Python Black Hole Raytracer
Starless is a CPU black hole raytracer in numpy suitable for both informative diagrams and decent wallpaper material.
It is still in development and will be presented on my site along with my real time black hole visualizer. Starless, instead, is not real time but offers greater functionality, performing actual raytracing (while the mentioned WebGL applet uses a precomputed lookup texture for deflection).
Features
- Full geodesic raytracing in Schwarzschild geometry
- Predicts distortion of arbitrary objects defined implicitly
- Alpha-blended accretion disk
- Sky distortion
- Dust
- Bloom postprocessing
- Completely parallel
- Easy debugging by saving masks and intermediate results as images
Dependencies
python, numpy, scipy
Textures
My textures are too heavy to put on Github. To use them in the program, you need to create a textures folder and put a bgedit.png texture for the sky (a skysphere, x = lon, y = lat) and an adisk.jpg for the accretion disk (x = angle, y = radius).
Example adisk.jpg Example bgedit.png
Texture sizes are irrelevant (these texture will never end up in the GPU). You can use your own texture names or formats by editing the source.
Texture files are not needed if rendering with modes that don't use them.
Installation
Clone with git:
$ git clone https://github.com/rantonels/starless.git
or download this zip file and extract.
How to run
Write a .scene file. Examine the provided .scenes and model your file on them.
Some options will lie under the 'lofi' and 'hifi' sections. This are respectively the rendering specs for tests and the final image.
To run a test:
$ python tracer.py -d yourscene.scene
and wait. The rendered image will be in the tests folder under the name out.png, along with some other useful images.
To run the full render, just omit the -d option. The results will still be saved in tests.
Writing .scene files
Please refer to the scenes/default.scene file for a commented overview of all options.