WebGL: GL_RGB emulation for IOSurface backed textures. [For reference only]

ui/gl/gl_image_io_surface.mm

 // Copyright 2013 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 "ui/gl/gl_image_io_surface.h"
 
 #include <map>
 
 #include "base/lazy_instance.h"
 #include "base/mac/foundation_util.h"
@@ skipping 51 matching lines @@
         texture2DRect(a_y_texture, v_texCoord).r,
         texture2DRect(a_uv_texture, v_texCoord * 0.5).rg);
     gl_FragColor = vec4(yuv_matrix * (yuv + yuv_adj), 1.0);
   }
 );
 // clang-format on
 
 bool ValidInternalFormat(unsigned internalformat) {
   switch (internalformat) {
     case GL_RED:
+    case GL_BGR_EXT:
     case GL_BGRA_EXT:
     case GL_RGB:
     case GL_RGB_YCBCR_420V_CHROMIUM:
     case GL_RGB_YCBCR_422_CHROMIUM:
     case GL_RGBA:
       return true;
     default:
       return false;
   }
 }
 
 bool ValidFormat(BufferFormat format) {
   switch (format) {
     case BufferFormat::R_8:
     case BufferFormat::BGRA_8888:
     case BufferFormat::RGBA_8888:
     case BufferFormat::UYVY_422:
     case BufferFormat::YUV_420_BIPLANAR:
+    case BufferFormat::BGRX_8888:
       return true;
     case BufferFormat::ATC:
     case BufferFormat::ATCIA:
     case BufferFormat::DXT1:
     case BufferFormat::DXT5:
     case BufferFormat::ETC1:
     case BufferFormat::RGBA_4444:
     case BufferFormat::RGBX_8888:
-    case BufferFormat::BGRX_8888:
     case BufferFormat::YUV_420:
       return false;
   }
 
   NOTREACHED();
   return false;
 }
 
 GLenum TextureFormat(BufferFormat format) {
   switch (format) {
     case BufferFormat::R_8:
       return GL_RED;
     case BufferFormat::BGRA_8888:
     case BufferFormat::RGBA_8888:
+    case BufferFormat::BGRX_8888:
       return GL_RGBA;
     case BufferFormat::UYVY_422:
       return GL_RGB;
     case BufferFormat::YUV_420_BIPLANAR:
       return GL_RGB_YCBCR_420V_CHROMIUM;
     case BufferFormat::ATC:
     case BufferFormat::ATCIA:
     case BufferFormat::DXT1:
     case BufferFormat::DXT5:
     case BufferFormat::ETC1:
     case BufferFormat::RGBA_4444:
     case BufferFormat::RGBX_8888:
-    case BufferFormat::BGRX_8888:
     case BufferFormat::YUV_420:
       NOTREACHED();
       return 0;
   }
 
   NOTREACHED();
   return 0;
 }
 
 GLenum DataFormat(BufferFormat format) {
   switch (format) {
     case BufferFormat::R_8:
       return GL_RED;
     case BufferFormat::BGRA_8888:
     case BufferFormat::RGBA_8888:
+    case BufferFormat::BGRX_8888:
       return GL_BGRA;
     case BufferFormat::UYVY_422:
       return GL_YCBCR_422_APPLE;
     case BufferFormat::ATC:
     case BufferFormat::ATCIA:
     case BufferFormat::DXT1:
     case BufferFormat::DXT5:
     case BufferFormat::ETC1:
     case BufferFormat::RGBA_4444:
     case BufferFormat::RGBX_8888:
-    case BufferFormat::BGRX_8888:
     case BufferFormat::YUV_420:
     case BufferFormat::YUV_420_BIPLANAR:
       NOTREACHED();
       return 0;
   }
 
   NOTREACHED();
   return 0;
 }
 
 GLenum DataType(BufferFormat format) {
   switch (format) {
     case BufferFormat::R_8:
       return GL_UNSIGNED_BYTE;
     case BufferFormat::BGRA_8888:
     case BufferFormat::RGBA_8888:
+    case BufferFormat::BGRX_8888:
       return GL_UNSIGNED_INT_8_8_8_8_REV;
     case BufferFormat::UYVY_422:
       return GL_UNSIGNED_SHORT_8_8_APPLE;
       break;
     case BufferFormat::ATC:
     case BufferFormat::ATCIA:
     case BufferFormat::DXT1:
     case BufferFormat::DXT5:
     case BufferFormat::ETC1:
     case BufferFormat::RGBA_4444:
     case BufferFormat::RGBX_8888:
-    case BufferFormat::BGRX_8888:
     case BufferFormat::YUV_420:
     case BufferFormat::YUV_420_BIPLANAR:
       NOTREACHED();
       return 0;
   }
 
   NOTREACHED();
   return 0;
 }
 
 }  // namespace
 
 GLImageIOSurface::GLImageIOSurface(const gfx::Size& size,
                                    unsigned internalformat)
     : size_(size),
       internalformat_(internalformat),
-      format_(BufferFormat::RGBA_8888) {}
+      desired_internalformat_(internalformat),
+      format_(BufferFormat::RGBA_8888) {
+  if (internalformat == GL_BGR_EXT)
+    internalformat_ = GL_BGRA_EXT;
+}
 
 GLImageIOSurface::~GLImageIOSurface() {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!io_surface_);
 }
 
 bool GLImageIOSurface::Initialize(IOSurfaceRef io_surface,
                                   gfx::GenericSharedMemoryId io_surface_id,
                                   BufferFormat format) {
   DCHECK(thread_checker_.CalledOnValidThread());
@@ skipping 191 matching lines @@
   dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                   base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                   static_cast<uint64_t>(size_bytes));
 
   auto guid =
       GetGenericSharedMemoryGUIDForTracing(process_tracing_id, io_surface_id_);
   pmd->CreateSharedGlobalAllocatorDump(guid);
   pmd->AddOwnershipEdge(dump->guid(), guid);
 }
 
+bool GLImageIOSurface::EmulatingRGB() const {
+  return desired_internalformat_ == GL_BGR_EXT;
+}
+
 base::ScopedCFTypeRef<IOSurfaceRef> GLImageIOSurface::io_surface() {
   return io_surface_;
 }
 
 // static
 void GLImageIOSurface::SetLayerForWidget(gfx::AcceleratedWidget widget,
                                          CALayer* layer) {
   if (layer)
     g_widget_to_layer_map.Pointer()->insert(std::make_pair(widget, layer));
   else
     g_widget_to_layer_map.Pointer()->erase(widget);
 }
 
 // static
 unsigned GLImageIOSurface::GetInternalFormatForTesting(
     gfx::BufferFormat format) {
   DCHECK(ValidFormat(format));
   return TextureFormat(format);
 }
 }  // namespace gl