OpenGL Correctness tips

According to the OpenGL SDKs that I downloaded for use in Visual Studio
2005, the following tip is recommended:

--------------------------------------
To obtain exact two-dimensional rasterization, carefully specify both the
orthographic projection and the vertices of the primitives that are to be
rasterized. Specify the orthographic projection with integer coordinates, as
shown in the following example:

gluOrtho2D(0, width, 0, height);

The parameters width and height are the dimensions of the viewport. Given
this projection matrix, place polygon vertices and pixel image positions at
integer coordinates to rasterize predictably. For example, glRecti(0, 0, 1,
1) reliably fills the lower-left pixel of the viewport, and glRasterPos2i(0,
0) reliably positions an unzoomed image at the lower-left pixel of the
viewport. However, point vertices, line vertices, and bitmap positions
should be placed at half-integer locations. For example, a line drawn from
(x (1) , 0.5) to (x (2) , 0.5) will be reliably rendered along the bottom
row of pixels in the viewport, and a point drawn at (0.5, 0.5) will reliably
fill the same pixel as glRecti(0, 0, 1, 1).

An optimum compromise that allows all primitives to be specified at integer
positions, while still ensuring predictable rasterization, is to translate x
and y by 0.375, as shown in the following code sample. Such a translation
keeps polygon and pixel image edges safely away from the centers of pixels,
while moving line vertices close enough to the pixel centers.

glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity( );
gluOrtho2D(0, width, 0, height);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity( );
glTranslatef(0.375, 0.375, 0.0);
/* render all primitives at integer positions */
----------------------------------

To my OpenGL noob mind this means that the above procedure ensures that
primitive vertex coordinates map accurately to pixels on screen. Is this
correct?

If so, and I use the above method, I guess I'll have to issue a
glTranslatef(0.375, 0.375, 0); every time I use glLoadIdentity(); to reset a
model matrix because this cancels my 0.375 translation.

To avoid this, I suumed I could use the following so that glLoadIdentity();
will atomatically reset the origin of the coordinate system to include this
0.375 offset:

gluOrtho2D(0.375, width, 0.375, height);

but it doesn't seem to work. Should it work? Or will I simply have to do the
offset translation after any glLoadIdentoty().

Or have I missed something about this concept entirely :)


.

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