"Your pony died because it wasn't pretty enogh..."
х_Х
This tutorial describes how to convert semi-transparent polygon shadows into scenery with Gimp. It should take less then 5 min.
Technique to use semi-transparent polygons to create fading/shadow effects can give quite an impressive results. However it isn't very popular since using polygons with semi-transparency in not a FPS-friendly solution. So converting them into scenery can solve this problem.
Demo map
attached.
1. So I've got some polygon shadows on my map and now going to convert them into sceneries. Ensure that shadow polygons are colored with 100% black and there is no gaps between them.
2. Go to PW preferences and set background colour to pure white. Click OK.
3. Select all shadow polygons. This can be done by selecting black colour as current and using "Select by colour" item in the Edit menu.
4. Drag them to some empty space and deselect. Make sure that zoom is set to 100% (press *) and only polygons and texture are visible. Make a screenshot.
5. Start Gimp, paste screenshot into new image (Main menu=>Edit=>Paste as=>New image). Select shadow area with Rectangular selection tool.
6. Make selection floating (Main menu=>Select=>Float). Create a new layer (Main menu=> Layer=>New layer) so your floating selection will become a new layer. Delete bottom layer with the rest of screenshot image.
7. Duplicate the shadow layer (Main menu=>Layer=>Duplicate layer). Invert it's colours (Main menu=>Colors=>Invert).
8. Add a "Transfer alpha-channel" ( ! not "Layers alpha channel" ! ) mask to the bottom ( ! not inverted ! ) layer (Main menu=>Layer=>Mask=>Add layer mask).
9. Here comes the tricky part: Cut the inverted layer and paste in over the mask ( ! not over the bottom layer itself ! ). In order to ensure this click on the mask on the Layers panel. Result should look like this:
10. The result of the previous action doesn't look any near the expected, but do not worry! Apply layer mask (Main menu=>Layer=>Mask=>Apply layer mask). Colorize the image (Main menu=>Colors=>Colorize) as shown on the screenshot. Woa! Now it looks much better. I suggest to colorize it into pure white since this will help to reduce the file size and actual colour can be later adjusted in the PW.
11. The scenery is almost ready, all left to do is to save it as png file. But first remove the colour information (Main menu=>Image=>Mode=>Grayscale). Save file as png with the shown setting.
Result: 576x301 px 16 bpp 11 kb png image
12. Lets try new scenery in the PW. It looks exactly as the polygons shadow!
You can also try applying some additional filters (such as blur or softglow) to shadow to make it look softer and more natural.
