Strategy to render shadows

BlitzMax Forums/BlitzMax Programming/Strategy to render shadows

Hi,

I have a problem rendering my shadows and got the feeling I'm doing it the wrong way. Here's how I do it now:

Background-"Layer" rendered first
B/W version ("created" with glBlendFunc GL_ZERO,GL_ONE_MINUS_SRC_ALPHA) of Sprites blended on top of this with a small offset (to emulate shadow)
Sprites drawn at last.

This method is very fast and looks nice (well, mostly). The problem occurs if two shadows overlap. The blendmode used cause the shadows to darken in this areas. Using "black"(alpha 1.0) as shadowcolor would help but doesn't look good.

Is this something I have to live with, or are there better solutions to draw shadows of alphablended sprites?
How do you do it in your games?

Jake

PS: I'm not limited to Max2D-commands, my engine use both Max2D and raw commands, but any solution should work under DX and OGL.