From 91fe50ecc7f6e2c38286a456f2cb795fbcc92dd8 Mon Sep 17 00:00:00 2001
From: Dave Parks <davep@lindenlab.com>
Date: Thu, 9 Jun 2011 17:03:53 -0500
Subject: SH-1802 Fix for disappearing meshes under some circuimstances.

---
 indra/llmath/llvolume.cpp | 22 +++++++++++++++-------
 indra/newview/llface.cpp  | 31 +++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 7 deletions(-)

diff --git a/indra/llmath/llvolume.cpp b/indra/llmath/llvolume.cpp
index 379ef4b344..8c81f27784 100644
--- a/indra/llmath/llvolume.cpp
+++ b/indra/llmath/llvolume.cpp
@@ -2642,14 +2642,20 @@ bool LLVolume::unpackVolumeFaces(std::istream& is, S32 size)
 			LLVector4a& min = face.mExtents[0];
 			LLVector4a& max = face.mExtents[1];
 
-			min.clear();
-			max.clear();
-			min = max = face.mPositions[0];
-
-			for (S32 i = 1; i < face.mNumVertices; ++i)
+			if (face.mNumVertices < 3)
+			{ //empty face, use a dummy 1cm (at 1m scale) bounding box
+				min.splat(-0.005f);
+				max.splat(0.005f);
+			}
+			else
 			{
-				min.setMin(min, face.mPositions[i]);
-				max.setMax(max, face.mPositions[i]);
+				min = max = face.mPositions[0];
+
+				for (S32 i = 1; i < face.mNumVertices; ++i)
+				{
+					min.setMin(min, face.mPositions[i]);
+					max.setMax(max, face.mPositions[i]);
+				}
 			}
 		}
 	}
@@ -5506,6 +5512,8 @@ LLVolumeFace::LLVolumeFace() :
 	mOctree(NULL)
 {
 	mExtents = (LLVector4a*) ll_aligned_malloc_16(sizeof(LLVector4a)*3);
+	mExtents[0].splat(-0.5f);
+	mExtents[1].splat(0.5f);
 	mCenter = mExtents+2;
 }
 
diff --git a/indra/newview/llface.cpp b/indra/newview/llface.cpp
index 540ed054e9..b6566fcbd0 100644
--- a/indra/newview/llface.cpp
+++ b/indra/newview/llface.cpp
@@ -693,6 +693,19 @@ static void xform(LLVector2 &tex_coord, F32 cosAng, F32 sinAng, F32 offS, F32 of
 }
 
 
+bool less_than_max_mag(const LLVector4a& vec)
+{
+	LLVector4a MAX_MAG;
+	MAX_MAG.splat(1024.f*1024.f);
+
+	LLVector4a val;
+	val.setAbs(vec);
+
+	S32 lt = val.lessThan(MAX_MAG).getGatheredBits() & 0x7;
+	
+	return lt == 0x7;
+}
+
 BOOL LLFace::genVolumeBBoxes(const LLVolume &volume, S32 f,
 								const LLMatrix4& mat_vert_in, const LLMatrix3& mat_normal_in, BOOL global_volume)
 {
@@ -727,6 +740,8 @@ BOOL LLFace::genVolumeBBoxes(const LLVolume &volume, S32 f,
 		min = face.mExtents[0];
 		max = face.mExtents[1];
 		
+		llassert(less_than_max_mag(min));
+		llassert(less_than_max_mag(max));
 
 		//min, max are in volume space, convert to drawable render space
 		LLVector4a center;
@@ -738,6 +753,9 @@ BOOL LLFace::genVolumeBBoxes(const LLVolume &volume, S32 f,
 		size.setSub(max, min);
 		size.mul(0.5f);
 
+		llassert(less_than_max_mag(min));
+		llassert(less_than_max_mag(max));
+
 		if (!global_volume)
 		{
 			//VECTORIZE THIS
@@ -775,6 +793,8 @@ BOOL LLFace::genVolumeBBoxes(const LLVolume &volume, S32 f,
 		
 		newMin = newMax = center;
 		
+		llassert(less_than_max_mag(center));
+		
 		for (U32 i = 0; i < 4; i++)
 		{
 			LLVector4a delta;
@@ -786,6 +806,9 @@ BOOL LLFace::genVolumeBBoxes(const LLVolume &volume, S32 f,
 
 			newMin.setMin(newMin,min);
 			newMax.setMax(newMax,max);
+
+			llassert(less_than_max_mag(newMin));
+			llassert(less_than_max_mag(newMax));
 		}
 
 		if (!mDrawablep->isActive())
@@ -794,14 +817,22 @@ BOOL LLFace::genVolumeBBoxes(const LLVolume &volume, S32 f,
 			offset.load3(mDrawablep->getRegion()->getOriginAgent().mV);
 			newMin.add(offset);
 			newMax.add(offset);
+			
+			llassert(less_than_max_mag(newMin));
+			llassert(less_than_max_mag(newMax));
 		}
 
 		t.setAdd(newMin, newMax);
 		t.mul(0.5f);
 
+		llassert(less_than_max_mag(t));
+		
 		//VECTORIZE THIS
 		mCenterLocal.set(t.getF32ptr());
 		
+		llassert(less_than_max_mag(newMin));
+		llassert(less_than_max_mag(newMax));
+
 		t.setSub(newMax,newMin);
 		mBoundingSphereRadius = t.getLength3().getF32()*0.5f;
 
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