Shadows

check opengl.org + the nvidia theres heaps of ways unfortunally none are easy

Here''s a method that uses the stencil-buffer:

Shadow Volumes

I''m not sure if anyone''s still interested, but,
anyway, just a thought (for D3D):
1. suppose you color-code each triangle (or each object - depends on your needs) with a distinctive color;
2. then you render all ''to the light'' (i.e. you put your camera at your light source) flat-shaded with these color-code values;
3. then you render all flat and color-coded to ''normal'' view using this light-view image (from the previous pass) as a projective texture (you will have to calc tex.coords accordingly (or use appropriate DX7 features) with D3DTOP_SUBTRACT operation. Thus, all parts ''visible'' to the light source get zero color, and all invisible ones get some non-zero value. In other words, all non-zero pixels will belong to the image of your shadow.
4. Then, there''s a number of ways how to bring this multi-colored shadow image to a single color (dark gray, preferrably). This maybe either color-keying of a color-space (which is not supported by Nvidia chips, unfortunately) or you may do some
tricks blitting the whole thing directly to Z-buffer, in which case the blue components get directly to its (z-buffer''s) stencil part (this is weird, I know, but it works on my GeForce2)

Sorry for giving just a raw idea, haven''t had no time recently to code it up :-(