WebGL 2: add read/write framebuffer binding points to related APIs

Source/core/html/canvas/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 205 matching lines @@
         }
         break;
     }
 }
 
 namespace {
 
     class ScopedDrawingBufferBinder {
         STACK_ALLOCATED();
     public:
-        ScopedDrawingBufferBinder(DrawingBuffer* drawingBuffer, WebGLFramebuffer* framebufferBinding)
+        ScopedDrawingBufferBinder(DrawingBuffer* drawingBuffer, WebGLFramebuffer* framebufferBinding, GLenum target)
             : m_drawingBuffer(drawingBuffer)
             , m_framebufferBinding(framebufferBinding)
+            , m_target(target)
         {
             // Commit DrawingBuffer if needed (e.g., for multisampling)
             if (!m_framebufferBinding && m_drawingBuffer)
-                m_drawingBuffer->commit();
+                m_drawingBuffer->commit(m_target);
         }
 
         ~ScopedDrawingBufferBinder()
         {
             // Restore DrawingBuffer if needed
             if (!m_framebufferBinding && m_drawingBuffer)
-                m_drawingBuffer->bind();
+                m_drawingBuffer->bind(m_target);
         }
 
     private:
         DrawingBuffer* m_drawingBuffer;
         RawPtrWillBeMember<WebGLFramebuffer> m_framebufferBinding;
+        GLenum m_target;
     };
 
     GLint clamp(GLint value, GLint min, GLint max)
     {
         if (value < min)
             value = min;
         if (value > max)
             value = max;
         return value;
     }
@@ skipping 655 matching lines @@
     }
     if (contextAttributes.get().stencil()) {
         if (combinedClear && (mask & GL_STENCIL_BUFFER_BIT))
             webContext()->clearStencil(m_clearStencil & m_stencilMask);
         else
             webContext()->clearStencil(0);
         clearMask |= GL_STENCIL_BUFFER_BIT;
         webContext()->stencilMaskSeparate(GL_FRONT, 0xFFFFFFFF);
     }
 
-    drawingBuffer()->clearFramebuffers(clearMask);
+    if (!isWebGL2OrHigher())
+        drawingBuffer()->clearFramebuffers(clearMask);
+    else
+        drawingBuffer()->clearFramebuffers(clearMask, GL_DRAW_FRAMEBUFFER);

[Ken Russell (switch to Gerrit), 2015/05/06 21:17:33]

Please add a new virtual function that returns the enum GL_FRAMEBUFFER in
WebGLRenderingContextBase or GL_DRAW_FRAMEBUFFER in WebGL2RenderingContextBase.
This would eliminate the multiple if-tests here.

[yunchao, 2015/05/22 09:54:35]

Done.

 
     restoreStateAfterClear();
-    if (m_framebufferBinding)
-        webContext()->bindFramebuffer(GL_FRAMEBUFFER, objectOrZero(m_framebufferBinding.get()));
+    if (m_framebufferBinding) {
+        if (!isWebGL2OrHigher())
+            webContext()->bindFramebuffer(GL_FRAMEBUFFER, objectOrZero(m_framebufferBinding.get()));
+        else
+            webContext()->bindFramebuffer(GL_DRAW_FRAMEBUFFER, objectOrZero(m_framebufferBinding.get()));
+    }
     drawingBuffer()->setBufferClearNeeded(false);
 
     return combinedClear ? CombinedClear : JustClear;
 }
 
 void WebGLRenderingContextBase::restoreStateAfterClear()
 {
     if (isContextLost())
         return;
 
@@ skipping 84 matching lines @@
     width = clamp(width, 1, maxWidth);
     height = clamp(height, 1, maxHeight);
 
     // 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));
     restoreStateAfterClear();
 
     webContext()->bindTexture(GL_TEXTURE_2D, objectOrZero(m_textureUnits[m_activeTextureUnit].m_texture2DBinding.get()));
     webContext()->bindRenderbuffer(GL_RENDERBUFFER, objectOrZero(m_renderbufferBinding.get()));
-    if (m_framebufferBinding)
+    if (isWebGL2OrHigher()) {
+    // In GLES 3.0, bindFramebuffer(GL_FRAMEBUFFER, buffer1) = bindBuffer(GL_READ_FRAMEBUFFER, buffer1) +
+    // bindFramebuffer(GL_DRAW_FRAMEBUFFER, buffer1)
+        if (m_framebufferBinding)
+            webContext()->bindFramebuffer(GL_DRAW_FRAMEBUFFER, objectOrZero(m_framebufferBinding.get()));
+        WebGLFramebuffer* readFramebufferBinding = getFramebufferBinding(GL_READ_FRAMEBUFFER);
+        if (readFramebufferBinding)
+            webContext()->bindFramebuffer(GL_READ_FRAMEBUFFER, objectOrZero(readFramebufferBinding));
+    } else if (m_framebufferBinding) {
         webContext()->bindFramebuffer(GL_FRAMEBUFFER, objectOrZero(m_framebufferBinding.get()));
+    }
 }
 
 int WebGLRenderingContextBase::drawingBufferWidth() const
 {
     return isContextLost() ? 0 : drawingBuffer()->size().width();
 }
 
 int WebGLRenderingContextBase::drawingBufferHeight() const
 {
     return isContextLost() ? 0 : drawingBuffer()->size().height();
@@ skipping 327 matching lines @@
 
 bool WebGLRenderingContextBase::validateFramebufferTarget(GLenum target)
 {
     if (target == GL_FRAMEBUFFER)
         return true;
     return false;
 }
 
 WebGLFramebuffer* WebGLRenderingContextBase::getFramebufferBinding(GLenum target)
 {
-    return m_framebufferBinding.get();
+    if (target == GL_FRAMEBUFFER)
+        return m_framebufferBinding.get();
+    return nullptr;
 }
 
 GLenum WebGLRenderingContextBase::checkFramebufferStatus(GLenum target)
 {
     if (isContextLost())
         return GL_FRAMEBUFFER_UNSUPPORTED;
     if (!validateFramebufferTarget(target)) {
         synthesizeGLError(GL_INVALID_ENUM, "checkFramebufferStatus", "invalid target");
         return 0;
     }
-    if (!getFramebufferBinding(target) || !getFramebufferBinding(target)->object())
+    WebGLFramebuffer* framebufferBinding = getFramebufferBinding(target);
+    if (!framebufferBinding || !framebufferBinding->object())
         return GL_FRAMEBUFFER_COMPLETE;
     const char* reason = "framebuffer incomplete";
-    GLenum result = m_framebufferBinding->checkStatus(&reason);
+    GLenum result = framebufferBinding->checkStatus(&reason, target);
     if (result != GL_FRAMEBUFFER_COMPLETE) {
         emitGLWarning("checkFramebufferStatus", reason);
         return result;
     }
     result = webContext()->checkFramebufferStatus(target);
     return result;
 }
 
 void WebGLRenderingContextBase::clear(GLbitfield mask)
 {
@@ skipping 149 matching lines @@
         return;
     if (!isTexInternalFormatColorBufferCombinationValid(internalformat, boundFramebufferColorFormat())) {
         synthesizeGLError(GL_INVALID_OPERATION, "copyTexImage2D", "framebuffer is incompatible format");
         return;
     }
     if (isNPOTStrict() && level && WebGLTexture::isNPOT(width, height)) {
         synthesizeGLError(GL_INVALID_VALUE, "copyTexImage2D", "level > 0 not power of 2");
         return;
     }
     const char* reason = "framebuffer incomplete";
-    if (m_framebufferBinding && !m_framebufferBinding->onAccess(webContext(), &reason)) {
+    if ((m_framebufferBinding && !m_framebufferBinding->onAccess(webContext(), &reason))
+        || (getFramebufferBinding(GL_READ_FRAMEBUFFER) && !getFramebufferBinding(GL_READ_FRAMEBUFFER)->onAccess(webContext(), &reason, GL_READ_FRAMEBUFFER))) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, "copyTexImage2D", reason);
         return;
     }
     clearIfComposited();
-    ScopedDrawingBufferBinder binder(drawingBuffer(), m_framebufferBinding.get());
+    ScopedDrawingBufferBinder binder(drawingBuffer(), m_framebufferBinding.get(), GL_FRAMEBUFFER);
+    if (isWebGL2OrHigher())
+        ScopedDrawingBufferBinder readBinder(drawingBuffer(), getFramebufferBinding(GL_READ_FRAMEBUFFER), GL_READ_FRAMEBUFFER);

[Ken Russell (switch to Gerrit), 2015/05/06 21:17:33]

This won't work. The scoping of readBinder ends outside the if-clause. Please
rethink this.

[yunchao, 2015/05/22 09:54:35]

I am very sorry, Ken. I didn't got what you said. What is the problem that the
readBinder ends outside the if-clause? when the function come to the end, the
destructor of readBinder will be executed for WebGL2RenderingContext. It seems
to be correct. Could you kindly explain the potential error? Many thanks!

     webContext()->copyTexImage2D(target, level, internalformat, x, y, width, height, border);
     // FIXME: if the framebuffer is not complete, none of the below should be executed.
     tex->setLevelInfo(target, level, internalformat, width, height, 1, GL_UNSIGNED_BYTE);
 }
 
 void WebGLRenderingContextBase::copyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width, GLsizei height)
 {
     if (isContextLost())
         return;
     if (!validateTexFuncLevel("copyTexSubImage2D", target, level))
@@ skipping 17 matching lines @@
         return;
     }
     GLenum internalformat = tex->getInternalFormat(target, level);
     if (!validateSettableTexFormat("copyTexSubImage2D", internalformat))
         return;
     if (!isTexInternalFormatColorBufferCombinationValid(internalformat, boundFramebufferColorFormat())) {
         synthesizeGLError(GL_INVALID_OPERATION, "copyTexSubImage2D", "framebuffer is incompatible format");
         return;
     }
     const char* reason = "framebuffer incomplete";
-    if (m_framebufferBinding && !m_framebufferBinding->onAccess(webContext(), &reason)) {
+    if ((m_framebufferBinding && !m_framebufferBinding->onAccess(webContext(), &reason))
+        || (getFramebufferBinding(GL_READ_FRAMEBUFFER) && !getFramebufferBinding(GL_READ_FRAMEBUFFER)->onAccess(webContext(), &reason, GL_READ_FRAMEBUFFER))) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, "copyTexSubImage2D", reason);
         return;
     }
     clearIfComposited();
-    ScopedDrawingBufferBinder binder(drawingBuffer(), m_framebufferBinding.get());
+    ScopedDrawingBufferBinder binder(drawingBuffer(), m_framebufferBinding.get(), GL_FRAMEBUFFER);
+    if (isWebGL2OrHigher())
+        ScopedDrawingBufferBinder readBinder(drawingBuffer(), getFramebufferBinding(GL_READ_FRAMEBUFFER), GL_READ_FRAMEBUFFER);

[Ken Russell (switch to Gerrit), 2015/05/06 21:17:33]

Same problem here.

     webContext()->copyTexSubImage2D(target, level, xoffset, yoffset, x, y, width, height);
 }
 
 PassRefPtrWillBeRawPtr<WebGLBuffer> WebGLRenderingContextBase::createBuffer()
 {
     if (isContextLost())
         return nullptr;
     RefPtrWillBeRawPtr<WebGLBuffer> o = WebGLBuffer::create(this);
     addSharedObject(o.get());
     return o.release();
@@ skipping 123 matching lines @@
 }
 
 void WebGLRenderingContextBase::deleteRenderbuffer(WebGLRenderbuffer* renderbuffer)
 {
     if (!deleteObject(renderbuffer))
         return;
     if (renderbuffer == m_renderbufferBinding)
         m_renderbufferBinding = nullptr;
     if (m_framebufferBinding)
         m_framebufferBinding->removeAttachmentFromBoundFramebuffer(renderbuffer);
+    if (getFramebufferBinding(GL_READ_FRAMEBUFFER))
+        getFramebufferBinding(GL_READ_FRAMEBUFFER)->removeAttachmentFromBoundFramebuffer(renderbuffer, GL_READ_FRAMEBUFFER);
 }
 
 void WebGLRenderingContextBase::deleteShader(WebGLShader* shader)
 {
     deleteObject(shader);
 }
 
 void WebGLRenderingContextBase::deleteTexture(WebGLTexture* texture)
 {
     if (!deleteObject(texture))
@@ skipping 17 matching lines @@
                 maxBoundTextureIndex = i;
             }
             if (texture == m_textureUnits[i].m_texture2DArrayBinding) {
                 m_textureUnits[i].m_texture2DArrayBinding = nullptr;
                 maxBoundTextureIndex = i;
             }
         }
     }
     if (m_framebufferBinding)
         m_framebufferBinding->removeAttachmentFromBoundFramebuffer(texture);
+    if (getFramebufferBinding(GL_READ_FRAMEBUFFER))
+        getFramebufferBinding(GL_READ_FRAMEBUFFER)->removeAttachmentFromBoundFramebuffer(texture, GL_READ_FRAMEBUFFER);
 
     // If the deleted was bound to the the current maximum index, trace backwards to find the new max texture index
     if (m_onePlusMaxNonDefaultTextureUnit == static_cast<unsigned long>(maxBoundTextureIndex + 1)) {
         findNewMaxNonDefaultTextureUnit();
     }
 }
 
 void WebGLRenderingContextBase::depthFunc(GLenum func)
 {
     if (isContextLost())
@@ skipping 199 matching lines @@
         synthesizeGLError(GL_INVALID_ENUM, "framebufferRenderbuffer", "invalid target");
         return;
     }
     if (buffer && !buffer->validate(contextGroup(), this)) {
         synthesizeGLError(GL_INVALID_OPERATION, "framebufferRenderbuffer", "no buffer or buffer not from this context");
         return;
     }
     // Don't allow the default framebuffer to be mutated; all current
     // implementations use an FBO internally in place of the default
     // FBO.
-    if (!m_framebufferBinding || !m_framebufferBinding->object()) {
+    WebGLFramebuffer* framebufferBinding = getFramebufferBinding(target);
+    if (!framebufferBinding || !framebufferBinding->object()) {
         synthesizeGLError(GL_INVALID_OPERATION, "framebufferRenderbuffer", "no framebuffer bound");
         return;
     }
     Platform3DObject bufferObject = objectOrZero(buffer);
     switch (attachment) {
     case GC3D_DEPTH_STENCIL_ATTACHMENT_WEBGL:
+        // TODO. are there any devices can support depth_stencil buffer directly, not use oes_depth_stencil extension?
         if (isDepthStencilSupported() || !buffer) {
             webContext()->framebufferRenderbuffer(target, GL_DEPTH_ATTACHMENT, renderbuffertarget, bufferObject);
             webContext()->framebufferRenderbuffer(target, GL_STENCIL_ATTACHMENT, renderbuffertarget, bufferObject);
         } else {
             WebGLRenderbuffer* emulatedStencilBuffer = ensureEmulatedStencilBuffer(renderbuffertarget, buffer);
             if (!emulatedStencilBuffer) {
                 synthesizeGLError(GL_OUT_OF_MEMORY, "framebufferRenderbuffer", "out of memory");
                 return;
             }
             webContext()->framebufferRenderbuffer(target, GL_DEPTH_ATTACHMENT, renderbuffertarget, bufferObject);
             webContext()->framebufferRenderbuffer(target, GL_STENCIL_ATTACHMENT, renderbuffertarget, objectOrZero(emulatedStencilBuffer));
         }
         break;
     default:
         webContext()->framebufferRenderbuffer(target, attachment, renderbuffertarget, bufferObject);
     }
-    m_framebufferBinding->setAttachmentForBoundFramebuffer(attachment, buffer);
+    framebufferBinding->setAttachmentForBoundFramebuffer(target, attachment, buffer);
     applyStencilTest();
 }
 
 void WebGLRenderingContextBase::framebufferTexture2D(GLenum target, GLenum attachment, GLenum textarget, WebGLTexture* texture, GLint level)
 {
     if (isContextLost() || !validateFramebufferFuncParameters("framebufferTexture2D", target, attachment))
         return;
     if (level) {
         synthesizeGLError(GL_INVALID_VALUE, "framebufferTexture2D", "level not 0");
         return;
     }
     if (texture && !texture->validate(contextGroup(), this)) {
         synthesizeGLError(GL_INVALID_OPERATION, "framebufferTexture2D", "no texture or texture not from this context");
         return;
     }
     // Don't allow the default framebuffer to be mutated; all current
     // implementations use an FBO internally in place of the default
     // FBO.
-    if (!m_framebufferBinding || !m_framebufferBinding->object()) {
+    WebGLFramebuffer* framebufferBinding = getFramebufferBinding(target);
+    if (!framebufferBinding || !framebufferBinding->object()) {
         synthesizeGLError(GL_INVALID_OPERATION, "framebufferTexture2D", "no framebuffer bound");
         return;
     }
     Platform3DObject textureObject = objectOrZero(texture);
     switch (attachment) {
     case GC3D_DEPTH_STENCIL_ATTACHMENT_WEBGL:
         webContext()->framebufferTexture2D(target, GL_DEPTH_ATTACHMENT, textarget, textureObject, level);
         webContext()->framebufferTexture2D(target, GL_STENCIL_ATTACHMENT, textarget, textureObject, level);
         break;
-    case GL_DEPTH_ATTACHMENT:
-        webContext()->framebufferTexture2D(target, attachment, textarget, textureObject, level);
-        break;
-    case GL_STENCIL_ATTACHMENT:
-        webContext()->framebufferTexture2D(target, attachment, textarget, textureObject, level);
-        break;
     default:
         webContext()->framebufferTexture2D(target, attachment, textarget, textureObject, level);
     }
-    m_framebufferBinding->setAttachmentForBoundFramebuffer(attachment, textarget, texture, level);
+    // TODO: Check whether this is correct

[bajones, 2015/05/06 17:47:54]

Let's figure this out before landing the patch.

[yunchao, 2015/05/22 09:54:35]

I think this is correct. So remove this TODO.

+    framebufferBinding->setAttachmentForBoundFramebuffer(target, attachment, textarget, texture, level);
     applyStencilTest();
 }
 
 void WebGLRenderingContextBase::frontFace(GLenum mode)
 {
     if (isContextLost())
         return;
     switch (mode) {
     case GL_CW:
     case GL_CCW:
@@ skipping 1233 matching lines @@
             synthesizeGLError(GL_INVALID_OPERATION, "readPixels", "format/type not RGBA/UNSIGNED_BYTE or implementation-defined values");
             return;
         }
     }
     // Validate array type against pixel type.
     if (pixels->type() != expectedViewType) {
         synthesizeGLError(GL_INVALID_OPERATION, "readPixels", "ArrayBufferView was the wrong type for the pixel format");
         return;
     }
     const char* reason = "framebuffer incomplete";
-    if (m_framebufferBinding && !m_framebufferBinding->onAccess(webContext(), &reason)) {
+    GLenum target = isWebGL2OrHigher() ? GL_READ_FRAMEBUFFER : GL_FRAMEBUFFER;
+    WebGLFramebuffer* readFramebufferBinding = getFramebufferBinding(target);
+    if (readFramebufferBinding && !readFramebufferBinding->onAccess(webContext(), &reason, target)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, "readPixels", reason);
         return;
     }
     // Calculate array size, taking into consideration of PACK_ALIGNMENT.
     unsigned totalBytesRequired = 0;
     unsigned padding = 0;
     GLenum error = WebGLImageConversion::computeImageSizeInBytes(format, type, width, height, m_packAlignment, &totalBytesRequired, &padding);
     if (error != GL_NO_ERROR) {
         synthesizeGLError(error, "readPixels", "invalid dimensions");
         return;
     }
     if (pixels->byteLength() < totalBytesRequired) {
         synthesizeGLError(GL_INVALID_OPERATION, "readPixels", "ArrayBufferView not large enough for dimensions");
         return;
     }
 
     clearIfComposited();
     void* data = pixels->baseAddress();
 
     {
-        ScopedDrawingBufferBinder binder(drawingBuffer(), m_framebufferBinding.get());
+        ScopedDrawingBufferBinder binder(drawingBuffer(), readFramebufferBinding, target);
         webContext()->readPixels(x, y, width, height, format, type, data);
     }
 
 #if OS(MACOSX)
     // FIXME: remove this section when GL driver bug on Mac is fixed, i.e.,
     // when alpha is off, readPixels should set alpha to 255 instead of 0.
-    if (!m_framebufferBinding && !drawingBuffer()->getActualAttributes().alpha) {
+    if (!readFramebufferBinding && !drawingBuffer()->getActualAttributes().alpha) {
         unsigned char* pixels = reinterpret_cast<unsigned char*>(data);
         for (GLsizei iy = 0; iy < height; ++iy) {
             for (GLsizei ix = 0; ix < width; ++ix) {
                 pixels[3] = 255;
                 pixels += 4;
             }
             pixels += padding;
         }
     }
 #endif
@@ skipping 2710 matching lines @@
 
 void WebGLRenderingContextBase::setFramebuffer(GLenum target, WebGLFramebuffer* buffer)
 {
     if (buffer)
         buffer->setHasEverBeenBound();
 
     if (target == GL_FRAMEBUFFER || target == GL_DRAW_FRAMEBUFFER) {
         m_framebufferBinding = buffer;
         applyStencilTest();
     }
-    drawingBuffer()->setFramebufferBinding(objectOrZero(m_framebufferBinding.get()));
+    drawingBuffer()->setFramebufferBinding(objectOrZero(getFramebufferBinding(target)), target);
 
     if (!buffer) {
         // Instead of binding fb 0, bind the drawing buffer.
         drawingBuffer()->bind(target);
     } else {
         webContext()->bindFramebuffer(target, buffer->object());
     }
 }
 
 void WebGLRenderingContextBase::restoreCurrentFramebuffer()
@@ skipping 96 matching lines @@
     return m_sharedWebGraphicsContext3D ? m_sharedWebGraphicsContext3D->drawingBuffer() : 0;
 }
 #else
 DrawingBuffer* WebGLRenderingContextBase::drawingBuffer() const
 {
     return m_drawingBuffer.get();
 }
 #endif
 
 } // namespace blink