Comments on: A (not so) little teaser http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/ Mon, 12 Oct 2009 22:17:15 +0000 http://wordpress.com/ hourly 1 By: Time for a brief update « Pixels, Too Many.. http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-104 Time for a brief update « Pixels, Too Many.. Wed, 23 Jan 2008 09:32:50 +0000 http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-104 [...] January 23, 2008 — Marco Salvi Four months ago I tried to stimulate your curiosity with this post. Next month I will try to stimulate it even more with this talk at the upcoming Game Developer [...] [...] January 23, 2008 — Marco Salvi Four months ago I tried to stimulate your curiosity with this post. Next month I will try to stimulate it even more with this talk at the upcoming Game Developer [...]

]]> By: multisample http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-103 multisample Tue, 15 Jan 2008 17:13:33 +0000 http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-103 So ... anymore info than this little teaser. Its definitely got me intrigued, but you have kept the important info to your self :) Any idea when we will find out more ? So … anymore info than this little teaser. Its definitely got me intrigued, but you have kept the important info to your self :) Any idea when we will find out more ?

]]> By: Marco Salvi http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-43 Marco Salvi Sun, 16 Sep 2007 05:49:49 +0000 http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-43 to purpledog: I'm very interested in your idea, cause I don't like warping schemes for shadow map projections (I believe they are all a big waste of time..). What you're exploring is the way to go imho, ideally we want to make sure the number of pixels needed to sample visibility from a punctiform light converges to the number of pixels we employ to sample the scene from the camera. While you're working on your idea don't forget to factor in shadow maps filtering algorithms that work in light space -> give away just a bit of shadow map resolution and leave some space on the image boundaries so that visibility reconstruction filters have full support ;) Congratulations for also working with one of the most brilliant young researchers around these days, the stuff he did with Hoppe is pretty amazing. Interesting your last comment: the irregular z-buffer paper shows how to turn rasterization into ray-casting/first hit ray tracing but it requires hw support, construction/maintenance of a spatial subdivision structure and it kills every opportunity to have cheap smooth/soft shadows, which means we won't see it running in realtime anytime soon. So we definitely need something in the middle that leverage on common/fast/cheap rasterizers! to SMM: What my friend Jim is trying to say is that I don't drink. Don't worry..you can have your beer, I'll have an orange juice..:) to purpledog: I’m very interested in your idea, cause I don’t like warping schemes for shadow map projections (I believe they are all a big waste of time..). What you’re exploring is the way to go imho, ideally we want to make sure the number of pixels needed to sample visibility from a punctiform light converges to the number of pixels we employ to sample the scene from the camera. While you’re working on your idea don’t forget to factor in shadow maps filtering algorithms that work in light space -> give away just a bit of shadow map resolution and leave some space on the image boundaries so that visibility reconstruction filters have full support ;)
Congratulations for also working with one of the most brilliant young researchers around these days, the stuff he did with Hoppe is pretty amazing.
Interesting your last comment: the irregular z-buffer paper shows how to turn rasterization into ray-casting/first hit ray tracing but it requires hw support, construction/maintenance of a spatial subdivision structure and it kills every opportunity to have cheap smooth/soft shadows, which means we won’t see it running in realtime anytime soon. So we definitely need something in the middle that leverage on common/fast/cheap rasterizers!

to SMM: What my friend Jim is trying to say is that I don’t drink. Don’t worry..you can have your beer, I’ll have an orange juice..:)

]]> By: ShootMyMonkey http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-38 ShootMyMonkey Thu, 13 Sep 2007 06:41:52 +0000 http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-38 Jim, I'll do what I can... :) when you say "hard," do you mean hard to push him (i.e. he has too much self-control) or hard to get him anywhere towards that point (i.e. he can hold his liquor)? You're welcome to join in -- we can double-team him ;). Jim,

I’ll do what I can… :) when you say “hard,” do you mean hard to push him (i.e. he has too much self-control) or hard to get him anywhere towards that point (i.e. he can hold his liquor)? You’re welcome to join in — we can double-team him ;) .

]]> By: purpledog http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-37 purpledog Wed, 12 Sep 2007 17:30:11 +0000 http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-37 Well, my take on the subject is exactly like yours, yoda: "it would be just better to partition the screen in a few regions and apply regular projections on each area" :-))))) The general idea is to code an efficient "deformable" grid" which keep some good property: - converge very fast to "area of interest" (a bit like amagnigying glass really) - allow holes (or maybe not) - stable over time (or maybe not...) The "area of interest" are the stuff like the eye can see bits view from the light. One big problem comes from the fact that once the grid is done then one has to render the polygon which can span over many cells. The geometry shader can help subdividing and reach a point where only 2x2 cells max are intersected. Ok, so that's the rough idea I'm trying to push further. Sylvain already helped me and I'm hoping to steal more of his time when I'll have some code written. http://www-sop.inria.fr/reves/personnel/Sylvain.Lefebvre/ As I said, no code has been written yet so that's not even "a very early stage", that's more "non-existent" :-( Anyway... Along the line of those methods which sneakily try to turn rasterizing into ray-casting :-) Any feedback more than welcome ofcourse... Well, my take on the subject is exactly like yours, yoda:
“it would be just better to partition the screen in a few regions and apply regular projections on each area” :-) ))))

The general idea is to code an efficient “deformable” grid” which keep some good property:
- converge very fast to “area of interest” (a bit like amagnigying glass really)
- allow holes (or maybe not)
- stable over time (or maybe not…)

The “area of interest” are the stuff like the eye can see bits view from the light.

One big problem comes from the fact that once the grid is done then one has to render the polygon which can span over many cells. The geometry shader can help subdividing and reach a point where only 2×2 cells max are intersected.

Ok, so that’s the rough idea I’m trying to push further. Sylvain already helped me and I’m hoping to steal more of his time when I’ll have some code written.
http://www-sop.inria.fr/reves/personnel/Sylvain.Lefebvre/

As I said, no code has been written yet so that’s not even “a very early stage”, that’s more “non-existent” :-(
Anyway… Along the line of those methods which sneakily try to turn rasterizing into ray-casting :-)

Any feedback more than welcome ofcourse…

]]> By: Jim Tilander http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-36 Jim Tilander Wed, 12 Sep 2007 01:42:33 +0000 http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-36 SMM, Make sure that you get Marco drunk as well when he is down there, I've been trying now for a couple of months but it's hard. Maybe I'll give it one more try :) SMM,

Make sure that you get Marco drunk as well when he is down there, I’ve been trying now for a couple of months but it’s hard. Maybe I’ll give it one more try :)

]]> By: marco salvi http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-35 marco salvi Tue, 11 Sep 2007 17:42:03 +0000 http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-35 SMM, thanks for your invitation, I will surely pay a visit to Redwood City sooner or later. (I'm in half-crunch mode at the moment..) Purpledog: I had really bad experiences with warped projection schemes and I now think that it would be just better to partition the screen in a few regions and apply regular projections on each area (as ppl do with cascaded shadow maps..) Interested to hear about your own take on the subject anyway, any ETA for that? :) SMM, thanks for your invitation, I will surely pay a visit to Redwood City sooner or later. (I’m in half-crunch mode at the moment..)

Purpledog: I had really bad experiences with warped projection schemes and I now think that it would be just better to partition the screen in a few regions and apply regular projections on each area (as ppl do with cascaded shadow maps..)
Interested to hear about your own take on the subject anyway, any ETA for that? :)

]]> By: purpledog http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-34 purpledog Tue, 11 Sep 2007 09:03:17 +0000 http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-34 I'm between too jobs (well almost) and you can probably guess that from my peaking beyond3d activity. I'll have one month of "holydays" and two major projects: shadows and eternity 2. As soon as I have something to show I'll give you some hint. That's more along the line of "warped projection" as you call them. I'm manking good progress with eternity 2. http://uk.eternityii.com/try-eternity2-online I'm open to collaboration here :-) I’m between too jobs (well almost) and you can probably guess that from my peaking beyond3d activity. I’ll have one month of “holydays” and two major projects: shadows and eternity 2.

As soon as I have something to show I’ll give you some hint. That’s more along the line of “warped projection” as you call them.

I’m manking good progress with eternity 2.
http://uk.eternityii.com/try-eternity2-online
I’m open to collaboration here :-)

]]> By: ShootMyMonkey http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-33 ShootMyMonkey Tue, 11 Sep 2007 00:31:55 +0000 http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-33 Just as an update, I've been messing around with my hack a little bit, and I'm seeing it will pretty well need a nice load of thought and experimentation to look like I'd want it to... I'll have to play around with the interval construction and filtering methods to find something that works. Seems we're all in the same shoes. Scene complexity doesn't really make much difference in the behavior, and lower shadowmap resolution does decrease bleeding strength, but of course the same bleeding covers larger real estate. BTW Marco, if you ever feel the urge to head down to Redwood City and talk shop over a few beers, come on by. This is in NO WAY an attempt to try and get you into a drunken stupor so that you spill secrets more easily... nothing of the sort. :) Just as an update, I’ve been messing around with my hack a little bit, and I’m seeing it will pretty well need a nice load of thought and experimentation to look like I’d want it to… I’ll have to play around with the interval construction and filtering methods to find something that works. Seems we’re all in the same shoes.

Scene complexity doesn’t really make much difference in the behavior, and lower shadowmap resolution does decrease bleeding strength, but of course the same bleeding covers larger real estate.

BTW Marco, if you ever feel the urge to head down to Redwood City and talk shop over a few beers, come on by. This is in NO WAY an attempt to try and get you into a drunken stupor so that you spill secrets more easily… nothing of the sort. :)

]]> By: marco salvi http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-32 marco salvi Mon, 10 Sep 2007 04:29:30 +0000 http://pixelstoomany.wordpress.com/2007/09/03/a-not-so-little-teaser/#comment-32 It seems that even purpledog is working on something, hopefully he will spill some beans :) It seems that even purpledog is working on something, hopefully he will spill some beans :)

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