Allow reflection probes to clip local lights
Cain Maven
Currently, local lights shine straight through objects. If you place a floor lamp in the corner of a room, you can either:
1) let the light bleed into all adjacent spaces, or
2) reduce the light radius -- which means the lamp isn't lighting up the room in a realistic fashion.
Given that most builds will most likely be equipped or retrofitted with per-room reflection probes, allowing the probes to serve as clipping volumes for any lights contained within them would solve the issue and allow for much greater realism and thereby immersion.
I am of course aware that this is not a perfect solution and other proposals favor casting shadows instead. However, this may be an easier solution that could be implemented sooner -- perhaps allowing a more complete solution to be deferred to and limited to glTF punctual lights.
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Kuuko Shan
I am all up for this too.
I just feel it may be complicated at time of viewing those lights OUTSIDE of their probe volume limits. Because you don't want them just vanishing when you leave the probe/room, but you can't either see them working "there" but not on your actual position. Only shadows seems the way to "clip" those lights into their right place.
Cain Maven
Kuuko Shan I do see your point, and proper shadows obviously is a more complete solution. But I don't think viewing from outside the room is going to be a problem; if the probe is aligned with a wall it _should_ clip the light -- otherwise it's up to users to place their lamps in a way that make sense. Like most things, this can be abused too :)
I still think it'd be an interesting solution to a two decades old problem -- and who knows, maybe it could be used for some interesting effects, too?
Kuuko Shan
Cain Maven that's the thing, clipping local lights may not be as simple as we think and it could potentially lead to a big performance impact. The case of probes is a bit different, they are built to work in that way. But lights... it's a different thing.
Don't get me wrong, it is not like I don't like the idea. I really want it to happen. And maybe it is easier and simpler to implement than I think. But I also like to think about the downsides and the issues that a new feature could face at the time of being implemented, at the time of being realistic about seeing it happening. And something tells me that we are missing something that would make this quite more complex than we think.
Cain Maven
Kuuko Shan Nothing is easy :) We'll see what the Lab say.
The appeal for me is vastly increased realism sooner rather than later.
Kuuko Shan
Cain Maven yeah I always hated all the specular leaks everywhere. I just don't recall seeing a solution for this in Unity or Unreal other than the usage of occlusion maps either baked in the object like we do now or baked into the whole environment for those with static lighting.
Hopefully they can come with something. Long ago Davep mentioned about being possible to occlude lights without using shadows as this issue has been mentioned before. But nothing else has been said. I am fine with whatever solution as long as it works good enough.