3 ms·

I'm quite curious as to whether the speed of light across the game space decreases instantaneously when you pick up an orb or whether the change in the speed of

I'm quite curious as to whether the speed of light across the game space decreases instantaneously when you pick up an orb or whether the change in the speed of light propagates at the speed of... umm light. Also they definitely need to have a black hole or 2 chucked in and maybe some miniature binary stars orbiting at relativistic speeds

Gring 14y ago
Since the speed of light doesn't change in real life, and there is no answer at what speed a changing speed of light would propagate in real life, does it really matter how it's implemented in this game? My guess is that they took the easiest route and made it change instantaneously for the whole world.
- sp332 14y ago
  > does it really matter how it's implemented in this game? Yes, I imagine it would affect gameplay quite a bit.
  - egypturnash 14y ago
    The various visual effects seem to be render-time transforms, so I suspect the speed change is propagating instantly across the gameworld. Can you think of a way to model a non-instantaneous propagation of this change that doesn't involve simulating oodles of photons wandering around the world?
    - Groxx 14y ago
      Yes. Light from source A travels at the speed determined by the last speed-wavefront that passed it. This can be modeled by storing the speed on the sources, or by calculating from all gathered orbs in the world, and selecting the most-recent, when the time is calculated by (<time picked up> at <distance when picked up> at <speed of light before picked up>). All such waves will be entirely contained within the previous wave because you cannot go faster than light and the speed only decreases, so all that matters is the speed before it was picked up, which is the speed the wave-front moves at (or does it move at the new speed? eh, pick either one, it doesn't matter.) Then, for each orb picked up since the most-recent that affected the source, the time for the light to reach the observer is based on <distance to orb N> at speed <before orb N> until <distance to orb N-1>. Then repeat for orb N-1 until you run out of orbs. In this case, N would be the oldest orb whose wavefront has not yet passed the source. It's a piece-wise calculation (the reverse of what's described), so it would be slower than instantaneous changes, but there's no need to model photons. And I would guess there's a reasonably-efficient way to calculate this on a GPU, so it could probably be real-time. Or it will be in a year or two.
m_darkTemplar 14y ago
It's instantaneous. There's no answer in physics for what should happen when you change the speed of light because that simply just can't happen. Therefore we didn't bother doing something like prorogation at the speed of light. We don't do gravity calculations, along with a few other things because we didn't have time and they make the other effects hard to see. In the future I would have liked to continue with the project and implement some of this though.
- astrobe_ 14y ago
  Cannot happen? Would we able to detect it if it actually did happen?

Gring 14y ago

Since the speed of light doesn't change in real life, and there is no answer at what speed a changing speed of light would propagate in real life, does it really matter how it's implemented in this game? My guess is that they took the easiest route and made it change instantaneously for the whole world.

sp332 14y ago
> does it really matter how it's implemented in this game? Yes, I imagine it would affect gameplay quite a bit.
- egypturnash 14y ago
  The various visual effects seem to be render-time transforms, so I suspect the speed change is propagating instantly across the gameworld. Can you think of a way to model a non-instantaneous propagation of this change that doesn't involve simulating oodles of photons wandering around the world?
  - Groxx 14y ago
    Yes. Light from source A travels at the speed determined by the last speed-wavefront that passed it. This can be modeled by storing the speed on the sources, or by calculating from all gathered orbs in the world, and selecting the most-recent, when the time is calculated by (<time picked up> at <distance when picked up> at <speed of light before picked up>). All such waves will be entirely contained within the previous wave because you cannot go faster than light and the speed only decreases, so all that matters is the speed before it was picked up, which is the speed the wave-front moves at (or does it move at the new speed? eh, pick either one, it doesn't matter.) Then, for each orb picked up since the most-recent that affected the source, the time for the light to reach the observer is based on <distance to orb N> at speed <before orb N> until <distance to orb N-1>. Then repeat for orb N-1 until you run out of orbs. In this case, N would be the oldest orb whose wavefront has not yet passed the source. It's a piece-wise calculation (the reverse of what's described), so it would be slower than instantaneous changes, but there's no need to model photons. And I would guess there's a reasonably-efficient way to calculate this on a GPU, so it could probably be real-time. Or it will be in a year or two.

m_darkTemplar 14y ago

It's instantaneous. There's no answer in physics for what should happen when you change the speed of light because that simply just can't happen. Therefore we didn't bother doing something like prorogation at the speed of light. We don't do gravity calculations, along with a few other things because we didn't have time and they make the other effects hard to see. In the future I would have liked to continue with the project and implement some of this though.

astrobe_ 14y ago
Cannot happen? Would we able to detect it if it actually did happen?