Ball to Ball Collision - Detection and Handling

Question

With the help of the Stack Overflow community I\'ve written a pretty basic-but fun physics simulator.

Answer 1

Improving the solution to detect circle with circle collision detection given within the question:

float dx = circle1.x - circle2.x,
      dy = circle1.y - circle2.y,
       r = circle1.r + circle2.r;
return (dx * dx + dy * dy <= r * r);

It avoids the unnecessary "if with two returns" and the use of more variables than necessary.