Complete from-scratch rewrite of my original CPU mask maker, but now on the GPU and with more features, and a better UI Allows you to quickly create a mask from a pre-existing texture
Open the program from under the Window tab, called "Mask Creator"
Load your texture into the "Input Image" entry on the left of the new window
Select the upper bound color by clicking on the black square under the "Max Color" label, then click on the input texture to eyedropper that color
Repeat for the "Min Color" and "Background Color"
Click on the input texture to generate the initial mask
Once you are done, click on the "Output Mask" button to write the mask to a file; the final file will be next to the source texture's file