Author Topic: Multiple CRTC Screens possible or not? and practical or not?  (Read 162 times)

0 Members and 1 Guest are viewing this topic.

Offline zhulien

  • 6128 Plus
  • ******
  • Posts: 788
  • Country: au
  • aka Vorax
    • 8bitology
  • Liked: 319
  • Likes Given: 339
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?

Offline GUNHED

  • 6128 Plus
  • ******
  • Posts: 2.799
  • Country: de
  • Reincarnation of TFM
    • FutureOS - The quickest OS for the CPC and Plus
  • Liked: 1301
  • Likes Given: 3035
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.
http://futureos.de --> Get the revolutionary FutureOS (Update: 2021.01.24)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.07.15)

Offline Targhan

  • Supporter
  • 6128 Plus
  • *
  • Posts: 1.403
  • Country: fr
  • Liked: 1331
  • Likes Given: 195
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.
Targhan/Arkos

Arkos Tracker 2.0.1 now released! - Follow the news on Twitter!
Disark - A cross-platform Z80 disassembler/source converter
FDC Tool 1.1 - Read Amsdos files without the system

Imperial Mahjong
Orion Prime