I saw there are some people struggling with Gimp and Alphas (for window textures) here and there, so I've written a short tutorial
You don't need other programs as Gimp and the DDS Plugin for it. Just see this as a addition and slight enhancement to Souls great tutorial
It took some time to figure out what's the best way to do but I found a satisfying way (at least for me
). This means there are maybe other ways
Make sure you have Gimp 2.8 and the DDS-Plugin installed (will not describe this here).
- Open your template (window template)
- Switch to channel view
- Duplicate the alpha to a new channel
- Click on the "eye icon" to not show this layer
- Click once on the red, blue and green channel (the blue highlight disapears, meaning you can paint on the alpha and the color-channels won't be changed)
- Select the hole image CTRL+A
- Press DEL (deleting the alpha)
- Fill the alpha with white color (full opacity)
- In channel list again click on the each color channel to enable editing of them again (the should get a blue highlight again!)
Now you should have a template ready to paint - at least if the template has a alpha layer Template you can edit. If not, you now:
- Click on the new duplicated alpha (in channel list, make it visible with the eye icon again)
- Select all CTRL+A
- Press CTRL+C to copy the alpha to the clipboard
- Click on the eye icon again to make it invisible
- Click on the base alpha channel (if the highlight disappears, click it again)
- Press CTRL+V to paste the duplicated alpha to a new layer
- Switch to the layer list
- Right Click on the new layer and click on "to new layer" (or equal)
- Rename the new layer to "Alpha" and put it to the very top
- Set the layer to invisible (click on the eye icon)
At this moment you do have a template to work with. You now can paint your name, sponsors etc. Just pay attention to have everything on a separate layer so you can take a selection from the alpha of the layer later when editing the alpha (described below). Put all new layers below the alpha (just for the organization of the template) and make use of the new layer groups, introduced by version 2.8!
If you have painted your name on the windows, perhaps added a sponsor, you now can make the alpha layer (not the channel!) visible again (click on the eye icon). Now you need to paint your names and sponsors to that alpha layer (or a new one above - better choice, as you can keep the original alpha). Use white for full opacity or black for no opacity or a grey for half opacity etc.
You can get a selection from other layers (e.g. your name layer) by rightclicking on it and click on "selection from alpha". Now click on your alpha layer (or the new one) again and fill the selection with your desired greyscale color.
Now you are ready to export your image. For that you do as follows:
- Save your template to a new file in Gimp's native layer format (*.XCF) so you can easily go back there at a later point
- Make sure all alpha associated layers are on top of all layers and have the correct order (no other layers, non alpha associated layers should shine through)
- Rightclick on a layer of your choice and click on "new from visible"
- Put the newly created layer to the very top (if not already)
- Press CTRL+A and CTRL+C to copy the layer to the clipboard
- Switch to the channel list
- Click on your duplicated alpha (make it visible by clicking on the eye icon before, make sure the channel is highlighted)
- Press CTRL+V to paste the layer from the clipboard
- Choose the selection tool and click on the outside of your image (grey backgound). The cursor should have an anchor symbol at it's side before you click, so with a click you anchor the pasted layer to the duplicated alpha channel.
- Click on the eye-icon again to make the channel invisible again. Don't get irritated if the image hase strange colors before you make the channel invisible - this is a normal behaviour.
- Switch to the layer list
- Make all alpha associated layers invisible
- Flatten the image (Menu: Image -> Flatten Image)
- Right click on the remaining layer and click on "add layer mask"
- Choose the option "channel" and make sure your duplicated alpha is selected from the list (if you only have one, this will be choosed and you don't need to take care of this)
- Click "add"
- Rightclick on the layer again and click "apply layer mask"
Now your window skin is ready getting exported. To do so choose "File -> Export..." in the menus. Navigate to your desired location, set a name and add the fileextension ".dds" to it. After clicking on export the settings dialogue the DDS Plugin appears.
Setup as in the following picture.
Now you can check your texture ingame. Everything should like fine but if there are mistakes, just undo all steps until you have your layers again (or reload a saved file) and correct the mistakes. After that you can simply (in short) update your duplicated alpha, flatten your image, apply the layer mask and export your image again.
Some sticking points:
- if your window-texture looks strange try other DDS export settings for the mipmaps and color selection
- if your window-texture has a strange color, just go back to the step before you apply the layer mask to your image and reset your colors (in the toolbox click on the black/white icon next to the color chooser) and after that apply the layer mask
Anything missing? Just drop a line and I will add it
