adding an alpha channel to an image

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3 comments, last by Possibility 22 years, 4 months ago
I am using DirectX and want to create some 32 bit textures that have an alpha channel. My school has photoshop 6 (but of course I have no manual for it) and tried some experimenting with it but couldnt figure it out. So how can I use photoshop(or paintshop pro) to add an 8bit grayscale bitmap to a 24bit RGB bitmap. And then in what format should I save this as (as a bitmap cant hold an alpha channel). Thanks in advance. Possibility
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why don´t you use two separate files? one grayscale for the alpha, and the rgb for the texture.. worked fine for me.

If you want to know more about this you should mail the guy at www.bunnz.com, he did the programming for the !Purple project (which used something like you want).
Yah, I know you can do seperate files, that is what I am doing right now, but I would like to combine them into a single which I believe you can do with a tar or tga or ppm file, I just need some help with the photoshop or paintshop pro to do it.

Possibility
In photoshop go to the channel window and create a new one. You will have option for what type of channel you want to create, select "alpha".

Make sure the alpha channel is active and not the R, G & B channels and paste the bitmap you want to use as the alpha channel in the "layer" of the channel.

Save as 32-bits TGA

Biere et punk
Hmm sorry you do not have option for what type of channel you create, but the one you create IS alpha...

Biere et punk

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