You should be able to batch CPU-side drawcalls by packing multiple meshes into bigger vertex buffer, then generating draw parameters for every object into SSBO/UBO, and then utilizing ARB_multi_draw_indirect to draw everything at once. To change textures inside these batched drawcalls you might need ARB_bindless_texture. This talk is helpful: https://www.gdcvault.com/play/1020791/Approaching-Zero-Drive...

I don't know if these extensions are available on Pi driver, though.

I am a developer but you guys are speaking a foreign language from my perspective in this thread. Where can I learn about graphical programming for the Pi, or are you guys well versed in game programming in general and applying it here? Sounds like an interesting skill set and challenge

https://antongerdelan.net/opengl/ is a decent resource for learning opengl (the author was a TA in my graphics course in college :D). And I do think it's worth Lear ing opengl over vulkan today. Vulkan dials the api complexity up to 11. If you're happy with windows only, then directx 11 would be a good choice too, but I don't have a good reference off hand.

The problem with graphics programming is that really you need to learn two things simultaneously: how 3d graphics are rendered, and how to use a GPU api. They can both be a significant thing to learn alone, and the complexity of cramming the two into your brain together makes things hard.

Seconded, I too would like resources to learn more about this topic. Spend most of my time with business logic.

Try out an introductory OpenGL tutorial. There are many out ther. Just drawing a square will be a good lesson