Add R_8 GPU memory buffers format.

GpuMemoryBuffer::Format::R_8 should be used to represent textures with
only one channel, the associated image should have GL_R8/GL_R8_EXT
as internal format.

With this CL the only implementation of GpuMemoryBuffer that supports
R_8 is GLImageMemory, it expects a 4 bytes row alignment (4 is the
default value for GL_PACK_ALIGNMENT).

BUG=

Review URL: https://codereview.chromium.org/1051503003

Cr-Commit-Position: refs/heads/master@{#324281}

7 files changed, 35 insertions, 4 deletions

diff --git a/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_image.txt b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_image.txt
index 645a3f4..e0ba066 100644
--- a/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_image.txt
+++ b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_image.txt
@@ -15,6 +15,7 @@ Dependencies
     OpenGL ES 2.0 is required.
 
     EXT_texture_format_BGRA8888 affects the definition of this extension.
+    ARB_texture_rg affects the definition of this extension.
 
 Overview
 
@@ -45,7 +46,7 @@ New Procedures and Functions
     INVALID_VALUE is generated if <width> or <height> is nonpositive.
 
     INVALID_ENUM is generated if <internalformat> is not one of
-    RGB, RGBA or GL_BGRA_EXT.
+    R8, RGB, RGBA or BGRA_EXT.
 
     void DestroyImageCHROMIUM(GLuint image_id)
 
@@ -56,7 +57,12 @@ New Procedures and Functions
 Dependencies on EXT_texture_format_BGRA8888
 
     If EXT_texture_format_BGRA8888 is not supported:
-     * delete any reference to the GL_BGRA_EXT format.
+     * delete any reference to the BGRA_EXT format.
+
+Dependencies on ARB_texture_rg
+
+    If ARB_texture_rg is not supported:
+     * delete any reference to the R8 format.
 
 Errors
 
@@ -71,4 +77,5 @@ Revision History
     5/9/2013    Documented the extension
     4/30/2014   Moved usage flag to creation function.
     10/7/2014   Remove map/unmap API.
-    4/6/2015    Add GL_BGRA_EXT format.
+    4/6/2015    Add BGRA_EXT format.
+    2/7/2015    Add R8 format.
diff --git a/gpu/command_buffer/client/gles2_implementation.cc b/gpu/command_buffer/client/gles2_implementation.cc
index c93017c..1327826 100644
--- a/gpu/command_buffer/client/gles2_implementation.cc
+++ b/gpu/command_buffer/client/gles2_implementation.cc
@@ -4829,6 +4829,7 @@ namespace {
 
 bool ValidImageFormat(GLenum internalformat) {
   switch (internalformat) {
+    case GL_R8:
     case GL_RGB:
     case GL_RGBA:
     case GL_BGRA_EXT:
diff --git a/gpu/command_buffer/service/feature_info.cc b/gpu/command_buffer/service/feature_info.cc
index dcbdb8f..5003ea8 100644
--- a/gpu/command_buffer/service/feature_info.cc
+++ b/gpu/command_buffer/service/feature_info.cc
@@ -1070,7 +1070,9 @@ void FeatureInfo::InitializeFeatures() {
     validators_.texture_format.AddValue(GL_RED_EXT);
     validators_.texture_format.AddValue(GL_RG_EXT);
     validators_.texture_internal_format.AddValue(GL_RED_EXT);
+    validators_.texture_internal_format.AddValue(GL_R8_EXT);
     validators_.texture_internal_format.AddValue(GL_RG_EXT);
+    validators_.texture_internal_format.AddValue(GL_RG8_EXT);
     validators_.read_pixel_format.AddValue(GL_RED_EXT);
     validators_.read_pixel_format.AddValue(GL_RG_EXT);
     validators_.render_buffer_format.AddValue(GL_R8_EXT);
diff --git a/gpu/command_buffer/service/image_factory.cc b/gpu/command_buffer/service/image_factory.cc
index f09cfb8..74994ff 100644
--- a/gpu/command_buffer/service/image_factory.cc
+++ b/gpu/command_buffer/service/image_factory.cc
@@ -19,6 +19,8 @@ ImageFactory::~ImageFactory() {
 gfx::GpuMemoryBuffer::Format ImageFactory::ImageFormatToGpuMemoryBufferFormat(
     unsigned internalformat) {
   switch (internalformat) {
+    case GL_R8:
+      return gfx::GpuMemoryBuffer::R_8;
     case GL_RGB:
       return gfx::GpuMemoryBuffer::RGBX_8888;
     case GL_RGBA:
@@ -78,6 +80,8 @@ bool ImageFactory::IsGpuMemoryBufferFormatSupported(
       return capabilities.texture_format_dxt5;
     case gfx::GpuMemoryBuffer::ETC1:
       return capabilities.texture_format_etc1;
+    case gfx::GpuMemoryBuffer::R_8:
+      return capabilities.texture_rg;
     case gfx::GpuMemoryBuffer::RGBA_8888:
     case gfx::GpuMemoryBuffer::RGBX_8888:
     case gfx::GpuMemoryBuffer::YUV_420:
@@ -101,6 +105,7 @@ bool ImageFactory::IsImageSizeValidForGpuMemoryBufferFormat(
       // Compressed images must have a width and height that's evenly divisible
       // by the block size.
       return size.width() % 4 == 0 && size.height() % 4 == 0;
+    case gfx::GpuMemoryBuffer::R_8:
     case gfx::GpuMemoryBuffer::RGBA_8888:
     case gfx::GpuMemoryBuffer::BGRA_8888:
     case gfx::GpuMemoryBuffer::RGBX_8888:
diff --git a/gpu/command_buffer/service/in_process_command_buffer.cc b/gpu/command_buffer/service/in_process_command_buffer.cc
index 65986f8..71a6532 100644
--- a/gpu/command_buffer/service/in_process_command_buffer.cc
+++ b/gpu/command_buffer/service/in_process_command_buffer.cc
@@ -713,6 +713,8 @@ int32 InProcessCommandBuffer::CreateImage(ClientBuffer buffer,
 
   int32 new_id = next_image_id_.GetNext();
 
+  DCHECK(gpu::ImageFactory::IsGpuMemoryBufferFormatSupported(
+      gpu_memory_buffer->GetFormat(), capabilities_));
   DCHECK(gpu::ImageFactory::IsImageFormatCompatibleWithGpuMemoryBufferFormat(
       internalformat, gpu_memory_buffer->GetFormat()));
 
diff --git a/gpu/command_buffer/tests/gl_gpu_memory_buffer_unittest.cc b/gpu/command_buffer/tests/gl_gpu_memory_buffer_unittest.cc
index 9368da5..51b3640 100644
--- a/gpu/command_buffer/tests/gl_gpu_memory_buffer_unittest.cc
+++ b/gpu/command_buffer/tests/gl_gpu_memory_buffer_unittest.cc
@@ -80,6 +80,9 @@ SHADER(
 std::vector<uint8> GetTexturePixel(const gfx::GpuMemoryBuffer::Format format) {
   std::vector<uint8> pixel;
   switch (format) {
+    case gfx::GpuMemoryBuffer::R_8:
+      pixel.push_back(255u);
+      return pixel;
     case gfx::GpuMemoryBuffer::RGBA_8888:
       pixel.push_back(255u);
       pixel.push_back(0u);
@@ -111,6 +114,7 @@ std::vector<uint8> GetFramebufferPixel(
     const gfx::GpuMemoryBuffer::Format format) {
   std::vector<uint8> pixel;
   switch (format) {
+    case gfx::GpuMemoryBuffer::R_8:
     case gfx::GpuMemoryBuffer::RGBA_8888:
     case gfx::GpuMemoryBuffer::BGRA_8888:
       pixel.push_back(255u);
@@ -135,6 +139,8 @@ std::vector<uint8> GetFramebufferPixel(
 
 GLenum InternalFormat(gfx::GpuMemoryBuffer::Format format) {
   switch (format) {
+    case gfx::GpuMemoryBuffer::R_8:
+      return GL_R8;
     case gfx::GpuMemoryBuffer::RGBA_8888:
       return GL_RGBA;
     case gfx::GpuMemoryBuffer::BGRA_8888:
@@ -158,6 +164,9 @@ GLenum InternalFormat(gfx::GpuMemoryBuffer::Format format) {
 
 // An end to end test that tests the whole GpuMemoryBuffer lifecycle.
 TEST_P(GpuMemoryBufferTest, Lifecycle) {
+  ASSERT_TRUE((GetParam() != gfx::GpuMemoryBuffer::R_8) ||
+              gl_.GetCapabilities().texture_rg);
+
   GLuint texture_id = 0;
   glGenTextures(1, &texture_id);
   ASSERT_NE(0u, texture_id);
@@ -243,7 +252,8 @@ TEST_P(GpuMemoryBufferTest, Lifecycle) {
 
 INSTANTIATE_TEST_CASE_P(GpuMemoryBufferTests,
                         GpuMemoryBufferTest,
-                        ::testing::Values(gfx::GpuMemoryBuffer::RGBA_8888,
+                        ::testing::Values(gfx::GpuMemoryBuffer::R_8,
+                                          gfx::GpuMemoryBuffer::RGBA_8888,
                                           gfx::GpuMemoryBuffer::BGRA_8888));
 
 }  // namespace gles2
diff --git a/gpu/command_buffer/tests/gl_manager.cc b/gpu/command_buffer/tests/gl_manager.cc
index 3a3d7e9..2b6d06d 100644
--- a/gpu/command_buffer/tests/gl_manager.cc
+++ b/gpu/command_buffer/tests/gl_manager.cc
@@ -46,6 +46,7 @@ size_t NumberOfPlanesForGpuMemoryBufferFormat(
     case gfx::GpuMemoryBuffer::Format::DXT1:
     case gfx::GpuMemoryBuffer::Format::DXT5:
     case gfx::GpuMemoryBuffer::Format::ETC1:
+    case gfx::GpuMemoryBuffer::Format::R_8:
     case gfx::GpuMemoryBuffer::Format::RGBA_8888:
     case gfx::GpuMemoryBuffer::Format::RGBX_8888:
     case gfx::GpuMemoryBuffer::Format::BGRA_8888:
@@ -64,6 +65,7 @@ size_t SubsamplingFactor(gfx::GpuMemoryBuffer::Format format, int plane) {
     case gfx::GpuMemoryBuffer::DXT1:
     case gfx::GpuMemoryBuffer::DXT5:
     case gfx::GpuMemoryBuffer::ETC1:
+    case gfx::GpuMemoryBuffer::R_8:
     case gfx::GpuMemoryBuffer::RGBA_8888:
     case gfx::GpuMemoryBuffer::RGBX_8888:
     case gfx::GpuMemoryBuffer::BGRA_8888:
@@ -92,6 +94,8 @@ size_t StrideInBytes(size_t width,
       DCHECK_EQ(plane, 0);
       DCHECK_EQ(width % 2, 0U);
       return width / 2;
+    case gfx::GpuMemoryBuffer::R_8:
+      return (width + 3) & ~0x3;
     case gfx::GpuMemoryBuffer::RGBA_8888:
     case gfx::GpuMemoryBuffer::BGRA_8888:
       DCHECK_EQ(plane, 0);