Since there have been a number of misunderstandings, I would say that I
explained it incorrectly :( So I'll try to give more detail. You know the
saying, "A picture is worth a 1000 words". So have a look at the following
I have a texture that is 512x256, which is represented in the picture by the
outermost rectangle. This is created with glTexImage2D() at the beginning
of the program.
The main area (as designated in the picture) is approx 320 x 256. I update
that using glTexSubImage2D() with the appropriate sized QUAD.
Now, have a look at the picture. Say I want to copy the letter 'A' from the
area indicated (the offscreen font area of the texture) to the designated
area in the onscreen part of the texture. Can this be done, and if so,
Or more generally, say that the font data was in an entirely different
texture. How would I copy PIECES of it to another texture. All the
examples I've seen explain how to copying a FULL texture onto the current
one (which would work if I had a separate 8x8 texture for each character).
What I want to know is, how do you copy PART OF a texture onto another one.
And if possible, I'd like to do this in texture memory, and not have to send
the font data to the OpenGL server. In other words, the full texture has
already been sent to the OpenGL server, and I want to move parts of it onto
itself (I assume this is fast, since it doesn't involve a round-trip from
client to server).