DPC+ Player2-9 playfield collisions

[+Lewis2907]

I'm going through the example programs I have and searching the forum, but I can't find an example for DPC using player2 playfield detection. I'm okay with the bouncy effect as I know the smooth effect that RT likes to use is difficult and takes time. It's been a while since I have played with Bb and I'm almost relearning some stuff and looking at things differently as well since I took a break from Bb as a hobby. 

 

Below is a snippet of the code I'm using. 

 

   ;***************************************************************
   ;***************************************************************
   ;
   ;  Player 1 movement and boundaries 
   ;
   if collision(playfield,player1) then gosub __Knock_Player_Back
   gosub __Move_Enemy

 

__Knock_Player_Back
   player1x = player1x - P1_X
   player1y = player1y - P1_Y
   return

 

**************************What I would like to use or something simple (DPC+ is not simple lol)********************************

 

   ;***************************************************************
   ;***************************************************************
   ;
   ;  Player 2 movement and boundaries 
   ;
   if collision(playfield,player2) then gosub __Knock_Player_Back
   gosub __Move_Enemy2

 

__Knock_Player_Back2
   player2x = player2x - P2_X
   player2y = player2y - P2_Y
   return

 

 

 

[CapitanClassic]

Because P2-P9 are virtual sprites (and actually share P1 sprite), you cannot do simple collisions with the playfield like you do with P0. (why aren’t you using player0 for first player, and player1 for second player)

 

What I did was set the kernel option to improve collision detection with virtual sprites.

 

Quote

set kernel_options collision(player1,playfield)

Then I track the x/y position of the virtual sprite against the “on” playfield pixels.

 

; get player position with respect to playfield pixels
; temp2 will contain the P1 sprites upper-left location in 4x4 pf pixels
; temp3 is P1 upper-left y position in pf pixels
temp2 = (player1x - 16) / 4
tenp3 = (player1y/4)

; did some other math here,
; because my spites are bigger than 1 playfield pixel

; check for collisions
if pfread(temp2,temp3) then goto __handleP1PfCollision

 

https://www.randomterrain.com/atari-2600-memories-batari-basic-commands.html

Quote

When a virtual sprite collides with the playfield, you won't know exactly which one did it without coordinate checking.

PS: you must drawscreen before doing any collisions.

Edited November 26, 2020 by CapitanClassic

[+Lewis2907]

Thanks. I forgot about swapping the players out in DPC. It's been like 1.5 years if not longer since I really had time to play around with Bb and I kinda forgot some stuff. I'm looking at my old stuff and the notes I have in there to help me remember. Thanks again.

[+Gemintronic]

I think previously people have attempted to come up with assembly routines that treats the playfield data as a collision mask.

 

Still in the baby stages with 6502 and 68k assembly myself.. someday!