1/**
2 * Copyright (c) 2011, Novyon Events
3 *
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * - Redistributions of source code must retain the above copyright notice, this
10 * list of conditions and the following disclaimer.
11 *
12 * - Redistributions in binary form must reproduce the above copyright notice,
13 * this list of conditions and the following disclaimer in the documentation
14 * and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
25 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
26 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * @author Anthyon
29 */
30package com.jme3.terrain.noise.filter;
31
32import java.nio.FloatBuffer;
33import java.util.logging.Logger;
34
35import com.jme3.terrain.noise.ShaderUtils;
36import com.jme3.terrain.noise.fractal.FractalSum;
37
38public class PerturbFilter extends AbstractFilter {
39
40	private float magnitude;
41
42	@Override
43	public int getMargin(int size, int margin) {
44		margin = super.getMargin(size, margin);
45		return (int) Math.floor(this.magnitude * (margin + size) + margin);
46	}
47
48	public void setMagnitude(float magnitude) {
49		this.magnitude = magnitude;
50	}
51
52	public float getMagnitude() {
53		return this.magnitude;
54	}
55
56	@Override
57	public FloatBuffer filter(float sx, float sy, float base, FloatBuffer data, int workSize) {
58		float[] arr = data.array();
59		int origSize = (int) Math.ceil(workSize / (2 * this.magnitude + 1));
60		int offset = (workSize - origSize) / 2;
61		Logger.getLogger(PerturbFilter.class.getCanonicalName()).info(
62				"Found origSize : " + origSize + " and offset: " + offset + " for workSize : " + workSize + " and magnitude : "
63						+ this.magnitude);
64		float[] retval = new float[workSize * workSize];
65		float[] perturbx = new FractalSum().setOctaves(8).setScale(5f).getBuffer(sx, sy, base, workSize).array();
66		float[] perturby = new FractalSum().setOctaves(8).setScale(5f).getBuffer(sx, sy, base + 1, workSize).array();
67		for (int y = 0; y < workSize; y++) {
68			for (int x = 0; x < workSize; x++) {
69				// Perturb our coordinates
70				float noisex = perturbx[y * workSize + x];
71				float noisey = perturby[y * workSize + x];
72
73				int px = (int) (origSize * noisex * this.magnitude);
74				int py = (int) (origSize * noisey * this.magnitude);
75
76				float c00 = arr[this.wrap(y - py, workSize) * workSize + this.wrap(x - px, workSize)];
77				float c01 = arr[this.wrap(y - py, workSize) * workSize + this.wrap(x + px, workSize)];
78				float c10 = arr[this.wrap(y + py, workSize) * workSize + this.wrap(x - px, workSize)];
79				float c11 = arr[this.wrap(y + py, workSize) * workSize + this.wrap(x + px, workSize)];
80
81				float c0 = ShaderUtils.mix(c00, c01, noisex);
82				float c1 = ShaderUtils.mix(c10, c11, noisex);
83				retval[y * workSize + x] = ShaderUtils.mix(c0, c1, noisey);
84			}
85		}
86		return FloatBuffer.wrap(retval);
87	}
88
89	private int wrap(int v, int size) {
90		if (v < 0) {
91			return v + size - 1;
92		} else if (v >= size) {
93			return v - size;
94		} else {
95			return v;
96		}
97	}
98}
99