Subject: RE: [stella] Higher Resolution through Interlacing From: Chris Wilkson <ecwilkso@xxxxxxx> Date: Thu, 15 Aug 2002 23:05:42 -0400 (EDT) |
Hi everyone! I'm in Missouri, without direct access. So I'll be unusually slow (sorry! sorry!) about reply to emails. This should only last a couple of weeks. -Chris On Wed, 14 Aug 2002, Billy Eno wrote: > Chris, > > This is from a month ago, I think I want to give it a shot. > > You say you hit the RSYNC half way through line 262. Then, you draw the > next interleaved frame, which is also 162 lines. You said you have to play > with VSYNC, how do you play with it, does it just need to be hit at the same > time as the RSYNC, to get the display to start over at the top? > > And, did you actually get this working on the 2600 at one point, or are you > talking about some other system? > > Billy > > > -----Original Message----- > > From: owner-stella@xxxxxxxxxxx [mailto:owner-stella@xxxxxxxxxxx]On > > Behalf Of Chris Wilkson > > Sent: Sunday, June 30, 2002 11:46 PM > > To: stella@xxxxxxxxxxx > > Subject: RE: [stella] Higher Resolution through Interlacing > > > > > > On Sun, 30 Jun 2002, Billy Eno wrote: > > > > > Interesting background on how TV's actually work. I certainly > > was unaware. > > > It would be pretty easy to write a demo to see if it worked (I > > think), and I > > > may try. But, if a TV interlaces two succesive Atari 2600 "frames" to > > > create an image, how would you (or the TV)know if the first frame was an > > > "odd" (to the TV) or an "even" (to the TV). If the you didn't > > start with > > > the correct frame, likely the graphics wouldn't look right. > > > > The 2 fields should properly look like this: > > > > ******************** xxxxxxxxxx > > ******************** xxxxxxxxxxxxxxxxxxxx > > ******************** xxxxxxxxxxxxxxxxxxxx > > ******************** xxxxxxxxxxxxxxxxxxxx > > ******************** xxxxxxxxxxxxxxxxxxxx > > ******************** xxxxxxxxxxxxxxxxxxxx > > ********** xxxxxxxxxxxxxxxxxxxx > > field 0 field 1 > > > > Notice that field 1 starts in midline, just where field 0 left off. And > > field 0 starts at the beginning of the line, where field 1 left off. > > If you draw these 2 fields sequentially, you see how the lines get > > interlaced. Remember that the lines are actually drawn diagonally, > > because the electron beam moves downward at a constant rate. It's hard > > to draw in text, but I'll try. Heres a display with 2.5 lines per field, > > or 5 lines per frame: (again, "*" represents field 0 and "x" represents > > field 1) > > > > > > * x > > * x > > * x > > x * > > x * > > x * > > * x > > * x > > * x > > x * > > x * > > x * > > * x > > * x > > * x > > > > -Chris > > > > ------------------------------------------------------------------ > > ---------------------------- > > Archives (includes files) at http://www.biglist.com/lists/stella/archives/ > > Unsub & more at http://www.biglist.com/lists/stella/ > > > > ---------------------------------------------------------------------------------------------- > Archives (includes files) at http://www.biglist.com/lists/stella/archives/ > Unsub & more at http://www.biglist.com/lists/stella/ > > ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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