Tim Sweeney on Shadow Maps, stencils and unified lighting!

[AlNom]

What about buildings? Those are bigger than 3m cubed.

 

[DudeMiester]

lol, I said 3m^3 and larger

 

[T2k]

Well, what about John Carmack's solution...shadow maps globally? Won't that solve the problem quite nicely?

Lsat time I've chcecked they released a game (techdemo ) with heavy stencil use...

And when I pointed out back then as it is now (then), that's a dead end, everybody called me on all kinda names....

Suprisingly now even XXXStrato opens a topic about the death of stencils...
How times change... 8)

 

[Richard]

And when I pointed out back then as it is now (then), that's a dead end, everybody called me on all kinda names....

I think the problem with that discussion is that while stencils don't follow recent GPU scaling trends, it was the right decision to go for stencils instead of shadow buffers for D3's timeframe. JC already said that the sb implementation of D3 is "quite a bit slower" than the stencils one. So while it is a dead end, it isn't (or rather, wasn't since D3 has been released already) dead yet.

 

[Laa-Yosh]

Please allow me to remind you that UE3 relies on stencils as well, to generate shadows from dynamic lights affecting moving objects... stencils will stay for another few years, like it or not

 

[Dave B(TotalVR)]

How about overlaying a precedural 3D texture onto the stencil shadow volume, then at the face of every polygon inside blend the procedural texture (which will be of intensity) with the surafce texture?

How would you generate the procedural 3D texture, though? I mean, it'd work great, I just don't know how you'd do it.

well, when you generate the volume you generate a second, larger volume as if the light source were further forward. Then you can subtract one volume from the other and end up with a hollow cone. Then you could just apply a simple procedural texture that interpolates between the intensity at the inside (0) and the outside (1) edges of the volume. i.e. the inside edge closest to the center of the shadow volume and the nearest outer edge traced along.

Would require some extra logic I expect but I have a funny feeling that logic is already present on a PowerVR based card in its HSR unit. Dammit PVR! gimme a job, I got ideas!

 

[XxStratoMasterXx]

Well, what about John Carmack's solution...shadow maps globally? Won't that solve the problem quite nicely?

Lsat time I've chcecked they released a game (techdemo ) with heavy stencil use...

And when I pointed out back then as it is now (then), that's a dead end, everybody called me on all kinda names....

Suprisingly now even XXXStrato opens a topic about the death of stencils...
How times change... 8)

T2K,

I've never been a proponent of stencils over shadow maps. Now, for a robust, unified shadowing pipeline for Doom 3's timeframe, and for a while if the dev wants to go unified, stencils are great. Using sampled shadow maps completely dynamically unified would probably not be viable for a while.

Yes, and Unreal Engine 3 is mostly stencils, don't be fooled. All dynamic lighting on environments casts stencils, and only characters get dynamic soft, shadow mapped, shadows. Funny how Tim Sweeney bashes stencils, but then puts stencils as the primary shadowing engine in his renderer (well Andrew Schiedeckers renderer )

I really wish I could get my hands on Carmack's experimental shadow-buffer code and toggle between shadowbuffers and volumes.

 

[Reverend]

Funny how Tim Sweeney bashes stencils, but then puts stencils as the primary shadowing engine in his renderer

Is that what Tim said?

 

[XxStratoMasterXx]

Funny how Tim Sweeney bashes stencils, but then puts stencils as the primary shadowing engine in his renderer

Is that what Tim said?

Well according to the Unreal Engine website (www.unrealtechnology.com) dynamic lighting that casts shadows on anything but characters are stencils.

 

[squarewithin]

Funny how Tim Sweeney bashes stencils, but then puts stencils as the primary shadowing engine in his renderer

Is that what Tim said?

Well according to the Unreal Engine website (www.unrealtechnology.com) dynamic lighting that casts shadows on anything but characters are stencils.

Though the E3 engine video shows that lamp with the distance-based soft shadow via interpolating between 2 cubemaps.

 

[XxStratoMasterXx]

Funny how Tim Sweeney bashes stencils, but then puts stencils as the primary shadowing engine in his renderer

Is that what Tim said?

Well according to the Unreal Engine website (www.unrealtechnology.com) dynamic lighting that casts shadows on anything but characters are stencils.

Though the E3 engine video shows that lamp with the distance-based soft shadow via interpolating between 2 cubemaps.

Yeah, but that's for that particular situation.