jarble

//I wish there were a better way to do this!
#define func(type,name,param1,param2,body) type name(type param1,type param2) {body}
#define generic(name,param1,param2,body) func(float,name,param1,param2,body) func(vec2,name,param1,param2,body) func(vec3,name,param1,param2,body) func(vec4,name,param1,param2,body)

//define two "generic" functions using this macro
generic(add,a,b,
    return a + b;
)

generic(sub,a,b,

Domiii

--[[
Steps:

1. Download heightmap Bitmap
    e.g. from terrain.party: http://terrain.party/api/export?name=guarda&box=10.186055,46.850130,10.080975,46.778264)
    e.g. from earthe
      Data Sets: NASA LPDAAC Collections -> NASA SRTM (SRTM 3) Collections
2. Use this site to convert BMP to Lua: https://codepen.io/Domiii/pen/oMJvoJ?editors=0010
3. Copy the final Lua code to workspace.TerrainPixels (ModuleScript)
4. Run this script!