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Show HN: Browser-based light pollution simulator using real photometric data (iesna.eu)
conartist6 1 days ago [-]
I love the idea, but it feels very un-serious as an attempt to educate people or reduce light pollution, which makes me very sad as someone who cares about reducing light pollution :'(

Why can't I create any light pollution no matter what I do? The stars wink out when the light pollution is 1000x less bright than the stars. It just feels completely disconnected from what I know light pollution feels like.

If I may make a technical suggestion, accurately representing the "qualia" of what both the presence and absence of colorful light feels like on a monitor requires compressing the color space a bit. Take a gander at this: https://brandonli.net/spectra/doc/

conartist6 21 hours ago [-]
I suspect that another part of it is that you're accounting for the effect of the lights in the scene on the sky, but very few of the lights involved in light pollution will be lights that you can directly see -- the only evidence they exist will be from their upward scattering.

So here's the suggestion: there should be a "number of upward lights" slider which should influence an atmospheric light haze shader which, like real light pollution is brightest near the horizon. Then you could use a relatively real stellar skymap and give a sense of what it feels like to lose sight of the heavens, which is a kind of shocking thing to see, as well as what it might take to fix it.

holg 21 hours ago [-]
That's the real good proposal. I must admit, my focus was on the street lights, which in general are already almost good, compared to what you mention Thanks a lot
conartist6 21 hours ago [-]
Yeah the streetlights are great with that sodium carbide feeling. Having the sodium carbide horizon blend in with the sodium carbide buildings and trees and lamps will really sell the effect
holg 21 hours ago [-]
Yup, so actually my take as well is, the scene itself is imperfect, i took some known and easy to implement one. So some scene, where some high building is illuminated up, would be desirable...
holg 24 hours ago [-]
[flagged]
holg 1 days ago [-]
Ok, even so the quality degrades a lot, i added the webgl2 version, it shall load as fallback, if webgpu is not enabled, but can as well be enforced, to see the difference:

https://iesna.eu/?wasm=skyglow_demo&force=webgl2

holg 1 days ago [-]
I should have mentioned: WebGPU is needed, on Safari there is a bug in the Bevy Overlay, so you only see flickering (very annoying!) This is an upstream issue (on to it) So FF and Chrome works fine (if WebGPU is enabled!)
stereo 19 hours ago [-]
You’re going to get a lot of mobile iPhone users disappointed, since the main browser engine even in HN apps is Safari. Maybe a warning would encourage them to try the site elsewhere instead of closing it in disappointment?
jeroenhd 1 days ago [-]
All I get is an empty, dark blue page after I hit Launch Demo. Perhaps that does look a bit like a night sky, but I don't think that's what you're going for :)

Tested in Firefox/Brave/Chrome on Linux.

holg 1 days ago [-]
Thanks for the information, i should have mentioned, webgpu is explicitly used here, and this might be the issue! Bevy's usage of WebGL2 is not that mature, and i use Bindless rendering (from my own contribution)...
holg 1 days ago [-]
https://iesna.eu/?wasm=skyglow_demo&force=webgl2, tested on wsl2 ubuntu, sorry linux machine in the office :D
jeroenhd 49 minutes ago [-]
That works great, thanks!
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