Line Anti-aliasing
By: Akbar A.( syedali011@earthlink.net)
June 13, 2000 In this paper we are going to be talking about line anti-aliasing and what it is, and how to get rid of it. If you have been making graphical applications for a little while you will start to notice "lines" or as we call them jaggies. These jaggies are most apparent when the lines are nearly horizontal of nearly vertical. jaggies are seen with lines. you will be able to tell if it is a jaggie if you can see "pixels" that are not supposed to be part of the line.
Although i could explain to you how and why these happens (has to do with the line algorithm and where it decides to draw the next pixel in a line) but i am not going to get into the details.
a video board is not like the "real world". the computer world is a finite world therefore we have to take quite a few assumptions . One of these assumptions is drawing lines.
to combat this problem. usually a graphics api will supply a function in which you can set it so that it automatically will apply the anti aliasing sub routine on all the lines.
for OpenGL this function is
glEnable(GL_LINE_SMOOTH) and as for points it is
glEnable(GL_POINT_SMOOTH)
usually when you would enable line anti aliasing you are going to want to be in a blend mode.
most developers prefer the blend  mode
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
and if you have read in your models with color data on each vertex it is better to go with
glBlendFunc(GL_SRC_ALPHA, GL_ONE)
your best bet is just to experiment with them.