3 files changed, 33 insertions, 9 deletions
diff --git a/indra/newview/llspatialpartition.cpp b/indra/newview/llspatialpartition.cpp
index 38c7dd8283..1ded126bee 100644
--- a/indra/newview/llspatialpartition.cpp
+++ b/indra/newview/llspatialpartition.cpp
@@ -1465,10 +1465,14 @@ void LLSpatialGroup::handleChildRemoval(const OctreeNode* parent, const OctreeNo
 	unbound();
 }
 
-void LLSpatialGroup::destroyGL() 
+void LLSpatialGroup::destroyGL(bool keep_occlusion) 
 {
 	setState(LLSpatialGroup::GEOM_DIRTY | LLSpatialGroup::IMAGE_DIRTY);
-	gPipeline.markRebuild(this, TRUE);
+
+	if (!keep_occlusion)
+	{ //going to need a rebuild
+		gPipeline.markRebuild(this, TRUE);
+	}
 
 	mLastUpdateTime = gFrameTimeSeconds;
 	mVertexBuffer = NULL;
@@ -1476,16 +1480,20 @@ void LLSpatialGroup::destroyGL()
 
 	clearDrawMap();
 
-	for (U32 i = 0; i < LLViewerCamera::NUM_CAMERAS; i++)
+	if (!keep_occlusion)
 	{
-		if (mOcclusionQuery[i])
+		for (U32 i = 0; i < LLViewerCamera::NUM_CAMERAS; i++)
 		{
-			sQueryPool.release(mOcclusionQuery[i]);
-			mOcclusionQuery[i] = 0;
+			if (mOcclusionQuery[i])
+			{
+				sQueryPool.release(mOcclusionQuery[i]);
+				mOcclusionQuery[i] = 0;
+			}
 		}
+
+		mOcclusionVerts = NULL;
 	}
 
-	mOcclusionVerts = NULL;
 
 	for (LLSpatialGroup::element_iter i = getData().begin(); i != getData().end(); ++i)
 	{
@@ -1635,7 +1643,9 @@ void LLSpatialGroup::checkOcclusion()
 				else
 				{
 					assert_states_valid(this);
+					
 					setOcclusionState(LLSpatialGroup::OCCLUDED, LLSpatialGroup::STATE_MODE_DIFF);
+					
 					assert_states_valid(this);
 				}
 
diff --git a/indra/newview/llspatialpartition.h b/indra/newview/llspatialpartition.h
index 1a93145cc5..ccc65f3da0 100644
--- a/indra/newview/llspatialpartition.h
+++ b/indra/newview/llspatialpartition.h
@@ -316,7 +316,7 @@ public:
 	void buildOcclusion(); //rebuild mOcclusionVerts
 	void checkOcclusion(); //read back last occlusion query (if any)
 	void doOcclusion(LLCamera* camera); //issue occlusion query
-	void destroyGL();
+	void destroyGL(bool keep_occlusion = false);
 	
 	void updateDistance(LLCamera& camera);
 	BOOL needsUpdate();
diff --git a/indra/newview/llvovolume.cpp b/indra/newview/llvovolume.cpp
index 16b61496a6..f656e61cca 100644
--- a/indra/newview/llvovolume.cpp
+++ b/indra/newview/llvovolume.cpp
@@ -682,7 +682,21 @@ void LLVOVolume::updateTextures()
 	const F32 TEXTURE_AREA_REFRESH_TIME = 5.f; // seconds
 	if (mTextureUpdateTimer.getElapsedTimeF32() > TEXTURE_AREA_REFRESH_TIME)
 	{
-		updateTextureVirtualSize();		
+		updateTextureVirtualSize();
+
+		if (mDrawable.notNull() && !isVisible())
+		{ //delete vertex buffer to free up some VRAM
+			LLSpatialGroup* group  = mDrawable->getSpatialGroup();
+			if (group)
+			{
+				group->destroyGL(true);
+
+				//flag the group as having changed draw info state so it gets a rebuild next time
+				//it becomes visible
+				group->setState(LLSpatialGroup::NEW_DRAWINFO);
+			}
+		}
+
 	}
 }