Scanlines on vector games?

[Ummon]

Last year, I saw a Tempest up close. Something that really caught my attention, and something I thought I remembered from childhood, was that there were lines displayed, just like a raster monitor. I thought they were sorta vertical, but now I'm not sure. However, watching a Starcade episode recently I saw the same thing - except for Black Widow (a horizontal display) they were vertical lines; for Tac Scan (vertical display) they were horiztonal. ??


http://starcade.tv/starcade/featuredshow-90.asp


(Incidenatlly, this doesn't seem to happen with B/W vector monitors, as my vectrex only shows what seem like scanlines with certain text, which would point to coding.)

[NickG]

It is just the shadow mask /aperture grille:  Vector games do not have scan-lines(see correction in CT's post  ).  Here is something to try with one of your raster monitors at home to understand what you are looking at:  look at one of your monitors very closely when it is off.  Do you see those lines? Those are of the aperture grille or the shadow mask.  They are vertical on a horizontally positioned monitor and thus horizontal when you turn it on it's side (vertical monitor)  This is the same thing you were picking out in those Donkey Kong photos in one of your other scan-line confusion threads.  *they are not the scan-lines.

It may be a wise idea for you to visit wikipedia to learn about monitor technology.  They have a lot of great info about this sort of thing complete with photographs, and you seem to be posting a lot of threads like this. 

Edit: this post was later edited for clarity* and a correction

[ChadTower]

Vector monitors do display scanlines if you have the screen/brightness turned up too high.  They aren't horizontal or retrace lines like a raster but they are still scanlines.  They just happen to be direct XY grid movement patterns since the guns are tracing shapes rather than scanning whole horizontal lines.

If you look at a vector monitor close up (and off) you'll see the exact same thing you see with a raster.  The CRT is the same.

[RayB]

Ummon, what you saw is related only to the color ones. Something related to the method they use to get different colors to show up. I noticed the same thing at a fellow collector's house who has a few vector machines (both B&W and color).

[RandyT]

It's also interesting to note that a hi-res PC screen is actually capable of a sharper color "vector" image than the original color vector screens.  It won't be as bright, due to the raster scanning method, but because of the finer pitch of the shadow mask in the modern display, it will actually be a higher resolution output.

RandyT

[Ummon]

It is just the shadow mask /aperture grille:  Vector games do not have scan-lines(see correction in CT's post  ).  Here is something to try with one of your raster monitors at home to understand what you are looking at:  look at one of your monitors very closely when it is off.  Do you see those lines? Those are of the aperture grille or the shadow mask.  They are vertical on a horizontally positioned monitor and thus horizontal when you turn it on it's side (vertical monitor)  This is the same thing you were picking out in those Donkey Kong photos in one of your other scan-line confusion threads.  *they are not the scan-lines.

But see, the others say no. And what I saw wasn't from looking close up. I was standing at regular distance in front of the CP of the cab. However, due to the starcade vids fidelity, you can only see them close up there. (As well, I do see scanlines on original displays. We'd have to sit down in front of some machines and talk about this.)

Vector monitors do display scanlines if you have the screen/brightness turned up too high.  They aren't horizontal or retrace lines like a raster but they are still scanlines.  They just happen to be direct XY grid movement patterns since the guns are tracing shapes rather than scanning whole horizontal lines.

Ah, I thought so.

Ummon, what you saw is related only to the color ones. Something related to the method they use to get different colors to show up. I noticed the same thing at a fellow collector's house who has a few vector machines (both B&W and color).

You know, the other night I remembered this was so, and then wondered if I remembered correctly.

It's also interesting to note that a hi-res PC screen is actually capable of a sharper color "vector" image than the original color vector screens.  It won't be as bright, due to the raster scanning method, but because of the finer pitch of the shadow mask in the modern display, it will actually be a higher resolution output.

RandyT

Yes, as I've been finding out in particular with the new AAE emulator. So, particularly as I've not seen the answer anywhere: WHY is a vector display so bright??  (Gimme as technical as you like.)

[NickG]

It is just the shadow mask /aperture grille:  Vector games do not have scan-lines(see correction in CT's post  ).  Here is something to try with one of your raster monitors at home to understand what you are looking at:  look at one of your monitors very closely when it is off.  Do you see those lines? Those are of the aperture grille or the shadow mask.  They are vertical on a horizontally positioned monitor and thus horizontal when you turn it on it's side (vertical monitor)  This is the same thing you were picking out in those Donkey Kong photos in one of your other scan-line confusion threads.  *they are not the scan-lines.

But see, the others say no. And what I saw wasn't from looking close up. I was standing at regular distance in front of the CP of the cab. However, due to the starcade vids fidelity, you can only see them close up there. (As well, I do see scanlines on original displays. We'd have to sit down in front of some machines and talk about this.)

I am not sure what you mean by "the others say no."  Please elaborate if you care to help me learn something, too.  I was just making sure that you understand that the uniformly spaced lines that span the entire vector monitor are not scan lines and that the normally visible vector lines really are just point to point behind the grille/mask.  It would be really nice if many of BYOAC could sit down in front of some machines together, but I'd rather be playing than talking,  .   I say that and yet I am on a forum.  "Talking"

Vector monitors do display scanlines if you have the screen/brightness turned up too high.  They aren't horizontal or retrace lines like a raster but they are still scanlines.  They just happen to be direct XY grid movement patterns since the guns are tracing shapes rather than scanning whole horizontal lines.

Okay, I previously thought they were just referred to as retrace lines when working with a vector monitor, but I am still learning, too.

[ChadTower]

Okay, I previously thought they were just referred to as retrace lines when working with a vector monitor, but I am still learning, too.

Retrace lines are on a raster... it's the diagonal movement from the end of a horizontal line to the beginning of the next horizontal line.  Normally the gun gets turned off during this reset so you don't see anything happen but if the screen/brightness is up too high then you will see them.  You will also see them if certain parts have gone bad or if your monitor is way out of adjustment.

[RandyT]

Yes, as I've been finding out in particular with the new AAE emulator. So, particularly as I've not seen the answer anywhere: WHY is a vector display so bright??  (Gimme as technical as you like.)

Vector displays are bright because the duty cycle for the beam drawing the graphics can be much higher than with a raster monitor.  The vector monitor literally draws the individual objects on the face of the CRT, so depending on how many objects there are, the amount of "on" time to "off" time can be greater than with a raster monitor.  Of course, this also tends to make the objects "shimmer" because the brightness is always changing and more on-screen objects means more flicker.  The phosphor on a vector CRT also tends to be of longer persistence (at least with the mono screens).

I tend to believe that a raster monitor with a very high refresh rate, and the output cranked, could actually approach the brightness of a true color vector monitor.  The mono ones will always be nearly impossible to duplicate.  They don't have shadow masks in them.

RandyT

[Ummon]

Okay, I previously thought they were just referred to as retrace lines when working with a vector monitor, but I am still learning, too.

Retrace lines are on a raster... it's the diagonal movement from the end of a horizontal line to the beginning of the next horizontal line.  Normally the gun gets turned off during this reset so you don't see anything happen but if the screen/brightness is up too high then you will see them.  You will also see them if certain parts have gone bad or if your monitor is way out of adjustment.

Oh, I didn't understand the first time. These are sorta squirly lines that emanate from the center. You can actually see these using the AAE emulator if you turn the line phosphorescence or something up high. So that's not what I mean. But I don't think what I'm talking about is what NickG said, either. (Nor exactly in the raster monitor thread mentioned that I posted a little while ago, though the mask lines are a visual element.) The lines in that case would be continual - each drawn vector would be permeated with little divisions - and they aren't in what I'm seeing. They're spaced more than that.

[protokatie]

Yes, as I've been finding out in particular with the new AAE emulator. So, particularly as I've not seen the answer anywhere: WHY is a vector display so bright??  (Gimme as technical as you like.)

Vector displays are bright because the duty cycle for the beam drawing the graphics can be much higher than with a raster monitor.  The vector monitor literally draws the individual objects on the face of the CRT, so depending on how many objects there are, the amount of "on" time to "off" time can be greater than with a raster monitor.  Of course, this also tends to make the objects "shimmer" because the brightness is always changing and more on-screen objects means more flicker.  The phosphor on a vector CRT also tends to be of longer persistence (at least with the mono screens).

I tend to believe that a raster monitor with a very high refresh rate, and the output cranked, could actually approach the brightness of a true color vector monitor.  The mono ones will always be nearly impossible to duplicate.  They don't have shadow masks in them.

RandyT

I prefer to call this the "oscilloscope" effect. Since an oscilloscope is essentially a vector monitor with long lasting phosphores... erm I mean, just like a vector monitor (Except with different control circuits to move the beam).

Your explanation is more in depth tho.

[Matthew Fisher]

Yes, as I've been finding out in particular with the new AAE emulator. So, particularly as I've not seen the answer anywhere: WHY is a vector display so bright??  (Gimme as technical as you like.)

Vector displays are bright because the duty cycle for the beam drawing the graphics can be much higher than with a raster monitor.  The vector monitor literally draws the individual objects on the face of the CRT, so depending on how many objects there are, the amount of "on" time to "off" time can be greater than with a raster monitor.  Of course, this also tends to make the objects "shimmer" because the brightness is always changing and more on-screen objects means more flicker.  The phosphor on a vector CRT also tends to be of longer persistence (at least with the mono screens).

I tend to believe that a raster monitor with a very high refresh rate, and the output cranked, could actually approach the brightness of a true color vector monitor.  The mono ones will always be nearly impossible to duplicate.  They don't have shadow masks in them.

RandyT

I hadn't thought about the duty cycle issue before, and that is undoubtedly a very large part of the equation, but I would like to add one more observation.  The brightness of the "vectors" on the raster monitor wouldn't be the big problem, in my view, it would be the contrast.  To me, much of the visual appeal of the vector monitor comes from the difference between the laser-like vectors and the blackness of the background.   And it is truly black, as no electron is hitting those phosphors.  In a raster, all of them are getting hit with every refresh, even if they are supposed to be black.  I would be surprised if you could ever get a raster bright enough while still maintaining anything close to true black in the background.  Just my two cents...

[RandyT]

I hadn't thought about the duty cycle issue before, and that is undoubtedly a very large part of the equation, but I would like to add one more observation.  The brightness of the "vectors" on the raster monitor wouldn't be the big problem, in my view, it would be the contrast.  To me, much of the visual appeal of the vector monitor comes from the difference between the laser-like vectors and the blackness of the background.   And it is truly black, as no electron is hitting those phosphors.  In a raster, all of them are getting hit with every refresh, even if they are supposed to be black.  I would be surprised if you could ever get a raster bright enough while still maintaining anything close to true black in the background.  Just my two cents...

While I fully agree with you regarding the contrast being another difference, I don't necessarily believe that high contrast and high brightness need to be mutually exclusive on a raster screen.  And IIRC, some of those old color vector monitors used a gray phosphor, which meant a tinted window or exterior light control was a real necessity to give you that dark screen.

But considering where we are in the current state of technology, a raster CRT discussion is kind of moot anyway.  High resolution LCD panels (for now) are going to be the thing that gets the closest for a couple of reasons.  The first is that the LCD pixel just turns on and stays on until told to turn off.  This is, in essence, a 100% duty cycle.  Second, contrast ratios and brightness can be, and usually are, very high on LCD screens.  While the blacks aren't as intense on an LCD, the brightness and contrast levels open up the possibilities of using optical filters, like tinted glass / plexi, to tweak the output in order to get those dark blacks, as well as very acceptable brightness.  As the black level specifications get better, either through technology advancements in LCDs or totally new technologies, I think we'll see displays that, with the proper software to simulate the phosphor trails and flicker, can approach or even surpass what the color vector monitors can deliver.

RandyT

[Ummon]

  As the black level specifications get better, either through technology advancements in LCDs or totally new technologies, I think we'll see displays that, with the proper software to simulate the phosphor trails and flicker, can approach or even surpass what the color vector monitors can deliver.

RandyT

I suspect so, too. Same for native-like display on raster games, 15khz glow and all. However, until then, it's a matter of how determined one is.