commit bd2bdf9f964e20d3275cfc4cc49cc8f033b17c04
author Jamie Madill <jmadill@chromium.org> Thu Mar 26 15:40:09 2020 -0400
committer Jamie Madill <jmadill@chromium.org> Fri Mar 27 20:02:32 2020 +0000
tree b0d041e974d9fde19fda320f2defa6e04656f9cc
parent 0bba11009682ece5fafcbaac1c2654732ec0b6d4

Fix feedback loop clearing detection.

Bug: angleproject:4517
Change-Id: I3231b129718019f83495843404cd011eb2cd480d
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2122689
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tobin Ehlis <tobine@google.com>

src/libANGLE/Framebuffer.cpp

diff --git a/src/libANGLE/Framebuffer.cpp b/src/libANGLE/Framebuffer.cpp
index 8a2508f..f1c009c 100644
--- a/src/libANGLE/Framebuffer.cpp
+++ b/src/libANGLE/Framebuffer.cpp
@@ -679,31 +679,35 @@
     return mId == Framebuffer::kDefaultDrawFramebufferHandle;
 }
 
-bool FramebufferState::updateAttachmentFeedbackLoop(size_t dirtyBit)
+bool FramebufferState::updateAttachmentFeedbackLoopAndReturnIfChanged(size_t dirtyBit)
 {
+    bool previous;
     bool loop;
 
     switch (dirtyBit)
     {
         case Framebuffer::DIRTY_BIT_DEPTH_ATTACHMENT:
+            previous                 = mDepthBufferFeedbackLoop;
             loop                     = mDepthAttachment.isBoundAsSamplerOrImage();
             mDepthBufferFeedbackLoop = loop;
             break;
 
         case Framebuffer::DIRTY_BIT_STENCIL_ATTACHMENT:
+            previous                   = mStencilBufferFeedbackLoop;
             loop                       = mStencilAttachment.isBoundAsSamplerOrImage();
             mStencilBufferFeedbackLoop = loop;
             break;
 
         default:
             ASSERT(dirtyBit <= Framebuffer::DIRTY_BIT_COLOR_ATTACHMENT_MAX);
-            loop = mColorAttachments[dirtyBit].isBoundAsSamplerOrImage();
+            previous = mDrawBufferFeedbackLoops.test(dirtyBit);
+            loop     = mColorAttachments[dirtyBit].isBoundAsSamplerOrImage();
             mDrawBufferFeedbackLoops[dirtyBit] = loop;
             break;
     }
 
     updateHasRenderingFeedbackLoop();
-    return loop;
+    return previous != loop;
 }
 
 void FramebufferState::updateHasRenderingFeedbackLoop()
@@ -1942,7 +1946,7 @@
     mState.mResourceNeedsInit.set(dirtyBit, attachment->initState() == InitState::MayNeedInit);
     onDirtyBinding->bind(resource);
 
-    mState.updateAttachmentFeedbackLoop(dirtyBit);
+    mState.updateAttachmentFeedbackLoopAndReturnIfChanged(dirtyBit);
     invalidateCompletenessCache();
 }
 
@@ -1978,7 +1982,7 @@
         // Triggered by changes to Texture feedback loops.
         if (message == angle::SubjectMessage::BindingChanged)
         {
-            if (mState.updateAttachmentFeedbackLoop(index))
+            if (mState.updateAttachmentFeedbackLoopAndReturnIfChanged(index))
             {
                 mDirtyBits.set(index);
                 onStateChange(angle::SubjectMessage::DirtyBitsFlagged);

src/libANGLE/Framebuffer.h

diff --git a/src/libANGLE/Framebuffer.h b/src/libANGLE/Framebuffer.h
index 39bcdf1..7a30997 100644
--- a/src/libANGLE/Framebuffer.h
+++ b/src/libANGLE/Framebuffer.h
@@ -132,7 +132,9 @@
     const FramebufferAttachment *getWebGLDepthStencilAttachment() const;
     const FramebufferAttachment *getWebGLDepthAttachment() const;
     const FramebufferAttachment *getWebGLStencilAttachment() const;
-    bool updateAttachmentFeedbackLoop(size_t dirtyBit);
+
+    // Returns true if there was a change in this attachments feedback-loop-ness.
+    bool updateAttachmentFeedbackLoopAndReturnIfChanged(size_t dirtyBit);
     void updateHasRenderingFeedbackLoop();
 
     friend class Framebuffer;