commit 47f6dd0d4a21564350d845720d5cf14b158dba12
author Qin Jiajia <jiajia.qin@intel.com> Fri Aug 10 13:36:32 2018 +0800
committer Commit Bot <commit-bot@chromium.org> Tue Aug 28 07:50:50 2018 +0000
tree 0a8f94423c2d1c5940b1df3123ac2e5eaa076020
parent 4e877ad3ed4d5c687736b3fd497c58c05047aefc

Implement robust initialization for image texture

This change fixes a bug that the image texture initialization time is not
correct. It happens when we use compute shader to write data to an
uninitialized texture, then use readPixels to read the result which
results that texture initialization falls behind image store and
covers the real result.

Bug: angleproject:2766

Change-Id: I4e986972096857afc975c40dfa4d559a2f31194c
Reviewed-on: https://chromium-review.googlesource.com/1170569
Commit-Queue: Jiajia Qin <jiajia.qin@intel.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>

src/libANGLE/Program.cpp

diff --git a/src/libANGLE/Program.cpp b/src/libANGLE/Program.cpp
index 834f737..bd05861 100644
--- a/src/libANGLE/Program.cpp
+++ b/src/libANGLE/Program.cpp
@@ -770,10 +770,11 @@
 }
 
 // ImageBinding implementation.
-ImageBinding::ImageBinding(size_t count) : boundImageUnits(count, 0)
+ImageBinding::ImageBinding(size_t count) : boundImageUnits(count, 0), unreferenced(false)
 {
 }
-ImageBinding::ImageBinding(GLuint imageUnit, size_t count)
+ImageBinding::ImageBinding(GLuint imageUnit, size_t count, bool unreferenced)
+    : unreferenced(unreferenced)
 {
     for (size_t index = 0; index < count; ++index)
     {
@@ -861,6 +862,17 @@
     return uniformIndex - mSamplerUniformRange.low();
 }
 
+bool ProgramState::isImageUniformIndex(GLuint index) const
+{
+    return mImageUniformRange.contains(index);
+}
+
+GLuint ProgramState::getImageIndexFromUniformIndex(GLuint uniformIndex) const
+{
+    ASSERT(isImageUniformIndex(uniformIndex));
+    return uniformIndex - mImageUniformRange.low();
+}
+
 GLuint ProgramState::getAttributeLocation(const std::string &name) const
 {
     for (const sh::Attribute &attribute : mAttributes)
@@ -1291,10 +1303,12 @@
     updateLinkedShaderStages();
 
     // Mark implementation-specific unreferenced uniforms as ignored.
-    mProgram->markUnusedUniformLocations(&mState.mUniformLocations, &mState.mSamplerBindings);
+    mProgram->markUnusedUniformLocations(&mState.mUniformLocations, &mState.mSamplerBindings,
+                                         &mState.mImageBindings);
 
     // Must be called after markUnusedUniformLocations.
     mState.updateActiveSamplers();
+    mState.updateActiveImages();
 
     setUniformValuesFromBindingQualifiers();
 
@@ -1361,6 +1375,20 @@
     }
 }
 
+void ProgramState::updateActiveImages()
+{
+    for (ImageBinding &imageBinding : mImageBindings)
+    {
+        if (imageBinding.unreferenced)
+            continue;
+
+        for (GLint imageUnit : imageBinding.boundImageUnits)
+        {
+            mActiveImagesMask.set(imageUnit);
+        }
+    }
+}
+
 // Returns the program object to an unlinked state, before re-linking, or at destruction
 void Program::unlink()
 {
@@ -1383,6 +1411,7 @@
     mState.mComputeShaderLocalSize.fill(1);
     mState.mSamplerBindings.clear();
     mState.mImageBindings.clear();
+    mState.mActiveImagesMask.reset();
     mState.mNumViews                          = -1;
     mState.mGeometryShaderInputPrimitiveType  = PrimitiveMode::Triangles;
     mState.mGeometryShaderOutputPrimitiveType = PrimitiveMode::TriangleStrip;
@@ -2860,7 +2889,7 @@
         else
         {
             mState.mImageBindings.emplace_back(
-                ImageBinding(imageUniform.binding, imageUniform.getBasicTypeElementCount()));
+                ImageBinding(imageUniform.binding, imageUniform.getBasicTypeElementCount(), false));
         }
 
         GLuint arraySize = imageUniform.isArray() ? imageUniform.arraySizes[0] : 1u;