How to render realistic planets in love2d

[appleide]

screenshot.png (427.08 KiB) Viewed 19300 times

It rotates, and has a shadow, atmosphere, cloud layer. The above screenshot runs at 1024 * 768, with highdpi = true on 2016 Macbook.

I stumbled across a Russian article on how to render realistic 2D planets (https://habrahabr.ru/post/248381/). I couldn't find an english version of the article and had to read the google translated version and it took some time to understand, so I thought I might implement it and share it with you all. I hope you will find this useful.

renderplanet.love

(2.1 MiB) Downloaded 637 times

Github URL:
https://github.com/meric/renderplanet/

Please ask any questions you might have!

[MicroMacro]

This is awesome! Great work!

[Jack5500]

absolutly great. I don't know the impact on the performance though. How hard, performance wise, would it be to render more than 10 of those?

[raidho36]

It's a very simple shader so I imagine very little. It creates a matrix in runtime instead of using one through a uniform, so that can be optimized.

[appleide]

Thanks!

It's a very simple shader so I imagine very little. It creates a matrix in runtime instead of using one through a uniform, so that can be optimized.

Your suggestion led me to cache the atmosphere in the canvas to greatly improve performance - it was capped at 30 fps for 12 planets with highdpi = false, now performance is more than doubled.

absolutly great. I don't know the impact on the performance though. How hard, performance wise, would it be to render more than 10 of those?

With the atmosphere caching optimisation, on a 2016 MacBook it can do 80-90 frames per second for 12 earths, highdpi=false, and 60-70 frames per second for 12 earths, highdpi=true, each earth with its own shader.

After these optimisations I think rendering 10 or 12 is fine, but before, there was no more room performance-wise for rendering other assets. Thanks to raidho36 for his suggestion.

I updated the attachments in the first post.

[DIEHARD25]

Wow! Nice stuff! Great work!

p.s. here is a similar solution with more precise colours, author use 16-bit adresses to code colour grades, not sure is it suitable for LOVE 2D, but provide more variety in colour grades (up to 512 in total number of grades, if i not mistake)
sorry, still from Habr and in Russian, but with lots of code
link

[Ref]

23 fps on 10 year old pc.
Earth still rotating the wrong direction.

[raidho36]

Also I think you can compute planet coordinates programmatically, that would reduce texture bandwidth. May be more expensive though. Texture maps to flattened sphere by sine and cosine, reverse would be arcsine and arccosine.

[appleide]

23 fps on 10 year old pc.
Earth still rotating the wrong direction.

Not very realistic, is it?! I've updated the github repository so it rotates correctly. Thanks!

[Tanner]

Also I think you can compute planet coordinates programmatically, that would reduce texture bandwidth. May be more expensive though. Texture maps to flattened sphere by sine and cosine, reverse would be arcsine and arccosine.

Yep! If you save them in a mesh it's probably faster for initial load and per render. I haven't benchmarked but I have created a 2d mesh with spherish uvs. https://gist.github.com/TannerRogalsky/ ... 01aa646d29