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hi everybody, i would like ton know how skydome can be implemented efficiently. Is there a good tut somewhere? thanks for the replies lunasol (in the sky with diamonds)

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They're not hard to implement, not hard to make efficient either. I'm planning on writing some new sky dome code for my apps, but the simplest method I've used is creating a gluSphere, clipping it along the X axis, and texturemapping it, and backface culling it. This isn't really efficient because gluSphere() creates a whole sphere, then I clip it, but backface culling helps slightly (actually, you should switch it to front face culling when drawing the sky dome as you will be on the inside). The complexity doesn't really have to be that great as it it so large (covers your whole world). Hope this helps.

Morgan

Note: draw the sky dome first and turn of depth tesing so it doesn't get clipped.

Edited by - Morgan on June 18, 2000 10:30:06 PM

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I''m writing sky dome code for my 4 elements contest entry(Hopefully I will make the deadline). There is a tutorial on flipcode, but I''m implementing my skydome completely differently. Hopefully I''ll have a public demo available before I submit it the program to the contest.

Domini

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http://everfall.cjb.net/
Sergey Stoma just released the source to his skydome app that won the last flipcode coding contest.

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Hi
using a textured gluSphere is very simple indeed! But i find it a little bit static... i''ve found the tut on flipcode but the explanations are short. Ok they give code with this tut but i''m a C programmer not C++
Hey Domi, what are the basic ideas of your skydome?

lunasol

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If you are trying to be efficient then experiment with different numbers of polygons in your ''Dome'' and try and find the lowest number that looks good, you may well find that a cube is fine. Don''t be afraid to prototype.

In my experience, the number of polygons doesn''t make too much difference (so keep it low), the most important part is the texture you apply to them. Make sure you have a good texture that tessellates well and you can''t see the joins and you should be laughing.


P.S. I don''t use OpenGL myself but surly it is simple to create your own basic shapes like a hemisphere with the triangles defined the same way around as the rest of your world so you don''t need to change front/backface culling part way through the rendering process.

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