Game 7 Unit 4 of 6 1 hr learning time

Pickups and Score

Scatter pickups in a second colour, then teach the look-ahead PEEK a new trick: tell wall from pickup from empty by the character code it reads. Roll over a pickup, collect it, and the score climbs on a status row that never disturbs the maze.

67% of Rover

Mark as complete Completed!

A maze with nothing to collect is just a corridor. Scatter some pickups — bright dots in their own colour — and give the rover a reason to explore. The clever part: the same look-ahead PEEK that spots a wall can tell a pickup apart from a wall, just by the character it finds.

10 POKE 53281,0:PRINT CHR$(147)
20 GOSUB 500
30 SC=0:GOSUB 700
40 R=4:C=5
50 POKE 1024+R*40+C,160:POKE 55296+R*40+C,7
60 J=PEEK(56320)
70 NR=R:NC=C
80 IF (J AND 1)=0 THEN NR=R-1
90 IF (J AND 2)=0 THEN NR=R+1
100 IF (J AND 4)=0 THEN NC=C-1
110 IF (J AND 8)=0 THEN NC=C+1
120 IF NR=R AND NC=C THEN 60
130 TC=PEEK(1024+NR*40+NC)
140 IF TC=160 THEN 60
150 IF TC=81 THEN SC=SC+10:GOSUB 700
160 POKE 1024+R*40+C,32
170 R=NR:C=NC
180 POKE 1024+R*40+C,160:POKE 55296+R*40+C,7
190 GOTO 60
500 FOR C=1 TO 38
510 POKE 1024+40+C,160:POKE 55296+40+C,1
520 POKE 1024+23*40+C,160:POKE 55296+23*40+C,1
530 NEXT C
540 FOR R=1 TO 23
550 POKE 1024+R*40+1,160:POKE 55296+R*40+1,1
560 POKE 1024+R*40+38,160:POKE 55296+R*40+38,1
570 NEXT R
580 FOR R=3 TO 12:POKE 1024+R*40+19,160:POKE 55296+R*40+19,1:NEXT R
590 FOR C=8 TO 30:POKE 1024+16*40+C,160:POKE 55296+16*40+C,1:NEXT C
600 POKE 1024+4*40+12,81:POKE 55296+4*40+12,3
610 POKE 1024+10*40+30,81:POKE 55296+10*40+30,3
620 POKE 1024+14*40+10,81:POKE 55296+14*40+10,3
630 POKE 1024+20*40+15,81:POKE 55296+20*40+15,3
640 POKE 1024+20*40+33,81:POKE 55296+20*40+33,3
650 RETURN
700 POKE 1024+1,19:POKE 1024+2,3:POKE 1024+3,15:POKE 1024+4,18:POKE 1024+5,5
710 FOR I=1 TO 5:POKE 55296+I,7:NEXT I
720 S$=STR$(SC)
730 FOR I=1 TO LEN(S$)
740 POKE 1024+6+I,ASC(MID$(S$,I,1)):POKE 55296+6+I,7
750 NEXT I
760 RETURN

A C64 maze with SCORE 10 on the top row, the rover mid-maze, and four cyan pickups scattered about. — Pickups scattered in cyan, a score on the status row. The rover has rolled over one — SCORE 10 — and four remain. The same PEEK that stops it at walls lets it through a pickup and counts it.

The pickups are POKEd in lines 600–640 — character 81, a round dot, in cyan (3) so they read as "go here", distinct from the white walls. The new cleverness is in the collision check. Line 130 now stores what the look-ahead PEEK finds: TC = PEEK(1024 + NR*40 + NC). Then line 140 blocks the move if TC is a wall (160), but line 150 does something new — if TC is a pickup (81), it adds 10 to the score SC and lets the rover move in. Rolling onto the pickup draws the rover over it, so it's collected and gone.

That's three outcomes from one read: wall (160) stops you, pickup (81) scores, anything else is open space you move into freely. The score itself is drawn by the routine at line 700, which POKEs SCORE and the number onto the top row — written straight to screen memory so updating it never scrolls or disturbs the maze below. Read the cell ahead, branch on what's there — the same pattern as walls, now doing more.

Try this

Worth more. Change the SC = SC+10 on line 150 to SC+25, or give different pickups different values by POKEing them as different characters and testing for each.
A pickup tone. Add a bright SID blip on collection (line 150) so a point is heard as well as seen — distinct from the bump tone, so your ear knows which happened.

What's next

You can collect and score, but the game never ends — there's always another pickup, or none left and nothing happens. In Unit 5 counting the pickups down gives the game a finish.