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Petey21
Account closed
Registered: Nov 2003
Posts: 49 |
Opening up borders
Here's a video (!) I found of a routine to open up the borders on a C64. No sound though, which would've been useful. Any comments on the code?
http://www.youtube.com/watch?v=Kh7xX1u3EME&NR |
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Oswald
Registered: Apr 2002
Posts: 5076 |
HCL, hehe, well actually I have never opened the sideborders, except of a weak try which was a flickering one line opening. but that was when I had no idea of stable rasters, I didnt even knew why do rasters flicker :) |
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tlr
Registered: Sep 2003
Posts: 1762 |
Quote: HCL, hehe, well actually I have never opened the sideborders, except of a weak try which was a flickering one line opening. but that was when I had no idea of stable rasters, I didnt even knew why do rasters flicker :)
Actually most early sideborder code didn't use stable rasters.
With 8 sprites it can easily be made self-stablizing, assuming you allow a few wasted lines of flickering border.
People mostly used it for scrollers, so those lines were usually wastable.
An additional feature is that below the sideborder routine, you are on a stable cycle. |
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Danzig
Registered: Jun 2002
Posts: 434 |
that you also can have with a single line of fld
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Radiant
Registered: Sep 2004
Posts: 639 |
Quote: that you also can have with a single line of fld
FLD = Flexible Line Distance; delayed bad line, which doesn't affect timing.
Don't you mean FLI? |
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Danzig
Registered: Jun 2002
Posts: 434 |
no
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Oswald
Registered: Apr 2002
Posts: 5076 |
Anyone else who wanna look smart (mmmm or stupid?:) just post your stabilizing and opening tips here :) how about showing off your skills in a demo instead trying to look smart in something that everyone knows since 20 years ? :P |
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Radiant
Registered: Sep 2004
Posts: 639 |
Quote: no
I'd very much like to see code using one line of FLD to stabilize the raster, I can't see how it could be done. |
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Scout
Registered: Dec 2002
Posts: 1570 |
Quote: I'd very much like to see code using one line of FLD to stabilize the raster, I can't see how it could be done.
I guess what Danzig means that it is possible to stabilize the rasters and open the sideborders by delaying the badlines too (just like in FLD).
Downside (ofcourse) is that you can't show gfx/text @ that area. Only sprites.
---
8Bit Mayhem - The C64 Scenemusic Podcast
http://8bitmayhem.untergrund.net |
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Radiant
Registered: Sep 2004
Posts: 639 |
Scout: How could the raster become stable by delaying badlines? Since BA (and AEC) will only go low if there are sprites on the line there's no way to get it stable that way, and the only other solutions I can see is using a timer, double irq, light pen or half variance, and those have got nothing to do with FLD. |
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Radiant
Registered: Sep 2004
Posts: 639 |
Not trying to be a smartass, I just wanna know if I've missed something. :-) |
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