/*******************************************************************************
 * Copyright (c) 2012, 2013 Association for Decentralized Information Management in
 * Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.g3d.shape;

import java.util.ArrayList;
import java.util.List;

import javax.vecmath.AxisAngle4d;
import javax.vecmath.Vector3d;

import org.simantics.g3d.math.MathTools;

public class Sphere {

	public static Mesh create(double radius, int s, int p) {
		if (s < 3 || p < 3 || radius < MathTools.NEAR_ZERO)
			throw new IllegalArgumentException();
		List<Vector3d> vertices = new ArrayList<Vector3d>((s-2)*p + 2);
		List<Vector3d> normals = new ArrayList<Vector3d>(vertices.size());
		List<Integer> indices = new ArrayList<Integer>(((s-3)*p*2 + p * 2)*3);
		Vector3d v = new Vector3d(0.0,-radius,0.0);
		Vector3d vp = new Vector3d();
		for (int ip = 0; ip < p; ip++) {
			if (ip == 0) {
				vertices.add(new Vector3d(0.0,-radius,0.0));
			} else if (ip == p - 1) {
				vertices.add(new Vector3d(0.0, radius,0.0));
				int off = 1 + (ip-2)*s;
				for (int is = 0; is < s; is++) {
					indices.add(vertices.size() - 1);
					indices.add(is+off);
					if (is < s -1)
						indices.add(is+off+1);
					else
						indices.add(off);
					
					
				}
			} else {
				AxisAngle4d aa = new AxisAngle4d(1, 0, 0, ((double)ip/(double)(p-1))*Math.PI);
				MathTools.rotate(MathTools.getQuat(aa), v, vp);
				for (int is = 0; is < s; is++) {
					aa = new AxisAngle4d(0, 1, 0, ((double)is/(double)s)*Math.PI*2);
					Vector3d vs = new Vector3d();
					MathTools.rotate(MathTools.getQuat(aa), vp, vs);
					vertices.add(vs);
				}
				if (ip == 1) {
					for (int is = 0; is < s; is++) {
						indices.add(0);
						if (is < s -1)
							indices.add(is+2);
						else
							indices.add(1);
						indices.add(is+1);
					}
				} else {
					int off = 1 + (ip-1)*s;
					for (int is = 0; is < s-1; is++) {
						indices.add(off + is - s);
						indices.add(off + is+1);
						indices.add(off + is);
						
						
						indices.add(off + is - s);
						indices.add(off + is + 1 - s);
						indices.add(off + is + 1);
						
					}
					indices.add(off - 1);
					indices.add(off);
					indices.add(off + s - 1);
					
					indices.add(off -1);
					indices.add(off - s);
					indices.add(off);
					
				}
			}
		}
		for (int i = 0; i < vertices.size(); i++) {
			Vector3d n = new Vector3d(vertices.get(i));
			n.normalize();
			normals.add(n);
		}
		
		return Mesh.create(vertices,normals,indices);
		
	}
	
	public static void main(String arg[]) {
		Mesh s1 = create(1.0, 3, 3);
		Mesh s2 = create(1.0, 4, 4);
		System.out.println("debug " + s1 + " " + s2);
	}
}