Hello
I managed to create a sliding screen in three pages of VRAM.
But during the scroll up and down, there were blank areas. Areas are assigned to the sprite and images!
I disable bit 1 of the VDP-9:
VDP-9: 0 - 0 - TP - CBD - VRS1 - VRS0 - SPD - B / W
SPD: 0/1 = disable / enable sprite
Sprites can trigger active SET PAGE 0.0, while
other pages 1,2 and 3 will be erased with vpoke
(212-255: canceled)
Ok?
This is my source for BASIC:
10 SCREEN 5 20 DATA "alto.sc5","centro.sc5","basso.sc5" 30 FOR L=0TO2:READA$:SET PAGE 0,1+L:BLOADA$,S:NEXTL 40 CALL TURBO ON 50 SET PAGE 0,0:L=256:V=4 60 REM 70 D=STICK(0):I$=INKEY$ 80 IF I$=CHR$(27) THEN GOTO 220 81 IF D=1 THEN L=L-V:IF L=<256 THEN L=256 82 IF D=5 THEN L=L+V:IF L=>814 THEN L=814 :REM 3*256+46=814!! 90 K=34:VDP(K+1)=(L AND &HFF):VDP(K+2)=(L AND &HFF00) /256 : REM SY 100 K=36:VDP(K+1)= 0:VDP(K+2) = 0 : REM DX 110 K=38:VDP(K+1)=40:VDP(K+2)=0 : REM DY 120 K=42:VDP(K+1)=168:VDP(K+2)= 0 : REM NY 130 K=45:C=0*8+0*4 : REM ARG 140 VDP(K+1)=C 150 K=46:VDP(K+1)=&HE0 160 WAIT &H99,129 : REM Z 170 LINE(0,10)-(255,10),6 180 REM 190 REM 200 rem 210 GOTO 60 220 REM 230 CALL TURBO OFF 240 REM 250 I$=INPUT$(1) 260 END
Note: three files "ALTO.SC5", "CENTRO.SC5" e "BASSO.SC5" : are part of a football field.
note2: WAIT &H99,129 is correct ?
the line 160 and 170 is "automatic" refresh to screen to run YMMM.
Bye bye
DanySoft
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