How to make a 'procedural minimap' in UPBGE?

I want to make a minimap that is drawn procedurally in UPBGE. When a message is sent, the script tries to get an overhead or orthographic view of the entire level’s terrain, and draws it onto a plane or any kind of object, and can be zoomed in/out, similar to what is seen in quite a lot of open-world games. The map can be divided into floors as well.

On solution might be to grab the data for all the objects within a certain radius of a player, and then have other, much simpler, objects that get spawned into the minimap (probably in an overlay).

Eg if you have a few game assets that are roughly square-shaped from above, just have a flat square that can spawn in at the edge of the minimap when the player comes within a certain distance of any of those objects.

I was asking like how can I make a minimap in the style of GTA or Zelda. Those maps don’t really use textures - they draw the level dynamically, usually through the use of some sort of videotexture module. Zelda is more shaded, but GTA is more outlined.

GLSL shaders do not work for vertex objects on M1, so I’m stuck with the GPU module, which I have yet to learn.

How can I recreate that style of minimap?