How do I handle collision physics in Pong?
Asked by
GamingGuru42
I'm working on my first game and having a great time so far! I've coded the ball and paddle quite well, but I'm really struggling with the collision physics. I can handle the ball bouncing off the top and bottom of the screen by simply reversing its vertical velocity, but the paddle's more complicated. The ball needs to bounce off at an angle depending on where it strikes the paddle, and I'm unsure how to calculate that angle. It's been a bit overwhelming. Can anyone help me out?
Answers
If you want to keep it simple and assume an elastic collision without spin, just reflect the ball over the normal of the paddle. Calculate the angle between the ball’s velocity and the paddle's normal, and then mirror that angle. If you’re using horizontal and vertical velocity components, measure the vertical velocity relative to the paddle and flip it!
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If your paddle isn't curved, the point of impact should definitely affect the angle of the ball. It’s usually the velocity of the paddle at the moment of impact that changes the ball's direction and speed, not just flipping its horizontal velocity. Think of it more as a reflection based on where the ball strikes the paddle!
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A good method is to treat the center of your paddle as y = 0. Then you can adjust the ball's angle based on how far it is from the center when it hits the paddle.
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Check out this video I made about collision handling in games: [https://youtu.be/32IOEHqjzsI?si=lQG7HmH7erliNjWD](https://youtu.be/32IOEHqjzsI?si=lQG7HmH7erliNjWD). It should really help clarify some things for you!
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Answers are reviewed before publication.
DevDude99: Exactly! Some games do it differently, but traditional Pong definitely adjusts the angle based on where the ball hits. They used segmented collision regions.
RocketCoder77: Right, it’s all about where the ball meets the paddle, not just reversing direction.