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

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 105 matching lines @@
     PassOwnPtr<Extensions3DUtil> extensionsUtil,
     bool multisampleExtensionSupported,
     bool packedDepthStencilExtensionSupported,
     bool discardFramebufferSupported,
     PreserveDrawingBuffer preserve,
     WebGraphicsContext3D::Attributes requestedAttributes)
     : m_preserveDrawingBuffer(preserve)
     , m_scissorEnabled(false)
     , m_texture2DBinding(0)
     , m_framebufferBinding(0)
+    , m_readFramebufferBinding(0)
     , m_activeTextureUnit(GL_TEXTURE0)
     , m_context(context)
     , m_extensionsUtil(extensionsUtil)
     , m_size(-1, -1)
     , m_requestedAttributes(requestedAttributes)
     , m_multisampleExtensionSupported(multisampleExtensionSupported)
     , m_packedDepthStencilExtensionSupported(packedDepthStencilExtensionSupported)
     , m_discardFramebufferSupported(discardFramebufferSupported)
     , m_fbo(0)
     , m_depthStencilBuffer(0)
@@ skipping 562 matching lines @@
             else
                 m_context->renderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX8, size.width(), size.height());
             m_context->framebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, m_stencilBuffer);
         }
     }
     m_context->bindRenderbuffer(GL_RENDERBUFFER, 0);
 }
 
 
 
-void DrawingBuffer::clearFramebuffers(GLbitfield clearMask)
+void DrawingBuffer::clearFramebuffers(GLbitfield clearMask, GLenum target)
 {
     // We will clear the multisample FBO, but we also need to clear the non-multisampled buffer.
     if (m_multisampleFBO) {
-        m_context->bindFramebuffer(GL_FRAMEBUFFER, m_fbo);
+        m_context->bindFramebuffer(target, m_fbo);

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

Let's add an ASSERT that target == GL_FRAMEBUFFER || target ==
GL_DRAW_FRAMEBUFFER. This code wouldn't make sense if the caller passed in
GL_READ_FRAMEBUFFER.

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

Done.

         m_context->clear(GL_COLOR_BUFFER_BIT);
     }
 
-    m_context->bindFramebuffer(GL_FRAMEBUFFER, m_multisampleFBO ? m_multisampleFBO : m_fbo);
+    m_context->bindFramebuffer(target, m_multisampleFBO ? m_multisampleFBO : m_fbo);
     m_context->clear(clearMask);
 }
 
 void DrawingBuffer::setSize(const IntSize& size)
 {
     if (m_size == size)
         return;
 
     m_size = size;
 }
@@ skipping 48 matching lines @@
     if (m_actualAttributes.stencil) {
         m_context->clearStencil(0);
         clearMask |= GL_STENCIL_BUFFER_BIT;
         m_context->stencilMaskSeparate(GL_FRONT, 0xFFFFFFFF);
     }
 
     clearFramebuffers(clearMask);
     return true;
 }
 
-void DrawingBuffer::commit()
+void DrawingBuffer::commit(GLenum target)
 {
     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);
 
         int width = m_size.width();
         int height = m_size.height();
         // Use NEAREST, because there is no scale performed during the blit.
         m_context->blitFramebufferCHROMIUM(0, 0, width, height, 0, 0, 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_context->bindFramebuffer(target, m_fbo);
     m_contentsChangeCommitted = true;
 }
 
-void DrawingBuffer::restoreFramebufferBinding()
+void DrawingBuffer::restoreFramebufferBinding(GLenum target)
 {
-    if (!m_framebufferBinding) {
-        bind();
+    if (((target == GL_FRAMEBUFFER || target == GL_DRAW_FRAMEBUFFER) && !m_framebufferBinding)
+        || (target == GL_READ_FRAMEBUFFER && !m_readFramebufferBinding)) {
+        bind(target);
         return;
     }
-    m_context->bindFramebuffer(GL_FRAMEBUFFER, m_framebufferBinding);
+    m_context->bindFramebuffer(target, target == GL_READ_FRAMEBUFFER ? m_readFramebufferBinding : m_framebufferBinding);
 }
 
 bool DrawingBuffer::multisample() const
 {
     return m_multisampleMode != None;
 }
 
 void DrawingBuffer::bind(GLenum target)
 {
     m_context->bindFramebuffer(target, m_multisampleFBO ? m_multisampleFBO : m_fbo);
@@ skipping 157 matching lines @@
 void DrawingBuffer::deleteChromiumImageForTexture(TextureInfo* info)
 {
     if (info->imageId) {
         m_context->releaseTexImage2DCHROMIUM(GL_TEXTURE_2D, info->imageId);
         m_context->destroyImageCHROMIUM(info->imageId);
         info->imageId = 0;
     }
 }
 
 } // namespace blink