grdevdemo.bas

1 REM GRAPHICS DISPLAY DEVICE DEMO
2 REM BASE ADDRESS $FFE2
3 REM DRAW HORIZONTAL AND VERTICAL LINES
4 REM DRAW SINUSOID
10 GB=65506:REM SET BASE ADDRESS
12 REM INITIALIZE, SET COLORS
15 POKE GB+1,0:POKE GB+11,0
16 POKE GB+3,0:POKE GB+4,255:POKE GB+5,0
17 POKE GB+6,0:POKE GB+7,0:POKE GB+8,0
18 POKE GB+9,3:POKE GB+9,4:POKE GB+9,0
19 GOSUB 1120:REM DRAW SINUSOID
20 Y=100:REM X-AXIS
30 GOSUB 1000
50 X=100:REM Y-AXIS
60 GOSUB 1060
70 REM SOME EXTRA DOTTED LINES
80 Y=50:GOSUB 1200
90 Y=150:GOSUB 1200
100 X=50:GOSUB 1260
110 X=150:GOSUB 1260
120 PRINT "... HIT [SPACE] TO END ..."
125 GET K$:IF K$=" " THEN END
130 FOR I=1 TO 2000:NEXT I:REM SHORT PAUSE
140 GOTO 15
998 END
999 REM ------- SUBROUTINES SECTION -------
1000 REM DRAW HORIZONTAL LINE AT Y
1005 POKE GB+2,Y
1006 POKE GB+12,Y
1020 POKE GB,0
1025 POKE GB+10,199:POKE GB+9,5
1050 RETURN
1060 REM DRAW VERTICAL LINE AT X
1070 POKE GB,X
1075 POKE GB+10,X
1090 POKE GB+2,0
1095 POKE GB+12,199:POKE GB+9,5
1110 RETURN
1120 REM SINUSOID
1130 FOR X=0 TO 199-4 STEP 5
1140 XX=X*(6.28/200)
1145 XE=(X+5)*(6.28/200)
1150 YY=SIN(XX):YE=SIN(XE)
1160 Y=199-INT((YY+1)*100)
1165 Y2=199-INT((YE+1)*100)
1170 POKE GB,X:POKE GB+2,Y
1175 POKE GB+10,X+5:POKE GB+12,Y2:POKE GB+9,5
1180 NEXT X
1190 RETURN
1200 REM DRAW DOTTED HORIZONTAL LINE AT Y
1205 POKE GB+2,Y
1210 FOR X=0 TO 199 STEP 4
1220 POKE GB,X
1230 POKE GB+9,1
1240 NEXT X
1250 RETURN
1260 REM DRAW DOTTED VERTICAL LINE AT X
1270 POKE GB,X
1280 FOR Y=0 TO 199 STEP 4
1290 POKE GB+2,Y
1300 POKE GB+9,1
1310 NEXT Y
1320 RETURN