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Lighting

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1 comment, last by Sean123 22 years, 9 months ago
Hi, I had two questions about lighting and I am mostly talking about graphical appearance achieved with lighting so thats why I am posting in visual arts forum rather than programming. I''d really appreciate anyone''s help. - Is precalculated radiosity lightmaps worth the extra load time and effort when it comes to game design? How much of a difference does radiosity make vs. normal dynamic lights as used in most game? Is it true that radiosity increases realism alot? Is it worth all the trouble of precalculation and extra load time for the user? - Whats the difference between animated light and dynamic light? I tried doing some research but can''t quite understand what makes them different. As far as I can see, one is animated graphically while the other is programmed in the engine. What exactly is the difference? Do they both cast shadows, etc.? Thanks alot in advance, really appreciate it
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Well, I am not a specialist, but anyway I''ll try to answer your questions (I''m sure I''ll be corrected if I''m wrong):

-Yes, I think it''s really worth it, because somehow the brain is trained to get sceptical, if it sees a picture without radiosity on it. If you add radiosity, the obvious effect on the image might be small, but the lack of it is one of the things that let a picture look somehow ''artificial''.

-Well, afaik, the path of an animated light is fixed, so you can precalculate it''s effect on the static geometry into animated lightmaps. A lightbulb that swings might be a good example.
Dynamic lights could be also called animated as they most likely won''t be fixed, but unlike the animated lights they can freely move around and change their parameters according to the game, well dynamically. For example a rocket that lights a dark hall. You see, it is simply impossible to precalculate them(Ok, with some GB of RAM it may be not)!
And yes, both could cast shadows, etc. but always remember: dynamic lighting is calculation intensive...



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Dynamic lighting is expensive, but it''s not too bad if you only have a few dynamic lights. You should not try to calculate radiosity resulting from dynamic lights because it will be too slow. If you figure out how to do that write an article for gamedev. However radiosity is good for prerendered light maps, but it is not necessary because you can fake it. Faking it requires a lot of time and skill though and the best lighting artists will probably fake results that look better than the real thing. So it''s a good feature because it makes your life easier in the long run, but it is not a necessity.

Sean123. One thing that you say which is wrong is that precalculated light maps with radiosity increase the load time. Radiosity light maps and non radiosity light maps will load in the same amount of time. The radiosity and light map calculations should be done separately from loading the engine/game. There''s not need to force to user to wait for them to be calculated each time.

I don''t know what would be defined as an animated light, but Vaporisator''s explaination sounds good to me.

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