Draw a skin sprite with curved edges.
|n||Number of segments|
|cxB||X of control point on bottom edge|
|cyB||Y of control point on bottom edge|
|cxT||X of control point on top edge|
|cyT||Y of control point on top edge|
Points are in the order of bottom-left, top-left, top-right, bottom-right.
Bézier curves are drawn on the curved edges with respective vertexes and control point.
Curved edges are drawn in segments. The bigger the number of segments, the smoother the curve, and the costlier the drawing.