Special Effects for BitBlt Games <- See the screenshot!

Basically this is a module with some functions I wrote to allow BitBlt games to use special effects. They're fast and look like the ones you see in real games, unless your computer is really slow. It has two function: AddBlt and SubtractBlt. They work like BitBlt but instead of copying, they add or subtract the images' RGB values... oh well, just look at the screenshot, you'll understand ;) This is version 1.1, the first one I forgot to comment the funstions so now you can understand how they work (comments on every line!).