Jump to content

Photo

CTRLPF Per Player?


4 replies to this topic

#1 Cybearg OFFLINE  

Cybearg

    Dragonstomper

  • 950 posts

Posted Mon Jul 15, 2013 3:36 PM

So I'm in a situation where I'd like one player to move behind the playfield while another player moves in front of the playfield. Is there any modification that can be made (not worried if it costs extra memory) to the kernel to allow for this?

#2 Random Terrain ONLINE  

Random Terrain

    Visual batari Basic User

  • 28,779 posts
  • Controlled Randomness
    Replay Value
    Nonlinear
  • Location:North Carolina (USA)

Posted Mon Jul 15, 2013 3:39 PM

Did you check out the related links here:

randomterrain.com/atari-2600-memories-batari-basic-commands.html#ctrlpf

Might be something similar to what you want there.

#3 SpiceWare ONLINE  

SpiceWare

    Draconian

  • 12,411 posts
  • Medieval Mayhem
  • Location:Planet Houston

Posted Mon Jul 15, 2013 3:50 PM

CTRLPF = Control PlayField. If the above/below setting was per player it would be controlled via something like one of the unused bits (D7, D6 or D3) found in NUSIZ0 and NUSIZ1.

There is a way around it, but it will use a lot of RAM and CPU. You'd have to define the "behind playfield" player's graphic data to be stored in RAM, then you'd have to manually zero out any bits that would be blocked by a playfield pixel.

Edited by SpiceWare, Mon Jul 15, 2013 3:51 PM.


#4 Cybearg OFFLINE  

Cybearg

    Dragonstomper

  • Topic Starter
  • 950 posts

Posted Mon Jul 15, 2013 4:16 PM

CTRLPF = Control PlayField. If the above/below setting was per player it would be controlled via something like one of the unused bits (D7, D6 or D3) found in NUSIZ0 and NUSIZ1.

There is a way around it, but it will use a lot of RAM and CPU. You'd have to define the "behind playfield" player's graphic data to be stored in RAM, then you'd have to manually zero out any bits that would be blocked by a playfield pixel.


Thanks, this is the response I was looking for, unfortunate as it may be. Thanks for letting me know.

#5 freshbrood OFFLINE  

freshbrood

    Star Raider

  • 80 posts

Posted Wed Jul 18, 2018 1:43 AM

One quick and dirty way to achieve this illusion would be to constantly leave both players in front of the playfield, but to change all the colors of the player "behind" the playfield to the same colors as the playfield. This would essentially make it "disappear" while behind it.




0 user(s) are browsing this forum

0 members, 0 guests, 0 anonymous users