Raycast

A classic raycasting engine written in Rust, implementing a Wolfenstein 3D-style first-person renderer from scratch.

Features

• DDA Raycasting Algorithm: Uses Digital Differential Analysis for efficient wall collision detection
• Real-time Rendering: 320x200 resolution scaled up 3x, rendered at 60fps using GPU-accelerated pixel buffers
• First-Person Controls: WASD or arrow keys to navigate the maze
• Distance Shading: Walls darken with distance for depth perception
• Side Shading: Different wall orientations (N/S vs E/W) render with different brightness for visual clarity
• Collision Detection: Player cannot walk through walls (axis-aligned sliding)

How It Works

Architecture

main.rs       → Window creation via winit, event loop, input handling
map.rs        → Static 8x8 maze layout, wall query function
player.rs     → Player position/angle state, movement with collision
raycast.rs    → DDA (Digital Differential Analysis) ray-wall intersection
render.rs     → Frame buffer rendering: ceil, floor, wall columns, shading

Raycasting Pipeline

1. For each horizontal pixel column (0 to 319):

   • Calculate ray angle within a 60° FOV
   • Cast ray using DDA algorithm to find nearest wall
   • Compute perpendicular distance (avoids fisheye distortion)

2. Draw vertical wall column:

   • Height = viewport_height / perpendicular_distance
   • Color shaded by distance and wall side (E/W walls are darker)

3. Background:

   • Ceiling: dark blue (#202030)
   • Floor: dark olive (#303020)

DDA Algorithm

The raycaster steps through grid cells incrementally, comparing accumulated side distances (side_dist_x vs side_dist_y) to determine which wall face is hit first. This guarantees finding the closest wall intersection without testing every cell.

Rendering

Uses the pixels crate for a simple GPU-accelerated frame buffer. The frame is an RGBA byte array (320×200×4 bytes), updated each frame and displayed via winit's windowing system.

Building

cargo build

Running

cargo run

Controls

Key	Action
W / ↑	Move forward
S / ↓	Move backward
A / ←	Turn left
D / →	Turn right
Escape	Quit

Map

The default map is an 8×8 grid with a central pillar structure:

########
#......#
#..##..#
#......#
#......#
#..##..#
#......#
########

• # = wall
• . = empty space

Edit src/map.rs to create your own layouts.

Dependencies

• winit 0.30 - Cross-platform window creation and input
• pixels 0.17 - Simple GPU-accelerated 2D pixel renderer

License

This project is for educational purposes - a hands-on exploration of raycasting fundamentals in Rust.