love2d renderplanet demo

This project demonstrate the 2D planet rendering technique described at https://habrahabr.ru/post/248381/ (Russian).

I google translated the article to English and followed the instructions as best as I can, with the difference being I used shaders for the atmosphere and shadow instead of using a translucent image.

texture_template.png is orthographic projection encoded into an image.

http://mathworld.wolfram.com/OrthographicProjection.html

It is generated using generate-template.lua.

All the earth textures are equirectangular projection and the rendering algorithm assumes this too.

https://en.wikipedia.org/wiki/Equirectangular_projection

You can find more planet texture data from NASA.