Software Renderer

This project is a software-based 3d renderer implemented entirely in C99. It mimics the functionality of a modern graphics api such as OpenGL, but runs fully on the CPU. The renderer is built around a modular architecture, focusing on flexibility and ease of integration.

“The Lighthouse” by Cotman Sam (used under CC BY 4.0). 15ㅤㅤㅤㅤ,000 triangles rendered in real time at ~60FPS on the AMD Ryzen 7 5800X

Features

• Complete 3d rendering pipeline: from model import to final pixel output, every stage of the pipeline is implemented in software
• Cross-platform support: includes a lightweight platform layer compatible with both windows (windows.h) and linux (x11)

Linux support is currently only partial due to hardware limitations and time constraints

• Custom asset loaders: manually written parsers for .obj and .mtl formats

• Minimal external dependencies: uses only platform libraries for window management and stb_image for texture loading

• Optimized rasterization:

  • perspective-correct interpolation for vertex attributes (color, uv coordinates)
  • back-face culling for performance
  • depth buffering (z-buffer) for proper occlusion

• Shading and texture mapping:

  • supports gouraud and flat shading
  • textured and non-textured rendering modes
  • bilinear and nearest-neighbor texture sampling

• 3d math library:

  • custom implementation for vector and matrix operations
  • left-handed coordinate system
  • column-major matrix layout for transformations

Technical Specifications

• Language: c99 (no external frameworks)

• Rendering core:

  • cpu-driven rasterizer
  • dedicated framebuffers for color and depth

• Implemented graphics pipeline stages:

  1. model & view transformation: converts object-space vertices into world and camera space
  2. projection: applies perspective projection to map 3d coordinates into 2d screen space
  3. clipping: clips primitives against the view frustum boundaries
  4. rasterization: converts triangles into pixel fragments
  5. shading & texturing: applies color interpolation or texture sampling per pixel

• Dependencies:

  • stb_image.h for texture loading
  • windows.h (on windows) or x11/xlib.h (on linux) for windowing and input handling

Showcase

Building and Running

the project includes a makefile for straightforward compilation.

1. clone the repository:

   git clone https://github.com/auria-dev/software-renderer.git
   cd software-renderer

2. build the project:

   • on linux, ensure x11 development headers are installed:

     # debian/ubuntu
     sudo apt-get install libx11-dev
     
     # arch
     sudo pacman -S libx11
     
     # nix
     nix-shell -p libX11
     
     # void
     sudo xbps-install -S libX11-devel

   • compile the source using:

     make

3. run the application:

   ./renderer

Controls

• w, a, s, d: move camera forward, left, backward, and right

• space: move camera up

• left shift: move camera down

• arrow keys: rotate camera

• escape: exit the application