t3dgeometry.java~31~

来自「是用jbuilder实现的一些原代码程序」· JAVA~31~ 代码 · 共 79 行

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 static final float sqrt3_3 = sqrt3 / 3.0f;
    private static final float sqrt24_3 = (float) Math.sqrt(24.0) / 3.0f;

    private static final float ycenter = 0.5f * sqrt24_3;
    private static final float zcenter = -sqrt3_3;

    private static final Point3f p1 = new Point3f(-1.0f, -ycenter, -zcenter);
    private static final Point3f p2 = new Point3f(1.0f, -ycenter, -zcenter);
    private static final Point3f p3 =
        new Point3f(0.0f, -ycenter, -sqrt3 - zcenter);
    private static final Point3f p4 =
        new Point3f(0.0f, sqrt24_3 - ycenter, 0.0f);

    private static final Point3f[] verts = {
        p1, p2, p4,	// front face
        p1, p4, p3,	// left, back face
        p2, p3, p4,	// right, back face
        p1, p3, p2,	// bottom face
    };

    private TexCoord2f texCoord[] = {
        new TexCoord2f(0.0f, 0.0f),
        new TexCoord2f(1.0f, 0.0f),
        new TexCoord2f(0.5f, sqrt3 / 2.0f),
    };

    public T3DGeometry() {
        int i;

        TriangleArray tetra = new TriangleArray(12, TriangleArray.COORDINATES |
                TriangleArray.NORMALS | TriangleArray.TEXTURE_COORDINATE_2);

        tetra.setCoordinates(0, verts);
        for (i = 0; i < 12; 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 < 4; 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(new Appearance());
    }
}