WebGL: Transfer ownership of WebGraphicsContext3D from WebGLRenderingContext to DrawingBuffer.

Source/platform/graphics/gpu/DrawingBuffer.cpp

 /*
  * 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
@@ skipping 59 matching lines @@
         m_context->bindTexture(GL_TEXTURE_2D, m_oldTextureUnitZeroId);
         m_context->activeTexture(m_oldActiveTextureUnit);
     }
 
 private:
     blink::WebGraphicsContext3D* m_context;
     GLenum m_oldActiveTextureUnit;
     Platform3DObject m_oldTextureUnitZeroId;
 };
 
-PassRefPtr<DrawingBuffer> DrawingBuffer::create(blink::WebGraphicsContext3D* context, const IntSize& size, PreserveDrawingBuffer preserve, PassRefPtr<ContextEvictionManager> contextEvictionManager)
+PassRefPtr<DrawingBuffer> DrawingBuffer::create(PassOwnPtr<blink::WebGraphicsContext3D> context, const IntSize& size, PreserveDrawingBuffer preserve, PassRefPtr<ContextEvictionManager> contextEvictionManager)
 {
-    Extensions3DUtil extensionsUtil(context);
+    ASSERT(context);
+    Extensions3DUtil extensionsUtil(context.get());
     bool multisampleSupported = extensionsUtil.supportsExtension("GL_CHROMIUM_framebuffer_multisample")
         && extensionsUtil.supportsExtension("GL_OES_rgb8_rgba8");
     if (multisampleSupported) {
         extensionsUtil.ensureExtensionEnabled("GL_CHROMIUM_framebuffer_multisample");
         extensionsUtil.ensureExtensionEnabled("GL_OES_rgb8_rgba8");
     }
     bool packedDepthStencilSupported = extensionsUtil.supportsExtension("GL_OES_packed_depth_stencil");
     if (packedDepthStencilSupported)
         extensionsUtil.ensureExtensionEnabled("GL_OES_packed_depth_stencil");
 
-    RefPtr<DrawingBuffer> drawingBuffer = adoptRef(new DrawingBuffer(context, size, multisampleSupported, packedDepthStencilSupported, preserve, contextEvictionManager));
+    RefPtr<DrawingBuffer> drawingBuffer = adoptRef(new DrawingBuffer(context, multisampleSupported, packedDepthStencilSupported, preserve, contextEvictionManager));
+    if (!drawingBuffer->initialize(size))
+        return PassRefPtr<DrawingBuffer>();
     return drawingBuffer.release();
 }
 
-DrawingBuffer::DrawingBuffer(blink::WebGraphicsContext3D* context,
-    const IntSize& size,
+DrawingBuffer::DrawingBuffer(PassOwnPtr<blink::WebGraphicsContext3D> context,
     bool multisampleExtensionSupported,
     bool packedDepthStencilExtensionSupported,
     PreserveDrawingBuffer preserve,
     PassRefPtr<ContextEvictionManager> contextEvictionManager)
     : m_preserveDrawingBuffer(preserve)
     , m_scissorEnabled(false)
     , m_texture2DBinding(0)
     , m_framebufferBinding(0)
     , m_activeTextureUnit(GL_TEXTURE0)
     , m_context(context)
     , m_size(-1, -1)
     , m_multisampleExtensionSupported(multisampleExtensionSupported)
     , m_packedDepthStencilExtensionSupported(packedDepthStencilExtensionSupported)
     , m_fbo(0)
     , m_colorBuffer(0)
     , m_frontColorBuffer(0)
     , m_depthStencilBuffer(0)
     , m_depthBuffer(0)
     , m_stencilBuffer(0)
     , m_multisampleFBO(0)
     , m_multisampleColorBuffer(0)
     , m_contentsChanged(true)
     , m_contentsChangeCommitted(false)
     , m_layerComposited(false)
     , m_internalColorFormat(0)
     , m_colorFormat(0)
     , m_internalRenderbufferFormat(0)
     , m_maxTextureSize(0)
+    , m_sampleCount(4)
     , m_packAlignment(4)
     , m_contextEvictionManager(contextEvictionManager)
 {
     // Used by browser tests to detect the use of a DrawingBuffer.
     TRACE_EVENT_INSTANT0("test_gpu", "DrawingBufferCreation");
-    initialize(size);
 }
 
 DrawingBuffer::~DrawingBuffer()
 {
     releaseResources();
 }
 
 void DrawingBuffer::markContentsChanged()
 {
     m_contentsChanged = true;
     m_contentsChangeCommitted = false;
     m_layerComposited = false;
 }
 
 bool DrawingBuffer::layerComposited() const
 {
     return m_layerComposited;
 }
 
 void DrawingBuffer::markLayerComposited()
 {
     m_layerComposited = true;
 }
 
 blink::WebGraphicsContext3D* DrawingBuffer::context()
 {
-    return m_context;
+    return m_context.get();
 }
 
 bool DrawingBuffer::prepareMailbox(blink::WebExternalTextureMailbox* outMailbox, blink::WebExternalBitmap* bitmap)
 {
-    if (!m_context || !m_contentsChanged)
+    if (!m_contentsChanged)
         return false;
 
     m_context->makeContextCurrent();
 
     // Resolve the multisampled buffer into m_colorBuffer texture.
     if (multisample())
         commit();
 
     if (bitmap) {
         bitmap->setSize(size());
 
         unsigned char* pixels = bitmap->pixels();
         bool needPremultiply = m_attributes.alpha && !m_attributes.premultipliedAlpha;
         WebGLImageConversion::AlphaOp op = needPremultiply ? WebGLImageConversion::AlphaDoPremultiply : WebGLImageConversion::AlphaDoNothing;
         if (pixels)
             readBackFramebuffer(pixels, size().width(), size().height(), ReadbackSkia, op);
     }
 
     // We must restore the texture binding since creating new textures,
     // consuming and producing mailboxes changes it.
-    ScopedTextureUnit0BindingRestorer restorer(m_context, m_activeTextureUnit, m_texture2DBinding);
+    ScopedTextureUnit0BindingRestorer restorer(m_context.get(), m_activeTextureUnit, m_texture2DBinding);
 
     // First try to recycle an old buffer.
     RefPtr<MailboxInfo> frontColorBufferMailbox = recycledMailbox();
 
     // No buffer available to recycle, create a new one.
     if (!frontColorBufferMailbox) {
         unsigned newColorBuffer = createColorTexture(m_size);
         // Bad things happened, abandon ship.
         if (!newColorBuffer)
             return false;
@@ skipping 39 matching lines @@
             mailboxInfo->mailbox.syncPoint = mailbox.syncPoint;
             m_recycledMailboxes.prepend(mailboxInfo.release());
             return;
         }
     }
     ASSERT_NOT_REACHED();
 }
 
 PassRefPtr<DrawingBuffer::MailboxInfo> DrawingBuffer::recycledMailbox()
 {
-    if (!m_context || m_recycledMailboxes.isEmpty())
+    if (m_recycledMailboxes.isEmpty())
         return PassRefPtr<MailboxInfo>();
 
     RefPtr<MailboxInfo> mailboxInfo = m_recycledMailboxes.last().release();
     m_recycledMailboxes.removeLast();
 
     if (mailboxInfo->mailbox.syncPoint) {
         m_context->waitSyncPoint(mailboxInfo->mailbox.syncPoint);
         mailboxInfo->mailbox.syncPoint = 0;
     }
 
     if (mailboxInfo->size != m_size) {
         m_context->bindTexture(GL_TEXTURE_2D, mailboxInfo->textureId);
         texImage2DResourceSafe(GL_TEXTURE_2D, 0, m_internalColorFormat, m_size.width(), m_size.height(), 0, m_colorFormat, GL_UNSIGNED_BYTE);
         mailboxInfo->size = m_size;
     }
 
     return mailboxInfo.release();
 }
 
 PassRefPtr<DrawingBuffer::MailboxInfo> DrawingBuffer::createNewMailbox(unsigned textureId)
 {
     RefPtr<MailboxInfo> returnMailbox = adoptRef(new MailboxInfo());
     m_context->genMailboxCHROMIUM(returnMailbox->mailbox.name);
     returnMailbox->textureId = textureId;
     returnMailbox->size = m_size;
     m_textureMailboxes.append(returnMailbox);
     return returnMailbox.release();
 }
 
-void DrawingBuffer::initialize(const IntSize& size)
+bool DrawingBuffer::initialize(const IntSize& size)
 {
-    ASSERT(m_context);
     m_attributes = m_context->getContextAttributes();
 
     if (m_attributes.alpha) {
         m_internalColorFormat = GL_RGBA;
         m_colorFormat = GL_RGBA;
         m_internalRenderbufferFormat = GL_RGBA8_OES;
     } else {
         m_internalColorFormat = GL_RGB;
         m_colorFormat = GL_RGB;
         m_internalRenderbufferFormat = GL_RGB8_OES;
     }
 
     m_context->getIntegerv(GL_MAX_TEXTURE_SIZE, &m_maxTextureSize);
 
     int maxSampleCount = 0;
     if (multisample())
         m_context->getIntegerv(GL_MAX_SAMPLES_ANGLE, &maxSampleCount);
     m_sampleCount = std::min(4, maxSampleCount);
 
     m_fbo = m_context->createFramebuffer();
 
     m_context->bindFramebuffer(GL_FRAMEBUFFER, m_fbo);
     m_colorBuffer = createColorTexture();
     m_context->framebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_colorBuffer, 0);
     createSecondaryBuffers();
-    reset(size);
+    return reset(size);
 }
 
 bool DrawingBuffer::copyToPlatformTexture(blink::WebGraphicsContext3D* context, Platform3DObject texture, GLenum internalFormat, GLenum destType, GLint level, bool premultiplyAlpha, bool flipY)
 {
-    if (!m_context || !m_context->makeContextCurrent())
+    if (!m_context->makeContextCurrent())
         return false;
     if (m_contentsChanged) {
         if (multisample()) {
             commit();
             if (!m_framebufferBinding)
                 bind();
             else
                 restoreFramebufferBinding();
         }
         m_context->flush();
@@ skipping 25 matching lines @@
     return true;
 }
 
 Platform3DObject DrawingBuffer::framebuffer() const
 {
     return m_fbo;
 }
 
 blink::WebLayer* DrawingBuffer::platformLayer()
 {
-    if (!m_context)
-        return 0;
-
     if (!m_layer) {
         m_layer = adoptPtr(blink::Platform::current()->compositorSupport()->createExternalTextureLayer(this));
 
         m_layer->setOpaque(!m_attributes.alpha);
         m_layer->setBlendBackgroundColor(m_attributes.alpha);
         m_layer->setPremultipliedAlpha(m_attributes.premultipliedAlpha);
         GraphicsLayer::registerContentsLayer(m_layer->layer());
     }
 
     return m_layer->layer();
 }
 
 void DrawingBuffer::paintCompositedResultsToCanvas(ImageBuffer* imageBuffer)
 {
-    if (!m_context || !m_context->makeContextCurrent() || m_context->getGraphicsResetStatusARB() != GL_NO_ERROR)
+    if (!m_context->makeContextCurrent() || m_context->getGraphicsResetStatusARB() != GL_NO_ERROR)
         return;
 
     if (!imageBuffer)
         return;
     Platform3DObject tex = imageBuffer->getBackingTexture();
     if (tex) {
         m_context->copyTextureCHROMIUM(GL_TEXTURE_2D, m_frontColorBuffer,
             tex, 0, GL_RGBA, GL_UNSIGNED_BYTE);
         return;
     }
@@ skipping 20 matching lines @@
     m_context->deleteTexture(sourceTexture);
 
     m_context->bindFramebuffer(GL_FRAMEBUFFER, previousFramebuffer);
 }
 
 void DrawingBuffer::clearPlatformLayer()
 {
     if (m_layer)
         m_layer->clearTexture();
 
-    if (m_context)
-        m_context->flush();
+    m_context->flush();
 }
 
 void DrawingBuffer::releaseResources()
 {
-    if (m_context) {
-        m_context->makeContextCurrent();
+    m_context->makeContextCurrent();
 
-        clearPlatformLayer();
+    clearPlatformLayer();
 
-        for (size_t i = 0; i < m_textureMailboxes.size(); i++)
-            m_context->deleteTexture(m_textureMailboxes[i]->textureId);
+    for (size_t i = 0; i < m_textureMailboxes.size(); i++)
+        m_context->deleteTexture(m_textureMailboxes[i]->textureId);
 
-        if (m_multisampleColorBuffer)
-            m_context->deleteRenderbuffer(m_multisampleColorBuffer);
+    if (m_multisampleColorBuffer)
+        m_context->deleteRenderbuffer(m_multisampleColorBuffer);
 
-        if (m_depthStencilBuffer)
-            m_context->deleteRenderbuffer(m_depthStencilBuffer);
+    if (m_depthStencilBuffer)
+        m_context->deleteRenderbuffer(m_depthStencilBuffer);
 
-        if (m_depthBuffer)
-            m_context->deleteRenderbuffer(m_depthBuffer);
+    if (m_depthBuffer)
+        m_context->deleteRenderbuffer(m_depthBuffer);
 
-        if (m_stencilBuffer)
-            m_context->deleteRenderbuffer(m_stencilBuffer);
+    if (m_stencilBuffer)
+        m_context->deleteRenderbuffer(m_stencilBuffer);
 
-        if (m_multisampleFBO)
-            m_context->deleteFramebuffer(m_multisampleFBO);
+    if (m_multisampleFBO)
+        m_context->deleteFramebuffer(m_multisampleFBO);
 
-        if (m_fbo)
-            m_context->deleteFramebuffer(m_fbo);
+    if (m_fbo)
+        m_context->deleteFramebuffer(m_fbo);
 
-        m_context = 0;
-    }
+    m_context.clear();
 
     setSize(IntSize());
 
     m_colorBuffer = 0;
     m_frontColorBuffer = 0;
     m_multisampleColorBuffer = 0;
     m_depthStencilBuffer = 0;
     m_depthBuffer = 0;
     m_stencilBuffer = 0;
     m_multisampleFBO = 0;
     m_fbo = 0;
     m_contextEvictionManager.clear();
 
     m_recycledMailboxes.clear();
     m_textureMailboxes.clear();
 
     if (m_layer) {
         GraphicsLayer::unregisterContentsLayer(m_layer->layer());
         m_layer.clear();
     }
 }
 
 unsigned DrawingBuffer::createColorTexture(const IntSize& size)
 {
-    if (!m_context)
-        return 0;
-
     unsigned offscreenColorTexture = m_context->createTexture();
     if (!offscreenColorTexture)
         return 0;
 
     m_context->bindTexture(GL_TEXTURE_2D, offscreenColorTexture);
     m_context->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
     m_context->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
     m_context->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     m_context->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
     if (!size.isEmpty())
@@ skipping 87 matching lines @@
             m_context->framebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, m_stencilBuffer);
         }
     }
     m_context->bindRenderbuffer(GL_RENDERBUFFER, 0);
 }
 
 
 
 void DrawingBuffer::clearFramebuffers(GLbitfield clearMask)
 {
-    if (!m_context)
-        return;
-
     // We will clear the multisample FBO, but we also need to clear the non-multisampled buffer too.
     if (m_multisampleFBO) {
         m_context->bindFramebuffer(GL_FRAMEBUFFER, m_fbo);
         m_context->clear(GL_COLOR_BUFFER_BIT);
     }
 
     m_context->bindFramebuffer(GL_FRAMEBUFFER, m_multisampleFBO ? m_multisampleFBO : m_fbo);
     m_context->clear(clearMask);
 }
 
@@ skipping 47 matching lines @@
     int pixelDelta = oldestSize.width() * oldestSize.height();
 
     s_currentResourceUsePixels -= pixelDelta;
     adjustedSize = adjustSize(size);
     s_currentResourceUsePixels += pixelDelta;
 
     evictContext = !adjustedSize.isEmpty();
     return adjustedSize;
 }
 
-void DrawingBuffer::reset(const IntSize& newSize)
+bool DrawingBuffer::reset(const IntSize& newSize)
 {
-    if (!m_context)
-        return;
-
+    ASSERT(!newSize.isEmpty());
     IntSize adjustedSize;
     bool evictContext = false;
     bool isNewContext = m_size.isEmpty();
     if (s_allowContextEvictionOnCreate && isNewContext)
         adjustedSize = adjustSizeWithContextEviction(newSize, evictContext);
     else
         adjustedSize = adjustSize(newSize);
 
     if (adjustedSize.isEmpty())
-        return;
+        return false;
 
     if (evictContext)
         m_contextEvictionManager->forciblyLoseOldestContext("WARNING: WebGL contexts have exceeded the maximum allowed backbuffer area. Oldest context will be lost.");
 
     if (adjustedSize != m_size) {
         do {
             // resize multisample FBO
             if (!resizeMultisampleFramebuffer(adjustedSize) || !resizeFramebuffer(adjustedSize)) {
                 adjustedSize.scale(s_resourceAdjustedRatio);
                 continue;
             }
             break;
         } while (!adjustedSize.isEmpty());
 
         setSize(adjustedSize);
 
         if (adjustedSize.isEmpty())
-            return;
+            return false;
     }
 
     m_context->disable(GL_SCISSOR_TEST);
     m_context->clearColor(0, 0, 0, 0);
     m_context->colorMask(true, true, true, true);
 
     GLbitfield clearMask = GL_COLOR_BUFFER_BIT;
     if (m_attributes.depth) {
         m_context->clearDepth(1.0f);
         clearMask |= GL_DEPTH_BUFFER_BIT;
         m_context->depthMask(true);
     }
     if (m_attributes.stencil) {
         m_context->clearStencil(0);
         clearMask |= GL_STENCIL_BUFFER_BIT;
         m_context->stencilMaskSeparate(GL_FRONT, 0xFFFFFFFF);
     }
 
     clearFramebuffers(clearMask);
+    return true;
 }
 
 void DrawingBuffer::commit(long x, long y, long width, long height)
 {
-    if (!m_context)
-        return;
-
     if (width < 0)
         width = m_size.width();
     if (height < 0)
         height = m_size.height();
 
     m_context->makeContextCurrent();
 
     if (m_multisampleFBO && !m_contentsChangeCommitted) {
         m_context->bindFramebuffer(GL_READ_FRAMEBUFFER_ANGLE, m_multisampleFBO);
         m_context->bindFramebuffer(GL_DRAW_FRAMEBUFFER_ANGLE, m_fbo);
 
         if (m_scissorEnabled)
             m_context->disable(GL_SCISSOR_TEST);
 
         // Use NEAREST, because there is no scale performed during the blit.
         m_context->blitFramebufferCHROMIUM(x, y, width, height, x, y, width, height, GL_COLOR_BUFFER_BIT, GL_NEAREST);
 
         if (m_scissorEnabled)
             m_context->enable(GL_SCISSOR_TEST);
     }
 
     m_context->bindFramebuffer(GL_FRAMEBUFFER, m_fbo);
     m_contentsChangeCommitted = true;
 }
 
 void DrawingBuffer::restoreFramebufferBinding()
 {
-    if (!m_context || !m_framebufferBinding)
+    if (!m_framebufferBinding)
         return;
 
     m_context->bindFramebuffer(GL_FRAMEBUFFER, m_framebufferBinding);
 }
 
 bool DrawingBuffer::multisample() const
 {
     return m_attributes.antialias && m_multisampleExtensionSupported;
 }
 
 void DrawingBuffer::bind()
 {
-    if (!m_context)
-        return;
-
     m_context->bindFramebuffer(GL_FRAMEBUFFER, m_multisampleFBO ? m_multisampleFBO : m_fbo);
 }
 
 void DrawingBuffer::setPackAlignment(GLint param)
 {
     m_packAlignment = param;
 }
 
 void DrawingBuffer::paintRenderingResultsToCanvas(ImageBuffer* imageBuffer)
 {
@@ skipping 111 matching lines @@
     }
 }
 
 void DrawingBuffer::texImage2DResourceSafe(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, GLint unpackAlignment)
 {
     ASSERT(unpackAlignment == 1 || unpackAlignment == 2 || unpackAlignment == 4 || unpackAlignment == 8);
     m_context->texImage2D(target, level, internalformat, width, height, border, format, type, 0);
 }
 
 } // namespace WebCore