Initial checkin of the new Mozart compositor.

services/gfx/compositor/backend/gpu_rasterizer.cc

+// Copyright 2015 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 "services/gfx/compositor/backend/gpu_rasterizer.h"
+
+#ifndef GL_GLEXT_PROTOTYPES
+#define GL_GLEXT_PROTOTYPES
+#endif
+
+#include <GLES2/gl2.h>
+#include <GLES2/gl2extmojo.h>
+#include <MGL/mgl.h>
+#include <MGL/mgl_onscreen.h>
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "services/gfx/compositor/backend/vsync_scheduler.h"
+#include "services/gfx/compositor/render/render_frame.h"
+
+namespace compositor {
+
+GpuRasterizer::GpuRasterizer(mojo::ContextProviderPtr context_provider,
+                             const std::shared_ptr<VsyncScheduler>& scheduler,
+                             const scoped_refptr<base::TaskRunner>& task_runner,
+                             const base::Closure& error_callback)
+    : context_provider_(context_provider.Pass()),
+      scheduler_(scheduler),
+      task_runner_(task_runner),
+      error_callback_(error_callback),
+      viewport_parameter_listener_binding_(this) {
+  DCHECK(context_provider_);
+  context_provider_.set_connection_error_handler(
+      base::Bind(&GpuRasterizer::OnContextProviderConnectionError,
+                 base::Unretained(this)));
+  CreateContext();
+}
+
+GpuRasterizer::~GpuRasterizer() {
+  DestroyContext();
+}
+
+void GpuRasterizer::CreateContext() {
+  mojo::ViewportParameterListenerPtr viewport_parameter_listener;
+  viewport_parameter_listener_binding_.Bind(
+      GetProxy(&viewport_parameter_listener));
+  context_provider_->Create(
+      viewport_parameter_listener.Pass(),
+      base::Bind(&GpuRasterizer::InitContext, base::Unretained(this)));
+}
+
+void GpuRasterizer::InitContext(mojo::CommandBufferPtr command_buffer) {
+  DCHECK(!gl_context_);
+  DCHECK(!ganesh_context_);
+  DCHECK(!ganesh_surface_);
+
+  if (!command_buffer) {
+    LOG(ERROR) << "Could not create GL context.";
+    PostErrorCallback();
+    return;
+  }
+
+  gl_context_ = mojo::GLContext::CreateFromCommandBuffer(command_buffer.Pass());
+  gl_context_->AddObserver(this);
+  ganesh_context_.reset(new mojo::skia::GaneshContext(gl_context_));
+
+  if (current_frame_)
+    Draw();
+}
+
+void GpuRasterizer::DestroyContext() {
+  if (gl_context_) {
+    scheduler_->Stop();
+
+    // Release objects that belong to special scopes.
+    {
+      mojo::skia::GaneshContext::Scope ganesh_scope(ganesh_context_.get());
+      PaintingScope painting_scope(ganesh_scope, &painting_cache_);
+      ganesh_surface_.reset();
+      painting_cache_.Clear(painting_scope);
+    }
+
+    // Release the ganesh context first.
+    ganesh_context_.reset();
+
+    // Now release the GL context.
+    gl_context_->Destroy();
+    gl_context_.reset();
+  }
+}
+
+void GpuRasterizer::OnContextProviderConnectionError() {
+  LOG(ERROR) << "Context provider connection lost.";
+  PostErrorCallback();
+}
+
+void GpuRasterizer::OnContextLost() {
+  LOG(WARNING) << "GL context lost, recreating it.";
+  DestroyContext();
+  CreateContext();
+}
+
+void GpuRasterizer::OnVSyncParametersUpdated(int64_t timebase,
+                                             int64_t interval) {
+  DVLOG(1) << "Vsync parameters: timebase=" << timebase
+           << ", interval=" << interval;
+
+  if (!gl_context_)
+    return;
+
+  // TODO(jeffbrown): This shouldn't be hardcoded.
+  // Need to do some real tuning and possibly determine values adaptively.
+  int64_t update_phase = -interval;
+  int64_t snapshot_phase = -interval / 8;
+  int64_t presentation_phase = interval;
+  if (!scheduler_->Start(timebase, interval, update_phase, snapshot_phase,
+                         presentation_phase)) {
+    LOG(ERROR) << "Received invalid vsync parameters: timebase=" << timebase
+               << ", interval=" << interval;
+    PostErrorCallback();
+  }
+}
+
+void GpuRasterizer::SubmitFrame(const std::shared_ptr<RenderFrame>& frame) {
+  DCHECK(frame);
+
+  if (current_frame_ == frame)
+    return;
+
+  current_frame_ = frame;
+  if (gl_context_)
+    Draw();
+}
+
+void GpuRasterizer::Draw() {
+  DCHECK(gl_context_);
+  DCHECK(ganesh_context_);
+  DCHECK(current_frame_);
+
+  gl_context_->MakeCurrent();
+
+  // Update the viewport.
+  const SkRect& viewport = current_frame_->viewport();
+  bool stale_surface = false;
+  if (!ganesh_surface_ ||
+      ganesh_surface_->surface()->width() != viewport.width() ||
+      ganesh_surface_->surface()->height() != viewport.height()) {
+    glViewport(viewport.x(), viewport.y(), viewport.width(), viewport.height());
+    glResizeCHROMIUM(viewport.width(), viewport.height(), 1.0f);
+    stale_surface = true;
+  }
+
+  // Paint the frame.
+  {
+    mojo::skia::GaneshContext::Scope ganesh_scope(ganesh_context_.get());
+    PaintingScope painting_scope(ganesh_scope, &painting_cache_);
+
+    if (stale_surface)
+      ganesh_surface_.reset(
+          new mojo::skia::GaneshFramebufferSurface(ganesh_scope));
+
+    current_frame_->Paint(painting_scope, ganesh_surface_->canvas());
+  }
+
+  // Swap buffers.
+  MGLSwapBuffers();
+}

[abarth, 2016/01/10 04:22:09]

Usually you want some sort of signal to come out of here.  Knowing when the swap
completes lets you throttle work earlier in the pipeline.  I guess I haven't
seen where the backpressure gets applied yet.

[jeffbrown, 2016/01/16 03:28:31]

It doesn't.  :)

I'll fix this later, as we discussed.

+
+void GpuRasterizer::PostErrorCallback() {
+  task_runner_->PostTask(FROM_HERE, error_callback_);
+}
+
+}  // namespace compositor