Enable texture readback support for Android

content/common/gpu/client/gl_helper.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 "content/common/gpu/client/gl_helper.h"
 
 #include <queue>
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
@@ skipping 215 matching lines @@
 }
 
 void SignalWaitableEvent(base::WaitableEvent* event) {
   event->Signal();
 }
 
 }  // namespace
 
 namespace content {
 
-// Implements GLHelper::CopyTextureTo and encapsulates the data needed for it.
+// Implements GLHelper::CropScaleReadbackAndCleanTexture and encapsulates the
+// data needed for it.
 class GLHelper::CopyTextureToImpl {
  public:
   CopyTextureToImpl(WebGraphicsContext3D* context,
                     WebGraphicsContext3D* context_for_thread,
                     GLHelper* helper)
       : context_(context),
         context_for_thread_(context_for_thread),
         helper_(helper),
         flush_(context),
         program_(context, context->createProgram()),
         vertex_attributes_buffer_(context_, context_->createBuffer()) {
     InitBuffer();
     InitProgram();
   }
   ~CopyTextureToImpl() {
     CancelRequests();
     DeleteContextForThread();
   }
 
   void InitBuffer();
   void InitProgram();
 
-  void CopyTextureTo(WebGLId src_texture,
-                     const gfx::Size& src_size,
-                     const gfx::Rect& src_subrect,
-                     const gfx::Size& dst_size,
-                     unsigned char* out,
-                     const base::Callback<void(bool)>& callback);
+  void CropScaleReadbackAndCleanTexture(
+      WebGLId src_texture,
+      const gfx::Size& src_size,
+      const gfx::Rect& src_subrect,
+      const gfx::Size& dst_size,
+      unsigned char* out,
+      const base::Callback<void(bool)>& callback);
 
-  WebKit::WebGLId CopyTexture(WebGLId src_texture, const gfx::Size& size);
+  void ReadbackTextureSync(WebGLId texture,
+                           const gfx::Size& size,
+                           unsigned char* out);
+
+  WebKit::WebGLId CopyAndScaleTexture(WebGLId texture,
+                                      const gfx::Size& src_size,
+                                      const gfx::Size& dst_size);
 
  private:
-  // A single request to CopyTextureTo.
+  // A single request to CropScaleReadbackAndCleanTexture.
   // Thread-safety notes: the main thread creates instances of this class. The
   // main thread can cancel the request, before it's handled by the helper
   // thread, by resetting the texture and pixels fields. Alternatively, the
   // thread marks that it handles the request by resetting the pixels field
   // (meaning it guarantees that the callback with be called).
   // In either case, the callback must be called exactly once, and the texture
   // must be deleted by the main thread context.
   struct Request : public base::RefCountedThreadSafe<Request> {
     Request(CopyTextureToImpl* impl,
             WebGLId texture_,
@@ skipping 37 matching lines @@
                                   WebGraphicsContext3D* context,
                                   scoped_refptr<base::TaskRunner> reply_loop);
   static void ReadBackFramebufferComplete(scoped_refptr<Request> request,
                                           bool result);
   void FinishRequest(scoped_refptr<Request> request);
   void CancelRequests();
 
   // Interleaved array of 2-dimentional vertex positions (x, y) and
   // 2-dimentional texture coordinates (s, t).
   static const WebKit::WGC3Dfloat kVertexAttributes[];
-  // Shader sources used for GLHelper::CopyTextureTo
+  // Shader sources used for GLHelper::CropScaleReadbackAndCleanTexture and
+  // GLHelper::ReadbackTextureSync
   static const WebKit::WGC3Dchar kCopyVertexShader[];
   static const WebKit::WGC3Dchar kCopyFragmentShader[];
 
   WebGraphicsContext3D* context_;
   WebGraphicsContext3D* context_for_thread_;
   GLHelper* helper_;
 
   // A scoped flush that will ensure all resource deletions are flushed when
   // this object is destroyed. Must be declared before other Scoped* fields.
   ScopedFlush flush_;
@@ skipping 147 matching lines @@
   if (!context_for_thread_)
     return;
 
   g_gl_helper_thread.Pointer()->message_loop_proxy()->PostTask(
       FROM_HERE,
       base::Bind(&DeleteContext,
                  context_for_thread_));
   context_for_thread_ = NULL;
 }
 
-void GLHelper::CopyTextureToImpl::CopyTextureTo(
+void GLHelper::CopyTextureToImpl::CropScaleReadbackAndCleanTexture(
     WebGLId src_texture,
     const gfx::Size& src_size,
     const gfx::Rect& src_subrect,
     const gfx::Size& dst_size,
     unsigned char* out,
     const base::Callback<void(bool)>& callback) {
   if (!context_for_thread_) {
     callback.Run(false);
     return;
   }
 
   WebGLId texture = ScaleTexture(src_texture, src_size, src_subrect, dst_size);
   context_->flush();
   scoped_refptr<Request> request =
       new Request(this, texture, dst_size, out, callback);
   request_queue_.push(request);
 
   g_gl_helper_thread.Pointer()->message_loop_proxy()->PostTask(FROM_HERE,
       base::Bind(&ReadBackFramebuffer,
                  request,
                  context_for_thread_,
                  base::MessageLoopProxy::current()));
 }
 
-WebKit::WebGLId GLHelper::CopyTextureToImpl::CopyTexture(
+void GLHelper::CopyTextureToImpl::ReadbackTextureSync(WebGLId texture,
+                                                      const gfx::Size& size,
+                                                      unsigned char* out) {
+  ScopedFramebuffer dst_framebuffer(context_, context_->createFramebuffer());
+  ScopedFramebufferBinder<GL_FRAMEBUFFER> framebuffer_binder(
+      context_, dst_framebuffer);
+  ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(context_, texture);
+  context_->framebufferTexture2D(GL_FRAMEBUFFER,
+                                 GL_COLOR_ATTACHMENT0,
+                                 GL_TEXTURE_2D,
+                                 texture,
+                                 0);
+  context_->readPixels(0,
+                       0,
+                       size.width(),
+                       size.height(),
+                       GL_RGBA,
+                       GL_UNSIGNED_BYTE,
+                       out);
+}
+
+WebKit::WebGLId GLHelper::CopyTextureToImpl::CopyAndScaleTexture(
     WebGLId src_texture,
-    const gfx::Size& size) {
-  if (!context_for_thread_)
-    return 0;
-  return ScaleTexture(src_texture, size, gfx::Rect(size), size);
+    const gfx::Size& src_size,
+    const gfx::Size& dst_size) {
+  return ScaleTexture(src_texture, src_size, gfx::Rect(src_size), dst_size);
 }
 
 void GLHelper::CopyTextureToImpl::ReadBackFramebuffer(
     scoped_refptr<Request> request,
     WebGraphicsContext3D* context,
     scoped_refptr<base::TaskRunner> reply_loop) {
   DCHECK(context);
   if (!context->makeContextCurrent() || context->isContextLost()) {
     base::AutoLock auto_lock(request->lock);
     if (request->pixels) {
@@ skipping 115 matching lines @@
     // http://crbug.com/125415
     base::ThreadRestrictions::ScopedAllowWait allow_wait;
     event.Wait();
   }
 }
 
 WebGraphicsContext3D* GLHelper::context() const {
   return context_;
 }
 
-void GLHelper::CopyTextureTo(WebGLId src_texture,
-                             const gfx::Size& src_size,
-                             const gfx::Rect& src_subrect,
-                             const gfx::Size& dst_size,
-                             unsigned char* out,
-                             const base::Callback<void(bool)>& callback) {
+void GLHelper::CropScaleReadbackAndCleanTexture(
+    WebGLId src_texture,
+    const gfx::Size& src_size,
+    const gfx::Rect& src_subrect,
+    const gfx::Size& dst_size,
+    unsigned char* out,
+    const base::Callback<void(bool)>& callback) {
   InitCopyTextToImpl();
-  copy_texture_to_impl_->CopyTextureTo(src_texture,
-                                       src_size,
-                                       src_subrect,
-                                       dst_size,
-                                       out,
-                                       callback);
+  copy_texture_to_impl_->CropScaleReadbackAndCleanTexture(src_texture,
+                                                          src_size,
+                                                          src_subrect,
+                                                          dst_size,
+                                                          out,
+                                                          callback);
+}
+
+void GLHelper::ReadbackTextureSync(WebKit::WebGLId texture,
+                                   const gfx::Size& size,
+                                   unsigned char* out) {
+  InitCopyTextToImpl();
+  copy_texture_to_impl_->ReadbackTextureSync(texture,
+                                             size,
+                                             out);
 }
 
 WebKit::WebGLId GLHelper::CopyTexture(WebKit::WebGLId texture,
                                       const gfx::Size& size) {
   InitCopyTextToImpl();
-  return copy_texture_to_impl_->CopyTexture(texture, size);
+  return copy_texture_to_impl_->CopyAndScaleTexture(texture, size, size);
+}
+
+WebKit::WebGLId GLHelper::CopyAndScaleTexture(WebKit::WebGLId texture,
+                                              const gfx::Size& src_size,
+                                              const gfx::Size& dst_size) {
+  InitCopyTextToImpl();
+  return copy_texture_to_impl_->CopyAndScaleTexture(texture,
+                                                    src_size,
+                                                    dst_size);
 }
 
 WebGLId GLHelper::CompileShaderFromSource(
     const WebKit::WGC3Dchar* source,
     WebKit::WGC3Denum type) {
   ScopedShader shader(context_, context_->createShader(type));
   context_->shaderSource(shader, source);
   context_->compileShader(shader);
   WebKit::WGC3Dint compile_status = 0;
   context_->getShaderiv(shader, GL_COMPILE_STATUS, &compile_status);
   if (!compile_status) {
     LOG(ERROR) << std::string(context_->getShaderInfoLog(shader).utf8());
     return 0;
   }
   return shader.Detach();
 }
 
 void GLHelper::InitCopyTextToImpl() {
   // Lazily initialize |copy_texture_to_impl_|
   if (!copy_texture_to_impl_.get())
     copy_texture_to_impl_.reset(new CopyTextureToImpl(context_,
                                                       context_for_thread_,
                                                       this));
 
 }
 
 }  // namespace content