Re: camera angle affects lighting

[Frank C <li...@si...>]

On 26-Jul-04, at 4:06 PM, Keith Wiley wrote:

> On Mon, 26 Jul 2004, Dair Grant wrote:
>
>> Keith Wiley wrote:
>>
>>> Has anyone ever noticed that the camera angle can affect the apparent
>>> illuimation of surfaces?  As I rotate the camera, the brightness of a
>>> surface changes even though that surface's location in global space,
>>> and with respect to the environmental lights never changes.
>>
>> Not sure if I follow - if you change the camera view, you'll be 
>> looking
>> at a different part of the object, and hence you'd expect the
>> illumination to change surely?
>
> No, look at this example to see what I mean:
>
> http://www.cs.unm.edu/~kwiley/illuminationError.jpg

That is almost certainly a specular highlight you're seeing. If you're 
not using Phong shading, then it's a bug. If you are using Phong 
shading, it's expected behaviour (highlights clip to polygons not 
alphas).

Frank.