3 files changed, 17 insertions, 4 deletions
diff --git a/indra/newview/llmeshrepository.cpp b/indra/newview/llmeshrepository.cpp
index b772999ee2..edcf249a21 100755
--- a/indra/newview/llmeshrepository.cpp
+++ b/indra/newview/llmeshrepository.cpp
@@ -2160,7 +2160,7 @@ S32 LLMeshRepository::update()
 	return size ;
 }
 
-S32 LLMeshRepository::loadMesh(LLVOVolume* vobj, const LLVolumeParams& mesh_params, S32 detail)
+S32 LLMeshRepository::loadMesh(LLVOVolume* vobj, const LLVolumeParams& mesh_params, S32 detail, S32 last_lod)
 {
 	if (detail < 0 || detail > 4)
 	{
@@ -2201,7 +2201,19 @@ S32 LLMeshRepository::loadMesh(LLVOVolume* vobj, const LLVolumeParams& mesh_para
 
 		if (group)
 		{
-			//first see what the next lowest LOD available might be
+			//first, see if last_lod is available (don't transition down to avoid funny popping a la SH-641)
+			if (last_lod >= 0)
+			{
+				LLVolume* lod = group->refLOD(last_lod);
+				if (lod && !lod->isTetrahedron() && lod->getNumVolumeFaces() > 0)
+				{
+					group->derefLOD(lod);
+					return last_lod;
+				}
+				group->derefLOD(lod);
+			}
+
+			//next, see what the next lowest LOD available might be
 			for (S32 i = detail-1; i >= 0; --i)
 			{
 				LLVolume* lod = group->refLOD(i);
diff --git a/indra/newview/llmeshrepository.h b/indra/newview/llmeshrepository.h
index eccb82b661..b642a89192 100644
--- a/indra/newview/llmeshrepository.h
+++ b/indra/newview/llmeshrepository.h
@@ -456,7 +456,7 @@ public:
 	S32 update() ;
 
 	//mesh management functions
-	S32 loadMesh(LLVOVolume* volume, const LLVolumeParams& mesh_params, S32 detail = 0);
+	S32 loadMesh(LLVOVolume* volume, const LLVolumeParams& mesh_params, S32 detail = 0, S32 last_lod = -1);
 	
 	void notifyLoadedMeshes();
 	void notifyMeshLoaded(const LLVolumeParams& mesh_params, LLVolume* volume);
diff --git a/indra/newview/llvovolume.cpp b/indra/newview/llvovolume.cpp
index 3dc82f5368..b296d21b2b 100644
--- a/indra/newview/llvovolume.cpp
+++ b/indra/newview/llvovolume.cpp
@@ -936,6 +936,7 @@ BOOL LLVOVolume::setVolume(const LLVolumeParams &params_in, const S32 detail, bo
 {
 	LLVolumeParams volume_params = params_in;
 
+	S32 last_lod = mVolumep.notNull() ? LLVolumeLODGroup::getVolumeDetailFromScale(mVolumep->getDetail()) : -1;
 	S32 lod = mLOD;
 
 	BOOL is404 = FALSE;
@@ -1014,7 +1015,7 @@ BOOL LLVOVolume::setVolume(const LLVolumeParams &params_in, const S32 detail, bo
 				{ 
 					//load request not yet issued, request pipeline load this mesh
 					LLUUID asset_id = volume_params.getSculptID();
-					S32 available_lod = gMeshRepo.loadMesh(this, volume_params, lod);
+					S32 available_lod = gMeshRepo.loadMesh(this, volume_params, lod, last_lod);
 					if (available_lod != lod)
 					{
 						LLPrimitive::setVolume(volume_params, available_lod);