Author Topic: Multiple CRTC Screens possible or not? and practical or not?  (Read 460 times)

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Offline zhulien

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Hi Everyone,


I know that we have the ability to change CRTC registers part way down the screen to eg: created split screen modes.


Can other CRTC registers also be changed so you effectively have 2 totally independent screens within a single CRTC?


For example, very tall but quarter sized width screens on the left and right?  If that is possible, can it be practical to be two sprites without a background on a non-plus machine with the smoothness of hardware sprites moving the 2 screens around independently?  eg: could you make Way of the Exploding Fist type game using two giant perfectly smooth moving screens?


Perhaps a horizon can be done via rasters to have the largest smooth sprite fighting game ever on CPC?
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Offline GUNHED

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Re: Multiple CRTC Screens possible or not? and practical or not?
« Reply #1 on: 01:07, 21 September 21 »
Can other CRTC registers also be changed so you effectively have 2 totally independent screens within a single CRTC?
Yes, that's what I do in 'Return of the Sisters' and 'Gerelakos'. Two 16 KB screens. Well, in my case the get together to one 32 KB overscan screen.

It's also possible to have space in between.
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Offline Targhan

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Re: Multiple CRTC Screens possible or not? and practical or not?
« Reply #2 on: 10:10, 21 September 21 »
For vertical screen splitting, you can check the venerable SandKoh introduction. However, don't ever try to think you can make a game from this technique... It's simply not practical.
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Offline zhulien

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Re: Multiple CRTC Screens possible or not? and practical or not?
« Reply #3 on: 20:26, 21 September 21 »
Yes, that's what I do in 'Return of the Sisters' and 'Gerelakos'.


Impressive!
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Offline zhulien

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Re: Multiple CRTC Screens possible or not? and practical or not?
« Reply #4 on: 20:29, 21 September 21 »
However, don't ever try to think you can make a game from this technique... It's simply not practical.


I was thinking it could be possible to start small, like Atari 2600 small, but with huge smooth sprites (actually movable screens).


Perhaps driving 2 squares around the screen trying to bump the other into the side of the screen? or just damaging them but not yet necessarily having the score or damage displayed while playing?  Each square controlled by a separate player.


I guess the game would be needed to be thought of it fit in with the technique, not the other way around.
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Offline Targhan

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Re: Multiple CRTC Screens possible or not? and practical or not?
« Reply #5 on: 22:10, 21 September 21 »
You may, but you can also use specific software technique for that (you can move huge blocks by simply... shifting the borders, not what is inside!).
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