture(GL_TEXTURE_2D, textures_[1]);
   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);
-  glCompressedCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1]);
+  if (copy_type == TexImage) {
+    glCompressedCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1]);
+  } else {
+    glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                           4, 4, 0,
+                           sizeof(kInvalidCompressedImage),
+                           kInvalidCompressedImage);
+
+    glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                       textures_[1], 0, 0, 0, 0, 4, 4);
+  }
   EXPECT_TRUE(glGetError() == GL_NO_ERROR);
 
   // Load shader program.
   GLuint program = LoadProgram();
   ASSERT_NE(program, 0u);
   GLint position_loc = glGetAttribLocation(program, "a_position");
   GLint texture_loc = glGetUniformLocation(program, "u_texture");
   ASSERT_NE(position_loc, -1);
   ASSERT_NE(texture_loc, -1);
   glUseProgram(program);
 
   // Load geometry.
   GLuint vbo = GLTestHelper::SetupUnitQuad(position_loc);
   ASSERT_NE(vbo, 0u);
 
   // Load texture.
   glActiveTexture(GL_TEXTURE0);
   glBindTexture(GL_TEXTURE_2D, textures_[1]);
   glUniform1i(texture_loc, 0);
 
   // Draw.
   glDrawArrays(GL_TRIANGLES, 0, 6);
   glFlush();
 
   GLTestHelper::CheckPixels(0, 0, 4, 4, 0, kCompressedImageColor);
   EXPECT_TRUE(GL_NO_ERROR == glGetError());
 }
 
-TEST_F(GLCompressedCopyTextureCHROMIUMTest, InternalFormat) {
+TEST_P(GLCompressedCopyTextureCHROMIUMTest, InternalFormat) {
+  CopyType copy_type = GetParam();
+
   struct Image {
     const GLint format;
     const uint8* data;
     const GLsizei data_size;
 
     Image(const GLint format, const uint8* data, const GLsizei data_size) :
       format(format), data(data), data_size(data_size) {}
   };
   ScopedVector<Image> supported_formats;
 
@@ skipping 36 matching lines @@
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glCompressedTexImage2D(GL_TEXTURE_2D, 0, image->format,
                            4, 4, 0, image->data_size, image->data);
     EXPECT_TRUE(GL_NO_ERROR == glGetError());
 
     glBindTexture(GL_TEXTURE_2D, textures_[1]);
     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);
-    glCompressedCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1]);
+    if (copy_type == TexImage) {
+      glCompressedCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                      textures_[1]);
+    } else {
+      glCompressedTexImage2D(GL_TEXTURE_2D, 0, image->format, 4, 4, 0,
+                             sizeof(kInvalidCompressedImage),
+                             kInvalidCompressedImage);
+
+      glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                         textures_[1], 0, 0, 0, 0, 4, 4);
+    }
     EXPECT_TRUE(GL_NO_ERROR == glGetError());
   }
 }
 
-TEST_F(GLCompressedCopyTextureCHROMIUMTest, InternalFormatNotSupported) {
+TEST_P(GLCompressedCopyTextureCHROMIUMTest, InternalFormatNotSupported) {
   if (!GLTestHelper::HasExtension("GL_EXT_texture_compression_dxt1")) {
     LOG(INFO) <<
         "GL_EXT_texture_compression_dxt1 not supported. Skipping test...";
     return;
   }
 
+  CopyType copy_type = GetParam();
+
   const uint8 kUncompressedPixels[1 * 4] = { 255u, 0u, 0u, 255u };
 
   glBindTexture(GL_TEXTURE_2D, textures_[0]);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE,
                kUncompressedPixels);
   EXPECT_TRUE(glGetError() == GL_NO_ERROR);
 
   glBindTexture(GL_TEXTURE_2D, textures_[1]);
   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);
 
   // Check that the GL_RGBA format reports an error.
-  glCompressedCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1]);
+  if (copy_type == TexImage) {
+    glCompressedCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1]);
+  } else {
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE,
+                 kUncompressedPixels);
+
+    glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                       textures_[1], 0, 0, 0, 0, 1, 1);
+  }
   EXPECT_TRUE(GL_INVALID_OPERATION == glGetError());
 }
 
 // Validate that some basic GL state is not touched upon execution of
 // the extension.
-TEST_F(GLCompressedCopyTextureCHROMIUMTest, BasicStatePreservation) {
+TEST_P(GLCompressedCopyTextureCHROMIUMTest, BasicStatePreservation) {
   if (!GLTestHelper::HasExtension("GL_EXT_texture_compression_dxt1")) {
     LOG(INFO) <<
         "GL_EXT_texture_compression_dxt1 not supported. Skipping test...";
     return;
   }
 
+  CopyType copy_type = GetParam();
+
   glBindTexture(GL_TEXTURE_2D, textures_[0]);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
                          4, 4, 0,
                          sizeof(kCompressedImageDXT1), kCompressedImageDXT1);
   EXPECT_TRUE(glGetError() == GL_NO_ERROR);
 
   glBindTexture(GL_TEXTURE_2D, textures_[1]);
   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);
 
+  if (copy_type == TexSubImage) {
+    glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                           4, 4, 0,
+                           sizeof(kInvalidCompressedImage),
+                           kInvalidCompressedImage);
+  }
+
   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);
 
-    glCompressedCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1]);
+    if (copy_type == TexImage) {
+      glCompressedCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                      textures_[1]);
+    } else {
+      glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                         textures_[1], 0, 0, 0, 0, 4, 4);
+    }
     EXPECT_TRUE(glGetError() == GL_NO_ERROR);
 
     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(GLCompressedCopyTextureCHROMIUMTest, TextureStatePreserved) {
+TEST_P(GLCompressedCopyTextureCHROMIUMTest, TextureStatePreserved) {
   if (!GLTestHelper::HasExtension("GL_EXT_texture_compression_dxt1")) {
     LOG(INFO) <<
         "GL_EXT_texture_compression_dxt1 not supported. Skipping test...";
     return;
   }
 
+  CopyType copy_type = GetParam();
+
   glBindTexture(GL_TEXTURE_2D, textures_[0]);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
                          4, 4, 0,
                          sizeof(kCompressedImageDXT1), kCompressedImageDXT1);
   EXPECT_TRUE(glGetError() == GL_NO_ERROR);
 
   glBindTexture(GL_TEXTURE_2D, textures_[1]);
   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);
 
+  if (copy_type == TexSubImage) {
+    glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                           4, 4, 0,
+                           sizeof(kInvalidCompressedImage),
+                           kInvalidCompressedImage);
+  }
+
   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]);
 
-  glCompressedCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1]);
+  if (copy_type == TexImage) {
+    glCompressedCopyTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1]);
+  } else {
+    glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                       textures_[1], 0, 0, 0, 0, 4, 4);
+  }
   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());
 }
 
+TEST_F(GLCompressedCopyTextureCHROMIUMTest, CopySubTextureDimension) {
+  if (!GLTestHelper::HasExtension("GL_EXT_texture_compression_dxt1")) {
+    LOG(INFO) <<
+        "GL_EXT_texture_compression_dxt1 not supported. Skipping test...";
+    return;
+  }
+
+  glBindTexture(GL_TEXTURE_2D, textures_[0]);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                         8, 8, 0,
+                         sizeof(kCompressedImageDXT1RGB),
+                         kCompressedImageDXT1RGB);
+  EXPECT_TRUE(glGetError() == GL_NO_ERROR);
+
+  glBindTexture(GL_TEXTURE_2D, textures_[1]);
+  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);
+  glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                         8, 8, 0,
+                         sizeof(kInvalidCompressedImageLarge),
+                         kInvalidCompressedImageLarge);
+
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                     textures_[1], 4, 4, 0, 0, 4, 4);
+  EXPECT_TRUE(GL_NO_ERROR == glGetError());
+
+  // Reset the destination texture as it might have been converted to RGBA.
+  glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                         8, 8, 0,
+                         sizeof(kInvalidCompressedImageLarge),
+                         kInvalidCompressedImageLarge);
+
+  // xoffset < 0
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1],
+                                     -4, 4, 0, 0, 4, 4);
+  EXPECT_TRUE(glGetError() == GL_INVALID_VALUE);
+
+  // x < 0
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1],
+                                     4, 4, -4, 0, 4, 4);
+  EXPECT_TRUE(glGetError() == GL_INVALID_VALUE);
+
+  // xoffset + width > dest_width
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1],
+                                     8, 8, 0, 0, 4, 4);
+  EXPECT_TRUE(glGetError() == GL_INVALID_VALUE);
+
+  // x + width > source_width
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1],
+                                     0, 0, 8, 8, 4, 4);
+  EXPECT_TRUE(glGetError() == GL_INVALID_VALUE);
+
+  // xoffset not within block-boundary
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1],
+                                     3, 0, 0, 0, 4, 4);
+  EXPECT_TRUE(glGetError() == GL_INVALID_OPERATION);
+
+  // x not within block-boundary
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0], textures_[1],
+                                     0, 0, 3, 0, 4, 4);
+  EXPECT_TRUE(glGetError() == GL_INVALID_OPERATION);
+}
+
+TEST_F(GLCompressedCopyTextureCHROMIUMTest, CopySubTextureOffset) {
+  if (!GLTestHelper::HasExtension("GL_EXT_texture_compression_dxt1")) {
+    LOG(INFO) <<
+        "GL_EXT_texture_compression_dxt1 not supported. Skipping test...";
+    return;
+  }
+
+  glBindTexture(GL_TEXTURE_2D, textures_[0]);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                         8, 8, 0,
+                         sizeof(kCompressedImageDXT1RGB),
+                         kCompressedImageDXT1RGB);
+  EXPECT_TRUE(glGetError() == GL_NO_ERROR);
+
+  glBindTexture(GL_TEXTURE_2D, textures_[1]);
+  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);
+  glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                         8, 8, 0,
+                         sizeof(kInvalidCompressedImageLarge),
+                         kInvalidCompressedImageLarge);
+
+  // Load shader program.
+  GLuint program = LoadProgram();
+  ASSERT_NE(program, 0u);
+  GLint position_loc = glGetAttribLocation(program, "a_position");
+  GLint texture_loc = glGetUniformLocation(program, "u_texture");
+  ASSERT_NE(position_loc, -1);
+  ASSERT_NE(texture_loc, -1);
+  glUseProgram(program);
+
+  // Load geometry.
+  GLuint vbo = GLTestHelper::SetupUnitQuad(position_loc);
+  ASSERT_NE(vbo, 0u);
+
+  // Load texture.
+  glActiveTexture(GL_TEXTURE0);
+  glBindTexture(GL_TEXTURE_2D, textures_[1]);
+  glUniform1i(texture_loc, 0);
+
+  const uint8 kBlack[1 * 4] = {0u, 0u, 0u, 255u};
+  const uint8 kRed[1 * 4] = {255u, 0u, 0u, 255u};
+  const uint8 kGreen[1 * 4] = {0u, 255u, 0u, 255u};
+  const uint8 kBlue[1 * 4] = {0u, 0u, 255u, 255u};
+
+  // Copy each block one by one in a clockwise fashion. Note that we reset the
+  // destination texture after each copy operation. That's because on some
+  // platforms we might fallback into replacing the compressed destination
+  // texture with an uncompressed one.
+
+  // Move blue block up.
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                     textures_[1], 0, 0, 0, 4, 4, 4);
+  EXPECT_TRUE(glGetError() == GL_NO_ERROR);
+
+  glDrawArrays(GL_TRIANGLES, 0, 6);
+  glFlush();
+  GLTestHelper::CheckPixels(0, 0, 2, 2, 0, kBlue);
+
+  glBindTexture(GL_TEXTURE_2D, textures_[1]);
+  glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                         8, 8, 0,
+                         sizeof(kInvalidCompressedImageLarge),
+                         kInvalidCompressedImageLarge);
+
+  // Move red block right.
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                     textures_[1], 4, 0, 0, 0, 4, 4);
+  EXPECT_TRUE(glGetError() == GL_NO_ERROR);
+
+  glDrawArrays(GL_TRIANGLES, 0, 6);
+  glFlush();
+  GLTestHelper::CheckPixels(2, 0, 2, 2, 0, kRed);
+
+  glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                         8, 8, 0,
+                         sizeof(kInvalidCompressedImageLarge),
+                         kInvalidCompressedImageLarge);
+
+  // Move green block down.
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                     textures_[1], 4, 4, 4, 0, 4, 4);
+  EXPECT_TRUE(glGetError() == GL_NO_ERROR);
+
+  glDrawArrays(GL_TRIANGLES, 0, 6);
+  glFlush();
+  GLTestHelper::CheckPixels(2, 2, 2, 2, 0, kGreen);
+
+  glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                         8, 8, 0,
+                         sizeof(kInvalidCompressedImageLarge),
+                         kInvalidCompressedImageLarge);
+
+  // Move black block left.
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                     textures_[1], 0, 4, 4, 4, 4, 4);
+  EXPECT_TRUE(glGetError() == GL_NO_ERROR);
+
+  glDrawArrays(GL_TRIANGLES, 0, 6);
+  glFlush();
+  GLTestHelper::CheckPixels(0, 2, 2, 2, 0, kBlack);
+
+  EXPECT_TRUE(GL_NO_ERROR == glGetError());
+}
+
+TEST_F(GLCompressedCopyTextureCHROMIUMTest, CopySubTexturePreservation) {
+  if (!GLTestHelper::HasExtension("GL_EXT_texture_compression_dxt1")) {
+    LOG(INFO) <<
+        "GL_EXT_texture_compression_dxt1 not supported. Skipping test...";
+    return;
+  }
+
+  glBindTexture(GL_TEXTURE_2D, textures_[0]);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                         4, 4, 0,
+                         sizeof(kCompressedImageDXT1),
+                         kCompressedImageDXT1);
+  EXPECT_TRUE(glGetError() == GL_NO_ERROR);
+
+  glBindTexture(GL_TEXTURE_2D, textures_[1]);
+  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);
+  glCompressedTexImage2D(GL_TEXTURE_2D, 0, GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                         8, 8, 0,
+                         sizeof(kCompressedImageDXT1RGB),
+                         kCompressedImageDXT1RGB);
+
+  // Copy entire first texture into the second, replacing the green block:
+  // [R][R]
+  // [B][b]
+  glCompressedCopySubTextureCHROMIUM(GL_TEXTURE_2D, textures_[0],
+                                     textures_[1], 4, 0, 0, 0, 4, 4);
+  EXPECT_TRUE(glGetError() == GL_NO_ERROR);
+
+  // Load shader program.
+  GLuint program = LoadProgram();
+  ASSERT_NE(program, 0u);
+  GLint position_loc = glGetAttribLocation(program, "a_position");
+  GLint texture_loc = glGetUniformLocation(program, "u_texture");
+  ASSERT_NE(position_loc, -1);
+  ASSERT_NE(texture_loc, -1);
+  glUseProgram(program);
+
+  // Load geometry.
+  GLuint vbo = GLTestHelper::SetupUnitQuad(position_loc);
+  ASSERT_NE(vbo, 0u);
+
+  // Load texture.
+  glActiveTexture(GL_TEXTURE0);
+  glBindTexture(GL_TEXTURE_2D, textures_[1]);
+  glUniform1i(texture_loc, 0);
+
+  // Draw.
+  glDrawArrays(GL_TRIANGLES, 0, 6);
+  glFlush();
+
+  const uint8 kBlack[1 * 4] = {0u, 0u, 0u, 255u};
+  const uint8 kRed[1 * 4] = {255u, 0u, 0u, 255u};
+  const uint8 kBlue[1 * 4] = {0u, 0u, 255u, 255u};
+
+  // Note that while destination texture is 8 x 8 pixels the viewport is only
+  // 4 x 4.
+  GLTestHelper::CheckPixels(0, 0, 4, 2, 0, kRed);
+  GLTestHelper::CheckPixels(0, 2, 2, 2, 0, kBlue);
+  GLTestHelper::CheckPixels(2, 2, 2, 2, 0, kBlack);
+  EXPECT_TRUE(GL_NO_ERROR == glGetError());
+}
+
 }  // namespace gpu