Thanks! I will try that.
On Jul 22, 2005, at 10:06 AM, Frank Condello wrote:
On 22-Jul-05, at 3:47 AM, Lo Saeteurn wrote:
Do anyone know how find how bright a point light is from a certain
distance (both linear and squared)?
Quesa (quite reasonably) uses a simplified GL light model, so the
attenuation factor in Quesa will always be:
LinearAttenuationFactor = 1.0 / Distance
QuadraticAttenuationFactor = 1.0 / Distance^2
The attenuation factor is applied to the RGB component (which is
used for both the diffuse and specular term, simplifying things
again). The RGB component is also scaled by a brightness value, but
you also have to take into account the luminance of the light's
colour. To get a normalized luminance value from an RB Color type,
you can use the following:
Luminance = (R/255)*0.30 + (G/255)*0.59 + (B/255)*0.11
So if my head's screwed on right the brightness at a given distance
from a light should be:
Brightness = (Luminance*(light.Brightness/100)) *
AttenuationFactor
You'll have to add the contribution for every light that reaches
that point, and you might also need to consider constant luminance
from directional lights, and the global ambient term.
Frank.
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