From 9198f4d4b1b671973fe6c03766e1dc085c087173 Mon Sep 17 00:00:00 2001
From: xCrystal <rgr.crystal@gmail.com>
Date: Thu, 4 Jan 2024 22:30:40 +0100
Subject: [PATCH] Fix CheckOnWater while on a space tile (#34) [bugfix to
 aa91909388f46924f6c1e2721f70d451b80c2319]

---
 engine/overworld/map_setup.asm |  9 ++++-----
 home/map_objects.asm           | 12 ++++++++++++
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/engine/overworld/map_setup.asm b/engine/overworld/map_setup.asm
index 9e759d397..cc641b172 100644
--- a/engine/overworld/map_setup.asm
+++ b/engine/overworld/map_setup.asm
@@ -93,12 +93,11 @@ SkipUpdateMapSprites:
 	ret
 
 CheckUpdatePlayerSprite:
-	nop
-	call .CheckBiking
+	call .CheckForcedBiking
 	jr c, .ok
 	call .CheckSurfing
 	jr c, .ok
-	call .CheckSurfing2
+	call .ResetSurfingOrBikingState
 	jr c, .ok
 	ret
 
@@ -106,7 +105,7 @@ CheckUpdatePlayerSprite:
 	call UpdatePlayerSprite
 	ret
 
-.CheckBiking:
+.CheckForcedBiking:
 	and a
 	ld hl, wBikeFlags
 	bit BIKEFLAGS_ALWAYS_ON_BIKE_F, [hl]
@@ -116,7 +115,7 @@ CheckUpdatePlayerSprite:
 	scf
 	ret
 
-.CheckSurfing2:
+.ResetSurfingOrBikingState:
 	ld a, [wPlayerState]
 	cp PLAYER_NORMAL
 	jr z, .nope
diff --git a/home/map_objects.asm b/home/map_objects.asm
index 32ffbafba..10208dd11 100644
--- a/home/map_objects.asm
+++ b/home/map_objects.asm
@@ -78,13 +78,25 @@ GetPlayerTile::
 	ret
 
 CheckOnWater::
+; return z if on water, nz otherwise.
+; if tile permission is SPACE_TILE, wPlayerState dictates whether player is on water or not.
+; otherwise the current tile permission being LAND_TILE or WATER_TILE dictates it.
 	ld a, [wPlayerTile]
 	call GetTileCollision
+	cp SPACE_TILE
+	jr z, .check_player_state
 	sub WATER_TILE
 	ret z
 	and a
 	ret
 
+.check_player_state
+	ld a, [wPlayerState]
+	cp PLAYER_SURF
+	ret z
+	cp PLAYER_SURF_PIKA
+	ret
+
 GetTileCollision::
 ; Get the collision type of tile a.