gpu: fix CopyTextureCHROMIUM for immutable texture.

We cannot use glCopyTexImage2D on the texture which is allocated by glTexStorage2D [1]
[1] https://www.opengl.org/registry/specs/ARB/texture_storage.txt
The fast path uses glCopyTexSubImage2D instead of glCopyTexImage2D.

In addition, optimize CopyTextureCHROMIUM for GL_TEXTURE_RECTANGLE_ARB,
which is often used by the compositor, so make CopyTextureCHROMIUM use
the fast path.

Review URL: https://codereview.chromium.org/744713002

Cr-Commit-Position: refs/heads/master@{#305268}

2 files changed, 42 insertions, 13 deletions

diff --git a/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc b/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
index ffb9370..49bba9b 100644
--- a/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
+++ b/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
@@ -218,7 +218,6 @@ void DoCopyTexImage2D(const gpu::gles2::GLES2Decoder* decoder,
                       GLuint source_id,
                       GLuint dest_id,
                       GLint dest_level,
-                      GLenum dest_internal_format,
                       GLsizei width,
                       GLsizei height,
                       GLuint framebuffer) {
@@ -231,14 +230,8 @@ void DoCopyTexImage2D(const gpu::gles2::GLES2Decoder* decoder,
     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);
-    glCopyTexImage2D(GL_TEXTURE_2D,
-                     dest_level,
-                     dest_internal_format,
-                     0 /* x */,
-                     0 /* y */,
-                     width,
-                     height,
-                     0 /* border */);
+    glCopyTexSubImage2D(GL_TEXTURE_2D, dest_level, 0 /* xoffset */,
+                        0 /* yoffset */, 0 /* x */, 0 /* y */, width, height);
   }
 
   decoder->RestoreTextureState(source_id);
@@ -332,16 +325,15 @@ void CopyTextureCHROMIUMResourceManager::DoCopyTexture(
   bool source_format_contain_superset_of_dest_format =
       source_internal_format == dest_internal_format ||
       (source_internal_format == GL_RGBA && dest_internal_format == GL_RGB);
-  // GL_TEXTURE_RECTANGLE_ARB on FBO is supported by OpenGL, not GLES2,
-  // so restrict this to GL_TEXTURE_2D.
-  if (source_target == GL_TEXTURE_2D && !flip_y && !premultiply_alpha_change &&
+  bool source_target_allowed = source_target == GL_TEXTURE_2D ||
+                               source_target == GL_TEXTURE_RECTANGLE_ARB;
+  if (source_target_allowed && !flip_y && !premultiply_alpha_change &&
       source_format_contain_superset_of_dest_format) {
     DoCopyTexImage2D(decoder,
                      source_target,
                      source_id,
                      dest_id,
                      dest_level,
-                     dest_internal_format,
                      width,
                      height,
                      framebuffer_);
diff --git a/gpu/command_buffer/tests/gl_copy_texture_CHROMIUM_unittest.cc b/gpu/command_buffer/tests/gl_copy_texture_CHROMIUM_unittest.cc
index 2c44e1a..a8cbb66 100644
--- a/gpu/command_buffer/tests/gl_copy_texture_CHROMIUM_unittest.cc
+++ b/gpu/command_buffer/tests/gl_copy_texture_CHROMIUM_unittest.cc
@@ -76,6 +76,43 @@ TEST_F(GLCopyTextureCHROMIUMTest, Basic) {
   EXPECT_TRUE(GL_NO_ERROR == glGetError());
 }
 
+TEST_F(GLCopyTextureCHROMIUMTest, ImmutableTexture) {
+  if (!GLTestHelper::HasExtension("GL_EXT_texture_storage")) {
+    LOG(INFO) << "GL_EXT_texture_storage not supported. Skipping test...";
+    return;
+  }
+
+  uint8 pixels[1 * 4] = {255u, 0u, 0u, 255u};
+
+  glBindTexture(GL_TEXTURE_2D, textures_[0]);
+  glTexStorage2DEXT(GL_TEXTURE_2D, 1, GL_RGBA8_OES, 1, 1);
+  glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE,
+                  pixels);
+
+  glBindTexture(GL_TEXTURE_2D, textures_[1]);
+  glTexStorage2DEXT(GL_TEXTURE_2D, 1, GL_RGBA8_OES, 1, 1);
+  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+                         textures_[1], 0);
+  EXPECT_TRUE(glGetError() == GL_NO_ERROR);
+
+  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_F(GLCopyTextureCHROMIUMTest, InternalFormat) {
   GLint src_formats[] = {GL_ALPHA,     GL_RGB,             GL_RGBA,
                          GL_LUMINANCE, GL_LUMINANCE_ALPHA, GL_BGRA_EXT};