flutter_flutter/compositor/layer_host.cc

// Copyright 2014 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 "sky/compositor/layer_host.h"

#include "base/debug/trace_event.h"
#include "base/message_loop/message_loop.h"
#include "mojo/converters/geometry/geometry_type_converters.h"
#include "mojo/gpu/gl_context.h"
#include "mojo/services/surfaces/public/cpp/surfaces_utils.h"
#include "mojo/skia/ganesh_context.h"
#include "sky/compositor/layer.h"

namespace sky {

LayerHost::LayerHost(LayerHostClient* client)
    : client_(client),
      state_(kReadyForFrame),
      frame_requested_(false),
      surface_holder_(this, client->GetShell()),
      gl_context_owner_(client->GetShell()),
      ganesh_context_(gl_context()),
      resource_manager_(gl_context()),
      weak_factory_(this) {
}

LayerHost::~LayerHost() {
}

void LayerHost::SetNeedsAnimate() {
  if (frame_requested_)
    return;
  frame_requested_ = true;
  if (state_ == kReadyForFrame)
    BeginFrameSoon();
}

void LayerHost::SetRootLayer(scoped_refptr<Layer> layer) {
  DCHECK(!root_layer_.get());
  root_layer_ = layer;
  root_layer_->set_host(this);
}

void LayerHost::GetPixelsForTesting(std::vector<unsigned char>* pixels) {
  return root_layer_->GetPixelsForTesting(pixels);
}

void LayerHost::OnSurfaceIdAvailable(mojo::SurfaceIdPtr surface_id) {
  client_->OnSurfaceIdAvailable(surface_id.Pass());
}

void LayerHost::ReturnResources(
    mojo::Array<mojo::ReturnedResourcePtr> resources) {
  resource_manager_.ReturnResources(resources.Pass());
}

void LayerHost::BeginFrameSoon() {
  base::MessageLoop::current()->PostTask(
      FROM_HERE,
      base::Bind(&LayerHost::BeginFrame, weak_factory_.GetWeakPtr()));
}

void LayerHost::BeginFrame() {
  TRACE_EVENT0("sky", "LayerHost::BeginFrame");

  DCHECK(frame_requested_);
  frame_requested_ = false;

  DCHECK_EQ(state_, kReadyForFrame);
  state_ = kWaitingForFrameAcknowldgement;

  client_->BeginFrame(base::TimeTicks::Now());

  // If the root layer is empty, there's no reason to draw into it. (In fact,
  // Ganesh will get upset if we try.) Instead, we just schedule the ack that
  // the frame is complete.
  if (root_layer_->size().IsEmpty()) {
    base::MessageLoop::current()->PostTask(
        FROM_HERE,
        base::Bind(&LayerHost::DidCompleteFrame, weak_factory_.GetWeakPtr()));
    return;
  }

  {
    mojo::GaneshContext::Scope scope(&ganesh_context_);
    ganesh_context_.gr()->resetContext();
    root_layer_->Display();
  }

  Upload(root_layer_.get());
}

void LayerHost::Upload(Layer* layer) {
  TRACE_EVENT0("sky", "LayerHost::Upload");

  gfx::Size size = layer->size();
  surface_holder_.SetSize(size);

  mojo::FramePtr frame = mojo::Frame::New();
  frame->resources.resize(0u);

  mojo::Rect bounds;
  bounds.width = size.width();
  bounds.height = size.height();
  mojo::PassPtr pass = mojo::CreateDefaultPass(1, bounds);
  pass->quads.resize(0u);
  pass->shared_quad_states.push_back(mojo::CreateDefaultSQS(
      mojo::TypeConverter<mojo::Size, gfx::Size>::Convert(size)));

  mojo::TransferableResourcePtr resource =
      resource_manager_.CreateTransferableResource(layer);

  mojo::QuadPtr quad = mojo::Quad::New();
  quad->material = mojo::MATERIAL_TEXTURE_CONTENT;

  mojo::RectPtr rect = mojo::Rect::New();
  rect->width = size.width();
  rect->height = size.height();
  quad->rect = rect.Clone();
  quad->opaque_rect = rect.Clone();
  quad->visible_rect = rect.Clone();
  quad->needs_blending = true;
  quad->shared_quad_state_index = 0u;

  mojo::TextureQuadStatePtr texture_state = mojo::TextureQuadState::New();
  texture_state->resource_id = resource->id;
  texture_state->premultiplied_alpha = true;
  texture_state->uv_top_left = mojo::PointF::New();
  texture_state->uv_bottom_right = mojo::PointF::New();
  texture_state->uv_bottom_right->x = 1.f;
  texture_state->uv_bottom_right->y = 1.f;
  texture_state->background_color = mojo::Color::New();
  texture_state->background_color->rgba = 0;
  for (int i = 0; i < 4; ++i)
    texture_state->vertex_opacity.push_back(1.f);
  texture_state->flipped = false;

  frame->resources.push_back(resource.Pass());
  quad->texture_quad_state = texture_state.Pass();
  pass->quads.push_back(quad.Pass());

  frame->passes.push_back(pass.Pass());
  surface_holder_.SubmitFrame(
      frame.Pass(),
      base::Bind(&LayerHost::DidCompleteFrame, weak_factory_.GetWeakPtr()));
}

void LayerHost::DidCompleteFrame() {
  DCHECK_EQ(state_, kWaitingForFrameAcknowldgement);
  state_ = kReadyForFrame;
  if (frame_requested_)
    BeginFrame();
}

}  // namespace sky