public void AddContour(ContourVertex[] vertices) { AddContour(vertices, ContourOrientation.Original); }
public void AddContour(ContourVertex[] vertices, ContourOrientation forceOrientation) { if (_mesh == null) { _mesh = new Mesh(); } bool reverse = false; if (forceOrientation != ContourOrientation.Original) { float area = SignedArea(vertices); reverse = (forceOrientation == ContourOrientation.Clockwise && area < 0.0f) || (forceOrientation == ContourOrientation.CounterClockwise && area > 0.0f); } MeshUtils.Edge e = null; for (int i = 0; i < vertices.Length; ++i) { if (e == null) { e = _mesh.MakeEdge(); _mesh.Splice(e, e._Sym); } else { // Create a new vertex and edge which immediately follow e // in the ordering around the left face. _mesh.SplitEdge(e); e = e._Lnext; } int index = reverse ? vertices.Length - 1 - i : i; // The new vertex is now e._Org. e._Org._coords = vertices [index].Position; e._Org._data = vertices [index].Data; // The winding of an edge says how the winding number changes as we // cross from the edge's right face to its left face. We add the // vertices in such an order that a CCW contour will add +1 to // the winding number of the region inside the contour. e._winding = 1; e._Sym._winding = -1; } }
private float SignedArea(ContourVertex[] vertices) { float area = 0.0f; for (int i = 0; i < vertices.Length; i++) { var v0 = vertices [i]; var v1 = vertices [(i + 1) % vertices.Length]; area += v0.Position.X * v1.Position.Y; area -= v0.Position.Y * v1.Position.X; } return area * 0.5f; }