// Learning Processing
// Daniel Shiffman
// http://www.learningprocessing.com
// Example 10-3: Bouncing ball with intersection
// Two ball variables
Ball ball1;
Ball ball2;
void setup() {
size(400,400);
smooth();
// Initialize balls
ball1 = new Ball(64);
ball2 = new Ball(32);
}
void draw() {
background(255);
// Move and display balls
ball1.move();
ball2.move();
if (ball1.intersect(ball2)) { // New! An object can have a function that takes another object as an argument. This is one way to have objects communicate. In this case they are checking to see if they intersect.
ball1.highlight();
ball2.highlight();
}
ball1.display();
ball2.display();
}
// Learning Processing
// Daniel Shiffman
// http://www.learningprocessing.com
// Example 10-3: Bouncing ball with intersection
class Ball {
float r; // radius
float x,y;
float xspeed,yspeed;
color c = color(100,50);
// Constructor
Ball(float tempR) {
r = tempR;
x = random(width);
y = random(height);
xspeed = random( -5,5);
yspeed = random( -5,5);
}
void move() {
x += xspeed; // Increment x
y += yspeed; // Increment y
// Check horizontal edges
if (x > width || x < 0) {
xspeed *= - 1;
}
// Check vertical edges
if (y > height || y < 0) {
yspeed *= - 1;
}
}
// Whenever the balls are touching, this highlight() function is called
// and the color is darkened.
void highlight() {
c = color(0,150);
}
// Draw the ball
void display() {
stroke(0);
fill(c);
ellipse(x,y,r*2,r*2);
// After the ball is displayed, the color is reset back to a darker gray.
c = color(100,50);
}
// A function that returns true or false based on whether two circles intersect
// If distance is less than the sum of radii the circles touch
boolean intersect(Ball b) {
// Objects can be passed into functions as arguments too!
float distance = dist(x,y,b.x,b.y); // Calculate distance
// Compare distance to sum of radii
if (distance < r + b.r) {
return true;
} else {
return false;
}
}
}
