Re: [Algorithms] How to build sky?

[Corrinne Y. <cor...@ho...>]

-- You can render the sky as 6 in-sides of a cube.

-- 1. Render the sky cube faces with face culling facing inside / eye / you.

-- 2. Turn off zbuffer writes, so you don't ever clip your geometry against
your sky.
-- i.e., a sky is supposed to be infinitely far away.

-- 3. Offset the world position of the sky cube such that relative to the
eye-center, the sky cube always surround you the "same distance"
-- i.e., when you keep walking forward, the sun, moon, stars don't get
"closer" to you, they remain "just as far" because they are "supposed" to be
infinitely far.
-- Though in code/calculating reality, you don't need to set the size of the
cube to be infinitely far from the viewer, if you use the "move the skybox
as you walk" trick.

-- 4. Of course, only adjust absolute positional offsets. Don't copy
eye/self orientations and rotations, as in you are supposed to see the
"other" cube faces when you turn. So, viewer turns, but sky box orientation
remains fixed.

-- 5. Make sure the seams of your 6-bitmaps align.

-- Hope this helps.

Corrinne Yu


----- Original Message -----
From: "Pai-Hung Chen" <pa...@ac...>
To: <gda...@li...>
Sent: Thursday, September 28, 2000 2:05 PM
Subject: [Algorithms] How to build sky?


> Hi,
>
> What is the best way to build sky for an outdoor game?  I know a half-doom
> is typically used.  But is there any concern that favors the use of doom
as
> sky?
>
> Thank you,
>
> Paihung
>
>
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