you can write 100% of the code on the gpu. but that's impractical to work with. i did that here to see how fast webgl can go, since javascript is so slow https://www.youtube.com/watch?v=UNX4PR92BpI
for this bunnymark i have 1 VBO containing my 200k bunnies array (just positions). and 1 VBO containing just the 6 verts required to render a quad. turns out the VAO can just read from both of them like that. the processing is all on the CPU and just overwrites the bunnies VBO each frame
for this bunnymark i have 1 VBO containing my 200k bunnies array (just positions). and 1 VBO containing just the 6 verts required to render a quad. turns out the VAO can just read from both of them like that. the processing is all on the CPU and just overwrites the bunnies VBO each frame