Your error comes from this line initially: var direction1 = Math.atan2(ball1.velocitY, ball1.velocityX); You have ball1.velocitY (which is undefined) instead of ball1.velocityY. So Math.atan2 is giving you NaN, and that NaN value is propagating through all your calculations. This is not the source of your error, but there is something else that you might want to … Read more
To detect whether two balls collide, just check whether the distance between their centers is less than two times the radius. To do a perfectly elastic collision between the balls, you only need to worry about the component of the velocity that is in the direction of the collision. The other component (tangent to the … Read more
From Wikipedia: Studies by IBM in the 1990s suggest that computers typically experience about one cosmic-ray-induced error per 256 megabytes of RAM per month.[15] This means a probability of 3.7 × 10-9 per byte per month, or 1.4 × 10-15 per byte per second. If your program runs for 1 minute and occupies 20 MB … Read more