Starting a Fight
Trigger combat when the player walks into a monster — switch from exploration to a combat screen.
Walking into a monster starts a fight. The screen switches from the dungeon viewport to a combat display showing the monster name, both HP values, and the player options: attack or flee. This unit builds the combat trigger and the initial combat screen. The actual damage calculations come in the next unit — for now, the structure is in place.
The Program
5 REM === DUNGEONS OF DORIN ===
10 BORDER 0: PAPER 0: INK 7: CLS
20 PRINT AT 3, 4; INK 7; BRIGHT 1; "DUNGEONS OF DORIN"
30 PRINT AT 6, 2; INK 6; "Descend ten floors of"
35 PRINT AT 7, 2; INK 6; "darkness. Find the Heart."
40 PRINT AT 10, 2; INK 7; "Q/A = up/down"
42 PRINT AT 11, 2; INK 7; "O/P = left/right"
44 PRINT AT 14, 2; INK 7; "Press any key to begin"
50 PAUSE 0
60 CLS
70 REM === define stats ===
80 LET h = 20: LET z = 20: LET a = 3: LET f = 2
82 LET g = 0: LET e = 1
84 DIM d(16,16): DIM v(16,16)
86 DIM j(5): DIM k(5): DIM l(5): DIM n(5)
90 REM === generate floor ===
92 GO SUB 1000
94 LET x = u(1,1) + 1: LET y = u(1,2) + 1
96 LET t = u(s,1) + 1: LET t2 = u(s,2) + 1
98 IF t >= 1 AND t <= 16 AND t2 >= 1 AND t2 <= 16 THEN LET d(t2,t) = 2
100 REM place monsters
102 LET t = INT (RND * 3) + 2
104 IF t > 5 THEN LET t = 5
106 LET m = t
108 FOR i = 1 TO m
110 GO SUB 1600
112 LET j(i) = t: LET k(i) = t2
114 LET l(i) = 1: LET n(i) = 4
116 NEXT i
118 GO SUB 380
120 CLS
122 GO SUB 300
124 GO SUB 500
126 REM === main loop ===
128 PAUSE 0: LET i$ = INKEY$
130 LET t = x: LET t2 = y
132 IF i$ = "q" OR i$ = "Q" THEN LET t2 = y - 1
134 IF i$ = "a" OR i$ = "A" THEN LET t2 = y + 1
136 IF i$ = "o" OR i$ = "O" THEN LET t = x - 1
138 IF i$ = "p" OR i$ = "P" THEN LET t = x + 1
140 IF t = x AND t2 = y THEN GO TO 126
142 IF t < 1 OR t > 16 OR t2 < 1 OR t2 > 16 THEN GO TO 126
144 IF d(t2,t) = 1 THEN GO TO 126
146 REM check monster collision
148 FOR c = 1 TO m
150 IF j(c) = t AND k(c) = t2 AND n(c) > 0 THEN LET i = c: GO SUB 800: GO TO 162
152 NEXT c
154 LET x = t: LET y = t2
156 IF d(y,x) = 2 THEN GO SUB 600: GO TO 126
158 GO SUB 380
162 GO SUB 300
164 GO SUB 500
166 GO TO 126
300 REM === draw viewport ===
302 FOR c = -3 TO 3
304 FOR o = -3 TO 3
306 LET t = x + o: LET t2 = y + c
308 LET i = 1: LET i2 = 0
310 IF t < 1 OR t > 16 OR t2 < 1 OR t2 > 16 THEN GO TO 340
312 IF v(t2,t) = 0 THEN GO TO 340
314 LET i = d(t2,t)
316 LET i2 = 7
318 IF i = 1 THEN LET i2 = 4
320 FOR s = 1 TO m
322 IF j(s) = t AND k(s) = t2 AND n(s) > 0 THEN LET i2 = 2: LET i = 5
324 NEXT s
340 LET t3 = 3 + c: LET t4 = 11 + o
342 IF o = 0 AND c = 0 THEN LET i2 = 7: LET i = 6
344 IF i2 = 0 THEN PRINT AT t3, t4; " ": GO TO 370
346 IF i = 0 THEN PRINT AT t3, t4; INK i2; ".": GO TO 370
348 IF i = 1 THEN PRINT AT t3, t4; INK i2; CHR$ 143: GO TO 370
350 IF i = 2 THEN PRINT AT t3, t4; INK i2; ">": GO TO 370
352 IF i = 5 THEN PRINT AT t3, t4; INK i2; "M": GO TO 370
354 IF i = 6 THEN PRINT AT t3, t4; INK i2; "@": GO TO 370
356 PRINT AT t3, t4; INK i2; "?"
370 NEXT o: NEXT c
372 RETURN
380 REM === update visibility ===
382 FOR c = y - 2 TO y + 2
384 FOR o = x - 2 TO x + 2
386 IF c >= 1 AND c <= 16 AND o >= 1 AND o <= 16 THEN LET v(c,o) = 1
388 NEXT o: NEXT c
390 RETURN
500 REM === draw status ===
502 PRINT AT 8, 2; INK 7; "HP:"; h; "/"; z; " "
504 PRINT AT 9, 2; INK 4; "AT:"; a; " "
506 PRINT AT 10, 2; INK 5; "DF:"; f; " "
508 PRINT AT 8, 20; INK 6; "FL:"; e; " "
510 PRINT AT 9, 20; INK 6; "AU:"; g; " "
514 RETURN
600 REM === stairs down ===
602 LET e = e + 1
604 IF e > 10 THEN GO TO 1100
606 PRINT AT 12, 5; INK 7; BRIGHT 1; "DESCENDING..."
608 PAUSE 30
610 GO TO 90
800 REM === combat (simple) ===
802 CLS
804 PRINT AT 0, 0; INK 2; BRIGHT 1; "COMBAT: Rat"
806 PRINT AT 2, 0; INK 7; "Your HP: "; h; " Enemy HP: "; n(i)
810 REM combat loop
812 PRINT AT 5, 0; INK 7; "A)ttack"
814 PAUSE 0: LET i$ = INKEY$
816 IF i$ <> "a" AND i$ <> "A" THEN GO TO 814
818 REM player attacks for 1 damage
820 LET n(i) = n(i) - 1
822 PRINT AT 8, 0; INK 4; "You hit for 1! "
824 IF n(i) <= 0 THEN GO TO 850
826 PRINT AT 2, 0; INK 7; "Your HP: "; h; " Enemy HP: "; n(i); " "
828 PAUSE 20
830 GO TO 810
850 REM enemy defeated
852 PRINT AT 12, 0; INK 4; BRIGHT 1; "VICTORY!"
854 LET n(i) = 0
856 PAUSE 30
858 CLS
860 RETURN
1000 REM === generate floor subroutine ===
1002 FOR i = 1 TO 16: FOR o = 1 TO 16
1004 LET d(i,o) = 1: LET v(i,o) = 0
1006 NEXT o: NEXT i
1010 LET s = INT (RND * 3) + 3
1012 DIM u(5,4)
1014 FOR i = 1 TO s
1016 LET u(i,1) = INT (RND * 10) + 2
1018 LET u(i,2) = INT (RND * 10) + 2
1020 LET u(i,3) = INT (RND * 4) + 3
1022 LET u(i,4) = INT (RND * 4) + 3
1024 FOR c = u(i,2) TO u(i,2) + u(i,4) - 1
1026 FOR o = u(i,1) TO u(i,1) + u(i,3) - 1
1028 IF c >= 1 AND c <= 16 AND o >= 1 AND o <= 16 THEN LET d(c,o) = 0
1030 NEXT o: NEXT c
1032 NEXT i
1034 FOR i = 1 TO s - 1
1036 LET t = u(i,1) + INT (u(i,3) / 2)
1038 LET t2 = u(i,2) + INT (u(i,4) / 2)
1040 LET t3 = u(i+1,1) + INT (u(i+1,3) / 2)
1042 LET t4 = u(i+1,2) + INT (u(i+1,4) / 2)
1044 IF t <= t3 THEN FOR o = t TO t3: IF t2 >= 1 AND t2 <= 16 AND o >= 1 AND o <= 16 THEN LET d(t2,o) = 0
1046 IF t <= t3 THEN NEXT o
1048 IF t > t3 THEN FOR o = t3 TO t: IF t2 >= 1 AND t2 <= 16 AND o >= 1 AND o <= 16 THEN LET d(t2,o) = 0
1050 IF t > t3 THEN NEXT o
1052 IF t2 <= t4 THEN FOR c = t2 TO t4: IF c >= 1 AND c <= 16 AND t3 >= 1 AND t3 <= 16 THEN LET d(c,t3) = 0
1054 IF t2 <= t4 THEN NEXT c
1056 IF t2 > t4 THEN FOR c = t4 TO t2: IF c >= 1 AND c <= 16 AND t3 >= 1 AND t3 <= 16 THEN LET d(c,t3) = 0
1058 IF t2 > t4 THEN NEXT c
1060 NEXT i
1062 RETURN
1100 REM === victory (placeholder) ===
1102 CLS
1104 PRINT AT 8, 4; INK 7; BRIGHT 1; "YOU FOUND THE HEART!"
1106 PRINT AT 12, 6; INK 7; "Press any key"
1108 PAUSE 0
1110 STOP
1600 REM === find empty cell ===
1602 LET t = INT (RND * 14) + 2
1604 LET t2 = INT (RND * 14) + 2
1606 IF d(t2,t) <> 0 THEN GO TO 1602
1608 IF t = x AND t2 = y THEN GO TO 1602
1610 RETURN
How It Works
Lines 180-184 check for monster collision during movement. Before the player moves to a new cell, a loop checks all monster positions. If a living monster (HP greater than 0) occupies the target cell, combat begins. The variable i is set to the monster index, and the combat subroutine at line 800 is called.
Lines 800-814 set up the combat screen. The monster type index l(i) is used to READ the monster DATA for its name, stats, and gold value. CLS clears the screen to make room for the combat display.
Line 814 prints the combat header: “COMBAT:” followed by the monster name in red, bright text. This immediately tells the player what they are fighting.
Line 816 shows both HP values — the player current HP and the monster current HP. Seeing both numbers lets the player judge whether to fight or flee.
Lines 822-828 present the combat menu: A to attack, F to flee. PAUSE 0 waits for input. Invalid keys loop back to wait again.
Mode Switching
The combat trigger represents a mode switch. The program has two distinct modes: exploration (viewport, movement, fog of war) and combat (text-based, turn-by-turn). The switch happens when the player walks into a monster, and switches back when combat ends (through victory, death, or fleeing).
CLS is the visual marker of this transition. The dungeon disappears and the combat screen takes its place. When combat ends, the dungeon redraws. This is not subtle, but it is clear — the player always knows which mode they are in.
DATA and RESTORE
The combat setup uses RESTORE 1500 to reset the DATA pointer to the monster table, then READs forward to the correct entry. This is the standard pattern for accessing specific records in a DATA block when you know the index. The loop on line 806 skips entries before the target, and line 808 reads the one that matches.
Try This
Add monster descriptions. Below the combat header, print a short line describing the monster — “A snarling rat” or “Bones held together by dark magic”. Use IF statements on the monster type to choose the text.
Show the player stats. Display attack and defence alongside HP in the combat screen. The player needs this information to judge whether they can win the fight.