I have a 16bit RGB565 texture already allocated. I have pixel data in the same format, same color depth that I want to copy to the texture.
(512 x 512)
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, data);
takes .08 to .1 seconds(!) just to copy a 400 x 300 pixel area.
This seems to be incredibly slow. Is there a trick I'm missing? Is a different format or a different way of doing this that is faster?