Opacity Shadow Map
Author
hi guys!
With regards to the eqn found in GPU GEMS 2,
Opacity(Z) = { Opacity(Zi)(Z - Zi) + Opacity(Zi+1)(Zi+1 - Z) } / (Zi+1 - Zi)
I understand that additive blending is done to accumulate with the previous opacity results, but how do you relate Opacity(Zi) and Opacity(Zi+1) in the eqn to the blending stages?
thx!
Edwin
Hey. Sorry if the chapter was unclear.
Opacity(Zi) is a sum over all the fragments in the hair which are closer than Zi.
So what we did was to render the whole hair, and use a shader to set each fragment's contribution to zero if it is farther than the specified z-value.
This gives us Opacity(Zi) - we can then compute Opacity(Z) using the formula you described, or using the code under the heading "Performing a Lookup".
Opacity(Zi) is a sum over all the fragments in the hair which are closer than Zi.
So what we did was to render the whole hair, and use a shader to set each fragment's contribution to zero if it is farther than the specified z-value.
This gives us Opacity(Zi) - we can then compute Opacity(Z) using the formula you described, or using the code under the heading "Performing a Lookup".
This topic is closed to new replies.
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