improved robustness of penetrations involving triangles and boxes, by adding their 'preferred' penetration directions.

added wireframe/solid mode for meshes
updated solid penetration depth solver (comparison in Extras)

src/BulletCollision/CollisionShapes/btTriangleShape.h

@@ -157,6 +157,18 @@ public:
 			return "Triangle";
 		}
 
+		virtual int		getNumPreferredPenetrationDirections() const
+		{
+			return 2;
+		}
+		
+		virtual void	getPreferredPenetrationDirection(int index, btVector3& penetrationVector) const
+		{
+			calcNormal(penetrationVector);
+			if (index)
+				penetrationVector *= -1.f;
+		}
+
 
 };