Be super sure not to let rigged vert weights extend beyond actual joint count.

indra/llrender/llshadermgr.cpp

@@ -1225,6 +1225,7 @@ void LLShaderMgr::initAttribsAndUniforms()
 
 	mReservedUniforms.push_back("matrixPalette");
 	mReservedUniforms.push_back("translationPalette");
+	mReservedUniforms.push_back("maxWeight");
 	
 	mReservedUniforms.push_back("screenTex");
 	mReservedUniforms.push_back("screenDepth");

indra/llrender/llshadermgr.h

@@ -179,6 +179,7 @@ public:
 		
 		AVATAR_MATRIX,
 		AVATAR_TRANSLATION,
+		AVATAR_MAX_WEIGHT,
 
 		WATER_SCREENTEX,
 		WATER_SCREENDEPTH,

indra/newview/app_settings/shaders/class1/avatar/objectSkinV.glsl

@@ -26,6 +26,7 @@ ATTRIBUTE vec4 weight4;
 
 uniform mat3 matrixPalette[52];
 uniform vec3 translationPalette[52];
+uniform float maxWeight;
 
 mat4 getObjectSkinnedTransform()
 {
@@ -34,7 +35,7 @@ mat4 getObjectSkinnedTransform()
 	vec4 w = fract(weight4);
 	vec4 index = floor(weight4);
 	
-		 index = min(index, vec4(51.0));
+		 index = min(index, vec4(maxWeight));
 		 index = max(index, vec4( 0.0));
 
 	float scale = 1.0/(w.x+w.y+w.z+w.w);

indra/newview/lldrawpoolavatar.cpp

@@ -1599,7 +1599,7 @@ void LLDrawPoolAvatar::updateRiggedFaceVertexBuffer(LLVOAvatar* avatar, LLFace*
 			{
 				F32 w = weight[j][k];
 
-				idx[k] = llclamp((S32) floorf(w), 0, 63);
+				idx[k] = llclamp((S32) floorf(w), 0, S32(count-1));
 				wght[k] = w - floorf(w);
 				scale += wght[k];
 			}
@@ -1747,7 +1747,7 @@ void LLDrawPoolAvatar::renderRigged(LLVOAvatar* avatar, U32 type, bool glow)
 					(GLfloat*) mp);
 
 				LLDrawPoolAvatar::sVertexProgram->uniform3fv(LLShaderMgr::AVATAR_TRANSLATION, count, transp);
-
+				LLDrawPoolAvatar::sVertexProgram->uniform1f(LLShaderMgr::AVATAR_MAX_WEIGHT, F32(count-1));
 				
 				stop_glerror();
 			}