Clipmap Questions

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Jonas Andersson (jonasa++at++cs.umu.se)
Mon, 3 Nov 1997 19:01:21 +0100 (MET)


Hi performers!

I am using Performer 2.1 on a Onyx2 iR and
have a problem regarding texture coordinates for a clipmap.

Problem 1:
 When using a texture on a pfTerrain I successfully map the texture
 coordinates with the following calls:

 // Init automatic texture generation
 ...

 // Set texture coordinate planes:
    pfTGenPlane(tgen, PF_S, -1,0,0,0);
    pfTGenPlane(tgen, PF_T, 0,-1,0,0);

 BUT, if I try that with my clipmap it doesnīt show up. If I instead use :

    pfTGenPlane(tgen, PF_S, 1,0,0,0);
    pfTGenPlane(tgen, PF_T, 0,1,0,0);

 The clipmap is shown, but upside down (with these calls the texture is
 also upside down). How can I show it correctly without doing any changes
 to my image-files?

Problem 2:
 If the origo of my pfTerrain isnīt (0.0) the clipmap doesnīt map
 correctly to it (only part of the clipmap is shown) - but a texture do!
 Why is that and what can I do about it?

I believe the two problems above can be solved by changing the Tgen calls
above, but I donīt know how...

Problem 3:
 Is there a 8-bit black-and-white performer image format that I can use to
 store the tiles of the clipmap on disk?

Thanks in advance!
  Jonas Andersson

________________________________________________________________________________
Jonas Andersson jonasa++at++cs.umu.se, http://www.cs.umu.se/~jonasa

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