/*
 * Copyright (c) 2010, Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"

#include "DrawingBuffer.h"

#include "Extensions3DChromium.h"
#include "GraphicsContext3D.h"
#include "SharedGraphicsContext3D.h"

#if ENABLE(SKIA_GPU)
#include "GrContext.h"
#endif

#if USE(ACCELERATED_COMPOSITING)
#include "Canvas2DLayerChromium.h"
#endif

namespace WebCore {

struct DrawingBufferInternal {
    unsigned offscreenColorTexture;
#if USE(ACCELERATED_COMPOSITING)
    RefPtr<Canvas2DLayerChromium> platformLayer;
#endif
};

static unsigned generateColorTexture(GraphicsContext3D* context, const IntSize& size)
{
    unsigned offscreenColorTexture = context->createTexture();
    if (!offscreenColorTexture)
        return 0;

    context->bindTexture(GraphicsContext3D::TEXTURE_2D, offscreenColorTexture);
    context->texParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_MAG_FILTER, GraphicsContext3D::NEAREST);
    context->texParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_MIN_FILTER, GraphicsContext3D::NEAREST);
    context->texParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_WRAP_S, GraphicsContext3D::CLAMP_TO_EDGE);
    context->texParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_WRAP_T, GraphicsContext3D::CLAMP_TO_EDGE);
    context->texImage2DResourceSafe(GraphicsContext3D::TEXTURE_2D, 0, GraphicsContext3D::RGBA, size.width(), size.height(), 0, GraphicsContext3D::RGBA, GraphicsContext3D::UNSIGNED_BYTE);
    context->framebufferTexture2D(GraphicsContext3D::FRAMEBUFFER, GraphicsContext3D::COLOR_ATTACHMENT0, GraphicsContext3D::TEXTURE_2D, offscreenColorTexture, 0);

    return offscreenColorTexture;
}


DrawingBuffer::DrawingBuffer(GraphicsContext3D* context,
                             const IntSize& size,
                             bool multisampleExtensionSupported,
                             bool packedDepthStencilExtensionSupported)
    : m_context(context)
    , m_size(-1, -1)
    , m_multisampleExtensionSupported(multisampleExtensionSupported)
    , m_packedDepthStencilExtensionSupported(packedDepthStencilExtensionSupported)
    , m_fbo(0)
    , m_colorBuffer(0)
    , m_depthStencilBuffer(0)
    , m_depthBuffer(0)
    , m_stencilBuffer(0)
    , m_multisampleFBO(0)
    , m_multisampleColorBuffer(0)
    , m_internal(new DrawingBufferInternal)
#if ENABLE(SKIA_GPU)
    , m_grContext(0)
#endif
{
    if (!m_context->getExtensions()->supports("GL_CHROMIUM_copy_texture_to_parent_texture")) {
        m_context.clear();
        return;
    }
    m_fbo = context->createFramebuffer();
    context->bindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_fbo);
    m_colorBuffer = generateColorTexture(context, size);
    createSecondaryBuffers();
    reset(size);
}

DrawingBuffer::~DrawingBuffer()
{
#if USE(ACCELERATED_COMPOSITING)
    if (m_internal->platformLayer)
        m_internal->platformLayer->setDrawingBuffer(0);
#endif

    if (!m_context)
        return;
        
    m_context->bindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_fbo);
    m_context->deleteTexture(m_colorBuffer);

    clear();
}

#if USE(ACCELERATED_COMPOSITING)
void DrawingBuffer::publishToPlatformLayer()
{
    if (!m_context)
        return;
        
    if (m_callback)
        m_callback->willPublish();
    if (multisample())
        commit();
    unsigned parentTexture = m_internal->platformLayer->textureId();
    // FIXME: We do the copy in the canvas' (child) context so that it executes in the correct order relative to
    // other commands in the child context.  This ensures that the parent texture always contains a complete
    // frame and not some intermediate result.  However, there is no synchronization to ensure that this copy
    // happens before the compositor draws.  This means we might draw stale frames sometimes.  Ideally this
    // would insert a fence into the child command stream that the compositor could wait for.
    m_context->makeContextCurrent();
#if ENABLE(SKIA_GPU)
    if (m_grContext)
        m_grContext->flush(0);
#endif
    static_cast<Extensions3DChromium*>(m_context->getExtensions())->copyTextureToParentTextureCHROMIUM(m_colorBuffer, parentTexture);
    m_context->flush();
}
#endif

void DrawingBuffer::didReset()
{
#if USE(ACCELERATED_COMPOSITING)
    if (m_internal->platformLayer)
        m_internal->platformLayer->setTextureChanged();
#endif
}

#if USE(ACCELERATED_COMPOSITING)
PlatformLayer* DrawingBuffer::platformLayer()
{
    if (!m_internal->platformLayer)
        m_internal->platformLayer = Canvas2DLayerChromium::create(this, 0);
    return m_internal->platformLayer.get();
}
#endif

Platform3DObject DrawingBuffer::platformColorBuffer() const
{
    return m_colorBuffer;
}

#if ENABLE(SKIA_GPU)
void DrawingBuffer::setGrContext(GrContext* context)
{
    // We just take a ptr without referencing it, as we require that we never outlive
    // the SharedGraphicsContext3D object that is giving us the context.
    m_grContext = context;
}

void DrawingBuffer::getGrPlatformSurfaceDesc(GrPlatformSurfaceDesc* desc)
{
    desc->fSurfaceType = kTextureRenderTarget_GrPlatformSurfaceType;

    desc->fPlatformTexture = m_colorBuffer;
    if (multisample()) {
        desc->fRenderTargetFlags = kIsMultisampled_GrPlatformRenderTargetFlagBit | kGrCanResolve_GrPlatformRenderTargetFlagBit;
        desc->fPlatformRenderTarget = m_multisampleFBO;
        desc->fPlatformResolveDestination = m_fbo;
    } else {
        desc->fRenderTargetFlags = kNone_GrPlatformRenderTargetFlagBit;
        desc->fPlatformRenderTarget = m_fbo;
        desc->fPlatformResolveDestination = 0;
    }

    desc->fWidth = m_size.width();
    desc->fHeight = m_size.height();
    desc->fConfig = kRGBA_8888_GrPixelConfig;

    desc->fStencilBits = (m_depthStencilBuffer || m_stencilBuffer) ? 8 : 0;
}

#endif

}