Here's a chainlink class!

1 files changed, 214 insertions, 0 deletions

diff --git a/src/tesseract/objects/ChainLink2.java b/src/tesseract/objects/ChainLink2.java
new file mode 100644
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+++ b/src/tesseract/objects/ChainLink2.java
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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;
+		
+		// Translate the coords to the correct place.
+		Transform3D t3d = new Transform3D();
+		
+		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)));
+			
+			// Move to the right place.
+			//t3d.transform(coords[0][i]);
+		}
+		
+		// Create the arc
+		radius = (width - radius) / 2.0f;
+		
+		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();
+		//new Vector3f(-(length / 2.0f - radius), -width / 2.0f, 0));
+		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);
+		
+		// TODO: Remove /2
+		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;		
+	}
+
+}