4 ms·

Incredible, but I don’t see a way to quickly figure out what the safe spot would be given any configuration of a room.

by xwdv 5y ago

deleted 5y ago
[deleted]
jekub 5y ago
It works the other way, the shooter position is fixed as well as your position. Your are allowed to place a finite amount of blockers to make your position safe. The video comment say that it is always possible to make your place safe with at most 16 blockers. There is a link to the actual code used.
- makach 5y ago
  Does this also work in a 3D environment?
  - jonas21 5y ago
    Yes, but you'd need up to 64 obstacles.
    - lupire 5y ago
      does it work in a 1D environment? yes, 1 blocker. does it work in a 4D environment?
      - SamBam 5y ago
        Sure, a time blocker that is placed before the laser is ever turned on.
mitko 5y ago
You could try projecting rays from start through the obstacles to see where they intersect after a limited number of reflections. This should narrow it to a few candidate spots
mehwoot 5y ago
There isn't always a safe spot, but you can generate a room that makes a safe spot- https://www.youtube.com/watch?v=jJ6FD59U0_E https://www.youtube.com/watch?v=jJ6FD59U0_E
- laurent92 5y ago
  The area covered by the lasers should remain painted, so we could see all the spots which haven’t been hit ever.
tdeck 5y ago
I'm curious why you couldn't just surround yourself with the 16 objects. Perhaps they're meant to be much smaller than the person?
- ordu 5y ago
  This way allow you to hide. A tight group of obstacles will give away your position and it will be demolished with a bazooka. Though an attacker might calculate the possible location of your body and use a grenade. But it might be unsafe for himself.
- neitherboosh 5y ago
  The posted solution seems to work even when the objects have zero area, and are just points in space. If you just surrounded the target with 16 points, there would either be gaps or the points would be infinitesimally close to the target and would occupy the same space.
  - ric2b 5y ago
    So that means that any possible laser coming out of the shooter's position eventually passes through one of these 16 specific infinitesimally small points _before_ ever hitting the target? And that is always possible for any position of shooter and target? That's bonkers, wow.
- Pyramus 5y ago
  Both person and obstacles are meant to be infinitesimally small, i.e. points with mass zero, which makes one really appreciate the beauty of the solution.
bunabhucan 5y ago
This video explains it. His pinned comment explains the mod arithmetic: https://www.youtube.com/watch?v=jJ6FD59U0_E https://www.youtube.com/watch?v=jJ6FD59U0_E
- parhamn 5y ago
  Thanks for the share! I took some quick (read, not proof-read) snippets on this if anyone wants to see: https://synth.app/s/uiElJvnnk https://synth.app/s/uiElJvnnk
- Pyramus 5y ago
  I wish he had explained the mod arithmetic more, the periodicity of 4 is really at the heart of the solution.

Incredible, but I don’t see a way to quickly figure out what the safe spot would be given any configuration of a room.

by xwdv 5y ago

Incredible, but I don’t see a way to quickly figure out what the safe spot would be given any configuration of a room.

deleted 5y ago

[deleted]

jekub 5y ago

It works the other way, the shooter position is fixed as well as your position. Your are allowed to place a finite amount of blockers to make your position safe. The video comment say that it is always possible to make your place safe with at most 16 blockers. There is a link to the actual code used.

makach 5y ago
Does this also work in a 3D environment?
- jonas21 5y ago
  Yes, but you'd need up to 64 obstacles.
  - lupire 5y ago
    does it work in a 1D environment? yes, 1 blocker. does it work in a 4D environment?
    - SamBam 5y ago
      Sure, a time blocker that is placed before the laser is ever turned on.

mitko 5y ago

You could try projecting rays from start through the obstacles to see where they intersect after a limited number of reflections. This should narrow it to a few candidate spots

mehwoot 5y ago

There isn't always a safe spot, but you can generate a room that makes a safe spot- https://www.youtube.com/watch?v=jJ6FD59U0_E https://www.youtube.com/watch?v=jJ6FD59U0_E

laurent92 5y ago
The area covered by the lasers should remain painted, so we could see all the spots which haven’t been hit ever.

tdeck 5y ago

I'm curious why you couldn't just surround yourself with the 16 objects. Perhaps they're meant to be much smaller than the person?

ordu 5y ago
This way allow you to hide. A tight group of obstacles will give away your position and it will be demolished with a bazooka. Though an attacker might calculate the possible location of your body and use a grenade. But it might be unsafe for himself.
neitherboosh 5y ago
The posted solution seems to work even when the objects have zero area, and are just points in space. If you just surrounded the target with 16 points, there would either be gaps or the points would be infinitesimally close to the target and would occupy the same space.
- ric2b 5y ago
  So that means that any possible laser coming out of the shooter's position eventually passes through one of these 16 specific infinitesimally small points _before_ ever hitting the target? And that is always possible for any position of shooter and target? That's bonkers, wow.
Pyramus 5y ago
Both person and obstacles are meant to be infinitesimally small, i.e. points with mass zero, which makes one really appreciate the beauty of the solution.

bunabhucan 5y ago

This video explains it. His pinned comment explains the mod arithmetic: https://www.youtube.com/watch?v=jJ6FD59U0_E https://www.youtube.com/watch?v=jJ6FD59U0_E

parhamn 5y ago
Thanks for the share! I took some quick (read, not proof-read) snippets on this if anyone wants to see: https://synth.app/s/uiElJvnnk https://synth.app/s/uiElJvnnk
Pyramus 5y ago
I wish he had explained the mod arithmetic more, the periodicity of 4 is really at the heart of the solution.