WebGL GL_RGB emulation to support IOSurfaces on Mac.

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 82 matching lines @@
 #include "public/platform/Platform.h"
 #include "public/platform/WebGraphicsContext3D.h"
 #include "public/platform/WebGraphicsContext3DProvider.h"
 #include "public/platform/functional/WebFunction.h"
 #include "wtf/Functional.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/text/StringBuilder.h"
 #include "wtf/text/StringUTF8Adaptor.h"
 #include "wtf/typed_arrays/ArrayBufferContents.h"
 
+#include <memory>
+
 namespace blink {
 
 namespace {
 
 const double secondsBetweenRestoreAttempts = 1.0;
 const int maxGLErrorsAllowedToConsole = 256;
 const unsigned maxGLActiveContexts = 16;
 
 using WebGLRenderingContextBaseSet = PersistentHeapHashSet<WeakMember<WebGLRenderingContextBase>>;
 WebGLRenderingContextBaseSet& activeContexts()
 {
     DEFINE_STATIC_LOCAL(WebGLRenderingContextBaseSet, activeContexts, ());
     return activeContexts;
 }
 
 using WebGLRenderingContextBaseMap = PersistentHeapHashMap<WeakMember<WebGLRenderingContextBase>, int>;
 WebGLRenderingContextBaseMap& forciblyEvictedContexts()
 {
     DEFINE_STATIC_LOCAL(WebGLRenderingContextBaseMap, forciblyEvictedContexts, ());
     return forciblyEvictedContexts;
 }
 
+class ScopedRGBEmulationColorMask {

[Zhenyao Mo, 2016/04/29 22:54:15]

Does this bug also exist in core profile?  If yes, then you need to expose it to
.h file, and use it in WebGL2RenderingContextBase also (a few draw calls there).

[erikchen, 2016/05/03 22:58:07]

It does. I've done as you suggested.

+public:
+    ScopedRGBEmulationColorMask(gpu::gles2::GLES2Interface* contextGL, GLboolean* colorMask)
+        : m_contextGL(contextGL)
+    {
+        memcpy(m_colorMask, colorMask, 4 * sizeof(GLboolean));
+        m_contextGL->ColorMask(m_colorMask[0], m_colorMask[1], m_colorMask[2], false);
+    }
+    ~ScopedRGBEmulationColorMask()
+    {
+        m_contextGL->ColorMask(m_colorMask[0], m_colorMask[1], m_colorMask[2], m_colorMask[3]);
+    }
+
+private:
+    gpu::gles2::GLES2Interface* m_contextGL;
+    GLboolean m_colorMask[4];
+};
+
 } // namespace
 
 void WebGLRenderingContextBase::forciblyLoseOldestContext(const String& reason)
 {
     WebGLRenderingContextBase* candidate = oldestContext();
     if (!candidate)
         return;
 
     candidate->printWarningToConsole(reason);
     InspectorInstrumentation::didFireWebGLWarning(candidate->canvas());
@@ skipping 975 matching lines @@
 
     contextGL()->Disable(GL_SCISSOR_TEST);
     if (combinedClear && (mask & GL_COLOR_BUFFER_BIT)) {
         contextGL()->ClearColor(m_colorMask[0] ? m_clearColor[0] : 0,
             m_colorMask[1] ? m_clearColor[1] : 0,
             m_colorMask[2] ? m_clearColor[2] : 0,
             m_colorMask[3] ? m_clearColor[3] : 0);
     } else {
         contextGL()->ClearColor(0, 0, 0, 0);
     }
-    contextGL()->ColorMask(true, true, true, true);
+    contextGL()->ColorMask(true, true, true, !drawingBuffer()->requiresRGBEmulation());
     GLbitfield clearMask = GL_COLOR_BUFFER_BIT;
     if (contextAttributes.get().depth()) {
         if (!combinedClear || !m_depthMask || !(mask & GL_DEPTH_BUFFER_BIT))
             contextGL()->ClearDepthf(1.0f);
         clearMask |= GL_DEPTH_BUFFER_BIT;
         contextGL()->DepthMask(true);
     }
     if (contextAttributes.get().stencil() || drawingBuffer()->hasImplicitStencilBuffer()) {
         if (combinedClear && (mask & GL_STENCIL_BUFFER_BIT))
             contextGL()->ClearStencil(m_clearStencil & m_stencilMask);
@@ skipping 271 matching lines @@
         return;
     if (deleted)
         renderBuffer = 0;
     if (target != GL_RENDERBUFFER) {
         synthesizeGLError(GL_INVALID_ENUM, "bindRenderbuffer", "invalid target");
         return;
     }
     m_renderbufferBinding = renderBuffer;
     contextGL()->BindRenderbuffer(target, objectOrZero(renderBuffer));
     preserveObjectWrapper(scriptState, this, "renderbuffer", 0, renderBuffer);
+
+    drawingBuffer()->setRenderbufferBinding(objectOrZero(renderBuffer));
+
     if (renderBuffer)
         renderBuffer->setHasEverBeenBound();
 }
 
 void WebGLRenderingContextBase::bindTexture(ScriptState* scriptState, GLenum target, WebGLTexture* texture)
 {
     bool deleted;
     if (!checkObjectToBeBound("bindTexture", texture, deleted))
         return;
     if (deleted)
@@ skipping 218 matching lines @@
         return;
     if (mask & ~(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT)) {
         synthesizeGLError(GL_INVALID_VALUE, "clear", "invalid mask");
         return;
     }
     const char* reason = "framebuffer incomplete";
     if (m_framebufferBinding && m_framebufferBinding->checkDepthStencilStatus(&reason) != GL_FRAMEBUFFER_COMPLETE) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, "clear", reason);
         return;
     }
+
+    std::unique_ptr<ScopedRGBEmulationColorMask> scopedColorMask;

[Ken Russell (switch to Gerrit), 2016/04/29 09:33:09]

I'd suggest changing ScopedRGBEmulationColorMask's constructor to take
contextGL, the color mask, and the drawing buffer, and internalize whether it
does its work. That way this block can just be

ScopedRGBEmulationColorMask scopedColorMask(contextGL(), m_colorMask,
m_drawingBuffer);

throughout the CL.

[erikchen, 2016/05/03 22:58:07]

Done.

+    if (m_drawingBuffer->requiresRGBEmulation())
+        scopedColorMask.reset(new ScopedRGBEmulationColorMask(contextGL(), m_colorMask));
+
     if (clearIfComposited(mask) != CombinedClear) {
         // If clearing the default back buffer's depth buffer, also clear the stencil buffer, if one
         // was allocated implicitly. This avoids performance problems on some GPUs.
         if (!m_framebufferBinding && drawingBuffer()->hasImplicitStencilBuffer() && (mask & GL_DEPTH_BUFFER_BIT)) {
             // It shouldn't matter what value it's cleared to, since in other queries in the API, we
             // claim that the stencil buffer doesn't exist.
             mask |= GL_STENCIL_BUFFER_BIT;
         }
         contextGL()->Clear(mask);
     }
@@ skipping 251 matching lines @@
 {
     deleteObject(program);
     // We don't reset m_currentProgram to 0 here because the deletion of the
     // current program is delayed.
 }
 
 void WebGLRenderingContextBase::deleteRenderbuffer(WebGLRenderbuffer* renderbuffer)
 {
     if (!deleteObject(renderbuffer))
         return;
-    if (renderbuffer == m_renderbufferBinding)
+    if (renderbuffer == m_renderbufferBinding) {
         m_renderbufferBinding = nullptr;
+        drawingBuffer()->setRenderbufferBinding(0);
+    }
     if (m_framebufferBinding)
         m_framebufferBinding->removeAttachmentFromBoundFramebuffer(GL_FRAMEBUFFER, renderbuffer);
     if (getFramebufferBinding(GL_READ_FRAMEBUFFER))
         getFramebufferBinding(GL_READ_FRAMEBUFFER)->removeAttachmentFromBoundFramebuffer(GL_READ_FRAMEBUFFER, renderbuffer);
 }
 
 void WebGLRenderingContextBase::deleteShader(WebGLShader* shader)
 {
     deleteObject(shader);
 }
@@ skipping 127 matching lines @@
         return false;
     }
     return true;
 }
 
 void WebGLRenderingContextBase::drawArrays(GLenum mode, GLint first, GLsizei count)
 {
     if (!validateDrawArrays("drawArrays"))
         return;
 
+    std::unique_ptr<ScopedRGBEmulationColorMask> scopedColorMask;
+    if (m_drawingBuffer->requiresRGBEmulation())
+        scopedColorMask.reset(new ScopedRGBEmulationColorMask(contextGL(), m_colorMask));
     clearIfComposited();
     contextGL()->DrawArrays(mode, first, count);
     markContextChanged(CanvasChanged);
 }
 
 void WebGLRenderingContextBase::drawElements(GLenum mode, GLsizei count, GLenum type, long long offset)
 {
     if (!validateDrawElements("drawElements", type, offset))
         return;
 
     if (transformFeedbackActive() && !transformFeedbackPaused()) {
         synthesizeGLError(GL_INVALID_OPERATION, "drawElements", "transform feedback is active and not paused");
         return;
     }
 
+    std::unique_ptr<ScopedRGBEmulationColorMask> scopedColorMask;
+    if (m_drawingBuffer->requiresRGBEmulation())
+        scopedColorMask.reset(new ScopedRGBEmulationColorMask(contextGL(), m_colorMask));
     clearIfComposited();
     contextGL()->DrawElements(mode, count, type, reinterpret_cast<void*>(static_cast<intptr_t>(offset)));
     markContextChanged(CanvasChanged);
 }
 
 void WebGLRenderingContextBase::drawArraysInstancedANGLE(GLenum mode, GLint first, GLsizei count, GLsizei primcount)
 {
     if (!validateDrawArrays("drawArraysInstancedANGLE"))
         return;
 
+    std::unique_ptr<ScopedRGBEmulationColorMask> scopedColorMask;
+    if (m_drawingBuffer->requiresRGBEmulation())
+        scopedColorMask.reset(new ScopedRGBEmulationColorMask(contextGL(), m_colorMask));
     clearIfComposited();
     contextGL()->DrawArraysInstancedANGLE(mode, first, count, primcount);
     markContextChanged(CanvasChanged);
 }
 
 void WebGLRenderingContextBase::drawElementsInstancedANGLE(GLenum mode, GLsizei count, GLenum type, long long offset, GLsizei primcount)
 {
     if (!validateDrawElements("drawElementsInstancedANGLE", type, offset))
         return;
 
+    std::unique_ptr<ScopedRGBEmulationColorMask> scopedColorMask;
+    if (m_drawingBuffer->requiresRGBEmulation())
+        scopedColorMask.reset(new ScopedRGBEmulationColorMask(contextGL(), m_colorMask));
     clearIfComposited();
     contextGL()->DrawElementsInstancedANGLE(mode, count, type, reinterpret_cast<void*>(static_cast<intptr_t>(offset)), primcount);
     markContextChanged(CanvasChanged);
 }
 
 void WebGLRenderingContextBase::enable(GLenum cap)
 {
     if (isContextLost() || !validateCapability("enable", cap))
         return;
     if (cap == GL_STENCIL_TEST) {
@@ skipping 411 matching lines @@
         return ScriptValue::createNull(scriptState);
     const int intZero = 0;
     switch (pname) {
     case GL_ACTIVE_TEXTURE:
         return getUnsignedIntParameter(scriptState, pname);
     case GL_ALIASED_LINE_WIDTH_RANGE:
         return getWebGLFloatArrayParameter(scriptState, pname);
     case GL_ALIASED_POINT_SIZE_RANGE:
         return getWebGLFloatArrayParameter(scriptState, pname);
     case GL_ALPHA_BITS:
+        if (m_drawingBuffer->requiresRGBEmulation())
+            return WebGLAny(scriptState, 0);
         return getIntParameter(scriptState, pname);
     case GL_ARRAY_BUFFER_BINDING:
         return WebGLAny(scriptState, m_boundArrayBuffer.get());
     case GL_BLEND:
         return getBooleanParameter(scriptState, pname);
     case GL_BLEND_COLOR:
         return getWebGLFloatArrayParameter(scriptState, pname);
     case GL_BLEND_DST_ALPHA:
         return getUnsignedIntParameter(scriptState, pname);
     case GL_BLEND_DST_RGB:
@@ skipping 2401 matching lines @@
     if (isContextLost())
         return;
 
     m_contextLostMode = mode;
     ASSERT(m_contextLostMode != NotLostContext);
     m_autoRecoveryMethod = autoRecoveryMethod;
 
     // Make absolutely sure we do not refer to an already-deleted texture or framebuffer.
     drawingBuffer()->setTexture2DBinding(0);
     drawingBuffer()->setFramebufferBinding(GL_FRAMEBUFFER, 0);
+    drawingBuffer()->setRenderbufferBinding(0);
 
     detachAndRemoveAllObjects();
 
     // Lose all the extensions.
     for (size_t i = 0; i < m_extensions.size(); ++i) {
         ExtensionTracker* tracker = m_extensions[i];
         tracker->loseExtension(false);
     }
 
     for (size_t i = 0; i < WebGLExtensionNameCount; ++i)
@@ skipping 1255 matching lines @@
         contextGL()->PixelStorei(GL_UNPACK_ALIGNMENT, 1);
 }
 
 void WebGLRenderingContextBase::restoreUnpackParameters()
 {
     if (m_unpackAlignment != 1)
         contextGL()->PixelStorei(GL_UNPACK_ALIGNMENT, m_unpackAlignment);
 }
 
 } // namespace blink