rm-racer

This is a demo of a software raymarcher running on the CPU, which I wrote in C3.

Here the mini game is just an excuse to showcase the raymarcher, hence the inconsistency between the title screen and the game, I just did this for fun ^^

You can find the source code on GitHub.

Play it below

Examples

To make sure the mini game runs reasonably well for everyone, the WASM demo is rendered at a very low resolution and then upscaled for display.

But you can achieve much better rendering quality when running it natively on desktop, so here are a few short video examples in 1280x720:

More infos

This raymarcher is implemented with a several sort of optimizations to make it usable in realtime, especially in WASM here:

• SIMD rendering (rays are processed in packets, one lane per pixel)
• 16x16 pixel tiled rendering for good cache locality
• Multithreading, where tiles are distributed across multiple threads, with cache line aligned buffers to avoid false sharing
• Beam pass, where a first coarse pass marches a cone enclosing each tile to obtain a safe starting distance, avoiding having to retrace the beginning of the path for every pixel
• Sphere tracing over-relaxation with automatic backtracking when overshooting the surface
• Adaptive intersection threshold based on distance for fewer iterations on distant surfaces

It also features (enabled at compile time):

• Analytic anti-aliasing that uses grazing rays detected during marching to estimate edge coverage
• Temporal anti-aliasing with jitter and reprojection
• sRGB output and debanding

And for development a collection of signed distance functions, plenty of PBR shading functions, and mathematical functions for manipulating SIMD vectors of vectors.