Originally posted by The Fugitive
they use the transparencies to give the site that "glowing" look
My gunsight glows, and has a translucent reticule, while only using the base texture, no alpha map. And the single texture is only the 2 colors of pure green and magenta, without any anti-aliasing between them.
Getting these effects out of a single texture appears to require that the gunsight texture be very small, and thus the reticule has to be pretty simple. You also need to keep all reticule markings only 1 pixel wide. You get these effects out of the game's inherent texture blurring and the stretching of the small texture over the larger gunsight area.
My gunsight is 32x32 and is all magenta except for 5 pure green pixels. These are arranged with 1 in the center and the other 4 arranged in a cross around this, but separated from the center pixel by 1 magenta pixel. Like this (only with more magenta going out to the 32x32 edges):
M.M.G.M.M
M.M.M.M.M
G.M.G.M.G
M.M.M.M.M
M.M.G.M.M
In the game, each green pixel appears as a translucent, glowing diamond. The whole reticule is stretched out to a decent size--you can see it on the tail turret of the B24 in my avatar pic to the left.