Software rendering in 500 lines of bare C++ – tinyrenderer tutorial overview

Software rendering in 500 lines of bare C++ – tinyrenderer tutorial overview

Overview

The tinyrenderer tutorial aims to explain how modern graphics APIs such as OpenGL, Vulkan, Metal and DirectX work by implementing a simplified clone from scratch in plain C++.

Starting point

The tutorial begins with a minimal program that sets three white pixels in a 64×64 TGA framebuffer and writes the result to framebuffer.tga.

#include "tgaimage.h"

constexpr TGAColor white   = {255, 255, 255, 255}; // BGRA order
constexpr TGAColor green   = {  0, 255,   0, 255};
constexpr TGAColor red     = {  0,   0, 255, 255};
constexpr TGAColor blue    = {255, 128,  64, 255};
constexpr TGAColor yellow  = {  0, 200, 255, 255};

int main(int argc, char** argv) {
    constexpr int width  = 64;
    constexpr int height = 64;
    TGAImage framebuffer(width, height, TGAImage::RGB);

    int ax =  7, ay =  3;
    int bx = 12, by = 37;
    int cx = 62, cy = 53;

    framebuffer.set(ax, ay, white);
    framebuffer.set(bx, by, white);
    framebuffer.set(cx, cy, white);

    framebuffer.write_tga_file("framebuffer.tga");
    return 0;
}

This produces a tiny image that, when scaled, shows three white dots.

Compilation and usage

To build the renderer, clone the repository, run CMake and compile:

git clone https://github.com/ssloy/tinyrenderer.git
cd tinyrenderer
cmake -Bbuild
cmake --build build -j

The executable expects two OBJ files as arguments (e.g., a model and a floor) and writes the rendered image to framebuffer.tga:

build/tinyrenderer obj/diablo3_pose/diablo3_pose.obj obj/floor.obj

Example outputs

Running the completed renderer yields images such as a shaded African head, a demon character, a glowing Diablo model, a boggie figure and a Diablo model with SSAO‑like shading. These screenshots are shown on the tutorial page.

Community insights

  • A Rust port exists where the author implemented the renderer by hand, added a small game, pixelization shaders and chromatic aberration, and shared in‑progress screenshots.

    "I went through this a few months ago in Rust. I wrote all the code by hand, no LLMs. Then I went ahead and added a small "game" on top, plus some special effects like pixelization shaders and chromatic aberration at the edge of a flashlight."
    https://github.com/kshitijl/tinyrenderer-rs

  • One commenter noted that triangle clipping is a challenging part of building a practical software renderer and wished the tutorial covered it more thoroughly.

    "I wish we could have just one of these tutorials properly cover the concern of triangle clipping. This is the part that I struggle with the most in a software renderer."

  • Another user asked how to view the TGA files produced by the program, noting that Windows does not open them by default.

    "Ok I'm following along but how do I view the tga files that this program produces? Windows can't open them."

  • A reader mentioned that the tutorial, together with John Vince’s Mathematics for Computer Graphics, was indispensable when they wrote their own software renderer, describing the process as months of grappling with the math and debugging segmentation faults.

    "This resource, along with Mathematics for Computer Graphics by John Vince [1], was truly indispensable when I wrote my own software renderer [2]. This was long before LLMs, so the whole process took me at least a couple months - most of it trying to wrap my head around math behind computer graphics and tracking down C segmentation faults."

  • Some commenters observed that the article presents a training exercise rather than a guide to GPU programming, emphasizing that the goal is to understand how graphics libraries work internally.

    "Warning: This is a training material that loosely follows the structure of modern 3D graphics libraries. It is a software renderer. **I do not intend to show how to write GPU applications — I want to show how they work."

  • A few remarks highlighted the nostalgic appeal of software rendering, noting that even a simple CPU‑based renderer can achieve interactive frame rates with effects.

    "My biggest lesson, other than the specifics of how rendering works, was that modern CPUs are really fast: a single‑threaded CPU renderer can definitely run an interactive 3D game with some fancy special effects."

  • Discussions also touched on related resources such as the Foley‑Van Dam book and comparisons to POVRay, though no definitive answers were provided in the comments.

    "Is the Foley/Van Dam book still a go to resource for this?"
    "How does this differ from POVRay?"

These community reflections reinforce the tutorial’s value as a hands‑on way to grasp the underlying mechanics of 3D rasterization while also pointing out areas—such as triangle clipping and image‑file handling—that learners may need to explore further on their own.

Sources