Zooming

what is the difference in zooming using glPixelZoom and using
glTranslatef(0.0, 0.0,zoom); where zoom can be increased and decreased?

glPixelZoom works for glDrawPixels and glCopyPixels only and is screen coordinate based. It simple scales the bitmap size.
glTranslate moves geometry in z direction. Depending on the current coordinate system’s orientation this might not even result in a zoom effect.
A real zoom effect for 3D graphics needs to be done by changing the field-of-view e.g. in the gluPerspective call.

Would gluPerspective be the best for the resolution of the image?

Originally posted by Relic:
glPixelZoom works for glDrawPixels and glCopyPixels only and is screen coordinate based. It simple scales the bitmap size.
glTranslate moves geometry in z direction. Depending on the current coordinate system’s orientation this might not even result in a zoom effect.
A real zoom effect for 3D graphics needs to be done by changing the field-of-view e.g. in the gluPerspective call.