[Visualpython-users] Setting camera position

[Bruce S. <Bru...@nc...>]

Placing the camera in a particular position is not as simple as it 
probably ought to be. I think the reason that scene.mouse.camera is 
read-only has to do with synchronizations issues, but I'll admit to 
being a bit hazy on this issue.

Here is a way to place the camera at a specific location, in this case 
(10,10,10):

from visual import *
box()
d = vector(10,10,10)
scene.forward = -norm(d)
#scene.fov = pi/3 (the default fov)
scene.range = mag(d)*tan(scene.fov/2)
print scene.mouse.camera # not updated yet
print scene.forward
scene.mouse.getclick()
print scene.mouse.camera # now shows <10,10,10>

The key geometrical point is that scene.fov is the angle subtended by 
the scene, so the tangent of half of that angle is the range (recall 
that range=1 means the scene goes from -1 to +1).

Bruce Sherwood