diff options
| -rw-r--r-- | scene/resources/convex_polygon_shape_2d.cpp | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/scene/resources/convex_polygon_shape_2d.cpp b/scene/resources/convex_polygon_shape_2d.cpp index 7f19dd63e6..0d9e570149 100644 --- a/scene/resources/convex_polygon_shape_2d.cpp +++ b/scene/resources/convex_polygon_shape_2d.cpp @@ -38,11 +38,41 @@ bool ConvexPolygonShape2D::_edit_is_selected_on_click(const Point2 &p_point, dou return Geometry2D::is_point_in_polygon(p_point, points); } +#ifdef DEBUG_ENABLED +// Check if point p3 is to the left of [p1, p2] segment or on it. +bool left_test(const Vector2 &p1, const Vector2 &p2, const Vector2 &p3) { + Vector2 p12 = p2 - p1; + Vector2 p13 = p3 - p1; + // If the value of the cross product is positive or zero; p3 is to the left or on the segment, respectively. + return p12.cross(p13) >= 0; +} + +bool is_convex(const Vector<Vector2> &p_points) { + // Pre-condition: Polygon is in counter-clockwise order. + int polygon_size = p_points.size(); + for (int i = 0; i < polygon_size && polygon_size > 3; i++) { + int j = (i + 1) % polygon_size; + int k = (j + 1) % polygon_size; + // If any consecutive three points fail left-test, then there is a concavity. + if (!left_test(p_points[i], p_points[j], p_points[k])) { + return false; + } + } + + return true; +} +#endif + void ConvexPolygonShape2D::_update_shape() { Vector<Vector2> final_points = points; if (Geometry2D::is_polygon_clockwise(final_points)) { //needs to be counter clockwise final_points.reverse(); } +#ifdef DEBUG_ENABLED + if (!is_convex(final_points)) { + WARN_PRINT("Concave polygon is assigned to ConvexPolygonShape2D."); + } +#endif PhysicsServer2D::get_singleton()->shape_set_data(get_rid(), final_points); emit_changed(); } |