Show HN: Planetary CFD on a Phone

After a trek in Nepal this year, I had a month to relax, and an idea from my trek to work on, but no computer in reach. I had been experimenting with phone IDEs though and decided to see what could be accomplished.

The end result of a month at a few hours a day using AIDE is DreamPearl (source on Github), a planetary formation simulator that does all of the plate mechanics using computational fluid dynamics (CFD). Currently working on volumetric air/water cycle.

Quick (6s) video to demonstrate. https://youtu.be/5Nv9Klqlc2M

Github link https://github.com/Araesmojo/DreamPearl

Things I like: Plate mechanics as CFD "dirt" particles - plates are defined as surface regions based on target size and then dirt flows across them like a conveyor. Models pressure, drag, and frictional acc. in non-z-locking sphere built from a split D20.

3D as 2D - CFD calculations are performed on a 3D surface with no artficial wrapping or edges, but particles are tricked into believing they are 2D by performing all operations in a tile localized frame of reference.

Shaders by parts - while the move to vertex/frag shaders opened a lot of flexibilty, they also add much complexity. My approach decouples shaders into subsegments that can be superimposed to create a full shader using lines like shaderProgram = BuildShaderFromParts( "based3d", "tex", "light" ) where each call out references only the relevant portions in a file such as "light.gg" or "tex.gg". They can be mixed and matched so that swapping "point" for "base3d" in the above example would create a floating 2d sprite instead.

Barnes-Hutt tree decomposed space and lookup in a non z-locking spherical space w multiple options for level of detail (LoD)

Useful for: using opengl on a phone, implementing a CFD code, strategy/adventure games that need a random world, examples of procedural creation that diverge from the standard perlin / voronoi noise.