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I would like to ask a few things on lights and lighting calculations in games. When i first bought a Riva TNT2 (my first card that supported multitexturing), i started reading on the subject. what''s the connection with the question, we''ll ask. Lightmaps. When i first implemented a lightmap generation algorithm (inspired by a demo found on the web, i think it was Al''s demo) i was very excited about how my scene looked. It was great. I extended the whole demo to support ellipsoids, except of sphere''s, for point lights, added ambient light for every BSP room, added directional spot lights, and (i think that) i have optimized the whole algorithms (to say the truth, it is a lot more slow than it can really be). Now to the question. A month ago i bought a GeForce card, and when i saw all the lighting effects that can be done with these cards, i started not to like my lightmaps at all. Do you understand what i mean...(???). So i''d like to know how things happens i games, what lighting methods they use, must i use OpenGL lighting (8 lights limit per scene) for best results etc. Thanks HellRaiZer. HellRaiZer

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a lot of games still use lightmaps eg UT2003,halo (in fact nearly every fps ever made)
not many games though use the hardware lights eg UT2003/quake3/doom3 etc (in fact i cant think of a single commerical one that uses them)
lightmapping is still the most used method of lighting a scene
next generation games (doom3) will have ditched lightmapping (but i wouldnt worry about this to much at present)

note u can use lightmapping and other lighting techniques together.

http://uk.geocities.com/sloppyturds/kea/kea.html
http://uk.geocities.com/sloppyturds/gotterdammerung.html

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Lightmaps work well in indoors enviroments, however, outdoors, in a landscape type engine, it might be a pain in the ass (unless you plan to calculate them on the spot, which, I belive, is slow).
With the hardware lights, the biggest problem is that they are only 8, and it''s not about 8 in a scene, but 8 NEAR the scene too, since a light''s effect can be visible even if it is outside of the scene.

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dont be so sad, i dont think your card can do what you did,
your system is still useful, those stupid 8 lights cant do the cool things as u can,
actually, the limit of hw light is 8 lights per triangle per pass, not 8 lights per sence
a few months ago, i asked it is not good enough to only have 8 lights in one sence,
and the answer is what do you do with more then 8 lights for one triangle or object

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Hello again... and thanks for the attention.

If all lighting in recent games is done using lightmaps, then i have a HUGE problem with them. Or there is a techique on to set up your lights in a scene. I know this a whole science on lighting in real life, but i want to know if they (professional game developers) are using parts of this science. Because if everything, lets say, in a SOF2 level is done using only lightmaps, then this is magic.

And if it is (or if it is not, i don''t care) magic, is there something for me to read on the subject, to learn as much as i can ????

In fewer words : I want something like a tutorial on lightmap construction in real-time, and something on scene lighting and things like that.

Thanks in advance.

HellRaiZer

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>>I want something like a tutorial on lightmap construction in real-time, and something on scene lighting and things like that<<

lightmaps are not generated ''realtime'' but are done in a precomputation stage (which can take a few hours),
the lights u see in q3a are also lm''s but only get drawn when a light is in the vicinity.
sorry i dont know of any tutorials.
btw dont expect this to be easy (i wouldnt attempt this unless u are very confident with your 3d graphics abilties)


http://uk.geocities.com/sloppyturds/kea/kea.html
http://uk.geocities.com/sloppyturds/gotterdammerung.html

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I believe http://www.gametutorials.com has a lightmapping tutorial for Quake3 bsp''s, try the last page of the OpenGL tutorials. It''s going to be using precomputed lightmaps, though, and not realtime.

----------------
Interesting quote deleted at request of owner

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Heeeeeeeeeeeeeeeeeeeeeeeeeeeelp !!!!!!!!!

I am in desperate need of RADIOSITY tutorials.
Please if you have something in mind please tell me.
Or if you have a scesific book, i''ll try to find it.

But i want something clear. Completely for beginners on the subject if possible. I don''t care about optimizated radiosity methods at the moment. I need some to run....

Thanks in advance...

HellRaiZer

HellRaiZer

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Huh, I don''t understand your logic:

At first you said:
"When i first implemented a lightmap generation algorithm (inspired by a demo found on the web, i think it was Al''s demo) i was very excited about how my scene looked. It was great.
"


And now:
"I am in desperate need of RADIOSITY tutorials."

Didn''t you say that you implemented radiosity into your engine a while ago?
Because that''s exactly how the lightmaps are precomputed.

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Lightmaps are just a method of storing the percalculated lighting for a scene in a texture for later use. Its not synonymous with radiosity, though most lightmap solutions do use that method.

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Sorry about the confusion...

When i said (in my first post) that i have made a lightmap calculator, i meant that lightmaps were calculated from point lights and spot lights. I think i had mentioned that. I don''t have a radiosity calculator. If you see Al''s demo you''ll understand what i mean. I don''t thing that lightmap calculations can only be done with radiosity.

So, because i searched the net for a descent tutorial on radiosity and i didn''t found anything with at least semi-complete pseudocode, except one called "Radiosity lighting tutorial" (i forgot the author), i want to know if there is something for beginners on the subject. The one i mentoned is ok but there is some details that are missing, like energy values for lights and recivers etc.

I think i made myself clearer (???????);

Please help on that. I need something to read...

Thanks again.

HellRaiZer

HellRaiZer

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I have the source for a radiosity calculator, but I don''t know where I did dl it so I''ve uploaded it to my ftp.

The program is written by Tobias Johansson, and if anybody knows his homepage adress he could maybe post it here as there were several interesting lighting/raytracing tuts and examples.

Download

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Hello again and sorry for the delay...

Thanks for the code.
But i think i must concetrate on something else for the time, because i think radiosity is a very advance topic for me.

Thanks again for your attention, and cu around!!!!!

HellRaiZer

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