Use inner HWND for accelerated rendering on windows

chrome/gpu/gpu_command_buffer_stub.cc

Index: chrome/gpu/gpu_command_buffer_stub.cc
===================================================================
--- chrome/gpu/gpu_command_buffer_stub.cc	(revision 66799)
+++ chrome/gpu/gpu_command_buffer_stub.cc	(working copy)
@@ -14,6 +14,8 @@
 
 using gpu::Buffer;
 
+#define kCompositorWindowOwner L"CompositorWindowOwner"
+
 GpuCommandBufferStub::GpuCommandBufferStub(
     GpuChannel* channel,
     gfx::PluginWindowHandle handle,
@@ -38,10 +40,122 @@
       render_view_id_(render_view_id) {
 }
 
+#if defined(OS_WIN)
+static LRESULT CALLBACK CompositorWindowProc(
+    HWND hwnd,
+    UINT message,
+    WPARAM wparam,
+    LPARAM lparam) {
+  switch (message) {
+    case WM_ERASEBKGND:
+      return 0;
+    case WM_DESTROY:
+      return 0;
+    case WM_PAINT: {
+      PAINTSTRUCT paint;
+      HDC dc = BeginPaint(hwnd, &paint);
+      if (dc) {
+        HANDLE h = GetProp(hwnd, kCompositorWindowOwner);
+        if (h) {
+          GpuCommandBufferStub* stub =
+              reinterpret_cast<GpuCommandBufferStub*>(h);
+          stub->OnCompositorWindowPainted();
+          EndPaint(hwnd, &paint);

[apatrick_chromium, 2010/11/22 20:43:03]

EndPaint needs to be matched with every successful BeginPaint so it should be
outside of the if (h) { block.

[nduca, 2010/11/22 22:37:44]

Done.

+        }
+      }
+      break;
+    }
+    default:
+      return DefWindowProc(hwnd, message, wparam, lparam);
+  }
+  return 0;
+}
+
+bool GpuCommandBufferStub::CreateCompositorWindow() {
+  DCHECK(handle_ != gfx::kNullPluginWindow);
+
+  // Ask the browser to create the the host window.
+  ChildThread* gpu_thread = ChildThread::current();
+  gfx::PluginWindowHandle host_window_id;
+    gpu_thread->Send(new GpuHostMsg_CreateCompositorHostWindow(

[apatrick_chromium, 2010/11/22 20:43:03]

indentation is out.

[nduca, 2010/11/22 22:37:44]

Done.

+      renderer_id_,
+      render_view_id_,
+      &host_window_id));
+  HWND host_window = static_cast<HWND>(host_window_id);
+
+  // Create the compositor window itself.
+  DCHECK(host_window);
+  static ATOM window_class = 0;
+  if (!window_class) {
+    WNDCLASSEX wcex;
+    wcex.cbSize         = sizeof(wcex);
+    wcex.style          = 0;
+    wcex.lpfnWndProc    = CompositorWindowProc;
+    wcex.cbClsExtra     = 0;
+    wcex.cbWndExtra     = 0;
+    wcex.hInstance      = GetModuleHandle(NULL);
+    wcex.hIcon          = 0;
+    wcex.hCursor        = 0;
+    wcex.hbrBackground  = NULL;
+    wcex.lpszMenuName   = 0;
+    wcex.lpszClassName  = L"CompositorWindowClass";
+    wcex.hIconSm        = 0;
+    window_class = RegisterClassEx(&wcex);
+    DCHECK(window_class);
+  }
+
+  HWND compositor_window = CreateWindowEx(
+      WS_EX_LEFT | WS_EX_LTRREADING | WS_EX_RIGHTSCROLLBAR,
+      MAKEINTATOM(window_class),
+      0,
+      WS_CHILD | WS_CLIPCHILDREN | WS_CLIPSIBLINGS | WS_DISABLED,
+      0, 0,
+      0, 0,
+      host_window,
+      0,
+      GetModuleHandle(NULL),
+      0);
+  if (!compositor_window) {
+    compositor_window_ = gfx::kNullPluginWindow;
+    return false;
+  }
+  SetProp(compositor_window, kCompositorWindowOwner,
+      reinterpret_cast<HANDLE>(this));
+
+  RECT parent_rect;
+  GetClientRect(host_window, &parent_rect);
+
+  UINT flags = SWP_NOSENDCHANGING | SWP_NOCOPYBITS | SWP_NOZORDER |
+      SWP_NOACTIVATE | SWP_DEFERERASE | SWP_SHOWWINDOW;
+  SetWindowPos(compositor_window,
+      NULL,
+      0, 0,
+      parent_rect.right - parent_rect.left,
+      parent_rect.bottom - parent_rect.top,
+      flags);
+  compositor_window_ = static_cast<gfx::PluginWindowHandle>(compositor_window);
+  return true;
+}
+
+void GpuCommandBufferStub::OnCompositorWindowPainted() {
+  ChildThread* gpu_thread = ChildThread::current();
+  gpu_thread->Send(new GpuHostMsg_ScheduleComposite(
+      renderer_id_, render_view_id_));
+}
+#endif  // defined(OS_WIN)
+
+
 GpuCommandBufferStub::~GpuCommandBufferStub() {
   if (processor_.get()) {
     processor_->Destroy();
   }
+#if defined(OS_WIN)
+  if (compositor_window_) {
+    RemoveProp(compositor_window_, kCompositorWindowOwner);
+    DestroyWindow(static_cast<HWND>(compositor_window_));
+    compositor_window_ = NULL;
+  }
+#endif
 }
 
 void GpuCommandBufferStub::OnMessageReceived(const IPC::Message& message) {
@@ -79,6 +193,22 @@
 
   command_buffer_.reset(new gpu::CommandBufferService);
 
+  // Create the child window, if needed
+#if defined(OS_WIN)
+  gfx::PluginWindowHandle output_window_handle;
+  if (handle_) {
+    if (!CreateCompositorWindow()) {
+      *ring_buffer = NULL;

[apatrick_chromium, 2010/11/22 20:43:03]

We use base::SharedMemory::NULLHandle() instead of null because it works on all
platforms. I don't think you need this assignment though, it's initialized to
the null handle up top.

[nduca, 2010/11/22 22:37:44]

Done.

+      return;
+    }
+    handle_ = compositor_window_;
+  } else {
+    output_window_handle = handle_;
+  }
+#else
+  gfx::PluginWindowHandle output_window_handle = handle_;
+#endif
+
   // Initialize the CommandBufferService and GPUProcessor.
   if (command_buffer_->Initialize(size)) {
     Buffer buffer = command_buffer_->GetRingBuffer();
@@ -87,7 +217,7 @@
           parent_ ? parent_->processor_.get() : NULL;
       processor_.reset(new gpu::GPUProcessor(command_buffer_.get(), NULL));
       if (processor_->Initialize(
-          handle_,
+          output_window_handle,
           initial_size_,
           allowed_extensions_.c_str(),
           requested_attribs_,