This page should be merged with the Stencil Shadow Volumes page. —The preceding unsigned comment was added by Staz69uk ( talk • contribs) 23:41, 29 May 2005.
Merge completed from Stencil shadow volume and Carmack's Reverse, by Rainwarrior 22:59, 24 July 2006 (UTC)
We should have one diagram with the scene containing the 4 objects and a second diagram with the shadow volume (in this case it would be 3 disjoint shapes). The eye position should not be shown because the shadow volume is independant of it. -- Nic Roets 14:14, 2 September 2005 (UTC)
I've copied this message from my user talk page, as I think the discussion properly belongs here:
1. If by practical you mean "realtime", I would agree, but there are other applications than realtime. I've seen shadow mapping used in raytracing applications, which are definitely not limited to polygonal surfaces. ( [1] and [2], for instance)
2. I thought I've seen cases where polygons were discarded (rather than properly clipped) in the case where w=0, but I could be mistaken. I'll take your word for it that it works on all hardware, but I'll have to take a closer look at it myself. If you'd like to explain it, I'd welcome the explanation, as I don't know how clipping of coordinates with w=0 works at the hardware level. (I know how to accomplish it, mathematically speaking, but it was my belief that at least some hardware doesn't handle it properly because I thought I'd seen problems with it.)
3. If you don't put a front-cap on a depth pass shadow volume, you get the well known problem where the camera is inside shadow. Why would capping be unnecessary for depth pass?
I don't think I removed much of your added information. In many cases I rearranged sentences to make them shorter, but I don't really think of this as removing any thing. In other cases I thought you had removed simpler explanations in favour of more technical (closer to the implementation details) ones, and in those cases I tried to restore some of the original explanation and integrate into it those details you had added.
As for outright removals, I removed the term "shadow acne", because the term isn't applicable to shadow volumes (it should probably be mentioned at shadow mapping though). I also removed the reference to a specific GeForce card, as that kind of technical detail isn't very useful.
-- Rainwarrior 06:38, 26 October 2006 (UTC)
Tim's last name is currently spelled twice as "Heidmann" and once as "Heidemann." Could someone who knows which is correct change the article as appropriate? - Crater Creator 06:34, 25 May 2007 (UTC)
The paper listed here as being "Siggraph 2002" by Everitt and Kilgard was not actually a Siggraph paper: [3] - Nigels ( talk) 04:47, 30 May 2008 (UTC)
Do games other than id Tech 4 games use this method of shadowing? I havent seen this as much as Shadow maps. Can we have a list? —Preceding unsigned comment added by 99.246.160.46 ( talk) 05:19, 14 March 2010 (UTC)
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I was looking at the article, and it looks to me that it should be pretty trivial to do a shadow volume pass, without using stencil buffer with two passes using more modern shader approach. One can use a normal "color" like buffer (with signed integer or signed float to some extent), and fragment (pixel) shader, and simple additive blending for the buffer, and doing a SINGLE rendering pass with both front and back culling disabling, and emitting 1, or -1 (depending on a normal), inside fragment shader. I guess, it is so simple, that I am sure it must be known and utilized. Would be interesting to know if this is the case, and which title / developer used it first. But I can't really find any material on the matter. 2A02:168:F609:0:4F70:D338:7795:DADF ( talk) 22:11, 8 September 2019 (UTC)
Are there any examples of games engines that use shadow volumes? Aaronfranke ( talk) 00:53, 16 July 2020 (UTC)
Hi, just wanted to let you know that the last link to the Inquirer is dead (page no longer exists). Here's the text that was obviously referred to. Since the original source is no longer available, should we include the statement below in the external references page or main text or just drop the reference?
Franco De Bonis, audio sales marketing manager at Creative Labs Ireland, told the INQUIRER: " In our earlier graphics years (1999) we developed a technique for shadowing that is optimized. Recently "id" approached us informing us that they had used this technique in the development of DoomIII and had subsequently discovered that we owned the patent on it.
" Like any company Creative owns a number of technology patents and like any company we need to ensure that our patents are protected. Simply allowing another company to knowingly use a patent you own weakens your position and future claims against infringement. We therefore had to find a legally acceptable way to allow id to use this technique without it being seen as an infringement. The goal was the same from id's perspective".
Ghorwin ( talk) 06:10, 21 April 2021 (UTC)
Since OpenGL 2.0, usage of the function glStencilOpSeparate
allows stencil buffer shadows to take one less pass as geometry can be rendered once with the same result as a back-face and front-face pass. I am unsure of how widely used this method is, as shadow volumes as a whole seem not very common in modern renderers, but I was able to find one example on this GitHub repository at line 221 of
https://github.com/WeirdRubberDuck/TSBK03-Shadow-volumes/blob/master/main.cpp (633662cee17f6e22e560bf041a6da435a2aa11f1)
Although minor, this can be considered an optimization. Fekhesk ( talk) 21:52, 7 May 2023 (UTC)
This article is rated C-class on Wikipedia's
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This page should be merged with the Stencil Shadow Volumes page. —The preceding unsigned comment was added by Staz69uk ( talk • contribs) 23:41, 29 May 2005.
Merge completed from Stencil shadow volume and Carmack's Reverse, by Rainwarrior 22:59, 24 July 2006 (UTC)
We should have one diagram with the scene containing the 4 objects and a second diagram with the shadow volume (in this case it would be 3 disjoint shapes). The eye position should not be shown because the shadow volume is independant of it. -- Nic Roets 14:14, 2 September 2005 (UTC)
I've copied this message from my user talk page, as I think the discussion properly belongs here:
1. If by practical you mean "realtime", I would agree, but there are other applications than realtime. I've seen shadow mapping used in raytracing applications, which are definitely not limited to polygonal surfaces. ( [1] and [2], for instance)
2. I thought I've seen cases where polygons were discarded (rather than properly clipped) in the case where w=0, but I could be mistaken. I'll take your word for it that it works on all hardware, but I'll have to take a closer look at it myself. If you'd like to explain it, I'd welcome the explanation, as I don't know how clipping of coordinates with w=0 works at the hardware level. (I know how to accomplish it, mathematically speaking, but it was my belief that at least some hardware doesn't handle it properly because I thought I'd seen problems with it.)
3. If you don't put a front-cap on a depth pass shadow volume, you get the well known problem where the camera is inside shadow. Why would capping be unnecessary for depth pass?
I don't think I removed much of your added information. In many cases I rearranged sentences to make them shorter, but I don't really think of this as removing any thing. In other cases I thought you had removed simpler explanations in favour of more technical (closer to the implementation details) ones, and in those cases I tried to restore some of the original explanation and integrate into it those details you had added.
As for outright removals, I removed the term "shadow acne", because the term isn't applicable to shadow volumes (it should probably be mentioned at shadow mapping though). I also removed the reference to a specific GeForce card, as that kind of technical detail isn't very useful.
-- Rainwarrior 06:38, 26 October 2006 (UTC)
Tim's last name is currently spelled twice as "Heidmann" and once as "Heidemann." Could someone who knows which is correct change the article as appropriate? - Crater Creator 06:34, 25 May 2007 (UTC)
The paper listed here as being "Siggraph 2002" by Everitt and Kilgard was not actually a Siggraph paper: [3] - Nigels ( talk) 04:47, 30 May 2008 (UTC)
Do games other than id Tech 4 games use this method of shadowing? I havent seen this as much as Shadow maps. Can we have a list? —Preceding unsigned comment added by 99.246.160.46 ( talk) 05:19, 14 March 2010 (UTC)
Hello fellow Wikipedians,
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Cheers.— cyberbot II Talk to my owner:Online 04:02, 12 May 2016 (UTC)
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I have just modified 4 external links on Shadow volume. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
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Cheers.— InternetArchiveBot ( Report bug) 06:59, 4 September 2017 (UTC)
I was looking at the article, and it looks to me that it should be pretty trivial to do a shadow volume pass, without using stencil buffer with two passes using more modern shader approach. One can use a normal "color" like buffer (with signed integer or signed float to some extent), and fragment (pixel) shader, and simple additive blending for the buffer, and doing a SINGLE rendering pass with both front and back culling disabling, and emitting 1, or -1 (depending on a normal), inside fragment shader. I guess, it is so simple, that I am sure it must be known and utilized. Would be interesting to know if this is the case, and which title / developer used it first. But I can't really find any material on the matter. 2A02:168:F609:0:4F70:D338:7795:DADF ( talk) 22:11, 8 September 2019 (UTC)
Are there any examples of games engines that use shadow volumes? Aaronfranke ( talk) 00:53, 16 July 2020 (UTC)
Hi, just wanted to let you know that the last link to the Inquirer is dead (page no longer exists). Here's the text that was obviously referred to. Since the original source is no longer available, should we include the statement below in the external references page or main text or just drop the reference?
Franco De Bonis, audio sales marketing manager at Creative Labs Ireland, told the INQUIRER: " In our earlier graphics years (1999) we developed a technique for shadowing that is optimized. Recently "id" approached us informing us that they had used this technique in the development of DoomIII and had subsequently discovered that we owned the patent on it.
" Like any company Creative owns a number of technology patents and like any company we need to ensure that our patents are protected. Simply allowing another company to knowingly use a patent you own weakens your position and future claims against infringement. We therefore had to find a legally acceptable way to allow id to use this technique without it being seen as an infringement. The goal was the same from id's perspective".
Ghorwin ( talk) 06:10, 21 April 2021 (UTC)
Since OpenGL 2.0, usage of the function glStencilOpSeparate
allows stencil buffer shadows to take one less pass as geometry can be rendered once with the same result as a back-face and front-face pass. I am unsure of how widely used this method is, as shadow volumes as a whole seem not very common in modern renderers, but I was able to find one example on this GitHub repository at line 221 of
https://github.com/WeirdRubberDuck/TSBK03-Shadow-volumes/blob/master/main.cpp (633662cee17f6e22e560bf041a6da435a2aa11f1)
Although minor, this can be considered an optimization. Fekhesk ( talk) 21:52, 7 May 2023 (UTC)