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Standing in Foxholes?


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3 minutes ago, Redwolf said:

I wonder whether the underspecified nature of the BMP file format is responsible. Can you point me to such a file? I want to see what ffmpeg has to say about it.

in example CMRT v100a.brz Then terrain/foliage/tree. The "leaves" files contain a b/w mask alpha channel. There´s CM files containing grayscale alpha channels as well.  ATM can´t remember some examples.

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4 minutes ago, Redwolf said:

Net find:

https://gitlab.gnome.org/GNOME/gimp/-/issues/461

"[...] First, among all three bmp files attached here, only 240849 is a "real" 32bpp-RGBA file. It's a BITMAPV5HEADER BMP file.

The two others files are ambiguous since BMP specification (BITMAPINFOHEADER) is not clear about the alpha channel in 32bpp files. There is no way to know if 4th channel bits must be read or ignored. Thus it's best to ignore the extra bytes and this is what GIMP 2.8 does"

So you would be fine editing in GIMP if you were to find a program that converts random BMPs to BITMAPV5HEADER BMPs and then load in GIMP. I bet ffmpeg can do that, the question is whether it in turn reads the alpha channel data on the input side.

yep, might be. But it´s exactly those extra steps I´d like to avoid. Until Gimp adds that function natively (or 3rd party plugin), CS2 does it perfectly fine for me. Also it´s always good to know which type alpha channels is contained in original CM files. As said there´s 2 at least (b/w and grayscale).

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