Ejemplo n.º 1
0
        /**
         *      Rotates a shape 180 degrees around the edge shared by the two given points.
         *
         *      The two points must be neighbors.
         */
        public static IEnumerable <FlatHexPoint> Rotate180About(
            IEnumerable <FlatHexPoint> shape,
            FlatHexPoint p1,
            FlatHexPoint p2)
        {
            var translation = p1.Translate(p2);
            var correction  = translation.Subtract(translation.Rotate180()).ScaleDown(2);

            return(TransformShape <FlatHexPoint>(shape, point => point.Rotate180().Translate(correction)).ToList());
        }
Ejemplo n.º 2
0
        /**
         *      Rotates a shape 120 degrees around the vertice shared by the three given points.
         *
         *      The three points must form a close triangle (they must share a vertex).
         */
        public static IEnumerable <FlatHexPoint> Rotate120About(
            IEnumerable <FlatHexPoint> shape,
            FlatHexPoint p1,
            FlatHexPoint p2,
            FlatHexPoint p3)
        {
            /*
             *      If t = (p1 + p2 + p3)/3, then the result is p => (p - t).Rotate120() + t.
             *
             *      This can be rewritten p => p.Rotate120() - t.Rotate120() + t
             *      = p.Rotate120() (T - T.Rotate120())/3,
             *      where T = p1 + p2 + p3.
             *
             *      This is what this method calculates. This is done so that all coordinates in
             *      intermediatary calculations stay integers.
             */

            var translation = p1.Translate(p2.Translate(p3));
            var correction  = translation.Subtract(translation.Rotate120()).ScaleDown(3);

            return(TransformShape(shape, point => point.Rotate120().Translate(correction)).ToList());
        }