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Comment: Re: WTF? (Score 1) 48

by beelsebob (#48674289) Attached to: How Target's Mobile App Uses Location Tech To Track You

1) Following the maze around is trivially easy, and takes 5 minutes at most
2) They provide you with a map, and the locations of shortcuts, which are also trivially easy to find.

Something tells me you're the kind of person who can't manage to follow IKEA's simple instructions to assemble lego^Wfurniture either.

Comment: Re:Bogus algorithm (Score 3, Insightful) 33

by beelsebob (#48673963) Attached to: The World of YouTube Bubble Sort Algorithm Dancing

It's usually mentioned in CS courses because the first stage in introducing these classes is "think about sorting some numbers - how do you go about doing it", and generally Bubble Sort is the first formalisation that falls out of that. The fact that Selection Sort is the one that you think of is neither here nor there - most students come up with something looking like bubble sort.

Comment: Re:I RTFA'd, and I still want to know... (Score 1) 168

by beelsebob (#48669619) Attached to: Human Eye's Oscillation Rate Determines Smooth Frame Rate

Not quite. What gsync/freesync do is allow the monitor to be notified of when a frame has been produced, and trigger a swap exactly then. That doesn't mean that all frames are displayed for an equal amount of time.

Sure, it means that if one frame is late, it doesn't wait until the next vertical blank, but it does still mean that the previous frame is on screen for longer. If for example, a series of frames takes 12,14,30, and 16 ms to render, normally you'll see the frame before first for 16ms, the next for 16, the next for 33, the next for 16, etc. With gsync, you'll see them for 12ms, 14ms, 30ms and 16ms respectively. That's still jittery, just not as jittery.

Comment: Re:I RTFA'd, and I still want to know... (Score 2) 168

by beelsebob (#48667383) Attached to: Human Eye's Oscillation Rate Determines Smooth Frame Rate

Simple - game frame rates aren't consistent.

The effect of showing some frames for 16ms and others for 33ms (what will happen if your game is running at somewhere between 30 and 60 fps) is much more jarring to you than the effect of showing all frames for 42ms.

This is why hitting 60fps (or slightly above) is the magic number at which it all looks smooth again - at that point, all frames are rendered before the screen refreshes, and you get an absolutely smooth 60fps with 16ms frame times across the board. The reason you ideally want to be slightly above 60fps, is because some frames will always takes slightly longer to render than others, you want even those to be rendered before the screen refresh.

Comment: Re:It's in the image (Score 2) 168

by beelsebob (#48667363) Attached to: Human Eye's Oscillation Rate Determines Smooth Frame Rate

Suggest a technique for doing it then.

Hint: there are bad solutions to this, like blending with the previous frame, and there are really really expensive solutions to this, like figuring out the paths things moved over during the frame, and rendering along those paths.

Aside - games have a much bigger problem than motion blur. Movies run at a consistent 24fps, no matter what. Games meanwhile takes varying amounts of CPU and GPU time per frame, and have fixed time windows in which a frame must have been prepared. If that fixed time window is missed, the same frame gets presented twice (or at frame rates like 24fps 3-4 times), the effect of showing some frames form 16ms others for 33ms, still more for 50ms, and still more for 66ms is much more jarring than the effect of consistently showing all frames for 42ms.

Comment: Re:Old news. (Score 1) 281

by beelsebob (#48667307) Attached to: Study: Red Light Cameras Don't Improve Safety

No, 2 seconds is not going to be an "eventful" stop from 35mph. 0.8 seconds is an "eventful" stop from 35mph. You could stop in less than half the distance to the lights in that time.

What you're attempting to assert is that it's impossible to stop safely for a red light when you get an orange. This is clearly false, millions of people do it successfully every day.

Comment: Re: not original (Score 1) 183

by beelsebob (#48656953) Attached to: Uber Pushing For Patent On Surge Pricing

Prior art (what you are seeking) is only one way for a patent to be ruled invalid. Being obvious (anyone would have thought of pricing for supply and demand as the most idiotically simple thing you could do) is another.

Though, since you want prior art, it's well known that supermarkets dynamically adjust the price of different items in different shops based on the demand at that time and location.

Comment: Re:Old news. (Score 1) 281

by beelsebob (#48649691) Attached to: Study: Red Light Cameras Don't Improve Safety

At 30 mph your braking time (the time between slamming the brakes on and you stopping) is 1.8 seconds. Reaction time varies, but depending on circumstances it usually is between half a second and a second.

At 55 we're already at well over 2.5s for braking alone, without reaction time.

Don't just pull numbers out of your ass.

1) The amount of energy at 55mph is roughly 5 times higher than at 30mph, given that brakes dissipate a fairly constant amount of energy at all speeds, that means your braking time at 55 is 5 times that at 30.
2) Thankfully, that doesn't mean your braking time at 55 is 9 seconds for an emergency stop. That's because your figure for 30mph is bullshit. The actual braking time for an emergency stop from 30mph is 0.8 seconds, and at 55, roughly 4 seconds.

All this put together means that when you're presented with a 4 second orange at 30mph, and you have to do an emergency stop, that basically means you fucked around for 2.8 seconds. That is, the 4 seconds is made up of 0.5 seconds of reaction time, 2.8 seconds of fucking around doing nothing at all, and then 0.8 seconds of actually stopping. As I said before - if you're failing to stop for a red when given a warning with an orange, you're driving dangerously.

Note, this can be observed in every day life. It's trivial to test, you approach some lights at the speed limit. When they turn orange, you start to gently brake for the lights. Observe that you come to a stop before the lights even turn red.

Comment: Re:Old news. (Score 1) 281

by beelsebob (#48649671) Attached to: Study: Red Light Cameras Don't Improve Safety

If you spend 3 seconds not looking in front of you in a car, you're driving dangerously to start with. Count out 3 seconds in your head, and consider closing your eyes for that long while driving - you'll realise it's a really long time. In reality, people glance away at instruments/mirrors for 100ms at a time, not 3 seconds at a time.

Comment: Re:convex lens (Score 2) 114

by beelsebob (#48649619) Attached to: Finland Announces an Anti-Laser Campaign For Air Traffic

Are you suggesting that we simply list the professions that are allowed to have a genuine focused laser? If so, what happens when a spargeborgler (some new profession that critically relies on focused lasers) comes along? These laws always take years to get updated, leave horrible loop holes, and leave some people with genuine need out on the cold. If you can't express a general way to separate the groups, and have to revert to listing specifics, you're probably doing it wrong.

Computers are useless. They can only give you answers. -- Pablo Picasso

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