yeah, I'd think so, but it seems pretty straightforward to me. You know Pixel Bender pretty well, so I'm figuring that I'm misunderstanding your question.
try the steps I described above.
Once by filling the layer with Black and the other by filling with White.
There's something tricky about it, it's not a classic "Luminosity Mask".
Clicking on the RGB channel creates a selection by the Luminosity, that's easy to do with Pixel Bender.
The "Filling" part, that's what I'm missing.
For example if you take a pure black pixel, its Luminosity Mask is 0.
Yet If you fill it you'll get something completely different.
Not sure if I understand your question right but I think this is what you want !?!
<languageVersion : 1.0;>
< namespace : "Felix Dames";
vendor : "Felix Dames";
version : 1;
input image4 src;
output pixel4 dst;
float4 pixel = sampleNearest(src,outCoord());
float luminosity = (pixel.r + pixel.g + pixel.b) / 3.0;
dst = float4(1.0,1.0,1.0, luminosity); // here you can change the fill color
hope it helps
Worked like a charm, Thank you.
I thought about it and for some reason never gave it a try.