ufoRasterSetPixelCol sets the RGB values in a pixel.
Values should be normalized in the range (0..1).
Depending on the raster type, the values set are as follows:
• Called on an RGB raster sets R=r, G=g, B=b
• Called on an A raster sets A = (r+g+b)/3
• Called on an RGBA raster sets R=r, G=g, B=b, A=1
Autodesk Softimage v7.5