transparency

[lee]

i'm using the transparency technique described by nate @ scuzzy.net...it works great, but i have one problem, which i know can be solved by a simple function call or something (i just don't know which one). ok here goes: i have a texture with an alpha channel. the same texture is mapped onto two rotating polygons that are right next to each other. poly 2 is behind poly 1, so i render it first. but if the camera moves and poly 1 gets behind poly 2, then the alpha channel on the texture gets confused and its silhouette can be seen. obviously this is due to the fact that i am rendering in the wrong order, but if the camera is free to move then i can't help it. i have enabled depth testing. does anyone have any ideas? if you do, please post them. thanks.

[Tim Stirling]

You will need to calculate the distance to the camera and sort the objects so the one furthest away is drawn first. With only two objects it is easy.
Back in the days before a z-buffer you would have to sort maybe as much as 10,000 polys in a quake level and use the painters algorithm to display them so that polys in front are draw in front. http://www.opengl.org/discussion_boards/ubb/smile.gif