I've been thinking about the essentially same problem as andff - that is, how to carry out calculations for texture surfaces that mix the R G B color components. The greyscale of an image would be computed as a mean value of the RGB channels,
C(result) = 0.333*C(R) + 0.333*C(G) + 0.333*C(B)
This formula involves multiplications of all the color channels which can be done with the MIX module. However, I haven't yet found a way to carry out the addition operation and I'm affraid that it's not possible with standard rendering operations. This is due to the fact that all rendering uses only one of the R, G and B channels at a time to calculate the value for the same channel. So what we need is a way to transform color channels to other channels and I don't know how to do it in R4.
Does anyone else have any ideas how to do it
