If anyone is interested further in how vector effects were achieved, there is a good video showing the rendering of frames of Tempest in slow motion [0].
And if you're really interested in how vector effects were achieved, here's another that goes into the nitty gritty of how Tempest encoded point, line, color, etc. data in RAM and then rendered those images [1].
For the unaware, this quadrascan drew vector graphics by aiming the electron gun only where lines needed to be.
This meant most of the screen wasn't illuminated most of the time (think LCD vs OLED). This is why long exposures like this are possible and super interesting.
Are you sure? I see scan lines (of the NTSC/PAL variety) when I zoom in. I also don’t see how this scheme would be less possible with NTSC/PAL.
That’s disappointing, but understandable. It would need to be original cabinet hardware to be THAT cool.
EDIT: Ah, duh, in order to produce color it necessitates differently colored phosphors and a shadow mask, which might explain what I'm seeing. It does look like horizontal vector scan lines though, if you look at the screenshot I provided in other comments
> I see scan lines (of the NTSC/PAL variety) when I zoom in.
Color vector monitors still have discrete phosphors. You're not seeing discrete scanlines, you're seeing discrete lines of phosphors.
> I also don’t see how this scheme would be less possible with NTSC/PAL.
Vector drawn video games must necessarily be on an all black background. Video games that draw backgrounds and sprites typically illuminate the entire screen. Your character will move around on a colored background. It wouldn't make any sense to do a long exposure on an illuminated background; it would just be a picture of the background with some blurriness where the sprites occasionally were.
> Are you sure? I see scan lines (of the NTSC/PAL variety) when I zoom in.
The electron gun is still having to hit discrete pixels on the screen. Rather than drawing the image line by line, it's traveling at angles to render the image. It wasn't so much that these graphics couldn't be done with the NTSC/PAL standard (although you would have an increased backlight), but it was a limitation of game hardware of the time. Defining a series of points to draw lines between required less memory than sprite-based graphics.
Everyone's linking me to the vector graphics data but I know- Gen X here- I know that actual vector hardware would draw the actual lines and not leave horizontal scan lines visible. This looks like a photo of an emulator. See?
I know what that is. The scan lines I see are horizontal. An actual vector monitor would NOT leave horizontal scan lines as it would ACTUALLY be drawing the ACTUAL image (and not a rasterized version of it)
I'm not sure why everyone's jumping to (unnecessarily) correct me instead of actually zooming in on, say, the 2nd photo to see what I'm referring to. Here, let me try to screenshot:
Do you not see the horizontal scan lines here? A vector monitor has free reign over the beam's direction and would then not need to rasterize
EDIT: Ah, duh, in order to produce color it necessitates differently colored phosphors and a shadow mask, which might explain what I'm seeing. I was presuming single color vector display and no shadow mask, which is of course incongruous with the fact that Tempest is full-color.
What you're seeing are not 'scan lines'. This pattern is typical for a color vector monitor and is visible on real hardware (source: I own a Tempest arcade machine).
On a monochrome vector monitor, like an oscilloscope or Asteroids, there is one electron beam that draws on the single-phosphor screen, without obstructions between the beam and the screen, leaving sharp lines. There are no pixels as such (though the hardware in arcade games may be limited to moving the beam to discrete locations), the glass is just covered with a smooth layer of phosphor.
On a color vector monitor however there are three beams, and the screen has an RGB pattern of color sub-pixels. In between the electron guns and the screen is a 'shadow mask'. This is basically a plate with holes, positioned such that the 'blue' beam can only hit the blue subpixels, and likewise for the other colors.
What you see in the pictures is the result of the beams sweeping over that mask and interacting with the small dots of colored phosphor on the glass.
The CRT of a color vector game is just a standard television CRT. The electronics are very different however.
I'm lucky enough that our local Bar-cade has a legit Atari Asteroids machine, including an actual vector monitor. Nobody ever tells you about how BRIGHT the phosphors are! Every time you fire your weapon, you are bathed in light from a tiny little dot on screen. It's a unique experience in our day of LED displays.
A little off topic, but I recently bought an OM System OM-5 camera which can do similar - it can simulate an ND filter (up to 4 stops, the OM-1 can do up to 6) in camera, I guess with some continuous reading of the electronic shutter trickery, and combined with the really good IBIS (stabilisation to prevent camera shake), you can easily do handheld exposures of 1 second plus in daylight. Really fun effect for street photography if you want to capture people in motion. It can also just capture the maximum brightness of each pixel over the exposure, for easy light trails.
For me being able to do this kind of stuff without needing a tripod or external features was a big selling point of the camera.
There’s an iPhone app called Spectre (from the makers of Halide) which can do long exposures like this too, but I’ve not had the best luck with the results in comparison
I've got the OM-D E-M1 (from back when it was Olympus). The trick with their algorithm is that it's not simply adding to the frame. It's diffing, and adding whatever's left over. Which, as you note, does great for things like waterfalls.
If you've got any interest in astrophotography, I think you might be interested in this [1]. The combination of IBIS with the synthetic high-res mode inherently averages out noise in night sky shots, giving you both higher-resolution and very low noise.
The Tempest machine at college was lucky to get 10 quarters a week. We had a little cabal of players, one would put the morning quarter it, get the right score, fire up the free 40 credits, and that would be all she wrote. We'd play it throughout the day.
For the unaware, the early Tempest machine left the factory with several cheat codes that were enabled when you got specific scores in the game. One of those scores granted 40 free credits on the game. How these code left the factory is a mystery to me. The fellow who operated the arcade machines at the Student Union was obviously frustrated, as one week he showed up and cranked all of the difficulty settings as high as they would go, perhaps hoping that would boost the revenues.
It was so interesting early on because it was not uncommon to just walk into an arcade and find a Tempest machine with the free credits. But, eventually, someone figured out how it worked, and the word got out.
The real sleeper of a code was the code that unlocked all of the levels. Like many games, Tempest would allow you to continue near where you left off if you continued playing. After the game, it would go into attract mode. If it went a full cycle of the attract mode, it would reset. This is why the level unlock code remained elusive for so long, as you had let the machine fully cycle in order to enable it (which nobody normally wanted to do).
When that code got out, the high score on every machine in town skyrocketed since the game could be started at the highest level (level 81, the Green level I think).
Outside the cheat codes, it was a fabulously satisfying game, from the gameplay to the sounds, to the pace. There was real nice hit when you hit the Super Zapper (which killed all the monsters), cleared the level, immediately started rushing through, while holding down the fire button to grind down the remains of the spike in your lane before you got thrown into space. The sights and sounds of that was just great.
It was common practice in early Atari games to have custom, non-ASCII character sets. For Tempest, as an anti-tamper measure the team made the character assignments for the game's copyright message executable 6502 code. Periodically, in an obfuscated way, the machine would execute this code. People who pirated the ROM (this did happen in the industry) would be tempted to modify the message; the machine would crash, and they'd have to figure it out.
When the team (well, Dave Theurer) finished the game, they sent it off to the factory floor and went on vacation. Mission accomplished.
Then Atari legal decided that they had to update the copyright message (e.g., to alter some spelling). Since the team was away, someone without the above knowledge just changed the string. The game appeared to work, and that's what they shipped.
That modification didn't abjectly crash the machine. Instead, it did Weird Shit depending on the remainder of the score line.
Do you know of an analysis that details this? The post-mortem on this must have been crazy. That's got to be a great "You've got to be kidding me" moment for the folks when they went in to fix the issue.
Goes into excruciating detail of many of the anti-piracy measures in Tempest, and probably covers what the parent is talking about. All "writing" was executable code in Tempest because everything being drawn is by telling the electron gun where to aim, so you have commands like a "Turtle" graphics library.
There were sections of anti-piracy code that would check magic numbers and perturb those copyright drawing routines if the check failed.
I was about to nitpick that, then realised one can fake long exposure with a sequence of pictures.
The author mentioned car lights doing light painting, which is achieved by compositing at least two pictures (one long expo for lights, one for the car which would otherwise be blurry as well)
And if you're really interested in how vector effects were achieved, here's another that goes into the nitty gritty of how Tempest encoded point, line, color, etc. data in RAM and then rendered those images [1].
[0] https://www.youtube.com/watch?v=eJVpYL44jUQ
[1] https://www.youtube.com/watch?v=smStEPSRKBs