I was able to create a Double Buffer example using Locomotive BASIC and a little Sprite Driver I created, but am having problems with it.
I've setup CPC BASIC 3, so it generates an Assembly file, I can then modify the Assembly file, so the Code is relocated to &8000, leaving the Screen at &4000 available, I can then Assemble using the incliuded Pasmo Assembler, but I use Winape which lets me Pause and Load the Object file on the Debugger screen.
Like my earlier version I was trying to have working with Locomotive BASIC, the problem occurs when I try to move the Ball up the screen, I thought that perhaps some adjustments I'd made in this version from the original Locomotive would get it working, but it's not quite as clear cut.
I've setup CPC BASIC 3, so it generates an Assembly file, I can then modify the Assembly file, so the Code is relocated to &8000, leaving the Screen at &4000 available, I can then Assemble using the incliuded Pasmo Assembler, but I use Winape which lets me Pause and Load the Object file on the Debugger screen.
Like my earlier version I was trying to have working with Locomotive BASIC, the problem occurs when I try to move the Ball up the screen, I thought that perhaps some adjustments I'd made in this version from the original Locomotive would get it working, but it's not quite as clear cut.
- Code:
100 DEFWORD a-z:GOSUB 2000
110 MODE 0:BORDER 0:INK 0,3:INK 1,26:INK 2,21
120 CALL &A02E:CLS:CALL &A028:CLS:CALL &A02E
130 sc=2:x1=40:oy=720:ox=40
140 i=720:i1=720:y1=720
150 GOSUB 1310
160 WHILE 1
170 IF INKEY(2)=0 THEN IF y1<>1920 THEN GOSUB 1110
180 IF INKEY(0)=0 THEN IF y1>0 THEN GOSUB 1140
190 IF INKEY(1)=0 THEN IF x1<>76 THEN GOSUB 1170
200 IF INKEY(8)=0 THEN IF x1>0 THEN GOSUB 1200
210 WEND
220 END
800 ' Move Down
810 IF y1>&3FFF THEN i1=i+&50:i=i+&50:y1=i1
820 GOSUB 1410:GOSUB 1510
830 RETURN
840 IF y1>&3FFF THEN i1=i+&50:i=i+&50:y1=i1
850 GOSUB 1610:GOSUB 1310
860 RETURN
900 ' Move Up
910 IF y1<2 THEN i2=i+&37B0:i=i-&50:y1=i2
920 GOSUB 1410:GOSUB 1510
930 RETURN
940 IF y1<2 THEN i2=i+&37B0:i=i-&50:y1=i2
950 GOSUB 1610:GOSUB 1310
960 RETURN
1000 ' Move Right
1010 GOSUB 1410:GOSUB 1510
1020 RETURN
1050 ' Move Left
1060 GOSUB 1610:GOSUB 1310
1070 RETURN
1100 ' Check Screen Status and Move accordingly
1110 IF sc=1 THEN oy=z:y1=y1+&800:GOSUB 810:sc=2:RETURN
1120 IF sc=2 THEN oy=z:y1=y1+&800:GOSUB 840:sc=1:RETURN
1130 RETURN
1140 IF sc=1 THEN oy=z:y1=y1-&800:GOSUB 910:sc=2:RETURN
1150 IF sc=2 THEN oy=z:y1=y1-&800:GOSUB 940:sc=1:RETURN
1160 RETURN
1170 IF sc=1 THEN ox=w:x1=x1+1:GOSUB 1010:sc=2:CALL &BD19:RETURN
1180 IF sc=2 THEN ox=w:x1=x1+1:GOSUB 1060:sc=1:CALL &BD19:RETURN
1190 RETURN
1200 IF sc=1 THEN ox=w:x1=x1-1:GOSUB 1010:sc=2:CALL &BD19:RETURN
1210 IF sc=2 THEN ox=w:x1=x1-1:GOSUB 1060:sc=1:CALL &BD19:RETURN
1220 RETURN
1300 ' Draw screen to &4000
1310 s=&4000
1320 z=y1
1330 w=x1
1340 CALL &A000,&A036,(s+z)+w
1350 CALL &A028
1360 RETURN
1400 ' Clear Screen at &C000
1410 s=&C000
1420 oz=oy
1430 ow=ox
1440 CALL &A000,&A056,(s+oz)+ow
1450 RETURN
1500 ' Draw screen at &C000
1510 s=&C000
1520 z=y1
1530 w=x1
1540 CALL &A000,&A036,(s+z)+w
1550 CALL &A02E
1560 RETURN
1600 ' Clear Screeb at &4000
1610 s=&4000
1620 oz=oy
1630 ow=ox
1640 CALL &A000,&A056,(s+oz)+ow
1650 RETURN
2000 addr=&A000
2010 FOR ln=1 TO 7
2020 READ a$
2030 FOR p=1 TO 31 STEP 2
2040 POKE addr,VAL("&"+MID$(a$,p,2))
2050 addr=addr+1
2060 NEXT p:NEXT ln
2070 RETURN
2100 DATA DD6E02DD6603EBDD6E00DD66012234A0
2110 DATA 0608C506041A77132310FA2A34A0CD26
2120 DATA BC2234A0C110EBC93E40CD08BCC93EC0
2130 DATA CD08BCC900C000000000004080000084
2140 DATA 48000084480000844800008448000040
2150 DATA 80000000000000000000000000000000
2170 DATA 00000000000000000000000000000000
