NYUSH2020S_5_arrays.pde

/* IxLab 2020S -  NYU Shanghai
 *  recorded to introduce concepts 
 *  Ideas for exercises to practice: 
 *  Add a third ball bouncing
 *  Make the size different for dif. balls
 *  Make the color different for dif. balls
 */


float[] x;        //position of the ball 1
float[] y;        //position of the ball 2
float spdX1, spdY1;  //speed of the ball 1
float spdX2, spdY2;  //speed of the ball 2
float spdX3, spdY3;  //speed of the ball 2
color c1, c2, c3;           //colors of the balls
int d = 20;

void setup() {
  size(400, 400);
  x = new float[3];
  y = new float[3];
  for (int i=0; i<2; i++) {
    x[i] = random(width);
  //  y[i] = random(height);
  }
  y[0] = random(height);
  y[1] = random(height);
  y[2] = random(height);


  noStroke();
  spdX1 = random(-10, 10);
  spdY1 = random(-10, 10);
  spdX2 = random(-10, 10);
  spdY2 = random(-10, 10);
  spdX3 = random(-10, 10);
  spdY3 = random(-10, 10);
}

void draw() {
  background(125);

  x[0]  =  x[0]  + spdX1;
  x[1]  = x[1]  + spdX2;
  x[2]  = x[2]  + spdX3;

  y[0]  = y[0]  + spdY1;
  y[1]  = y[1]  + spdY2;
  y[2]  = y[2]  + spdY3;

  if ((x[0]  > width-d/2) || (x[0]  < d/2)) {  // x is too big
    spdX1 *= -1;  // spdX = -spdX;
  }
  if ((x[1]  > width-d/2) || (x[1]  < d/2)) {  // x is too big
    spdX2 *= -1;  // spdX = -spdX;
  }
  if ((x[2]  > width-d/2) || (x[2]  < d/2)) {  // x is too big
    spdX3 *= -1;  // spdX = -spdX;
  }


  if ((y[0]  > height-d/2) || (y[0]  < d/2)) {  // x is too big
    spdY1 *= -1;
  }
  if ((y[1]  > height-d/2) || (y[1]  < d/2)) {  // x is too big
    spdY2 *= -1;
  }
  if ((y[2]  > height-d/2) || (y[2]  < d/2)) {  // x is too big
    spdY3 *= -1;
  }

  fill(c1);
  ellipse (x[0], y[0], d, d);
  fill(c2);
  ellipse (x[1], y[1], d, d);
  fill(c3);
  ellipse (x[2], y[2], d, d);
}

void mousePressed() {
  c1 = color(random(0, 255), random(0, 255), random(0, 255));
  c2 = color(random(0, 255), random(0, 255), random(0, 255));
}

void keyPressed() {
}