How to use MODEL VIEW MATRIX in OpenGL

Logically, one must construct the model (in global coordinates) first.
-- Then one chooses the eye coordinates (setting up the camera.

Since these 2 coordinate transformations are included into the MODEL VIEW MATRIX, this is typically the FIRST thing to do:

glMatrixMode(GL_MODEL_VIEW); glLoadIdentity(); glLookAt(0.0,0.0,3.0, 0.0,0.0,0.0, 0.0,1.0,0.0);

-- Here, we position the camera on the z-axis (at (0,0,3)). It is pointed at the origin, with Upvector (0,1,0).
-- Here, as is typical, we leave the matrix mode in GL_MODEL_VIEW (as default mode).

It is important to realize that the eye coordinate (as a default) to looking down the negative z-axis of the global coordinate system.

CONVENTION: the global coordinates is a right-hand system.
-- in diagrams, the z-axis comes out of the plane of the page and the y-axis points upwards in the page.