Isotropic phase function

[GoogleCodeExporter]

Hi, 
I hope I am not wrong but it seems to me that the solid angle of the sphere 
should be 4_PI.


Please let me know If I overlooked something elsewhere or if this is indeed a 
bug;


Shader:: CIsotropicPhase:: HOD CColorXyz F(const Vec3f& Wo, const Vec3f& Wi)
    {       
        return m_Kd * INV_PI_F; 
    }



Regards, Christoph

Original issue reported on code.google.com by [email protected] on 19 Jun 2012 at 1:28

[GoogleCodeExporter]

This is in fact correct.

You could check the lambertian shader in PBRT, which is quite similar to an 
isotropic phase function, except that in stead of 2 * PI, the phase function 
envelopes 4 * PI.

Cheers,

Thomas

Original comment by [email protected] on 24 Jun 2012 at 10:58

[GoogleCodeExporter]

Ah, thank you very much for your reply.

Unfortunately I currently have no access to pbrt, but I would be glad if you 
could spend a sentence or two to help me understand this.

I am a little confused that the "Isotropicphase.F" is anything but 
isotropic. And furthermore there is allready a "lambertian.F".

And in case of a lambertian.F, shouldn't be the pdf be halfed e.g. use the 
cos term as well?

Sorry for this messy question, I would be glad if you would reply.

Thank you,

Christoph

Original comment by [email protected] on 24 Jun 2012 at 6:47