Would you like a conversion example from Pixel Bender to GLSL or a guide to writing similar filters in modern Photoshop with JavaScript?
input image4 src; output pixel4 dst;
void evaluatePixel()
<languageVersion : 1.0;> kernel GrayscaleFilter < namespace : "MyFilters"; vendor : "YourName"; version : 1; description : "Converts image to grayscale"; > pixel bender toolkit