| package aurelienribon.tweenengine.paths; |
| |
| import aurelienribon.tweenengine.TweenPath; |
| |
| /** |
| * @author Aurelien Ribon | http://www.aurelienribon.com/ |
| */ |
| public class CatmullRom implements TweenPath { |
| @Override |
| public float compute(float t, float[] points, int pointsCnt) { |
| int segment = (int) Math.floor((pointsCnt-1) * t); |
| segment = Math.max(segment, 0); |
| segment = Math.min(segment, pointsCnt-2); |
| |
| t = t * (pointsCnt-1) - segment; |
| |
| if (segment == 0) { |
| return catmullRomSpline(points[0], points[0], points[1], points[2], t); |
| } |
| |
| if (segment == pointsCnt-2) { |
| return catmullRomSpline(points[pointsCnt-3], points[pointsCnt-2], points[pointsCnt-1], points[pointsCnt-1], t); |
| } |
| |
| return catmullRomSpline(points[segment-1], points[segment], points[segment+1], points[segment+2], t); |
| } |
| |
| private float catmullRomSpline(float a, float b, float c, float d, float t) { |
| float t1 = (c - a) * 0.5f; |
| float t2 = (d - b) * 0.5f; |
| |
| float h1 = +2 * t * t * t - 3 * t * t + 1; |
| float h2 = -2 * t * t * t + 3 * t * t; |
| float h3 = t * t * t - 2 * t * t + t; |
| float h4 = t * t * t - t * t; |
| |
| return b * h1 + c * h2 + t1 * h3 + t2 * h4; |
| } |
| } |