1/*
2 * Copyright (c) 2009-2012 jMonkeyEngine
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met:
8 *
9 * * Redistributions of source code must retain the above copyright
10 *   notice, this list of conditions and the following disclaimer.
11 *
12 * * Redistributions in binary form must reproduce the above copyright
13 *   notice, this list of conditions and the following disclaimer in the
14 *   documentation and/or other materials provided with the distribution.
15 *
16 * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
17 *   may be used to endorse or promote products derived from this software
18 *   without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
24 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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30 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33// $Id: PQTorus.java 4131 2009-03-19 20:15:28Z blaine.dev $
34package com.jme3.scene.shape;
35
36import com.jme3.export.InputCapsule;
37import com.jme3.export.JmeExporter;
38import com.jme3.export.JmeImporter;
39import com.jme3.export.OutputCapsule;
40import com.jme3.math.FastMath;
41import com.jme3.math.Vector3f;
42import com.jme3.scene.Mesh;
43import com.jme3.scene.VertexBuffer.Type;
44import static com.jme3.util.BufferUtils.*;
45import java.io.IOException;
46import java.nio.FloatBuffer;
47import java.nio.ShortBuffer;
48
49/**
50 * A parameterized torus, also known as a <em>pq</em> torus.
51 *
52 * @author Joshua Slack, Eric Woroshow
53 * @version $Revision: 4131 $, $Date: 2009-03-19 16:15:28 -0400 (Thu, 19 Mar 2009) $
54 */
55public class PQTorus extends Mesh {
56
57    private float p, q;
58
59    private float radius, width;
60
61    private int steps, radialSamples;
62
63    public PQTorus() {
64    }
65
66    /**
67     * Creates a parameterized torus.
68     * <p>
69     * Steps and radialSamples are both degree of accuracy values.
70     *
71     * @param p the x/z oscillation.
72     * @param q the y oscillation.
73     * @param radius the radius of the PQTorus.
74     * @param width the width of the torus.
75     * @param steps the steps along the torus.
76     * @param radialSamples radial samples for the torus.
77     */
78    public PQTorus(float p, float q, float radius, float width,
79            int steps, int radialSamples) {
80        super();
81        updateGeometry(p, q, radius, width, steps, radialSamples);
82    }
83
84    public float getP() {
85        return p;
86    }
87
88    public float getQ() {
89        return q;
90    }
91
92    public int getRadialSamples() {
93        return radialSamples;
94    }
95
96    public float getRadius() {
97        return radius;
98    }
99
100    public int getSteps() {
101        return steps;
102    }
103
104    public float getWidth() {
105        return width;
106    }
107
108    public void read(JmeImporter e) throws IOException {
109        super.read(e);
110        InputCapsule capsule = e.getCapsule(this);
111        p = capsule.readFloat("p", 0);
112        q = capsule.readFloat("q", 0);
113        radius = capsule.readFloat("radius", 0);
114        width = capsule.readFloat("width", 0);
115        steps = capsule.readInt("steps", 0);
116        radialSamples = capsule.readInt("radialSamples", 0);
117    }
118
119    /**
120     * Rebuilds this torus based on a new set of parameters.
121     *
122     * @param p the x/z oscillation.
123     * @param q the y oscillation.
124     * @param radius the radius of the PQTorus.
125     * @param width the width of the torus.
126     * @param steps the steps along the torus.
127     * @param radialSamples radial samples for the torus.
128     */
129    public void updateGeometry(float p, float q, float radius, float width, int steps, int radialSamples) {
130        this.p = p;
131        this.q = q;
132        this.radius = radius;
133        this.width = width;
134        this.steps = steps;
135        this.radialSamples = radialSamples;
136
137        final float thetaStep = (FastMath.TWO_PI / steps);
138        final float betaStep = (FastMath.TWO_PI / radialSamples);
139        Vector3f[] torusPoints = new Vector3f[steps];
140
141        // Allocate all of the required buffers
142        int vertCount = radialSamples * steps;
143
144        FloatBuffer fpb = createVector3Buffer(vertCount);
145        FloatBuffer fnb = createVector3Buffer(vertCount);
146        FloatBuffer ftb = createVector2Buffer(vertCount);
147
148        Vector3f pointB = new Vector3f(), T = new Vector3f(), N = new Vector3f(), B = new Vector3f();
149        Vector3f tempNorm = new Vector3f();
150        float r, x, y, z, theta = 0.0f, beta = 0.0f;
151        int nvertex = 0;
152
153        // Move along the length of the pq torus
154        for (int i = 0; i < steps; i++) {
155            theta += thetaStep;
156            float circleFraction = ((float) i) / (float) steps;
157
158            // Find the point on the torus
159            r = (0.5f * (2.0f + FastMath.sin(q * theta)) * radius);
160            x = (r * FastMath.cos(p * theta) * radius);
161            y = (r * FastMath.sin(p * theta) * radius);
162            z = (r * FastMath.cos(q * theta) * radius);
163            torusPoints[i] = new Vector3f(x, y, z);
164
165            // Now find a point slightly farther along the torus
166            r = (0.5f * (2.0f + FastMath.sin(q * (theta + 0.01f))) * radius);
167            x = (r * FastMath.cos(p * (theta + 0.01f)) * radius);
168            y = (r * FastMath.sin(p * (theta + 0.01f)) * radius);
169            z = (r * FastMath.cos(q * (theta + 0.01f)) * radius);
170            pointB = new Vector3f(x, y, z);
171
172            // Approximate the Frenet Frame
173            T = pointB.subtract(torusPoints[i]);
174            N = torusPoints[i].add(pointB);
175            B = T.cross(N);
176            N = B.cross(T);
177
178            // Normalise the two vectors and then use them to create an oriented circle
179            N = N.normalize();
180            B = B.normalize();
181            beta = 0.0f;
182            for (int j = 0; j < radialSamples; j++, nvertex++) {
183                beta += betaStep;
184                float cx = FastMath.cos(beta) * width;
185                float cy = FastMath.sin(beta) * width;
186                float radialFraction = ((float) j) / radialSamples;
187                tempNorm.x = (cx * N.x + cy * B.x);
188                tempNorm.y = (cx * N.y + cy * B.y);
189                tempNorm.z = (cx * N.z + cy * B.z);
190                fnb.put(tempNorm.x).put(tempNorm.y).put(tempNorm.z);
191                tempNorm.addLocal(torusPoints[i]);
192                fpb.put(tempNorm.x).put(tempNorm.y).put(tempNorm.z);
193                ftb.put(radialFraction).put(circleFraction);
194            }
195        }
196
197        // Update the indices data
198        ShortBuffer sib = createShortBuffer(6 * vertCount);
199        for (int i = 0; i < vertCount; i++) {
200            sib.put(new short[] {
201                    (short)(i),
202                    (short)(i - radialSamples),
203                    (short)(i + 1),
204                    (short)(i + 1),
205                    (short)(i - radialSamples),
206                    (short)(i - radialSamples + 1)
207            });
208        }
209        for (int i = 0, len = sib.capacity(); i < len; i++) {
210            int ind = sib.get(i);
211            if (ind < 0) {
212                ind += vertCount;
213                sib.put(i, (short) ind);
214            } else if (ind >= vertCount) {
215                ind -= vertCount;
216                sib.put(i, (short) ind);
217            }
218        }
219        sib.rewind();
220
221        setBuffer(Type.Position, 3, fpb);
222        setBuffer(Type.Normal,   3, fnb);
223        setBuffer(Type.TexCoord, 2, ftb);
224        setBuffer(Type.Index,    3, sib);
225    }
226
227    @Override
228    public void write(JmeExporter e) throws IOException {
229        super.write(e);
230        OutputCapsule capsule = e.getCapsule(this);
231        capsule.write(p, "p", 0);
232        capsule.write(q, "q", 0);
233        capsule.write(radius, "radius", 0);
234        capsule.write(width, "width", 0);
235        capsule.write(steps, "steps", 0);
236        capsule.write(radialSamples, "radialSamples", 0);
237    }
238
239}