Cube Map Coordinates

[mshukun]

Might anyone know what coordinate system is applied in the cube map? The code below was kindly provided to me using this forum, but I need to know the actual coordinate system used in the cube map in order to perform further downstream processes. For instance, if a spherical coordinate system is used in the cube map, how can I find radius of the sphere? On the other hand, if a cube coordinate system is used, how can I ascertain the height, width and depth of the cube map? (Thanks in advance for any assistance you can provide in this regard, which is greatly appreciated.)

import viz
import vizmat
import vizshape

viz.go()

env = viz.addEnvironmentMap('Farm2A.jpg')
sky = viz.addCustomNode('skydome.dlc')
sky.texture(env)

viz.link( viz.Mouse , viz.addTexQuad(viz.SCREEN,texture=viz.add('crosshair.png')) )
viz.mouse.setVisible(viz.OFF)

def placeMarker():
line = viz.MainWindow.screenToWorld(viz.mouse.getPosition())
pos = vizmat.MoveAlongVector(line.begin,line.dir,40)
shape = vizshape.addCircle()
shape.color(viz.GREEN)
shape.billboard()
shape.setPosition(pos)
print shape.getPosition()
#place a marker when the left mouse is pressed
vizact.onmousedown(viz.MOUSEBUTTON_RIGHT,placeMarker)

import vizcam
vizcam.PanoramaNavigate()

Image: Spherical coordinate vs Cube coordinate
http://screencast.com/t/hSkab1MNKk