Alpha textures

When creating alpha textures it is best to have a fairly powerful editing program, it mainly needs to have good cutting tools and preferably a magic wand. The program I use in this tutorial is 'Microsoft Digital Image 2006 Standard Edition Editor', I also use paint to help create my alphas(I use the more advanced program to cut the texture out and I create the alpha in paint. Whilst this tutorial is based upon this program if you have another program with similar cutting capabilities then it should be fairly easy to still use this tutorial.

First off grab an image/texture you wish to make an alpha. For this tutorial I will use a Stop sign as it is nice and simplistic. Open your image/texture in your editing program. First make sure that your texture is a power of 2 E.g. 128, 256, 512(I suggest 128 as it creates less lag), then using your cutting tools cut out your image, you can use edge finder and magic wand. If you are trying to do this in a program like paint, whilst it is not impossible it will take a very, very long time.

The texture has been resized to a power of 2, and then cutout so it can become an alpha(below).


I then save a copy and open in paint, I then fill the cutouts with black.


I then open this in my image editing program again, open your texture with the black filling.


Delete everything except the black sections. This will then create an external alpha. You will need to have a saved version of your image and your external alpha.


Now in the importer import your main texture and then select the alpha channel you wish to use.
Now select external alpha, a new window will apear asking you to select you external alpha.


Once your texture is an alpha, you will notice that below the texture it will say Alpha.


Now when adding the model and applying the textures, scroll across unitl you see placing, click the writing until it says 'Texture Only', this is what you want for alphas.


Now finish your importing as usual and you should have a working alpha channel.

Surfingoz
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