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package tesseract.objects;
import javax.media.j3d.Appearance;
import javax.media.j3d.IndexedQuadArray;
import javax.media.j3d.Material;
import javax.media.j3d.PointArray;
import javax.media.j3d.Shape3D;
import javax.media.j3d.Transform3D;
import javax.vecmath.Point3f;
import javax.vecmath.Vector3f;
import com.sun.j3d.utils.geometry.GeometryInfo;
import com.sun.j3d.utils.geometry.NormalGenerator;
/**
* Chain link object.
*
* @author Jesse Morgan
*/
public class ChainLink2 extends PhysicalObject {
/**
* Default link length.
*/
public static final float DEFAULT_LENGTH = 0.15f;
/**
* Default ratio of length to width.
*/
public static final float DEFAULT_WIDTH_RATIO = 0.75f;
/**
* Default ratio of length to link diameter.
*/
public static final float DEFAULT_DIAMETER_RATIO = 0.25f;
/**
* Number of slices to render.
*/
protected static final int SLICE_COUNT = 40;
/**
* Number of points in the circumference of the circle.
*/
protected static final int SLICE_DIVISIONS = 16;
/**
* Construct a chain link.
*
* @param thePosition Position.
* @param mass Mass.
*/
public ChainLink2(final Vector3f thePosition, final float mass) {
this(thePosition, mass, DEFAULT_LENGTH * DEFAULT_DIAMETER_RATIO,
DEFAULT_LENGTH, DEFAULT_LENGTH * DEFAULT_WIDTH_RATIO);
}
/**
* Construct a chain link.
*
* @param thePosition Position.
* @param mass Mass.
* @param length Link length.
* Width and diameter are created from the default ratios.
*/
public ChainLink2(final Vector3f thePosition, final float mass,
final float length) {
this(thePosition, mass, length * DEFAULT_DIAMETER_RATIO,
length, length * DEFAULT_WIDTH_RATIO);
}
/**
* Construct a Chain Link.
*
* @param thePosition Position.
* @param mass Mass.
* @param diameter Diameter of link.
* @param length Length of link.
* @param width Width of link.
*/
public ChainLink2(final Vector3f thePosition, final float mass,
final float diameter, final float length, final float width) {
super(thePosition, mass);
setShape(createShape(SLICE_COUNT, SLICE_DIVISIONS,
diameter, length, width));
}
/**
* Create the shape.
*
* @param sliceCount Number of slices.
* @param sliceDivisions Number of divisions.
* @param diameter Diameter.
* @param length Length.
* @param width Width.
*
* @return Chainlink shape.
*/
public Shape3D createShape(final int sliceCount, final int sliceDivisions,
final float diameter, final float length, final float width) {
Point3f[][] coords = new Point3f[sliceCount][sliceDivisions];
// Design the first circle
double theta = 2 * Math.PI / sliceDivisions;
float radius = diameter / 2.0f;
for (int i = 0; i < sliceDivisions; i++) {
coords[0][i] = new Point3f(
0f,
(float) (radius * Math.cos(i * theta)),
(float) (radius * Math.sin(i * theta)));
}
// Create the arc
radius = (width - radius) / 2.0f;
Transform3D t3d = new Transform3D();
t3d.setIdentity();
t3d.setTranslation(new Vector3f(0, -radius, 0));
Transform3D tmp = new Transform3D();
tmp.rotZ(Math.PI / (sliceCount / 2.0 - 1));
t3d.mul(tmp);
tmp.setIdentity();
tmp.setTranslation(new Vector3f(0, radius, 0));
t3d.mul(tmp);
for (int j = 1; j < sliceCount / 2; j++) {
for (int i = 0; i < sliceDivisions; i++) {
coords[j][i] = new Point3f(coords[j - 1][i]);
t3d.transform(coords[j][i]);
}
}
// Next build second half...
t3d.setIdentity();
t3d.setTranslation(new Vector3f(
-(length / 2.0f - radius / 2.0f),
(width - diameter / 2.0f) / 2.0f,
0));
Transform3D rot = new Transform3D();
rot.rotY(Math.PI);
tmp.setIdentity();
tmp.rotX(Math.PI);
rot.mul(tmp);
for (int j = 0; j < sliceCount / 2; j++) {
for (int i = 0; i < sliceDivisions; i++) {
t3d.transform(coords[j][i]);
coords[j + sliceCount / 2][i] = new Point3f(coords[j][i]);
rot.transform(coords[j + sliceCount / 2][i]);
}
}
// Build Geoemetry
IndexedQuadArray geometry = new IndexedQuadArray(
sliceCount * sliceDivisions,
PointArray.COORDINATES,
4 * sliceDivisions * sliceCount);
for (int i = 0; i < sliceCount; i++) {
geometry.setCoordinates(i * sliceDivisions, coords[i]);
}
int index = 0;
for (int j = 0; j < (sliceCount - 1); j++) {
for (int i = 0; i < sliceDivisions; i++) {
geometry.setCoordinateIndex(index++, j * sliceDivisions + i);
geometry.setCoordinateIndex(index++,
(j + 1) * sliceDivisions + i);
geometry.setCoordinateIndex(index++,
(j + 1) * sliceDivisions + (i + 1) % sliceDivisions);
geometry.setCoordinateIndex(index++,
j * sliceDivisions + (i + 1) % sliceDivisions);
}
}
for (int i = 0; i < sliceDivisions; i++) {
geometry.setCoordinateIndex(index++,
(sliceCount - 1) * sliceDivisions + i);
geometry.setCoordinateIndex(index++,
i);
geometry.setCoordinateIndex(index++,
(i + 1) % sliceDivisions);
geometry.setCoordinateIndex(index++,
(sliceCount - 1) * sliceDivisions
+ (i + 1) % sliceDivisions);
}
GeometryInfo gInfo = new GeometryInfo(geometry);
gInfo.convertToIndexedTriangles();
new NormalGenerator().generateNormals(gInfo);
Shape3D shape = new Shape3D(gInfo.getGeometryArray());
Appearance app = new Appearance();
Material mat = new Material();
mat.setDiffuseColor(1, 0, 0);
app.setMaterial(mat);
shape.setAppearance(app);
return shape;
}
}
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