This took a while, but I successfully added texture rendering to walls, alongside solid roof and floor colors.
To do this, I created my own MapTexture class which extracted pixel data from a loaded image.For each ray that fired, its final hit position was mapped to a specific pixel from that texture. (using some row and column calcuations)

Some things I also did:

• Added support for multiple wall types
• Added noclip toggle, zooming in/out controls
• Optimized shading calculations for walls
• Fixed raycasting bug dealing with negative coordinates