Fix a thread safety issue in the GL image worker.

LLViewerTexture::mNeedsCreateTexture needs to be an attomic bool since
it is written both in the main thread and in the GL image worker thread.

We can now enable threaded bump maps creation as a result of this fix.

I have read the CLA Document and I hereby sign the CLA

3 files changed, 15 insertions, 10 deletions

diff --git a/indra/newview/lldrawpoolbump.cpp b/indra/newview/lldrawpoolbump.cpp
index 8db6a10e26..ed991a2bbf 100644
--- a/indra/newview/lldrawpoolbump.cpp
+++ b/indra/newview/lldrawpoolbump.cpp
@@ -77,7 +77,9 @@ static S32 cube_channel = -1;
 static S32 diffuse_channel = -1;
 static S32 bump_channel = -1;
 
-#define LL_BUMPLIST_MULTITHREADED 0 // TODO -- figure out why this doesn't work
+// Enabled after changing LLViewerTexture::mNeedsCreateTexture to an
+// LLAtomicBool; this should work just fine, now. HB
+#define LL_BUMPLIST_MULTITHREADED 1
 
 // static 
 void LLStandardBumpmap::init()
diff --git a/indra/newview/llviewertexture.cpp b/indra/newview/llviewertexture.cpp
index e3ac56d0d3..8a11c5cf8f 100644
--- a/indra/newview/llviewertexture.cpp
+++ b/indra/newview/llviewertexture.cpp
@@ -1118,7 +1118,7 @@ void LLViewerFetchedTexture::init(bool firstinit)
 	mLoadedCallbackDesiredDiscardLevel = S8_MAX;
 	mPauseLoadedCallBacks = FALSE;
 
-	mNeedsCreateTexture = FALSE;
+	mNeedsCreateTexture = false;
 	
 	mIsRawImageValid = FALSE;
 	mRawDiscardLevel = INVALID_DISCARD_LEVEL;
@@ -1400,12 +1400,12 @@ void LLViewerFetchedTexture::addToCreateTexture()
 	{
 		//just update some variables, not to create a real GL texture.
 		createGLTexture(mRawDiscardLevel, mRawImage, 0, FALSE);
-		mNeedsCreateTexture = FALSE;
+		mNeedsCreateTexture = false;
 		destroyRawImage();
 	}
 	else if(!force_update && getDiscardLevel() > -1 && getDiscardLevel() <= mRawDiscardLevel)
 	{
-		mNeedsCreateTexture = FALSE;
+		mNeedsCreateTexture = false;
 		destroyRawImage();
 	}
 	else
@@ -1441,7 +1441,7 @@ void LLViewerFetchedTexture::addToCreateTexture()
 						mRawDiscardLevel += i;
 						if(mRawDiscardLevel >= getDiscardLevel() && getDiscardLevel() > 0)
 						{
-							mNeedsCreateTexture = FALSE;
+							mNeedsCreateTexture = false;
 							destroyRawImage();
 							return;
 						}
@@ -1473,7 +1473,7 @@ BOOL LLViewerFetchedTexture::preCreateTexture(S32 usename/*= 0*/)
         destroyRawImage();
         return FALSE;
     }
-    mNeedsCreateTexture = FALSE;
+    mNeedsCreateTexture = false;
 
     if (mRawImage.isNull())
     {
@@ -1609,14 +1609,14 @@ void LLViewerFetchedTexture::postCreateTexture()
         destroyRawImage();
     }
 
-    mNeedsCreateTexture = FALSE;
+    mNeedsCreateTexture = false;
 }
 
 void LLViewerFetchedTexture::scheduleCreateTexture()
 {
     if (!mNeedsCreateTexture)
     {
-        mNeedsCreateTexture = TRUE;
+        mNeedsCreateTexture = true;
         if (preCreateTexture())
         {
 #if LL_IMAGEGL_THREAD_CHECK
@@ -1630,7 +1630,7 @@ void LLViewerFetchedTexture::scheduleCreateTexture()
                 memcpy(data_copy, data, size);
             }
 #endif
-            mNeedsCreateTexture = TRUE;
+            mNeedsCreateTexture = true;
             auto mainq = LLImageGLThread::sEnabled ? mMainQueue.lock() : nullptr;
             if (mainq)
             {
diff --git a/indra/newview/llviewertexture.h b/indra/newview/llviewertexture.h
index b953d7006b..2f5e0d01df 100644
--- a/indra/newview/llviewertexture.h
+++ b/indra/newview/llviewertexture.h
@@ -27,6 +27,7 @@
 #ifndef LL_LLVIEWERTEXTURE_H					
 #define LL_LLVIEWERTEXTURE_H
 
+#include "llatomic.h"
 #include "llgltexture.h"
 #include "lltimer.h"
 #include "llframetimer.h"
@@ -528,7 +529,9 @@ protected:
 	LLFrameTimer mStopFetchingTimer;	// Time since mDecodePriority == 0.f.
 
 	BOOL  mInImageList;				// TRUE if image is in list (in which case don't reset priority!)
-	BOOL  mNeedsCreateTexture;	
+	// This needs to be atomic, since it is written both in the main thread
+	// and in the GL image worker thread... HB
+	LLAtomicBool  mNeedsCreateTexture;	
 
 	BOOL   mForSculpt ; //a flag if the texture is used as sculpt data.
 	BOOL   mIsFetched ; //is loaded from remote or from cache, not generated locally.