diff --git a/src/Bullet3OpenCL/NarrowphaseCollision/kernels/sat.cl b/src/Bullet3OpenCL/NarrowphaseCollision/kernels/sat.cl
index 18626232c..8f517eb1f 100644
--- a/src/Bullet3OpenCL/NarrowphaseCollision/kernels/sat.cl
+++ b/src/Bullet3OpenCL/NarrowphaseCollision/kernels/sat.cl
@@ -1539,7 +1539,7 @@ inline int	findClippingFaces(const float4 separatingNormal,
 	int numWorldVertsB1= 0;
     
     
-	int closestFaceB=-1;
+	int closestFaceB=0;
 	float dmax = -FLT_MAX;
     
 	{
@@ -1573,7 +1573,7 @@ inline int	findClippingFaces(const float4 separatingNormal,
 		}
 	}
     
-    int closestFaceA=-1;
+    int closestFaceA=0;
 	{
 		float dmin = FLT_MAX;
 		for(int face=0;face<hullA->m_numFaces;face++)
diff --git a/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satConcave.cl b/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satConcave.cl
index 08876460e..aad795a64 100644
--- a/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satConcave.cl
+++ b/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satConcave.cl
@@ -597,7 +597,7 @@ inline int	findClippingFaces(const float4 separatingNormal,
 	int numWorldVertsB1= 0;
     
     
-	int closestFaceB=-1;
+	int closestFaceB=0;
 	float dmax = -FLT_MAX;
     
 	{
@@ -620,6 +620,8 @@ inline int	findClippingFaces(const float4 separatingNormal,
 		int numVertices = polyB.m_numIndices;
         if (numVertices>capacityWorldVerts)
             numVertices = capacityWorldVerts;
+        if (numVertices<0)
+            numVertices = 0;
         
 		for(int e0=0;e0<numVertices;e0++)
 		{
@@ -631,7 +633,7 @@ inline int	findClippingFaces(const float4 separatingNormal,
 		}
 	}
     
-    int closestFaceA=-1;
+    int closestFaceA=0;
 	{
 		float dmin = FLT_MAX;
 		for(int face=0;face<hullA->m_numFaces;face++)
@@ -656,6 +658,8 @@ inline int	findClippingFaces(const float4 separatingNormal,
     int numVerticesA = facesA[hullA->m_faceOffset+closestFaceA].m_numIndices;
     if (numVerticesA>capacityWorldVerts)
        numVerticesA = capacityWorldVerts;
+    if (numVerticesA<0)
+        numVerticesA=0;
     
 	for(int e0=0;e0<numVerticesA;e0++)
 	{
@@ -1179,6 +1183,7 @@ __kernel void   findConcaveSeparatingAxisEdgeEdgeKernel( __global int4* concaveP
  	float minDist = -1e30f;
 			float maxDist = 0.02f;
 
+            
             findClippingFaces(sepAxis,
                               &convexPolyhedronA,
                               &convexShapes[shapeIndexB],
diff --git a/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satConcaveKernels.h b/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satConcaveKernels.h
index 9c8389a2f..a9a751cb7 100644
--- a/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satConcaveKernels.h
+++ b/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satConcaveKernels.h
@@ -809,7 +809,7 @@ static const char* satConcaveKernelsCL= \
 "	int numWorldVertsB1= 0;\n"
 "    \n"
 "    \n"
-"	int closestFaceB=-1;\n"
+"	int closestFaceB=0;\n"
 "	float dmax = -FLT_MAX;\n"
 "    \n"
 "	{\n"
@@ -832,6 +832,8 @@ static const char* satConcaveKernelsCL= \
 "		int numVertices = polyB.m_numIndices;\n"
 "        if (numVertices>capacityWorldVerts)\n"
 "            numVertices = capacityWorldVerts;\n"
+"        if (numVertices<0)\n"
+"            numVertices = 0;\n"
 "        \n"
 "		for(int e0=0;e0<numVertices;e0++)\n"
 "		{\n"
@@ -843,7 +845,7 @@ static const char* satConcaveKernelsCL= \
 "		}\n"
 "	}\n"
 "    \n"
-"    int closestFaceA=-1;\n"
+"    int closestFaceA=0;\n"
 "	{\n"
 "		float dmin = FLT_MAX;\n"
 "		for(int face=0;face<hullA->m_numFaces;face++)\n"
@@ -868,6 +870,8 @@ static const char* satConcaveKernelsCL= \
 "    int numVerticesA = facesA[hullA->m_faceOffset+closestFaceA].m_numIndices;\n"
 "    if (numVerticesA>capacityWorldVerts)\n"
 "       numVerticesA = capacityWorldVerts;\n"
+"    if (numVerticesA<0)\n"
+"        numVerticesA=0;\n"
 "    \n"
 "	for(int e0=0;e0<numVerticesA;e0++)\n"
 "	{\n"
@@ -1382,6 +1386,7 @@ static const char* satConcaveKernelsCL= \
 "           \n"
 " 	float minDist = -1e30f;\n"
 "			float maxDist = 0.02f;\n"
+"            \n"
 "            findClippingFaces(sepAxis,\n"
 "                              &convexPolyhedronA,\n"
 "                              &convexShapes[shapeIndexB],\n"
diff --git a/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satKernels.h b/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satKernels.h
index a55ccea35..b4a96188c 100644
--- a/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satKernels.h
+++ b/src/Bullet3OpenCL/NarrowphaseCollision/kernels/satKernels.h
@@ -1642,7 +1642,7 @@ static const char* satKernelsCL= \
 "	int numWorldVertsB1= 0;\n"
 "    \n"
 "    \n"
-"	int closestFaceB=-1;\n"
+"	int closestFaceB=0;\n"
 "	float dmax = -FLT_MAX;\n"
 "    \n"
 "	{\n"
@@ -1676,7 +1676,7 @@ static const char* satKernelsCL= \
 "		}\n"
 "	}\n"
 "    \n"
-"    int closestFaceA=-1;\n"
+"    int closestFaceA=0;\n"
 "	{\n"
 "		float dmin = FLT_MAX;\n"
 "		for(int face=0;face<hullA->m_numFaces;face++)\n"