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Multiple Point Light Issue
Hi there, I'm a having a little trouble with using multiple point lights in my scene.
Here is the situation. My scene has 4 point lights in it and 1 directional light. For some reason, one of the point lights is always a lot dimmer than the rest (almost as if it is only rendering using vertex-based lighting, rather than pixel based lighting). When I turn up the intensity of the dim point light, it 'pops' into working again, and another one 'pops' to taking its place and being the dim one. When I then dim the same light, it pops back to being the dim one. The dim light also pops into life if ever the directional light's intensity ever reaches 0, and pops back off the moment the directional light intensity returns above 0. Ideally I don't want any dimmed out lights, I want them to work normally as they had just been created a new.
I have tried to use three different setups but all of them end up with this same result:
Setup1 Change the pixel light count to 6 and make all lights' render modes "Not Important"
Setup2 Change the pixel light count to 6 and make the directional light important, but the point lights Not Important.
Setup3 Change the pixel light count to 1 and only make the directional light important, and the other point lights Not Important.
Can anyone shed any light on what might be going wrong?
Much appreciated.
Xander
forward. I just looked at it with deferred, and that did sort it out. Could you maybe shed some light on why deferred works and forward doesnt? I am developing for mobile and am not sure which one I need to use yet. (I dont know a whole lot about the difference between deferred, and forward lighting. I know the vertex-lit vs pixel-based-lighting, but not on the specific of forward-vs-deferred).
Answer by equalsequals · Jun 20, 2013 at 08:35 PM
To elaborate on the comment I made, in the forward rendering path there are only a limited amount of pixel lights allowed, where in deferred all of the lighting is done per-pixel.
I recommend reading the references here: deferred and forward reference.
As an excerpt, this will explain the issue that you were describing:
In Forward Rendering, some number of brightest lights that affect each object are rendered in fully per-pixel lit mode. Then, up to 4 point lights are calculated per-vertex. The other lights are computed as Spherical Harmonics (SH), which is much faster but is only an approximation.
Unfortunately, the deferred pipeline is not currently supported on mobile, so you will need to use forward and SH lighting for dynamic lighting.
You may want to consider using a feature such as light probes in conjunction with light mapping to get better quality lighting at less cost if that is an option.
Hope that helps.
==
Sorry for commenting on an old post. I was also having the same issue and I switch the rendering mode to "important" on all point lights. This seems to have done the trick and now my point lights behave as expected but I fear I may be significantly compromising on performance? Have I made a rookie mistake?
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