Partial rendering in FBO


Is it possible to render just a small part of a scene, for example a line, into a frame buffer object without copying each fragment?

I wish to use a single buffer for numerical computation: I want to read and write in the same buffer (there is no ressource conflict in my algorithm) without copying the whole viewport each time as to reduce my algorithm’s complexity.

If I understand your question correctly, you have 2 FBOs and you want to copy some of the contents of one into the other. To my knowledge, there is no way to copy directly from one texture to the other. Here is a thread with some solutions