I observed that, on some OpenGL drivers when texturing is enabled pixel level draw functions (glDrawPixels, glBitmap and probably the others) are textured with the active texture.
The below code draws a blue drawpixels rectangle, regardless of the pixels parameter glDrawPixels takes.
// set the first pixel color to blue
However, this is not a common behaviour.
On Windows platform,
Intel 965 draws both glBitmap and glDrawPixels as textured,
MESA (soft renderer) just draws glBitmap as textured,
ATI 4850 draws none of them as textured
I thought only primitives are textured in OpenGL. However, I could not find any documentation about this behaviour. It does not seem to be a part of a functionality with purpose maybe a bug.
Is it possible that those pixel level functions implicitly using textures to transfer data? or
Is there any idea for the usage of the textured pixels on the field?