third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp

// Copyright 2016 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 "platform/graphics/OffscreenCanvasFrameDispatcherImpl.h"

#include "cc/output/compositor_frame.h"
#include "cc/output/delegated_frame_data.h"
#include "cc/quads/render_pass.h"
#include "cc/quads/shared_quad_state.h"
#include "cc/quads/solid_color_draw_quad.h"
#include "cc/quads/texture_draw_quad.h"
#include "cc/resources/returned_resource.h"
#include "public/platform/InterfaceProvider.h"
#include "public/platform/Platform.h"
#include "public/platform/modules/offscreencanvas/offscreen_canvas_surface.mojom-blink.h"
#include "third_party/khronos/GLES2/gl2.h"
#include "third_party/skia/include/core/SkColor.h"
#include "third_party/skia/include/core/SkXfermode.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/transform.h"

namespace blink {

OffscreenCanvasFrameDispatcherImpl::OffscreenCanvasFrameDispatcherImpl(uint32_t clientId, uint32_t localId, uint64_t nonce, int width, int height)
    : m_surfaceId(cc::SurfaceId(clientId, localId, nonce))
    , m_width(width)
    , m_height(height)
    , m_binding(this)
{
    DCHECK(!m_sink.is_bound());
    mojom::blink::OffscreenCanvasCompositorFrameSinkProviderPtr provider;
    Platform::current()->interfaceProvider()->getInterface(mojo::GetProxy(&provider));
    provider->CreateCompositorFrameSink(m_surfaceId, m_binding.CreateInterfacePtrAndBind(), mojo::GetProxy(&m_sink));
}

void OffscreenCanvasFrameDispatcherImpl::dispatchFrame(RefPtr<StaticBitmapImage> image)
{
    cc::CompositorFrame frame;
    frame.metadata.device_scale_factor = 1.0f;
    frame.delegated_frame_data.reset(new cc::DelegatedFrameData);

    const gfx::Rect bounds(m_width, m_height);
    const cc::RenderPassId renderPassId(1, 1);
    std::unique_ptr<cc::RenderPass> pass = cc::RenderPass::Create();
    pass->SetAll(renderPassId, bounds, bounds, gfx::Transform(), false);

    cc::SharedQuadState* sqs = pass->CreateAndAppendSharedQuadState();
    sqs->SetAll(gfx::Transform(), bounds.size(), bounds, bounds, false, 1.f, SkXfermode::kSrcOver_Mode, 0);

    unsigned nextResourceId = 1u;
    // TODO(xidachen): for now, we just submit a SolidColor frame to compositor in the 2d case,
    // we should extract data from image.
    if (!image) {
        cc::SolidColorDrawQuad* quad = pass->CreateAndAppendDrawQuad<cc::SolidColorDrawQuad>();
        const bool forceAntialiasingOff = false;
        quad->SetNew(sqs, bounds, bounds, SK_ColorGREEN, forceAntialiasingOff);
    } else { // WebGL
        DCHECK(image->isTextureBacked());
        cc::TransferableResource resource;
        resource.id = nextResourceId;
        resource.format = cc::ResourceFormat::RGBA_8888;
        // TODO(crbug.com/645590): filter should respect the image-rendering CSS property of associated canvas element.
        resource.filter = GL_LINEAR;
        resource.size = gfx::Size(m_width, m_height);
        image->ensureMailbox();
        resource.mailbox_holder = gpu::MailboxHolder(image->getMailbox(), image->getSyncToken(), GL_TEXTURE_2D);
        resource.read_lock_fences_enabled = false;
        resource.is_software = false;
        // TODO(crbug.com/646022): making this overlay-able.
        resource.is_overlay_candidate = false;
        frame.delegated_frame_data->resource_list.push_back(std::move(resource));

        // Hold ref to |image|, to keep it alive until the browser ReturnResources.
        // It guarantees that the resource is not re-used or deleted.
        m_cachedImages.add(nextResourceId++, std::move(image));

        cc::TextureDrawQuad* quad = pass->CreateAndAppendDrawQuad<cc::TextureDrawQuad>();
        gfx::Size rectSize(m_width, m_height);

        const bool needsBlending = true;
        // TOOD(crbug.com/645993): this should be inherited from WebGL context's creation settings.
        const bool premultipliedAlpha = true;
        const gfx::PointF uvTopLeft(0.f, 0.f);
        const gfx::PointF uvBottomRight(1.f, 1.f);
        float vertexOpacity[4] = { 1.f, 1.f, 1.f, 1.f };
        const bool yflipped = false;
        // TODO(crbug.com/645994): this should be true when using style "image-rendering: pixelated".
        const bool nearestNeighbor = false;
        quad->SetAll(sqs, bounds, bounds, bounds, needsBlending, resource.id, gfx::Size(), premultipliedAlpha,
            uvTopLeft, uvBottomRight, SK_ColorTRANSPARENT, vertexOpacity, yflipped, nearestNeighbor, false);
    }

    frame.delegated_frame_data->render_pass_list.push_back(std::move(pass));

    m_sink->SubmitCompositorFrame(std::move(frame), base::Closure());
}

void OffscreenCanvasFrameDispatcherImpl::ReturnResources(Vector<cc::mojom::blink::ReturnedResourcePtr> resources)
{
    for (const auto& resource : resources)
        m_cachedImages.remove(resource->id);
}

} // namespace blink