Sprite shadows

Sprite shadows
A separate sprite is used to define fake shadows. It is created from the source 3d model of the sprite, but as a separate image. The image is binary, where it is black there is no shadow, where it is some other colour, there is shadow. This shadow is rendered as grey transparent "something" in-game. See screenshot for examples of this method: http://www.cheats.ru/uploaded/d/diablo2-01145.jpg

The tree and the characters are casting shadows. Other objects and terrain, do not get occluded by this shadow but only affected.

Another example: http://www.gamershell.com/static/screenshots/2727/42570_full.jpg. The tower in the middle of the screen is casting a shadow. Two men are in the shadow. Terrain sprites are affected, while the unit sprites are not. FIFE should perhaps follow the same principle. There is a need to define the drawing order of the shadows, due to the way the affect certain thnigs and don't affect some other.

A sprite object would then look like this: http://img149.imageshack.us/img149/9181/objectus5.png

While its "shadow" sprite would look like this: http://img266.imageshack.us/img266/8832/shadowpf6.png

If the object's shadow is a part of the sprite, the end result will look weird, due to the special drawing position the shadows have in the rendering hierarchy. At least two major games (red alert 2 and AoE2 went with this approach)