After some fiddling, I found this way to pull the alpha channel out of alpha and into the main channel(s), for further processing (e.g. [pix_gain] and [pix_levels]).

I wonder if there's a better way but this seems OK. Posting in case it helps someone later.

hjh

Hm, actually, no, that seems not to do exactly what I thought. It seems that what I've got is a pix where R = 1, G = 1, B = 1 and alpha is as it was.

What I want is a pix where R, G and B all = the alpha channel.

Is this even possible in Gem?

hjh

@ddw_music i think it will be possible. I don't know how hacki it will be. Maybe not at all using [pix_colormatrix] ?

...also it should be possible with shaders. And if nothing helps than with [pix_data] banging and setting via color (the hack-hack-hacki solution).

@Johnny-Mauser said:

@ddw_music i think it will be possible. I don't know how hacki it will be. Maybe not at all using [pix_colormatrix] ?

[pix_colormatrix] does appear to be the droid I was looking for: A matrix "0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1" does the job: R = m[0] * r + m[4] * g + m[8] * b + m[12] * a, G = m[1] * r + ... etc. so with this matrix, at the end, R = a * 1, G = a * 1, B = a * 1.

Thanks for the tip!

hjh