Re: [Visualpython-users] Color / Intensity Question

[Bruce S. <ba...@an...>]

--On Sunday, October 21, 2001 21:29 +0000 Do...@ao... wrote:

> Background on the first question.  I am looking into doing some
> experiments with VPython using digital video output which could have some
> applicability to driving a scene projector. I am trying to understand
> what data is being generated, how many bits etc., so I can decide how to
> encode and grab off from digital video the scene intensity data.

Surely this has much more to do with the color depth of your video card 
than with Visual.

> On another related question. How does VPython handle rendering object
> data which is sub-pixel?  If I for example have a scene.range of say 1000
> meters, and say 200x200 scene.x and scene.y, then a screen pixel is on
> the order of 5 meters. (Math kept simple, in deference to me).  If I have
> an object that is, say a 1 meter sphere, will it not appear, or only
> appear is it happens to be hit by some sampling process?

Try it! You'll see that very small (or equivalently, very distant) objects 
don't display. There might be some question as to whether they should 
display one hardward pixel, but currently they don't. (I'm assuming you 
mean "scene.width" and "scene.height", not "scene.x" and "scene.y".)

> Oh, before I forget.  I have a simple program that looks at a
> number of objects that are rotating.  When I use scene.range
> to specify the effective field of view, it behaves nicely.  If I use
> scene.fov, there is a weird motion of the scene.  I will include a copy
> for  your amusement, probably at my stupidity...

I don't understand the issue. When I run your program using either range or 
fov, the behavior looks the same to me. Say more? What platform?

Bruce Sherwood