C64-dev/examples/sprite-demo.bas

1 REM ============================================
2 REM  SPRITE-DEMO.BAS - C64 Hardware Sprite Demo
3 REM  Demonstrates: sprite setup, movement,
4 REM  color, enable/disable
5 REM ============================================
10 REM --- CONSTANTS ---
20 SP = 53248  : REM VIC-II base ($D000)
30 SPENA = SP+21 : REM sprite enable register ($D015)
40 EXTCOL = SP+32 : REM border color ($D020)
50 BGCOL = SP+33  : REM background color ($D021)
60 SPPTR = 2040   : REM sprite 0 pointer (screen RAM + $03F8)

100 REM --- SETUP ---
110 POKE BGCOL, 0   : REM black background
120 POKE EXTCOL, 0  : REM black border
130 PRINT CHR$(147)  : REM clear screen

200 REM --- DEFINE SPRITE SHAPE (block 13 = $0340) ---
210 FOR I = 832 TO 894 : POKE I, 0 : NEXT : REM clear block 13

220 REM Draw a simple arrow shape (24 pixels wide x 21 rows)
230 REM Each row = 3 bytes
240 DATA 0,60,0,0,126,0,0,255,0,1,255,128
250 DATA 3,255,192,7,255,224,0,60,0,0,60,0
260 DATA 0,60,0,0,60,0,0,60,0,0,60,0
270 DATA 0,60,0,0,60,0,0,60,0,0,60,0
280 DATA 0,60,0,0,60,0,0,60,0,0,60,0
290 DATA 0,60,0

300 FOR I = 0 TO 62
310   READ D : POKE 832+I, D
320 NEXT I

400 REM --- POINT SPRITE 0 TO BLOCK 13 ---
410 POKE SPPTR, 13      : REM sprite 0 uses block 13

420 REM --- SET SPRITE COLOR ---
430 POKE SP+39, 7       : REM sprite 0 color = yellow ($D027)

440 REM --- ENABLE SPRITE 0 ---
450 POKE SPENA, 1       : REM enable sprite 0 bit 0

500 REM --- ANIMATE: BOUNCE SPRITE ACROSS SCREEN ---
510 X = 40 : Y = 100 : DX = 2 : DY = 1

520 FOR F = 1 TO 500
530   X = X + DX : Y = Y + DY

540   REM Bounce off edges
550   IF X < 24 OR X > 294 THEN DX = -DX
560   IF Y < 50 OR Y > 220 THEN DY = -DY

570   REM Set position
580   IF X > 255 THEN POKE SP+16,(PEEK(SP+16) OR 1) : POKE SP,X-256
590   IF X <= 255 THEN POKE SP+16,(PEEK(SP+16) AND 254) : POKE SP,X
600   POKE SP+1, Y      : REM Y position

610   REM Cycle border color every 10 frames
620   IF (F AND 15) = 0 THEN POKE EXTCOL, (PEEK(EXTCOL)+1) AND 15

630 NEXT F

700 REM --- CLEAN UP ---
710 POKE SPENA, 0       : REM disable all sprites
720 POKE BGCOL, 6       : REM restore blue background
730 POKE EXTCOL, 14     : REM restore light blue border
740 PRINT "DONE."
750 END