cc/output/direct_renderer.cc - mojo-tools - Git at Google

 // Copyright 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 "cc/output/direct_renderer.h"

 #include <utility>
 #include <vector>

 #include "base/containers/hash_tables.h"
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/metrics/histogram.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/base/math_util.h"
 #include "cc/output/copy_output_request.h"
 #include "cc/quads/draw_quad.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/gfx/transform.h"

 static gfx::Transform OrthoProjectionMatrix(float left,
                                             float right,
                                             float bottom,
                                             float top) {
   // Use the standard formula to map the clipping frustum to the cube from
   // [-1, -1, -1] to [1, 1, 1].
   float delta_x = right - left;
   float delta_y = top - bottom;
   gfx::Transform proj;
   if (!delta_x || !delta_y)
     return proj;
   proj.matrix().set(0, 0, 2.0f / delta_x);
   proj.matrix().set(0, 3, -(right + left) / delta_x);
   proj.matrix().set(1, 1, 2.0f / delta_y);
   proj.matrix().set(1, 3, -(top + bottom) / delta_y);

   // Z component of vertices is always set to zero as we don't use the depth
   // buffer while drawing.
   proj.matrix().set(2, 2, 0);

   return proj;
 }

 static gfx::Transform window_matrix(int x, int y, int width, int height) {
   gfx::Transform canvas;

   // Map to window position and scale up to pixel coordinates.
   canvas.Translate3d(x, y, 0);
   canvas.Scale3d(width, height, 0);

   // Map from ([-1, -1] to [1, 1]) -> ([0, 0] to [1, 1])
   canvas.Translate3d(0.5, 0.5, 0.5);
   canvas.Scale3d(0.5, 0.5, 0.5);

   return canvas;
 }

 namespace cc {

 DirectRenderer::DrawingFrame::DrawingFrame()
     : root_render_pass(NULL), current_render_pass(NULL), current_texture(NULL) {
 }

 DirectRenderer::DrawingFrame::~DrawingFrame() {}

 //
 // static
 gfx::RectF DirectRenderer::QuadVertexRect() {
   return gfx::RectF(-0.5f, -0.5f, 1.f, 1.f);
 }

 // static
 void DirectRenderer::QuadRectTransform(gfx::Transform* quad_rect_transform,
                                        const gfx::Transform& quad_transform,
                                        const gfx::RectF& quad_rect) {
   *quad_rect_transform = quad_transform;
   quad_rect_transform->Translate(0.5 * quad_rect.width() + quad_rect.x(),
                                  0.5 * quad_rect.height() + quad_rect.y());
   quad_rect_transform->Scale(quad_rect.width(), quad_rect.height());
 }

 void DirectRenderer::InitializeViewport(DrawingFrame* frame,
                                         const gfx::Rect& draw_rect,
                                         const gfx::Rect& viewport_rect,
                                         const gfx::Size& surface_size) {
   DCHECK_GE(viewport_rect.x(), 0);
   DCHECK_GE(viewport_rect.y(), 0);
   DCHECK_LE(viewport_rect.right(), surface_size.width());
   DCHECK_LE(viewport_rect.bottom(), surface_size.height());
   bool flip_y = FlippedFramebuffer(frame);
   if (flip_y) {
     frame->projection_matrix = OrthoProjectionMatrix(draw_rect.x(),
                                                      draw_rect.right(),
                                                      draw_rect.bottom(),
                                                      draw_rect.y());
   } else {
     frame->projection_matrix = OrthoProjectionMatrix(draw_rect.x(),
                                                      draw_rect.right(),
                                                      draw_rect.y(),
                                                      draw_rect.bottom());
   }

   gfx::Rect window_rect = viewport_rect;
   if (flip_y)
     window_rect.set_y(surface_size.height() - viewport_rect.bottom());
   frame->window_matrix = window_matrix(window_rect.x(),
                                        window_rect.y(),
                                        window_rect.width(),
                                        window_rect.height());
   SetDrawViewport(window_rect);

   current_draw_rect_ = draw_rect;
   current_viewport_rect_ = viewport_rect;
   current_surface_size_ = surface_size;
 }

 gfx::Rect DirectRenderer::MoveFromDrawToWindowSpace(
     const DrawingFrame* frame,
     const gfx::Rect& draw_rect) const {
   gfx::Rect window_rect = draw_rect;
   window_rect -= current_draw_rect_.OffsetFromOrigin();
   window_rect += current_viewport_rect_.OffsetFromOrigin();
   if (FlippedFramebuffer(frame))
     window_rect.set_y(current_surface_size_.height() - window_rect.bottom());
   return window_rect;
 }

 DirectRenderer::DirectRenderer(RendererClient* client,
                                const RendererSettings* settings,
                                OutputSurface* output_surface,
                                ResourceProvider* resource_provider)
     : Renderer(client, settings),
       output_surface_(output_surface),
       resource_provider_(resource_provider),
       overlay_processor_(
           new OverlayProcessor(output_surface, resource_provider)) {
   overlay_processor_->Initialize();
 }

 DirectRenderer::~DirectRenderer() {}

 void DirectRenderer::SetEnlargePassTextureAmountForTesting(
     const gfx::Vector2d& amount) {
   enlarge_pass_texture_amount_ = amount;
 }

 void DirectRenderer::DecideRenderPassAllocationsForFrame(
     const RenderPassList& render_passes_in_draw_order) {
   if (!resource_provider_)
     return;

   base::hash_map<RenderPassId, gfx::Size> render_passes_in_frame;
   for (size_t i = 0; i < render_passes_in_draw_order.size(); ++i)
     render_passes_in_frame.insert(std::pair<RenderPassId, gfx::Size>(
         render_passes_in_draw_order[i]->id,
         RenderPassTextureSize(render_passes_in_draw_order[i])));

   std::vector<RenderPassId> passes_to_delete;
   base::ScopedPtrHashMap<RenderPassId, ScopedResource>::const_iterator
       pass_iter;
   for (pass_iter = render_pass_textures_.begin();
        pass_iter != render_pass_textures_.end();
        ++pass_iter) {
     base::hash_map<RenderPassId, gfx::Size>::const_iterator it =
         render_passes_in_frame.find(pass_iter->first);
     if (it == render_passes_in_frame.end()) {
       passes_to_delete.push_back(pass_iter->first);
       continue;
     }

     gfx::Size required_size = it->second;
     ScopedResource* texture = pass_iter->second;
     DCHECK(texture);

     bool size_appropriate = texture->size().width() >= required_size.width() &&
                             texture->size().height() >= required_size.height();
     if (texture->id() && !size_appropriate)
       texture->Free();
   }

   // Delete RenderPass textures from the previous frame that will not be used
   // again.
   for (size_t i = 0; i < passes_to_delete.size(); ++i)
     render_pass_textures_.erase(passes_to_delete[i]);

   for (size_t i = 0; i < render_passes_in_draw_order.size(); ++i) {
     if (!render_pass_textures_.contains(render_passes_in_draw_order[i]->id)) {
       scoped_ptr<ScopedResource> texture =
           ScopedResource::Create(resource_provider_);
       render_pass_textures_.set(render_passes_in_draw_order[i]->id,
                               texture.Pass());
     }
   }
 }

 void DirectRenderer::DrawFrame(RenderPassList* render_passes_in_draw_order,
                                float device_scale_factor,
                                const gfx::Rect& device_viewport_rect,
                                const gfx::Rect& device_clip_rect,
                                bool disable_picture_quad_image_filtering) {
   TRACE_EVENT0("cc", "DirectRenderer::DrawFrame");
   UMA_HISTOGRAM_COUNTS("Renderer4.renderPassCount",
                        render_passes_in_draw_order->size());

   const RenderPass* root_render_pass = render_passes_in_draw_order->back();
   DCHECK(root_render_pass);

   DrawingFrame frame;
   frame.render_passes_in_draw_order = render_passes_in_draw_order;
   frame.root_render_pass = root_render_pass;
   frame.root_damage_rect = Capabilities().using_partial_swap
                                ? root_render_pass->damage_rect
                                : root_render_pass->output_rect;
   frame.root_damage_rect.Intersect(gfx::Rect(device_viewport_rect.size()));
   frame.device_viewport_rect = device_viewport_rect;
   frame.device_clip_rect = device_clip_rect;
   frame.disable_picture_quad_image_filtering =
       disable_picture_quad_image_filtering;

   overlay_processor_->ProcessForOverlays(render_passes_in_draw_order,
                                          &frame.overlay_list);

   EnsureBackbuffer();

   // Only reshape when we know we are going to draw. Otherwise, the reshape
   // can leave the window at the wrong size if we never draw and the proper
   // viewport size is never set.
   output_surface_->Reshape(device_viewport_rect.size(), device_scale_factor);

   BeginDrawingFrame(&frame);
   for (size_t i = 0; i < render_passes_in_draw_order->size(); ++i) {
     RenderPass* pass = render_passes_in_draw_order->at(i);
     DrawRenderPass(&frame, pass);

     for (ScopedPtrVector<CopyOutputRequest>::iterator it =
              pass->copy_requests.begin();
          it != pass->copy_requests.end();
          ++it) {
       if (i > 0) {
         // Doing a readback is destructive of our state on Mac, so make sure
         // we restore the state between readbacks. http://crbug.com/99393.
         UseRenderPass(&frame, pass);
       }
       CopyCurrentRenderPassToBitmap(&frame, pass->copy_requests.take(it));
     }
   }
   FinishDrawingFrame(&frame);

   render_passes_in_draw_order->clear();
 }

 gfx::Rect DirectRenderer::ComputeScissorRectForRenderPass(
     const DrawingFrame* frame) {
   gfx::Rect render_pass_scissor = frame->current_render_pass->output_rect;

   if (frame->root_damage_rect == frame->root_render_pass->output_rect ||
       !frame->current_render_pass->copy_requests.empty())
     return render_pass_scissor;

   gfx::Transform inverse_transform(gfx::Transform::kSkipInitialization);
   if (frame->current_render_pass->transform_to_root_target.GetInverse(
           &inverse_transform)) {
     // Only intersect inverse-projected damage if the transform is invertible.
     gfx::Rect damage_rect_in_render_pass_space =
         MathUtil::ProjectEnclosingClippedRect(inverse_transform,
                                               frame->root_damage_rect);
     render_pass_scissor.Intersect(damage_rect_in_render_pass_space);
   }

   return render_pass_scissor;
 }

 bool DirectRenderer::NeedDeviceClip(const DrawingFrame* frame) const {
   if (frame->current_render_pass != frame->root_render_pass)
     return false;

   return !frame->device_clip_rect.Contains(frame->device_viewport_rect);
 }

 gfx::Rect DirectRenderer::DeviceClipRectInWindowSpace(const DrawingFrame* frame)
     const {
   gfx::Rect device_clip_rect = frame->device_clip_rect;
   if (FlippedFramebuffer(frame))
     device_clip_rect.set_y(current_surface_size_.height() -
                            device_clip_rect.bottom());
   return device_clip_rect;
 }

 void DirectRenderer::SetScissorStateForQuad(const DrawingFrame* frame,
                                             const DrawQuad& quad) {
   if (quad.isClipped()) {
     SetScissorTestRectInDrawSpace(frame, quad.clipRect());
     return;
   }
   if (NeedDeviceClip(frame)) {
     SetScissorTestRect(DeviceClipRectInWindowSpace(frame));
     return;
   }

   EnsureScissorTestDisabled();
 }

 void DirectRenderer::SetScissorStateForQuadWithRenderPassScissor(
     const DrawingFrame* frame,
     const DrawQuad& quad,
     const gfx::Rect& render_pass_scissor,
     bool* should_skip_quad) {
   gfx::Rect quad_scissor_rect = render_pass_scissor;

   if (quad.isClipped())
     quad_scissor_rect.Intersect(quad.clipRect());

   if (quad_scissor_rect.IsEmpty()) {
     *should_skip_quad = true;
     return;
   }

   *should_skip_quad = false;
   SetScissorTestRectInDrawSpace(frame, quad_scissor_rect);
 }

 void DirectRenderer::SetScissorTestRectInDrawSpace(
     const DrawingFrame* frame,
     const gfx::Rect& draw_space_rect) {
   gfx::Rect window_space_rect =
       MoveFromDrawToWindowSpace(frame, draw_space_rect);
   if (NeedDeviceClip(frame))
     window_space_rect.Intersect(DeviceClipRectInWindowSpace(frame));
   SetScissorTestRect(window_space_rect);
 }

 void DirectRenderer::FinishDrawingQuadList() {}

 void DirectRenderer::DrawRenderPass(DrawingFrame* frame,
                                     const RenderPass* render_pass) {
   TRACE_EVENT0("cc", "DirectRenderer::DrawRenderPass");
   if (!UseRenderPass(frame, render_pass))
     return;

   bool using_scissor_as_optimization = Capabilities().using_partial_swap;
   gfx::Rect render_pass_scissor;
   bool draw_rect_covers_full_surface = true;
   if (frame->current_render_pass == frame->root_render_pass &&
       !frame->device_viewport_rect.Contains(
            gfx::Rect(output_surface_->SurfaceSize())))
     draw_rect_covers_full_surface = false;

   if (using_scissor_as_optimization) {
     render_pass_scissor = ComputeScissorRectForRenderPass(frame);
     SetScissorTestRectInDrawSpace(frame, render_pass_scissor);
     if (!render_pass_scissor.Contains(frame->current_render_pass->output_rect))
       draw_rect_covers_full_surface = false;
   }

   if (frame->current_render_pass != frame->root_render_pass ||
       settings_->should_clear_root_render_pass) {
     if (NeedDeviceClip(frame)) {
       SetScissorTestRect(DeviceClipRectInWindowSpace(frame));
       draw_rect_covers_full_surface = false;
     } else if (!using_scissor_as_optimization) {
       EnsureScissorTestDisabled();
     }

     bool has_external_stencil_test =
         output_surface_->HasExternalStencilTest() &&
         frame->current_render_pass == frame->root_render_pass;

     DiscardPixels(has_external_stencil_test, draw_rect_covers_full_surface);
     ClearFramebuffer(frame, has_external_stencil_test);
   }

   const QuadList& quad_list = render_pass->quad_list;
   for (auto it = quad_list.BackToFrontBegin(); it != quad_list.BackToFrontEnd();
        ++it) {
     const DrawQuad& quad = **it;
     bool should_skip_quad = false;

     if (using_scissor_as_optimization) {
       SetScissorStateForQuadWithRenderPassScissor(
           frame, quad, render_pass_scissor, &should_skip_quad);
     } else {
       SetScissorStateForQuad(frame, quad);
     }

     if (!should_skip_quad)
       DoDrawQuad(frame, &quad);
   }
   FinishDrawingQuadList();
 }

 bool DirectRenderer::UseRenderPass(DrawingFrame* frame,
                                    const RenderPass* render_pass) {
   frame->current_render_pass = render_pass;
   frame->current_texture = NULL;

   if (render_pass == frame->root_render_pass) {
     BindFramebufferToOutputSurface(frame);
     InitializeViewport(frame,
                        render_pass->output_rect,
                        frame->device_viewport_rect,
                        output_surface_->SurfaceSize());
     return true;
   }

   ScopedResource* texture = render_pass_textures_.get(render_pass->id);
   DCHECK(texture);

   gfx::Size size = RenderPassTextureSize(render_pass);
   size.Enlarge(enlarge_pass_texture_amount_.x(),
                enlarge_pass_texture_amount_.y());
   if (!texture->id())
     texture->Allocate(
         size, ResourceProvider::TextureHintImmutableFramebuffer, RGBA_8888);
   DCHECK(texture->id());

   return BindFramebufferToTexture(frame, texture, render_pass->output_rect);
 }

 bool DirectRenderer::HasAllocatedResourcesForTesting(RenderPassId id) const {
   ScopedResource* texture = render_pass_textures_.get(id);
   return texture && texture->id();
 }

 // static
 gfx::Size DirectRenderer::RenderPassTextureSize(const RenderPass* render_pass) {
   return render_pass->output_rect.size();
 }

 }  // namespace cc
	// Copyright 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 "cc/output/direct_renderer.h"

	#include <utility>
	#include <vector>

	#include "base/containers/hash_tables.h"
	#include "base/containers/scoped_ptr_hash_map.h"
	#include "base/metrics/histogram.h"
	#include "base/trace_event/trace_event.h"
	#include "cc/base/math_util.h"
	#include "cc/output/copy_output_request.h"
	#include "cc/quads/draw_quad.h"
	#include "ui/gfx/geometry/rect_conversions.h"
	#include "ui/gfx/transform.h"

	static gfx::Transform OrthoProjectionMatrix(float left,
	float right,
	float bottom,
	float top) {
	// Use the standard formula to map the clipping frustum to the cube from
	// [-1, -1, -1] to [1, 1, 1].
	float delta_x = right - left;
	float delta_y = top - bottom;
	gfx::Transform proj;
	if (!delta_x \|\| !delta_y)
	return proj;
	proj.matrix().set(0, 0, 2.0f / delta_x);
	proj.matrix().set(0, 3, -(right + left) / delta_x);
	proj.matrix().set(1, 1, 2.0f / delta_y);
	proj.matrix().set(1, 3, -(top + bottom) / delta_y);

	// Z component of vertices is always set to zero as we don't use the depth
	// buffer while drawing.
	proj.matrix().set(2, 2, 0);

	return proj;
	}

	static gfx::Transform window_matrix(int x, int y, int width, int height) {
	gfx::Transform canvas;

	// Map to window position and scale up to pixel coordinates.
	canvas.Translate3d(x, y, 0);
	canvas.Scale3d(width, height, 0);

	// Map from ([-1, -1] to [1, 1]) -> ([0, 0] to [1, 1])
	canvas.Translate3d(0.5, 0.5, 0.5);
	canvas.Scale3d(0.5, 0.5, 0.5);

	return canvas;
	}

	namespace cc {

	DirectRenderer::DrawingFrame::DrawingFrame()
	: root_render_pass(NULL), current_render_pass(NULL), current_texture(NULL) {
	}

	DirectRenderer::DrawingFrame::~DrawingFrame() {}

	//
	// static
	gfx::RectF DirectRenderer::QuadVertexRect() {
	return gfx::RectF(-0.5f, -0.5f, 1.f, 1.f);
	}

	// static
	void DirectRenderer::QuadRectTransform(gfx::Transform* quad_rect_transform,
	const gfx::Transform& quad_transform,
	const gfx::RectF& quad_rect) {
	*quad_rect_transform = quad_transform;
	quad_rect_transform->Translate(0.5 * quad_rect.width() + quad_rect.x(),
	0.5 * quad_rect.height() + quad_rect.y());
	quad_rect_transform->Scale(quad_rect.width(), quad_rect.height());
	}

	void DirectRenderer::InitializeViewport(DrawingFrame* frame,
	const gfx::Rect& draw_rect,
	const gfx::Rect& viewport_rect,
	const gfx::Size& surface_size) {
	DCHECK_GE(viewport_rect.x(), 0);
	DCHECK_GE(viewport_rect.y(), 0);
	DCHECK_LE(viewport_rect.right(), surface_size.width());
	DCHECK_LE(viewport_rect.bottom(), surface_size.height());
	bool flip_y = FlippedFramebuffer(frame);
	if (flip_y) {
	frame->projection_matrix = OrthoProjectionMatrix(draw_rect.x(),
	draw_rect.right(),
	draw_rect.bottom(),
	draw_rect.y());
	} else {
	frame->projection_matrix = OrthoProjectionMatrix(draw_rect.x(),
	draw_rect.right(),
	draw_rect.y(),
	draw_rect.bottom());
	}

	gfx::Rect window_rect = viewport_rect;
	if (flip_y)
	window_rect.set_y(surface_size.height() - viewport_rect.bottom());
	frame->window_matrix = window_matrix(window_rect.x(),
	window_rect.y(),
	window_rect.width(),
	window_rect.height());
	SetDrawViewport(window_rect);

	current_draw_rect_ = draw_rect;
	current_viewport_rect_ = viewport_rect;
	current_surface_size_ = surface_size;
	}

	gfx::Rect DirectRenderer::MoveFromDrawToWindowSpace(
	const DrawingFrame* frame,
	const gfx::Rect& draw_rect) const {
	gfx::Rect window_rect = draw_rect;
	window_rect -= current_draw_rect_.OffsetFromOrigin();
	window_rect += current_viewport_rect_.OffsetFromOrigin();
	if (FlippedFramebuffer(frame))
	window_rect.set_y(current_surface_size_.height() - window_rect.bottom());
	return window_rect;
	}

	DirectRenderer::DirectRenderer(RendererClient* client,
	const RendererSettings* settings,
	OutputSurface* output_surface,
	ResourceProvider* resource_provider)
	: Renderer(client, settings),
	output_surface_(output_surface),
	resource_provider_(resource_provider),
	overlay_processor_(
	new OverlayProcessor(output_surface, resource_provider)) {
	overlay_processor_->Initialize();
	}

	DirectRenderer::~DirectRenderer() {}

	void DirectRenderer::SetEnlargePassTextureAmountForTesting(
	const gfx::Vector2d& amount) {
	enlarge_pass_texture_amount_ = amount;
	}

	void DirectRenderer::DecideRenderPassAllocationsForFrame(
	const RenderPassList& render_passes_in_draw_order) {
	if (!resource_provider_)
	return;

	base::hash_map<RenderPassId, gfx::Size> render_passes_in_frame;
	for (size_t i = 0; i < render_passes_in_draw_order.size(); ++i)
	render_passes_in_frame.insert(std::pair<RenderPassId, gfx::Size>(
	render_passes_in_draw_order[i]->id,
	RenderPassTextureSize(render_passes_in_draw_order[i])));

	std::vector<RenderPassId> passes_to_delete;
	base::ScopedPtrHashMap<RenderPassId, ScopedResource>::const_iterator
	pass_iter;
	for (pass_iter = render_pass_textures_.begin();
	pass_iter != render_pass_textures_.end();
	++pass_iter) {
	base::hash_map<RenderPassId, gfx::Size>::const_iterator it =
	render_passes_in_frame.find(pass_iter->first);
	if (it == render_passes_in_frame.end()) {
	passes_to_delete.push_back(pass_iter->first);
	continue;
	}

	gfx::Size required_size = it->second;
	ScopedResource* texture = pass_iter->second;
	DCHECK(texture);

	bool size_appropriate = texture->size().width() >= required_size.width() &&
	texture->size().height() >= required_size.height();
	if (texture->id() && !size_appropriate)
	texture->Free();
	}

	// Delete RenderPass textures from the previous frame that will not be used
	// again.
	for (size_t i = 0; i < passes_to_delete.size(); ++i)
	render_pass_textures_.erase(passes_to_delete[i]);

	for (size_t i = 0; i < render_passes_in_draw_order.size(); ++i) {
	if (!render_pass_textures_.contains(render_passes_in_draw_order[i]->id)) {
	scoped_ptr<ScopedResource> texture =
	ScopedResource::Create(resource_provider_);
	render_pass_textures_.set(render_passes_in_draw_order[i]->id,
	texture.Pass());
	}
	}
	}

	void DirectRenderer::DrawFrame(RenderPassList* render_passes_in_draw_order,
	float device_scale_factor,
	const gfx::Rect& device_viewport_rect,
	const gfx::Rect& device_clip_rect,
	bool disable_picture_quad_image_filtering) {
	TRACE_EVENT0("cc", "DirectRenderer::DrawFrame");
	UMA_HISTOGRAM_COUNTS("Renderer4.renderPassCount",
	render_passes_in_draw_order->size());

	const RenderPass* root_render_pass = render_passes_in_draw_order->back();
	DCHECK(root_render_pass);

	DrawingFrame frame;
	frame.render_passes_in_draw_order = render_passes_in_draw_order;
	frame.root_render_pass = root_render_pass;
	frame.root_damage_rect = Capabilities().using_partial_swap
	? root_render_pass->damage_rect
	: root_render_pass->output_rect;
	frame.root_damage_rect.Intersect(gfx::Rect(device_viewport_rect.size()));
	frame.device_viewport_rect = device_viewport_rect;
	frame.device_clip_rect = device_clip_rect;
	frame.disable_picture_quad_image_filtering =
	disable_picture_quad_image_filtering;

	overlay_processor_->ProcessForOverlays(render_passes_in_draw_order,
	&frame.overlay_list);

	EnsureBackbuffer();

	// Only reshape when we know we are going to draw. Otherwise, the reshape
	// can leave the window at the wrong size if we never draw and the proper
	// viewport size is never set.
	output_surface_->Reshape(device_viewport_rect.size(), device_scale_factor);

	BeginDrawingFrame(&frame);
	for (size_t i = 0; i < render_passes_in_draw_order->size(); ++i) {
	RenderPass* pass = render_passes_in_draw_order->at(i);
	DrawRenderPass(&frame, pass);

	for (ScopedPtrVector<CopyOutputRequest>::iterator it =
	pass->copy_requests.begin();
	it != pass->copy_requests.end();
	++it) {
	if (i > 0) {
	// Doing a readback is destructive of our state on Mac, so make sure
	// we restore the state between readbacks. http://crbug.com/99393.
	UseRenderPass(&frame, pass);
	}
	CopyCurrentRenderPassToBitmap(&frame, pass->copy_requests.take(it));
	}
	}
	FinishDrawingFrame(&frame);

	render_passes_in_draw_order->clear();
	}

	gfx::Rect DirectRenderer::ComputeScissorRectForRenderPass(
	const DrawingFrame* frame) {
	gfx::Rect render_pass_scissor = frame->current_render_pass->output_rect;

	if (frame->root_damage_rect == frame->root_render_pass->output_rect \|\|
	!frame->current_render_pass->copy_requests.empty())
	return render_pass_scissor;

	gfx::Transform inverse_transform(gfx::Transform::kSkipInitialization);
	if (frame->current_render_pass->transform_to_root_target.GetInverse(
	&inverse_transform)) {
	// Only intersect inverse-projected damage if the transform is invertible.
	gfx::Rect damage_rect_in_render_pass_space =
	MathUtil::ProjectEnclosingClippedRect(inverse_transform,
	frame->root_damage_rect);
	render_pass_scissor.Intersect(damage_rect_in_render_pass_space);
	}

	return render_pass_scissor;
	}

	bool DirectRenderer::NeedDeviceClip(const DrawingFrame* frame) const {
	if (frame->current_render_pass != frame->root_render_pass)
	return false;

	return !frame->device_clip_rect.Contains(frame->device_viewport_rect);
	}

	gfx::Rect DirectRenderer::DeviceClipRectInWindowSpace(const DrawingFrame* frame)
	const {
	gfx::Rect device_clip_rect = frame->device_clip_rect;
	if (FlippedFramebuffer(frame))
	device_clip_rect.set_y(current_surface_size_.height() -
	device_clip_rect.bottom());
	return device_clip_rect;
	}

	void DirectRenderer::SetScissorStateForQuad(const DrawingFrame* frame,
	const DrawQuad& quad) {
	if (quad.isClipped()) {
	SetScissorTestRectInDrawSpace(frame, quad.clipRect());
	return;
	}
	if (NeedDeviceClip(frame)) {
	SetScissorTestRect(DeviceClipRectInWindowSpace(frame));
	return;
	}

	EnsureScissorTestDisabled();
	}

	void DirectRenderer::SetScissorStateForQuadWithRenderPassScissor(
	const DrawingFrame* frame,
	const DrawQuad& quad,
	const gfx::Rect& render_pass_scissor,
	bool* should_skip_quad) {
	gfx::Rect quad_scissor_rect = render_pass_scissor;

	if (quad.isClipped())
	quad_scissor_rect.Intersect(quad.clipRect());

	if (quad_scissor_rect.IsEmpty()) {
	*should_skip_quad = true;
	return;
	}

	*should_skip_quad = false;
	SetScissorTestRectInDrawSpace(frame, quad_scissor_rect);
	}

	void DirectRenderer::SetScissorTestRectInDrawSpace(
	const DrawingFrame* frame,
	const gfx::Rect& draw_space_rect) {
	gfx::Rect window_space_rect =
	MoveFromDrawToWindowSpace(frame, draw_space_rect);
	if (NeedDeviceClip(frame))
	window_space_rect.Intersect(DeviceClipRectInWindowSpace(frame));
	SetScissorTestRect(window_space_rect);
	}

	void DirectRenderer::FinishDrawingQuadList() {}

	void DirectRenderer::DrawRenderPass(DrawingFrame* frame,
	const RenderPass* render_pass) {
	TRACE_EVENT0("cc", "DirectRenderer::DrawRenderPass");
	if (!UseRenderPass(frame, render_pass))
	return;

	bool using_scissor_as_optimization = Capabilities().using_partial_swap;
	gfx::Rect render_pass_scissor;
	bool draw_rect_covers_full_surface = true;
	if (frame->current_render_pass == frame->root_render_pass &&
	!frame->device_viewport_rect.Contains(
	gfx::Rect(output_surface_->SurfaceSize())))
	draw_rect_covers_full_surface = false;

	if (using_scissor_as_optimization) {
	render_pass_scissor = ComputeScissorRectForRenderPass(frame);
	SetScissorTestRectInDrawSpace(frame, render_pass_scissor);
	if (!render_pass_scissor.Contains(frame->current_render_pass->output_rect))
	draw_rect_covers_full_surface = false;
	}

	if (frame->current_render_pass != frame->root_render_pass \|\|
	settings_->should_clear_root_render_pass) {
	if (NeedDeviceClip(frame)) {
	SetScissorTestRect(DeviceClipRectInWindowSpace(frame));
	draw_rect_covers_full_surface = false;
	} else if (!using_scissor_as_optimization) {
	EnsureScissorTestDisabled();
	}

	bool has_external_stencil_test =
	output_surface_->HasExternalStencilTest() &&
	frame->current_render_pass == frame->root_render_pass;

	DiscardPixels(has_external_stencil_test, draw_rect_covers_full_surface);
	ClearFramebuffer(frame, has_external_stencil_test);
	}

	const QuadList& quad_list = render_pass->quad_list;
	for (auto it = quad_list.BackToFrontBegin(); it != quad_list.BackToFrontEnd();
	++it) {
	const DrawQuad& quad = **it;
	bool should_skip_quad = false;

	if (using_scissor_as_optimization) {
	SetScissorStateForQuadWithRenderPassScissor(
	frame, quad, render_pass_scissor, &should_skip_quad);
	} else {
	SetScissorStateForQuad(frame, quad);
	}

	if (!should_skip_quad)
	DoDrawQuad(frame, &quad);
	}
	FinishDrawingQuadList();
	}

	bool DirectRenderer::UseRenderPass(DrawingFrame* frame,
	const RenderPass* render_pass) {
	frame->current_render_pass = render_pass;
	frame->current_texture = NULL;

	if (render_pass == frame->root_render_pass) {
	BindFramebufferToOutputSurface(frame);
	InitializeViewport(frame,
	render_pass->output_rect,
	frame->device_viewport_rect,
	output_surface_->SurfaceSize());
	return true;
	}

	ScopedResource* texture = render_pass_textures_.get(render_pass->id);
	DCHECK(texture);

	gfx::Size size = RenderPassTextureSize(render_pass);
	size.Enlarge(enlarge_pass_texture_amount_.x(),
	enlarge_pass_texture_amount_.y());
	if (!texture->id())
	texture->Allocate(
	size, ResourceProvider::TextureHintImmutableFramebuffer, RGBA_8888);
	DCHECK(texture->id());

	return BindFramebufferToTexture(frame, texture, render_pass->output_rect);
	}

	bool DirectRenderer::HasAllocatedResourcesForTesting(RenderPassId id) const {
	ScopedResource* texture = render_pass_textures_.get(id);
	return texture && texture->id();
	}

	// static
	gfx::Size DirectRenderer::RenderPassTextureSize(const RenderPass* render_pass) {
	return render_pass->output_rect.size();
	}

	} // namespace cc