Interlaced Graphics

BlitzPlus Forums/BlitzPlus Programming/Interlaced Graphics

Jay Mattis(Posted 2003) [#1]
Is it possible to draw interlaced graphics? Does anyone know how to draw one buffer on even scanlines and one on odd scanlines, or something to that effect?


WolRon(Posted 2003) [#2]
AFAIK, I've never heard of this being a feature of any video card. Cheap monitors and HDTV's can refresh the screen interlaced, but I don't know if this is a programmable feature.

I suppose you could write your own routine to update the backbuffer or an imagebuffer interlaced, but you would have to do tests to see how efficient it could be.


Pongo(Posted 2003) [#3]
Is there any particular reason why you would want to do this? I work in animation, and for video this is common practice due to the way televisions display fields, but why would you want to do this on a monitor? (Even if you did the fields properly, they would not look right unless displayed on a monitor using the interlacing)

Are you just going for a certain look of the scanlines?


Jay Mattis(Posted 2003) [#4]
It's not a feature of the video card or a monitor. It's all in how you rasterize it. I was just wondering if anyone had ever tried this. The reason I would like to display two different buffers interlaced on the screen is for a HMD (Head Mounted Display). If I can do that, stereoscopic display is very easy. Although it halves the resolution displayed, it's much more reliable than page flipping.


Pongo(Posted 2003) [#5]
Ahh,... I understand now,... sorry I can't help,... I just wanted to make sure you knew what you were asking for and were not just going for a certain look.

One thing you might be able to try, although it may be too slow,... is to draw the two seperate buffers,... then overly an interlace mask over the one layer and then copy it over to the second buffer using the mask. I'm sure this is probably too slow, but it's a thought.


Jay Mattis(Posted 2003) [#6]
That's actually a really good idea. I'll try that. Thanks.


Jay Mattis(Posted 2003) [#7]
Well, it's not that slow, but it also doesn't work. *sigh* I guess I'm stuck with page flipping.