fix for issue 1400

use default output name for VHACD test binary

Extras/VHACD/test/src/main.cpp

@@ -38,6 +38,14 @@
 using namespace VHACD;
 using namespace std;
 
+bool replace(std::string& str, const std::string& from, const std::string& to) {
+    size_t start_pos = str.find(from);
+    if(start_pos == std::string::npos)
+        return false;
+    str.replace(start_pos, from.length(), to);
+    return true;
+}
+
 class MyCallback : public IVHACD::IUserCallback {
 public:
     MyCallback(void) {}
@@ -293,7 +301,16 @@ void ParseParameters(int argc, char* argv[], Parameters& params)
     for (int i = 1; i < argc; ++i) {
         if (!strcmp(argv[i], "--input")) {
             if (++i < argc)
+		{
                 params.m_fileNameIn = argv[i];
+		//come up with some default output name, if not provided
+		if (params.m_fileNameOut.length()==0)
+		{
+                	string tmp = argv[i];
+			replace(tmp,".obj",".vhacd.obj");
+			params.m_fileNameOut = tmp;
+		}
+		}
         }
         else if (!strcmp(argv[i], "--output")) {
             if (++i < argc)

src/BulletDynamics/Vehicle/btRaycastVehicle.cpp

@@ -615,7 +615,7 @@ void	btRaycastVehicle::updateFriction(btScalar	timeStep)
 					btScalar defaultRollingFrictionImpulse = 0.f;
 					btScalar maxImpulse = wheelInfo.m_brake ? wheelInfo.m_brake : defaultRollingFrictionImpulse;
 					btWheelContactPoint contactPt(m_chassisBody,groundObject,wheelInfo.m_raycastInfo.m_contactPointWS,m_forwardWS[wheel],maxImpulse);
-					rollingFriction = calcRollingFriction(contactPt);
+					rollingFriction = calcRollingFriction(contactPt)/btScalar(getNumWheels());
 				}
 			}