Removed arbitrary 4096 size limit on WebGL canvas backbuffers, Take 2

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 602 matching lines @@
     }
 }
 
 bool DrawingBuffer::resizeFramebuffer(const IntSize& size)
 {
     // resize regular FBO
     m_context->bindFramebuffer(GL_FRAMEBUFFER, m_fbo);
 
     m_context->bindTexture(GL_TEXTURE_2D, m_colorBuffer.textureId);
 
-    allocateTextureMemory(&m_colorBuffer, size);
+    if (!allocateTextureMemory(&m_colorBuffer, size))
+        return false;
 
     if (m_multisampleMode == ImplicitResolve)
         m_context->framebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_colorBuffer.textureId, 0, m_sampleCount);
     else
         m_context->framebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_colorBuffer.textureId, 0);
 
     m_context->bindTexture(GL_TEXTURE_2D, 0);
 
-    if (m_multisampleMode != ExplicitResolve)
-        resizeDepthStencil(size);
+    if (m_multisampleMode != ExplicitResolve) {
+        if (!resizeDepthStencil(size))
+            return false;
+    }
     if (m_context->checkFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
         return false;
 
     return true;
 }
 
 bool DrawingBuffer::resizeMultisampleFramebuffer(const IntSize& size)
 {
     if (m_multisampleMode == ExplicitResolve) {
         m_context->bindFramebuffer(GL_FRAMEBUFFER, m_multisampleFBO);
 
         m_context->bindRenderbuffer(GL_RENDERBUFFER, m_multisampleColorBuffer);
         m_context->renderbufferStorageMultisampleCHROMIUM(GL_RENDERBUFFER, m_sampleCount, m_internalRenderbufferFormat, size.width(), size.height());
 
         if (m_context->getError() == GL_OUT_OF_MEMORY)
             return false;
 
         m_context->framebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, m_multisampleColorBuffer);
-        resizeDepthStencil(size);
+        if (!resizeDepthStencil(size))
+            return false;
         if (m_context->checkFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
             return false;
     }
 
     return true;
 }
 
-void DrawingBuffer::resizeDepthStencil(const IntSize& size)
+bool DrawingBuffer::resizeDepthStencil(const IntSize& size)
 {
     if (!m_requestedAttributes.depth && !m_requestedAttributes.stencil)
-        return;
+        return true;
 
     if (m_packedDepthStencilExtensionSupported) {
         if (!m_depthStencilBuffer)
             m_depthStencilBuffer = m_context->createRenderbuffer();
         m_context->bindRenderbuffer(GL_RENDERBUFFER, m_depthStencilBuffer);
         if (m_multisampleMode == ImplicitResolve)
             m_context->renderbufferStorageMultisampleEXT(GL_RENDERBUFFER, m_sampleCount, GL_DEPTH24_STENCIL8_OES, size.width(), size.height());
         else if (m_multisampleMode == ExplicitResolve)
             m_context->renderbufferStorageMultisampleCHROMIUM(GL_RENDERBUFFER, m_sampleCount, GL_DEPTH24_STENCIL8_OES, size.width(), size.height());
         else
@@ skipping 20 matching lines @@
             if (m_multisampleMode == ImplicitResolve)
                 m_context->renderbufferStorageMultisampleEXT(GL_RENDERBUFFER, m_sampleCount, GL_STENCIL_INDEX8, size.width(), size.height());
             else if (m_multisampleMode == ExplicitResolve)
                 m_context->renderbufferStorageMultisampleCHROMIUM(GL_RENDERBUFFER, m_sampleCount, GL_STENCIL_INDEX8, size.width(), size.height());
             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);
+
+    if (m_context->getError() == GL_OUT_OF_MEMORY)
+        return false;

[Ken Russell (switch to Gerrit), 2015/03/31 02:13:33]

There's a preexisting bug with all of the getError() calls in this file. If it
happened that the user caused a GL error then these checks may return the other
error and miss the out-of-memory error.

In order to fix this, the m_lostContextErrors in WebGLRenderingContextBase
should be generalized to be used all the time, and a method for copying the
"real" GL errors from the WebGraphicsContext3D into it should be added. Then
before WebGLRenderingContextBase calls into DrawingBuffer, the
WebGLRenderingContextBase should copy the real errors into itself. Care is
needed to watch out for lost contexts.

Would you either add this mechanism in this CL or file a bug about doing so?
Thanks.

+
+    return true;
 }
 
 
 
 void DrawingBuffer::clearFramebuffers(GLbitfield clearMask)
 {
     // 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->clear(GL_COLOR_BUFFER_BIT);
@@ skipping 242 matching lines @@
         memcpy(rowA, scanline, rowBytes);
     }
 }
 
 void DrawingBuffer::texImage2DResourceSafe(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, GLint unpackAlignment)
 {
     ASSERT(unpackAlignment == 1 || unpackAlignment == 2 || unpackAlignment == 4 || unpackAlignment == 8);
     m_context->texImage2D(target, level, internalformat, width, height, border, format, type, 0);
 }
 
-void DrawingBuffer::allocateTextureMemory(TextureInfo* info, const IntSize& size)
+bool DrawingBuffer::allocateTextureMemory(TextureInfo* info, const IntSize& size)
 {
     if (RuntimeEnabledFeatures::webGLImageChromiumEnabled()) {
         deleteChromiumImageForTexture(info);
 
         info->imageId = m_context->createGpuMemoryBufferImageCHROMIUM(size.width(), size.height(), GL_RGBA, GC3D_SCANOUT_CHROMIUM);
+
+        if (m_context->getError() == GL_OUT_OF_MEMORY)
+            return false;
+
         if (info->imageId) {
             m_context->bindTexImage2DCHROMIUM(GL_TEXTURE_2D, info->imageId);
-            return;
+            return true;
         }
     }
 
     texImage2DResourceSafe(GL_TEXTURE_2D, 0, m_internalColorFormat, size.width(), size.height(), 0, m_colorFormat, GL_UNSIGNED_BYTE);
+
+    if (m_context->getError() == GL_OUT_OF_MEMORY)
+        return false;
+
+    return true;
 }
 
 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