[F9 CS3] Jaggies flickering when scrolling: Is this a Flash issue or just perception?

ignignokt · 12-04-2007, 04:16 AM

I'm scrolling a bitmap that has intentional jaggies in it. They're diagonal waves drawn with blocks that are 4x4 pixels each. They look like the hills from <a href="http://vgmaps.com/Atlas/NES/SuperMarioBros2-World1-Area1.png">here</a>, except four times as large. When I scroll them by at 8 pixels per frame, the areas that are heavy with jaggies look like they're flickering.

I was considering doing some form of double buffering with this, but when I think about it I doubt it'd help.

Any ideas on how to get them to not flicker?

I've tried increasing the frame rate, but that doesn't seem to matter.

Slowing the rate of scrolling drastically stops the flickering, but that's not an option.

iopred · 12-04-2007, 10:33 AM

I think what you're seeing is tearing. And it can't be fixed, there is no way to vsync Flash atm.

Ray Beez · 12-04-2007, 06:09 PM

That's an inherent optical effect from unsyncronized displays. Even with syncronization (Vsync iopred mentioned) you can still get the effect appearing based on the amount of scroll. For example on the TV console game systems, if you scrolled a level by multiples of 2 (ie, shift the screen by 1, 2, 4, 8 etc pixels) each screen refresh, the effect would look perfectly smooth. But if you used a value like 3, 5, 6, 7 etc it looked blurry/jerky.

Weird but true.

ignignokt · 12-04-2007, 06:51 PM

Thanks, guys. I suspected as much. At least I know I can give up on having the jaggies in the bitmap now.

12-04-2007, 04:16 AM	#1
ignignokt Junior Member Join Date: Dec 2007 Posts: 2	[F9 CS3] Jaggies flickering when scrolling: Is this a Flash issue or just perception? I'm scrolling a bitmap that has intentional jaggies in it. They're diagonal waves drawn with blocks that are 4x4 pixels each. They look like the hills from <a href="http://vgmaps.com/Atlas/NES/SuperMarioBros2-World1-Area1.png">here</a>, except four times as large. When I scroll them by at 8 pixels per frame, the areas that are heavy with jaggies look like they're flickering. I was considering doing some form of double buffering with this, but when I think about it I doubt it'd help. Any ideas on how to get them to not flicker? I've tried increasing the frame rate, but that doesn't seem to matter. Slowing the rate of scrolling drastically stops the flickering, but that's not an option.

12-04-2007, 10:33 AM	#2
iopred Heli Attack! Join Date: Jun 2003 Location: Sydney, Australia Posts: 923	I think what you're seeing is tearing. And it can't be fixed, there is no way to vsync Flash atm. __________________ Christopher Rhodes squarecircleco.

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12-04-2007, 06:09 PM	#3
Ray Beez Senior Member Join Date: Jun 2000 Posts: 2,692	That's an inherent optical effect from unsyncronized displays. Even with syncronization (Vsync iopred mentioned) you can still get the effect appearing based on the amount of scroll. For example on the TV console game systems, if you scrolled a level by multiples of 2 (ie, shift the screen by 1, 2, 4, 8 etc pixels) each screen refresh, the effect would look perfectly smooth. But if you used a value like 3, 5, 6, 7 etc it looked blurry/jerky. Weird but true.

12-04-2007, 06:51 PM	#4
ignignokt Junior Member Join Date: Dec 2007 Posts: 2	Thanks, guys. I suspected as much. At least I know I can give up on having the jaggies in the bitmap now.