pointshape.java

用java3d做的一个粒子系统可以控制粒子运动

import javax.media.j3d.*;
import javax.vecmath.*;

final class PointShape extends PointArray {

    private Point3d[] coord;
    private Color3f[] color;
    private int numPoints;
    private double invNumPoints;

    public PointShape(int numPoints){

        super(numPoints, COLOR_3 | COORDINATES);

	setCapability(ALLOW_COLOR_WRITE);
        setCapability(ALLOW_COORDINATE_WRITE);
        
        this.numPoints = numPoints;
	invNumPoints = 1.0/numPoints;

        coord = new Point3d[numPoints];
        color = new Color3f[numPoints];
	
        for(int i=0;i<numPoints;i++){
            coord[i] = new Point3d();
            color[i] = new Color3f();
        }
    }


    void update(double localTime){

        double localTime_2 = -0.5 * localTime;

	double s = 1;
	double t = localTime;
	double tinc = localTime*invNumPoints;

        for (int i=numPoints; --i>=0; ) {

	    //double s = invNumPoints * i;
	    s -= invNumPoints;
	    
	    //double t = localTime * s;
	    t -= tinc;
            
            int angle_idx  = (int) (0xffff & (long) (13627.0*(t+localTime_2)));
            int radius_idx = (int) (0xffff & (long) (15646.0*t));
            int height_idx = (int) (0xffff & (long) (9970.0*t));
            
            double radius = 1.0 + 0.75 * Particles.COS[radius_idx];
            
            //double x = Particles.COS[angle_idx] * radius;
            //double y = Particles.SIN[angle_idx] * radius;
            double z = Particles.SIN[height_idx];

	    //coord[i].set(x,y,z);

	    Point3d point = coord[i];
	    point.x=Particles.COS[angle_idx] * radius;
	    point.y=Particles.SIN[angle_idx] * radius;
	    point.z=Particles.SIN[height_idx];
            
            //color[i].set((float) s,
	    //(float) (s*(z+1.0)*0.5),
	    //(float) (s*(-z+1.0)*0.375+0.25));

	    Color3f c = color[i];
	    c.x=(float) s;
	    c.y=(float) (s*(z+1.0)*0.5);
	    c.z=(float) (s*(-z+1.0)*0.375+0.25);

        }
	
        setCoordinates(0,coord);
        setColors(0,color);
    }
    
}