What was the output resolution for Tempest?

disjaukifa

New member
Joined
Nov 9, 2011
Messages
2,837
Reaction score
31
Location
Ridgeway, Virginia
Hey Guys,

I know this is a really random question, but what is the output for Tempest? I know the b&w Atari games are 1024x768, but what are the color vectors? I read somewhere that they were a lower resolution.

Thanks
 
The b&w ones aren't exactly 1024x768. They endpoints of the line segments are on a 1024x768 grid, but the interior of the segments are interpolated with analog hardware.
 
The b&w ones aren't exactly 1024x768. They endpoints of the line segments are on a 1024x768 grid, but the interior of the segments are interpolated with analog hardware.

Mostly. The DACs that generate the analog signal are 10 bit, so 1024x1024 is the closest thing to a native resolution. This is abstracted from the game code somewhat, so I don't know what view of things that stuff has.

But you're right that things are interpolated, I think, and the concept of raster resolution is not applicable.
 
I think G08 (sega's color vector) is also like 1024x768 if i remember right... The G08 or Sega XY FAQ mentions it

I think the original poster knows the difference between raster and vector, and the question made sense to me
 
I think G08 (sega's color vector) is also like 1024x768 if i remember right... The G08 or Sega XY FAQ mentions it

I think the original poster knows the difference between raster and vector, and the question made sense to me

Boy it doesn't look like 1024x768...

A B&W vector like Asteroids looks like it has vastly more resolution than my Star Trek... I could believe it had 1024x1024 or 1024x768 resolution...

For decades I've been wondering what the resolution really was for these vector games. They just absolutely blew me away when I saw them for the first time in an arcade.
 
Last edited:
Boy it doesn't look like 1024x768...

A B&W vector like Asteroids looks like it has vastly more resolution than my Star Trek... I could believe it had 1024x1024 or 1024x768 resolution...

For decades I've been wondering what the resolution really was for these vector games. They just absolutely blew me away when I saw them for the first time in an arcade.

You definitely pay a price for color. The shadow mask to separate red, green, and blue makes it look far lower resolution.
 
Screen Coordinate System:

The screen position is represented by a pair of 11 bit values (two bytes
each) in each symbol structure.

The screen itself can be thought of as this:

2048
|
|
|
|
|
+------------ 2048
0,0

That is, the origin is in the lower left hand corner and coordinates move
up and right.

The center of the screen is 0x400,0x400.

A hardware clipping circuit clips the screen to a subset of this amount:

1536
+-------------------+
| |
| |
| |
512| 1024,1024 |1536
| |
| |
| |
+-------------------+
512

The center is at 1024,1024.

The display "clips" at the same values on the x and y axis, so since the
display isn't exactly square there must be a little distortion. (a square
should be slightly wider than tall on the screen)

Hardware Scaling:

Scaling is simple binary scaling with a single byte value.
0x80 appears to be 1:1, 0xFF is 2:1
0x40 is 1:2, 0x20 is 1:4, 0x10 is 1:8 etc...
This means that there's more "dynamic range" in the bottom end of the
scaling, so things should look nicer if drawn large and scaled down.

from
http://arcarc.xmission.com/Tech/Monitor Misc/Sega G80 Vector Hardware Reference.txt

must be what i remembered reading, so i was off by over 2x...

besides the endpoint coordinate system, there can be other things that affect what the resolution "looks like" to a user used to raster displays... the dot pitch of the mask/screen is probably the most obvious, and is one of the reasons an Amplifone is desireable... basically it has the tube of a medium res monitor, so a finer pitch

so when those analog lines are drawn they span more rows/columns of phosphor creating less jaggeds(aliasing)
 
So if I'm interpreting that right, there are about 1024x1024 usable pixels?
 
The Atari vector generators, both digital and analog, are discussed at length by one of their creators, Jed Margolin, here (bottom of page linked, scoll up to read details): http://www.jmargolin.com/vgens/vgens.htm#A Final

As others have mentioned, the concept of resolution makes perfect sense in a raster game/monitor, but isn't directly applicable to a vector monitor/game. There are a finite number of start/end positions, but the lines between (in an analog VG) are essentially straight lines, not "pixel" representations of them.

From the above linked page:

1. The Digital Vector Generator produces vectors consisting of points at discrete coordinates. While the Analog Vector Generator has discrete values representing the length of a vector, the values in-between are continuously and infinitesimally changed (subject to the restrictions of living in a Quantum Universe). Thus, there is no stairstepping.
 
The Atari vector generators, both digital and analog, are discussed at length by one of their creators, Jed Margolin, here (bottom of page linked, scoll up to read details): http://www.jmargolin.com/vgens/vgens.htm#A Final

As others have mentioned, the concept of resolution makes perfect sense in a raster game/monitor, but isn't directly applicable to a vector monitor/game. There are a finite number of start/end positions, but the lines between (in an analog VG) are essentially straight lines, not "pixel" representations of them.

From the above linked page:

What an incredibly cool link you posted there, Darren. The last third of the document makes for a very interesting read even for the non-hw tech geeks.
 
I have seen a thread here where a member swapped a raster monitor tube into a vector monitor chassis either by swapping the yoke from the vector tube on to the raster tube or by rewrapping the raster tube's yoke to make it compatible with a vector chassis.

With all this talk about dot pitch of the screen, I was wondering if anyone used a VGA tube with it's higher resolution shadow mask to get a crisper image? Granted you wouldn't get a higher resolution image, but it would look better I think.
 
Technically its not std vs med res... I think the Mxxxxxxxx tube has a finer pitch then the Axxxxxxxxx tubes. Interestingly I see the same tube on std res & med res monitors. I may be wrong on the M vs A designation.
 
I recall seeing a Tempest in the wild just a few years ago.

I was amazed, but then I started staring and looking real close, getting picky about the grainy looking lines.

I had gotten used to playing Tempest in MAME on a nice, small dot-pitch computer monitor.

Big difference. You can make up for it some by cranking the brightness a little. All the vivid colors make up for the low res.

It probably would look really nice on a computer CRT.

Kerry
 
Back
Top Bottom