Does calling glBufferData create/release buffers?

Question

I'm working on a program that loads new data of a model to the graphics card using OpenGL, it then switches to rendering that one, and then removes the old data so as to create more space for other uses.

From my understanding I shouldn't be creating/releasing buffers on the fly as it can lead to memory thrashing.

Is it bad to call glBufferData frequently to add new data to the graphics card? Does this count as creating/releasing buffers?

Answer 1

If you call glBufferData with the same size and usage parameters as it was called previously, then this is effectively invalidating or "orphaning" the buffer. To do anything else, to change the size or usage, is to effectively create a new buffer.

If you aren't streaming data (uploading new data every frame or so), invalidation is not especially useful. If you're no longer using the buffer, and you haven't used it in a while, just leave it there if you're going to need buffer storage again.

And if your models use different sizes, preallocate a large buffer object and have different models use different regions from that one allocation.