RE: [Algorithms] Bullets on walls

[Tom F. <to...@mu...>]

We know. Nothing on the planet supports something like ALPMOST_EQUAL as far
as I know (and even if it did, that still has problems when things walk
beside the walls).

You will have to either clip the decals to the wall geometrically; draw the
wall poly with clamp texture mode & the right UVs; or composite the decals
onto a wall-shaped poly, as suggested. If drawing individual decals, which
seems a popular method, then you will need some sort of Z-bias
functionality, which is what glPolygonOffset and moving the clip planes
gives you.

Tom Forsyth - Muckyfoot bloke.
Whizzing and pasting and pooting through the day.

> -----Original Message-----
> From: Angel Popov [mailto:ju...@bi...]
> Sent: 21 July 2000 15:50
> To: gda...@li...
> Subject: Re: [Algorithms] Bullets on walls
> 
> 
> No, neither glPolygonOffset or moving the near clipplane will 
> have the same
> functionality as the non-existent glDepthFunc( GL_ALMOST_EQUAL )
> because these two approaches will not fix the problem with 
> the wallmark
> not getting clipped at wall corners.
> 
> 
> > For D3D (and probably OpenGL), a good alternative is to 
> move the near &
> far
> > clip planes a bit further away for those tris. You only 
> need to move the
> > near clip plane if using Z-buffering. If using W-buffering, 
> you'll need to
> > move both.
> >
> > Tom Forsyth - Muckyfoot bloke.
> > Whizzing and pasting and pooting through the day.
> >
> > > -----Original Message-----
> > > From: Neal Tringham [mailto:ne...@ps...]
> > > Sent: 21 July 2000 10:56
> > > To: gda...@li...
> > > Subject: Re: [Algorithms] Bullets on walls
> > >
> > >
> > >
> > > Giovanni Bajo <ba...@pr...> writes:
> > > > In DirectX, there is a ZBIAS stuff that let you set a 
> priority order
> > > > (integer) when Z matches. It is a renderstate. But looking
> > > at the caps, it
> > > > is not supported in every boards I have tried. I heard 
> it is an old
> > > thingie
> > > > of first Voodoo boards.
> > >
> > > Yes, the support for zbias seems to be rather inconsistent.
> > >
> > > > I had not found something similiar in OpenGL.
> > >
> > > You may want to look at the 1.1 glPolygonOffset function.
> > >
> > >
> > > Neal Tringham (Sick Puppies)
> > >
> > > ne...@ps...
> > > ne...@em...
> 
> 
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