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* Copyright (c) 2009-2012 jMonkeyEngine
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// $Id: PQTorus.java 4131 2009-03-19 20:15:28Z blaine.dev $
package com.jme3.scene.shape;
import com.jme3.export.InputCapsule;
import com.jme3.export.JmeExporter;
import com.jme3.export.JmeImporter;
import com.jme3.export.OutputCapsule;
import com.jme3.math.FastMath;
import com.jme3.math.Vector3f;
import com.jme3.scene.Mesh;
import com.jme3.scene.VertexBuffer.Type;
import static com.jme3.util.BufferUtils.*;
import java.io.IOException;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;
/**
* A parameterized torus, also known as a <em>pq</em> torus.
*
* @author Joshua Slack, Eric Woroshow
* @version $Revision: 4131 $, $Date: 2009-03-19 16:15:28 -0400 (Thu, 19 Mar 2009) $
*/
public class PQTorus extends Mesh {
private float p, q;
private float radius, width;
private int steps, radialSamples;
public PQTorus() {
}
/**
* Creates a parameterized torus.
* <p>
* Steps and radialSamples are both degree of accuracy values.
*
* @param p the x/z oscillation.
* @param q the y oscillation.
* @param radius the radius of the PQTorus.
* @param width the width of the torus.
* @param steps the steps along the torus.
* @param radialSamples radial samples for the torus.
*/
public PQTorus(float p, float q, float radius, float width,
int steps, int radialSamples) {
super();
updateGeometry(p, q, radius, width, steps, radialSamples);
}
public float getP() {
return p;
}
public float getQ() {
return q;
}
public int getRadialSamples() {
return radialSamples;
}
public float getRadius() {
return radius;
}
public int getSteps() {
return steps;
}
public float getWidth() {
return width;
}
/**
* Rebuilds this torus based on a new set of parameters.
*
* @param p the x/z oscillation.
* @param q the y oscillation.
* @param radius the radius of the PQTorus.
* @param width the width of the torus.
* @param steps the steps along the torus.
* @param radialSamples radial samples for the torus.
*/
public void updateGeometry(float p, float q, float radius, float width, int steps, int radialSamples) {
this.p = p;
this.q = q;
this.radius = radius;
this.width = width;
this.steps = steps;
this.radialSamples = radialSamples;
final float thetaStep = (FastMath.TWO_PI / steps);
final float betaStep = (FastMath.TWO_PI / radialSamples);
Vector3f[] torusPoints = new Vector3f[steps];
// Allocate all of the required buffers
int vertCount = radialSamples * steps;
FloatBuffer fpb = createVector3Buffer(vertCount);
FloatBuffer fnb = createVector3Buffer(vertCount);
FloatBuffer ftb = createVector2Buffer(vertCount);
Vector3f pointB, T, N, B;
Vector3f tempNorm = new Vector3f();
float r, x, y, z, theta = 0.0f, beta;
int nvertex = 0;
// Move along the length of the pq torus
for (int i = 0; i < steps; i++) {
theta += thetaStep;
float circleFraction = ((float) i) / (float) steps;
// Find the point on the torus
r = (0.5f * (2.0f + FastMath.sin(q * theta)) * radius);
x = (r * FastMath.cos(p * theta) * radius);
y = (r * FastMath.sin(p * theta) * radius);
z = (r * FastMath.cos(q * theta) * radius);
torusPoints[i] = new Vector3f(x, y, z);
// Now find a point slightly farther along the torus
r = (0.5f * (2.0f + FastMath.sin(q * (theta + 0.01f))) * radius);
x = (r * FastMath.cos(p * (theta + 0.01f)) * radius);
y = (r * FastMath.sin(p * (theta + 0.01f)) * radius);
z = (r * FastMath.cos(q * (theta + 0.01f)) * radius);
pointB = new Vector3f(x, y, z);
// Approximate the Frenet Frame
T = pointB.subtract(torusPoints[i]);
N = torusPoints[i].add(pointB);
B = T.cross(N);
N = B.cross(T);
// Normalise the two vectors and then use them to create an oriented circle
N = N.normalize();
B = B.normalize();
beta = 0.0f;
for (int j = 0; j < radialSamples; j++, nvertex++) {
beta += betaStep;
float cx = FastMath.cos(beta) * width;
float cy = FastMath.sin(beta) * width;
float radialFraction = ((float) j) / radialSamples;
tempNorm.x = (cx * N.x + cy * B.x);
tempNorm.y = (cx * N.y + cy * B.y);
tempNorm.z = (cx * N.z + cy * B.z);
fnb.put(tempNorm.x).put(tempNorm.y).put(tempNorm.z);
tempNorm.addLocal(torusPoints[i]);
fpb.put(tempNorm.x).put(tempNorm.y).put(tempNorm.z);
ftb.put(radialFraction).put(circleFraction);
}
}
// Update the indices data
ShortBuffer sib = createShortBuffer(6 * vertCount);
for (int i = 0; i < vertCount; i++) {
sib.put(new short[] {
(short)(i),
(short)(i - radialSamples),
(short)(i + 1),
(short)(i + 1),
(short)(i - radialSamples),
(short)(i - radialSamples + 1)
});
}
for (int i = 0, len = sib.capacity(); i < len; i++) {
int ind = sib.get(i);
if (ind < 0) {
ind += vertCount;
sib.put(i, (short) ind);
} else if (ind >= vertCount) {
ind -= vertCount;
sib.put(i, (short) ind);
}
}
sib.rewind();
setBuffer(Type.Position, 3, fpb);
setBuffer(Type.Normal, 3, fnb);
setBuffer(Type.TexCoord, 2, ftb);
setBuffer(Type.Index, 3, sib);
}
@Override
public void read(JmeImporter e) throws IOException {
super.read(e);
InputCapsule capsule = e.getCapsule(this);
p = capsule.readFloat("p", 0);
q = capsule.readFloat("q", 0);
radius = capsule.readFloat("radius", 0);
width = capsule.readFloat("width", 0);
steps = capsule.readInt("steps", 0);
radialSamples = capsule.readInt("radialSamples", 0);
}
@Override
public void write(JmeExporter e) throws IOException {
super.write(e);
OutputCapsule capsule = e.getCapsule(this);
capsule.write(p, "p", 0);
capsule.write(q, "q", 0);
capsule.write(radius, "radius", 0);
capsule.write(width, "width", 0);
capsule.write(steps, "steps", 0);
capsule.write(radialSamples, "radialSamples", 0);
}
}