0 REM * * * * * * * ** * * * * * * *
1 REM *                            *
2 REM *     SPRITE  PRIORITIES     *
3 REM *        A BASIC DEMO        *
4 REM *          BY BONES          *
5 REM *                            *
6 REM * * * * * * * ** * * * * * * *
7 :
8 :
9 :
10 GOSUB66:REM  * INITIALISE
11 :
12 REM ***** PROGRAM MAINLOOP *****
13 :
14 GOSUB55:REM  * KEYPRESS
15 JV=PEEK(JS)AND15:IFJV=15THEN14
16 GOSUB21:REM EXECUTE JOY COMMANDS
17 GOTO14
18 :
19 REM     *** JOYSTICK UP ***
20 :
21 IFJV<>14THEN32
22 DS(K)=DS(K)-4:IFDS(K)<50THENDS(K)=50
23 POKEV+1+(N*2),DS(K)
24 IFPEEK(V+3+(N*2))<=PEEK(V+1+(N*2))THEN28
25 SYS52832:REM * PRIORITISE SPRITES
26 N=N+1:IFN>7THENN=7
27 IFN<>0THENGOSUB64
28 RETURN
29 :
30 REM   *** JOYSTICK DOWN ***
31 :
32 IFJV<>13THEN43
33 DS(K)=DS(K)+4:IFDS(K)>208THENDS(K)=208
34 POKEV+1+(N*2),DS(K)
35 IFPEEK(V+1+(N*2))<=PEEK(V-1+(N*2))THEN39
36 SYS52832:REM * PRIORITISE SPRITES
37 IFN<>0THEN GOSUB64
38 N=N-1:IFN<0THENN=0
39 RETURN
40 :
41 REM  *** JOYSTICK LEFT/RIGHT ***
42 :
43 Y=PEEK(V+(N*2))
44 IFJV<>11THEN47
45 Y=Y-6:IFY<24THENY=24
46 GOTO49
47 IFJV<>7THEN23
48 Y=Y+6:IFY>255THENY=255
49 POKEV+(N*2),Y
50 RETURN
51 :
52 REM   *** SELECT-A-SPRITE ***
53 REM     *   KEYS 1 TO 8   *
54 :
55 GETK$:X=VAL(K$):IFX<1ORX>8THEN60
56 K=X-1
57 FORC=0TO7
58 IFF(C)=KTHENN=C
59 NEXT
60 RETURN
61 :
62 REM  *** UPDATE F(LAG) ARRAY ***
63 :
64 Z=F(N):F(N)=F(N-1):F(N-1)=Z:RETURN
65 :
66 REM     *** INITIALISE ***
67 :
68 POKE53280,0:POKE53281,0:PRINT"[147]"
69 V=53248:JS=56320:DP=2040:PO=192:DIMDS(7),F(7):N=0:JV=0:K=0:
70 FORC=0TO64:POKE12288+C,255:NEXT:REM * FILL SPRITE IMAGES WITH BLANKS
71 FORC=0TO7:POKEDP+C,PO:REM * DATA POINTERS
72 REM
73 REM
74 REM
75 POKEV+39+C,C+1:REM * COLOUR SPRITES
76 NEXTC
77 X=50:FORC=0TO14STEP2:POKEV+C,X:X=X+10:NEXT:REM * POKE X COORDS
78 Y=200:FORC=1TO15STEP2:POKEV+C,Y:Y=Y-10:NEXT:REM * POKE Y COORDS
79 FORC=0TO7:DS(C)=PEEK(V+1+(C*2)):F(C)=C:NEXT:REM * SET UP ARRAYS
80 POKEV+21,255:REM * ENABLE SPRITES
81 RETURN