Usage
<applet code="AbstractSpace.class" width="400" height="400">
<param name="speedx" value="2"></param>
<param name="speedy" value="2"></param>
<param name="angrot" value="-5"></param>
<param name="stramt" value="800"></param>
</applet>
Source Code
// Abstract space
// Copyright (C) 2002 Charles Foster
// Please visit www.cfoster.net
import java.awt.*;
import java.applet.*;
public class AbstractSpace extends Applet implements Runnable
{
double[][] stars;
double centerx, centery;
Thread myThread = null;
Image myImage = null;
Graphics g2;
boolean clicked = false;
boolean credits = true;
double speedx = 0.02, speedy = 0.02, angrot = 0.05;
double oldx = 0, oldy = 0;
int stramt, j;
public void init()
{
centerx = (int)size().width/2;
centery = (int)size().height/2;
getParameters();
for(int i=0;i<stars.length;i++)
{
buildStar(i);
}
myImage = createImage(size().width,size().height);
g2 = myImage.getGraphics();
g2.setFont(new Font("Helvetica", Font.BOLD, 12));
}
public void getParameters()
{
speedx=(double)(Integer.parseInt(getParameter("speedx")))/100;
speedy=(double)(Integer.parseInt(getParameter("speedy")))/100;
angrot=(double)(Integer.parseInt(getParameter("angrot")))/100;
stramt = Integer.parseInt(getParameter("stramt"));
stars = new double[stramt][6];
}
public void buildStar(int s)
{
stars[s][0] = 0;
stars[s][1] = 0;
stars[s][2] = 0;
stars[s][3] = 0;
stars[s][4] = Math.random()*360; // angle to start
stars[s][5] = Math.random()*size().width*2; // life expectancy
}
public void start()
{
if(myThread == null)
{
myThread = new Thread(this);
myThread.start();
}
}
public void stop()
{
if(myThread != null)
{
myThread.stop();
myThread = null;
}
}
public void run()
{
while(true)
{
g2.setColor(Color.black);
g2.fillRect(0,0,size().width,size().height);
if(credits)
{
g2.setColor(Color.green);
g2.drawString(
"Abstract Space, Copyright (C) Charles Foster 2002",20,20);
g2.drawString("www.cfoster.net",20,35);
if(++j > 400) { credits = false; }
}
g2.setColor(Color.white);
for(int i=0;i<stars.length;i++)
{
stars[i][0] =
Math.cos(oldx+stars[i][4])*stars[i][2]*180/Math.PI+centerx;
stars[i][1] =
Math.sin(oldy+stars[i][4])*stars[i][3]*180/Math.PI+centery;
if(!clicked)
{
if(stars[i][0] > stars[i][5]) { buildStar(i); }
stars[i][2] += speedx;
stars[i][3] += speedy;
stars[i][4] += angrot;
}
g2.fillRect((int)stars[i][0],(int)stars[i][1],2,2);
}
repaint();
try { myThread.sleep(25); } catch(InterruptedException e) {}
}
}
public boolean mouseDrag(Event evt,int x,int y)
{
clicked = true;
oldy = (double)(y-oldy)/180*Math.PI;
oldx = (double)(oldx-x)/180*Math.PI;
return true;
}
public boolean mouseUp(Event e, int x, int y)
{
clicked = false;
return true;
}
public void paint(Graphics g){}
public void update(Graphics g)
{
paint(g2);
g.drawImage(myImage, 0, 0, this);
}
}