scott wrote:
> 1. Set render target to temporary one
> 2. Render scene without ghost normally, but set stencil writes to always 0
> 3. Render ghost geometry without writes to RGBA, but stencil write of 
> always 1
> 4. Switch the render target to the actual back buffer
> 5. Render a full-screen quad to simply copy over the entire temp buffer 
> RGBA contents
> 5. Set your special effect pixel shader
> 6. Set stencil pass function to equal 1
> 7. Render a full-screen quad at the depth of the ghost (this will avoid 
> affecting anything infront of the ghost)
> 8. Render the ghost normally

I was following you up until 7. First, since the ghost is a model, I'm not 
sure what the single "depth" would be. But OK, assuming I'm not actually 
intersecting geometries with the ghost, I can work with that.  However, 
doesn't step 5 destroy the original depth information? That was the step I 
couldn't figure out how to get around. If I've turned the 3D models and such 
into a flat quad, I've lost the original depth information there.

Secondly, I'm not sure what 7 is for at all. Maybe you're thinking something 
different for "render ghost" than I am? Does step 8 mean "render the parts 
of the ghost you can't see through" or something?  Do you mean that 7 will 
combine the stencil buffer with the depth buffer somehow? Wouldn't the 
stencil buffer already be 0 where there's something occluding the ghost?

> Sure, if you write depth on purpose to a special render target, what is 
> not normally available is the "internal" depth/stencil buffer that the 
> GPU uses to do depth and stencil tests during normal rendering.  So 
> you're usually having to duplicate the depth buffer if you want to use 
> it in a non-standard way.

True. I think keeping two copies of the depth buffer is less overhead than 
rendering all the geometry twice, tho.  That's really the bit I'm trying to 
avoid.

-- 
Darren New, San Diego CA, USA (PST)
   Serving Suggestion:
     "Don't serve this any more. It's awful."

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