[cc] Mailbox Output Surface Support

content/renderer/gpu/mailbox_output_surface.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/renderer/gpu/mailbox_output_surface.h"
+
+#include "base/logging.h"
+#include "cc/compositor_frame.h"
+#include "cc/compositor_frame_ack.h"
+#include "cc/gl_frame_data.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebGraphicsContext3D.h"
+#include "third_party/khronos/GLES2/gl2.h"
+#include "third_party/khronos/GLES2/gl2ext.h"
+
+using cc::CompositorFrame;
+using cc::GLFrameData;
+using cc::Mailbox;
+using WebKit::WebGraphicsContext3D;
+
+namespace content {
+
+MailboxOutputSurface::MailboxOutputSurface(
+    int32 routing_id,
+    WebGraphicsContext3D* context3D,
+    cc::SoftwareOutputDevice* software_device)
+    : CompositorOutputSurface(routing_id,
+                              context3D,
+                              software_device),
+  fbo_(0) {
+}
+
+MailboxOutputSurface::~MailboxOutputSurface() {
+  DiscardBackbuffer();
+}
+
+void MailboxOutputSurface::EnsureBackbuffer() {
+  if (!current_backing_.texture_id) {
+    // Find a texture of matching size to recycle.
+    while (returned_textures_.size()) {

[piman, 2013/02/27 23:51:04]

!returned_textures_.empty()

[no sievers, 2013/02/28 18:43:40]

Done.

+      TransferableFrame& texture = returned_textures_.front();
+      if (texture.size == size_) {
+        current_backing_ = texture;
+        returned_textures_.pop();
+        break;
+      }
+
+      context3d_->deleteTexture(texture.texture_id);
+      returned_textures_.pop();
+    }
+
+    if (!current_backing_.texture_id) {
+      current_backing_.texture_id = context3d_->createTexture();
+      current_backing_.size = size_;
+      context3d_->genMailboxCHROMIUM(current_backing_.mailbox.name);
+      context3d_->bindTexture(GL_TEXTURE_2D, current_backing_.texture_id);
+      context3d_->texParameteri(
+          GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+      context3d_->texParameteri(
+          GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+      context3d_->texParameteri(
+          GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+      context3d_->texParameteri(
+          GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+      context3d_->texImage2D(
+          GL_TEXTURE_2D, 0, GL_RGBA, size_.width(), size_.height(), 0,
+          GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+    }
+  }
+}
+
+void MailboxOutputSurface::DiscardBackbuffer() {
+  if (current_backing_.texture_id) {
+    context3d_->deleteTexture(current_backing_.texture_id);
+    current_backing_ = TransferableFrame();
+  }
+
+  while (returned_textures_.size()) {

[piman, 2013/02/27 23:51:04]

!returned_textures_.empty()

[no sievers, 2013/02/28 18:43:40]

Done.

+    context3d_->deleteTexture(returned_textures_.front().texture_id);
+    returned_textures_.pop();
+  }
+
+  if (fbo_) {
+    context3d_->bindFramebuffer(GL_FRAMEBUFFER, fbo_);
+    context3d_->deleteFramebuffer(fbo_);
+    fbo_ = 0;
+  }
+}
+
+void MailboxOutputSurface::Reshape(const gfx::Size& size) {
+  size_ = size;

[Sami, 2013/02/28 12:46:58]

Should we DCHECK here that size_ != size? Hopefully we're not doing this
uselessly.

[no sievers, 2013/02/28 18:43:40]

I added an early-return.

+  DiscardBackbuffer();
+  EnsureBackbuffer();
+}
+
+void MailboxOutputSurface::BindFramebuffer() {
+  EnsureBackbuffer();
+  DCHECK(current_backing_.texture_id);
+
+  if (!fbo_)
+     fbo_ = context3d_->createFramebuffer();

[Sami, 2013/02/28 12:46:58]

Nit: indent by 2.

[no sievers, 2013/02/28 18:43:40]

Done.

+  context3d_->bindFramebuffer(GL_FRAMEBUFFER, fbo_);
+  context3d_->framebufferTexture2D(
+      GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+      current_backing_.texture_id, 0);
+}
+
+void MailboxOutputSurface::SendFrameToParentCompositor(
+    cc::CompositorFrame* frame) {
+  frame->gl_frame_data.reset(new GLFrameData());
+
+  DCHECK(!size_.IsEmpty());
+  DCHECK(size_ == current_backing_.size);
+  DCHECK(!current_backing_.mailbox.isZero());
+
+  context3d_->framebufferTexture2D(
+      GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 0, 0);
+  context3d_->bindTexture(GL_TEXTURE_2D, current_backing_.texture_id);
+  context3d_->produceTextureCHROMIUM(
+      GL_TEXTURE_2D, current_backing_.mailbox.name);
+  frame->gl_frame_data->mailbox = current_backing_.mailbox;
+  frame->gl_frame_data->size = current_backing_.size;
+  context3d_->flush();
+  frame->gl_frame_data->sync_point = context3d_->insertSyncPoint();
+  context3d_->deleteTexture(current_backing_.texture_id);

[piman, 2013/02/27 23:51:04]

note: for a follow-up probably, but you may want to keep the texture around, to
avoid having to recreate it (it's non-trivial).

[no sievers, 2013/02/28 18:43:40]

TODO added.

+  current_backing_ = TransferableFrame();
+  CompositorOutputSurface::SendFrameToParentCompositor(frame);

[piman, 2013/02/27 23:51:04]

nit: can you move this above the deleteTexture? It does non trivial work (lock,
flush) in the possibly latency-sensitive path.

[no sievers, 2013/02/28 18:43:40]

Done.

+}
+
+void MailboxOutputSurface::OnSwapAck(const cc::CompositorFrameAck& ack) {
+  if (!ack.gl_frame_data->mailbox.isZero()) {
+    DCHECK(!ack.gl_frame_data->size.IsEmpty());
+    uint32 texture_id = context3d_->createTexture();
+    TransferableFrame texture(
+        texture_id, ack.gl_frame_data->mailbox, ack.gl_frame_data->size);
+
+    context3d_->bindTexture(GL_TEXTURE_2D, texture_id);
+
+    // If the consumer is bouncing back the same texture (i.e. skipping the
+    // frame), we don't have to synchronize here (sync_point == 0).
+    if (ack.gl_frame_data->sync_point)
+      context3d_->waitSyncPoint(ack.gl_frame_data->sync_point);

[piman, 2013/02/27 23:51:04]

note: a potential optimization (for a follow-up too) is to not wait/consume
until you reuse the texture, to avoid over-constraining the renderer.

[no sievers, 2013/02/28 18:43:40]

TODO added.

+
+    context3d_->consumeTextureCHROMIUM(
+        GL_TEXTURE_2D, ack.gl_frame_data->mailbox.name);
+    returned_textures_.push(texture);
+  }
+  CompositorOutputSurface::OnSwapAck(ack);
+}
+
+void MailboxOutputSurface::SwapBuffers() {
+}
+
+void MailboxOutputSurface::PostSubBuffer(const gfx::Rect& rect) {
+  NOTIMPLEMENTED()
+      << "Partial swap not supported with composite-to-mailbox yet.";
+}
+
+}  // namespace content