EGFX · FUNCTION 20ALPHA · USE AT YOUR OWN RISK
SNAKE_STEP
Move a sprite snake.
Moves the selected snake head and updates its history.
The snake draws through COMPACT_SPRITE (37).
Parameters
| Name | Order | Description |
|---|---|---|
ID | 8 | Snake ID. |
HEAD X | 9–10 | Signed head X. |
HEAD Y | 11–12 | Signed head Y. |
BASIC example
Tested listing: snake-demo.bas.
5 REM Disk-defined sprites; two independent head-following snakes. Q quits.
10 MODE 1:HIMEM=&2400
20 PROCeginit:PROCegloadsprites("SPRITES",6)
30 PROCegsnake(0,12,2,0,1,2):PROCegsnake(1,8,1,3,3,3):t%=0
40 REPEAT
50 PROCegsnakestep(0,150+90*SIN(t%/10),100+60*COS(t%/10))
60 PROCegsnakestep(1,150+70*SIN(t%/13),120+70*COS(t%/13))
70 PROCegbegin:PROCegsnakedraw(0):PROCegsnakedraw(1):PROCegpresent
80 t%=(t%+1) MOD 256
90 UNTIL INKEY(0)=81
100 MODE 7:END
Assembly example
JSR init_egfx
JSR begin_frame
LDA #20 : JSR eg_call
JSR present_frame
RTS