Question

Do I have to generate and bind a framebuffer for every renderbuffer I create?
Or is there a chance to create renderbuffer only (and map it to a texture or submit somehow to the sahders)?

I just want to render to a one channel buffer to create some mask for later use. I think setting up a complete framebuffer would be overhead for this task.

Thanks.

Answer 1

A renderbuffer is just an image. You cannot bind one as a texture; if you want to create an image to use as a texture, then you need to create a texture. That’s why we have renderbuffers and textures: one of them is for things that you don’t intend to read from.

Framebuffers are collections of images. You can’t render to a rendebuffer or texture; you render to the framebuffer, which itself must have renderbuffers and/or textures attached to them.

You can either render to the default framebuffer or to a framebuffer object. The images in the default framebuffer can’t be used as textures. So if you want to render to a texture, you have to use a framebuffer object. That’s how OpenGL works.

“setting up a complete framebuffer” may involve overhead, but you’re going to have to do it if you want to render to a texture.