Ray Tracer – How do I fix fish eye effect on side walls?

I’ve come here because I can’t seem to find out what’s wrong with my ray tracer.

I fixed the fish eye effect when looking straight on at walls, but the effect remains when the player is looking at walls to the side.

I think it’s because most of the rays hit the surface close to the player, while fewer and fewer rays hit more distant walls, resulting in a curve. The only problem is I don’t know how to make it appear linear.

    float dist = distance*cos(angle); //fix distorted distance     float rat = (depth-(dis))/depth; //calculate ratio for wall height     float h = 64*rat; //calculate height     PImage slice = sprites[0].get((int)(inter/2),0,1,16); //get image slice     image(slice,i*4,768-h/2,4,h); //display image slice 

In this example, the top screen is the raw data while the bottom screen it the ray traced 2.5D image. I’ve made the rays visible.

enter image description here