[Scummvm-cvs-logs] SF.net SVN: scummvm: [21593] scummvm/trunk/engines/lure/diassembly
dreammaster at users.sourceforge.net
dreammaster at users.sourceforge.net
Tue Apr 4 04:54:04 CEST 2006
Revision: 21593
Author: dreammaster
Date: 2006-04-04 04:53:45 -0700 (Tue, 04 Apr 2006)
ViewCVS: http://svn.sourceforge.net/scummvm/?rev=21593&view=rev
Log Message:
-----------
Completed disassembly of the Lure pathfinding code
Modified Paths:
--------------
scummvm/trunk/engines/lure/diassembly/LURE.ASM
scummvm/trunk/engines/lure/diassembly/Lure_notes.txt
Modified: scummvm/trunk/engines/lure/diassembly/LURE.ASM
===================================================================
--- scummvm/trunk/engines/lure/diassembly/LURE.ASM 2006-04-04 11:53:13 UTC (rev 21592)
+++ scummvm/trunk/engines/lure/diassembly/LURE.ASM 2006-04-04 11:53:45 UTC (rev 21593)
@@ -27,6 +27,11 @@
FULL_HORIZ_RECTS equ 18
FULL_VERT_RECTS equ 14
+ROOM_PATHS_WIDTH equ 40
+ROOM_PATHS_HEIGHT equ 24
+DECODED_PATHS_WIDTH equ 42
+DECODED_PATHS_HEIGHT equ 26
+
WRITE_BUFFER_SIZE equ 0f010h
FILE_BUFFER_SIZE equ 0600h
ENTRY_READ_BUFFER equ 80h
@@ -296,8 +301,8 @@
FACING2_LEFT equ 1
FACING2_RIGHT equ 2
-FACING2_DOWN equ 3
FACING2_UP equ 4
+FACING2_DOWN equ 8
; Movement record constants
MOVEMENT_FRAME_NUM equ 0
@@ -330,6 +335,21 @@
CHAR_ACTION_PROCESSING_PATH equ 4
CHAR_ACTION_CONTINUE_WALK equ 5
+PATHFIND_CHARACTER_ID equ 2
+PATHFIND_HS4C equ 4
+PATHFIND_DEST_STATE equ 5
+PATHFIND_DEST_X equ 6
+PATHFIND_DEST_Y equ 8
+PATHFIND_X equ 0Ch
+PATHFIND_Y equ 0Ah
+PATHFIND_0E equ 0Eh
+PATHFIND_DEST_X2 equ 10h
+PATHFIND_DEST_OCCUPIED equ 12h
+PATHFIND_CELL_POPULATED equ 13h
+PATHFIND_X_CHANGE1 equ 14h
+PATHFIND_Y_CHANGE1 equ 16h
+PATHFIND_X_CHANGE2 equ 18h
+PATHFIND_Y_CHANGE2 equ 1Ah
; The following equates show data references outside the range of the program.
@@ -11422,24 +11442,9 @@
; ax=character Hotspot Id, bx=dest x, cx=dest y, dl=[4ch]
;\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC
-3983h/4227h = record
- 2 = ax hotspot Id
- 4 = HS[4Ch]
- 6 = dest x
- 8 = dest y
-end;
-
-TEMP_CHARACTER_ID equ 2
-TEMP_HS4C equ 04h
-TEMP_DEST_X equ 06h
-TEMP_DEST_Y equ 08h
-TEMP_X equ 0Ch
-TEMP_Y equ 0Ah
-TEMP_DEST_X2 equ 10h
-
character_pathfind proc near
273F:49F6 89 26 3942 mov pathfind_sp, sp ; Backup current SP
-273F:49FA C7 06 3944 0FA0 mov pathfind_v2, 0FA0h
+273F:49FA C7 06 3944 0FA0 mov pathfind_countdown_ctr, 0FA0h
273F:4A00 F6 06 3946 FF test pathfind_in_progress, 0FFh
273F:4A05 74 0E jz loc_933 ; Jump if zero
273F:4A07 3D 03E8 cmp ax, PLAYER_HOTSPOT_ID
@@ -11469,8 +11474,8 @@
273F:4A37 loc_935: ; xref 273F:4A1E
273F:4A37 C6 06 3946 01 mov pathfind_in_progress, 1
273F:4A3C loc_936: ; xref 273F:4A2A
-273F:4A3C 88 54 04 mov [si+TEMP_HS4C], dl ; Store HS[4Ch]
-273F:4A3F 89 44 02 mov [si+TEMP_CHARACTER_ID], ax ; Store character Id
+273F:4A3C 88 54 04 mov [si+PATHFIND_HS4C], dl
+273F:4A3F 89 44 02 mov [si+PATHFIND_CHARACTER_ID], ax ; Store character Id
273F:4A42 8B E5 mov sp, bp
; Handle adjusting destination X for left & right screen edges to place it completely
@@ -11484,8 +11489,8 @@
273F:4A53 72 03 jb loc_938 ; Jump if below
273F:4A55 83 C3 32 add bx, 50
273F:4A58 loc_938:
-273F:4A58 89 5C 06 mov [si+TEMP_DEST_X], bx ; Store X
-273F:4A5B 89 4C 08 mov [si+TEMP_DEST_Y], cx ; Store Y
+273F:4A58 89 5C 06 mov [si+PATHFIND_DEST_X], bx ; Store X
+273F:4A5B 89 4C 08 mov [si+PATHFIND_DEST_Y], cx ; Store Y
273F:4A5E 8B 6D 13 mov bp, [di+ANIM_WIDTH_COPY]
273F:4A61 83 ED 01 sub bp, 1
@@ -11493,6 +11498,8 @@
273F:4A66 D3 ED shr bp, cl ; bp=(width copy-1)/8
273F:4A68 57 push di
273F:4A69 \xFA81 C6 08A2 add si, 8A2h
+
+; Figure out the address for the bit-compressed data for screen walkable areas
273F:4A6D 8B 45 0E mov ax, [di+ANIM_ROOM_NUM]
273F:4A70 8B D8 mov bx, ax
273F:4A72 B1 04 mov cl, 4
@@ -11500,6 +11507,12 @@
273F:4A76 2B C3 sub ax, bx
273F:4A78 B1 03 mov cl, 3
273F:4A7A D3 E0 shl ax, cl ; ax=Room # * 120
+
+; Extract the bit-compressed data of the pathfinding data for the room into an
+; uncompressed 26*42 byte array indicating whether each 8x8 pixel block on screen
+; (and a surrounding column and row around the screen edge) can be traveled on
+; cx = bit number, dl = number of columns, dh = number of rows
+
273F:4A7C 05 9849 add ax, offset pathfind_data2 - 1
273F:4A7F 1E push ds
273F:4A80 07 pop es
@@ -11507,26 +11520,22 @@
273F:4A83 8B F0 mov si, ax ; si=end of pathfind layer for room
273F:4A85 FD std ; Set for reverse direction
273F:4A86 33 C0 xor ax, ax
-273F:4A88 B9 002B mov cx, 2Bh
+273F:4A88 B9 002B mov cx, 2Bh ; # cols + start col of row #2
273F:4A8B F3/ AB rep stosw ; Clear area
273F:4A8D 83 C7 01 add di, 1 ; For player di=41D0h
-; Extract the bit-compressed data of the pathfinding data for the room into an
-; uncompressed array indicating whether each 8x8 pixel block can be traveled on
-; cx = bit number, dl = number of columns, dh = number of rows
-
-273F:4A90 B6 18 mov dh, 18h
+273F:4A90 B6 18 mov dh, 24 ; Number of rows on-screen
273F:4A92 loc_939:
-273F:4A92 B2 05 mov dl, 5
+273F:4A92 B2 05 mov dl, 5 ; Number of bytes horizontally
273F:4A94 loc_940:
-273F:4A94 AC lodsb ; ax=c6h, si=98c0h
-273F:4A95 86 E0 xchg ah, al
-273F:4A97 32 C0 xor al, al ; ax=c600h
-273F:4A99 B9 0008 mov cx, 8
+273F:4A94 AC lodsb ; Get next byte
+273F:4A95 86 E0 xchg ah, al ; Move it into AH
+273F:4A97 32 C0 xor al, al ; Reset AL to 0 for storage
+273F:4A99 B9 0008 mov cx, 8 ; Number of bits in the byte
273F:4A9C locloop_941: ; xref 273F:4AA2, 4AB3
-273F:4A9C D0 EC shr ah, 1 ; Shift w/zeros fill
+273F:4A9C D0 EC shr ah, 1 ; Move next bit for processing
273F:4A9E 72 06 jc loc_942 ; Jump if bit set (block occupied)
273F:4AA0 AA stosb ; Store 0 to es:[di]
273F:4AA1 AA stosb ; Store 0 to es:[di]
@@ -11579,25 +11588,26 @@
273F:4AE5 80 EE 01 sub dh, 1
273F:4AE8 75 A8 jnz loc_939 ; Jump if not zero
-; End of decompression code for the path finding layer
273F:4AEA 83 EF 01 sub di, 1
-273F:4AED B9 0029 mov cx, 29h
-273F:4AF0 33 C0 xor ax, ax ; Zero register
-273F:4AF2 F3/ AB rep stosw ; Rep when cx >0 Store ax to es:[di]
-273F:4AF4 83 EF 1A sub di, 1Ah ; di=3983 again
+273F:4AED B9 0029 mov cx, 29h ; Handle final off-screen row
+273F:4AF0 33 C0 xor ax, ax
+273F:4AF2 F3/ AB rep stosw
+; End of decompression code for the path finding layer.
+
+273F:4AF4 83 EF 1A sub di, 1Ah ; di=3983 again (skips local variables)
273F:4AF7 5E pop si ; si=anim slot
273F:4AF8 33 C0 xor ax, ax ; Zero register
-273F:4AFA 89 45 0A mov [di+0Ah], ax
-273F:4AFD 89 45 0C mov [di+0Ch], ax
-273F:4B00 89 45 10 mov [di+10h], ax
-273F:4B03 89 45 0E mov [di+0Eh], ax
-273F:4B06 88 45 05 mov [di+5], al
-273F:4B09 81 2E 3944 02BC sub pathfind_v2, 2BCh
+273F:4AFA 89 45 0A mov [di+PATHFIND_Y], ax
+273F:4AFD 89 45 0C mov [di+PATHFIND_X], ax
+273F:4B00 89 45 10 mov [di+PATHFIND_DEST_X2], ax
+273F:4B03 89 45 0E mov [di+PATHFIND_0E], ax
+273F:4B06 88 45 05 mov [di+PATHFIND_DEST_STATE], al
+273F:4B09 81 2E 3944 02BC sub pathfind_countdown_ctr, 2BCh ; v2=0FA0h-2BCh=CE4h
273F:4B0F 8B 04 mov ax, [si+ANIM_X] ; Get current X
273F:4B11 2D 0080 sub ax, 80h ; Subtract the 80h offset
273F:4B14 73 05 jnc loc_950 ; Jump if current X on-screen
-273F:4B16 89 45 0C mov [di+TEMP_X], ax
+273F:4B16 89 45 0C mov [di+PATHFIND_X], ax
273F:4B19 33 C0 xor ax, ax ; Zero register
273F:4B1B loc_950: ; ax = max(0, X)
273F:4B1B BB 013F mov bx, 319
@@ -11605,43 +11615,44 @@
273F:4B21 3B C3 cmp ax, bx
273F:4B23 72 07 jb loc_951 ; X + full width on screen?
273F:4B25 2B C3 sub ax, bx
-273F:4B27 89 45 0C mov [di+TEMP_X], ax ; X = min(X, 319 - width)
+273F:4B27 89 45 0C mov [di+PATHFIND_X], ax ; X = min(X, 319 - width)
273F:4B2A 8B C3 mov ax, bx
273F:4B2C loc_951:
273F:4B2C 8B 5C 02 mov bx, [si+ANIM_Y]
273F:4B2F 80 E3 F8 and bl, 0F8h
273F:4B32 03 5C 15 add bx, [si+ANIM_HEIGHT_COPY]
273F:4B35 83 EB 04 sub bx, 4
-273F:4B38 81 EB 0088 sub bx, 88h
-273F:4B3C 73 05 jnc loc_952 ; Jump if carry=0
-273F:4B3E 89 5D 0A mov [di+TEMP_Y], bx
+273F:4B38 81 EB 0088 sub bx, 88h ; bx=(Y&0F8h+height-4-8)
+273F:4B3C 73 05 jnc loc_952 ; Jump if bx (y bottom) < 0
+273F:4B3E 89 5D 0A mov [di+PATHFIND_Y], bx
273F:4B41 33 DB xor bx, bx ; Zero register
-273F:4B43 loc_952: ; xref 273F:4B3C
-273F:4B43 81 FB 00C0 cmp bx, 192
+273F:4B43 loc_952:
+273F:4B43 81 FB 00C0 cmp bx, 192 ; Is it on-screen?
273F:4B47 72 0A jb loc_953 ; Jump if below
273F:4B49 81 EB 00BF sub bx, 191
-273F:4B4D 89 5D 0A mov [di+TEMP_Y], bx
+273F:4B4D 89 5D 0A mov [di+PATHFIND_Y], bx
273F:4B50 BB 00BF mov bx, 191
-273F:4B53 loc_953: ; xref 273F:4B47
-273F:4B53 8B 4D 06 mov cx, [di+TEMP_DEST_X]
+
+273F:4B53 loc_953:
+273F:4B53 8B 4D 06 mov cx, [di+PATHFIND_DEST_X]
273F:4B56 81 E9 0080 sub cx, 128
273F:4B5A 73 05 jnc loc_954 ; Jump if x >= 0
-273F:4B5C 89 4D 10 mov [di+TEMP_DEST_X2], cx ; Store X (will be negative)
+273F:4B5C 89 4D 10 mov [di+PATHFIND_DEST_X2], cx ; Store X (will be negative)
273F:4B5F 33 C9 xor cx, cx
-273F:4B61 loc_954:
+273F:4B61 loc_954:
273F:4B61 BA 0140 mov dx, 320
273F:4B64 2B 54 13 sub dx, [si+ANIM_WIDTH_COPY]
273F:4B67 3B CA cmp cx, dx
273F:4B69 72 07 jb loc_955 ; Jump if fully on screen
273F:4B6B 2B CA sub cx, dx
-273F:4B6D 89 4D 10 mov [di+TEMP_DEST_X2], cx
+273F:4B6D 89 4D 10 mov [di+PATHFIND_DEST_X2], cx
273F:4B70 8B CA mov cx, dx
-273F:4B72 loc_955: ; xref 273F:4B69
-273F:4B72 8B 55 08 mov dx, [di+TEMP_DEST_Y]
+273F:4B72 loc_955:
+273F:4B72 8B 55 08 mov dx, [di+PATHFIND_DEST_Y]
273F:4B75 81 EA 0088 sub dx, 88h
-273F:4B79 73 02 jnc loc_956 ; Jump if carry=0
+273F:4B79 73 02 jnc loc_956 ; Jump if y >= 0
273F:4B7B 33 D2 xor dx, dx ; Zero register
-273F:4B7D loc_956: ; xref 273F:4B79
+273F:4B7D loc_956:
273F:4B7D 81 FA 00C0 cmp dx, 192
273F:4B81 72 03 jb loc_957 ; Jump if below
273F:4B83 BA 00BF mov dx, 191
@@ -11650,18 +11661,23 @@
; current=(ax,bx), dest=(bp,dx). Check to see if a move of only a few pixels is required
273F:4B88 B1 03 mov cl, 3
-273F:4B8A D3 E8 shr ax, cl ; Shift w/zeros fill
-273F:4B8C D3 EB shr bx, cl ; Shift w/zeros fill
-273F:4B8E D3 ED shr bp, cl ; Shift w/zeros fill
-273F:4B90 D3 EA shr dx, cl ; Shift w/zeros fill
-273F:4B92 3B C5 cmp ax, bp
-273F:4B94 75 2B jne loc_961 ; Jump if not equal
-273F:4B96 3B DA cmp bx, dx
-273F:4B98 75 27 jne loc_961 ; Jump if not equal
+273F:4B8A D3 E8 shr ax, cl
+273F:4B8C D3 EB shr bx, cl
+273F:4B8E D3 ED shr bp, cl
+273F:4B90 D3 EA shr dx, cl
+273F:4B92 3B C5 cmp ax, bp ; Is x/8=dest_x/8?
+273F:4B94 75 2B jne loc_961 ; Jump if not
+273F:4B96 3B DA cmp bx, dx ; Is y/8=dest_y/8?
+273F:4B98 75 27 jne loc_961 ; Jump if not
+; Destination is very close to source.
+; If (I think) the PATHFIND_DEST_X2 != 0 (ie. dest is partially off-screen), then
+; an initial walk entry is placed. Then irrespective, control jumps to loc_1003,
+; which puts another left/right walking entry to move the character to dest X
+
273F:4B9A \xFABB 3940 mov bx, offset pathfind_buffer_end
273F:4B9D C7 07 0000 mov word ptr [bx], 0 ; Set end of pathfind sequence
-273F:4BA1 8B 45 10 mov ax, [di+TEMP_DEST_X2]
+273F:4BA1 8B 45 10 mov ax, [di+PATHFIND_DEST_X2]
273F:4BA4 0B C0 or ax, ax ; Any partial off-screen move?
273F:4BA6 74 16 jz loc_960 ; Jump if zero
273F:4BA8 78 07 js loc_958 ; Jump if sign=1
@@ -11675,80 +11691,87 @@
273F:4BBB 83 EB 04 sub bx, 4 ; Move back for next record
273F:4BBE loc_960:
273F:4BBE E9 02B3 jmp loc_1003
+
+; Destination isn't close, so here's where the actual pathfinding needs to be done
+; current=(ax,bx)/8, dest=(bp,dx)/8
+
273F:4BC1 loc_961: ; xref 273F:4B94, 4B98
273F:4BC1 50 push ax
273F:4BC2 53 push bx
273F:4BC3 55 push bp
273F:4BC4 52 push dx
-273F:4BC5 89 6D 06 mov [di+6],bp
-273F:4BC8 89 55 08 mov [di+8],dx
-273F:4BCB D1 E0 shl ax,1 ; Shift w/zeros fill
-273F:4BCD 8B F3 mov si,bx
-273F:4BCF B1 02 mov cl,2
-273F:4BD1 D3 E3 shl bx,cl ; Shift w/zeros fill
-273F:4BD3 03 DE add bx,si
-273F:4BD5 D3 E3 shl bx,cl ; Shift w/zeros fill
-273F:4BD7 03 DE add bx,si
-273F:4BD9 D3 E3 shl bx,cl ; Shift w/zeros fill
-273F:4BDB 03 D8 add bx,ax
-273F:4BDD 83 C3 72 add bx,72h
-273F:4BE0 03 DF add bx,di
-273F:4BE2 C7 07 0001 mov word ptr [bx],1
-273F:4BE6 D1 E5 shl bp,1 ; Shift w/zeros fill
-273F:4BE8 8B F2 mov si,dx
-273F:4BEA D3 E6 shl si,cl ; Shift w/zeros fill
-273F:4BEC 03 F2 add si,dx
-273F:4BEE D3 E6 shl si,cl ; Shift w/zeros fill
-273F:4BF0 03 F2 add si,dx
-273F:4BF2 D3 E6 shl si,cl ; Shift w/zeros fill
-273F:4BF4 03 F5 add si,bp
-273F:4BF6 83 C6 72 add si,72h
-273F:4BF9 03 F7 add si,di
-273F:4BFB C6 45 12 00 mov byte ptr [di+12h],0
-273F:4BFF F6 04 FF test byte ptr [si],0FFh
-273F:4C02 74 0C jz loc_962 ; Jump if zero
-273F:4C04 C7 04 0000 mov word ptr [si],0
-273F:4C08 C6 45 12 01 mov byte ptr [di+12h],1
-273F:4C0C C6 45 05 01 mov byte ptr [di+5],1
-273F:4C10 loc_962: ; xref 273F:4C02
-273F:4C10 F6 45 04 FF test byte ptr [di+4],0FFh
-273F:4C14 74 00 jz $+2 ; delay for I/O
+273F:4BC5 89 6D 06 mov [di+PATHFIND_DEST_X], bp ; Store dest pos/8
+273F:4BC8 89 55 08 mov [di+PATHFIND_DEST_Y], dx
+
+273F:4BCB D1 E0 shl ax, 1 ; ax=sb_x*2
+273F:4BCD 8B F3 mov si, bx ; si=sb_y
+273F:4BCF B1 02 mov cl, 2
+273F:4BD1 D3 E3 shl bx, cl ; bx=sb_y*4
+273F:4BD3 03 DE add bx, si ; bx=sb_y*5
+273F:4BD5 D3 E3 shl bx, cl ; bx=sb_y*20
+273F:4BD7 03 DE add bx, si ; bx=sb_y*21
+273F:4BD9 D3 E3 shl bx, cl ; bx=sb_y*84
+273F:4BDB 03 D8 add bx, ax ; bx=sb_y*84 + sb_x*2
+273F:4BDD 83 C3 72 add bx, 72h ; Add on buffer & blank line offset
+273F:4BE0 03 DF add bx, di ; bx=source cell
+273F:4BE2 C7 07 0001 mov word ptr [bx],1 ; Flag source cell
+273F:4BE6 D1 E5 shl bp, 1
+273F:4BE8 8B F2 mov si, dx
+273F:4BEA D3 E6 shl si, cl
+273F:4BEC 03 F2 add si, dx
+273F:4BEE D3 E6 shl si, cl
+273F:4BF0 03 F2 add si, dx
+273F:4BF2 D3 E6 shl si, cl
+273F:4BF4 03 F5 add si, bp
+273F:4BF6 83 C6 72 add si, 72h
+273F:4BF9 03 F7 add si, di ; si=dest cell
+273F:4BFB C6 45 12 00 mov byte ptr [di+PATHFIND_DEST_OCCUPIED], 0
+273F:4BFF F6 04 FF test byte ptr [si], 0FFh ; Is dest cell blocked?
+273F:4C02 74 0C jz loc_962 ; Jump if clear
+273F:4C04 C7 04 0000 mov word ptr [si], 0 ; Mark dest cell as unblocked
+273F:4C08 C6 45 12 01 mov byte ptr [di+PATHFIND_DEST_OCCUPIED], 1
+273F:4C0C C6 45 05 01 mov byte ptr [di+PATHFIND_DEST_STATE], 1 ; Dest occupied
+273F:4C10 loc_962:
+273F:4C10 F6 45 04 FF test byte ptr [di+PATHFIND_HS4C],0FFh
+273F:4C14 74 00 jz $+2
273F:4C16 5A pop dx
273F:4C17 59 pop cx
273F:4C18 5D pop bp
273F:4C19 58 pop ax
-273F:4C1A 3B C1 cmp ax,cx
-273F:4C1C 73 19 jae loc_964 ; Jump if above or =
-273F:4C1E 0B C0 or ax,ax ; Zero ?
-273F:4C20 74 06 jz loc_963 ; Jump if zero
-273F:4C22 2D 0001 sub ax,1
-273F:4C25 83 EB 02 sub bx,2
-273F:4C28 loc_963: ; xref 273F:4C20
-273F:4C28 C7 45 14 0002 mov word ptr [di+14h],2
-273F:4C2D B9 0028 mov cx,28h
-273F:4C30 2B C8 sub cx,ax
-273F:4C32 89 4D 18 mov [di+18h],cx
+
+; Source/8=(ax,bp), Dest/8=(cx,dx), si=source cell, bx=dest cell
+273F:4C1A 3B C1 cmp ax,cx ; Start X against Dest X
+273F:4C1C 73 19 jae loc_964 ; Jump if >=
+273F:4C1E 0B C0 or ax,ax ; Is Start X 0?
+273F:4C20 74 06 jz loc_963 ; Jump if yes
+273F:4C22 2D 0001 sub ax, 1
+273F:4C25 83 EB 02 sub bx, 2
+273F:4C28 loc_963:
+273F:4C28 C7 45 14 0002 mov word ptr [di+PATHFIND_X_CHANGE1], 2
+273F:4C2D B9 0028 mov cx, 28h
+273F:4C30 2B C8 sub cx, ax
+273F:4C32 89 4D 18 mov [di+PATHFIND_X_CHANGE2], cx
273F:4C35 EB 17 jmp short loc_966 ; (4C4E)
273F:4C37 loc_964: ; xref 273F:4C1C
-273F:4C37 3D 0027 cmp ax,27h
+273F:4C37 3D 0027 cmp ax, 27h
273F:4C3A 74 06 je loc_965 ; Jump if equal
-273F:4C3C 05 0001 add ax,1
-273F:4C3F 83 C3 02 add bx,2
+273F:4C3C 05 0001 add ax, 1
+273F:4C3F 83 C3 02 add bx, 2
273F:4C42 loc_965: ; xref 273F:4C3A
-273F:4C42 C7 45 14 FFFE mov word ptr [di+14h],0FFFEh
-273F:4C47 89 45 18 mov [di+18h],ax
-273F:4C4A 83 45 18 01 add word ptr [di+18h],1
+273F:4C42 C7 45 14 FFFE mov word ptr [di+PATHFIND_X_CHANGE1], 0FFFEh
+273F:4C47 89 45 18 mov [di+PATHFIND_X_CHANGE2],ax
+273F:4C4A 83 45 18 01 add word ptr [di+PATHFIND_X_CHANGE2], 1
273F:4C4E loc_966: ; xref 273F:4C35
-273F:4C4E 3B EA cmp bp,dx
+273F:4C4E 3B EA cmp bp, dx
273F:4C50 72 19 jb loc_968 ; Jump if below
-273F:4C52 83 FD 17 cmp bp,17h
+273F:4C52 83 FD 17 cmp bp, 17h
273F:4C55 74 06 je loc_967 ; Jump if equal
-273F:4C57 83 C5 01 add bp,1
-273F:4C5A 83 C3 54 add bx,54h
+273F:4C57 83 C5 01 add bp, 1
+273F:4C5A 83 C3 54 add bx, DECODED_PATHS_WIDTH * 2
273F:4C5D loc_967: ; xref 273F:4C55
-273F:4C5D C7 45 16 FFAC mov word ptr [di+16h],0FFACh
-273F:4C62 89 6D 1A mov [di+1Ah],bp
-273F:4C65 83 45 1A 01 add word ptr [di+1Ah],1
+273F:4C5D C7 45 16 FFAC mov [di+PATHFIND_Y_CHANGE1], -DECODED_PATHS_WIDTH*2
+273F:4C62 89 6D 1A mov [di+PATHFIND_Y_CHANGE2], bp
+273F:4C65 83 45 1A 01 add [di+PATHFIND_Y_CHANGE2], 1
273F:4C69 EB 17 jmp short loc_970 ; (4C82)
273F:4C6B loc_968: ; xref 273F:4C50
273F:4C6B 0B ED or bp,bp ; Zero ?
@@ -11756,159 +11779,179 @@
273F:4C6F 83 ED 01 sub bp,1
273F:4C72 83 EB 54 sub bx,54h
273F:4C75 loc_969: ; xref 273F:4C6D
-273F:4C75 C7 45 16 0054 mov word ptr [di+16h],54h
+273F:4C75 C7 45 16 0054 mov word ptr [di+PATHFIND_Y_CHANGE1], DECODED_PATHS_WIDTH * 2
273F:4C7A B9 0018 mov cx,18h
273F:4C7D 2B CD sub cx,bp
-273F:4C7F 89 4D 1A mov [di+1Ah],cx
-273F:4C82 loc_970: ; xref 273F:4C69
-273F:4C82 8B 55 14 mov dx,[di+14h]
+273F:4C7F 89 4D 1A mov [di+PATHFIND_Y_CHANGE2], cx
+273F:4C82 loc_970:
+
+; This next section populates the walkable sections of the decompressed array
+; with incrementing numbers indicating the number of cells away each cell is
+; from the destination. A walkable path can be later formed by following the
+; path of decrementing numbers from the source to the destination
+
+273F:4C82 8B 55 14 mov dx,[di+PATHFIND_X_CHANGE1]
273F:4C85 loc_971: ; xref 273F:4CC6, 4CCE, 4CDA
273F:4C85 \xFA56 push si
273F:4C86 53 push bx
-273F:4C87 8B 36 3944 mov si, pathfind_v2
-273F:4C8B 8B 4D 1A mov cx, [di+1Ah]
+273F:4C87 8B 36 3944 mov si, pathfind_countdown_ctr
+273F:4C8B 8B 4D 1A mov cx, [di+PATHFIND_Y_CHANGE2]
273F:4C8E locloop_972: ; xref 273F:4C9F
273F:4C8E 51 push cx
273F:4C8F 53 push bx
-273F:4C90 8B 4D 18 mov cx, [di+18h]
+273F:4C90 8B 4D 18 mov cx, [di+PATHFIND_X_CHANGE2]
273F:4C93 locloop_973: ; xref 273F:4C98
-273F:4C93 E8 021A call sub_120 ; (4EB0)
-273F:4C96 03 DA add bx,dx
+273F:4C93 E8 021A call pathfind_populate_cells
+273F:4C96 03 DA add bx, dx
273F:4C98 E2 F9 loop locloop_973 ; Loop if cx > 0
273F:4C9A 5B pop bx
273F:4C9B 59 pop cx
-273F:4C9C 03 5D 16 add bx,[di+16h]
+273F:4C9C 03 5D 16 add bx, [di+PATHFIND_Y_CHANGE1]
273F:4C9F E2 ED loop locloop_972 ; Loop if cx > 0
-273F:4CA1 89 36 3944 mov pathfind_v2, si
+273F:4CA1 89 36 3944 mov pathfind_countdown_ctr, si
273F:4CA5 5B pop bx
273F:4CA6 5E pop si
-273F:4CA7 F7 04 FFFF test word ptr [si],0FFFFh
-273F:4CAB 75 2F jnz loc_977 ; Jump if not zero
-273F:4CAD 80 7D 1A 18 cmp byte ptr [di+1Ah],18h
+273F:4CA7 F7 04 FFFF test word ptr [si], 0FFFFh ; Dest been filled in yet?
+273F:4CAB 75 2F jnz loc_977 ; Jump if yes
+
+273F:4CAD 80 7D 1A 18 cmp byte ptr [di+PATHFIND_Y_CHANGE2], ROOM_PATHS_HEIGHT
273F:4CB1 75 08 jne loc_974 ; Jump if not equal
-273F:4CB3 80 7D 18 28 cmp byte ptr [di+18h],28h ; '('
+273F:4CB3 80 7D 18 28 cmp byte ptr [di+PATHFIND_X_CHANGE2], ROOM_PATHS_WIDTH
273F:4CB7 74 17 je loc_976 ; Jump if equal
-273F:4CB9 EB 07 jmp short loc_975 ; (4CC2)
+273F:4CB9 EB 07 jmp short loc_975
273F:4CBB loc_974: ; xref 273F:4CB1
-273F:4CBB 2B 5D 16 sub bx,[di+16h]
-273F:4CBE 83 45 1A 01 add word ptr [di+1Ah],1
-273F:4CC2 loc_975: ; xref 273F:4CB9
-273F:4CC2 80 7D 18 28 cmp byte ptr [di+18h],28h ; '('
+273F:4CBB 2B 5D 16 sub bx, [di+PATHFIND_Y_CHANGE1]
+273F:4CBE 83 45 1A 01 add word ptr [di+PATHFIND_Y_CHANGE2], 1
+273F:4CC2 loc_975:
+273F:4CC2 80 7D 18 28 cmp byte ptr [di+PATHFIND_X_CHANGE2], ROOM_PATHS_WIDTH
273F:4CC6 74 BD je loc_971 ; Jump if equal
-273F:4CC8 2B DA sub bx,dx
-273F:4CCA 83 45 18 01 add word ptr [di+18h],1
-273F:4CCE EB B5 jmp short loc_971 ; (4C85)
-273F:4CD0 loc_976: ; xref 273F:4CB7
-273F:4CD0 F6 45 13 FF test byte ptr [di+13h],0FFh
-273F:4CD4 74 08 jz loc_978 ; Jump if zero
-273F:4CD6 C6 45 13 00 mov byte ptr [di+13h],0
-273F:4CDA EB A9 jmp short loc_971 ; (4C85)
-273F:4CDC loc_977: ; xref 273F:4CAB
-273F:4CDC EB 66 jmp short loc_982 ; (4D44)
-273F:4CDE loc_978: ; xref 273F:4CD4
-273F:4CDE C6 45 05 02 mov byte ptr [di+5],2
-273F:4CE2 loc_979: ; xref 273F:4D48
-273F:4CE2 F6 45 12 FF test byte ptr [di+12h],0FFh
+273F:4CC8 2B DA sub bx, dx
+273F:4CCA 83 45 18 01 add word ptr [di+PATHFIND_X_CHANGE2], 1
+273F:4CCE EB B5 jmp short loc_971
+
+273F:4CD0 loc_976:
+273F:4CD0 F6 45 13 FF test byte ptr [di+PATHFIND_CELL_POPULATED], 0FFh
+273F:4CD4 74 08 jz loc_978 ; Jump if no cell populated
+273F:4CD6 C6 45 13 00 mov byte ptr [di+PATHFIND_CELL_POPULATED], 0
+273F:4CDA EB A9 jmp short loc_971 ; Jump for another try
+273F:4CDC loc_977:
+273F:4CDC EB 66 jmp short loc_982
+273F:4CDE loc_978:
+273F:4CDE C6 45 05 02 mov byte ptr [di+PATHFIND_DEST_STATE], 2 ; No path to destination
+273F:4CE2 loc_979:
+273F:4CE2 F6 45 12 FF test byte ptr [di+PATHFIND_DEST_OCCUPIED], 0FFh
273F:4CE6 74 08 jz loc_980 ; Jump if zero
-273F:4CE8 C7 04 FFFF mov word ptr [si],0FFFFh
-273F:4CEC C6 45 12 00 mov byte ptr [di+12h],0
-273F:4CF0 loc_980: ; xref 273F:4CE6
+273F:4CE8 C7 04 FFFF mov word ptr [si], 0FFFFh ; Restore destination occupied
+273F:4CEC C6 45 12 00 mov byte ptr [di+PATHFIND_DEST_OCCUPIED], 0
+273F:4CF0 loc_980:
+
+; Do a prescanning of the lines
273F:4CF0 57 push di
-273F:4CF1 8B EE mov bp,si
-273F:4CF3 8B DE mov bx,si
-273F:4CF5 B2 FF mov dl,0FFh
-273F:4CF7 8B 4D 06 mov cx,[di+6]
-273F:4CFA 83 C1 01 add cx,1
-273F:4CFD BF FFFE mov di,0FFFEh
-273F:4D00 E8 0220 call sub_121 ; (4F23)
+273F:4CF1 8B EE mov bp, si
+273F:4CF3 8B DE mov bx, si ; bx=bp=destination cell
+273F:4CF5 B2 FF mov dl, 0FFh
+273F:4CF7 8B 4D 06 mov cx, [di+PATHFIND_DEST_X]
+273F:4CFA 83 C1 01 add cx, 1
+273F:4CFD BF FFFE mov di, 0FFFEh
+273F:4D00 E8 0220 call pathfind_scan_line
273F:4D03 5F pop di
273F:4D04 57 push di
-273F:4D05 B9 0028 mov cx,28h
-273F:4D08 2B 4D 06 sub cx,[di+6]
-273F:4D0B BF 0002 mov di,2
-273F:4D0E E8 0212 call sub_121 ; (4F23)
+273F:4D05 B9 0028 mov cx, ROOM_PATHS_WIDTH
+273F:4D08 2B 4D 06 sub cx, [di+PATHFIND_DEST_X]
+273F:4D0B BF 0002 mov di, 2
+273F:4D0E E8 0212 call pathfind_scan_line
273F:4D11 5F pop di
273F:4D12 57 push di
-273F:4D13 8B 4D 08 mov cx,[di+8]
-273F:4D16 83 C1 01 add cx,1
-273F:4D19 BF FFAC mov di,0FFACh
-273F:4D1C E8 0204 call sub_121 ; (4F23)
+273F:4D13 8B 4D 08 mov cx, [di+PATHFIND_DEST_Y]
+273F:4D16 83 C1 01 add cx, 1
+273F:4D19 BF FFAC mov di, -DECODED_PATHS_WIDTH*2
+273F:4D1C E8 0204 call pathfind_scan_line
273F:4D1F 5F pop di
273F:4D20 57 push di
-273F:4D21 B9 0018 mov cx,18h
-273F:4D24 2B 4D 08 sub cx,[di+8]
-273F:4D27 BF 0054 mov di,54h
-273F:4D2A E8 01F6 call sub_121 ; (4F23)
+273F:4D21 B9 0018 mov cx, ROOM_PATHS_HEIGHT
+273F:4D24 2B 4D 08 sub cx, [di+PATHFIND_DEST_Y]
+273F:4D27 BF 0054 mov di, DECODED_PATHS_WIDTH*2
+273F:4D2A E8 01F6 call pathfind_scan_line
273F:4D2D 5F pop di
-273F:4D2E 8B F5 mov si,bp
-273F:4D30 3B DE cmp bx,si
+273F:4D2E 8B F5 mov si, bp
+273F:4D30 3B DE cmp bx, si
273F:4D32 75 0E jne loc_981 ; Jump if not equal
-273F:4D34 C6 45 05 03 mov byte ptr [di+5],3
-273F:4D38 \xFABB 3940 mov bx,3940h ; (273F:3940=0C7h)
-273F:4D3B C7 07 0000 mov word ptr [bx],0
+273F:4D34 C6 45 05 03 mov byte ptr [di+PATHFIND_DEST_STATE], 3
+273F:4D38 \xFABB 3940 mov bx, offset pathfind_buffer_end
+273F:4D3B C7 07 0000 mov word ptr [bx], 0
273F:4D3F E9 0132 jmp loc_1003 ; (4E74)
273F:4D42 loc_981: ; xref 273F:4D32
-273F:4D42 8B F3 mov si,bx
+273F:4D42 8B F3 mov si, bx
+
273F:4D44 loc_982: ; xref 273F:4CDC
-273F:4D44 F6 45 12 FF test byte ptr [di+12h],0FFh
+273F:4D44 F6 45 12 FF test byte ptr [di+PATHFIND_DEST_OCCUPIED], 0FFh
273F:4D48 75 98 jnz loc_979 ; Jump if not zero
+
+; end of cell population
+; Fill out any cells that are still blank (ie. anywhere that can't reach the
+; destination) as occupied
+
273F:4D4A FC cld ; Clear direction
273F:4D4B 57 push di
-273F:4D4C 83 C7 1C add di,1Ch
-273F:4D4F B9 0445 mov cx,445h
-273F:4D52 33 C0 xor ax,ax ; Zero register
-273F:4D54 loc_983: ; xref 273F:4D5F
-273F:4D54 \xFAF2/ AF repne scasw ; Rep zf=0+cx >0 Scan es:[di] for ax
-273F:4D56 0B C9 or cx,cx ; Zero ?
-273F:4D58 74 07 jz loc_984 ; Jump if zero
-273F:4D5A C7 45 FE FFFF mov word ptr [di-2],0FFFFh
-273F:4D5F EB F3 jmp short loc_983 ; (4D54)
-273F:4D61 loc_984: ; xref 273F:4D58
+273F:4D4C 83 C7 1C add di, 1Ch ; di=start of grid
+273F:4D4F B9 0445 mov cx, DECODED_PATHS_WIDTH*DECODED_PATHS_HEIGHT+1 ;445h
+273F:4D52 33 C0 xor ax, ax
+273F:4D54 loc_983:
+273F:4D54 \xFAF2/ AF repne scasw ; Scan for an empty cell
+273F:4D56 0B C9 or cx, cx ; Reached end of list?
+273F:4D58 74 07 jz loc_984 ; Jump if yes
+273F:4D5A C7 45 FE FFFF mov word ptr [di-2], 0FFFFh ; Replace it with occupied state
+273F:4D5F EB F3 jmp short loc_983
+
+273F:4D61 loc_984:
273F:4D61 5F pop di
-273F:4D62 33 D2 xor dx,dx ; Zero register
+273F:4D62 33 D2 xor dx, dx
273F:4D64 B1 FF mov cl,0FFh
-273F:4D66 \xFABB 3940 mov bx,3940h ; (273F:3940=0C7h)
-273F:4D69 C7 07 0000 mov word ptr [bx],0
-273F:4D6D F6 45 05 FF test byte ptr [di+5],0FFh
+273F:4D66 \xFABB 3940 mov bx, offset pathfind_buffer_end
+273F:4D69 C7 07 0000 mov word ptr [bx], 0
+273F:4D6D F6 45 05 FF test byte ptr [di+PATHFIND_DEST_STATE], 0FFh
273F:4D71 75 1D jnz loc_987 ; Jump if not zero
-273F:4D73 8B 45 10 mov ax,[di+10h]
+273F:4D73 8B 45 10 mov ax, [di+PATHFIND_DEST_X2]
273F:4D76 0B C0 or ax,ax ; Zero ?
273F:4D78 74 16 jz loc_987 ; Jump if zero
273F:4D7A 78 07 js loc_985 ; Jump if sign=1
-273F:4D7C C7 47 FE 0002 mov word ptr [bx-2],2
+273F:4D7C C7 47 FE 0002 mov word ptr [bx-2], FACING2_RIGHT
273F:4D81 EB 07 jmp short loc_986 ; (4D8A)
273F:4D83 loc_985: ; xref 273F:4D7A
-273F:4D83 C7 47 FE 0001 mov word ptr [bx-2],1
+273F:4D83 C7 47 FE 0001 mov word ptr [bx-2], FACING2_LEFT
273F:4D88 F7 D8 neg ax
273F:4D8A loc_986: ; xref 273F:4D81
-273F:4D8A 89 47 FC mov [bx-4],ax
-273F:4D8D 83 EB 04 sub bx,4
+273F:4D8A 89 47 FC mov [bx-4], ax ; Save # steps
+273F:4D8D 83 EB 04 sub bx, 4
273F:4D90 loc_987: ; xref 273F:4D71, 4D78, 4E64, 4E6F
+
273F:4D90 \xFA53 push bx
273F:4D91 56 push si
-273F:4D92 loc_988: ; xref 273F:4DE1, 4E06, 4E2B, 4E4F
-273F:4D92 \xFA8B 04 mov ax,[si]
-273F:4D94 2D 0001 sub ax,1
+
+; Form a set of steps starting at the source
+273F:4D92 loc_988:
+273F:4D92 \xFA8B 04 mov ax, [si] ; Get steps value from current pos
+273F:4D94 2D 0001 sub ax, 1
273F:4D97 74 4A jz loc_992 ; Jump if zero
-273F:4D99 F6 C2 26 test dl,26h ; '&'
+273F:4D99 F6 C2 26 test dl, 38
273F:4D9C 75 11 jnz loc_989 ; Jump if not zero
-273F:4D9E 39 44 AC cmp [si-54h],ax
+273F:4D9E 39 44 AC cmp [si-DECODED_PATHS_WIDTH*2], ax
273F:4DA1 74 67 je loc_996 ; Jump if equal
-273F:4DA3 39 44 54 cmp [si+HS_DEST_X], ax
+273F:4DA3 39 44 54 cmp [si+DECODED_PATHS_WIDTH*2], ax
273F:4DA6 74 60 je loc_995 ; Jump if equal
-273F:4DA8 39 44 02 cmp [si+2],ax
+273F:4DA8 39 44 02 cmp [si+2], ax
273F:4DAB 74 38 je loc_993 ; Jump if equal
273F:4DAD EB 11 jmp short loc_990 ; (4DC0)
273F:4DAF loc_989: ; xref 273F:4D9C
-273F:4DAF 39 44 02 cmp [si+2],ax
+273F:4DAF 39 44 02 cmp [si+2], ax
273F:4DB2 74 31 je loc_993 ; Jump if equal
-273F:4DB4 39 44 FE cmp [si-2],ax
+273F:4DB4 39 44 FE cmp [si-2], ax
273F:4DB7 74 07 je loc_990 ; Jump if equal
-273F:4DB9 39 44 54 cmp [si+HS_DEST_X], ax
+273F:4DB9 39 44 54 cmp [si+DECODED_PATHS_WIDTH*2], ax
273F:4DBC 74 70 je loc_998 ; Jump if equal
273F:4DBE EB 4A jmp short loc_996 ; (4E0A)
273F:4DC0 loc_990: ; xref 273F:4DAD, 4DB7
@@ -11916,9 +11959,9 @@
273F:4DC3 F6 C2 02 test dl,2
273F:4DC6 75 10 jnz loc_991 ; Jump if not zero
273F:4DC8 80 C6 01 add dh,1
-273F:4DCB C7 47 FE 0002 mov word ptr [bx-2],2
-273F:4DD0 C7 47 FC 0000 mov word ptr [bx-4],0
-273F:4DD5 83 EB 04 sub bx,4
+273F:4DCB C7 47 FE 0002 mov word ptr [bx-2], FACING2_RIGHT
+273F:4DD0 C7 47 FC 0000 mov word ptr [bx-4], 0
+273F:4DD5 83 EB 04 sub bx, 4
273F:4DD8 loc_991: ; xref 273F:4DC6
273F:4DD8 83 EE 02 sub si,2
273F:4DDB 83 07 08 add word ptr [bx],8
@@ -11931,13 +11974,13 @@
273F:4DE8 F6 C2 04 test dl,4
273F:4DEB 75 10 jnz loc_994 ; Jump if not zero
273F:4DED 80 C6 01 add dh,1
-273F:4DF0 C7 47 FE 0001 mov word ptr [bx-2],1
-273F:4DF5 C7 47 FC 0000 mov word ptr [bx-4],0
-273F:4DFA 83 EB 04 sub bx,4
+273F:4DF0 C7 47 FE 0001 mov word ptr [bx-2], FACING2_LEFT
+273F:4DF5 C7 47 FC 0000 mov word ptr [bx-4], 0
+273F:4DFA 83 EB 04 sub bx, 4
273F:4DFD loc_994: ; xref 273F:4DEB
-273F:4DFD 83 C6 02 add si,2
-273F:4E00 83 07 08 add word ptr [bx],8
-273F:4E03 80 CA 04 or dl,4
+273F:4DFD 83 C6 02 add si, 2
+273F:4E00 83 07 08 add word ptr [bx], 8 ; Add # steps
+273F:4E03 80 CA 04 or dl, 4
273F:4E06 EB 8A jmp short loc_988 ; (4D92)
273F:4E08 loc_995: ; xref 273F:4DA6
273F:4E08 EB 24 jmp short loc_998 ; (4E2E)
@@ -11946,52 +11989,58 @@
273F:4E0D F6 C2 08 test dl,8
273F:4E10 75 10 jnz loc_997 ; Jump if not zero
273F:4E12 80 C6 01 add dh,1
-273F:4E15 C7 47 FE 0008 mov word ptr [bx-2],8
-273F:4E1A C7 47 FC 0000 mov word ptr [bx-4],0
-273F:4E1F 83 EB 04 sub bx,4
+273F:4E15 C7 47 FE 0008 mov word ptr [bx-2], FACING2_DOWN
+273F:4E1A C7 47 FC 0000 mov word ptr [bx-4], 0
+273F:4E1F 83 EB 04 sub bx, 4
273F:4E22 loc_997: ; xref 273F:4E10
-273F:4E22 83 EE 54 sub si,54h
-273F:4E25 83 07 08 add word ptr [bx],8
-273F:4E28 80 CA 08 or dl,8
+273F:4E22 83 EE 54 sub si, DECODED_PATHS_WIDTH*2
+273F:4E25 83 07 08 add word ptr [bx], 8 ; Add # steps
+273F:4E28 80 CA 08 or dl, 8
273F:4E2B E9 FF64 jmp loc_988 ; (4D92)
273F:4E2E loc_998: ; xref 273F:4DBC, 4E08
273F:4E2E 80 E2 11 and dl,11h
273F:4E31 F6 C2 10 test dl,10h
273F:4E34 75 10 jnz loc_999 ; Jump if not zero
273F:4E36 80 C6 01 add dh,1
-273F:4E39 C7 47 FE 0004 mov word ptr [bx-2],4
-273F:4E3E C7 47 FC 0000 mov word ptr [bx-4],0
-273F:4E43 83 EB 04 sub bx,4
+273F:4E39 C7 47 FE 0004 mov word ptr [bx-2], FACING2_UP
+273F:4E3E C7 47 FC 0000 mov word ptr [bx-4], 0
+273F:4E43 83 EB 04 sub bx, 4
273F:4E46 loc_999: ; xref 273F:4E34
-273F:4E46 83 C6 54 add si,54h
-273F:4E49 83 07 08 add word ptr [bx],8
-273F:4E4C 80 CA 10 or dl,10h
+273F:4E46 83 C6 54 add si, DECODED_PATHS_WIDTH*2
+273F:4E49 83 07 08 add word ptr [bx], 8 ; Add # steps
+273F:4E4C 80 CA 10 or dl, 10h
273F:4E4F E9 FF40 jmp loc_988 ; (4D92)
-273F:4E52 loc_1000: ; xref 273F:4DE3
-273F:4E52 F6 C2 01 test dl,1
-273F:4E55 75 1B jnz loc_1002 ; Jump if not zero
-273F:4E57 F6 C1 80 test cl,80h
+
+; This post-check is used to go through the paths two times - the first two
+; tries the path using standard direction checks, the second using the alternate
+; checks. If the first run through was the shortest, redo the process a third
+; time to get the walking sequence that was obtained the first time
+273F:4E52 loc_1000:
+273F:4E52 F6 C2 01 test dl, 1 ; Test for exit flag
+273F:4E55 75 1B jnz loc_1002 ; Jump if yes
+273F:4E57 F6 C1 80 test cl, 80h
273F:4E5A 74 0B jz loc_1001 ; Jump if zero
273F:4E5C 5E pop si
273F:4E5D 5B pop bx
-273F:4E5E 8A CE mov cl,dh
-273F:4E60 32 F6 xor dh,dh ; Zero register
-273F:4E62 B2 20 mov dl,20h ; ' '
-273F:4E64 E9 FF29 jmp loc_987 ; (4D90)
-273F:4E67 loc_1001: ; xref 273F:4E5A
-273F:4E67 3A CE cmp cl,dh
+273F:4E5E 8A CE mov cl, dh ; Store number of steps
+273F:4E60 32 F6 xor dh, dh ; Reset counter
+273F:4E62 B2 20 mov dl, 20h ; Flag for alt direction check
+273F:4E64 E9 FF29 jmp loc_987 ; Go get directions again
+273F:4E67 loc_1001:
+273F:4E67 3A CE cmp cl, dh
273F:4E69 73 07 jae loc_1002 ; Jump if above or =
273F:4E6B 5E pop si
273F:4E6C 5B pop bx
-273F:4E6D B2 01 mov dl,1
-273F:4E6F E9 FF1E jmp loc_987 ; (4D90)
-273F:4E72 loc_1002: ; xref 273F:4E55, 4E69
+273F:4E6D B2 01 mov dl, 1 ; Flag for exit after retry
+273F:4E6F E9 FF1E jmp loc_987
+
+273F:4E72 loc_1002:
273F:4E72 5E pop si
273F:4E73 58 pop ax
273F:4E74 loc_1003:
273F:4E74 FC cld ; Clear direction
-273F:4E75 8B 45 0C mov ax, [di+TEMP_X]
+273F:4E75 8B 45 0C mov ax, [di+PATHFIND_X]
273F:4E78 A9 FFFF test ax, 0FFFFh ; Check X position
273F:4E7B 74 19 jz loc_1006
273F:4E7D 78 0A js loc_1004 ; Move
@@ -12007,9 +12056,9 @@
273F:4E96 loc_1006: ; End of pathfinding
273F:4E96 C7 05 0000 mov word ptr [di], 0
273F:4E9A 8B 26 3942 mov sp, pathfind_sp
-273F:4E9E C6 06 3946 00 mov pathfind_in_progress, 0
-273F:4EA3 B8 0001 mov ax, 1
-273F:4EA6 02 45 05 add al, [di+5]
+273F:4E9E C6 06 3946 00 mov pathfind_in_progress, 0 ; Reset in-progress flag
+273F:4EA3 B8 0001 mov ax, 1 ; Set return value
+273F:4EA6 02 45 05 add al, [di+PATHFIND_DEST_STATE]
273F:4EA9 50 push ax
273F:4EAA 53 push bx
273F:4EAB 06 push es
@@ -12026,53 +12075,58 @@
; Called from: 273F:4C93
;\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC
-273F:4EB0 sub_120 proc near
-273F:4EB0 F7 07 FFFF test word ptr [bx],0FFFFh
-273F:4EB4 75 48 jnz loc_1013 ; Jump if not zero
-273F:4EB6 BD FFFF mov bp,0FFFFh
-273F:4EB9 8B 47 AC mov ax,[bx-54h]
-273F:4EBC 0B C0 or ax,ax ; Zero ?
-273F:4EBE 74 06 jz loc_1007 ; Jump if zero
-273F:4EC0 3B C5 cmp ax,bp
-273F:4EC2 73 02 jae loc_1007 ; Jump if above or =
-273F:4EC4 8B E8 mov bp,ax
-273F:4EC6 loc_1007: ; xref 273F:4EBE, 4EC2
-273F:4EC6 8B 47 54 mov ax,[bx+HS_DEST_X]
-273F:4EC9 0B C0 or ax,ax ; Zero ?
-273F:4ECB 74 06 jz loc_1008 ; Jump if zero
-273F:4ECD 3B C5 cmp ax,bp
-273F:4ECF 73 02 jae loc_1008 ; Jump if above or =
-273F:4ED1 8B E8 mov bp,ax
-273F:4ED3 loc_1008: ; xref 273F:4ECB, 4ECF
-273F:4ED3 8B 47 FE mov ax,[bx-2]
-273F:4ED6 0B C0 or ax,ax ; Zero ?
-273F:4ED8 74 06 jz loc_1009 ; Jump if zero
-273F:4EDA 3B C5 cmp ax,bp
-273F:4EDC 73 02 jae loc_1009 ; Jump if above or =
-273F:4EDE 8B E8 mov bp,ax
-273F:4EE0 loc_1009: ; xref 273F:4ED8, 4EDC
-273F:4EE0 8B 47 02 mov ax,[bx+2]
-273F:4EE3 0B C0 or ax,ax ; Zero ?
-273F:4EE5 74 06 jz loc_1010 ; Jump if zero
-273F:4EE7 3B C5 cmp ax,bp
-273F:4EE9 73 02 jae loc_1010 ; Jump if above or =
-273F:4EEB 8B E8 mov bp,ax
-273F:4EED loc_1010: ; xref 273F:4EE5, 4EE9
-273F:4EED 83 C5 01 add bp,1
-273F:4EF0 74 06 jz loc_1011 ; Jump if zero
-273F:4EF2 89 2F mov [bx],bp
-273F:4EF4 C6 45 13 01 mov byte ptr [di+13h],1
+ pathfind_populate_cells proc near
+273F:4EB0 F7 07 FFFF test word ptr [bx], 0FFFFh ; Is cell occupied?
+273F:4EB4 75 48 jnz loc_1013 ; Jump if it is
+273F:4EB6 BD FFFF mov bp, 0FFFFh
+273F:4EB9 8B 47 AC mov ax, [bx-(DECODED_PATHS_WIDTH*2)] ; Get cell from one line up
+273F:4EBC 0B C0 or ax, ax ; Is it occupied
+273F:4EBE 74 06 jz loc_1007 ; Jump if not
+273F:4EC0 3B C5 cmp ax, bp ; Is it standard occupied indicator?
+273F:4EC2 73 02 jae loc_1007
+273F:4EC4 8B E8 mov bp,ax ; Store loaded cell value
+273F:4EC6 loc_1007:
+273F:4EC6 8B 47 54 mov ax, [bx+(DECODED_PATHS_WIDTH*2)] ; Get cell from next line
+273F:4EC9 0B C0 or ax, ax ; Is it occupied?
+273F:4ECB 74 06 jz loc_1008 ; Jump if not
+273F:4ECD 3B C5 cmp ax, bp
+273F:4ECF 73 02 jae loc_1008
+273F:4ED1 8B E8 mov bp, ax ; Store loaded cell value
+273F:4ED3 loc_1008:
+273F:4ED3 8B 47 FE mov ax, [bx-2] ; Get cell from left
+273F:4ED6 0B C0 or ax, ax ; Is it occupied?
+273F:4ED8 74 06 jz loc_1009 ; Jump if not
+273F:4EDA 3B C5 cmp ax, bp
+273F:4EDC 73 02 jae loc_1009 ; Store loaded cell value
+273F:4EDE 8B E8 mov bp, ax
+273F:4EE0 loc_1009:
+273F:4EE0 8B 47 02 mov ax, [bx+2] ; Get cell from right
+273F:4EE3 0B C0 or ax, ax ; Is it occupied?
+273F:4EE5 74 06 jz loc_1010 ; Jump if not
+273F:4EE7 3B C5 cmp ax, bp
+273F:4EE9 73 02 jae loc_1010
+273F:4EEB 8B E8 mov bp, ax ; Store loaded cell value
+273F:4EED loc_1010:
+
+; At this point, bp contains the lowest value from the surrounding cells, not
+; counting entries with 0ffff (occupied). Below we will now add 1 to the value
+; and store it in the cell. By repeated calls processing the entire grid, we
+; can figure out a path to the destination by following sequential numbers
+273F:4EED 83 C5 01 add bp, 1
+273F:4EF0 74 06 jz loc_1011 ; If no vals found, skip save
+273F:4EF2 89 2F mov [bx], bp ; Store value
+273F:4EF4 C6 45 13 01 mov byte ptr [di+PATHFIND_CELL_POPULATED], 1
273F:4EF8 loc_1011: ; xref 273F:4EF0
-273F:4EF8 83 EE 03 sub si,3
-273F:4EFB 72 06 jc loc_1014 ; Jump if carry Set
+273F:4EF8 83 EE 03 sub si, 3 ; Decrement countdown ctr
+273F:4EFB 72 06 jc loc_1014 ; Break if countdown ended
273F:4EFD loc_ret_1012: ; xref 273F:4F01
273F:4EFD C3 retn
273F:4EFE loc_1013: ; xref 273F:4EB4
-273F:4EFE 83 EE 01 sub si,1
-273F:4F01 73 FA jnc loc_ret_1012 ; Jump if carry=0
-273F:4F03 loc_1014: ; xref 273F:4EFB
-273F:4F03 89 36 3944 mov pathfind_v2, si
+273F:4EFE 83 EE 01 sub si, 1 ; Decrement countdown ctr
+273F:4F01 73 FA jnc loc_ret_1012 ; Don't break if countdown not ended
+273F:4F03 loc_1014:
+273F:4F03 89 36 3944 mov pathfind_countdown_ctr, si
273F:4F07 50 push ax
273F:4F08 53 push bx
273F:4F09 51 push cx
@@ -12084,7 +12138,7 @@
273F:4F0F 06 push es
273F:4F10 9C pushf
273F:4F11 E8 0034 call pathfind_return_to_sp
-273F:4F14 9D popf
+273F:4F14 9D popf
273F:4F15 07 pop es
273F:4F16 1F pop ds
273F:4F17 5D pop bp
@@ -12094,9 +12148,9 @@
273F:4F1B 59 pop cx
273F:4F1C 5B pop bx
273F:4F1D 58 pop ax
-273F:4F1E 8B 36 3944 mov si, pathfind_v2
+273F:4F1E 8B 36 3944 mov si, pathfind_countdown_ctr
273F:4F22 C3 retn
- sub_120 endp
+ pathfind_populate_cells endp
;\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF
@@ -12105,25 +12159,25 @@
; Called from: 273F:4D00, 4D0E, 4D1C, 4D2A
;\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC\xDC
-273F:4F23 sub_121 proc near
-273F:4F23 8B F5 mov si,bp
-273F:4F25 32 F6 xor dh,dh ; Zero register
+ pathfind_scan_line proc near
+273F:4F23 8B F5 mov si, bp
+273F:4F25 32 F6 xor dh, dh
273F:4F27 locloop_1015: ; xref 273F:4F45
-273F:4F27 03 F7 add si,di
+273F:4F27 03 F7 add si, di ; Add increment amount
273F:4F29 80 C6 01 add dh,1
-273F:4F2C F7 04 FFFF test word ptr [si],0FFFFh
-273F:4F30 74 13 jz loc_1018 ; Jump if zero
-273F:4F32 78 11 js loc_1018 ; Jump if sign=1
-273F:4F34 3A D6 cmp dl,dh
-273F:4F36 72 0C jb loc_ret_1017 ; Jump if below
-273F:4F38 75 06 jnz loc_1016 ; Jump if not zero
-273F:4F3A 8B 04 mov ax,[si]
-273F:4F3C 3B 07 cmp ax,[bx]
+273F:4F2C F7 04 FFFF test word ptr [si], 0FFFFh ; Check cell
+273F:4F30 74 13 jz loc_1018 ; Skip if empty (unpopulated)
+273F:4F32 78 11 js loc_1018 ; Or if occupied
+273F:4F34 3A D6 cmp dl, dh ; Check ctr against max
+273F:4F36 72 0C jb loc_ret_1017 ; Exit if below
+273F:4F38 75 06 jnz loc_1016 ; Jump if not equal
+273F:4F3A 8B 04 mov ax, [si]
+273F:4F3C 3B 07 cmp ax, [bx]
273F:4F3E 73 04 jae loc_ret_1017 ; Jump if above or =
273F:4F40 loc_1016: ; xref 273F:4F38
273F:4F40 8B DE mov bx,si
-273F:4F42 8A D6 mov dl,dh
+273F:4F42 8A D6 mov dl, dh
273F:4F44 loc_ret_1017: ; xref 273F:4F36, 4F3E
273F:4F44 C3 retn
@@ -12131,7 +12185,7 @@
273F:4F45 E2 E0 loop locloop_1015 ; Loop if cx > 0
273F:4F47 C3 retn
- sub_121 endp
+ pathfind_scan_line endp
;\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF\xDF
@@ -26305,7 +26359,7 @@
31E4:38B4 008D[00] db 140 dup (0)
31E4:3940 0000 pathfind_buffer_end dw 0
31E4:3942 0000 pathfind_sp dw 0
-31E4:3944 0000 pathfind_v2 dw 0
+31E4:3944 0000 pathfind_countdown_ctr dw 0
31E4:3946 0000 pathfind_in_progress db 0
31E4:3947 003C[00] db 60 dup (0)
31E4:3983 000A[00] player_pathfind_data dw 5 dup (0)
Modified: scummvm/trunk/engines/lure/diassembly/Lure_notes.txt
===================================================================
--- scummvm/trunk/engines/lure/diassembly/Lure_notes.txt 2006-04-04 11:53:13 UTC (rev 21592)
+++ scummvm/trunk/engines/lure/diassembly/Lure_notes.txt 2006-04-04 11:53:45 UTC (rev 21593)
@@ -349,6 +349,26 @@
cx = Number of bits covering the width of the animation
ZF = If set, animation is not onscreen
+pathfind_populate_cells - Helper method used by character_pathfind to populate
+ a decompressed array indicating which areas of a room are walkable
+ with incrementing numbers emnating from the destination. This is
+ later used to figure out a walkable path by going from cell to
+ cell in order of decrementing index to get from source to dest
+
+pathfind_scan_line - Support method for the character_pathfind, and is used to
+ scan in a given direction
+ Input: bp = Starting position
+ bx = Destination position
+ cx = Number of loops
+ di = Change amount for each loop
+ dl = max value for comparison
+ Output: bx = New destination position
+ dl = New maximum
+
+pathfind_return_to_sp - Creates a breaking point during processing of the
+ character_pathfind method such that the next time character_pathfind
+ is called, it will pick up after the call to pathfind_return_to_sp
+
pause_for_input - Waits until either a key or a mouse button is pressed
player_inc_inventory_items - Checks if the specified hotspot is the player,
@@ -808,6 +828,10 @@
49h 1 Flags whether the hotspot has currently got the cells
of the pathfinding (walkable areas) layer that it's
base occupies as covered
+ 4Ch 1 Only known use so far is in character pathfinding, where
+ if 0, introduces a jz $+2 delay at one point, that is not
+ even inside of a loop. This flag may thus be an artefact
+ of early code that was no longer used in the final build
50h 2 Character direction: 80h=up, 40h=down, 20h=left, 10h=right
52h 2 Hotspot Id for selected hotspot
54h 2 X ending position for character + 80h - 10h
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