basic movement

maze.tal

@@ -30,11 +30,11 @@
 %SOUTH { COLS }
 %WEST { #ffff }
 
-%CELL { SWP2 COLS MUL2 ADD2 } ( col* row* -> row*cols+col )
+%CELL { SWP2 COLS MUL2 ADD2 } ( row* col* -> row*cols+col )
 %LOAD { ;maze ADD2 LDA } ( cell* -> val^ )
 %STORE { ;maze ADD2 STA } ( val cell* -> )
 %XSTORE { ROT ROT STORE } ( cell* val -> )
-%IS-START { LOAD #04 AND #02 SFT } ( cell* -> bool^ )
+%IS-OPEN { LOAD #01 AND }
 %UNSEEN { LOAD #02 AND #00 EQU } ( cell* -> bool^ )
 %PATH { ADD2 #0002 DIV2 } ( cell1* cell2* -> cell3* )
 
@@ -74,6 +74,10 @@
 ( boolean used to generate a new maze )
 @regenerate $1
 
+( cell occupied by the character )
+@charx $2
+@chary $2
+
 |0100
 
     ( intialize rng )
@@ -89,6 +93,10 @@
     #02 .directions #02 ADD STZ
     #03 .directions #03 ADD STZ
 
+    ( initialize the character )
+    #0002 .charx STZ2
+    #0000 .chary STZ2
+
     ( initialize cell offsets - calculated based on #columns )
     NORTH .cell-offsets #00 ADD STZ2
     EAST .cell-offsets #02 ADD STZ2
@@ -142,9 +150,35 @@ BRK
     &done
 BRK
 
+%DIGIT { #00 SWP ;digits ADD2 LDA EMIT }
+%EMIT-BYTE { DUP #04 SFT DIGIT #0f AND DIGIT }
+%EMIT-SHORT { SWP EMIT-BYTE EMIT-BYTE }
+
+@try-move ( drow dcol -> )
+    .charx LDZ2 ADD2 SWP2 ( col+dcol row+drow )
+    .chary LDZ2 ADD2 SWP2 ( row+drow dcol )
+    OVR2 OVR2 ( row col row col )
+    CELL LOAD ( col row val )
+    #01 AND ,&ok JCN
+    POP2 POP2 RTN
+    &ok .charx STZ2 .chary STZ2 RTN
+
 @on-key ( -> )
-    #01 .regenerate STZ
+    .Controller/button DEI
-BRK
+    DUP ,&move JCN
+    POP ( #01 .regenerate STZ ) BRK
+
+    &move-up    #ffff #0000 ;try-move JSR2 POP BRK
+    &move-down  #0001 #0000 ;try-move JSR2 POP BRK
+    &move-left  #0000 #ffff ;try-move JSR2 POP BRK
+    &move-right #0000 #0001 ;try-move JSR2 POP BRK
+
+    &move
+    DUP #10 AND ,&move-up JCN
+    DUP #20 AND ,&move-down JCN
+    DUP #40 AND ,&move-left JCN
+    DUP #80 AND ,&move-right JCN
+    EMIT-BYTE NEWLINE BRK
 
 @wall-sprite
     ffff ffff ffff ffff 
@@ -152,6 +186,9 @@ BRK
 @open-sprite
     0000 0000 0000 0000
 
+@char-sprite
+    0000 183c 3c18 0000
+
 @draw-maze ( -> )
     #0000 ( row )
     &loop
@@ -175,14 +212,28 @@ RTN
 @draw-cell ( row* col* -> )
     SWP2 DUP2 #0008 MUL2 .Screen/y DEO2 ( draw at y=row*8 )
     SWP2 DUP2 #0008 MUL2 .Screen/x DEO2 ( draw at x=col*8 )
-    CELL LOAD ( load cell byte at maze+index )
+
+    OVR2 OVR2 
+    .charx LDZ2 EQU2 STH
+    .chary LDZ2 EQU2 STHr AND
+    ,&draw-char JCN
+
+    ( OVR2 OVR2 ) CELL LOAD ( load cell byte at maze+index )
     #01 AND ( get bit 1, wall bit )
+    ,&draw-open JCN
+    ( POP2 POP2 ) ;wall-sprite ,&end JMP
+
+    &draw-open
+(    .charx LDZ2 EQU2 STH
+    .chary LDZ2 EQU2 STHr AND
+    ,&draw-char JCN )
+    ;open-sprite ,&end JMP
+
+    &draw-char
+    [ POP2 POP2 ] ;char-sprite ,&end JMP
 
-    ;open-sprite .Screen/addr DEO2 ( set to wall sprite initially )
-    ,&end JCN ( if cell byte is non-zero, space is open )
-    ;wall-sprite .Screen/addr DEO2 ( if we got here not a wall )
     &end
-
+    .Screen/addr DEO2
     .tint LDZ .Screen/sprite DEO ( draw the cell )
 RTN
 
@@ -337,3 +388,8 @@ we use the link to support backtracking without
 needing a separate stack.
 )
 @maze $2560
+
+( convenience for less branching when printing hex )
+@digits
+    30 31 32 33 34 35 36 37
+    38 39 61 62 63 64 65 66