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# Ray marching in Rust :rust: !
I'm currently learning Rust for fun and re-writing my [ascii-renderer](https://github.com/eug-vs/ascii-3d-renderer) from Python :python:. I'm using Ray Marching this time, here's how it looks (if you are on mobile, use desktop version of the site):
[](https://asciinema.org/a/jsDqGeMkRwLeYhVIMqNbaec0M)
You can see that Ray Marching allows for some cool stuff like smooth surface blending and proper shadowing.
## Ray marching
Usually 3d renderers use a triangular mesh to describe objects in a scene. In Python version of `ascii-renderer` I defined each object as a set of points
(i.e object is defined by a function `__contains__` that determines whether the given point is in this object). It allowed me for some cool Ray Tracing stuff, but that was just me toying around.
Behold - Ray Marching! It's a cool rendering technique where you describe your scene with a *Distance Field* - each point in this field contains a distance from that point to the scene.
Well, actually it's a *Signed Distance Field* - the distance to the object is considered negative *inside* the object, and positive *outside*.
What's cool about Ray Marching is that since the whole scene is defined with mathematical expression, I can apply any mathematical transformations to it. For example I can make an object wavy
using a `sin`, or make it repeat forever with `%` operator. Also, `SDF` allows for different ways to combine objects - I can find a `union`, `difference`, and `intersection` for free!
## Performance
Currently it's rendering 4 shapes at ~19 FPS, which is pretty bad. That's probably due to my dirty and inefficient code :laughing: - I'm nowhere near a good understanding of Rust :rust: patterns.
My goal is to render 8 shapes at 24 FPS:
- 24 FPS is OK for a human eye
- 8 distinct shapes is usually enough to create a complex scene (ray marching allows for cool tricks that can multiply amount of your shapes without performance decrease)
## Plans
- Cleanup the code and increase performance
- Build an actually usable API
- Use `ncurses` instead of just printing to `STDOUT`
- Create an `ncurses` GUI for building a scene
- Allow importing/exporting scenes in `JSON`
- Do some magic :star: and expose API to the browser using `WebAssembly`
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