## RE: [Algorithms] Bump maps and ambient light

 RE: [Algorithms] Bump maps and ambient light From: Warrick Buchanan - 2002-11-11 15:54:45 ```How about a cubemap for the ambient only area, encoding 'ambient' light = vectors in it? Warrick. -----Original Message----- From: Gottfried Chen [mailto:gottfried.chen@...] Sent: 11 November 2002 15:46 To: gdalgorithms-list@... Subject: [Algorithms] Bump maps and ambient light When you use bump maps from a higher poly model and the model is placed into an area with ambient light only then there's the problem that the detail in this area is a lot lower then in lit places. What are good ways to solve this? - Don't use ambient light (that's not possible for what we're doing, since we'd get big dark areas). - Use a texture that has the detail painted into and switch/fade to this texture when you can't use dot3 lighting, though I don't think this'll look good. - Light the model from a default direction in ambient only places. Gottfried ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ GDAlgorithms-list mailing list GDAlgorithms-list@... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_ida88 ```

 RE: [Algorithms] Bump maps and ambient light From: Warrick Buchanan - 2002-11-11 15:54:45 ```How about a cubemap for the ambient only area, encoding 'ambient' light = vectors in it? Warrick. -----Original Message----- From: Gottfried Chen [mailto:gottfried.chen@...] Sent: 11 November 2002 15:46 To: gdalgorithms-list@... Subject: [Algorithms] Bump maps and ambient light When you use bump maps from a higher poly model and the model is placed into an area with ambient light only then there's the problem that the detail in this area is a lot lower then in lit places. What are good ways to solve this? - Don't use ambient light (that's not possible for what we're doing, since we'd get big dark areas). - Use a texture that has the detail painted into and switch/fade to this texture when you can't use dot3 lighting, though I don't think this'll look good. - Light the model from a default direction in ambient only places. Gottfried ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ GDAlgorithms-list mailing list GDAlgorithms-list@... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_ida88 ```
 RE: [Algorithms] Bump maps and ambient light From: Warrick Buchanan - 2002-11-11 16:20:11 ```Of course the real issue is in these areas what is the ambient light due = to? Sunlight? (Then you just have a directional light) and/or just = general surface scattering? If it can't be simulated reasonably with a = combination of 'standard' light types consider as I said a cubemap or a = simple 2d texture lookup function depending on its nature. You could = also take a lumigraph approach and use a 3d texture... ;) Warrick. -----Original Message----- From: Justin Heyes-Jones [mailto:justin.heyesjones@...] Sent: 11 November 2002 16:04 To: gdalgorithms-list@... Subject: Re: [Algorithms] Bump maps and ambient light As you suggest, you should be able to use either default or randomly = created directional light of the same colour as your ambient light in areas = without any directional light. ----- Original Message ----- From: "Gottfried Chen" To: Sent: Monday, November 11, 2002 3:46 PM Subject: [Algorithms] Bump maps and ambient light When you use bump maps from a higher poly model and the model is placed into an area with ambient light only then there's the problem that the detail in this area is a lot lower then in lit places. What are good ways to solve this? - Don't use ambient light (that's not possible for what we're doing, since we'd get big dark areas). - Use a texture that has the detail painted into and switch/fade to this texture when you can't use dot3 lighting, though I don't think this'll look good. - Light the model from a default direction in ambient only places. Gottfried ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ GDAlgorithms-list mailing list GDAlgorithms-list@... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_ida88 ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ GDAlgorithms-list mailing list GDAlgorithms-list@... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=3D6188 ```
 RE: [Algorithms] Bump maps and ambient light From: Simon O'Connor - 2002-11-11 16:42:08 ```Hmm, an interesting problem. I've not tested either of these (so they might look terrible...), but: Maybe you could have a model/texture space directional light (assuming the source of the ambient is from local diffuse reflection), i.e. follow the model/polys around so the light doesn't change as the model moves. Or a possible 'hack' - use the Z or Y component of the normal map directly (maybe with some scaling/biasing etc) as the ambient intensity. Simon O'Connor Creative Asylum Limited http://www.creative-asylum.com > -----Original Message----- > From: Justin Heyes-Jones [mailto:justin.heyesjones@...] > Sent: 11 November 2002 16:04 > To: gdalgorithms-list@... > Subject: Re: [Algorithms] Bump maps and ambient light > > > As you suggest, you should be able to use either default or > randomly created > directional light of the same colour as your ambient light in > areas without > any directional light. > > ----- Original Message ----- > From: "Gottfried Chen" > To: > Sent: Monday, November 11, 2002 3:46 PM > Subject: [Algorithms] Bump maps and ambient light > > > When you use bump maps from a higher poly model and the model > is placed > into an area with ambient light only then there's the problem that the > detail in this area is a lot lower then in lit places. What are good > ways to solve this? > > - Don't use ambient light (that's not possible for what we're doing, > since we'd get big dark areas). > - Use a texture that has the detail painted into and > switch/fade to this > texture when you can't use dot3 lighting, though I don't think this'll > look good. > - Light the model from a default direction in ambient only places. > > Gottfried > > > ------------------------------------------------------- > This sf.net email is sponsored by:ThinkGeek > Welcome to geek heaven. > http://thinkgeek.com/sf > _______________________________________________ > GDAlgorithms-list mailing list > GDAlgorithms-list@... > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list > Archives: > http://sourceforge.net/mailarchive/forum.php?forum_ida88 > > > > > > > ------------------------------------------------------- > This sf.net email is sponsored by:ThinkGeek > Welcome to geek heaven. > http://thinkgeek.com/sf > _______________________________________________ > GDAlgorithms-list mailing list > GDAlgorithms-list@... > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list > Archives: > http://sourceforge.net/mailarchive/forum.php?forum_id=6188 > ```
 RE: [Algorithms] Bump maps and ambient light From: Dan Baker - 2002-11-12 06:49:49 ```You can use the hemisphere lighting trick, works great for these scenarios i.e. use a 2 color ambient term, one is the sky color, the other is the ground color. Take the dot product between the normal and the vertical (0,0,1), rerange it to go from 0 to 1 (instead of -1 to 1) and then lerp between the sky and ground color. Technically (if you work the integral of a 2 hemisphere lighting model), its supposed to be the sin, not the cos, but its hard to tell the difference.=20 -Dan -----Original Message----- From: Gottfried Chen [mailto:gottfried.chen@...]=20 Sent: Monday, November 11, 2002 7:46 AM To: gdalgorithms-list@... Subject: [Algorithms] Bump maps and ambient light When you use bump maps from a higher poly model and the model is placed into an area with ambient light only then there's the problem that the detail in this area is a lot lower then in lit places. What are good ways to solve this? - Don't use ambient light (that's not possible for what we're doing, since we'd get big dark areas). - Use a texture that has the detail painted into and switch/fade to this texture when you can't use dot3 lighting, though I don't think this'll look good. - Light the model from a default direction in ambient only places. Gottfried ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ GDAlgorithms-list mailing list GDAlgorithms-list@... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_ida88 ```
 RE: [Algorithms] Bump maps and ambient light From: Tom Forsyth - 2002-11-13 14:38:26 ```For Blade 2 we turned the artist-set ambient shade into 50% actual ambient and 50% directional light coming from above. Even though there were no scenes with daylight in (what with them being vampires and all), we're so used to light coming mainly from above that it looked just fine, and you still got plenty of details with a 50/50 split. Tom Forsyth - Muckyfoot bloke and Microsoft MVP. This email is the product of your deranged imagination, and does not in any way imply existence of the author. > -----Original Message----- > From: Gottfried Chen [mailto:gottfried.chen@...] > Sent: 11 November 2002 15:46 > To: gdalgorithms-list@... > Subject: [Algorithms] Bump maps and ambient light > > > When you use bump maps from a higher poly model and the model > is placed > into an area with ambient light only then there's the problem that the > detail in this area is a lot lower then in lit places. What are good > ways to solve this? > > - Don't use ambient light (that's not possible for what we're doing, > since we'd get big dark areas). > - Use a texture that has the detail painted into and > switch/fade to this > texture when you can't use dot3 lighting, though I don't think this'll > look good. > - Light the model from a default direction in ambient only places. > > Gottfried ```
 RE: [Algorithms] Bump maps and ambient light From: Dan Baker - 2002-11-14 00:37:02 ```If you think of ambient as a an approximation of a global illumination = term (which it is), then the hemisphere trick is just a much better = approximation of the global illumination term which looks _vastly_ = better then ambient. The idea is that each element of the surface is lit = by a hemisphere of incoming light. (i.e. half of an enviroment cube = map). Bump detail comes right out it with this techinique. The Xbox game = Shrek used this alot. If you take an average diffuse environment from an average scene (i.e. = integrate the envmap), you'll find that it is quite smooth - you can = model it fairly well with just 2 colors, the sky and ground color. Then = use the trick I described before to mix them. This is fairly close to = the 'correct' solution, but we found it is good to precompute an = occlusion term so that pits and valleys get darkened since they can't = get received the whole % of light from the hemisphere.=20 -Dan -----Original Message----- From: Gottfried Chen [mailto:gottfried.chen@...]=20 Sent: Tuesday, November 12, 2002 2:01 AM To: gdalgorithms-list@... Subject: AW: [Algorithms] Bump maps and ambient light What we currently do and looks ok: The color texture contains all = details painted in but lit with ambient light only (so no particular = light direction is assumed and the contrast is low). So even when there = is no directional/point light, no details pop away and plain ambient = lighting is used. It still looks a bit flat but I think it's more = correct than assuming any light direction in ambient only cases. Gottfried > -----Urspr=FCngliche Nachricht----- > Von: Dan Baker [mailto:danbaker@...]=20 > Gesendet: Dienstag, 12. November 2002 07:50 > An: gdalgorithms-list@... > Betreff: RE: [Algorithms] Bump maps and ambient light >=20 >=20 > You can use the hemisphere lighting trick, works great for=20 > these scenarios >=20 > i.e. use a 2 color ambient term, one is the sky color, the=20 > other is the ground color. Take the dot product between the=20 > normal and the vertical (0,0,1), rerange it to go from 0 to 1=20 > (instead of -1 to 1) and then lerp between the sky and ground color. >=20 > Technically (if you work the integral of a 2 hemisphere=20 > lighting model), its supposed to be the sin, not the cos, but=20 > its hard to tell the difference.=20 >=20 > -Dan >=20 > -----Original Message----- > From: Gottfried Chen [mailto:gottfried.chen@...]=20 > Sent: Monday, November 11, 2002 7:46 AM > To: gdalgorithms-list@... > Subject: [Algorithms] Bump maps and ambient light >=20 > When you use bump maps from a higher poly model and the model=20 > is placed into an area with ambient light only then there's=20 > the problem that the detail in this area is a lot lower then=20 > in lit places. What are good ways to solve this? >=20 > - Don't use ambient light (that's not possible for what we're=20 > doing, since we'd get big dark areas). > - Use a texture that has the detail painted into and=20 > switch/fade to this texture when you can't use dot3 lighting,=20 > though I don't think this'll look good. > - Light the model from a default direction in ambient only places. >=20 > Gottfried >=20 >=20 > ------------------------------------------------------- > This sf.net email is sponsored by:ThinkGeek > Welcome to geek heaven. > http://thinkgeek.com/sf=20 > _______________________________________________ > GDAlgorithms-list mailing list GDAlgorithms-list@... > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list > Archives: http://sourceforge.net/mailarchive/forum.php?forum_ida88 >=20 >=20 > ------------------------------------------------------- > This sf.net email is sponsored by:ThinkGeek > Welcome to geek heaven. > http://thinkgeek.com/sf=20 > _______________________________________________ > GDAlgorithms-list mailing list GDAlgorithms-list@... > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list > Archives: http://sourceforge.net/mailarchive/forum.php?forum_ida88 >=20 ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ GDAlgorithms-list mailing list GDAlgorithms-list@... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_ida88 ```