Raycasting Engine

A 2.5D raycasting game engine built from scratch in C with SDL2, implementing classic techniques used in games like Doom and Wolfenstein 3D.

Demo

Features

• Pure C raycasting implementation - No external game engines
• Real-time 2.5D rendering - Wall projection with texture mapping
• Sprite rendering system - Billboard sprites with depth sorting
• Texture mapping - Multiple wall textures with transparency support
• Minimap display - Real-time overhead view with player position
• Collision detection - Grid-based world collision system
• Cross-platform - Works on macOS and Linux

Controls

• Arrow Keys - Move forward/backward, turn left/right
• ESC - Exit

Installation

Prerequisites

macOS:

brew install sdl2

Ubuntu/Debian:

sudo apt-get install libsdl2-dev

Fedora/RHEL:

sudo dnf install SDL2-devel

Building

git clone <repository-url>
cd raycasting-c
make build
./raycast

Technical Implementation

• Ray casting algorithm - Cast rays for each screen column to find wall intersections
• DDA (Digital Differential Analyzer) - Efficient grid traversal for ray-wall intersection
• Texture sampling - UV mapping for realistic wall textures
• Sprite projection - 3D to 2D transformation with distance-based scaling
• Transparency handling - Magenta color key for sprite backgrounds
• Memory management - Custom texture loading and sprite management

Architecture

src/
├── main.c          # Game loop and input handling
├── graphics.c      # SDL rendering and display
├── ray.c           # Raycasting algorithm implementation
├── player.c        # Player movement and physics
├── sprite.c        # Sprite rendering and management
├── map.c           # World map and collision detection
└── upng.c          # PNG texture loading

Credits

• PNG Loading: Uses upng by Sean Middleditch - A minimal PNG decoder library
• Graphics: SDL2 for cross-platform rendering and input handling
• Game Assets: Wolfenstein 3D textures and sprites © id Software - Used for educational purposes

Built as an educational project to understand classic 3D rendering techniques and game engine architecture.