commit 6be602dc699aadb9c2c33389ceb062a8a05fc458
author He Yunchao <yunchao.he@intel.com> Thu Dec 22 14:33:07 2016 +0800
committer Commit Bot <commit-bot@chromium.org> Tue Jan 03 16:38:04 2017 +0000
tree 82ce331352316a7edc29b5cf7b79e4418edced3a
parent d68924e52c55722571f7b5af9c771c96c2b0d0da

Some improvements for BlitFramebuffer.

This change can
1. Skip color blitting when draw buffers are disabled.
2. Skip depth/stencil blitting when depth/stencil buffer has no image.
3. Return early if possible.
4. Move the logic above from D3D backend to common part.

BUG=angleproject:1677

Change-Id: I1662d214b72fb8caa4a95c86d9b8a67984b6071a
Reviewed-on: https://chromium-review.googlesource.com/423135
Commit-Queue: Yunchao He <yunchao.he@intel.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>

src/libANGLE/Framebuffer.cpp

diff --git a/src/libANGLE/Framebuffer.cpp b/src/libANGLE/Framebuffer.cpp
index 72886d6..6efe537 100644
--- a/src/libANGLE/Framebuffer.cpp
+++ b/src/libANGLE/Framebuffer.cpp
@@ -840,7 +840,31 @@
                         GLbitfield mask,
                         GLenum filter)
 {
-    return mImpl->blit(context, sourceArea, destArea, mask, filter);
+    GLbitfield blitMask = mask;
+
+    // Note that blitting is called against draw framebuffer.
+    // See the code in gl::Context::blitFramebuffer.
+    if ((mask & GL_COLOR_BUFFER_BIT) && !hasEnabledDrawBuffer())
+    {
+        blitMask &= ~GL_COLOR_BUFFER_BIT;
+    }
+
+    if ((mask & GL_STENCIL_BUFFER_BIT) && mState.getStencilAttachment() == nullptr)
+    {
+        blitMask &= ~GL_STENCIL_BUFFER_BIT;
+    }
+
+    if ((mask & GL_DEPTH_BUFFER_BIT) && mState.getDepthAttachment() == nullptr)
+    {
+        blitMask &= ~GL_DEPTH_BUFFER_BIT;
+    }
+
+    if (!blitMask)
+    {
+        return NoError();
+    }
+
+    return mImpl->blit(context, sourceArea, destArea, blitMask, filter);
 }
 
 int Framebuffer::getSamples(const ContextState &state)

src/libANGLE/renderer/d3d/FramebufferD3D.cpp

diff --git a/src/libANGLE/renderer/d3d/FramebufferD3D.cpp b/src/libANGLE/renderer/d3d/FramebufferD3D.cpp
index f6eef6f..e86f913 100644
--- a/src/libANGLE/renderer/d3d/FramebufferD3D.cpp
+++ b/src/libANGLE/renderer/d3d/FramebufferD3D.cpp
@@ -263,38 +263,10 @@
 {
     const auto &glState                      = context->getGLState();
     const gl::Framebuffer *sourceFramebuffer = glState.getReadFramebuffer();
-    bool blitRenderTarget = false;
-    if ((mask & GL_COLOR_BUFFER_BIT) && sourceFramebuffer->getReadColorbuffer() != nullptr &&
-        mState.getFirstColorAttachment() != nullptr)
-    {
-        blitRenderTarget = true;
-    }
-
-    bool blitStencil = false;
-    if ((mask & GL_STENCIL_BUFFER_BIT) && sourceFramebuffer->getStencilbuffer() != nullptr &&
-        mState.getStencilAttachment() != nullptr)
-    {
-        blitStencil = true;
-    }
-
-    bool blitDepth = false;
-    if ((mask & GL_DEPTH_BUFFER_BIT) && sourceFramebuffer->getDepthbuffer() != nullptr &&
-        mState.getDepthAttachment() != nullptr)
-    {
-        blitDepth = true;
-    }
-
-    if (blitRenderTarget || blitDepth || blitStencil)
-    {
-        const gl::Rectangle *scissor =
-            glState.isScissorTestEnabled() ? &glState.getScissor() : nullptr;
-        gl::Error error = blitImpl(sourceArea, destArea, scissor, blitRenderTarget, blitDepth,
-                                   blitStencil, filter, sourceFramebuffer);
-        if (error.isError())
-        {
-            return error;
-        }
-    }
+    const gl::Rectangle *scissor = glState.isScissorTestEnabled() ? &glState.getScissor() : nullptr;
+    ANGLE_TRY(blitImpl(sourceArea, destArea, scissor, (mask & GL_COLOR_BUFFER_BIT) != 0,
+                       (mask & GL_DEPTH_BUFFER_BIT) != 0, (mask & GL_STENCIL_BUFFER_BIT) != 0,
+                       filter, sourceFramebuffer));
 
     return gl::Error(GL_NO_ERROR);
 }