I'm trying to create a cummulative effect in which new data is added to the framebuffer on each frame.
Ideally I would like to render the first frame to a texture and then use this texture as the background for the next, add the 2nd frame to it and so on...

Doe anybody know if this is possible using (only) vertex/fragment shaders in WebGL? I guess I can probably read back the texture and download it again, but I expect to have some performance issues doing this.

Thx !