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Blow up the lights / Support Voxel Based Global Illumination


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#1
microwerx

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Okay, this is probably too late to offer this one up. But I remember the whole radiosity advertised with Descent I and II. I loved how blowing up the lights and displays made the place darker (almost to your detriment, or perhaps in a multiplayer setting, advantage)... Anyways, as a graphics research guy, voxel based global illumination could be a great way of achieving this...

 

Oh, what about the auto map? Hopefully wire based?


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#2
Pixley

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While dynamic global illumination is something we'd love to have, unfortunately, there are a couple of reasons why we haven't been able to implement it:

 

  • UE4's Light Propagation Volume system (currently) does not scale.  It was built for human-scale environments, whereas Descent environments are many times that size (when we say our ships are ten meters across, we mean it!).  As such, performance would be exponentially worse in DU than in, say, Unreal Tournament or Fortnite.
  • UE4's LPV system also is (as stated by Epic) not ready for production.  It's missing several features that make it look substantially worse than the pre-computed lighting we currently use.

If these can be resolved, it would definitely be worth another look.  Alternatively, if Epic decides to go yet another route with global illumination (they've already tried and abandoned one approach), that would also be worthy of investigation.

 

As for the auto-map, it's definitely planned, but it will be some time before that will be implemented.  There are several technical hurdles that we'd need to overcome to develop that system in a way we'd be happy with.

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Even though I post in dev orange, that doesn't mean you should take my word as gospel. What I say is what I know at time of writing. Programming is, at all times, a learning experience. Things change.

#3
microwerx

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Since, I posted my message, I was doing some research because I had seen NVIDIA and Unreal essentially advertise VXGI. So, I was surprised when I couldn't find it in the editor. Sure enough, it was just a branch on the Unreal code which half makes me wonder if it is remotely ready for production. I'm going to play with it and see how it works -- mostly because it's related to some dissertation work I'm doing on GI algorithms.

 

I can imagine the technical hurdles for an auto-map system in modern 3D land. It's not the simple cube model from Descent of old where you essentially get an automap for free. Good luck with that though! I can't wait to see what you guys have envisioned for that.


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#4
Pixley

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VXGI specifically is part of NVidia's Gameworks package (which is why it's on its own fork of UE4), and may very well be production-ready.  That carries its own problems, as is the case with a lot of other Gameworks technologies:

  • Gameworks stuff runs poorly on AMD cards, which means we'd need to still have another lighting system in place for users with AMD cards.
  • Gameworks stuff is generally high-end, which means that we'd need another lighting system to support lower-spec computers.

As cool as it would be, the way things stand, it'd take a lot of resources to implement something like that, resources better spent on making the game better in other ways.

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Even though I post in dev orange, that doesn't mean you should take my word as gospel. What I say is what I know at time of writing. Programming is, at all times, a learning experience. Things change.

#5
microwerx

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Yea, you're spot on there. It'd definitely be better to work on the game in other ways. I can certainly appreciate how long it takes to build a realtime global illumination algorithm -- that works well on every manufacturer's video card. And from a game developer perspective, unless the GI algorithm is critical to the success of the game, it doesn't make sense to invest the extra time for that.

 

So are you guys depending on baked lighting for most of the illumination in the game, and then just point light sources for ships, items, etc?


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#6
Pixley

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The ships and power-ups use emissive textures (the ships only to a minor degree such that lighting from the environment still has an effect on them).  Baked lighting is done for the environment, and then everything else is lit dynamically, usually with spot lights.

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Even though I post in dev orange, that doesn't mean you should take my word as gospel. What I say is what I know at time of writing. Programming is, at all times, a learning experience. Things change.

#7
microwerx

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If, I'm right, emissive textures don't really affect local objects? As in the screenshot that I just put together in Unreal? I'm not trying to add this for a wish list at this point. I'm just curious how emissive textures are used in practice... I'll stop bugging you with the questions after this. =^D

 

Unreal%20Emissive%20Texture%20Test.png


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#8
microwerx

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For comparison, here is some older work I did with "local dynamic radiance maps" where I tested the idea of using cube maps to illuminate and shadow an environment. I just didn't know if anybody had been using something similar nowadays or not. It seems that this is still not used yet. I'll attribute the motivation honestly though to PSX Descent in the first place where my green lasers made the walls look green as they went flying down the corridor.

 

 

firesim_cuberadiance1.png

firesim_cuberadiance2.pngfiresim_shadow_fulllighting_normal.png


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