t3dgeometry.java~42~

利用Java 3D API来编写的一个Java三维动画的演示程序。这个程序将在中央显示一行3D的文字

package j3ddemo;

import javax.media.j3d.Shape3D;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.geometry.*;
import com.sun.j3d.utils.universe.*;
import javax.media.j3d.*;
import javax.vecmath.*;
import com.sun.j3d.utils.behaviors.vp.*;

/**
 * <p>Title: Java 3D Demo</p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: </p>
 * @author Sttony
 * @version 1.0
 */

public class T3DGeometry extends Shape3D {
  private static final float sqrt3 = (float) Math.sqrt(3.0);
  private TexCoord2f texCoord[] = {
      new TexCoord2f(0.5f, sqrt3 / 2.0f),
      new TexCoord2f(0.5f, sqrt3 / 2.0f),
      new TexCoord2f(0.5f, sqrt3 / 2.0f),
      new TexCoord2f(0.5f, sqrt3 / 2.0f),
      new TexCoord2f(0.5f, sqrt3 / 2.0f),
  };

  public T3DGeometry(float size, Appearance ap) {
    Point3f p1 = new Point3f(size, 0.0f, 0.0f);
    Point3f p2 = new Point3f(0.0f, size, 0.0f);
    Point3f p3 = new Point3f( -size, 0.0f, 0.0f);
    Point3f p4 = new Point3f(0.0f, 0.0f, size);
    Point3f p5 = new Point3f(0.0f,0.0f,-size);
    Point3f[] verts = {
        p1, p2, p4,
        p2, p3, p4,
        p1, p4, p3,
        p1, p5, p2,
        p2, p5, p3,
        p5, p2, p1,
        p1, p3, p5,
    };

    int i;

    TriangleArray tetra = new TriangleArray(15, TriangleArray.COORDINATES |
                                            TriangleArray.NORMALS |
                                            TriangleArray.TEXTURE_COORDINATE_2);

    tetra.setCoordinates(0, verts);
    for (i = 0; i < 15; i++) {
      tetra.setTextureCoordinate(0, i, texCoord[i % 3]);
    }

    int face;
    Vector3f normal = new Vector3f();
    Vector3f v1 = new Vector3f();
    Vector3f v2 = new Vector3f();
    Point3f[] pts = new Point3f[3];
    for (i = 0; i < 3; i++)
      pts[i] = new Point3f();

    for (face = 0; face < 5; face++) {
      tetra.getCoordinates(face * 3, pts);
      v1.sub(pts[1], pts[0]);
      v2.sub(pts[2], pts[0]);
      normal.cross(v1, v2);
      normal.normalize();
      for (i = 0; i < 3; i++) {
        tetra.setNormal( (face * 3 + i), normal);
      }
    }
    this.setGeometry(tetra);
    this.setAppearance(ap);
  }
}