gluPerspective, glViewport, gluLookAt and the GL_PROJECTION and GL_MODELVIEW Matricies

Question

Original Question

I want to use \'gluPerspective\', \'glViewport\' and \'gluLookAt\' to manipulate my camera and screen.

Which functions to I apply to which

Answer 1

I define my reshape callback function as:

Call glViewport(...) once in the beginning.

Then reload the projection matrix with an identity matrix:

glMatrixMode(GL_PROJECTION);
glLoadIdentity();

Then:

glPerspective(...)
glMatrixMode(GL_MODELVIEW);

gluLookAt(...) can be called anytime later if you need to change your camera position.

Works for my simple purposes.