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Forum Index : Microcontroller and PC projects : CMM2: Framebuffer commands

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electrotrains
Newbie

Joined: 29/07/2020
Location: United Kingdom
Posts: 11
Posted: 09:37am 03 Aug 2020
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Hi,

I'm trying to work out if the FRAMEBUFFER commands will help me in my attempt to write a scrolling, tile-based game in MODE 3,16 (320x200 16-bit).

Is the framebuffer really just like a PAGE, and differs only in that it can be bigger than the selected MODE resolution?
PAGE 0 is still what is visible on screen?

So I could do something like:
MODE 3,16
FRAMEBUFFER CREATE 640,480
FRAMEBUFFER WRITE
DO
' drawing to a 640x400 framebuffer goes here
' now we copy a 320x200 'window' to page 0
FRAMEBUFFER WINDOW x,y,0,B
LOOP

and I could have a 640x400 map, with a scrolling 320x200 region visible on screen?

Is using a FRAMEBUFFER to do this faster than just PAGE SCROLLing an offscreen page,  BLIT new tiles into the gaps, then doing a PAGE COPY to 0 to finally display?

Robin
https://github.com/robinhedwards
 
matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 3869
Posted: 10:41am 03 Aug 2020
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  Quote  Is the framebuffer really just like a PAGE, and differs only in that it can be bigger than the selected MODE resolution?
PAGE 0 is still what is visible on screen?


Yes and Yes

  Quote  Is using a FRAMEBUFFER to do this faster than just PAGE SCROLLing an offscreen page


Probably slightly but should be conceptually simpler
 
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