I need to draw two different textures on the same plane. That works ok if both of textures have exact same edges, but if i try something like: 1) -1,-1,0 -1,1,0 1,1,0 1,-1,0 2) -.2,-.2,0 -.2,.2,0 .2,.2,0 .2,-.2,0 Then i got effect that different pixels are calculated "under" and other are "over" first texture, so second texture not completely overlay first one. I can solve problem adding a small number to height so second texture will float above first one (-.2,-.2,0.001 ....) but this have two another problems - i need to calculate what side second texture must be visible and if both i need to draw it twice one time with +.001 and second with -.001 .. So here is question - is any way other way to make one texture overlaying other ? I need to make that working without disabling depth test because both textures can be hidden behind another one. And making floating textures bring a lot of problems.

I'm up to drawing a wall and then drawing a alpha-blended texture over it... so i see only two ways of doing that - draw full wall and then try to overlay it using glpolygonoffset, or i will try to divide my wall to subwall so one of subwalls will have same vetrixes as alpha texture have and i think i will escape z problem that way, but that will take me to draw 5 wall polygons and one alpha so will take 3x more time....

Yes drawing subwalls worked... but i need to use exact same vertex... so i can't use for first layer vertex #1,2,3,4 and for second 2,3,4,1 ...