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Newbie
Join Date: May 2005
Posts: 2
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Please consider this java applet
Hi all. I love to program and would like to find a place where I can shoot the shit with other programmers. I have been working on this little java applet that models gravitational interaction between massless test particles and what I call great attractors. It would be great if I could get some feedback on this thing. The code below has two programs: pMass.java and bbattractor.java, which is the applet.
//pMass.java
import java.awt.*;
public class pMass
{
public int r;
public int color;
public int x;
public int y;
public int vx;
public int vy;
public int ax;
public int ay;
public pMass(int R, int X, int Y)
{ r=R;
x=X;
y=Y;
chooseColor();
}
private void chooseColor()
{
int num=(int)(7*Math.random());
if(num==0) color=0;
else if(num==1) color=1;
else if(num==2) color=2;
else if(num==3) color=3;
else if(num==4) color=4;
else if(num==5) color=5;
else color=6;
}
public void draw(Graphics thing)
{
Color drawColor;
if(color==0) drawColor=Color.blue;
else if(color==1) drawColor=Color.cyan;
else if(color==2) drawColor=Color.magenta;
else if(color==3) drawColor=Color.orange;
else if(color==4) drawColor=Color.pink;
else if(color==5) drawColor=Color.red;
else drawColor=Color.yellow;
thing.setColor(drawColor);
thing.fillOval(x-r,y-r,2*r,2*r);
}
public int getR()
{ return r;}
public int getX()
{ return x;}
public int getY()
{ return y;}
public int vxO() //'O' as in "oh", not "zero"
{ return vx;}
public int vyO()
{ return vy;}
public void vxI(int v)
{ vx=v;}
public void vyI(int v)
{ vy=v;}
public int axO()
{ return ax;}
public int ayO()
{ return ay;}
public void axI(int a)
{ ax=a;}
public void ayI(int a)
{ ay=a;}
public void move()
{
vx+=ax;
vy+=ay;
x+=vx;
y+=vy;
}
} Here's the second part.
//bbatttractor.java
//applet of test particle and a moving great attractor
//5-19-2005
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import javax.swing.Timer;
public class bbattractor extends Applet
{
//applet
private int width=1150;
private int height=750;
private boolean valid_position=true;
//pMass objects
private int r=5;
private int attR=1;
private pMass[] mass=new pMass[10];
private pMass[] att=new pMass[1];
private int ds=5;
//animation
private Timer timer;
private Image image;
private int delay=1;
public void init()
{
setBackground(Color.black);
setSize(width,height);
addMouseListener(new AMouseListener());
timer = new Timer(delay, new AnActionListener());
timer.start();
//create non-overlapping test particles
for(int i=0; i < mass.length; i++)
{
int dx=0,x=0,dy=0,y=0;
do{
dx=width-2*r;
x=r+(int)(dx*Math.random());
dy=height-2*r;
y=r+(int)(dy*Math.random());
for(int k=0; k < i; k++)
{
if (!overlap(r,x,y,mass[k].getR(),mass[k].getX(),mass[k].getY() )) valid_position=true;
else {valid_position=false; break;}
}
}while(!valid_position);
mass[i]=new pMass(r,x,y);
//if(i==(mass.length-1)) mass[mass.length-1]=new pMass(1,x,y);
}
//positions for attractors
for(int i=0; i<att.length; i++)
{ int dx=0,x=0,dy=0,y=0;
do{
dx=width-2*attR;
x=attR+(int)(dx*Math.random());
dy=height-2*attR;
y=attR+(int)(dy*Math.random());
for(int k=0; k < i; k++)
{
if (!overlap(r,x,y,att[k].getR(),att[k].getX(),att[k].getY() )) valid_position=true;
else {valid_position=false; break;}
}
}while(!valid_position);
att[i]=new pMass(attR,x,y);
}
//assign velocities
//mass[0].vxI(1); mass[0].vyI(1);
int v;
for(int i=0; i < mass.length; i++)
{ // x-velocity
v=1+(int)(ds*Math.random());
if (Math.random() >= 0.5) v=-v;
mass[i].vxI(v);
//y-velocity
v=1+(int)(ds*Math.random());
if (Math.random() >= 0.5) v=-v;
mass[i].vyI(v);
}
for(int i=0; i<att.length; i++)
{ // x-velocity
v=1+(int)(ds*Math.random());
if (Math.random() >= 0.5) v=-v;
att[i].vxI(v);
//y-velocity
v=1+(int)(ds*Math.random());
if (Math.random() >= 0.5) v=-v;
att[i].vyI(v);
}
}
public void paint(Graphics thing)
{
for(int i=0; i < mass.length; i++) mass[i].draw(thing);
for(int i=0; i< att.length; i++) att[i].draw(thing);
thing.setColor(Color.green);
thing.drawRect(0,0,width,height);
}
public void move()
{
for(int i=0; i<mass.length; i++)
{ int dax=0,day=0;
for(int k=0; k<att.length; k++)
{ int dx=mass[i].getX()-att[k].getX();
int dy=mass[i].getY()-att[k].getY();
int rSqre=dx*dx+dy*dy;
double theta;
if(dx==0) {theta=Math.PI/2;}
else {theta=Math.atan(dy/dx);}
if(dx<=0 && dy>0) theta+=Math.PI;
if(dx<=0 && dy<0) theta-=Math.PI;
dax+=(-(int)(10000*Math.cos(theta)/rSqre));
day+=(-(int)(10000*Math.sin(theta)/rSqre));
}
mass[i].axI(dax);
mass[i].ayI(day);
}
//boundaries and particles
for(int i=0; i<mass.length; i++)
{
//walls-vertical boundaries
if(mass[i].getX() > width - mass[i].getR() && mass[i].vxO() > 0)
{ int v=(int)(ds*Math.random());
mass[i].vxI(-v-1);
v=(int)((ds)*Math.random());
if (Math.random() >= 0.5) v=-v;
mass[i].vyI(v);
}
if(mass[i].getX() < mass[i].getR() && mass[i].vxO() < 0)
{ int v=(int)(ds*Math.random());
mass[i].vxI(v+1);
v=(int)((ds)*Math.random());
if (Math.random() >= 0.5) v=-v;
mass[i].vyI(v);
}
//walls-horizontal boundaries
if(mass[i].getY() < mass[i].getR() && mass[i].vyO() < 0)
{ int v=(int)((ds)*Math.random());
mass[i].vyI(v+1);
v=(int)((ds)*Math.random());
if (Math.random() >= 0.5) v=-v;
mass[i].vxI(v);
}
if(mass[i].getY() > height - mass[i].getR() && mass[i].vyO() > 0)
{ int v=(int)((ds)*Math.random());
mass[i].vyI(-v-1);
v=(int)((ds)*Math.random());
if (Math.random() >= 0.5) v=-v;
mass[i].vxI(v);
}
}
//collisions among particles
for(int i=0;i<mass.length; i++)
{
for(int k=0;k<i;k++)
if(k!=i && overlap(mass[i].getR(),mass[i].getX(),mass[i].getY(),mass[k].getR(),mass[k].getX(),mass[k].getY()) )
{
if(mass[i].vx*mass[k].vx < 0) //horizontal direction
{ mass[i].vx=-mass[i].vx;
mass[k].vx=-mass[k].vx;
mass[i].x+=mass[i].vx;
mass[k].x+=mass[k].vx; //move one particle away to prevent prolonged collision
}
else if( mass[i].vx*mass[i].vx >= mass[k].vx*mass[k].vx )
{ mass[i].vx=-mass[i].vx; //same direction; switch velocities
mass[i].x+=mass[i].vx;
mass[k].x+=mass[k].vx;
}
else
{ mass[k].vx=-mass[k].vx;
mass[i].x+=mass[i].vx;
mass[k].x+=mass[k].vx;
}
if(mass[i].vy*mass[i].vy < 0) //vertical direction
{ mass[i].vy=-mass[i].vy;
mass[k].vy=-mass[k].vy;
mass[i].y+=mass[i].vy;
mass[k].y+=mass[k].vy;
}
else if( mass[i].vy*mass[i].vy >= mass[k].vy*mass[k].vy )
{ mass[i].vy=-mass[i].vy; //same direction; switch velocities
mass[i].y+=mass[i].vy;
mass[k].y+=mass[k].vy;
}
else
{ mass[k].vy=-mass[k].vy;
mass[i].y+=mass[i].vy;
mass[k].y+=mass[k].vy;
}
}
}
//boundaries and attractors
for(int i=0; i<att.length; i++)
{
//walls-vertical boundaries
if(att[i].getX() > width - att[i].getR() && att[i].vxO() > 0)
{ int v=(int)(ds*Math.random());
att[i].vxI(-v-1);
v=(int)((ds)*Math.random());
if (Math.random() >= 0.5) v=-v;
att[i].vyI(v);
}
if(att[i].getX() < att[i].getR() && att[i].vxO() < 0)
{ int v=(int)(ds*Math.random());
att[i].vxI(v+1);
v=(int)((ds)*Math.random());
if (Math.random() >= 0.5) v=-v;
att[i].vyI(v);
}
//walls-horizontal boundaries
if(att[i].getY() < att[i].getR() && att[i].vyO() < 0)
{ int v=(int)((ds)*Math.random());
att[i].vyI(v+1);
v=(int)((ds)*Math.random());
if (Math.random() >= 0.5) v=-v;
att[i].vxI(v);
}
if(att[i].getY() > height - att[i].getR() && att[i].vyO() > 0)
{ int v=(int)((ds)*Math.random());
att[i].vyI(-v-1);
v=(int)((ds)*Math.random());
if (Math.random() >= 0.5) v=-v;
att[i].vxI(v);
}
}
//collisions among attractors
for(int i=0;i<att.length; i++)
{
for(int k=0;k<i;k++)
if(k!=i && overlap(att[i].getR(),att[i].getX(),att[i].getY(),att[k].getR(),att[k].getX(),att[k].getY()) )
{
if(att[i].vx*att[k].vx < 0) //horizontal direction
{ att[i].vx=-att[i].vx;
att[k].vx=-att[k].vx;
}
else if( att[i].vx >= att[k].vx ) att[i].vx=-att[i].vx; //same direction; switch velocities
else att[k].vx=-att[k].vx;
if(att[i].vy*att[i].vy < 0) //vertical direction
{ att[i].vy=-att[i].vy;
att[k].vy=-att[k].vy;
}
else if( att[i].vy >= att[k].vy ) att[i].vy=-att[i].vy; //same direction; switch velocities
else att[k].vy=-att[k].vy; }
}
//collissions between particles and attractors
for(int i=0;i<mass.length; i++)
{
for(int k=0;(k<i && k<att.length);k++)
if(k!=i && overlap(mass[i].getR(),mass[i].getX(),mass[i].getY(),att[k].getR(),att[k].getX(),att[k].getY()) )
{
mass[i].y=-(int)(height/2*Math.random());
mass[i].x=-(int)(width*Math.random());
}
}
//move particles
for(int i=0;i<mass.length; i++) mass[i].move();
//move attractors
for(int i=0;i<att.length; i++) att[i].move();
}
private boolean overlap(int r1, int x1, int y1, int r2, int x2, int y2)
{
int d=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
return (d <= (r1+r2)*(r1+r2));
}
private class AMouseListener implements MouseListener
{
public void mouseClicked(MouseEvent e)
{
if (timer.isRunning()) timer.stop(); else timer.start();
}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {}
}
private class AnActionListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
move();
repaint();
}
}
}
Feel free to change the number of test particles, great attractors, and dimensions of the display.
Thanks. |
May 27th, 2005, 12:19 AM
Threaded Mode