Modify a text file: $/billiards.pde

$/billiards.pde

//// Billiard table, with moving balls.
//// BAM 1B30a:  Demonstrate simple class.

//// Instantiate the balls.
Ball b1=  new Ball();
Ball b2=  new Ball();
Ball b3=  new Ball();

void setup() {
  //// Setup:  600x400 (for 300x500 table).
  size(600,400);
  initialize();
}
void initialize() {
  //// Initialize 3 balls.
  b1.c=  color(255,0,0);    b1.x=100+random(100);  b1.y=100;
  b2.c=  color(255,255,0);  b2.x=100+random(100);  b2.y=130;
  b3.c=  color(0,0,200);    b3.x=100+random(100);  b3.y=160;
  // +++ Use constructors, instead.
}
void keyPressed() {
  //// "R" restarts game.
  if (key=='R') {
    initialize();
  }
}

void draw() {
  //// Table, with billiard balls.
  drawTable();
  moveBalls();
  drawBalls();
}

void  drawTable() {
  //// Draw 500x300 green light-table, with thick brown border, on tan backgroud.
  background( 200,150,100 );    // Tan floor.
  //// Table:
  fill( 100,200,100 );          // Light-green table.
  stroke( 100,50,50 );          // Brown (wood) rail.
  strokeWeight(25);
  rectMode(CORNER);
  rect(50,50, 500,300);        // Table (with rail);
  //// 6 pockets.
  drawPocket( 65,65 );
  drawPocket( 65,335 );
  drawPocket( 300,65 );
  drawPocket( 300,335 );
  drawPocket( 535,65 );
  drawPocket( 535,335 );
}
void drawPocket( float x, float y) {
  //// Draw a black pocket at (x,y).
  strokeWeight(0);
  fill(0);
  ellipse( x,y, 30,30 );
}
  
void  moveBalls() {
  //// Move each ball, based on its velocity (dx,dy),
  //// and detect hits.
  b1.move();
  b2.move();
  b3.move();
  //// Check for collisions.
  check(b1, b2);
  check(b1, b3);
  check(b2, b3);
  //// Pocket (tunnel).
  tunnel(b1);
  tunnel(b2);
  tunnel(b3);
}
void tunnel( Ball b ) {
  //// Check if ball is in pocket; if so, then tunnel it.
  //++++
}

void check( Ball p, Ball q) {
  //// Check for collisions; reverse both if hit.
  if (dist( p.x,p.y, q.x,q.y) < 10) {
    p.dx=  -p.dx;
    p.dy=  -p.dy;
    q.dx=  -q.dx;
    q.dy=  -q.dy;
    //// Eliminate "ringing" (by moving both in new direction.
    p.x += 2*p.dx;    p.y +=  2*p.dy;
    q.x += 2*q.dx;    q.y +=  2*q.dy;
  }
}
void tunnel( Ball p, Ball q) {
  //// Check for collisions; reverse both if hit.
  if (dist( p.x,p.y, q.x,q.y) < 10) {
  }
  drawPocket( 65,65 );
  drawPocket( 65,335 );
  drawPocket( 300,65 );
  drawPocket( 300,335 );
  drawPocket( 535,65 );
  drawPocket( 535,335 );
}

void  drawBalls() {
  //// Draw each ball.
  b1.show();
  b2.show();
  b3.show();
}

/////////////////  CLASSES

class Ball {
  //// Billiard ball.
  color c;
  float x=0,y=0;    // Position of this ball.
  float dx=10,dy=10;  // Velocity (pixels per frame).
  //// Methods.
  void move() {
    //// Move ball by (dx,dy)
    x=  x + dx;
    y=  y + dy;
    // Bounce off walls.
    if (x < 75) {  dx=  -dx; }
    if (x > 525) {  dx=  -dx; }
    if (y < 75) {  dy=  -dy; }
    if (y > 325) {  dy=  -dy; }
  }
  void show() {
    //// Draw at (x,y)
    fill(c);
    //--  text(c, x, y+30);
    ellipseMode(CENTER);
    ellipse(x,y, 20,20);        // Diameter is 20.
  }
}