Implementation of basic navigation and movement across linear spaces (#24)

engine/board/menu.asm

@@ -15,12 +15,13 @@ BoardMenuScript::
 ; save after opentext to reanchor map first
 ; save before processing variables like wCurTurn due to BoardMenuScript reentry after game reset
 	farcall AutoSaveGameInOverworld
-	ld hl, wCurTurn
-	inc [hl]
 	ld hl, wTurnData
 	ld bc, wTurnDataEnd - wTurnData
 	xor a
-	jp ByteFill
+	call ByteFill
+	ld hl, wCurTurn
+	inc [hl]
+	jp LoadCurSpaceData
 
 .Die:
 	callasm BoardMenu_Die

engine/board/movement.asm

@@ -0,0 +1,29 @@
+StepTowardsNextSpace::
+	ld a, [wCurSpaceNextSpace]
+	call LoadTempSpaceData
+	ld a, [wTempSpaceXCoord]
+	ld c, a
+	ld a, [wXCoord]
+	cp c
+	jr z, .check_y
+	ld a, D_RIGHT
+	jr c, .done
+	ld a, D_LEFT
+	jr .done
+
+.check_y
+	ld a, [wTempSpaceYCoord]
+	ld c, a
+	ld a, [wYCoord]
+	cp c
+	jr z, .arrived
+	ld a, D_DOWN
+	jr c, .done
+	ld a, D_UP
+	jr .done
+
+.arrived
+	xor a
+.done
+	ld [wCurInput], a
+	ret

engine/board/spaces.asm

@@ -27,12 +27,18 @@ ArriveToRegularSpaceScript:
 	end
 
 ArriveToRegularSpace:
+; load new space
+	ld a, [wCurSpaceNextSpace]
+	ld [wCurSpace], a
+	call LoadCurSpaceData
+; decrease wSpacesLeft and copy to hScriptVar
 	ld hl, wSpacesLeft
 	dec [hl]
 	ld a, [hl]
 	ld [hScriptVar], a
+; if landed, clear spaces left sprites
 	and a
-	jp nz, UpdateSecondarySprites
+	ret nz
 	ld hl, wDisplaySecondarySprites
 	res SECONDARYSPRITES_SPACES_LEFT_F, [hl]
 	ret