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[Cospefogo]

Screen tearing
From Wikipedia, the free encyclopedia

Screen tearing is a phenomenon in video where a previously rendered frame overlaps a newly rendered frame, creating a torn look as two parts of an object - for example a wall - don't line up. Screen tearing is most common with video games, as heavy processing can limit synchronization capabilities, although it can occur on all display types. Screen tearing happens when the display buffer is updated with a new image while the image is being transmitted to the display.

The use of vertical synchronization (V-sync) prevents screen tearing. V-sync is a method in which the display buffer is only updated during the vertical blanking interval.

Source: http://en.wikipedia....ki/Page_tearing


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Vertical synchronization
From Wikipedia, the free encyclopedia

Vertical synchronization (v-sync, vbl-sync) refers generally to the synchronization of frame changes with the vertical blanking interval. Since CRTs were nearly the only common video display technology prior to the widespread adoption of LCDs, the frame buffers in computer graphics hardware are designed to match the CRT characteristic of drawing images from the top down a line at a time by replacing the data of the previous frame in the buffer with that of the next frame in a similar fashion. If the frame buffer is updated with a new image while the image is being transmitted to the display, the frame buffer gives it the current mishmash of both frames, producing a page tearing artifact partway down the image.

Vertical synchronization eliminates this by timing frame buffer fills to coincide with the vertical blanking interval, thus ensuring that only whole frames are seen on-screen.

Computer games often allow vertical synchronization as an option, because it delays the image update until the vertical blanking interval, causing latency (the period of the refresh rate at maximum), which might be undesirable in games that require fast response (e.g. first person shooters).

VSYNC is also the name of the signal indicating this frame change in analogue RGB component video.

Source: http://en.wikipedia....synchronization


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Why do I get lots of screen tearing when I play certain games?

Many games do not have the exact same screen refresh rate as your monitor. Hence, there can be some dropped (or doubled) frames as the emulator tries to compensate.

Another problem is that the screen updating is not locked to the screen refresh rate. Therefore, the screen may be refreshed when only half of it has been updated. In these cases, this causes the top part of the screen be new, and the bottom part is from the previous frame. This is especially noticeable in horizontally scrolling games.

To fix this, use the -triplebuffer parameter, and set the native refresh rate of your monitor higher than that of the game you are running. Triple buffering updates the screen at exactly the screen refresh intervals to avoid tearing. However, since the monitor refresh rate can still be different from the emulation screen refresh rate, the games can still exhibit choppiness.

Source:
http://mamedev.org/d...x.php/FAQ:Video


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I'm not crazy! Other guy noticed screen tearing in Platinum V2:
http://www.1emulatio...php/t21577.html


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Screen tearing in MAMEoX CoinOPS
Game - Green Beret

There is a visible occurrence of screen tearing in the second floor
ladder in the first picture. I mean, it is not only in the ladder, it is
a horizontal problem that affects all screen. Just use the ladder
as reference.



The next picture show a yellow rectangle marking the area where
the problem occurs.



Please note that - when you walk and the screen moves, the "tearing"
moves together, from bottom to top, or from top to bottom, bringing
a very annoying effect, where one of the parts does not align with the other part.



And in the next picture a clear occurrence of tearing, in a closer view.



And this is a normal view, with NO TEARING.
I mocked up it on photoshop so you guys can see the
difference between both.



And that's it.
 

On CoinOPS:
Bad Dudes Vs Dragon Ninja, Green Beret (has few tearing, but it is there), Sly Spy,
Double Dragon, Robocop and others have this problem.

Regards,
Cospefogo.

[competes2win]

Thanks, Cool, Now I know.

[ressurectionx]

That's a great write up man.  Thanks for explaining it.  Now that you mention it, I have on occasion noticed this.  I didn't know it had a name or that it was even a fixable thing.  I probably just dismissed it as one of those weird glitches that you have to deal with when porting these things.

Great catch, I'm glad you lobbied hard for it and it's great that BP fixed that for us in the new release.

~Rx

[manu_xl]

BP is a credit whore. always making some minor gui changes based on other people's work. i talked once with the guy on IRC, he is lunatic without a real life.

kudos to the original mameox devs incl. the 128 devs. that were real devs!