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THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED
On 08/01/2004 at 18:53, xxxxxxxx wrote:
User Information: Cinema 4D Version: 6.303 Platform: Windows ; Language(s) : C.O.F.F.E.E ;
--------- I am learning about anti-aliasing in COFFEE via the Texturing and Modelling book and sample RenderMan shader. I often see a reference to the following: /* Estimate the filter width -- i.e. the change from pixel to pixel -- of * float and point values. */ #define filterwidth(x) (abs(Du(x)*du) + abs(Dv(x)*dv))
How can we obtain the filterwidth for the pixel currently being shaded from the VolumeData object? Cheers
On 09/01/2004 at 13:35, xxxxxxxx wrote:
Hard to tell without knowing what 'Du(x)' and 'du' are in the code. I don't know anything about RenderMan. Does anyone else know?
On 09/01/2004 at 15:16, xxxxxxxx wrote:
du [scalar] - Change in u across element du [scalar] - Change in v across element dPdu [vector] - Change in position with u dPdv [vector] - Change in position with v Du(expr) - Compute the parametric derivative of the expression "expr" with respect to the u parameters of the underlying surface Dv(expr) - Compute the parametric derivative of the expression "expr" with respect to the v parameters of the underlying surface
On 10/01/2004 at 00:40, xxxxxxxx wrote:
I'm not sure what to map that to in the C4D SDK. Perhaps VolumeData::delta could do, if all you want is to avoid aliasing?