Only render shadows + generate character mask

Hello,

So I’ve been using Blender for game making recently and have hit two problems:

  • First, I wanted to create a “shadow-only” sprite, but obviously if I make the model invisible, the shadow does too.

  • Also, I want another sprite for masking, in order to allow the player to change the color of the character. However, just making the uncolored part of the character invisible doesn’t help since we can see the “interior” of the clothes, which I do not want.

I’ve been trying to search on internet on how to do these things, but found nothing.
I’m using Blender Render.
My sprite sheet is composed of 3 files: The character, its shadow, and the mask.

If you need further informations, feel free to ask.