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A Slower Speed of Light

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Re: A Slower Speed of Light

#61

Post by tzs »

flebron wrote: post #56
kzahel wrote: post #13

Once you get all 100 orbs and you get close to the speed of light you're in for a treat. It gets rid of the funny color saturation effects and you only see the Lorentz transformation. I'd like to know the secret incantations to be able to modify the speed of light manually. (Once you walk fast as light, the game abruptly ends)

I think if you don't go under the white arch, you can stay indefinitely in Lorentz transformations mode. At least, I stayed that way for several seconds if I avoided that arch.

ESC also seems to end it if you have 100 orbs, instead of taking you to the settings screen as I would have expected.

Also, be careful running with 100 orbs. I ran into a fence and got stuck on it.

Re: A Slower Speed of Light

#64

Post by Groxx »

egypturnash wrote: post #59
sp332 wrote: post #39

Earlier quoted context omitted.

> does it really matter how it's implemented in this game? Yes, I imagine it would affect gameplay quite a bit.

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?

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 ( at at ).

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 at speed until . 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.

Re: A Slower Speed of Light

#65

Post by jasonwatkinspdx »

StavrosK wrote: post #49
Evbn wrote: post #48

Earlier quoted context omitted.

Photons always travel at the speed of light in every frame of reference. Only the medium matters, not the observer's speed. The observable change is the separation between photons (wavelength) caused by a moving source.

Photons traveling along an X axis are traveling along a Y axis at 0 m/s. If you're traveling along the Y axis, you're going faster.

Except that's not what we measure. Instead we find the speed of a photon depends only on the medium, not on the motion of the source or receiver.

Re: A Slower Speed of Light

#66

Post by StavrosK »

jasonwatkinspdx wrote: post #65
StavrosK wrote: post #49

Earlier quoted context omitted.

Photons traveling along an X axis are traveling along a Y axis at 0 m/s. If you're traveling along the Y axis, you're going faster.

Except that's not what we measure. Instead we find the speed of a photon depends only on the medium, not on the motion of the source or receiver.

You aren't listening to me. The speed of the photon is c in the direction it's traveling, a photon traveling due west is going north with no speed at all.

Re: A Slower Speed of Light

#67

Post by peaigr »

SoftwareMaven wrote: post #51
undershirt wrote: post #32

I don't understand why the colors are changing. Shouldn't the doppler effect not apply if the speed of light is the same for all observers?

The Doppler effect is how Hubble determined the universe is expanding. All of the galaxies around us are shifted red.

Cosmological redshift comes from general relativity, not the SR Doppler effect. Local motion does produce a shift on top of that, but that's not all redshift. Nearby galaxies are actually blue shifted.

Re: A Slower Speed of Light

#68

Post by bluedanieru »

StavrosK wrote: post #16
bluedanieru wrote: post #9

I may be off-base here, but isn't the length contraction backward? Things should appear closer as you approach the speed of light, not farther away. And, it should not matter if you move backward or forward to observe that effect, yet it does (try moving backwards). Also, relativistic motion doesn't appear to affect the movements of the other actors, though it's kind of hard to tell for certain.

With my very limited understanding, my impression is this: As you move in relativistic speeds, your eye hits more photos, even those going sideways (or backwards), because the photons at an angle are slower than your eye (imagine a car moving fast through the rain, even drops that go in the other direction will hit your windshield). Therefore, your field of vision grows (you can see things behind you), but only when…

I think I got it. Lengths will contract, but when you're moving toward something very quickly, the speed of light remaining constant, it will seem farther away. And the reverse is true when you're moving away from it.

It actually helps to just forget about relativity for a moment, and think about the angles light from distant objects will have to take to intercept you. Then it becomes more clear.

Re: A Slower Speed of Light

#69

Post by StavrosK »

bluedanieru wrote: post #68
StavrosK wrote: post #16

Earlier quoted context omitted.

With my very limited understanding, my impression is this: As you move in relativistic speeds, your eye hits more photos, even those going sideways (or backwards), because the photons at an angle are slower than your eye (imagine a car moving fast through the rain, even drops that go in the other direction will hit your windshield). Therefore, your field of vision grows (you can see things behind you), but only when…

I think I got it. Lengths will contract, but when you're moving toward something very quickly, the speed of light remaining constant, it will seem farther away. And the reverse is true when you're moving away from it. It actually helps to just forget about relativity for a moment, and think about the angles light from distant objects will have to take to intercept you. Then it becomes more clear.

Yes, exactly. Your eye intercepts photons from a wider angle the faster you're moving, therefore you get a wider field of view, even seeing things behind you.

I'm not sure I'm missing a step going from "wider fov" to "things seem farther away", maybe I am...

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