I was wondering what the destination of data copied with glCopyTexSubImage2D is… is it the texture bound to the specified target (e.g. GL_TEXTURE_2D) for the currently active texture unit only?
Or does it write to multiple textures if i have multiple textures bound to TEXTURE_2D targets on multiple units?
If anyone could point me to the right part of the spec … i don’t find it 
The texture object. So the bound texture id on the currently active texture unit.
Is there something like “the (single) texture object”? I thought a texture object is simply the collective state information belonging each texture?
If you are sure that only the texture bound to the currently ACTIVE unit is affected, thats also what i would have guessed - however, could you point out to me where i can find it in the spec?
I just want to know because i didn’t fint anything …
Thanks a lot already!
This absolutely can’t be in all units. Because you can have different sizes for each texture in each unit. So this could lead to memory corruption.
Very quick research on google gave me that: http://www.opengl.org/resources/code/samples/sig99/advanced99/notes/node59.html
All texture modification operations happen to the currently active texture unit only.