Cubemap for dome

vvvv beta question
1

in mapping a dome, only half a cubemap is ever used
can one get away without having to render to lower half ?

2

You can render 4 sides only, with an edge facing upwards. If you search the forum for fisheye camera I think I posted something once

3

thanks for the link
do you mean the blue edge is facing upwards ?
so the 4 viewmatrices account for the roundness ?
why are there 2 types of meshes if the setup is symetrical ?
if there is no domemaster, could i map each slice via bezierpatch ?

Capture
Capture909×808 460 KB

4

Yes that’s the top of the dome.

To understand what’s happening here imagine rotating a box so one of it’s edges was facing / pointing upwards, and you used a camera with a fisheye lens to view the upper half of the inside of that box.

That box is equivalent to your cubemap. The meshes essentially encode the warping of that view of the sides of your cube faces, through a spherical (180degree fisheye) lens.

The technique, and everything else I ever learned about domes, is from this guy http://paulbourke.net

There is a lot of reading material on that site if you’re interested