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Why does the original Donkey Kong update the screen in a curtain closing patern?
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For those of you who don't know, Billy Mitchell, the former Donkey Kong world record champion was caught cheating due to differences between the original Donkey Kong format, and MAME. In other words, he had been using an emulator to fabricate his scores. Whether or not this is the case is not an issue to be discussed on StackExchange, however, I would like to ask why the Donkey Kong transition screen is so atypical.
Here here is an image of what I mean:
https://i.imgur.com/0cYAQjt.gif
Notice how the screen loads kind of like a curtain closing animation. This is not a part of the game's code, and is not present in M.A.M.E.. What causes this?
nintendo arcade mame
asked 2 hours ago
Jack Kasbrack
713426
add a comment |Â
up vote
2
down vote
favorite
For those of you who don't know, Billy Mitchell, the former Donkey Kong world record champion was caught cheating due to differences between the original Donkey Kong format, and MAME. In other words, he had been using an emulator to fabricate his scores. Whether or not this is the case is not an issue to be discussed on StackExchange, however, I would like to ask why the Donkey Kong transition screen is so atypical.
Here here is an image of what I mean:
https://i.imgur.com/0cYAQjt.gif
Notice how the screen loads kind of like a curtain closing animation. This is not a part of the game's code, and is not present in M.A.M.E.. What causes this?
nintendo arcade mame
asked 2 hours ago
Jack Kasbrack
713426
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
For those of you who don't know, Billy Mitchell, the former Donkey Kong world record champion was caught cheating due to differences between the original Donkey Kong format, and MAME. In other words, he had been using an emulator to fabricate his scores. Whether or not this is the case is not an issue to be discussed on StackExchange, however, I would like to ask why the Donkey Kong transition screen is so atypical.
Here here is an image of what I mean:
https://i.imgur.com/0cYAQjt.gif
Notice how the screen loads kind of like a curtain closing animation. This is not a part of the game's code, and is not present in M.A.M.E.. What causes this?
nintendo arcade mame
asked 2 hours ago
Jack Kasbrack
713426
For those of you who don't know, Billy Mitchell, the former Donkey Kong world record champion was caught cheating due to differences between the original Donkey Kong format, and MAME. In other words, he had been using an emulator to fabricate his scores. Whether or not this is the case is not an issue to be discussed on StackExchange, however, I would like to ask why the Donkey Kong transition screen is so atypical.
Here here is an image of what I mean:
https://i.imgur.com/0cYAQjt.gif
Notice how the screen loads kind of like a curtain closing animation. This is not a part of the game's code, and is not present in M.A.M.E.. What causes this?
nintendo arcade mame
nintendo arcade mame
asked 2 hours ago
Jack Kasbrack
713426
asked 2 hours ago
Jack Kasbrack
713426
asked 2 hours ago
Jack Kasbrack
713426
asked 2 hours ago
Jack Kasbrack
713426
asked 2 hours ago
Jack Kasbrack
713426
713426
add a comment |Â
add a comment |Â
1 Answer
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This isn't a deliberate animation, it's an accident of the way the screen is being photographed, combined with the fact that a Donkey Kong arcade machine uses a CRT turned on its side.
A typical CRT draws an image by drawing many successive horizontal lines, starting at the top and working towards the bottom. The "refresh rate" indicates how many times this is done per second, so a 60Hz refresh means the screen is redrawn 60 times per second. A 60Hz refresh also means that it takes around 1/60th of 1 second to draw 1 "frame". During this 1/60th of a second, the electron beam needs to paint the entire screen top to bottom, then move back up to the top of the screen in time for the next frame.
In the Donkey Kong cabinet, the CRT is turned sideways so that instead of drawing frames from top to bottom, it's done side to side. When you take a picture of the screen, you might see that only a part of the screen is drawn; how much appears drawn depends on when precisely the picture was taken compared to where on-screen the electron beam happened to be. Cameras are typically fast enough to capture this, but the human eye won't notice.
So the 'curtain' effect is actually due to a slight timing mismatch between how fast the camera is capturing images of the screen, compared to the rate at which the screen is being redrawn. Sometimes the camera will capture the screen mid-frame, which is what you're seeing.
answered 2 hours ago
Ken Gober
6,9361837
So if the alleged cheat had just bothered to mount his CRT sideways, he might have gotten away with it?
– Tommy
39 mins ago
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
This isn't a deliberate animation, it's an accident of the way the screen is being photographed, combined with the fact that a Donkey Kong arcade machine uses a CRT turned on its side.
A typical CRT draws an image by drawing many successive horizontal lines, starting at the top and working towards the bottom. The "refresh rate" indicates how many times this is done per second, so a 60Hz refresh means the screen is redrawn 60 times per second. A 60Hz refresh also means that it takes around 1/60th of 1 second to draw 1 "frame". During this 1/60th of a second, the electron beam needs to paint the entire screen top to bottom, then move back up to the top of the screen in time for the next frame.
In the Donkey Kong cabinet, the CRT is turned sideways so that instead of drawing frames from top to bottom, it's done side to side. When you take a picture of the screen, you might see that only a part of the screen is drawn; how much appears drawn depends on when precisely the picture was taken compared to where on-screen the electron beam happened to be. Cameras are typically fast enough to capture this, but the human eye won't notice.
So the 'curtain' effect is actually due to a slight timing mismatch between how fast the camera is capturing images of the screen, compared to the rate at which the screen is being redrawn. Sometimes the camera will capture the screen mid-frame, which is what you're seeing.
answered 2 hours ago
Ken Gober
6,9361837
So if the alleged cheat had just bothered to mount his CRT sideways, he might have gotten away with it?
– Tommy
39 mins ago
add a comment |Â
up vote
4
down vote
This isn't a deliberate animation, it's an accident of the way the screen is being photographed, combined with the fact that a Donkey Kong arcade machine uses a CRT turned on its side.
A typical CRT draws an image by drawing many successive horizontal lines, starting at the top and working towards the bottom. The "refresh rate" indicates how many times this is done per second, so a 60Hz refresh means the screen is redrawn 60 times per second. A 60Hz refresh also means that it takes around 1/60th of 1 second to draw 1 "frame". During this 1/60th of a second, the electron beam needs to paint the entire screen top to bottom, then move back up to the top of the screen in time for the next frame.
In the Donkey Kong cabinet, the CRT is turned sideways so that instead of drawing frames from top to bottom, it's done side to side. When you take a picture of the screen, you might see that only a part of the screen is drawn; how much appears drawn depends on when precisely the picture was taken compared to where on-screen the electron beam happened to be. Cameras are typically fast enough to capture this, but the human eye won't notice.
So the 'curtain' effect is actually due to a slight timing mismatch between how fast the camera is capturing images of the screen, compared to the rate at which the screen is being redrawn. Sometimes the camera will capture the screen mid-frame, which is what you're seeing.
answered 2 hours ago
Ken Gober
6,9361837
So if the alleged cheat had just bothered to mount his CRT sideways, he might have gotten away with it?
– Tommy
39 mins ago
add a comment |Â
up vote
4
down vote
up vote
4
down vote
This isn't a deliberate animation, it's an accident of the way the screen is being photographed, combined with the fact that a Donkey Kong arcade machine uses a CRT turned on its side.
A typical CRT draws an image by drawing many successive horizontal lines, starting at the top and working towards the bottom. The "refresh rate" indicates how many times this is done per second, so a 60Hz refresh means the screen is redrawn 60 times per second. A 60Hz refresh also means that it takes around 1/60th of 1 second to draw 1 "frame". During this 1/60th of a second, the electron beam needs to paint the entire screen top to bottom, then move back up to the top of the screen in time for the next frame.
In the Donkey Kong cabinet, the CRT is turned sideways so that instead of drawing frames from top to bottom, it's done side to side. When you take a picture of the screen, you might see that only a part of the screen is drawn; how much appears drawn depends on when precisely the picture was taken compared to where on-screen the electron beam happened to be. Cameras are typically fast enough to capture this, but the human eye won't notice.
So the 'curtain' effect is actually due to a slight timing mismatch between how fast the camera is capturing images of the screen, compared to the rate at which the screen is being redrawn. Sometimes the camera will capture the screen mid-frame, which is what you're seeing.
answered 2 hours ago
Ken Gober
6,9361837
This isn't a deliberate animation, it's an accident of the way the screen is being photographed, combined with the fact that a Donkey Kong arcade machine uses a CRT turned on its side.
A typical CRT draws an image by drawing many successive horizontal lines, starting at the top and working towards the bottom. The "refresh rate" indicates how many times this is done per second, so a 60Hz refresh means the screen is redrawn 60 times per second. A 60Hz refresh also means that it takes around 1/60th of 1 second to draw 1 "frame". During this 1/60th of a second, the electron beam needs to paint the entire screen top to bottom, then move back up to the top of the screen in time for the next frame.
In the Donkey Kong cabinet, the CRT is turned sideways so that instead of drawing frames from top to bottom, it's done side to side. When you take a picture of the screen, you might see that only a part of the screen is drawn; how much appears drawn depends on when precisely the picture was taken compared to where on-screen the electron beam happened to be. Cameras are typically fast enough to capture this, but the human eye won't notice.
So the 'curtain' effect is actually due to a slight timing mismatch between how fast the camera is capturing images of the screen, compared to the rate at which the screen is being redrawn. Sometimes the camera will capture the screen mid-frame, which is what you're seeing.
answered 2 hours ago
Ken Gober
6,9361837
answered 2 hours ago
Ken Gober
6,9361837
answered 2 hours ago
Ken Gober
6,9361837
answered 2 hours ago
Ken Gober
6,9361837
6,9361837
So if the alleged cheat had just bothered to mount his CRT sideways, he might have gotten away with it?
– Tommy
39 mins ago
add a comment |Â
So if the alleged cheat had just bothered to mount his CRT sideways, he might have gotten away with it?
– Tommy
39 mins ago
So if the alleged cheat had just bothered to mount his CRT sideways, he might have gotten away with it?
– Tommy
39 mins ago
So if the alleged cheat had just bothered to mount his CRT sideways, he might have gotten away with it?
– Tommy
39 mins ago
add a comment |Â
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