## Re: [Algorithms] Extracting Lights from a Dynamic SH Light Environment

 Re: [Algorithms] Extracting Lights from a Dynamic SH Light Environment From: Martin Ecker - 2007-03-01 17:32:44 ```Hi, Willem de Boer wrote: > Here's one thing I don't understand: >=20 > "But when we move closer to e.g. the red light, we're suddenly > extracting two red lights from the direction of the red light." > > How is it possible to move 'closer' to a directional lightsource? Surely > this assumption of being able to move closer must have something to do > with you getting the maths mixed up? Well, we still have point lights and other types of lights in the scene, so when we move closer to them the direction of the directional light we project to SH for that point light changes. Also the intensity changes depending on the point light's radial falloff. > One question to you though. Since you are trying to extract directional > light- > sources from an SH projection that you've generated from the directional > light sources yourself, is it not possible to retain these original > lightsources > instead of trying to extract them? > It would save you a great amount of hassle that way. Yes, that's what we're trying to do now actually. Thanks, Martin ```

 Re: [Algorithms] Extracting Lights from a Dynamic SH Light Environment From: Martin Ecker - 2007-03-01 17:32:44 ```Hi, Willem de Boer wrote: > Here's one thing I don't understand: >=20 > "But when we move closer to e.g. the red light, we're suddenly > extracting two red lights from the direction of the red light." > > How is it possible to move 'closer' to a directional lightsource? Surely > this assumption of being able to move closer must have something to do > with you getting the maths mixed up? Well, we still have point lights and other types of lights in the scene, so when we move closer to them the direction of the directional light we project to SH for that point light changes. Also the intensity changes depending on the point light's radial falloff. > One question to you though. Since you are trying to extract directional > light- > sources from an SH projection that you've generated from the directional > light sources yourself, is it not possible to retain these original > lightsources > instead of trying to extract them? > It would save you a great amount of hassle that way. Yes, that's what we're trying to do now actually. Thanks, Martin ```
 Re: [Algorithms] Extracting Lights from a Dynamic SH Light Environment From: Martin Ecker - 2007-03-01 17:39:05 ```Willem de Boer wrote: > How is it possible to move 'closer' to a directional lightsource? Surely > this assumption of being able to move closer must have something to do > with you getting the maths mixed up? Also, I just realized that I messed up the example I gave in my initial email.=20 I meant: "As an example, imagine a character standing in between two point (not directional!) lights, a green light from the left and a red light from the right" Martin ```
 Re: [Algorithms] Extracting Lights from a Dynamic SH LightEnvironment From: Tom Forsyth - 2007-03-01 18:12:34 ```Turning lights into SHs into lights is kinda goofy :-) I recently wrote = a follow-up to my GDC2003 talk that is about exactly this - how to = separate a lighting environment into a few real lights and an SH for things like characters. (watch out for page line wrapping) http://www.eelpi.gotdns.org/blog.wiki.html#%5B%5BSpherical%20Harmonics%20= in% 20Actual%20Games%20notes%5D%5D TomF. > -----Original Message----- > From: gdalgorithms-list-bounces@...=20 > [mailto:gdalgorithms-list-bounces@...] On=20 > Behalf Of Martin Ecker > Sent: 01 March 2007 09:33 > To: Game Development Algorithms > Subject: Re: [Algorithms] Extracting Lights from a Dynamic SH=20 > LightEnvironment >=20 >=20 > Hi, >=20 > Willem de Boer wrote: > > Here's one thing I don't understand: > >=20 > > "But when we move closer to e.g. the red light, we're suddenly > > extracting two red lights from the direction of the red light." > > > > How is it possible to move 'closer' to a directional lightsource? > Surely > > this assumption of being able to move closer must have=20 > something to do > > with you getting the maths mixed up? >=20 > Well, we still have point lights and other types of lights in=20 > the scene, > so when we move closer to them the direction of the=20 > directional light we > project to SH for that point light changes. Also the intensity changes > depending on the point light's radial falloff. >=20 > > One question to you though. Since you are trying to extract > directional > > light- > > sources from an SH projection that you've generated from the > directional > > light sources yourself, is it not possible to retain these original > > lightsources > > instead of trying to extract them? > > It would save you a great amount of hassle that way. >=20 > Yes, that's what we're trying to do now actually. >=20 > Thanks, > Martin >=20 >=20 > -------------------------------------------------------------- > ----------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the=20 > chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=3Djoin.php&p=3Dsourceforge &CID=3DDEVDEV _______________________________________________ GDAlgorithms-list mailing list GDAlgorithms-list@... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=3D6188 --=20 No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.3/700 - Release Date: = 24/02/2007 20:14 =20 --=20 No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.3/700 - Release Date: = 24/02/2007 20:14 =20 ```
 Re: [Algorithms] Extracting Lights from a Dynamic SHLightEnvironment From: Brubaker, Pete - 2007-03-01 18:40:28 ```Well I partially agree with this... If you have the real lights, and you are projecting them into SH, why don't you use the real lights to find out the "brightest" lights? Then project the remainder of the lights into SH.. Think of it like this. You have a bunch of lights. You render them into a light map texture on a sphere, then you want to use that texture to find the brightest lights. Even though you had the lights to begin with. Seems kind of backwards to me. Do have the 'real' lights available to you in the engine? -----Original Message----- From: gdalgorithms-list-bounces@... [mailto:gdalgorithms-list-bounces@...] On Behalf Of Tom Forsyth Sent: Thursday, March 01, 2007 10:13 AM To: 'Game Development Algorithms' Subject: Re: [Algorithms] Extracting Lights from a Dynamic SHLightEnvironment Turning lights into SHs into lights is kinda goofy :-) I recently wrote a follow-up to my GDC2003 talk that is about exactly this - how to separate a lighting environment into a few real lights and an SH for things like characters. (watch out for page line wrapping) http://www.eelpi.gotdns.org/blog.wiki.html#%5B%5BSpherical%20Harmonics%2 0in% 20Actual%20Games%20notes%5D%5D TomF. > -----Original Message----- > From: gdalgorithms-list-bounces@... > [mailto:gdalgorithms-list-bounces@...] On Behalf Of=20 > Martin Ecker > Sent: 01 March 2007 09:33 > To: Game Development Algorithms > Subject: Re: [Algorithms] Extracting Lights from a Dynamic SH=20 > LightEnvironment >=20 >=20 > Hi, >=20 > Willem de Boer wrote: > > Here's one thing I don't understand: > >=20 > > "But when we move closer to e.g. the red light, we're suddenly=20 > > extracting two red lights from the direction of the red light." > > > > How is it possible to move 'closer' to a directional lightsource? > Surely > > this assumption of being able to move closer must have > something to do > > with you getting the maths mixed up? >=20 > Well, we still have point lights and other types of lights in the=20 > scene, so when we move closer to them the direction of the directional > light we project to SH for that point light changes. Also the=20 > intensity changes depending on the point light's radial falloff. >=20 > > One question to you though. Since you are trying to extract > directional > > light- > > sources from an SH projection that you've generated from the > directional > > light sources yourself, is it not possible to retain these original=20 > > lightsources instead of trying to extract them? > > It would save you a great amount of hassle that way. >=20 > Yes, that's what we're trying to do now actually. >=20 > Thanks, > Martin >=20 >=20 > -------------------------------------------------------------- > ----------- > Take Surveys. Earn Cash. Influence the Future of IT Join=20 > SourceForge.net's Techsay panel and you'll get the chance to share=20 > your opinions on IT & business topics through brief surveys-and earn=20 > cash = http://www.techsay.com/default.php?page=3Djoin.php&p=3Dsourceforge &CID=3DDEVDEV _______________________________________________ GDAlgorithms-list mailing list GDAlgorithms-list@... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=3D6188 -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.3/700 - Release Date: 24/02/2007 20:14 =20 --=20 No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.3/700 - Release Date: 24/02/2007 20:14 =20 ------------------------------------------------------------------------ - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=3Djoin.php&p=3Dsourceforge&CID=3D= DEVDE V _______________________________________________ GDAlgorithms-list mailing list GDAlgorithms-list@... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=3D6188 ```