Introduction
ft-SSIBL for “Screen Space Image Base Lighting” is based on a topic I covered in a previous post about Roy Stelzer’s “2.5D Relighting inside of Nuke”. In this shader I tried to reproduced a few approach found in his Nuke script. So with a Normal pass (object or world), you will be able to do some relighting with a HDR map. The shader won’t compute the 9 coefficients (spherical harmonics) needed for you as describe in this paper : http://graphics.stanford.edu/papers/envmap.
The default value are from the Grace Cathedral, San Francisco Lightprobe http://www.debevec.org/Probes/
Download & Sources
- Pixel Bender shader : ft-SSIBL
- Source code : http://code.google.com/p/ft-projects/source/browse/trunk/PixelBender/ft-SSIBL.pbk
I will for sure add more feature to this one in the future, so come back check it out
How to install it ?
Just copy the .pbk file into your “Support Files” folder in your AE install directory
How to use it ?
How to convert a Light probe into the 9 spherical harmonics coefficients ?
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thaks men, you are a genious!!
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@Dan I just committed the code (didn't upload the file yet). on my GPU the difference is not so noticeable. But if I run the filter on CPU I got it 20% faster (in case the rotation are not equal to 0 of course, otherwise it's same as before).
Thanks a lot for the tips
oh this is true !
I was thinking about taking a look into those dependents function before, but never really did. I'll check that out.
I wasn't sure dependents function were called each time the user change a setting, I was afraid it was compute once at the shader init in AE. (but never tried it anyway).
I guess the performance will be the same as having no rotation since it is not supposed to evaluate those cos if rotations are set to 0.
I'm new with Pixel Bender, so I don't know all the little tricks about it. Thanks for the tips though
Nice work. Since the angle is invariant over the whole image, you should be able to make this kernel run much faster by only evaluating the sin & cos values once per render (instead of per-pixel) using Pixel Bender's evaluateDependents() feature
–Dan
So awesome, exactly what I was hoping someone would make
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