1 files changed, 22 insertions, 6 deletions

diff --git a/modules/csg/csg.cpp b/modules/csg/csg.cpp
index f399466fe5..c1fe11d6aa 100644
--- a/modules/csg/csg.cpp
+++ b/modules/csg/csg.cpp
@@ -409,6 +409,9 @@ void CSGBrushOperation::BuildPoly::clip(const CSGBrush *p_brush, int p_face, Mes
 
 	//transform A points to 2D
 
+	if (segment[0].distance_to(segment[1]) < CMP_EPSILON)
+		return; //too small
+
 	_clip_segment(p_brush, p_face, segment, mesh_merge, p_for_B);
 }
 
@@ -586,8 +589,6 @@ void CSGBrushOperation::_add_poly_points(const BuildPoly &p_poly, int p_edge, in
 		edge_stack.push_back(es);
 	}
 
-	int limit = p_poly.points.size() * 4;
-
 	//attempt to empty the stack.
 	while (edge_stack.size()) {
 
@@ -608,7 +609,9 @@ void CSGBrushOperation::_add_poly_points(const BuildPoly &p_poly, int p_edge, in
 
 		edge_process[e.edge] = true; //mark as processed
 
-		while (to_point != e.prev_point) {
+		int limit = p_poly.points.size() * 4; //avoid infinite recursion
+
+		while (to_point != e.prev_point && limit) {
 
 			Vector2 segment[2] = { p_poly.points[prev_point].point, p_poly.points[to_point].point };
 
@@ -618,6 +621,9 @@ void CSGBrushOperation::_add_poly_points(const BuildPoly &p_poly, int p_edge, in
 			t2d[1] = Vector2(-t2d[0].y, t2d[0].x); // use as tangent
 			t2d[2] = segment[1]; //origin
 
+			if (t2d.basis_determinant() == 0)
+				break; //abort poly
+
 			t2d.affine_invert();
 
 			//push all edges found here, they will be sorted by minimum angle later.
@@ -674,6 +680,8 @@ void CSGBrushOperation::_add_poly_points(const BuildPoly &p_poly, int p_edge, in
 			to_point = next_point;
 			edge_process[next_edge] = true; //mark this edge as processed
 			current_edge = next_edge;
+
+			limit--;
 		}
 
 		//if more than 2 points were added to the polygon, add it to the list of polygons.
@@ -696,7 +704,9 @@ void CSGBrushOperation::_add_poly_outline(const BuildPoly &p_poly, int p_from_po
 	int prev_point = p_from_point;
 	int to_point = p_to_point;
 
-	while (to_point != p_from_point) {
+	int limit = p_poly.points.size() * 4; //avoid infinite recursion
+
+	while (to_point != p_from_point && limit) {
 
 		Vector2 segment[2] = { p_poly.points[prev_point].point, p_poly.points[to_point].point };
 		//again create a transform to compute the angle.
@@ -704,6 +714,10 @@ void CSGBrushOperation::_add_poly_outline(const BuildPoly &p_poly, int p_from_po
 		t2d[0] = (segment[1] - segment[0]).normalized(); //use as Y
 		t2d[1] = Vector2(-t2d[0].y, t2d[0].x); // use as tangent
 		t2d[2] = segment[1]; //origin
+
+		if (t2d.basis_determinant() == 0)
+			break; //abort poly
+
 		t2d.affine_invert();
 
 		float max_angle;
@@ -731,6 +745,8 @@ void CSGBrushOperation::_add_poly_outline(const BuildPoly &p_poly, int p_from_po
 		r_outline.push_back(to_point);
 		prev_point = to_point;
 		to_point = next_point_angle;
+
+		limit--;
 	}
 }
 
@@ -1216,7 +1232,7 @@ void CSGBrushOperation::MeshMerge::mark_inside_faces() {
 		center /= 3.0;
 
 		Plane plane(points[faces[i].points[0]], points[faces[i].points[1]], points[faces[i].points[2]]);
-		Vector3 target = center + plane.normal * max_distance;
+		Vector3 target = center + plane.normal * max_distance + Vector3(0.0001234, 0.000512, 0.00013423); //reduce chance of edge hits by doing a small increment
 
 		int intersections = _bvh_count_intersections(bvh, max_depth, max_alloc - 1, center, target, i);
 
@@ -1239,7 +1255,7 @@ void CSGBrushOperation::MeshMerge::add_face(const Vector3 &p_a, const Vector3 &p
 		vk.z = int((double(src_points[i].z) + double(vertex_snap) * 0.31234) / double(vertex_snap));
 
 		int res;
-		if (snap_cache.lookup(vk, &res)) {
+		if (snap_cache.lookup(vk, res)) {
 			indices[i] = res;
 		} else {
 			indices[i] = points.size();