gsalvadoi/guinxu-engine

guinxu-engine is a 3D software renderer written in C++ as a learning project. A software renderer is a program that draws 3D graphics entirely through calculations in code, without relying on a GPU or graphics card hardware to do the work. This makes it a useful exercise for understanding exactly how 3D rendering works at a fundamental level. The project is built using SDL2, a library that handles creating a window and drawing pixels to it. On top of that foundation, the author implemented all the standard building blocks of 3D rendering by hand. These include drawing lines and triangles, projecting 3D coordinates onto a 2D screen, handling transforms like moving, rotating, and scaling objects, and a Z-buffer which tracks depth so that closer objects correctly cover objects behind them. The renderer also supports loading 3D model files in the OBJ format, applying textures to surfaces, basic lighting using a technique called Lambert diffuse shading, specular reflections using the Phong model, and a free-moving camera you control with WASD keys. There are two triangle-filling modes: one that uses barycentric coordinates and one that applies perspective-correct texture interpolation, which fixes a visual distortion that simpler affine interpolation produces. You can toggle the Z-buffer visualization while the program is running. The README is brief and the project is explicitly described as a self-learning exercise rather than a production tool or library. It includes a simple original test character for demonstrating the lighting and rendering features.