fixes crash related to empty concavecollisionshape, fixes #1709

servers/physics/shape_sw.cpp

@@ -997,6 +997,11 @@ DVector<Vector3> ConcavePolygonShapeSW::get_faces() const {
 void ConcavePolygonShapeSW::project_range(const Vector3& p_normal, const Transform& p_transform, real_t &r_min, real_t &r_max) const {
 
 	int count=vertices.size();
+	if (count==0) {
+		r_min=0;
+		r_max=0;
+		return;
+	}
 	DVector<Vector3>::Read r=vertices.read();
 	const Vector3 *vptr=r.ptr();
 
@@ -1016,6 +1021,9 @@ Vector3 ConcavePolygonShapeSW::get_support(const Vector3& p_normal) const {
 
 
 	int count=vertices.size();
+	if (count==0)
+		return Vector3();
+
 	DVector<Vector3>::Read r=vertices.read();
 	const Vector3 *vptr=r.ptr();
 
@@ -1103,6 +1111,9 @@ void ConcavePolygonShapeSW::_cull_segment(int p_idx,_SegmentCullParams *p_params
 
 bool ConcavePolygonShapeSW::intersect_segment(const Vector3& p_begin,const Vector3& p_end,Vector3 &r_result, Vector3 &r_normal) const {
 
+	if (faces.size()==0)
+		return false;
+
 	// unlock data
 	DVector<Face>::Read fr=faces.read();
 	DVector<Vector3>::Read vr=vertices.read();
@@ -1171,6 +1182,8 @@ void ConcavePolygonShapeSW::_cull(int p_idx,_CullParams *p_params) const {
 void ConcavePolygonShapeSW::cull(const AABB& p_local_aabb,Callback p_callback,void* p_userdata) const {
 
 	// make matrix local to concave
+	if (faces.size()==0)
+		return;
 
 	AABB local_aabb=p_local_aabb;