particlesystem.java

thq 发布的《worms》 motorola 源代码

import java.util.Random;
import javax.microedition.lcdui.Graphics;

public class ParticleSystem
{

    public static final int STATE_LEFT = 0;
    public static final int STATE_RIGHT = 2;
    public static final int STATE_NONE = 3;
    private int windFactor;
    private int nParticles;
    private int positionX[];
    private int positionY[];
    private Random random;
    private Imp particle;

    public ParticleSystem(Landscape landscape)
    {
        random = new Random();
        nParticles = 0;
        if(Landscape.type == 0)
        {
            nParticles = 30;
            positionX = new int[nParticles];
            positionY = new int[nParticles];
            particle = new Imp("/particle_snow.png", 1);
            for(int i = 0; i < nParticles; i++)
            {
                positionX[i] = Math.abs(random.nextInt()) % 300;
                positionY[i] = Math.abs(random.nextInt()) % 150;
            }

        } else
        if(Landscape.type == 2 || Landscape.type == 3)
        {
            nParticles = 15;
            positionX = new int[nParticles];
            positionY = new int[nParticles];
            particle = new Imp("/particle_leaf.png", 1);
            for(int j = 0; j < nParticles; j++)
            {
                positionX[j] = Math.abs(random.nextInt()) % 300;
                positionY[j] = Math.abs(random.nextInt()) % 150;
            }

        }
    }

    public void setWind(int i)
    {
        windFactor = i;
    }

    public void runFrame()
    {
        for(int i = 0; i < nParticles; i++)
        {
            if(Landscape.type == 0)
            {
                if(windFactor < 0)
                    positionX[i] += (Math.abs(random.nextInt()) & 0x7) - 4 - 2;
                else
                    positionX[i] += ((Math.abs(random.nextInt()) & 0x7) - 4) + 2;
            } else
            if(Landscape.type == 2 || Landscape.type == 3)
                if(windFactor < 0)
                    positionX[i] += (Math.abs(random.nextInt()) & 0x7) - 4 - 4;
                else
                    positionX[i] += ((Math.abs(random.nextInt()) & 0x7) - 4) + 4;
            positionY[i] += Math.abs(random.nextInt()) & 0x3;
            if(positionY[i] > 150)
            {
                positionX[i] = Math.abs(random.nextInt()) % 300;
                positionY[i] = -5;
            }
        }

    }

    public void paint(Graphics g)
    {
        for(int i = 0; i < nParticles; i++)
        {
            particle.setPosition(positionX[i] + Landscape.levelX, positionY[i] + Landscape.levelY);
            particle.setFrame(((particle.curFrame++ >> 1) + 1) % particle.frameCount);
            particle.paint(g);
        }

    }
}