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 85 matching lines @@
 #include "public/platform/Platform.h"
 #include "public/platform/WebGraphicsContext3D.h"
 #include "public/platform/WebGraphicsContext3DProvider.h"
 #include "public/platform/callback/WebClosure.h"
 #include "wtf/ArrayBufferContents.h"
 #include "wtf/Functional.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/text/StringBuilder.h"
 #include "wtf/text/StringUTF8Adaptor.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 {
+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;
 
     // This context could belong to a dead page and the last JavaScript reference has already
     // been lost. Garbage collection might be triggered in the middle of this function, for
@@ skipping 1021 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 23 matching lines @@
     contextGL()->ClearColor(m_clearColor[0], m_clearColor[1],
         m_clearColor[2], m_clearColor[3]);
     contextGL()->ColorMask(m_colorMask[0], m_colorMask[1],
         m_colorMask[2], m_colorMask[3]);
     contextGL()->ClearDepthf(m_clearDepth);
     contextGL()->ClearStencil(m_clearStencil);
     contextGL()->StencilMaskSeparate(GL_FRONT, m_stencilMask);
     contextGL()->DepthMask(m_depthMask);
 }
 
+void WebGLRenderingContextBase::moveGLErrorsToInternalQueue()
+{
+    DCHECK(!isContextLost());
+    GLenum error = GL_NO_ERROR;
+    while ((error = contextGL()->GetError()) != GL_NO_ERROR) {
+        if (!m_syntheticErrors.contains(error))
+            m_syntheticErrors.append(error);
+    }
+}
+
 void WebGLRenderingContextBase::markLayerComposited()
 {
     if (!isContextLost())
         drawingBuffer()->setBufferClearNeeded(true);
 }
 
 void WebGLRenderingContextBase::setIsHidden(bool hidden)
 {
     m_isHidden = hidden;
     if (drawingBuffer())
@@ skipping 466 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;
+    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 50 matching lines @@
 {
     if (isContextLost() || !validateWebGLObject("compileShader", shader))
         return;
     contextGL()->CompileShader(objectOrZero(shader));
 }
 
 void WebGLRenderingContextBase::compressedTexImage2D(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, DOMArrayBufferView* data)
 {
     if (isContextLost())
         return;
-    if (!validateTexture2DBinding("compressedTexImage2D", target))
+    WebGLTexture* texture = validateTexture2DBinding("compressedTexImage2D", target);
+    if (!texture)
         return;
     if (!validateCompressedTexFormat("compressedTexImage2D", internalformat))
         return;
+
+    moveGLErrorsToInternalQueue();
     contextGL()->CompressedTexImage2D(target, level, internalformat, width, height,
         border, data->byteLength(), data->baseAddress());
+
+    GLenum error = contextGL()->GetError();
+    if (error == GL_NO_ERROR) {
+        texture->setColorFormat(internalformat);
+    } else {
+        if (!m_syntheticErrors.contains(error))
+            m_syntheticErrors.append(error);
+    }
 }
 
 void WebGLRenderingContextBase::compressedTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, DOMArrayBufferView* data)
 {
     if (isContextLost())
         return;
     if (!validateTexture2DBinding("compressedTexSubImage2D", target))
         return;
     if (!validateCompressedTexFormat("compressedTexSubImage2D", format))
         return;
@@ skipping 25 matching lines @@
         return false;
     }
 
     return true;
 }
 
 void WebGLRenderingContextBase::copyTexImage2D(GLenum target, GLint level, GLenum internalformat, GLint x, GLint y, GLsizei width, GLsizei height, GLint border)
 {
     if (isContextLost())
         return;
-    if (!validateTexture2DBinding("copyTexImage2D", target))
+    WebGLTexture* texture = validateTexture2DBinding("copyTexImage2D", target);
+    if (!texture)
         return;
     if (!validateCopyTexFormat("copyTexImage2D", internalformat))
         return;
     if (!validateSettableTexFormat("copyTexImage2D", internalformat))
         return;
+
+    // If RGB emulation is required, then the destination format should not have
+    // an alpha channel.
+    if (drawingBuffer()->requiresRGBEmulation()) {
+        uint32_t channelsExist = WebGLImageConversion::getChannelBitsByFormat(GL_RGB);
+        uint32_t channelsNeeded = WebGLImageConversion::getChannelBitsByFormat(internalformat);
+        if ((channelsNeeded & channelsExist) != channelsNeeded) {
+            synthesizeGLError(GL_INVALID_OPERATION, "copyTexImage2D", "incompatible format");
+            return;
+        }
+    }
+
     WebGLFramebuffer* readFramebufferBinding = nullptr;
     if (!validateReadBufferAndGetInfo("copyTexImage2D", readFramebufferBinding))
         return;
     clearIfComposited();
     ScopedDrawingBufferBinder binder(drawingBuffer(), readFramebufferBinding);
+    moveGLErrorsToInternalQueue();
     contextGL()->CopyTexImage2D(target, level, internalformat, x, y, width, height, border);
+
+    GLenum error = contextGL()->GetError();
+    if (error == GL_NO_ERROR) {
+        texture->setColorFormat(internalformat);
+    } else {
+        if (!m_syntheticErrors.contains(error))
+            m_syntheticErrors.append(error);
+    }
 }
 
 void WebGLRenderingContextBase::copyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width, GLsizei height)
 {
     if (isContextLost())
         return;
-    if (!validateTexture2DBinding("copyTexSubImage2D", target))
+    WebGLTexture* texture = validateTexture2DBinding("copyTexSubImage2D", target);
+    if (!texture)
         return;
+
+    // If RGB emulation is required, then the destination format should not have
+    // an alpha channel.
+    if (drawingBuffer()->requiresRGBEmulation()) {
+        uint32_t channelsExist = WebGLImageConversion::getChannelBitsByFormat(GL_RGB);
+        uint32_t channelsNeeded = WebGLImageConversion::getChannelBitsByFormat(texture->getColorFormat());
+        if ((channelsNeeded & channelsExist) != channelsNeeded) {
+            synthesizeGLError(GL_INVALID_OPERATION, "copyTexSubImage2D", "incompatible format");
+            return;
+        }
+    }
+
     WebGLFramebuffer* readFramebufferBinding = nullptr;
     if (!validateReadBufferAndGetInfo("copyTexSubImage2D", readFramebufferBinding))
         return;
     clearIfComposited();
     ScopedDrawingBufferBinder binder(drawingBuffer(), readFramebufferBinding);
     contextGL()->CopyTexSubImage2D(target, level, xoffset, yoffset, x, y, width, height);
 }
 
 WebGLBuffer* WebGLRenderingContextBase::createBuffer()
 {
@@ skipping 259 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 1304 matching lines @@
         && extensionsUtil()->isExtensionEnabled("GL_CHROMIUM_color_buffer_float_rgba"))
         return GL_RGBA32F_EXT;
     if (type == GL_FLOAT && internalformat == GL_RGB
         && extensionsUtil()->isExtensionEnabled("GL_CHROMIUM_color_buffer_float_rgb"))
         return GL_RGB32F_EXT;
     return internalformat;
 }
 
 void WebGLRenderingContextBase::texImage2DBase(GLenum target, GLint level, GLint internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, const void* pixels)
 {
+    moveGLErrorsToInternalQueue();
+
     // All calling functions check isContextLost, so a duplicate check is not needed here.
     contextGL()->TexImage2D(target, level, convertTexInternalFormat(internalformat, type), width, height, border, format, type, pixels);
+
+    GLenum error = contextGL()->GetError();

[Ken Russell (switch to Gerrit), 2016/04/06 00:02:53]

Sorry, but this synchronous GetError call will kill texture upload performance.
A different solution is needed, as mentioned in
https://bugs.chromium.org/p/chromium/issues/detail?id=595948#c18 .

+    if (error == GL_NO_ERROR) {
+        WebGLTexture* texture = validateTexture2DBinding("texImage2DBase", target);
+        if (texture)
+            texture->setColorFormat(format);
+    } else {
+        if (!m_syntheticErrors.contains(error))
+            m_syntheticErrors.append(error);
+    }
 }
 
 void WebGLRenderingContextBase::texImage2DImpl(GLenum target, GLint level, GLint internalformat, GLenum format, GLenum type, Image* image, WebGLImageConversion::ImageHtmlDomSource domSource, bool flipY, bool premultiplyAlpha)
 {
     // All calling functions check isContextLost, so a duplicate check is not needed here.
     if (type == GL_UNSIGNED_INT_10F_11F_11F_REV) {
         // The UNSIGNED_INT_10F_11F_11F_REV type pack/unpack isn't implemented.
         type = GL_FLOAT;
     }
     Vector<uint8_t> data;
@@ skipping 2431 matching lines @@
         contextGL()->PixelStorei(GL_UNPACK_ALIGNMENT, 1);
 }
 
 void WebGLRenderingContextBase::restoreUnpackParameters()
 {
     if (m_unpackAlignment != 1)
         contextGL()->PixelStorei(GL_UNPACK_ALIGNMENT, m_unpackAlignment);
 }
 
 } // namespace blink