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akyo

Lighting the scene help

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Hi guys, Whats best way to light a scene today considering, 1 light or more lights/spot lights? Not lightmaps, I dont want to use them. Also, how to determine what lights need to be used for a geometry in a scene? Is there any pre computation or what techniques are usually used? Thanks for replys.

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Quote:

Whats best way to light a scene today considering, 1 light or more lights/spot lights?

What's the best way depends on your goal, as always. Nowadays deferred rendering which allows you to render multiple lights in a single pass is quite trendy. Still point, spot and directional lights are common.

As an example, at the moment I use deferred rending with up to 50 lights displayed concurrendly.


Quote:

Also, how to determine what lights need to be used for a geometry in a scene? Is there any pre computation or what techniques are usually used?

Light culling is as important as geometry culling, but it depends on your rendering architecture. I would suggest to start with an easy approach, i.e. get all lights inside X units around your camera, order them by distance and display the closest Y lights.

From here you could start to improve the light culling:
1. Add priorities to your lights, disable low prio lights in favour of high prio lights which are farer away.
2. When you use a portal engine try to add information gathered from visible portals to increase or decrease a priority of a light.
3. Don't just turn displayed lights on/off, try to fade them in and out to avoid pop-up artifacts.

Good luck :)

--
Ashaman

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Don't forget-- you can drop some more lights by frustum culling their bounding volumes. This makes the most sense in a deferred shading context, but you could theoretically use it to optimize light selection for a forward shader.

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