[stella] Interlacing Success!

Subject: [stella] Interlacing Success!
From: "Billy Eno" <ceno@xxxxxxxxxxxxx>
Date: Fri, 16 Aug 2002 00:11:35 -0500
I believe I have gotten the 2600 to produce an interlaced display.  I need
some other folks out there to check it over for me, SuperCharger or
CuttleCart required, of course.  It does not seem to reduce the flickering
much for my playfield, but it sure does produce pretty lines.

The key seems to be starting the vertical sync half way through a scan line
and ending it halfway through a scanline, no messing with RSYNC required.
I am posting two .bin's, one interlaced, one non-interlaced.  Also a zip of
my messy code.  Main file is "cubeconq.s"  comment out line 157 to get the
non-interlaced version.

What you will see is the graphics registers drawing diagonal lines and a
different playfield in each frame.  The colors are the same in each frame to
more easily tell that the scan lines are indeed offset from one another.

I think If I judiciously chose backgrounds for each interlaced frame I could
reduce the effect of the flickering, though I am guessing that is the same
thing you would do for non-interlaced too.

By the way, if for some reason I am fooling myself completely, feel free to
tell me, I certainly won't be insulted! :>


Attachment: cubeinterlace.zip
Description: Zip compressed data

Attachment: cube_noninterlaced.bin
Description: Binary data

Attachment: cube_interlaced.bin
Description: Binary data

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