Sky Brushes

Anyone any ideas as to how to implement Quake-Like Sky Brushes?

I've come close by mapping vert UV's to a spherical Sky Texture at runtime depending on the pitch and yaw of the camera. However, because the texture is mapped perspectively correct I get undesireable distortions. I'm pretty sure there is no linear mapping option in Blitz3D so I'm looking for a better solution.

I could use CubeMapping but I'de rather have a solution that was compatible with all/most video cards.

Using a Sky Box or Sphere is not an option due to the nature of the map structure (it's Doom/Marathon like).

Make a plane, texture it, then scroll the texture using PositionTexture.

Create a background sphere, this will be the atmosphere and lighting for the sky (set it to render order 4, then create a clouds layer- this can be a plane, it just has to overlay the atmosphere and fade out in the distance (or make it a sphere/sky cube, whatever suits you) and set it to render order 3, then create the horizon (mountains/trees/buildings/etc) and set it to render order 2. Only things you need to update are the atmosphere/lighting and cloud layers. Former would probably be rotation along some axis, latter would usually just be the texture shifting and its alpha changing depending on 'time of day'.

Sorry, bit of a messy response.

Sorry, i don't think i made myself too clear.

I'm looking for a means to map a sky texture to a solid poly on the map geometry itself. This is where the quake comparison came from. When constructing a quake map rather than having an open ceiling or window exposing a sky box or the like you map the geometry with a "special" sky brush. By special I mean it isn't mapped like usual textures, it's mapped in such a way that it exposes a background/sky scene.

Wrongo: if they render before everything else, they'll look fine.

Yes I know how sky boxes work. I am not asking how to do a sky box though, I'm asking how can I map a backround scene onto an area of my level mesh to achieve a cube-mapping like effect but without the hardware dependancy.