WebGLLayerChromium.cpp   [plain text]

/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
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 * 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
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 *     * 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.
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 * 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
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 */

#include "config.h"

#if USE(ACCELERATED_COMPOSITING)

#include "WebGLLayerChromium.h"

#include "Extensions3DChromium.h"
#include "GraphicsContext3D.h"
#include "LayerRendererChromium.h"
#include "TraceEvent.h"

namespace WebCore {

PassRefPtr<WebGLLayerChromium> WebGLLayerChromium::create(GraphicsLayerChromium* owner)
{
    return adoptRef(new WebGLLayerChromium(owner));
}

WebGLLayerChromium::WebGLLayerChromium(GraphicsLayerChromium* owner)
    : CanvasLayerChromium(owner)
    , m_context(0)
    , m_contextSupportsRateLimitingExtension(false)
    , m_rateLimitingTimer(this, &WebGLLayerChromium::rateLimitContext)
    , m_textureUpdated(false)
{
}

WebGLLayerChromium::~WebGLLayerChromium()
{
    if (m_context && layerRenderer())
        layerRenderer()->removeChildContext(m_context);
}

void WebGLLayerChromium::updateCompositorResources()
{
    if (!m_context)
        return;

    if (!m_contentsDirty)
        return;

    GraphicsContext3D* rendererContext = layerRendererContext();
    if (m_textureChanged) {
        rendererContext->bindTexture(GraphicsContext3D::TEXTURE_2D, m_textureId);
        // Set the min-mag filters to linear and wrap modes to GL_CLAMP_TO_EDGE
        // to get around NPOT texture limitations of GLES.
        rendererContext->texParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_MIN_FILTER, GraphicsContext3D::LINEAR);
        rendererContext->texParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_MAG_FILTER, GraphicsContext3D::LINEAR);
        rendererContext->texParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_WRAP_S, GraphicsContext3D::CLAMP_TO_EDGE);
        rendererContext->texParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_WRAP_T, GraphicsContext3D::CLAMP_TO_EDGE);
        m_textureChanged = false;
    }
    // Update the contents of the texture used by the compositor.
    if (m_contentsDirty && m_textureUpdated) {
        // prepareTexture copies the contents of the off-screen render target into the texture
        // used by the compositor.
        //
        m_context->prepareTexture();
        m_context->markLayerComposited();
        m_contentsDirty = false;
        m_textureUpdated = false;
    }
}

void WebGLLayerChromium::setTextureUpdated()
{
    m_textureUpdated = true;
    // If WebGL commands are issued outside of a the animation callbacks, then use
    // call rateLimitOffscreenContextCHROMIUM() to keep the context from getting too far ahead.
    if (layerRenderer() && !layerRenderer()->isAnimating() && m_contextSupportsRateLimitingExtension && !m_rateLimitingTimer.isActive())
        m_rateLimitingTimer.startOneShot(0);
}

void WebGLLayerChromium::setContext(const GraphicsContext3D* context)
{
    if (m_context != context && layerRenderer()) {
        if (m_context)
            layerRenderer()->removeChildContext(m_context);
        if (context)
            layerRenderer()->addChildContext(const_cast<GraphicsContext3D*>(context));
    }

    m_context = const_cast<GraphicsContext3D*>(context);

    if (!m_context)
        return;

    unsigned int textureId = m_context->platformTexture();
    if (textureId != m_textureId) {
        m_textureChanged = true;
        m_textureUpdated = true;
    }
    m_textureId = textureId;
    m_premultipliedAlpha = m_context->getContextAttributes().premultipliedAlpha;
    m_contextSupportsRateLimitingExtension = m_context->getExtensions()->supports("GL_CHROMIUM_rate_limit_offscreen_context");
}

void WebGLLayerChromium::setLayerRenderer(LayerRendererChromium* newLayerRenderer)
{
    if (layerRenderer() != newLayerRenderer) {
        if (m_context) {
            if (layerRenderer())
                layerRenderer()->removeChildContext(m_context);
            if (newLayerRenderer)
                newLayerRenderer->addChildContext(m_context);
        }

        LayerChromium::setLayerRenderer(newLayerRenderer);
    }
}

void WebGLLayerChromium::rateLimitContext(Timer<WebGLLayerChromium>*)
{
    TRACE_EVENT("WebGLLayerChromium::rateLimitContext", this, 0);

    if (!m_context)
        return;

    Extensions3DChromium* extensions = static_cast<Extensions3DChromium*>(m_context->getExtensions());
    extensions->rateLimitOffscreenContextCHROMIUM();
}

}
#endif // USE(ACCELERATED_COMPOSITING)