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Asked: 2025-05-19T00:14:19+05:30

How can I prevent my sprite from peeking through walls during movement in my Breakout clone?

I’m working on a Breakout clone, and I’ve hit a frustrating snag with my paddle movement. The issue I’m facing is that part of the paddle sprite sometimes peeks through the walls when I move it into them. I thought I had a decent approach in place to stop this from happening by checking for collisions and trying to reverse the velocity when the paddle intersects with the walls. However, it’s just not working as I expected.

Here’s what’s going on: I have a `MovePaddle` method that updates the paddle’s position based on user input. Depending on whether the left or right keys are pressed, it changes the `direction` and updates the `velocity` for the paddle accordingly. When moving, I add the calculated `velocity.X` to the paddle’s position. So far, so good. But here’s where it breaks down—I have a `CheckCollisions` method that is supposed to prevent the paddle from moving through the walls.

In this method, I check whether the paddle’s bounding box (`CollideBox`) intersects with the borders of the court (which are the walls). If there’s a collision, I try to reverse the velocity and clamp the paddle’s position to the edge of the walls. However, it seems like the clamping isn’t working properly. When I adjust the position of the paddle after a collision, it still seems to poke through the wall a bit. If I take out the clamping part, the paddle just phases through without any resistance at all, which isn’t what I want either.

I’ve looked at the values I’m using for the collision checks, and they seem reasonable. But the paddle still ends up overlapping the walls sometimes. I’m wondering if there’s something I’m missing in the way I’m handling the collision logic or if there’s a better way to implement solid walls in this case.

Has anyone else experienced something similar, or could you suggest a better method to handle the paddle’s movement in relation to the walls? Any help or insights would be much appreciated!

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    2 Answers

    1. Sounds like you’re having a tough time with the paddle collisions! This is definitely a common issue when working with collision detection and physics in games, so don’t feel too bad about it.

      From what you described, it seems like your collision detection with the walls might not be working quite right. When you check if the paddle’s collision box (`CollideBox`) intersects with the walls, it could be that the checks aren’t accounting for the whole bounding box or the position adjustments aren’t enough to correct the overlap.

      One thing to consider is the timing of your checks. Make sure that your `CheckCollisions` method is called right after the paddle’s position is updated but before the next frame renders. If you’re modifying the position based on the velocity after checking collisions, that could lead to the paddle poking through the walls.

      Another thing to look at is how you are clamping the position after detecting a collision. Instead of just reversing the velocity, try adjusting your paddle’s position explicitly based on its size. For example, if it collides with the left wall, you might want to set the paddle’s position to its width so it sits flush against the wall:

      
    if (isCollidingWithLeftWall) {
        paddle.Position.X = wallLeftEdge + paddle.Width;
    }

      Also, you could try to implement a “buffer” zone for collisions, where you check for intersections a little before the actual position reaches the wall; that might help avoid the flicker of the paddle going through just a pixel or two.

      Overall, debugging collision problems can take some trial and error. Test with various approaches to detect and resolve collisions, and you should be able to find a solution that works for you!

      Good luck, and don’t hesitate to share more details if you need further help!

    2. The issue you’re encountering arises primarily because you’re attempting to correct paddle movement after the collision has already occurred by simply reversing velocities or clamping afterward. Even minimal paddle overlaps result from updates applied before collision handling, causing visual glitches. A more reliable approach would be to proactively calculate and constrain your paddle’s new position within bounds before assigning it. Specifically, instead of positioning the paddle then checking for collisions, first compute the paddle’s proposed movement according to user input, clamp the final position within the acceptable minimum and maximum coordinates (the playable area), and only thereafter update the paddle’s position.

      For example, if you know the left and right bounds represent the playable edges, the paddle’s position update could look something like this: position.X += velocity.X; position.X = Math.Clamp(position.X, leftWall + paddleWidth / 2, rightWall - paddleWidth / 2); This ensures the paddle never penetrates the walls, as the position is restricted at precisely the correct limit before applying it. Additionally, avoid altering or inverting velocity unnecessarily upon collision, as paddle-wall boundaries don’t require velocity reversal; instead, simply halting or limiting movement at the boundary keeps interactions predictable and visually stable.