I am writing a simple game in Processing in order to try to learn a bit more about it. I have an enemy class and a polygon which is drawn at the mouse coordinates to represent the player, but I was wondering how I would work out collisions, or if there are any commands in processing to deal with this sort of thing. Can anyone help? Here's the code:

//Simple game test
//Last updated 28.05.05


int amtFoes = 10;
Enemy[] foes;
int maintimer;

void setup()
{

 noCursor();
 smooth();

 size(300,200);
 background(20,20,45);
 framerate(60);
 
 foes = new Enemy[amtFoes];
 
 for(int i=0; i<amtFoes; i++)
 {
   int index = i;
   foes[index] = new Enemy((i*25)+35, 10, 0, false);
 }
 
}

void draw()
{

 background(20,20,45);
 
 for(int i=0; i<amtFoes; i++)
 {
 foes[i].update();
 foes[i].drawtoscreen();
 }
 
 fill(140,150,210,180);
 beginShape(POLYGON);
   vertex(mouseX,mouseY);
   vertex(mouseX+10,mouseY+15);
   vertex(mouseX,mouseY+10);
   vertex(mouseX-10,mouseY+15);
 endShape();
 
 if(maintimer<millis()) {
 for(int i=0; i<amtFoes; i++)
 {
   int index = i;
   foes[index] = new Enemy((i*25)+35, random(-10,-50), random(9.25,9.55), false);
 }
 maintimer = maintimer + 5000;
 }

}

class Enemy
{

 float x,y;
 float dir;
 boolean dead;
 int shottmr;
 
 Enemy(float cx, float cy, float cdir, boolean cdead)
 {
   x = cx;
   y = cy;
   dir = cdir;
   dead = cdead;  
 }
 
 void update()
 {
     
   x = x + sin(dir)*1.8;
   y = y - cos(dir)*1.8;
 
 }
 
 void drawtoscreen()
 {
 
   fill(200,180,120,150);
   stroke(255,255,255);
   ellipse(x,y,20,20);
 
 }

}

class EnemyBullet
{

 float x,y;
 int speed;
 
 EnemyBullet(float bx, float by, int bspeed)
 {
   x = bx;
   y = by;
   speed = bspeed;
 }

}

Ps. Have I posted this in the right section?