OK, I''ve now found 2 ways of doing billboarding. One is to use blending, the other to use alpha testing as follows :- glDisable(GL_BLENDING) glEnable(GL_ALPHA_TEST ) glAlphaFunc(GL_GREATER,0.5) Of, course, this assumes that your texture has been set-up with transparent areas having an alpha value < 0.5 ... My question is which is the best method? Obviously, I have to switch blending back on for rendering my particle system etc. However, using the above technique for billboarding means that I don''t have to pass the polygons in depth-first order ..... no sorting for me :-) Any comments ....

an alpha test is far quicker than doing blending. so if its good enuf use it instead of blending

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also to get really picky
processors tend to do the ''not equal 0'' in one opp
thus glAlphaTest(GL_NOTEQUAL,0.0);
maybe be the quickest of all (i havent tested this though)

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