Creating an emission map texture
Sometimes you have an asset available to you that you really like and want to use, but you want it to be emissive.
Except the artist didn’t create an emissive map texture file…
Just like those green scifi tanks pictured above.
That’s okay, we can make it ourselves.
Most people would do this in photoshop, but I don’t have it.
Most people without photoshop would do this in gimp, but I couldn’t make it work…lol
This person did it with Krita and it was so easy…
So, the first thing I want to do is select the relevant albedo map texture, use show in folder, and open the file in krita from there.
This makes it easy to save my new emission map to the exact same spot.
When I hit save as it will default to the same folder.
In Krita, the first thing I want to do is create 2 new layers.
One will be a black background for everything I don’t want to be emitting color, and one that will be white representing where I do want emission.
The albedo map I’m using has the glass stored as the alpha channel.
So I select the current albedo map, layer “Background”, use the magic select tool to highlight the alpha transparent area on “Background” layer, and then switch to my new layer that has nothing on it yet.
This is so I don’t draw on the background layer or my new black layer.
I then use the bucket fill to turn the transparent area to white.
Rinse and repeat for all alpha transparent areas on this image.
Then I disable visibility of the original image layer, turn on the black layer making sure that it is below my white layer, turn on the white layer, and do a save as.
Make sure not to overwrite the original file, you still need it for the albedo field in the Unity material!
I change the name to emission and its ready to go.
Back in the Unity editor, I make sure that the emission toggle is set to on, then drag my new emission map image into the corresponding field.
Because we chose to fill in our emission channel with white, we can use the Unity color select to change our emission to any color and shade we desire.
See you in the next article!