/*
* @(#)SplineInterpolator.java 1.0 September 9, 2007
*
* Copyright (c) 2011 Werner Randelshofer
* Hausmatt 10, CH-6405 Goldau, Switzerland
* All rights reserved.
*
* The copyright of this software is owned by Werner Randelshofer.
* You may not use, copy or modify this software, except in
* accordance with the license agreement you entered into with
* Werner Randelshofer. For details see accompanying license terms.
*/
package org.monte.media;
import java.awt.geom.Point2D;
import java.util.Arrays;
/**
* A bezier interpolator for use in conjunction with an Animator object.
* <p>
* This class interpolates fractional values using a Bezier spline. The anchor
* points for the spline are assumed to be (0, 0) and (1, 1). Control points
* should all be in the range [0, 1].
* <p>
* FIXME - This interpolator does not work!
*
* @author Werner Randelshofer
* @version $Id: BezierInterpolator.java 299 2013-01-03 07:40:18Z werner $
*/
public class BezierInterpolator extends AbstractSplineInterpolator {
/** Note: (x0,y0) and (x1,y1) are implicitly (0, 0) and (1,1) respectively. */
private double[] controlPoints;
/**
* Creates a new instance of SplineInterpolator with the control points
* defined by (x1, y1) and (x2, y2). The anchor points are implicitly
* defined as (0, 0) and (1, 1).
* <p>
* The interpolator runs for one second.
* </p>
*
* @param x1 The x coordinate for the first bezier control point.
* @param y1 The y coordinate for the first bezier control point.
* @param x2 The x coordinate for the second bezier control point.
* @param y2 The x coordinate for the second bezier control point.
*
* @throws IllegalArgumentException This exception is thrown when values
* beyond the allowed [0,1] range are passed in
*/
public BezierInterpolator(float x1, float y1, float x2, float y2) {
this(x1, y1, x2, y2, 1000);
}
/**
* Creates a new instance of SplineInterpolator with the control points
* defined by (x1, y1) and (x2, y2). The anchor points are implicitly
* defined as (0, 0) and (1, 1).
* <p>
* The interpolator runs for the specified time span.
* </p>
* @param x1 The x coordinate for the first bezier control point.
* @param y1 The y coordinate for the first bezier control point.
* @param x2 The x coordinate for the second bezier control point.
* @param y2 The x coordinate for the second bezier control point.
* @param timespan The time span in milliseconds.
*
*
* @throws IllegalArgumentException This exception is thrown when values
* beyond the allowed [0,1] range are passed in
*/
public BezierInterpolator(float x1, float y1, float x2, float y2, long timespan) {
this(x1, y1, x2, y2, false, timespan);
}
/**
* Creates a new instance of SplineInterpolator with the control points
* defined by (x1, y1) and (x2, y2). The anchor points are implicitly
* defined as (0, 0) and (1, 1).
* <p>
* The interpolator runs for the specified time span.
* </p>
* @param x1 The x coordinate for the first bezier control point.
* @param y1 The y coordinate for the first bezier control point.
* @param x2 The x coordinate for the second bezier control point.
* @param y2 The x coordinate for the second bezier control point.
* @param reverse Run interpolator in the reverse direction.
* @param timespan The time span in milliseconds.
*
*
* @throws IllegalArgumentException This exception is thrown when values
* beyond the allowed [0,1] range are passed in
*/
public BezierInterpolator(float x1, float y1, float x2, float y2, boolean reverse, long timespan) {
super((reverse) ? 1f : 0f, (reverse) ? 0f : 1f, timespan);
if (x1 < 0 || x1 > 1.0f
|| y1 < 0 || y1 > 1.0f
|| x2 < 0 || x2 > 1.0f
|| y2 < 0 || y2 > 1.0f) {
throw new IllegalArgumentException("Control points must be in "
+ "the range [0, 1]:");
}
controlPoints=new double[4*2];
controlPoints[0] = 0;
controlPoints[1] = 0;
controlPoints[2] = x1;
controlPoints[3] = y1;
controlPoints[4] = x2;
controlPoints[5] = y2;
controlPoints[6] = 1;
controlPoints[7] = 1;
updateFractions(100);
}
/** Interpolates between the specified control points.
*
* @param controlPoints The control points of the bezier path. Must include
* the first and the last control point. The curve must be in the range [0,1].
*
*/
public BezierInterpolator(double[][] controlPoints) {
this(controlPoints,false,1000);
}
/** Interpolates between the specified control points.
*
* @param controlPoints The control points of the bezier path. Must include
* the first and the last control point. The curve must be in the range [0,1].
*
*/
public BezierInterpolator(double[][] controlPoints, boolean reverse, long timespan) {
super((reverse) ? 1f : 0f, (reverse) ? 0f : 1f, timespan);
this.controlPoints=new double[controlPoints.length*2];
for (int i=0;i<controlPoints.length;i++){
this.controlPoints[i*2]=controlPoints[i][0];
this.controlPoints[i*2+1]=controlPoints[i][1];
}
updateFractions(100);
}
/**
* Evaluates the bezier function and returns a 2D point.
* @return A point, with x- and y-coordinates for time t.
*/
@Override
public Point2D.Float getXY(float t, Point2D.Float xy) {
if (xy==null)xy=new Point2D.Float(0,0);
double[] p = controlPoints.clone();
for (int i = p.length/2-1; i > 0; i--) {
for (int j = 0; j < i; j++) {
p[j*2+0] = (1 - t) * p[j*2+0] + t * p[(j+1)*2+0];
p[j*2+1] = (1 - t) * p[j*2+1] + t * p[(j + 1)*2+1];
}
}
xy.setLocation(p[0],p[1]);
return xy;
}
/**
* Evaluates the bezier function and returns a 2D point.
* @return A point, with x- and y-coordinates for time t.
*/
@Override
public float getY(float t) {
double[] p = controlPoints.clone();
for (int i = p.length/2-1; i > 0; i--) {
for (int j = 0; j < i; j++) {
p[j*2+0] = (1 - t) * p[j*2+0] + t * p[(j + 1)*2+0];
p[j*2+1] = (1 - t) * p[j*2+1] + t * p[(j + 1)*2+1];
}
}
return (float)p[1];
}
}