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Doctor: A new demo by Trilobit for the Atari 2600


visyli

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Impressive! ... and a tad crazy...

 

If I ever truly (and completely) go insane, I think this is what I will see. ;)

That reminds me of that obscure 80's movie where the star was blind but had an electronic vision device plugged into his brain (based on sonar so he couldn't see a television.) He wanted to play a 2600, so he plugged it into the device, and he went on a massive head trip. I think it was this movie. But I digress - great demo.

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Do you have a Commodore 1702 monitor? Because If I adjust the V.Hold just right, I can play PAL games on it in color and with no rolling with an NTSC 2600.

Yes, I have some 1702s, although they are pretty small so I typically use 20" Sony TV. I have used them in the past to test PAL games. The colors are still wrong, though. :D

 

..Al

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Awesome! Reminds me slightly of this (one of my alltime favourite demos):

 

PWP Robotic Liberation (unexpanded Vic 20):

 

Regards,

Moderntimes99

That's pretty cool, didn't realize there were demos on the VIC! Looks like they were doing raster interrupts in it, but the VIC doesn't have raster interrupts... :ponder: Probably doing timer interrupts to simulate raster interrupts.

 

EDIT: Yep, VIC raster interrupts are simulated by using interrupts on 2 timers - Making stable raster routines (C64 and VIC-20)

On the VIC-20, there is no Raster interrupt feature in the video chip. All you can do is to use a timer for generating raster interrupts. And if you use two timers running at a constant phase difference, you can get full synchronization. The first timer generates the raster interrupt, and the second timer, the auxiliary timer, tells the raster routine where it is running.
Edited by SpiceWare
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That's pretty cool, didn't realize there were demos on the VIC! Looks like they were doing raster interrupts in it, but the VIC doesn't have raster interrupts... :ponder: Probably doing timer interrupts to simulate raster interrupts.

 

EDIT: Yep, VIC raster interrupts are simulated by using interrupts on 2 timers - Making stable raster routines (C64 and VIC-20)

On the VIC-20, there is no Raster interrupt feature in the video chip. All you can do is to use a timer for generating raster interrupts. And if you use two timers running at a constant phase difference, you can get full synchronization. The first timer generates the raster interrupt, and the second timer, the auxiliary timer, tells the raster routine where it is running.

This is probably as advanced as simulated raster interrupts gets on the VIC-20, based on Marko Makela's routine(!), runs fine in winvice in unexpanded mode: happyhour.zip (Slightly off topic maybe, but I still find it interesting to compare demos between the VCS and VIC-20...)

 

Regards,

Moderntimes99

Edited by moderntimes99
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