Jump to content
  • Advertisement

Archived

This topic is now archived and is closed to further replies.

HellRaiZer

Light Please...

This topic is 5773 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

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

Share this post


Link to post
Share on other sites
Advertisement
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

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
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

Share this post


Link to post
Share on other sites
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

Share this post


Link to post
Share on other sites
>>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

Share this post


Link to post
Share on other sites
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

Share this post


Link to post
Share on other sites
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

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!