David Megginson writes: > > Feel free to play with the sample tree and to compare it to the > non-billboarded tree. I don't know which approach would be better for > an entire forest: > 1. The non-billboarded tree has 18 vertices (or so), but doesn't require any special dynamic transformation. > >2. The billboarded tree has only 4 vertices, but requires a > transformation based on the view matrix. > >Norm: which do you think would be more efficient for a forest of, say, >500 trees?
David One of the ideas behind the 'impostor' is that the transform is allready applied to the texture so that unless the 'impostor' needs updating the 'impostor' only needs the 4 vertex calls. Because it is relatively expensive to rerender the 'impostor' only those trees beyond 'some distance' are considered as impostor candidates. IMHO This occasionally recreating the impostor texture and then applying ONLY a texture mapped quad will be significantly faster then either of your 'possibilities' above when using an appropriate 'impostor distance' Note that Impostor textures can be a shared resource too :-) Norman _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
