Remove alpha/depth/stencil/antialias from WGC3D::Attributes.

third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp

 /*
  * Copyright (C) 2009 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 544 matching lines @@
     }
     Settings* settings = frame->settings();
 
     // The FrameLoaderClient might block creation of a new WebGL context despite the page settings; in
     // particular, if WebGL contexts were lost one or more times via the GL_ARB_robustness extension.
     if (!frame->loader().client()->allowWebGL(settings && settings->webGLEnabled())) {
         canvas->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextcreationerror, false, true, "Web page was not allowed to create a WebGL context."));
         return nullptr;
     }
 
-    WebGraphicsContext3D::Attributes wgc3dAttributes = toWebGraphicsContext3DAttributes(attributes, document.topDocument().url().getString(), settings, webGLVersion);
+    WebGraphicsContext3D::Attributes wgc3dAttributes = toWebGraphicsContext3DAttributes(attributes, document.topDocument().url().getString(), webGLVersion);
     Platform::GraphicsInfo glInfo;
     glInfo.testFailContext = shouldFailContextCreationForTesting;
     OwnPtr<WebGraphicsContext3DProvider> contextProvider = adoptPtr(Platform::current()->createOffscreenGraphicsContext3DProvider(wgc3dAttributes, 0, &glInfo));
     if (!contextProvider || shouldFailContextCreationForTesting) {
         shouldFailContextCreationForTesting = false;
         canvas->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextcreationerror, false, true, extractWebGLContextCreationError(glInfo)));
         return nullptr;
     }
     gpu::gles2::GLES2Interface* gl = contextProvider->contextGL();
     if (!String(gl->GetString(GL_EXTENSIONS)).contains("GL_OES_packed_depth_stencil")) {
@@ skipping 297 matching lines @@
     }
 
     ADD_VALUES_TO_SET(m_supportedInternalFormats, kSupportedInternalFormatsES2);
     ADD_VALUES_TO_SET(m_supportedInternalFormatsCopyTexImage, kSupportedInternalFormatsES2);
     ADD_VALUES_TO_SET(m_supportedFormats, kSupportedFormatsES2);
     ADD_VALUES_TO_SET(m_supportedTypes, kSupportedTypesES2);
 }
 
 PassRefPtr<DrawingBuffer> WebGLRenderingContextBase::createDrawingBuffer(PassOwnPtr<WebGraphicsContext3DProvider> contextProvider)
 {
-    WebGraphicsContext3D::Attributes attrs;
-    attrs.alpha = m_requestedAttributes.alpha();
-    attrs.depth = m_requestedAttributes.depth();
-    attrs.stencil = m_requestedAttributes.stencil();
-    attrs.antialias = m_requestedAttributes.antialias();
     bool premultipliedAlpha = m_requestedAttributes.premultipliedAlpha();
+    bool wantAlphaChannel = m_requestedAttributes.alpha();
+    bool wantDepthBuffer = m_requestedAttributes.depth();
+    bool wantStencilBuffer = m_requestedAttributes.stencil();
+    bool wantAntialiasing = m_requestedAttributes.antialias();

[danakj, 2016/03/31 20:27:56]

WebGL can still turn off MSAA if the author requests, that was never broken.

     DrawingBuffer::PreserveDrawingBuffer preserve = m_requestedAttributes.preserveDrawingBuffer() ? DrawingBuffer::Preserve : DrawingBuffer::Discard;
-    return DrawingBuffer::create(contextProvider, clampedCanvasSize(), premultipliedAlpha, preserve, attrs);
+    return DrawingBuffer::create(
+        contextProvider,
+        clampedCanvasSize(),
+        premultipliedAlpha,
+        wantAlphaChannel,
+        wantDepthBuffer,
+        wantStencilBuffer,
+        wantAntialiasing,
+        preserve);
 }
 
 void WebGLRenderingContextBase::initializeNewContext()
 {
     ASSERT(!isContextLost());
     ASSERT(drawingBuffer());
 
     m_markedCanvasDirty = false;
     m_activeTextureUnit = 0;
     m_packAlignment = 4;
@@ skipping 391 matching lines @@
     int currentArea = width * height;
     if (currentArea > maxArea) {
         // If we've exceeded the area limit scale the buffer down, preserving ascpect ratio, until it fits.
         float scaleFactor = sqrtf(static_cast<float>(maxArea) / static_cast<float>(currentArea));
         width = std::max(1, static_cast<int>(width * scaleFactor));
         height = std::max(1, static_cast<int>(height * scaleFactor));
     }
 
     // We don't have to mark the canvas as dirty, since the newly created image buffer will also start off
     // clear (and this matches what reshape will do).
-    drawingBuffer()->reset(IntSize(width, height));
+    bool wantAlphaChannel = m_requestedAttributes.alpha();

[danakj, 2016/03/31 20:27:56]

I assume that m_requestedAttributes is still valid here, please confirm.

+    bool wantDepthBuffer = m_requestedAttributes.depth();
+    bool wantStencilBuffer = m_requestedAttributes.stencil();
+    drawingBuffer()->reset(IntSize(width, height), wantAlphaChannel, wantDepthBuffer || wantStencilBuffer);
     restoreStateAfterClear();
 
     contextGL()->BindTexture(GL_TEXTURE_2D, objectOrZero(m_textureUnits[m_activeTextureUnit].m_texture2DBinding.get()));
     contextGL()->BindRenderbuffer(GL_RENDERBUFFER, objectOrZero(m_renderbufferBinding.get()));
     drawingBuffer()->restoreFramebufferBindings();
 }
 
 int WebGLRenderingContextBase::drawingBufferWidth() const
 {
     return isContextLost() ? 0 : drawingBuffer()->size().width();
@@ skipping 1086 matching lines @@
     }
 }
 
 void WebGLRenderingContextBase::getContextAttributes(Nullable<WebGLContextAttributes>& result)
 {
     if (isContextLost())
         return;
     result.set(m_requestedAttributes);
     // Some requested attributes may not be honored, so we need to query the underlying
     // context/drawing buffer and adjust accordingly.
-    WebGraphicsContext3D::Attributes attrs = drawingBuffer()->getActualAttributes();
-    if (m_requestedAttributes.depth() && !attrs.depth)
+    if (m_requestedAttributes.depth() && !drawingBuffer()->hasDepthBuffer())
         result.get().setDepth(false);
-    if (m_requestedAttributes.stencil() && !attrs.stencil)
+    if (m_requestedAttributes.stencil() && !drawingBuffer()->hasStencilBuffer())
         result.get().setStencil(false);
     result.get().setAntialias(drawingBuffer()->multisample());
 }
 
 GLenum WebGLRenderingContextBase::getError()
 {
     if (!m_lostContextErrors.isEmpty()) {
         GLenum error = m_lostContextErrors.first();
         m_lostContextErrors.remove(0);
         return error;
@@ skipping 3570 matching lines @@
 
     if (!frame->loader().client()->allowWebGL(settings && settings->webGLEnabled()))
         return;
 
     // If the context was lost due to RealLostContext, we need to destroy the old DrawingBuffer before creating new DrawingBuffer to ensure resource budget enough.
     if (drawingBuffer()) {
         m_drawingBuffer->beginDestruction();
         m_drawingBuffer.clear();
     }
 
-    WebGraphicsContext3D::Attributes attributes = toWebGraphicsContext3DAttributes(m_requestedAttributes, canvas()->document().topDocument().url().getString(), settings, version());
+    WebGraphicsContext3D::Attributes attributes = toWebGraphicsContext3DAttributes(m_requestedAttributes, canvas()->document().topDocument().url().getString(), version());
     Platform::GraphicsInfo glInfo;
     OwnPtr<WebGraphicsContext3DProvider> contextProvider = adoptPtr(Platform::current()->createOffscreenGraphicsContext3DProvider(attributes, 0, &glInfo));
     RefPtr<DrawingBuffer> buffer;
     if (contextProvider) {
         // Construct a new drawing buffer with the new WebGraphicsContext3D.
         buffer = createDrawingBuffer(contextProvider.release());
         // If DrawingBuffer::create() fails to allocate a fbo, |drawingBuffer| is set to null.
     }
     if (!buffer) {
         if (m_contextLostMode == RealLostContext) {
@@ skipping 330 matching lines @@
         contextGL()->PixelStorei(GL_UNPACK_ALIGNMENT, 1);
 }
 
 void WebGLRenderingContextBase::restoreUnpackParameters()
 {
     if (m_unpackAlignment != 1)
         contextGL()->PixelStorei(GL_UNPACK_ALIGNMENT, m_unpackAlignment);
 }
 
 } // namespace blink