4 ms·

It should be more like "how to find a shadow in a room full of mirrors", shouldn't it? Which is even more amazing.

• lmilcin 5y ago
  Well... no. These are two separate problems. This example doesn't show all places where the shadow is. It only shows, when you place yourself and a light, an example arrangement of occluders that will prevent you from being hit.
  • akdor1154 5y ago
    Why are they separate problems? Maybe I should have phrased "how to create a complete shadow in a room full of mirrors".
  • SamBam 5y ago
    > This example doesn't show all places where the shadow is. I'm curious. Does it not? Because, from the descriptions of how to place all the blockers in order to create a shadow on that one spot, it did seem to me as if that one spot would be the only shadow in the room. With 16 blockers can you have more that one discrete shadow?
    • lmilcin 5y ago
      Have you proven there is going to be only one shadow? Is it possible there are symmetries? I tell you that these are two different problems, just read it again: 1, given light source and an object, find position of occluders so that the object is never illuminated and 2, given light source and occluders, find all places that are not getting illuminated,
• NKosmatos 5y ago
  There was an interactive web page where you could place single point light sources and obstacles freely in a 2D room and then see in real time the shadows and where are the safe points. Too bad I can't remember the URL and can't find this old page. Anyone has a link to share?
  • NKosmatos 5y ago
    The closest I've found is this one, but it's not what I was referring to: https://ricktu288.github.io/ray-optics/ https://ricktu288.github.io/ray-optics/
  • etherblood 5y ago
    Maybe you mean this? https://www.redblobgames.com/articles/visibility/ https://www.redblobgames.com/articles/visibility/
    • NKosmatos 5y ago
      Yes, thank you :-)