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/*
 * Copyright (c) 2007 Sun Microsystems, Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistribution of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in
 *   the documentation and/or other materials provided with the
 *   distribution.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
 * EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL
 * NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF
 * USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR
 * ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
 * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
 * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
 * INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 *
 * You acknowledge that this software is not designed, licensed or
 * intended for use in the design, construction, operation or
 * maintenance of any nuclear facility.
 *
 */

package com.sun.j3d.utils.geometry;

import javax.media.j3d.Appearance;
import javax.media.j3d.Node;
import javax.media.j3d.NodeComponent;
import javax.media.j3d.Shape3D;
import javax.vecmath.Point3f;
import javax.vecmath.TexCoord2f;
import javax.vecmath.Vector3f;

/**
 * Sphere is a geometry primitive created with a given radius and resolution.
 * It is centered at the origin.
 * 
 * When a texture is applied to a Sphere, it is mapped CCW from the back
 * of the sphere.
 * 

 * By default all primitives with the same parameters share their
 * geometry (e.g., you can have 50 shperes in your scene, but the
 * geometry is stored only once). A change to one primitive will
 * effect all shared nodes.  Another implication of this
 * implementation is that the capabilities of the geometry are shared,
 * and once one of the shared nodes is live, the capabilities cannot
 * be set.  Use the GEOMETRY_NOT_SHARED flag if you do not wish to
 * share geometry among primitives with the same parameters.
 */

public class Sphere extends Primitive {

  /**
   * Sphere shape identifier, used by getShape.
   *
   * @see Sphere#getShape
   */
  public static final int BODY = 0;

  static final int MID_REZ_DIV = 16;
  float  radius;
  int    divisions;

  /**
   *   Constructs a Sphere of a given radius. Normals are generated
   *   by default, texture coordinates are not. The resolution defaults to
   *   15 divisions along sphere's axes. Appearance defaults to white.
   *   @param radius Radius
   */
  public Sphere (float radius) {
    this(radius,  GENERATE_NORMALS, MID_REZ_DIV);
  }

  /**
   *   Constructs a default Sphere of radius of 1.0. Normals are generated
   *   by default, texture coordinates are not.
   *   Resolution defaults to 15 divisions. Appearance defaults to white.
   */
  public Sphere() {
    this(1.0f, GENERATE_NORMALS, MID_REZ_DIV);
  }

  /**
   *   Constructs a Sphere of a given radius and appearance.
   *   Normals are generated by default, texture coordinates are not.
   *   @param radius Radius
   *   @param ap Appearance
   */

  public Sphere (float radius, Appearance ap) {
    this(radius, GENERATE_NORMALS, MID_REZ_DIV, ap);
  }

  /**
   *   Constructs a Sphere of a given radius and appearance with
   *   additional parameters specified by the Primitive flags.
   *   @param radius Radius
   *   @param primflags
   *   @param ap appearance
   */
  public Sphere(float radius, int primflags, Appearance ap) {
    this(radius, primflags, MID_REZ_DIV, ap);
  }

  /**
   *   Constructs a Sphere of a given radius and number of divisions
   *   with additional parameters specified by the Primitive flags.
   *   Appearance defaults to white.
   *   @param radius Radius
   *   @param divisions Divisions
   *   @param primflags Primflags
   */
  public Sphere(float radius, int primflags, int divisions) {
    this(radius, primflags, divisions, null);
  }


  /**
   * Obtains Sphere's shape node that contains the geometry.
   * This allows users to modify the appearance or geometry.
   * @param partId The part to return (must be BODY for Spheres)
   * @return The Shape3D object associated with the partId.  If an
   * invalid partId is passed in, null is returned.
   */
  @Override
  public Shape3D getShape(int partId) {
    if (partId != BODY) return null;
//     return (Shape3D)((Group)getChild(0)).getChild(BODY);
    return (Shape3D)getChild(BODY);
  }

  /** Obtains Sphere's shape node that contains the geometry.
   */
  public Shape3D getShape() {
//     return (Shape3D)((Group)getChild(0)).getChild(BODY);
      return (Shape3D)getChild(BODY);
  }

  /** Sets appearance of the Sphere.
   */
  @Override
  public void setAppearance(Appearance ap) {
//     ((Shape3D)((Group)getChild(0)).getChild(BODY)).setAppearance(ap);
      ((Shape3D)getChild(BODY)).setAppearance(ap);
  }

    /**
     * Gets the appearance of the specified part of the sphere.
     *
     * @param partId identifier for a given subpart of the sphere
     *
     * @return The appearance object associated with the partID.  If an
     * invalid partId is passed in, null is returned.
     *
     * @since Java 3D 1.2.1
     */
    @Override
    public Appearance getAppearance(int partId) {
	if (partId != BODY) return null;
	return getShape(partId).getAppearance();
    }


  /**
   *   Constructs a customized Sphere of a given radius,
   *   number of divisions, and appearance, with additional parameters
   *   specified by the Primitive flags.  The resolution is defined in
   *   terms of number of subdivisions along the sphere's axes. More
   *   divisions lead to more finely tesselated objects.
   *   
   *   If the appearance is null, the sphere defaults to a white appearance.
   */
  public Sphere(float radius, int primflags, int divisions, Appearance ap) {
    super();

    int sign;
    int n, nstep;

    this.radius = radius;
    this.divisions = divisions;

    /*
     *     The sphere algorithm evaluates spherical angles along regular
     * units. For each spherical coordinate, (theta, rho), a (x,y,z) is
     * evaluated (along with the normals and texture coordinates).
     *
     *       The spherical angles theta varies from 0 to 2pi and rho from 0
     * to pi. Sample points depends on the number of divisions.
     */

    flags = primflags;
    boolean texCoordYUp = (flags & GENERATE_TEXTURE_COORDS_Y_UP) != 0;

    //Depending on whether normal inward bit is set.
    if ((flags & GENERATE_NORMALS_INWARD) != 0) {
	sign = -1;
    } else {
	sign = 1;
    }

    if (divisions < 4) {
	nstep = 1;
	n = 4;
    } else {
	int mod = divisions % 4;
	if (mod == 0) {
	    n = divisions;
	} else {
	    n = divisions + (4 - mod);
	}
	nstep = n/4;
    }


    GeomBuffer cache = getCachedGeometry(Primitive.SPHERE,
					 radius, 0.0f, 0.0f,
					 divisions, 0, primflags);

    Shape3D shape;

    if (cache != null) {
	shape = new Shape3D(cache.getComputedGeometry());
	numVerts += cache.getNumVerts();
	numTris += cache.getNumTris();
    } else {
	// buffer size = 8*(1 + 2E{i} + (nstep+1))
	//         where E{i} = sum of i = 2 ... nstep
	GeomBuffer gbuf = new GeomBuffer(8*nstep*(nstep+2));

	for (int i=0; i < 4; i++) {
	    buildQuadrant(gbuf, i*Math.PI/2, (i+1)*Math.PI/2, sign, nstep, n, true);
	    buildQuadrant(gbuf, i*Math.PI/2, (i+1)*Math.PI/2, sign, nstep, n, false);
	}

        // Fix to Issue 411. Java 3D prefers images used for texture mapping to be Y-up
        if (texCoordYUp) {
            TexCoord2f[] texCoords  = gbuf.getTexCoords();
            if (texCoords != null) {
                for (int ii=0; iicloneTree to duplicate the current node.
     * cloneNode should be overridden by any user subclassed
     * objects.  All subclasses must have their cloneNode
     * method consist of the following lines:
     * 
     *     public Node cloneNode(boolean forceDuplicate) {
     *         UserSubClass usc = new UserSubClass();
     *         usc.duplicateNode(this, forceDuplicate);
     *         return usc;
     *     }
     * 
     * @param forceDuplicate when set to true, causes the
     *  duplicateOnCloneTree flag to be ignored.  When
     *  false, the value of each node's
     *  duplicateOnCloneTree variable determines whether
     *  NodeComponent data is duplicated or copied.
     *
     * @see Node#cloneTree
     * @see Node#duplicateNode
     * @see NodeComponent#setDuplicateOnCloneTree
     */
    @Override
    public Node cloneNode(boolean forceDuplicate) {
        Sphere s = new Sphere(radius, flags, divisions, getAppearance());
        s.duplicateNode(this, forceDuplicate);

        return s;
    }

    /**
     * Copies all node information from originalNode into
     * the current node.  This method is called from the
     * cloneNode method which is, in turn, called by the
     * cloneTree method.
     * 
     * For any NodeComponent objects
     * contained by the object being duplicated, each NodeComponent
     * object's duplicateOnCloneTree value is used to determine
     * whether the NodeComponent should be duplicated in the new node
     * or if just a reference to the current node should be placed in the
     * new node.  This flag can be overridden by setting the
     * forceDuplicate parameter in the cloneTree
     * method to true.
     *
     * @param originalNode the original node to duplicate.
     * @param forceDuplicate when set to true, causes the
     *  duplicateOnCloneTree flag to be ignored.  When
     *  false, the value of each node's
     *  duplicateOnCloneTree variable determines whether
     *  NodeComponent data is duplicated or copied.
     *
     * @see Node#cloneTree
     * @see Node#cloneNode
     * @see NodeComponent#setDuplicateOnCloneTree
     */
    @Override
    public void duplicateNode(Node originalNode, boolean forceDuplicate) {
        super.duplicateNode(originalNode, forceDuplicate);
    }

    /**
     * Returns the radius of the sphere
     *
     * @since Java 3D 1.2.1
     */
    public float getRadius() {
	return radius;
    }

    /**
     * Returns the number of divisions
     *
     * @since Java 3D 1.2.1
     */
    public int getDivisions() {
	return divisions;
    }

    void buildQuadrant(GeomBuffer gbuf, double startDelta, double endDelta,
		       int sign, int nstep, int n, boolean upperSphere)
    {

	double ds, dt, theta, delta;
	int i, j, index, i2;
	double h, r, vx, vz;
	Point3f pt;
	Vector3f norm;
	TexCoord2f texCoord;
	double starth;
	double t;
	boolean leftToRight;


	if (upperSphere) {
            dt = Math.PI/(2*nstep);
            theta = dt;
            starth = 1;
	    leftToRight = (sign > 0);
        } else {
            dt = -Math.PI/(2*nstep);
            theta = Math.PI + dt;
            starth = -1;
	    leftToRight = (sign < 0);
        }


	for (i = 1; i <= nstep; i++) {
	    h = Math.cos(theta);
	    r = Math.sin(theta);
	    if (sign > 0) {
		t = 1 - theta/Math.PI;
	    } else {
		t = theta/Math.PI;
	    }

	    i2 = i << 1;
	    // subdivision decreases towards the pole
	    ds =  (endDelta - startDelta) / i;

	    gbuf.begin(GeomBuffer.TRIANGLE_STRIP);

	    if (leftToRight) {
		// Build triangle strips from left to right
		delta =  startDelta;

		for (j=0; j < i; j++) {
		    vx = r*Math.cos(delta);
		    vz = r*Math.sin(delta);

		    gbuf.normal3d( vx*sign, h*sign, vz*sign );
		    gbuf.texCoord2d(0.75 - delta/(2*Math.PI), t);
		    gbuf.vertex3d( vx*radius, h*radius, vz*radius );
		    if (i > 1) {
			// get previous vertex from buffer
			index = gbuf.currVertCnt - i2;
			pt = gbuf.pts[index];
			norm = gbuf.normals[index];
			texCoord = gbuf.tcoords[index];
			// connect with correspondent vertices from previous row
			gbuf.normal3d(norm.x, norm.y, norm.z);
			gbuf.texCoord2d(texCoord.x, texCoord.y);
			gbuf.vertex3d(pt.x, pt.y, pt.z);
		    } else {
			gbuf.normal3d(0, sign*starth, 0);
			if (sign > 0) {
			    gbuf.texCoord2d(0.75 - (startDelta + endDelta)/(4*Math.PI),
					    1.0 - (theta - dt)/Math.PI);
			} else {
			    gbuf.texCoord2d(0.75 - (startDelta + endDelta)/(4*Math.PI),
					    (theta - dt)/Math.PI);
			}
                        gbuf.vertex3d( 0, starth*radius, 0);

		    }
		    delta += ds;
		}

		// Put the last vertex in that row,
		// for numerical accuracy we don't use delta
		// compute from above.
		delta = endDelta;
		vx = r*Math.cos(delta);
		vz = r*Math.sin(delta);
		gbuf.normal3d( vx*sign, h*sign, vz*sign );
		gbuf.texCoord2d(0.75 - delta/(2*Math.PI), t);
		gbuf.vertex3d( vx*radius, h*radius, vz*radius);
	    } else {
		delta =  endDelta;
		// Build triangle strips from right to left
		for (j=i; j > 0; j--) {
		    vx = r*Math.cos(delta);
		    vz = r*Math.sin(delta);

		    gbuf.normal3d( vx*sign, h*sign, vz*sign );
		    // Convert texture coordinate back to one
		    // set in previous version
		    gbuf.texCoord2d(0.75 - delta/(2*Math.PI), t);
		    gbuf.vertex3d( vx*radius, h*radius, vz*radius );
		    if (i > 1) {
			// get previous vertex from buffer
			index = gbuf.currVertCnt - i2;
			pt = gbuf.pts[index];
			norm = gbuf.normals[index];
			texCoord = gbuf.tcoords[index];
			gbuf.normal3d(norm.x, norm.y, norm.z);
			gbuf.texCoord2d(texCoord.x, texCoord.y);
			gbuf.vertex3d(pt.x, pt.y, pt.z);
		    } else {
			gbuf.normal3d(0, sign*starth, 0);
			if (sign > 0) {
			    gbuf.texCoord2d(0.75 - (startDelta + endDelta)/(4*Math.PI),
					    1.0 - (theta - dt)/Math.PI);
			} else {
			    gbuf.texCoord2d(0.75 - (startDelta + endDelta)/(4*Math.PI),
					    (theta - dt)/Math.PI);
			}
                        gbuf.vertex3d( 0, starth*radius, 0);

		    }
		    delta -= ds;
		}

		// Put the last vertex in that row,
		// for numerical accuracy we don't use delta
		// compute from above.
		delta = startDelta;
		vx = r*Math.cos(delta);
		vz = r*Math.sin(delta);
		gbuf.normal3d( vx*sign, h*sign, vz*sign );
		gbuf.texCoord2d(0.75 - delta/(2*Math.PI), t);
		gbuf.vertex3d( vx*radius, h*radius, vz*radius );

	    }

	    gbuf.end();

	    if (i < nstep) {
		theta += dt;
	    } else { // take care of numerical imprecision
		theta = Math.PI/2;
	    }
	}

    }
}