Implement support for rendering to 32-bit float textures on ES3

ui/gl/gl_gl_api_implementation.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.
 
 #include "ui/gl/gl_gl_api_implementation.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/strings/string_util.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_state_restorer.h"
 #include "ui/gl/gl_surface.h"
 #include "ui/gl/gl_switches.h"
+#include "ui/gl/gl_version_info.h"
 
 namespace gfx {
 
 // The GL Api being used. This could be g_real_gl or gl_trace_gl
 static GLApi* g_gl;
 // A GL Api that calls directly into the driver.
 static RealGLApi* g_real_gl;
 // A GL Api that calls TRACE and then calls another GL api.
 static TraceGLApi* g_trace_gl;
+// GL version used when initializing dynamic bindings.
+static GLVersionInfo* g_version_info = NULL;
 
 namespace {
 
 static inline GLenum GetInternalFormat(GLenum internal_format) {
   if (gfx::GetGLImplementation() != gfx::kGLImplementationEGLGLES2) {
     if (internal_format == GL_BGRA_EXT || internal_format == GL_BGRA8_EXT)
       return GL_RGBA8;
   }
   return internal_format;
 }
 
 // TODO(epenner): Could the above function be merged into this and removed?
 static inline GLenum GetTexInternalFormat(GLenum internal_format,
                                           GLenum format,
                                           GLenum type) {
   GLenum gl_internal_format = GetInternalFormat(internal_format);
 
-  if (gfx::GetGLImplementation() == gfx::kGLImplementationEGLGLES2)
+  // g_version_info must be initialized when this function is bound.
+  DCHECK(gfx::g_version_info);
+  if (type == GL_FLOAT && gfx::g_version_info->is_angle &&
+      gfx::g_version_info->is_es2) {
+    // It's possible that the texture is using a sized internal format, and
+    // ANGLE exposing GLES2 API doesn't support those.

[piman, 2014/02/12 21:04:08]

nit: file a bug and reference here, so that we can remove this in the future.

+    switch (format) {
+      case GL_RGBA:
+        gl_internal_format = GL_RGBA;
+        break;
+      case GL_RGB:
+        gl_internal_format = GL_RGB;
+        break;
+      default:
+        break;
+    }
+  }
+
+  if (gfx::g_version_info->is_es)
     return gl_internal_format;
 
   if (type == GL_FLOAT) {
     switch (format) {
       case GL_RGBA:
         gl_internal_format = GL_RGBA32F_ARB;
         break;
       case GL_RGB:
         gl_internal_format = GL_RGB32F_ARB;
         break;
@@ skipping 147 matching lines @@
 void SetGLApi(GLApi* api) {
   g_current_gl_context_tls->Set(api);
 }
 
 void SetGLToRealGLApi() {
   SetGLApi(g_gl);
 }
 
 void InitializeDynamicGLBindingsGL(GLContext* context) {
   g_driver_gl.InitializeCustomDynamicBindings(context);
+  DCHECK(context && context->IsCurrent(NULL) && !g_version_info);
+  g_version_info = new GLVersionInfo(context->GetGLVersion().c_str(),
+      context->GetGLRenderer().c_str());
 }
 
 void InitializeDebugGLBindingsGL() {
   g_driver_gl.InitializeDebugBindings();
 }
 
 void InitializeNullDrawGLBindingsGL() {
   g_driver_gl.InitializeNullDrawBindings();
 }
 
 void ClearGLBindingsGL() {
   if (g_real_gl) {
     delete g_real_gl;
     g_real_gl = NULL;
   }
   if (g_trace_gl) {
     delete g_trace_gl;
     g_trace_gl = NULL;
   }
   g_gl = NULL;
   g_driver_gl.ClearBindings();
   if (g_current_gl_context_tls) {
     delete g_current_gl_context_tls;
     g_current_gl_context_tls = NULL;
   }
+  if (g_version_info) {
+    delete g_version_info;
+    g_version_info = NULL;
+  }
 }
 
 GLApi::GLApi() {
 }
 
 GLApi::~GLApi() {
   if (GetCurrentGLApi() == this)
     SetGLApi(NULL);
 }
 
@@ skipping 104 matching lines @@
 const GLubyte* VirtualGLApi::glGetStringFn(GLenum name) {
   switch (name) {
     case GL_EXTENSIONS:
       return reinterpret_cast<const GLubyte*>(extensions_.c_str());
     default:
       return driver_->fn.glGetStringFn(name);
   }
 }
 
 }  // namespace gfx