bouncing

bounce2.pde

/*
a thing bouncing in a box
 */

int radius = 5;
PVector ballPos;
PVector ballVel;
float boxW, boxH;
float boxX, boxY;
float r, g, b;
color ballCol;


void setup() {
  size(300, 200);
  background(0);
  makeBox();
}

void makeBox() {
  r = random(255);
  g = random(255);
  b = random(255);
  boxW = random(40, 150);
  boxH = random(40, 150);
  boxX = random(width-boxW);
  boxY = random(height-boxH);
  ballCol = color(r, g, b);
  ballPos = new PVector(random(boxX+radius, (boxX+boxW)-radius), random(boxY+radius, (boxY+boxH)-radius));
  ballVel = new PVector(random(1, 3), random(1, 3));
}

void draw() {
  background(0);
  stroke(255);
  fill(0);
  rectMode(CORNER);
  rect(boxX, boxY, boxW, boxH);
  ballPos.add(ballVel);
  if (ballPos.x-radius <= boxX || ballPos.x+radius >= boxX+boxW) {
    ballVel.x *= -1;
  }
  if (ballPos.y-radius <= boxY || ballPos.y+radius >= boxY+boxH) {
    ballVel.y *= -1;
  }
  stroke(ballCol);
  fill(ballCol);
  ellipse(ballPos.x, ballPos.y, 2*radius, 2*radius);
}

void mousePressed() {
  makeBox();
}