RE: [Algorithms] Skysphere or skybox?

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Unreal used the same trick.

-----Original Message-----
From: Tom Spilman [mailto:tsp...@mo...]=20
Sent: Wednesday, April 24, 2002 7:04 PM
To: gda...@li...
Subject: Re: [Algorithms] Skysphere or skybox?

RE: [Algorithms] Skysphere or skybox?> On Heavy Metal: FAKK2, we
actually let them draw the sky as
> just a point in the world, so they could even have scripting and stuff

> , or rotate the entire background by moving the camera.  Really cool=20
> stuff.

    Yea that was great.  If you put FAKK2 into noclip mode and fly
outside the scene you'll normally find another little scene for the sky
box.  I remember finding that in the final boss level where all these
giant asteroids were flying thru the sky... really cool.  Tom

----- Original Message -----
From: Jack Mathews
To: gda...@li...
Sent: Wednesday, April 24, 2002 5:23 PM
Subject: RE: [Algorithms] Skysphere or skybox?

On Metroid, we just let the artists specify a skybox model, always
render from the center of it, then clear Z and draw the rest of the
scene.  Works like a charm, and they get really good stuff.  The
advantage is that they get everything from the model system too, like
animated UV's and the like. On Heavy Metal: FAKK2, we actually let them
draw the sky as just a point in the world, so they could even have
scripting and stuff, or rotate the entire background by moving the
camera.  Really cool stuff. Jack -----Original Message-----
From: George Warner [mailto:ge...@ap...]
Sent: Wednesday, April 24, 2002 3:55 PM
To: Joris Mans; gda...@li...
Subject: Re: [Algorithms] Skysphere or skybox?
on 4/24/02 1:03 PM, Joris Mans at <jor...@pa...> wrote:
> And what about when the player looks straight up? Isnt the distortion=20
> visible?
The skybox (or skycube) has a top and bottom with (pre-distorted)
textures mapped on them so they look ok. For the sky-cylinder the ground
hides the bottom of the cylinder and I add a "sky" (plane with texture)
to cutoff the top of the cylinder so you won't see the distortion up
there.
BTW: You could also consider the yon-plane: Map a texture onto a plane
that's just this side of yon. It's relationship to the camera is always
fixed; You'll have to "move" (or pan) the texture on this plane to
simulate rotation.

> On another note, how does one generate mapping coordinates and/or=20
> construct the texture?
The parallax distortion is the inverse of the cos of the angle between
the plane of the box and the line of sight (thru the camera). In other
words, strait ahead (where the view angle is 90 degrees to the box
plane) the distortion is zero. At the edge of the box (45 degrees from
strait ahead) the distortion is at the maximum (1/2?). (to go beyond 45
degrees you would be on the next side of the box and be decreasing from
45 degrees.)
--
Enjoy,
George Warner,
Mixed Mode Magic Fragment Scientist
Apple Developer Technical Support (DTS)

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