added preferred direction, to improve penetration depth quality (better matching collision normal) for triangle meshes.

Extras/BulletMultiThreaded/SpuNarrowPhaseCollisionTask/SpuMinkowskiPenetrationDepthSolver.cpp

@@ -17,6 +17,7 @@ subject to the following restrictions:
 #include "SpuVoronoiSimplexSolver.h"
 #include "SpuGjkPairDetector.h"
 #include "SpuContactResult.h"
+#include "SpuPreferredPenetrationDirections.h"
 
 
 #include "SpuLocalSupport.h"
@@ -200,15 +201,17 @@ bool SpuMinkowskiPenetrationDepthSolver::calcPenDepth( SpuVoronoiSimplexSolver&
 
 	int numSampleDirections = NUM_UNITSPHERE_POINTS;
 
+///this is necessary, otherwise the normal is not correct, and sphere will rotate forever on a sloped triangle mesh
+#define DO_PREFERRED_DIRECTIONS 1
 #ifdef DO_PREFERRED_DIRECTIONS
 	{
-		int numPDA = convexA->getNumPreferredPenetrationDirections();
+		int numPDA = spuGetNumPreferredPenetrationDirections(shapeTypeA,convexA);
 		if (numPDA)
 		{
 			for (int i=0;i<numPDA;i++)
 			{
 				btVector3 norm;
-				convexA->getPreferredPenetrationDirection(i,norm);
+				spuGetPreferredPenetrationDirection(shapeTypeA,convexA,i,norm);
 				norm  = transA.getBasis() * norm;
 				sPenetrationDirections[numSampleDirections] = norm;
 				numSampleDirections++;
@@ -217,13 +220,13 @@ bool SpuMinkowskiPenetrationDepthSolver::calcPenDepth( SpuVoronoiSimplexSolver&
 	}
 
 	{
-		int numPDB = convexB->getNumPreferredPenetrationDirections();
+		int numPDB = spuGetNumPreferredPenetrationDirections(shapeTypeB,convexB);
 		if (numPDB)
 		{
 			for (int i=0;i<numPDB;i++)
 			{
 				btVector3 norm;
-				convexB->getPreferredPenetrationDirection(i,norm);
+				spuGetPreferredPenetrationDirection(shapeTypeB,convexB,i,norm);
 				norm  = transB.getBasis() * norm;
 				sPenetrationDirections[numSampleDirections] = norm;
 				numSampleDirections++;

Extras/BulletMultiThreaded/SpuNarrowPhaseCollisionTask/SpuPreferredPenetrationDirections.h

@@ -0,0 +1,70 @@
+/*
+Bullet Continuous Collision Detection and Physics Library
+Copyright (c) 2003-2007 Erwin Coumans  http://continuousphysics.com/Bullet/
+
+This software is provided 'as-is', without any express or implied warranty.
+In no event will the authors be held liable for any damages arising from the use of this software.
+Permission is granted to anyone to use this software for any purpose, 
+including commercial applications, and to alter it and redistribute it freely, 
+subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef _SPU_PREFERRED_PENETRATION_DIRECTIONS_H
+#define _SPU_PREFERRED_PENETRATION_DIRECTIONS_H
+
+
+#include "BulletCollision/BroadphaseCollision/btBroadphaseProxy.h"
+
+int		spuGetNumPreferredPenetrationDirections(int shapeType, void* shape)
+{
+	switch (shapeType)
+    {
+		case TRIANGLE_SHAPE_PROXYTYPE:
+		{
+			return 2;
+			//spu_printf("2\n");
+			break;
+		}
+		default:
+			{
+#if __ASSERT
+        spu_printf("spuGetNumPreferredPenetrationDirections() - Unsupported bound type: %d.\n", shapeType);
+#endif // __ASSERT
+			}
+	}
+
+	return 0;	
+}	
+
+void	spuGetPreferredPenetrationDirection(int shapeType, void* shape, int index, btVector3& penetrationVector)
+{
+
+
+	switch (shapeType)
+    {
+		case TRIANGLE_SHAPE_PROXYTYPE:
+		{
+			btVector3* vertices = (btVector3*)shape;
+			///calcNormal
+			penetrationVector = (vertices[1]-vertices[0]).cross(vertices[2]-vertices[0]);
+			penetrationVector.normalize();
+			if (index)
+				penetrationVector *= btScalar(-1.);
+			break;
+		}
+		default:
+			{
+					
+#if __ASSERT
+        spu_printf("spuGetNumPreferredPenetrationDirections() - Unsupported bound type: %d.\n", shapeType);
+#endif // __ASSERT
+			}
+	}
+		
+}
+
+#endif //_SPU_PREFERRED_PENETRATION_DIRECTIONS_H