Decompile field_ground_effect into event_object_movement.c

13 files changed, 758 insertions, 1919 deletions

diff --git a/asm/field_ground_effect.s b/asm/field_ground_effect.s
deleted file mode 100644
index 05f8ffce0..000000000
--- a/asm/field_ground_effect.s
+++ /dev/null
@@ -1,1821 +0,0 @@
-	.include "asm/macros.inc"
-	.include "constants/constants.inc"
-
-	.syntax unified
-
-	.text
-
-	thumb_func_start FieldObjectUpdateMetatileBehaviors
-@ void FieldObjectUpdateMetatileBehaviors(struct npc_state *fieldObject)
-FieldObjectUpdateMetatileBehaviors: @ 8096728
-	push {r4,lr}
-	adds r4, r0, 0
-	movs r1, 0x14
-	ldrsh r0, [r4, r1]
-	movs r2, 0x16
-	ldrsh r1, [r4, r2]
-	bl MapGridGetMetatileBehaviorAt
-	strb r0, [r4, 0x1F]
-	movs r1, 0x10
-	ldrsh r0, [r4, r1]
-	movs r2, 0x12
-	ldrsh r1, [r4, r2]
-	bl MapGridGetMetatileBehaviorAt
-	strb r0, [r4, 0x1E]
-	pop {r4}
-	pop {r0}
-	bx r0
-	thumb_func_end FieldObjectUpdateMetatileBehaviors
-
-	thumb_func_start GetGroundEffectFlags_Reflection
-@ void GetGroundEffectFlags_Reflection(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_Reflection: @ 8096750
-	push {r4,r5,lr}
-	sub sp, 0x8
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldr r0, =gUnknown_0850E5DC
-	ldr r1, [r0, 0x4]
-	ldr r0, [r0]
-	str r0, [sp]
-	str r1, [sp, 0x4]
-	adds r0, r4, 0
-	bl FieldObjectCheckForReflectiveSurface
-	lsls r0, 24
-	lsrs r2, r0, 24
-	cmp r2, 0
-	beq _08096798
-	ldrb r1, [r4, 0x2]
-	lsls r0, r1, 30
-	cmp r0, 0
-	blt _080967A2
-	movs r0, 0x3
-	negs r0, r0
-	ands r0, r1
-	movs r1, 0x2
-	orrs r0, r1
-	strb r0, [r4, 0x2]
-	subs r0, r2, 0x1
-	lsls r0, 2
-	add r0, sp
-	ldr r1, [r5]
-	ldr r0, [r0]
-	orrs r1, r0
-	str r1, [r5]
-	b _080967A2
-	.pool
-_08096798:
-	ldrb r1, [r4, 0x2]
-	movs r0, 0x3
-	negs r0, r0
-	ands r0, r1
-	strb r0, [r4, 0x2]
-_080967A2:
-	add sp, 0x8
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_Reflection
-
-	thumb_func_start GetGroundEffectFlags_TallGrassOnSpawn
-@ void GetGroundEffectFlags_TallGrassOnSpawn(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_TallGrassOnSpawn: @ 80967AC
-	push {r4,lr}
-	adds r4, r1, 0
-	ldrb r0, [r0, 0x1E]
-	bl MetatileBehavior_IsTallGrass
-	lsls r0, 24
-	cmp r0, 0
-	beq _080967C4
-	ldr r0, [r4]
-	movs r1, 0x1
-	orrs r0, r1
-	str r0, [r4]
-_080967C4:
-	pop {r4}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_TallGrassOnSpawn
-
-	thumb_func_start GetGroundEffectFlags_TallGrassOnBeginStep
-@ void GetGroundEffectFlags_TallGrassOnBeginStep(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_TallGrassOnBeginStep: @ 80967CC
-	push {r4,lr}
-	adds r4, r1, 0
-	ldrb r0, [r0, 0x1E]
-	bl MetatileBehavior_IsTallGrass
-	lsls r0, 24
-	cmp r0, 0
-	beq _080967E4
-	ldr r0, [r4]
-	movs r1, 0x2
-	orrs r0, r1
-	str r0, [r4]
-_080967E4:
-	pop {r4}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_TallGrassOnBeginStep
-
-	thumb_func_start GetGroundEffectFlags_LongGrassOnSpawn
-@ void GetGroundEffectFlags_LongGrassOnSpawn(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_LongGrassOnSpawn: @ 80967EC
-	push {r4,lr}
-	adds r4, r1, 0
-	ldrb r0, [r0, 0x1E]
-	bl MetatileBehavior_IsLongGrass
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096804
-	ldr r0, [r4]
-	movs r1, 0x4
-	orrs r0, r1
-	str r0, [r4]
-_08096804:
-	pop {r4}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_LongGrassOnSpawn
-
-	thumb_func_start GetGroundEffectFlags_LongGrassOnBeginStep
-@ void GetGroundEffectFlags_LongGrassOnBeginStep(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_LongGrassOnBeginStep: @ 809680C
-	push {r4,lr}
-	adds r4, r1, 0
-	ldrb r0, [r0, 0x1E]
-	bl MetatileBehavior_IsLongGrass
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096824
-	ldr r0, [r4]
-	movs r1, 0x8
-	orrs r0, r1
-	str r0, [r4]
-_08096824:
-	pop {r4}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_LongGrassOnBeginStep
-
-	thumb_func_start GetGroundEffectFlags_Tracks
-@ void GetGroundEffectFlags_Tracks(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_Tracks: @ 809682C
-	push {r4,r5,lr}
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4, 0x1F]
-	bl MetatileBehavior_IsDeepSand
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096846
-	ldr r0, [r5]
-	movs r1, 0x80
-	lsls r1, 1
-	b _08096862
-_08096846:
-	ldrb r0, [r4, 0x1F]
-	bl MetatileBehavior_IsSandOrDeepSand
-	lsls r0, 24
-	cmp r0, 0
-	bne _0809685E
-	ldrb r0, [r4, 0x1F]
-	bl MetatileBehavior_IsUnusedFootprintMetatile
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096866
-_0809685E:
-	ldr r0, [r5]
-	movs r1, 0x80
-_08096862:
-	orrs r0, r1
-	str r0, [r5]
-_08096866:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_Tracks
-
-	thumb_func_start GetGroundEffectFlags_SandHeap
-@ void GetGroundEffectFlags_SandHeap(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_SandHeap: @ 809686C
-	push {r4,r5,lr}
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4, 0x1E]
-	bl MetatileBehavior_IsDeepSand
-	lsls r0, 24
-	cmp r0, 0
-	beq _080968AA
-	ldrb r0, [r4, 0x1F]
-	bl MetatileBehavior_IsDeepSand
-	lsls r0, 24
-	cmp r0, 0
-	beq _080968AA
-	ldrb r1, [r4, 0x2]
-	lsls r0, r1, 27
-	cmp r0, 0
-	blt _080968B4
-	movs r0, 0x11
-	negs r0, r0
-	ands r0, r1
-	movs r1, 0x10
-	orrs r0, r1
-	strb r0, [r4, 0x2]
-	ldr r0, [r5]
-	movs r1, 0x80
-	lsls r1, 4
-	orrs r0, r1
-	str r0, [r5]
-	b _080968B4
-_080968AA:
-	ldrb r1, [r4, 0x2]
-	movs r0, 0x11
-	negs r0, r0
-	ands r0, r1
-	strb r0, [r4, 0x2]
-_080968B4:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_SandHeap
-
-	thumb_func_start GetGroundEffectFlags_ShallowFlowingWater
-@ void GetGroundEffectFlags_ShallowFlowingWater(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_ShallowFlowingWater: @ 80968BC
-	push {r4,r5,lr}
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4, 0x1E]
-	bl MetatileBehavior_IsShallowFlowingWater
-	lsls r0, 24
-	cmp r0, 0
-	beq _080968DA
-	ldrb r0, [r4, 0x1F]
-	bl MetatileBehavior_IsShallowFlowingWater
-	lsls r0, 24
-	cmp r0, 0
-	bne _080968F2
-_080968DA:
-	ldrb r0, [r4, 0x1E]
-	bl MetatileBehavior_IsPacifidlogLog
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096910
-	ldrb r0, [r4, 0x1F]
-	bl MetatileBehavior_IsPacifidlogLog
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096910
-_080968F2:
-	ldrb r1, [r4, 0x2]
-	lsls r0, r1, 28
-	cmp r0, 0
-	blt _0809691A
-	movs r0, 0x9
-	negs r0, r0
-	ands r0, r1
-	movs r1, 0x8
-	orrs r0, r1
-	strb r0, [r4, 0x2]
-	ldr r0, [r5]
-	movs r1, 0x40
-	orrs r0, r1
-	str r0, [r5]
-	b _0809691A
-_08096910:
-	ldrb r1, [r4, 0x2]
-	movs r0, 0x9
-	negs r0, r0
-	ands r0, r1
-	strb r0, [r4, 0x2]
-_0809691A:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_ShallowFlowingWater
-
-	thumb_func_start GetGroundEffectFlags_Puddle
-@ void GetGroundEffectFlags_Puddle(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_Puddle: @ 8096920
-	push {r4,r5,lr}
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4, 0x1E]
-	bl MetatileBehavior_IsPuddle
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096948
-	ldrb r0, [r4, 0x1F]
-	bl MetatileBehavior_IsPuddle
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096948
-	ldr r0, [r5]
-	movs r1, 0x80
-	lsls r1, 3
-	orrs r0, r1
-	str r0, [r5]
-_08096948:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_Puddle
-
-	thumb_func_start GetGroundEffectFlags_Ripple
-@ void GetGroundEffectFlags_Ripple(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_Ripple: @ 8096950
-	push {r4,lr}
-	adds r4, r1, 0
-	ldrb r0, [r0, 0x1E]
-	bl MetatileBehavior_HasRipples
-	lsls r0, 24
-	cmp r0, 0
-	beq _0809696A
-	ldr r0, [r4]
-	movs r1, 0x80
-	lsls r1, 2
-	orrs r0, r1
-	str r0, [r4]
-_0809696A:
-	pop {r4}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_Ripple
-
-	thumb_func_start GetGroundEffectFlags_ShortGrass
-@ void GetGroundEffectFlags_ShortGrass(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_ShortGrass: @ 8096970
-	push {r4,r5,lr}
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4, 0x1E]
-	bl MetatileBehavior_IsShortGrass
-	lsls r0, 24
-	cmp r0, 0
-	beq _080969AE
-	ldrb r0, [r4, 0x1F]
-	bl MetatileBehavior_IsShortGrass
-	lsls r0, 24
-	cmp r0, 0
-	beq _080969AE
-	ldrb r1, [r4, 0x2]
-	lsls r0, r1, 29
-	cmp r0, 0
-	blt _080969B8
-	movs r0, 0x5
-	negs r0, r0
-	ands r0, r1
-	movs r1, 0x4
-	orrs r0, r1
-	strb r0, [r4, 0x2]
-	ldr r0, [r5]
-	movs r1, 0x80
-	lsls r1, 10
-	orrs r0, r1
-	str r0, [r5]
-	b _080969B8
-_080969AE:
-	ldrb r1, [r4, 0x2]
-	movs r0, 0x5
-	negs r0, r0
-	ands r0, r1
-	strb r0, [r4, 0x2]
-_080969B8:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_ShortGrass
-
-	thumb_func_start GetGroundEffectFlags_HotSprings
-@ void GetGroundEffectFlags_HotSprings(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_HotSprings: @ 80969C0
-	push {r4,r5,lr}
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4, 0x1E]
-	bl MetatileBehavior_IsHotSprings
-	lsls r0, 24
-	cmp r0, 0
-	beq _080969FE
-	ldrb r0, [r4, 0x1F]
-	bl MetatileBehavior_IsHotSprings
-	lsls r0, 24
-	cmp r0, 0
-	beq _080969FE
-	ldrb r1, [r4, 0x2]
-	lsls r0, r1, 26
-	cmp r0, 0
-	blt _08096A08
-	movs r0, 0x21
-	negs r0, r0
-	ands r0, r1
-	movs r1, 0x20
-	orrs r0, r1
-	strb r0, [r4, 0x2]
-	ldr r0, [r5]
-	movs r1, 0x80
-	lsls r1, 11
-	orrs r0, r1
-	str r0, [r5]
-	b _08096A08
-_080969FE:
-	ldrb r1, [r4, 0x2]
-	movs r0, 0x21
-	negs r0, r0
-	ands r0, r1
-	strb r0, [r4, 0x2]
-_08096A08:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_HotSprings
-
-	thumb_func_start GetGroundEffectFlags_Seaweed
-@ void GetGroundEffectFlags_Seaweed(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_Seaweed: @ 8096A10
-	push {r4,lr}
-	adds r4, r1, 0
-	ldrb r0, [r0, 0x1E]
-	bl MetatileBehavior_IsSeaweed
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096A2A
-	ldr r0, [r4]
-	movs r1, 0x80
-	lsls r1, 12
-	orrs r0, r1
-	str r0, [r4]
-_08096A2A:
-	pop {r4}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_Seaweed
-
-	thumb_func_start GetGroundEffectFlags_JumpLanding
-@ void GetGroundEffectFlags_JumpLanding(struct npc_state *fieldObject, u32 *flags)
-GetGroundEffectFlags_JumpLanding: @ 8096A30
-	push {r4-r7,lr}
-	mov r7, r8
-	push {r7}
-	adds r7, r0, 0
-	adds r6, r1, 0
-	ldr r0, [r7]
-	ldr r1, =0x02000020
-	ands r0, r1
-	cmp r0, 0x20
-	bne _08096A82
-	movs r5, 0
-	ldr r0, =gUnknown_0850E5E4
-	mov r8, r0
-_08096A4A:
-	lsls r4, r5, 2
-	mov r0, r8
-	adds r1, r4, r0
-	ldrb r0, [r7, 0x1E]
-	ldr r1, [r1]
-	bl _call_via_r1
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096A78
-	ldr r0, =gUnknown_0850E5FC
-	adds r0, r4, r0
-	ldr r1, [r6]
-	ldr r0, [r0]
-	orrs r1, r0
-	str r1, [r6]
-	b _08096A82
-	.pool
-_08096A78:
-	adds r0, r5, 0x1
-	lsls r0, 24
-	lsrs r5, r0, 24
-	cmp r5, 0x5
-	bls _08096A4A
-_08096A82:
-	pop {r3}
-	mov r8, r3
-	pop {r4-r7}
-	pop {r0}
-	bx r0
-	thumb_func_end GetGroundEffectFlags_JumpLanding
-
-	thumb_func_start FieldObjectCheckForReflectiveSurface
-@ u8 FieldObjectCheckForReflectiveSurface(struct npc_state *fieldObject)
-FieldObjectCheckForReflectiveSurface: @ 8096A8C
-	push {r4-r7,lr}
-	mov r7, r10
-	mov r6, r9
-	mov r5, r8
-	push {r5-r7}
-	sub sp, 0x8
-	adds r5, r0, 0
-	ldrb r0, [r5, 0x5]
-	bl GetFieldObjectGraphicsInfo
-	movs r2, 0x8
-	ldrsh r1, [r0, r2]
-	adds r1, 0x8
-	lsls r1, 12
-	lsrs r1, 16
-	str r1, [sp]
-	movs r1, 0xA
-	ldrsh r0, [r0, r1]
-	adds r0, 0x8
-	lsls r0, 12
-	movs r4, 0
-	lsrs r2, r0, 16
-	str r2, [sp, 0x4]
-	asrs r0, 16
-	cmp r4, r0
-	blt _08096AC2
-	b _08096BC8
-_08096AC2:
-	movs r0, 0x1
-	mov r10, r0
-_08096AC6:
-	movs r1, 0x10
-	ldrsh r0, [r5, r1]
-	movs r2, 0x12
-	ldrsh r1, [r5, r2]
-	add r1, r10
-	lsls r4, 16
-	asrs r6, r4, 16
-	adds r1, r6
-	bl MapGridGetMetatileBehaviorAt
-	lsls r0, 24
-	lsrs r0, 24
-	bl GetReflectionTypeByMetatileBehavior
-	lsls r0, 24
-	lsrs r0, 24
-	mov r9, r4
-	cmp r0, 0
-	bne _08096BCA
-	movs r1, 0x14
-	ldrsh r0, [r5, r1]
-	movs r2, 0x16
-	ldrsh r1, [r5, r2]
-	add r1, r10
-	adds r1, r6
-	bl MapGridGetMetatileBehaviorAt
-	lsls r0, 24
-	lsrs r0, 24
-	bl GetReflectionTypeByMetatileBehavior
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0
-	bne _08096BCA
-	movs r2, 0x1
-	ldr r1, [sp]
-	lsls r0, r1, 16
-	asrs r1, r0, 16
-	mov r8, r0
-	cmp r2, r1
-	bge _08096BB6
-	movs r0, 0x80
-	lsls r0, 9
-	asrs r7, r0, 16
-_08096B20:
-	movs r1, 0x10
-	ldrsh r0, [r5, r1]
-	lsls r1, r2, 16
-	asrs r4, r1, 16
-	adds r0, r4
-	movs r2, 0x12
-	ldrsh r1, [r5, r2]
-	adds r1, r7
-	adds r1, r6
-	bl MapGridGetMetatileBehaviorAt
-	lsls r0, 24
-	lsrs r0, 24
-	bl GetReflectionTypeByMetatileBehavior
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0
-	bne _08096BCA
-	movs r1, 0x10
-	ldrsh r0, [r5, r1]
-	subs r0, r4
-	movs r2, 0x12
-	ldrsh r1, [r5, r2]
-	adds r1, r7
-	adds r1, r6
-	bl MapGridGetMetatileBehaviorAt
-	lsls r0, 24
-	lsrs r0, 24
-	bl GetReflectionTypeByMetatileBehavior
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0
-	bne _08096BCA
-	movs r1, 0x14
-	ldrsh r0, [r5, r1]
-	adds r0, r4
-	movs r2, 0x16
-	ldrsh r1, [r5, r2]
-	adds r1, r7
-	adds r1, r6
-	bl MapGridGetMetatileBehaviorAt
-	lsls r0, 24
-	lsrs r0, 24
-	bl GetReflectionTypeByMetatileBehavior
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0
-	bne _08096BCA
-	movs r1, 0x14
-	ldrsh r0, [r5, r1]
-	subs r0, r4
-	movs r2, 0x16
-	ldrsh r1, [r5, r2]
-	adds r1, r7
-	adds r1, r6
-	bl MapGridGetMetatileBehaviorAt
-	lsls r0, 24
-	lsrs r0, 24
-	bl GetReflectionTypeByMetatileBehavior
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0
-	bne _08096BCA
-	adds r0, r4, 0x1
-	lsls r0, 16
-	lsrs r2, r0, 16
-	cmp r0, r8
-	blt _08096B20
-_08096BB6:
-	movs r1, 0x80
-	lsls r1, 9
-	add r1, r9
-	lsrs r4, r1, 16
-	ldr r2, [sp, 0x4]
-	lsls r0, r2, 16
-	cmp r1, r0
-	bge _08096BC8
-	b _08096AC6
-_08096BC8:
-	movs r0, 0
-_08096BCA:
-	add sp, 0x8
-	pop {r3-r5}
-	mov r8, r3
-	mov r9, r4
-	mov r10, r5
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	thumb_func_end FieldObjectCheckForReflectiveSurface
-
-	thumb_func_start GetReflectionTypeByMetatileBehavior
-@ u8 GetReflectionTypeByMetatileBehavior(u8 metatileBehavior)
-GetReflectionTypeByMetatileBehavior: @ 8096BDC
-	push {r4,lr}
-	lsls r0, 24
-	lsrs r4, r0, 24
-	adds r0, r4, 0
-	bl MetatileBehavior_IsIce
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096BF2
-	movs r0, 0x1
-	b _08096C04
-_08096BF2:
-	adds r0, r4, 0
-	bl MetatileBehavior_IsReflective
-	lsls r0, 24
-	cmp r0, 0
-	bne _08096C02
-	movs r0, 0
-	b _08096C04
-_08096C02:
-	movs r0, 0x2
-_08096C04:
-	pop {r4}
-	pop {r1}
-	bx r1
-	thumb_func_end GetReflectionTypeByMetatileBehavior
-
-	thumb_func_start GetLedgeJumpDirection
-@ u8 GetLedgeJumpDirection(u16 x, u16 y, u8 direction)
-GetLedgeJumpDirection: @ 8096C0C
-	push {r4,lr}
-	lsls r0, 16
-	lsrs r3, r0, 16
-	lsls r1, 16
-	lsrs r1, 16
-	lsls r2, 24
-	lsrs r4, r2, 24
-	cmp r4, 0
-	beq _08096C52
-	cmp r4, 0x4
-	bls _08096C28
-	subs r0, r4, 0x4
-	lsls r0, 24
-	lsrs r4, r0, 24
-_08096C28:
-	subs r0, r4, 0x1
-	lsls r0, 24
-	lsrs r4, r0, 24
-	lsls r0, r3, 16
-	asrs r0, 16
-	lsls r1, 16
-	asrs r1, 16
-	bl MapGridGetMetatileBehaviorAt
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, =gUnknown_0850E614
-	lsls r1, r4, 2
-	adds r1, r2
-	ldr r1, [r1]
-	bl _call_via_r1
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0x1
-	beq _08096C5C
-_08096C52:
-	movs r0, 0
-	b _08096C62
-	.pool
-_08096C5C:
-	adds r0, r4, 0x1
-	lsls r0, 24
-	lsrs r0, 24
-_08096C62:
-	pop {r4}
-	pop {r1}
-	bx r1
-	thumb_func_end GetLedgeJumpDirection
-
-	thumb_func_start FieldObjectSetSpriteOamTableForLongGrass
-@ void FieldObjectSetSpriteOamTableForLongGrass(struct npc_state *fieldObject, struct obj *object)
-FieldObjectSetSpriteOamTableForLongGrass: @ 8096C68
-	push {r4-r6,lr}
-	adds r5, r0, 0
-	adds r4, r1, 0
-	ldrb r0, [r5]
-	lsls r0, 27
-	cmp r0, 0
-	blt _08096CBC
-	ldrb r0, [r5, 0x1E]
-	bl MetatileBehavior_IsLongGrass
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096CBC
-	ldrb r0, [r5, 0x1F]
-	bl MetatileBehavior_IsLongGrass
-	lsls r0, 24
-	cmp r0, 0
-	beq _08096CBC
-	adds r4, 0x42
-	ldrb r1, [r4]
-	movs r6, 0x40
-	negs r6, r6
-	adds r0, r6, 0
-	ands r0, r1
-	movs r1, 0x4
-	orrs r0, r1
-	strb r0, [r4]
-	ldrb r0, [r5, 0xB]
-	lsrs r0, 4
-	bl ZCoordToPriority
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0x1
-	bne _08096CBC
-	ldrb r0, [r4]
-	adds r1, r6, 0
-	ands r1, r0
-	movs r0, 0x5
-	orrs r1, r0
-	strb r1, [r4]
-_08096CBC:
-	pop {r4-r6}
-	pop {r0}
-	bx r0
-	thumb_func_end FieldObjectSetSpriteOamTableForLongGrass
-
-	thumb_func_start IsZCoordMismatchAt
-@ bool8 IsZCoordMismatchAt(u8 z, u16 x, u16 y)
-IsZCoordMismatchAt: @ 8096CC4
-	push {r4,lr}
-	lsls r0, 24
-	lsrs r4, r0, 24
-	lsls r1, 16
-	lsrs r0, r1, 16
-	lsls r2, 16
-	lsrs r1, r2, 16
-	cmp r4, 0
-	beq _08096CF2
-	lsls r0, 16
-	asrs r0, 16
-	lsls r1, 16
-	asrs r1, 16
-	bl MapGridGetZCoordAt
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0
-	beq _08096CF2
-	cmp r0, 0xF
-	beq _08096CF2
-	cmp r0, r4
-	bne _08096CF6
-_08096CF2:
-	movs r0, 0
-	b _08096CF8
-_08096CF6:
-	movs r0, 0x1
-_08096CF8:
-	pop {r4}
-	pop {r1}
-	bx r1
-	thumb_func_end IsZCoordMismatchAt
-
-	thumb_func_start FieldObjectUpdateZCoordAndPriority
-@ void FieldObjectUpdateZCoordAndPriority(struct npc_state *fieldObject, struct obj *object)
-FieldObjectUpdateZCoordAndPriority: @ 8096D00
-	push {r4,r5,lr}
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4, 0x3]
-	lsls r0, 29
-	cmp r0, 0
-	blt _08096D4E
-	adds r0, r4, 0
-	bl FieldObjectUpdateZCoord
-	ldr r1, =gUnknown_0850E644
-	ldrb r2, [r4, 0xB]
-	lsls r2, 24
-	lsrs r0, r2, 28
-	adds r0, r1
-	ldrb r0, [r0]
-	adds r4, r5, 0
-	adds r4, 0x42
-	movs r1, 0x3F
-	ands r1, r0
-	ldrb r3, [r4]
-	movs r0, 0x40
-	negs r0, r0
-	ands r0, r3
-	orrs r0, r1
-	strb r0, [r4]
-	ldr r0, =gUnknown_0850E634
-	lsrs r2, 28
-	adds r2, r0
-	movs r0, 0x3
-	ldrb r1, [r2]
-	ands r1, r0
-	lsls r1, 2
-	ldrb r2, [r5, 0x5]
-	movs r0, 0xD
-	negs r0, r0
-	ands r0, r2
-	orrs r0, r1
-	strb r0, [r5, 0x5]
-_08096D4E:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end FieldObjectUpdateZCoordAndPriority
-
-	thumb_func_start InitObjectPriorityByZCoord
-@ void InitObjectPriorityByZCoord(struct obj *object, u8 z)
-InitObjectPriorityByZCoord: @ 8096D5C
-	push {r4,lr}
-	lsls r1, 24
-	lsrs r1, 24
-	ldr r2, =gUnknown_0850E644
-	adds r2, r1, r2
-	ldrb r2, [r2]
-	movs r3, 0x42
-	adds r3, r0
-	mov r12, r3
-	movs r3, 0x3F
-	ands r3, r2
-	mov r2, r12
-	ldrb r4, [r2]
-	movs r2, 0x40
-	negs r2, r2
-	ands r2, r4
-	orrs r2, r3
-	mov r3, r12
-	strb r2, [r3]
-	ldr r2, =gUnknown_0850E634
-	adds r1, r2
-	movs r3, 0x3
-	ldrb r2, [r1]
-	ands r2, r3
-	lsls r2, 2
-	ldrb r3, [r0, 0x5]
-	movs r1, 0xD
-	negs r1, r1
-	ands r1, r3
-	orrs r1, r2
-	strb r1, [r0, 0x5]
-	pop {r4}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end InitObjectPriorityByZCoord
-
-	thumb_func_start ZCoordToPriority
-@ u8 ZCoordToPriority(u8 z)
-ZCoordToPriority: @ 8096DA8
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r1, =gUnknown_0850E634
-	adds r0, r1
-	ldrb r0, [r0]
-	bx lr
-	.pool
-	thumb_func_end ZCoordToPriority
-
-	thumb_func_start FieldObjectUpdateZCoord
-@ void FieldObjectUpdateZCoord(struct npc_state *fieldObject)
-FieldObjectUpdateZCoord: @ 8096DB8
-	push {r4,r5,lr}
-	adds r4, r0, 0
-	movs r1, 0x10
-	ldrsh r0, [r4, r1]
-	movs r2, 0x12
-	ldrsh r1, [r4, r2]
-	bl MapGridGetZCoordAt
-	lsls r0, 24
-	lsrs r5, r0, 24
-	movs r1, 0x14
-	ldrsh r0, [r4, r1]
-	movs r2, 0x16
-	ldrsh r1, [r4, r2]
-	bl MapGridGetZCoordAt
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r5, 0xF
-	beq _08096E06
-	cmp r0, 0xF
-	beq _08096E06
-	movs r3, 0xF
-	adds r0, r5, 0
-	ands r0, r3
-	ldrb r1, [r4, 0xB]
-	movs r2, 0x10
-	negs r2, r2
-	ands r2, r1
-	orrs r2, r0
-	strb r2, [r4, 0xB]
-	cmp r5, 0
-	beq _08096E06
-	cmp r5, 0xF
-	beq _08096E06
-	lsls r0, r5, 4
-	ands r2, r3
-	orrs r2, r0
-	strb r2, [r4, 0xB]
-_08096E06:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	thumb_func_end FieldObjectUpdateZCoord
-
-	thumb_func_start SetObjectSubpriorityByZCoord
-@ void SetObjectSubpriorityByZCoord(u8 z, struct obj *object, u8 offset)
-SetObjectSubpriorityByZCoord: @ 8096E0C
-	push {r4,r5,lr}
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r2, 24
-	lsrs r2, 24
-	adds r3, r1, 0
-	adds r3, 0x29
-	movs r5, 0
-	ldrsb r5, [r3, r5]
-	ldrh r4, [r1, 0x22]
-	ldr r3, =gSpriteCoordOffsetY
-	subs r4, r5
-	ldrh r3, [r3]
-	adds r4, r3
-	adds r4, 0x8
-	movs r3, 0xFF
-	ands r4, r3
-	lsrs r4, 4
-	movs r3, 0x10
-	subs r3, r4
-	lsls r3, 17
-	ldr r4, =gUnknown_0850E624
-	adds r0, r4
-	lsrs r3, 16
-	ldrb r0, [r0]
-	adds r3, r0
-	adds r2, r3
-	adds r1, 0x43
-	strb r2, [r1]
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end SetObjectSubpriorityByZCoord
-
-	thumb_func_start FieldObjectUpdateSubpriority
-@ void FieldObjectUpdateSubpriority(struct npc_state *fieldObject, struct obj *object)
-FieldObjectUpdateSubpriority: @ 8096E54
-	push {lr}
-	adds r2, r0, 0
-	ldrb r0, [r2, 0x3]
-	lsls r0, 29
-	cmp r0, 0
-	blt _08096E6A
-	ldrb r0, [r2, 0xB]
-	lsrs r0, 4
-	movs r2, 0x1
-	bl SetObjectSubpriorityByZCoord
-_08096E6A:
-	pop {r0}
-	bx r0
-	thumb_func_end FieldObjectUpdateSubpriority
-
-	thumb_func_start AreZCoordsCompatible
-@ bool8 AreZCoordsCompatible(u8 z1, u8 z2)
-AreZCoordsCompatible: @ 8096E70
-	push {lr}
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r1, 24
-	lsrs r1, 24
-	cmp r0, 0
-	beq _08096E86
-	cmp r1, 0
-	beq _08096E86
-	cmp r0, r1
-	bne _08096E8A
-_08096E86:
-	movs r0, 0x1
-	b _08096E8C
-_08096E8A:
-	movs r0, 0
-_08096E8C:
-	pop {r1}
-	bx r1
-	thumb_func_end AreZCoordsCompatible
-
-	thumb_func_start GroundEffect_SpawnOnTallGrass
-@ void GroundEffect_SpawnOnTallGrass(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_SpawnOnTallGrass: @ 8096E90
-	push {lr}
-	ldr r3, =gFieldEffectArguments
-	movs r2, 0x10
-	ldrsh r1, [r0, r2]
-	str r1, [r3]
-	movs r2, 0x12
-	ldrsh r1, [r0, r2]
-	str r1, [r3, 0x4]
-	ldrb r1, [r0, 0xB]
-	lsrs r1, 4
-	str r1, [r3, 0x8]
-	movs r1, 0x2
-	str r1, [r3, 0xC]
-	ldrb r1, [r0, 0x8]
-	lsls r1, 8
-	ldrb r2, [r0, 0x9]
-	orrs r1, r2
-	str r1, [r3, 0x10]
-	ldrb r0, [r0, 0xA]
-	str r0, [r3, 0x14]
-	ldr r0, =gSaveBlock1Ptr
-	ldr r1, [r0]
-	ldrb r0, [r1, 0x5]
-	lsls r0, 8
-	ldrb r1, [r1, 0x4]
-	orrs r0, r1
-	str r0, [r3, 0x18]
-	movs r0, 0x1
-	str r0, [r3, 0x1C]
-	movs r0, 0x4
-	bl FieldEffectStart
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_SpawnOnTallGrass
-
-	thumb_func_start GroundEffect_StepOnTallGrass
-@ void GroundEffect_StepOnTallGrass(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_StepOnTallGrass: @ 8096EDC
-	push {lr}
-	ldr r3, =gFieldEffectArguments
-	movs r2, 0x10
-	ldrsh r1, [r0, r2]
-	str r1, [r3]
-	movs r2, 0x12
-	ldrsh r1, [r0, r2]
-	str r1, [r3, 0x4]
-	ldrb r1, [r0, 0xB]
-	lsrs r1, 4
-	str r1, [r3, 0x8]
-	movs r1, 0x2
-	str r1, [r3, 0xC]
-	ldrb r1, [r0, 0x8]
-	lsls r1, 8
-	ldrb r2, [r0, 0x9]
-	orrs r1, r2
-	str r1, [r3, 0x10]
-	ldrb r0, [r0, 0xA]
-	str r0, [r3, 0x14]
-	ldr r0, =gSaveBlock1Ptr
-	ldr r1, [r0]
-	ldrb r0, [r1, 0x5]
-	lsls r0, 8
-	ldrb r1, [r1, 0x4]
-	orrs r0, r1
-	str r0, [r3, 0x18]
-	movs r0, 0
-	str r0, [r3, 0x1C]
-	movs r0, 0x4
-	bl FieldEffectStart
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_StepOnTallGrass
-
-	thumb_func_start GroundEffect_SpawnOnLongGrass
-@ void GroundEffect_SpawnOnLongGrass(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_SpawnOnLongGrass: @ 8096F28
-	push {lr}
-	ldr r3, =gFieldEffectArguments
-	movs r2, 0x10
-	ldrsh r1, [r0, r2]
-	str r1, [r3]
-	movs r2, 0x12
-	ldrsh r1, [r0, r2]
-	str r1, [r3, 0x4]
-	ldrb r1, [r0, 0xB]
-	lsrs r1, 4
-	str r1, [r3, 0x8]
-	movs r1, 0x2
-	str r1, [r3, 0xC]
-	ldrb r1, [r0, 0x8]
-	lsls r1, 8
-	ldrb r2, [r0, 0x9]
-	orrs r1, r2
-	str r1, [r3, 0x10]
-	ldrb r0, [r0, 0xA]
-	str r0, [r3, 0x14]
-	ldr r0, =gSaveBlock1Ptr
-	ldr r1, [r0]
-	ldrb r0, [r1, 0x5]
-	lsls r0, 8
-	ldrb r1, [r1, 0x4]
-	orrs r0, r1
-	str r0, [r3, 0x18]
-	movs r0, 0x1
-	str r0, [r3, 0x1C]
-	movs r0, 0x11
-	bl FieldEffectStart
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_SpawnOnLongGrass
-
-	thumb_func_start GroundEffect_StepOnLongGrass
-@ void GroundEffect_StepOnLongGrass(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_StepOnLongGrass: @ 8096F74
-	push {lr}
-	ldr r3, =gFieldEffectArguments
-	movs r2, 0x10
-	ldrsh r1, [r0, r2]
-	str r1, [r3]
-	movs r2, 0x12
-	ldrsh r1, [r0, r2]
-	str r1, [r3, 0x4]
-	ldrb r1, [r0, 0xB]
-	lsrs r1, 4
-	str r1, [r3, 0x8]
-	movs r1, 0x2
-	str r1, [r3, 0xC]
-	ldrb r1, [r0, 0x8]
-	lsls r1, 8
-	ldrb r2, [r0, 0x9]
-	orrs r1, r2
-	str r1, [r3, 0x10]
-	ldrb r0, [r0, 0xA]
-	str r0, [r3, 0x14]
-	ldr r0, =gSaveBlock1Ptr
-	ldr r1, [r0]
-	ldrb r0, [r1, 0x5]
-	lsls r0, 8
-	ldrb r1, [r1, 0x4]
-	orrs r0, r1
-	str r0, [r3, 0x18]
-	movs r0, 0
-	str r0, [r3, 0x1C]
-	movs r0, 0x11
-	bl FieldEffectStart
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_StepOnLongGrass
-
-	thumb_func_start GroundEffect_WaterReflection
-@ void GroundEffect_WaterReflection(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_WaterReflection: @ 8096FC0
-	push {lr}
-	movs r2, 0
-	bl SetUpReflection
-	pop {r0}
-	bx r0
-	thumb_func_end GroundEffect_WaterReflection
-
-	thumb_func_start GroundEffect_IceReflection
-@ void GroundEffect_IceReflection(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_IceReflection: @ 8096FCC
-	push {lr}
-	movs r2, 0x1
-	bl SetUpReflection
-	pop {r0}
-	bx r0
-	thumb_func_end GroundEffect_IceReflection
-
-	thumb_func_start GroundEffect_FlowingWater
-@ void GroundEffect_FlowingWater(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_FlowingWater: @ 8096FD8
-	push {lr}
-	adds r1, r0, 0
-	movs r0, 0x22
-	bl oe_exec_and_other_stuff
-	pop {r0}
-	bx r0
-	thumb_func_end GroundEffect_FlowingWater
-
-	thumb_func_start GroundEffect_SandTracks
-@ void GroundEffect_SandTracks(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_SandTracks: @ 8096FE8
-	push {r4,r5,lr}
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4, 0x5]
-	bl GetFieldObjectGraphicsInfo
-	ldr r1, =gUnknown_0850E654
-	ldrb r0, [r0, 0xD]
-	lsls r0, 2
-	adds r0, r1
-	ldr r3, [r0]
-	adds r0, r4, 0
-	adds r1, r5, 0
-	movs r2, 0
-	bl _call_via_r3
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_SandTracks
-
-	thumb_func_start GroundEffect_DeepSandTracks
-@ void GroundEffect_DeepSandTracks(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_DeepSandTracks: @ 8097014
-	push {r4,r5,lr}
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4, 0x5]
-	bl GetFieldObjectGraphicsInfo
-	ldr r1, =gUnknown_0850E654
-	ldrb r0, [r0, 0xD]
-	lsls r0, 2
-	adds r0, r1
-	ldr r3, [r0]
-	adds r0, r4, 0
-	adds r1, r5, 0
-	movs r2, 0x1
-	bl _call_via_r3
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_DeepSandTracks
-
-	thumb_func_start DoTracksGroundEffect_None
-@ void DoTracksGroundEffect_None(struct npc_state *fieldObject, struct obj *object)
-DoTracksGroundEffect_None: @ 8097040
-	bx lr
-	thumb_func_end DoTracksGroundEffect_None
-
-	thumb_func_start DoTracksGroundEffect_Footprints
-@ void DoTracksGroundEffect_Footprints(struct npc_state *fieldObject, struct obj *object)
-DoTracksGroundEffect_Footprints: @ 8097044
-	push {r4,r5,lr}
-	sub sp, 0x4
-	adds r5, r0, 0
-	lsls r4, r2, 24
-	lsrs r4, 24
-	ldr r1, =gUnknown_0850E660
-	mov r0, sp
-	movs r2, 0x4
-	bl memcpy
-	ldr r1, =gFieldEffectArguments
-	movs r2, 0x14
-	ldrsh r0, [r5, r2]
-	str r0, [r1]
-	movs r2, 0x16
-	ldrsh r0, [r5, r2]
-	str r0, [r1, 0x4]
-	movs r0, 0x95
-	str r0, [r1, 0x8]
-	movs r0, 0x2
-	str r0, [r1, 0xC]
-	ldrb r0, [r5, 0x18]
-	lsls r0, 28
-	lsrs r0, 28
-	str r0, [r1, 0x10]
-	lsls r4, 1
-	mov r1, sp
-	adds r0, r1, r4
-	ldrb r0, [r0]
-	bl FieldEffectStart
-	add sp, 0x4
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end DoTracksGroundEffect_Footprints
-
-	thumb_func_start DoTracksGroundEffect_BikeTireTracks
-@ void DoTracksGroundEffect_BikeTireTracks(struct npc_state *fieldObject, struct obj *object)
-DoTracksGroundEffect_BikeTireTracks: @ 8097094
-	push {r4,lr}
-	adds r4, r0, 0
-	ldr r1, [r4, 0x10]
-	ldr r0, [r4, 0x14]
-	cmp r1, r0
-	beq _080970D6
-	ldr r2, =gFieldEffectArguments
-	movs r1, 0x14
-	ldrsh r0, [r4, r1]
-	str r0, [r2]
-	movs r1, 0x16
-	ldrsh r0, [r4, r1]
-	str r0, [r2, 0x4]
-	movs r0, 0x95
-	str r0, [r2, 0x8]
-	movs r0, 0x2
-	str r0, [r2, 0xC]
-	ldr r3, =gUnknown_0850E664
-	ldrb r1, [r4, 0x18]
-	lsls r1, 28
-	lsrs r1, 28
-	adds r0, r4, 0
-	adds r0, 0x20
-	ldrb r0, [r0]
-	lsls r0, 2
-	subs r0, 0x5
-	adds r1, r0
-	adds r1, r3
-	ldrb r0, [r1]
-	str r0, [r2, 0x10]
-	movs r0, 0x23
-	bl FieldEffectStart
-_080970D6:
-	pop {r4}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end DoTracksGroundEffect_BikeTireTracks
-
-	thumb_func_start GroundEffect_Ripple
-@ void GroundEffect_Ripple(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_Ripple: @ 80970E4
-	push {lr}
-	bl DoRippleFieldEffect
-	pop {r0}
-	bx r0
-	thumb_func_end GroundEffect_Ripple
-
-	thumb_func_start GroundEffect_StepOnPuddle
-@ void GroundEffect_StepOnPuddle(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_StepOnPuddle: @ 80970F0
-	push {lr}
-	adds r1, r0, 0
-	movs r0, 0xF
-	bl oe_exec_and_other_stuff
-	pop {r0}
-	bx r0
-	thumb_func_end GroundEffect_StepOnPuddle
-
-	thumb_func_start GroundEffect_SandHeap
-@ void GroundEffect_SandHeap(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_SandHeap: @ 8097100
-	push {lr}
-	adds r1, r0, 0
-	movs r0, 0x27
-	bl oe_exec_and_other_stuff
-	pop {r0}
-	bx r0
-	thumb_func_end GroundEffect_SandHeap
-
-	thumb_func_start GroundEffect_JumpOnTallGrass
-@ void GroundEffect_JumpOnTallGrass(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_JumpOnTallGrass: @ 8097110
-	push {r4-r7,lr}
-	sub sp, 0x4
-	adds r5, r0, 0
-	adds r6, r1, 0
-	ldr r1, =gFieldEffectArguments
-	movs r2, 0x10
-	ldrsh r0, [r5, r2]
-	str r0, [r1]
-	movs r4, 0x12
-	ldrsh r0, [r5, r4]
-	str r0, [r1, 0x4]
-	ldrb r0, [r5, 0xB]
-	lsrs r0, 4
-	str r0, [r1, 0x8]
-	movs r0, 0x2
-	str r0, [r1, 0xC]
-	movs r0, 0xC
-	bl FieldEffectStart
-	ldrb r0, [r5, 0x8]
-	ldrb r1, [r5, 0x9]
-	ldrb r2, [r5, 0xA]
-	movs r7, 0x10
-	ldrsh r3, [r5, r7]
-	movs r7, 0x12
-	ldrsh r4, [r5, r7]
-	str r4, [sp]
-	bl sub_81546C8
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0x40
-	bne _0809715A
-	adds r0, r5, 0
-	adds r1, r6, 0
-	bl GroundEffect_SpawnOnTallGrass
-_0809715A:
-	add sp, 0x4
-	pop {r4-r7}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_JumpOnTallGrass
-
-	thumb_func_start GroundEffect_JumpOnLongGrass
-@ void GroundEffect_JumpOnLongGrass(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_JumpOnLongGrass: @ 8097168
-	push {lr}
-	ldr r2, =gFieldEffectArguments
-	movs r3, 0x10
-	ldrsh r1, [r0, r3]
-	str r1, [r2]
-	movs r3, 0x12
-	ldrsh r1, [r0, r3]
-	str r1, [r2, 0x4]
-	ldrb r0, [r0, 0xB]
-	lsrs r0, 4
-	str r0, [r2, 0x8]
-	movs r0, 0x2
-	str r0, [r2, 0xC]
-	movs r0, 0x12
-	bl FieldEffectStart
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_JumpOnLongGrass
-
-	thumb_func_start GroundEffect_JumpOnShallowWater
-@ void GroundEffect_JumpOnShallowWater(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_JumpOnShallowWater: @ 8097190
-	push {r4,lr}
-	ldr r3, =gFieldEffectArguments
-	movs r4, 0x10
-	ldrsh r2, [r0, r4]
-	str r2, [r3]
-	movs r4, 0x12
-	ldrsh r2, [r0, r4]
-	str r2, [r3, 0x4]
-	ldrb r0, [r0, 0xB]
-	lsrs r0, 4
-	str r0, [r3, 0x8]
-	ldrb r0, [r1, 0x5]
-	lsls r0, 28
-	lsrs r0, 30
-	str r0, [r3, 0xC]
-	movs r0, 0x10
-	bl FieldEffectStart
-	pop {r4}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_JumpOnShallowWater
-
-	thumb_func_start GroundEffect_JumpOnWater
-@ void GroundEffect_JumpOnWater(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_JumpOnWater: @ 80971C0
-	push {r4,lr}
-	ldr r3, =gFieldEffectArguments
-	movs r4, 0x10
-	ldrsh r2, [r0, r4]
-	str r2, [r3]
-	movs r4, 0x12
-	ldrsh r2, [r0, r4]
-	str r2, [r3, 0x4]
-	ldrb r0, [r0, 0xB]
-	lsrs r0, 4
-	str r0, [r3, 0x8]
-	ldrb r0, [r1, 0x5]
-	lsls r0, 28
-	lsrs r0, 30
-	str r0, [r3, 0xC]
-	movs r0, 0xE
-	bl FieldEffectStart
-	pop {r4}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_JumpOnWater
-
-	thumb_func_start GroundEffect_JumpLandingDust
-@ void GroundEffect_JumpLandingDust(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_JumpLandingDust: @ 80971F0
-	push {r4,lr}
-	ldr r3, =gFieldEffectArguments
-	movs r4, 0x10
-	ldrsh r2, [r0, r4]
-	str r2, [r3]
-	movs r4, 0x12
-	ldrsh r2, [r0, r4]
-	str r2, [r3, 0x4]
-	ldrb r0, [r0, 0xB]
-	lsrs r0, 4
-	str r0, [r3, 0x8]
-	ldrb r0, [r1, 0x5]
-	lsls r0, 28
-	lsrs r0, 30
-	str r0, [r3, 0xC]
-	movs r0, 0xA
-	bl FieldEffectStart
-	pop {r4}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_JumpLandingDust
-
-	thumb_func_start GroundEffect_ShortGrass
-@ void GroundEffect_ShortGrass(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_ShortGrass: @ 8097220
-	push {lr}
-	adds r1, r0, 0
-	movs r0, 0x29
-	bl oe_exec_and_other_stuff
-	pop {r0}
-	bx r0
-	thumb_func_end GroundEffect_ShortGrass
-
-	thumb_func_start GroundEffect_HotSprings
-@ void GroundEffect_HotSprings(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_HotSprings: @ 8097230
-	push {lr}
-	adds r1, r0, 0
-	movs r0, 0x2A
-	bl oe_exec_and_other_stuff
-	pop {r0}
-	bx r0
-	thumb_func_end GroundEffect_HotSprings
-
-	thumb_func_start GroundEffect_Seaweed
-@ void GroundEffect_Seaweed(struct npc_state *fieldObject, struct obj *object)
-GroundEffect_Seaweed: @ 8097240
-	push {lr}
-	ldr r2, =gFieldEffectArguments
-	movs r3, 0x10
-	ldrsh r1, [r0, r3]
-	str r1, [r2]
-	movs r1, 0x12
-	ldrsh r0, [r0, r1]
-	str r0, [r2, 0x4]
-	movs r0, 0x35
-	bl FieldEffectStart
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end GroundEffect_Seaweed
-
-	thumb_func_start DoFlaggedGroundEffects
-@ void DoFlaggedGroundEffects(struct npc_state *fieldObject, struct obj *object, u32 flags)
-DoFlaggedGroundEffects: @ 8097260
-	push {r4-r7,lr}
-	mov r7, r8
-	push {r7}
-	adds r6, r0, 0
-	adds r7, r1, 0
-	adds r5, r2, 0
-	bl FieldObjectIsFarawayIslandMew
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0x1
-	bne _08097284
-	adds r0, r6, 0
-	bl sub_81D4A58
-	lsls r0, 24
-	cmp r0, 0
-	beq _080972AC
-_08097284:
-	movs r4, 0
-	ldr r0, =gUnknown_0850E674
-	mov r8, r0
-_0809728A:
-	movs r0, 0x1
-	ands r0, r5
-	cmp r0, 0
-	beq _080972A0
-	lsls r0, r4, 2
-	add r0, r8
-	ldr r2, [r0]
-	adds r0, r6, 0
-	adds r1, r7, 0
-	bl _call_via_r2
-_080972A0:
-	adds r0, r4, 0x1
-	lsls r0, 24
-	lsrs r4, r0, 24
-	lsrs r5, 1
-	cmp r4, 0x13
-	bls _0809728A
-_080972AC:
-	pop {r3}
-	mov r8, r3
-	pop {r4-r7}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end DoFlaggedGroundEffects
-
-	thumb_func_start filters_out_some_ground_effects
-@ void filters_out_some_ground_effects(struct npc_state *fieldObject, u32 *flags)
-filters_out_some_ground_effects: @ 80972BC
-	push {lr}
-	adds r2, r0, 0
-	adds r3, r1, 0
-	ldrb r0, [r2]
-	lsls r0, 27
-	cmp r0, 0
-	bge _080972EA
-	ldrb r1, [r2, 0x2]
-	movs r0, 0x5
-	negs r0, r0
-	ands r0, r1
-	movs r1, 0x11
-	negs r1, r1
-	ands r0, r1
-	adds r1, 0x8
-	ands r0, r1
-	subs r1, 0x18
-	ands r0, r1
-	strb r0, [r2, 0x2]
-	ldr r0, [r3]
-	ldr r1, =0xfff9f7bd
-	ands r0, r1
-	str r0, [r3]
-_080972EA:
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end filters_out_some_ground_effects
-
-	thumb_func_start FilterOutStepOnPuddleGroundEffectIfJumping
-@ void FilterOutStepOnPuddleGroundEffectIfJumping(struct npc_state *fieldObject, u32 *flags)
-FilterOutStepOnPuddleGroundEffectIfJumping: @ 80972F4
-	push {lr}
-	adds r2, r1, 0
-	ldrb r0, [r0]
-	lsls r0, 26
-	cmp r0, 0
-	bge _08097308
-	ldr r0, [r2]
-	ldr r1, =0xfffffbff
-	ands r0, r1
-	str r0, [r2]
-_08097308:
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end FilterOutStepOnPuddleGroundEffectIfJumping
-
-	thumb_func_start DoGroundEffects_OnSpawn
-@ void DoGroundEffects_OnSpawn(struct npc_state *fieldObject, struct obj *object)
-DoGroundEffects_OnSpawn: @ 8097310
-	push {r4,r5,lr}
-	sub sp, 0x4
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4]
-	lsls r0, 29
-	cmp r0, 0
-	bge _08097354
-	movs r0, 0
-	str r0, [sp]
-	adds r0, r4, 0
-	bl FieldObjectUpdateZCoordAndPriority
-	adds r0, r4, 0
-	mov r1, sp
-	bl GetAllGroundEffectFlags_OnSpawn
-	adds r0, r4, 0
-	adds r1, r5, 0
-	bl FieldObjectSetSpriteOamTableForLongGrass
-	ldr r2, [sp]
-	adds r0, r4, 0
-	adds r1, r5, 0
-	bl DoFlaggedGroundEffects
-	ldrb r1, [r4]
-	movs r0, 0x5
-	negs r0, r0
-	ands r0, r1
-	movs r1, 0x11
-	negs r1, r1
-	ands r0, r1
-	strb r0, [r4]
-_08097354:
-	add sp, 0x4
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	thumb_func_end DoGroundEffects_OnSpawn
-
-	thumb_func_start DoGroundEffects_OnBeginStep
-@ void DoGroundEffects_OnBeginStep(struct npc_state *fieldObject, struct obj *object)
-DoGroundEffects_OnBeginStep: @ 809735C
-	push {r4,r5,lr}
-	sub sp, 0x4
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4]
-	lsls r0, 29
-	cmp r0, 0
-	bge _080973A8
-	movs r0, 0
-	str r0, [sp]
-	adds r0, r4, 0
-	bl FieldObjectUpdateZCoordAndPriority
-	adds r0, r4, 0
-	mov r1, sp
-	bl GetAllGroundEffectFlags_OnBeginStep
-	adds r0, r4, 0
-	adds r1, r5, 0
-	bl FieldObjectSetSpriteOamTableForLongGrass
-	adds r0, r4, 0
-	mov r1, sp
-	bl filters_out_some_ground_effects
-	ldr r2, [sp]
-	adds r0, r4, 0
-	adds r1, r5, 0
-	bl DoFlaggedGroundEffects
-	ldrb r1, [r4]
-	movs r0, 0x5
-	negs r0, r0
-	ands r0, r1
-	movs r1, 0x11
-	negs r1, r1
-	ands r0, r1
-	strb r0, [r4]
-_080973A8:
-	add sp, 0x4
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	thumb_func_end DoGroundEffects_OnBeginStep
-
-	thumb_func_start DoGroundEffects_OnFinishStep
-@ void DoGroundEffects_OnFinishStep(struct npc_state *fieldObject, struct obj *object)
-DoGroundEffects_OnFinishStep: @ 80973B0
-	push {r4,r5,lr}
-	sub sp, 0x4
-	adds r4, r0, 0
-	adds r5, r1, 0
-	ldrb r0, [r4]
-	lsls r0, 28
-	cmp r0, 0
-	bge _080973FC
-	movs r0, 0
-	str r0, [sp]
-	adds r0, r4, 0
-	bl FieldObjectUpdateZCoordAndPriority
-	adds r0, r4, 0
-	mov r1, sp
-	bl GetAllGroundEffectFlags_OnFinishStep
-	adds r0, r4, 0
-	adds r1, r5, 0
-	bl FieldObjectSetSpriteOamTableForLongGrass
-	adds r0, r4, 0
-	mov r1, sp
-	bl FilterOutStepOnPuddleGroundEffectIfJumping
-	ldr r2, [sp]
-	adds r0, r4, 0
-	adds r1, r5, 0
-	bl DoFlaggedGroundEffects
-	ldrb r1, [r4]
-	movs r0, 0x9
-	negs r0, r0
-	ands r0, r1
-	movs r1, 0x21
-	negs r1, r1
-	ands r0, r1
-	strb r0, [r4]
-_080973FC:
-	add sp, 0x4
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	thumb_func_end DoGroundEffects_OnFinishStep
-
-	.align 2, 0 @ Don't pad with nop.
diff --git a/data/field_ground_effect.s b/data/field_ground_effect.s
index 989d2add7..686d9396b 100644
--- a/data/field_ground_effect.s
+++ b/data/field_ground_effect.s
@@ -4,66 +4,3 @@
     .section .rodata
     .align 2, 0
 
-gUnknown_0850E5DC:: @ 850E5DC
-	.4byte 0x00000020, 0x00000010
-
-gUnknown_0850E5E4:: @ 850E5E4
-	.4byte MetatileBehavior_IsTallGrass
-	.4byte MetatileBehavior_IsLongGrass
-	.4byte MetatileBehavior_IsPuddle
-	.4byte MetatileBehavior_IsSurfableWaterOrUnderwater
-	.4byte MetatileBehavior_IsShallowFlowingWater
-	.4byte ShouldDoJumpLandingDustEffect
-
-gUnknown_0850E5FC:: @ 850E5FC
-	.4byte 0x00001000, 0x00002000, 0x00004000, 0x00008000, 0x00004000, 0x00010000
-
-gUnknown_0850E614:: @ 850E614
-	.4byte MetatileBehavior_IsJumpSouth
-	.4byte MetatileBehavior_IsJumpNorth
-	.4byte MetatileBehavior_IsJumpWest
-	.4byte MetatileBehavior_IsJumpEast
-
-gUnknown_0850E624:: @ 850E624
-	.byte 0x73, 0x73, 0x53, 0x73, 0x53, 0x73, 0x53, 0x73, 0x53, 0x73, 0x53, 0x73, 0x53, 0x00, 0x00, 0x73
-
-gUnknown_0850E634:: @ 850E634
-	.byte 0x02, 0x02, 0x02, 0x02, 0x01, 0x02, 0x01, 0x02, 0x01, 0x02, 0x01, 0x02, 0x01, 0x00, 0x00, 0x02
-
-gUnknown_0850E644:: @ 850E644
-	.byte 0x01, 0x01, 0x01, 0x01, 0x02, 0x01, 0x02, 0x01, 0x02, 0x01, 0x02, 0x01, 0x02, 0x00, 0x00, 0x01
-
-gUnknown_0850E654:: @ 850E654
-	.4byte DoTracksGroundEffect_None
-	.4byte DoTracksGroundEffect_Footprints
-	.4byte DoTracksGroundEffect_BikeTireTracks
-
-gUnknown_0850E660:: @ 850E660
-	.byte 13, 0
-	.byte 24, 0
-
-gUnknown_0850E664:: @ 850E664
-	.byte 0x01, 0x02, 0x07, 0x08, 0x01, 0x02, 0x06, 0x05, 0x05, 0x08, 0x03, 0x04, 0x06, 0x07, 0x03, 0x04
-
-gUnknown_0850E674:: @ 850E674
-	.4byte GroundEffect_SpawnOnTallGrass
-	.4byte GroundEffect_StepOnTallGrass
-	.4byte GroundEffect_SpawnOnLongGrass
-	.4byte GroundEffect_StepOnLongGrass
-	.4byte GroundEffect_WaterReflection
-	.4byte GroundEffect_IceReflection
-	.4byte GroundEffect_FlowingWater
-	.4byte GroundEffect_SandTracks
-	.4byte GroundEffect_DeepSandTracks
-	.4byte GroundEffect_Ripple
-	.4byte GroundEffect_StepOnPuddle
-	.4byte GroundEffect_SandHeap
-	.4byte GroundEffect_JumpOnTallGrass
-	.4byte GroundEffect_JumpOnLongGrass
-	.4byte GroundEffect_JumpOnShallowWater
-	.4byte GroundEffect_JumpOnWater
-	.4byte GroundEffect_JumpLandingDust
-	.4byte GroundEffect_ShortGrass
-	.4byte GroundEffect_HotSprings
-	.4byte GroundEffect_Seaweed
-
diff --git a/include/event_object_movement.h b/include/event_object_movement.h
index 7fd1fc93a..4e0d4ad22 100644
--- a/include/event_object_movement.h
+++ b/include/event_object_movement.h
@@ -20,6 +20,27 @@ enum SpinnerRunnerFollowPatterns {
     RUNFOLLOW_SOUTH_EAST_WEST
 };
 
+#define GROUND_EFFECT_FLAG_TALL_GRASS_ON_SPAWN   (1 << 0)
+#define GROUND_EFFECT_FLAG_TALL_GRASS_ON_MOVE    (1 << 1)
+#define GROUND_EFFECT_FLAG_LONG_GRASS_ON_SPAWN   (1 << 2)
+#define GROUND_EFFECT_FLAG_LONG_GRASS_ON_MOVE    (1 << 3)
+#define GROUND_EFFECT_FLAG_ICE_REFLECTION        (1 << 4)
+#define GROUND_EFFECT_FLAG_REFLECTION            (1 << 5)
+#define GROUND_EFFECT_FLAG_SHALLOW_FLOWING_WATER (1 << 6)
+#define GROUND_EFFECT_FLAG_SAND                  (1 << 7)
+#define GROUND_EFFECT_FLAG_DEEP_SAND             (1 << 8)
+#define GROUND_EFFECT_FLAG_RIPPLES               (1 << 9)
+#define GROUND_EFFECT_FLAG_PUDDLE                (1 << 10)
+#define GROUND_EFFECT_FLAG_SAND_PILE             (1 << 11)
+#define GROUND_EFFECT_FLAG_LAND_IN_TALL_GRASS    (1 << 12)
+#define GROUND_EFFECT_FLAG_LAND_IN_LONG_GRASS    (1 << 13)
+#define GROUND_EFFECT_FLAG_LAND_IN_SHALLOW_WATER (1 << 14)
+#define GROUND_EFFECT_FLAG_LAND_IN_DEEP_WATER    (1 << 15)
+#define GROUND_EFFECT_FLAG_LAND_ON_NORMAL_GROUND (1 << 16)
+#define GROUND_EFFECT_FLAG_SHORT_GRASS           (1 << 17)
+#define GROUND_EFFECT_FLAG_HOT_SPRINGS           (1 << 18)
+#define GROUND_EFFECT_FLAG_SEAWEED               (1 << 19)
+
 // Exported RAM declarations
 
 // Exported ROM declarations
@@ -95,6 +116,11 @@ u8 AddCameraObject(u8 linkedSpriteId);
 void UpdateFieldObjectsForCameraUpdate(s16 x, s16 y);
 u8 GetSimpleGoAnimId(u32);
 u8 sub_8093514(u32);
+bool8 AreZCoordsCompatible(u8, u8);
+u8 ZCoordToPriority(u8);
+void FieldObjectUpdateZCoord(struct MapObject *pObject);
+void SetObjectSubpriorityByZCoord(u8, struct Sprite *, u8);
+bool8 IsZCoordMismatchAt(u8, s16, s16);
 
 // Exported data declarations
 
diff --git a/include/field_effect_helpers.h b/include/field_effect_helpers.h
index 3c9e00b62..faf6290e4 100644
--- a/include/field_effect_helpers.h
+++ b/include/field_effect_helpers.h
@@ -15,5 +15,8 @@ bool8 sub_8155DA0(struct MapObject *);
 void sub_8155D78(struct MapObject *);
 void sub_81555AC(u8, u8);
 void ash(s16, s16, u16, s16);
+void SetUpReflection(struct MapObject*, struct Sprite*, u8);
+u32 StartFieldEffectForEventObject(u8, struct MapObject*);
+u8 sub_81546C8(u8, u8, u8, s16, s16);
 
 #endif //GUARD_FIELD_EFFECT_HELPERS_H
diff --git a/include/field_ground_effect.h b/include/field_ground_effect.h
deleted file mode 100644
index 89b14aed1..000000000
--- a/include/field_ground_effect.h
+++ /dev/null
@@ -1,24 +0,0 @@
-//
-// Created by scott on 9/6/2017.
-//
-
-#ifndef GUARD_FIELD_GROUND_EFFECT_H
-#define GUARD_FIELD_GROUND_EFFECT_H
-
-// Exported type declarations
-
-// Exported RAM declarations
-
-// Exported ROM declarations
-u8 ZCoordToPriority(u8);
-void FieldObjectUpdateZCoord(struct MapObject *pObject);
-void SetObjectSubpriorityByZCoord(u8, struct Sprite *, u8);
-void InitObjectPriorityByZCoord(struct Sprite *, u8);
-bool8 IsZCoordMismatchAt(u8, s16, s16);
-bool8 AreZCoordsCompatible(u8, u8);
-void FieldObjectUpdateSubpriority(struct MapObject *, struct Sprite *);
-void DoGroundEffects_OnSpawn(struct MapObject *, struct Sprite *);
-void DoGroundEffects_OnBeginStep(struct MapObject *, struct Sprite *);
-void DoGroundEffects_OnFinishStep(struct MapObject *, struct Sprite *);
-
-#endif //GUARD_FIELD_GROUND_EFFECT_H
diff --git a/include/fieldmap.h b/include/fieldmap.h
index 699595580..01218493a 100644
--- a/include/fieldmap.h
+++ b/include/fieldmap.h
@@ -14,6 +14,7 @@ int CanCameraMoveInDirection(int direction);
 u16 GetBehaviorByMetatileId(u16 metatileId);
 void sav1_camera_get_focus_coords(u16 *x, u16 *y);
 u8 MapGridGetMetatileLayerTypeAt(s32 x, s32 y);
+u8 MapGridGetZCoordAt(int x, int y);
 u8 CameraMove(s32 deltaX, s32 deltaY);
 void mapheader_copy_mapdata_with_padding(struct MapHeader *mapHeader);
 void map_copy_with_padding(u16 *map, u16 width, u16 height);
diff --git a/include/metatile_behavior.h b/include/metatile_behavior.h
index d6743b788..4b9fd2488 100644
--- a/include/metatile_behavior.h
+++ b/include/metatile_behavior.h
@@ -1,7 +1,7 @@
 #ifndef GUARD_METATILE_BEHAVIOR
 #define GUARD_METATILE_BEHAVIOR
 
-bool8 ShouldDoJumpLandingDustEffect(u8);
+bool8 MetatileBehavior_IsATile(u8);
 bool8 MetatileBehavior_IsEncounterTile(u8);
 bool8 MetatileBehavior_IsJumpEast(u8);
 bool8 MetatileBehavior_IsJumpWest(u8);
diff --git a/include/pokenav.h b/include/pokenav.h
index 42affc938..734a1ec3f 100644
--- a/include/pokenav.h
+++ b/include/pokenav.h
@@ -21,6 +21,7 @@ void sub_81D1EC0(void);
 void sub_81D1D04(u8);
 bool8 sub_81D1C44(u8);
 void sub_81D5FB4(u16*);
+bool8 sub_81D4A58(struct MapObject*);
 
 
 #endif //GUARD_POKENAV_H
diff --git a/ld_script.txt b/ld_script.txt
index 51e641fd1..b4d69ec4a 100644
--- a/ld_script.txt
+++ b/ld_script.txt
@@ -93,7 +93,6 @@ SECTIONS {
         src/field_door.o(.text);
         asm/field_player_avatar.o(.text);
         src/event_object_movement.o(.text);
-        asm/field_ground_effect.o(.text);
         src/event_object_movement_helpers.o(.text);
         src/field_message_box.o(.text);
         src/map_obj_lock.o(.text);
@@ -398,7 +397,7 @@ SECTIONS {
         src/field_door.o(.rodata);
         data/field_player_avatar.o(.rodata);
         data/event_object_movement.o(.rodata);
-        data/field_ground_effect.o(.rodata);
+        src/event_object_movement.o(.rodata);
         data/map_obj_8097404.o(.rodata);
         src/text_window.o(.rodata);
         src/scrcmd.o(.rodata);
diff --git a/src/event_object_movement.c b/src/event_object_movement.c
index 261f234f4..5c6f503ef 100644
--- a/src/event_object_movement.c
+++ b/src/event_object_movement.c
@@ -13,7 +13,6 @@
 #include "event_data.h"
 #include "rom_818CFC8.h"
 #include "rom_81BE66C.h"
-#include "field_ground_effect.h"
 #include "event_object_movement_helpers.h"
 #include "mauville_old_man.h"
 #include "metatile_behavior.h"
@@ -23,6 +22,7 @@
 #include "trainer_see.h"
 #include "decoration.h"
 #include "event_object_movement.h"
+#include "pokenav.h"
 
 #define NUM_FIELD_MAP_OBJECT_TEMPLATES 0x51
 
@@ -175,7 +175,7 @@ extern u8 (*const gUnknown_0850DEE8[5])(u8);
 extern const s16 gUnknown_0850DFBC[3];
 extern const s16 gUnknown_0850DFC2[3];
 
-/*static*/ void FieldObjectUpdateMetatileBehaviors(struct MapObject*);
+static void FieldObjectUpdateMetatileBehaviors(struct MapObject*);
 /*static*/ void GetAllGroundEffectFlags_OnBeginStep(struct MapObject*, u32*);
 /*static*/ void GetGroundEffectFlags_Reflection(struct MapObject*, u32*);
 /*static*/ void GetGroundEffectFlags_TallGrassOnSpawn(struct MapObject*, u32*);
@@ -191,6 +191,17 @@ extern const s16 gUnknown_0850DFC2[3];
 /*static*/ void GetGroundEffectFlags_Ripple(struct MapObject*, u32*);
 /*static*/ void GetGroundEffectFlags_Seaweed(struct MapObject*, u32*);
 /*static*/ void GetGroundEffectFlags_JumpLanding(struct MapObject*, u32*);
+/*static*/ u8 FieldObjectCheckForReflectiveSurface(struct MapObject*);
+static u8 GetReflectionTypeByMetatileBehavior(u32);
+static void InitObjectPriorityByZCoord(struct Sprite *sprite, u8 z);
+static void FieldObjectUpdateSubpriority(struct MapObject*, struct Sprite*);
+static void DoTracksGroundEffect_None(struct MapObject*, struct Sprite*, u8);
+static void DoTracksGroundEffect_Footprints(struct MapObject*, struct Sprite*, u8);
+static void DoTracksGroundEffect_BikeTireTracks(struct MapObject*, struct Sprite*, u8);
+/*static*/ void DoRippleFieldEffect(struct MapObject*, struct Sprite*);
+static void DoGroundEffects_OnSpawn(struct MapObject*, struct Sprite*);
+static void DoGroundEffects_OnBeginStep(struct MapObject*, struct Sprite*);
+static void DoGroundEffects_OnFinishStep(struct MapObject*, struct Sprite*);
 
 
 // Code
@@ -5174,3 +5185,712 @@ static void npc_update_obj_anim_flag(struct MapObject *mapObject, struct Sprite
     GetGroundEffectFlags_Seaweed(eventObj, flags);
     GetGroundEffectFlags_JumpLanding(eventObj, flags);
 }
+
+static void FieldObjectUpdateMetatileBehaviors(struct MapObject *eventObj)
+{
+    eventObj->previousMetatileBehavior = MapGridGetMetatileBehaviorAt(eventObj->previousCoords.x, eventObj->previousCoords.y);
+    eventObj->currentMetatileBehavior = MapGridGetMetatileBehaviorAt(eventObj->currentCoords.x, eventObj->currentCoords.y);
+}
+
+void GetGroundEffectFlags_Reflection(struct MapObject *eventObj, u32 *flags)
+{
+    u32 reflectionFlags[2] = { GROUND_EFFECT_FLAG_REFLECTION, GROUND_EFFECT_FLAG_ICE_REFLECTION };
+    u8 type = FieldObjectCheckForReflectiveSurface(eventObj);
+
+    if (type)
+    {
+        if (!eventObj->hasReflection)
+        {
+            eventObj->hasReflection = 0;
+            eventObj->hasReflection = 1;
+            *flags |= reflectionFlags[type - 1];
+        }
+    }
+    else
+    {
+        eventObj->hasReflection = 0;
+    }
+}
+
+void GetGroundEffectFlags_TallGrassOnSpawn(struct MapObject *eventObj, u32 *flags)
+{
+    if (MetatileBehavior_IsTallGrass(eventObj->currentMetatileBehavior))
+        *flags |= GROUND_EFFECT_FLAG_TALL_GRASS_ON_SPAWN;
+}
+
+void GetGroundEffectFlags_TallGrassOnBeginStep(struct MapObject *eventObj, u32 *flags)
+{
+    if (MetatileBehavior_IsTallGrass(eventObj->currentMetatileBehavior))
+        *flags |= GROUND_EFFECT_FLAG_TALL_GRASS_ON_MOVE;
+}
+
+void GetGroundEffectFlags_LongGrassOnSpawn(struct MapObject *eventObj, u32 *flags)
+{
+    if (MetatileBehavior_IsLongGrass(eventObj->currentMetatileBehavior))
+        *flags |= GROUND_EFFECT_FLAG_LONG_GRASS_ON_SPAWN;
+}
+
+void GetGroundEffectFlags_LongGrassOnBeginStep(struct MapObject *eventObj, u32 *flags)
+{
+    if (MetatileBehavior_IsLongGrass(eventObj->currentMetatileBehavior))
+        *flags |= GROUND_EFFECT_FLAG_LONG_GRASS_ON_MOVE;
+}
+
+void GetGroundEffectFlags_Tracks(struct MapObject *eventObj, u32 *flags)
+{
+    if (MetatileBehavior_IsDeepSand(eventObj->previousMetatileBehavior))
+    {
+        *flags |= GROUND_EFFECT_FLAG_DEEP_SAND;
+    }
+    else if (MetatileBehavior_IsSandOrDeepSand(eventObj->previousMetatileBehavior)
+             || MetatileBehavior_IsUnusedFootprintMetatile(eventObj->previousMetatileBehavior))
+    {
+        *flags |= GROUND_EFFECT_FLAG_SAND;
+    }
+}
+
+void GetGroundEffectFlags_SandHeap(struct MapObject *eventObj, u32 *flags)
+{
+    if (MetatileBehavior_IsDeepSand(eventObj->currentMetatileBehavior)
+        && MetatileBehavior_IsDeepSand(eventObj->previousMetatileBehavior))
+    {
+        if (!eventObj->inSandPile)
+        {
+            eventObj->inSandPile = 0;
+            eventObj->inSandPile = 1;
+            *flags |= GROUND_EFFECT_FLAG_SAND_PILE;
+        }
+    }
+    else
+    {
+        eventObj->inSandPile = 0;
+    }
+}
+
+void GetGroundEffectFlags_ShallowFlowingWater(struct MapObject *eventObj, u32 *flags)
+{
+    if ((MetatileBehavior_IsShallowFlowingWater(eventObj->currentMetatileBehavior)
+         && MetatileBehavior_IsShallowFlowingWater(eventObj->previousMetatileBehavior))
+        || (MetatileBehavior_IsPacifidlogLog(eventObj->currentMetatileBehavior)
+            && MetatileBehavior_IsPacifidlogLog(eventObj->previousMetatileBehavior)))
+    {
+        if (!eventObj->inShallowFlowingWater)
+        {
+            eventObj->inShallowFlowingWater = 0;
+            eventObj->inShallowFlowingWater = 1;
+            *flags |= GROUND_EFFECT_FLAG_SHALLOW_FLOWING_WATER;
+        }
+    }
+    else
+    {
+        eventObj->inShallowFlowingWater = 0;
+    }
+}
+
+void GetGroundEffectFlags_Puddle(struct MapObject *eventObj, u32 *flags)
+{
+    if (MetatileBehavior_IsPuddle(eventObj->currentMetatileBehavior)
+        && MetatileBehavior_IsPuddle(eventObj->previousMetatileBehavior))
+    {
+        *flags |= GROUND_EFFECT_FLAG_PUDDLE;
+    }
+}
+
+void GetGroundEffectFlags_Ripple(struct MapObject *eventObj, u32 *flags)
+{
+    if (MetatileBehavior_HasRipples(eventObj->currentMetatileBehavior))
+        *flags |= GROUND_EFFECT_FLAG_RIPPLES;
+}
+
+void GetGroundEffectFlags_ShortGrass(struct MapObject *eventObj, u32 *flags)
+{
+    if (MetatileBehavior_IsShortGrass(eventObj->currentMetatileBehavior)
+        && MetatileBehavior_IsShortGrass(eventObj->previousMetatileBehavior))
+    {
+        if (!eventObj->inShortGrass)
+        {
+            eventObj->inShortGrass = 0;
+            eventObj->inShortGrass = 1;
+            *flags |= GROUND_EFFECT_FLAG_SHORT_GRASS;
+        }
+    }
+    else
+    {
+        eventObj->inShortGrass = 0;
+    }
+}
+
+void GetGroundEffectFlags_HotSprings(struct MapObject *eventObj, u32 *flags)
+{
+    if (MetatileBehavior_IsHotSprings(eventObj->currentMetatileBehavior)
+        && MetatileBehavior_IsHotSprings(eventObj->previousMetatileBehavior))
+    {
+        if (!eventObj->inHotSprings)
+        {
+            eventObj->inHotSprings = 0;
+            eventObj->inHotSprings = 1;
+            *flags |= GROUND_EFFECT_FLAG_HOT_SPRINGS;
+        }
+    }
+    else
+    {
+        eventObj->inHotSprings = 0;
+    }
+}
+
+void GetGroundEffectFlags_Seaweed(struct MapObject *eventObj, u32 *flags)
+{
+    if (MetatileBehavior_IsSeaweed(eventObj->currentMetatileBehavior))
+        *flags |= GROUND_EFFECT_FLAG_SEAWEED;
+}
+
+void GetGroundEffectFlags_JumpLanding(struct MapObject *eventObj, u32 *flags)
+{
+    typedef bool8 (*MetatileFunc)(u8);
+
+    static const MetatileFunc metatileFuncs[] = {
+        MetatileBehavior_IsTallGrass,
+        MetatileBehavior_IsLongGrass,
+        MetatileBehavior_IsPuddle,
+        MetatileBehavior_IsSurfableWaterOrUnderwater,
+        MetatileBehavior_IsShallowFlowingWater,
+        MetatileBehavior_IsATile,
+    };
+
+    static const u32 jumpLandingFlags[] = {
+        GROUND_EFFECT_FLAG_LAND_IN_TALL_GRASS,
+        GROUND_EFFECT_FLAG_LAND_IN_LONG_GRASS,
+        GROUND_EFFECT_FLAG_LAND_IN_SHALLOW_WATER,
+        GROUND_EFFECT_FLAG_LAND_IN_DEEP_WATER,
+        GROUND_EFFECT_FLAG_LAND_IN_SHALLOW_WATER,
+        GROUND_EFFECT_FLAG_LAND_ON_NORMAL_GROUND,
+    };
+
+    if (eventObj->landingJump && !eventObj->disableJumpLandingGroundEffect)
+    {
+        u8 i;
+
+        for (i = 0; i < ARRAY_COUNT(metatileFuncs); i++)
+        {
+            if (metatileFuncs[i](eventObj->currentMetatileBehavior))
+            {
+                *flags |= jumpLandingFlags[i];
+                return;
+            }
+        }
+    }
+}
+
+u8 FieldObjectCheckForReflectiveSurface(struct MapObject *eventObj)
+{
+    const struct MapObjectGraphicsInfo *info = GetFieldObjectGraphicsInfo(eventObj->graphicsId);
+
+    // ceil div by tile width?
+    s16 width = (info->width + 8) >> 4;
+    s16 height = (info->height + 8) >> 4;
+    s16 i;
+    s16 j;
+    u8 result;
+    u8 b;
+    s16 one;
+
+#define RETURN_REFLECTION_TYPE_AT(x, y)              \
+    b = MapGridGetMetatileBehaviorAt(x, y);          \
+    result = GetReflectionTypeByMetatileBehavior(b); \
+    if (result != 0)                                 \
+        return result;
+
+    for (i = 0, one = 1; i < height; i++)
+    {
+        RETURN_REFLECTION_TYPE_AT(eventObj->currentCoords.x, eventObj->currentCoords.y + one + i)
+        RETURN_REFLECTION_TYPE_AT(eventObj->previousCoords.x, eventObj->previousCoords.y + one + i)
+        for (j = 1; j < width; j++)
+        {
+            RETURN_REFLECTION_TYPE_AT(eventObj->currentCoords.x + j, eventObj->currentCoords.y + one + i)
+            RETURN_REFLECTION_TYPE_AT(eventObj->currentCoords.x - j, eventObj->currentCoords.y + one + i)
+            RETURN_REFLECTION_TYPE_AT(eventObj->previousCoords.x + j, eventObj->previousCoords.y + one + i)
+            RETURN_REFLECTION_TYPE_AT(eventObj->previousCoords.x - j, eventObj->previousCoords.y + one + i)
+        }
+    }
+    return 0;
+
+#undef RETURN_REFLECTION_TYPE_AT
+}
+
+static u8 GetReflectionTypeByMetatileBehavior(u32 behavior)
+{
+    if (MetatileBehavior_IsIce(behavior))
+        return 1;
+    else if (MetatileBehavior_IsReflective(behavior))
+        return 2;
+    else
+        return 0;
+}
+
+u8 GetLedgeJumpDirection(s16 x, s16 y, u8 z)
+{
+    static bool8 (*const unknown_08376040[])(u8) = {
+        MetatileBehavior_IsJumpSouth,
+        MetatileBehavior_IsJumpNorth,
+        MetatileBehavior_IsJumpWest,
+        MetatileBehavior_IsJumpEast,
+    };
+
+    u8 b;
+    u8 index = z;
+
+    if (index == 0)
+        return 0;
+    else if (index > 4)
+        index -= 4;
+
+    index--;
+    b = MapGridGetMetatileBehaviorAt(x, y);
+
+    if (unknown_08376040[index](b) == 1)
+        return index + 1;
+
+    return 0;
+}
+
+void FieldObjectSetSpriteOamTableForLongGrass(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    if (eventObj->disableCoveringGroundEffects)
+        return;
+
+    if (!MetatileBehavior_IsLongGrass(eventObj->currentMetatileBehavior))
+        return;
+
+    if (!MetatileBehavior_IsLongGrass(eventObj->previousMetatileBehavior))
+        return;
+
+    sprite->subspriteTableNum = 4;
+
+    if (ZCoordToPriority(eventObj->previousElevation) == 1)
+        sprite->subspriteTableNum = 5;
+}
+
+bool8 IsZCoordMismatchAt(u8 z, s16 x, s16 y)
+{
+    u8 mapZ;
+
+    if (z == 0)
+        return FALSE;
+
+    mapZ = MapGridGetZCoordAt(x, y);
+
+    if (mapZ == 0 || mapZ == 0xF)
+        return FALSE;
+
+    if (mapZ != z)
+        return TRUE;
+
+    return FALSE;
+}
+
+static const u8 sUnknown_08376050[] = {
+    0x73, 0x73, 0x53, 0x73, 0x53, 0x73, 0x53, 0x73, 0x53, 0x73, 0x53, 0x73, 0x53, 0x00, 0x00, 0x73
+};
+
+// Each byte corresponds to a sprite priority for an event object.
+// This is directly the inverse of gEventObjectPriorities_08376070.
+static const u8 sEventObjectPriorities_08376060[] = {
+    2, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 0, 0, 2
+};
+
+// Each byte corresponds to a sprite priority for an event object.
+// This is the inverse of gEventObjectPriorities_08376060.
+// 1 = Above player sprite
+// 2 = Below player sprite
+static const u8 sEventObjectPriorities_08376070[] = {
+    1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 0, 0, 1,
+};
+
+void FieldObjectUpdateZCoordAndPriority(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    if (eventObj->fixedPriority)
+        return;
+
+    FieldObjectUpdateZCoord(eventObj);
+
+    sprite->subspriteTableNum = sEventObjectPriorities_08376070[eventObj->previousElevation];
+    sprite->oam.priority = sEventObjectPriorities_08376060[eventObj->previousElevation];
+}
+
+static void InitObjectPriorityByZCoord(struct Sprite *sprite, u8 z)
+{
+    sprite->subspriteTableNum = sEventObjectPriorities_08376070[z];
+    sprite->oam.priority = sEventObjectPriorities_08376060[z];
+}
+
+u8 ZCoordToPriority(u8 z)
+{
+    return sEventObjectPriorities_08376060[z];
+}
+
+void FieldObjectUpdateZCoord(struct MapObject *eventObj)
+{
+    u8 z = MapGridGetZCoordAt(eventObj->currentCoords.x, eventObj->currentCoords.y);
+    u8 z2 = MapGridGetZCoordAt(eventObj->previousCoords.x, eventObj->previousCoords.y);
+
+    if (z == 0xF || z2 == 0xF)
+        return;
+
+    eventObj->currentElevation = z;
+
+    if (z != 0 && z != 0xF)
+        eventObj->previousElevation = z;
+}
+
+void SetObjectSubpriorityByZCoord(u8 a, struct Sprite *sprite, u8 b)
+{
+    s32 tmp = sprite->centerToCornerVecY;
+    u32 tmpa = *(u16 *)&sprite->pos1.y;
+    u32 tmpb = *(u16 *)&gSpriteCoordOffsetY;
+    s32 tmp2 = (tmpa - tmp) + tmpb;
+    u16 tmp3 = (0x10 - ((((u32)tmp2 + 8) & 0xFF) >> 4)) * 2;
+    sprite->subpriority = tmp3 + sUnknown_08376050[a] + b;
+}
+
+static void FieldObjectUpdateSubpriority(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    if (eventObj->fixedPriority)
+        return;
+
+    SetObjectSubpriorityByZCoord(eventObj->previousElevation, sprite, 1);
+}
+
+bool8 AreZCoordsCompatible(u8 a, u8 b)
+{
+    if (a == 0 || b == 0)
+        return TRUE;
+
+    if (a != b)
+        return FALSE;
+
+    return TRUE;
+}
+
+void GroundEffect_SpawnOnTallGrass(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    gFieldEffectArguments[0] = eventObj->currentCoords.x;
+    gFieldEffectArguments[1] = eventObj->currentCoords.y;
+    gFieldEffectArguments[2] = eventObj->previousElevation;
+    gFieldEffectArguments[3] = 2;
+    gFieldEffectArguments[4] = eventObj->localId << 8 | eventObj->mapNum;
+    gFieldEffectArguments[5] = eventObj->mapGroup;
+    gFieldEffectArguments[6] = (u8)gSaveBlock1Ptr->location.mapNum << 8 | (u8)gSaveBlock1Ptr->location.mapGroup;
+    gFieldEffectArguments[7] = 1;
+    FieldEffectStart(FLDEFF_TALL_GRASS);
+}
+
+void GroundEffect_StepOnTallGrass(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    gFieldEffectArguments[0] = eventObj->currentCoords.x;
+    gFieldEffectArguments[1] = eventObj->currentCoords.y;
+    gFieldEffectArguments[2] = eventObj->previousElevation;
+    gFieldEffectArguments[3] = 2;
+    gFieldEffectArguments[4] = eventObj->localId << 8 | eventObj->mapNum;
+    gFieldEffectArguments[5] = eventObj->mapGroup;
+    gFieldEffectArguments[6] = (u8)gSaveBlock1Ptr->location.mapNum << 8 | (u8)gSaveBlock1Ptr->location.mapGroup;
+    gFieldEffectArguments[7] = 0;
+    FieldEffectStart(FLDEFF_TALL_GRASS);
+}
+
+void GroundEffect_SpawnOnLongGrass(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    gFieldEffectArguments[0] = eventObj->currentCoords.x;
+    gFieldEffectArguments[1] = eventObj->currentCoords.y;
+    gFieldEffectArguments[2] = eventObj->previousElevation;
+    gFieldEffectArguments[3] = 2;
+    gFieldEffectArguments[4] = eventObj->localId << 8 | eventObj->mapNum;
+    gFieldEffectArguments[5] = eventObj->mapGroup;
+    gFieldEffectArguments[6] = (u8)gSaveBlock1Ptr->location.mapNum << 8 | (u8)gSaveBlock1Ptr->location.mapGroup;
+    gFieldEffectArguments[7] = 1;
+    FieldEffectStart(FLDEFF_LONG_GRASS);
+}
+
+void GroundEffect_StepOnLongGrass(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    gFieldEffectArguments[0] = eventObj->currentCoords.x;
+    gFieldEffectArguments[1] = eventObj->currentCoords.y;
+    gFieldEffectArguments[2] = eventObj->previousElevation;
+    gFieldEffectArguments[3] = 2;
+    gFieldEffectArguments[4] = (eventObj->localId << 8) | eventObj->mapNum;
+    gFieldEffectArguments[5] = eventObj->mapGroup;
+    gFieldEffectArguments[6] = (u8)gSaveBlock1Ptr->location.mapNum << 8 | (u8)gSaveBlock1Ptr->location.mapGroup;
+    gFieldEffectArguments[7] = 0;
+    FieldEffectStart(FLDEFF_LONG_GRASS);
+}
+
+void GroundEffect_WaterReflection(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    SetUpReflection(eventObj, sprite, 0);
+}
+
+void GroundEffect_IceReflection(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    SetUpReflection(eventObj, sprite, 1);
+}
+
+void GroundEffect_FlowingWater(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    StartFieldEffectForEventObject(FLDEFF_FEET_IN_FLOWING_WATER, eventObj);
+}
+
+static void (*const sGroundEffectTracksFuncs[])(struct MapObject *eventObj, struct Sprite *sprite, u8 a) = {
+    DoTracksGroundEffect_None,
+    DoTracksGroundEffect_Footprints,
+    DoTracksGroundEffect_BikeTireTracks,
+};
+
+void GroundEffect_SandTracks(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    const struct MapObjectGraphicsInfo *info = GetFieldObjectGraphicsInfo(eventObj->graphicsId);
+    sGroundEffectTracksFuncs[info->tracks](eventObj, sprite, 0);
+}
+
+void GroundEffect_DeepSandTracks(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    const struct MapObjectGraphicsInfo *info = GetFieldObjectGraphicsInfo(eventObj->graphicsId);
+    sGroundEffectTracksFuncs[info->tracks](eventObj, sprite, 1);
+}
+
+static void DoTracksGroundEffect_None(struct MapObject *eventObj, struct Sprite *sprite, u8 a)
+{
+}
+
+static void DoTracksGroundEffect_Footprints(struct MapObject *eventObj, struct Sprite *sprite, u8 a)
+{
+    // First half-word is a Field Effect script id. (gFieldEffectScriptPointers)
+    u16 sandFootprints_FieldEffectData[2] = {
+        FLDEFF_SAND_FOOTPRINTS,
+        FLDEFF_DEEP_SAND_FOOTPRINTS
+    };
+
+    gFieldEffectArguments[0] = eventObj->previousCoords.x;
+    gFieldEffectArguments[1] = eventObj->previousCoords.y;
+    gFieldEffectArguments[2] = 149;
+    gFieldEffectArguments[3] = 2;
+    gFieldEffectArguments[4] = eventObj->facingDirection;
+    FieldEffectStart(sandFootprints_FieldEffectData[a]);
+}
+
+static void DoTracksGroundEffect_BikeTireTracks(struct MapObject *eventObj, struct Sprite *sprite, u8 a)
+{
+    //  Specifies which bike track shape to show next.
+    //  For example, when the bike turns from up to right, it will show
+    //  a track that curves to the right.
+    //  Each 4-byte row corresponds to the initial direction of the bike, and
+    //  each byte in that row is for the next direction of the bike in the order
+    //  of down, up, left, right.
+    static const u8 bikeTireTracks_Transitions[4][4] = {
+        1, 2, 7, 8,
+        1, 2, 6, 5,
+        5, 8, 3, 4,
+        6, 7, 3, 4,
+    };
+
+    if (eventObj->currentCoords.x != eventObj->previousCoords.x || eventObj->currentCoords.y != eventObj->previousCoords.y)
+    {
+        gFieldEffectArguments[0] = eventObj->previousCoords.x;
+        gFieldEffectArguments[1] = eventObj->previousCoords.y;
+        gFieldEffectArguments[2] = 149;
+        gFieldEffectArguments[3] = 2;
+        gFieldEffectArguments[4] =
+            bikeTireTracks_Transitions[eventObj->previousMovementDirection][eventObj->facingDirection - 5];
+        FieldEffectStart(FLDEFF_BIKE_TIRE_TRACKS);
+    }
+}
+
+void GroundEffect_Ripple(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    DoRippleFieldEffect(eventObj, sprite);
+}
+
+void GroundEffect_StepOnPuddle(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    StartFieldEffectForEventObject(FLDEFF_SPLASH, eventObj);
+}
+
+void GroundEffect_SandHeap(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    StartFieldEffectForEventObject(FLDEFF_SAND_PILE, eventObj);
+}
+
+void GroundEffect_JumpOnTallGrass(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    u8 spriteId;
+
+    gFieldEffectArguments[0] = eventObj->currentCoords.x;
+    gFieldEffectArguments[1] = eventObj->currentCoords.y;
+    gFieldEffectArguments[2] = eventObj->previousElevation;
+    gFieldEffectArguments[3] = 2;
+    FieldEffectStart(FLDEFF_JUMP_TALL_GRASS);
+
+    spriteId = sub_81546C8(
+        eventObj->localId, eventObj->mapNum, eventObj->mapGroup, eventObj->currentCoords.x, eventObj->currentCoords.y);
+
+    if (spriteId == MAX_SPRITES)
+        GroundEffect_SpawnOnTallGrass(eventObj, sprite);
+}
+
+void GroundEffect_JumpOnLongGrass(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    gFieldEffectArguments[0] = eventObj->currentCoords.x;
+    gFieldEffectArguments[1] = eventObj->currentCoords.y;
+    gFieldEffectArguments[2] = eventObj->previousElevation;
+    gFieldEffectArguments[3] = 2;
+    FieldEffectStart(FLDEFF_JUMP_LONG_GRASS);
+}
+
+void GroundEffect_JumpOnShallowWater(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    gFieldEffectArguments[0] = eventObj->currentCoords.x;
+    gFieldEffectArguments[1] = eventObj->currentCoords.y;
+    gFieldEffectArguments[2] = eventObj->previousElevation;
+    gFieldEffectArguments[3] = sprite->oam.priority;
+    FieldEffectStart(FLDEFF_JUMP_SMALL_SPLASH);
+}
+
+void GroundEffect_JumpOnWater(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    gFieldEffectArguments[0] = eventObj->currentCoords.x;
+    gFieldEffectArguments[1] = eventObj->currentCoords.y;
+    gFieldEffectArguments[2] = eventObj->previousElevation;
+    gFieldEffectArguments[3] = sprite->oam.priority;
+    FieldEffectStart(FLDEFF_JUMP_BIG_SPLASH);
+}
+
+void GroundEffect_JumpLandingDust(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    gFieldEffectArguments[0] = eventObj->currentCoords.x;
+    gFieldEffectArguments[1] = eventObj->currentCoords.y;
+    gFieldEffectArguments[2] = eventObj->previousElevation;
+    gFieldEffectArguments[3] = sprite->oam.priority;
+    FieldEffectStart(FLDEFF_DUST);
+}
+
+void GroundEffect_ShortGrass(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    StartFieldEffectForEventObject(FLDEFF_SHORT_GRASS, eventObj);
+}
+
+void GroundEffect_HotSprings(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    StartFieldEffectForEventObject(FLDEFF_HOT_SPRINGS_WATER, eventObj);
+}
+
+void GroundEffect_Seaweed(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    gFieldEffectArguments[0] = eventObj->currentCoords.x;
+    gFieldEffectArguments[1] = eventObj->currentCoords.y;
+    FieldEffectStart(FLDEFF_BUBBLES);
+}
+
+static void (*const sGroundEffectFuncs[])(struct MapObject *eventObj, struct Sprite *sprite) = {
+    GroundEffect_SpawnOnTallGrass,
+    GroundEffect_StepOnTallGrass,
+    GroundEffect_SpawnOnLongGrass,
+    GroundEffect_StepOnLongGrass,
+    GroundEffect_WaterReflection,
+    GroundEffect_IceReflection,
+    GroundEffect_FlowingWater,
+    GroundEffect_SandTracks,
+    GroundEffect_DeepSandTracks,
+    GroundEffect_Ripple,
+    GroundEffect_StepOnPuddle,
+    GroundEffect_SandHeap,
+    GroundEffect_JumpOnTallGrass,
+    GroundEffect_JumpOnLongGrass,
+    GroundEffect_JumpOnShallowWater,
+    GroundEffect_JumpOnWater,
+    GroundEffect_JumpLandingDust,
+    GroundEffect_ShortGrass,
+    GroundEffect_HotSprings,
+    GroundEffect_Seaweed
+};
+
+/*static*/ void DoFlaggedGroundEffects(struct MapObject *eventObj, struct Sprite *sprite, u32 flags)
+{
+    u8 i;
+
+    if (FieldObjectIsFarawayIslandMew(eventObj) == TRUE && !sub_81D4A58(eventObj))
+        return;
+
+    for (i = 0; i < ARRAY_COUNT(sGroundEffectFuncs); i++, flags >>= 1)
+        if (flags & 1)
+            sGroundEffectFuncs[i](eventObj, sprite);
+}
+
+void filters_out_some_ground_effects(struct MapObject *eventObj, u32 *flags)
+{
+    if (eventObj->disableCoveringGroundEffects)
+    {
+        eventObj->inShortGrass = 0;
+        eventObj->inSandPile = 0;
+        eventObj->inShallowFlowingWater = 0;
+        eventObj->inHotSprings = 0;
+        *flags &= ~(GROUND_EFFECT_FLAG_HOT_SPRINGS
+                  | GROUND_EFFECT_FLAG_SHORT_GRASS
+                  | GROUND_EFFECT_FLAG_SAND_PILE
+                  | GROUND_EFFECT_FLAG_SHALLOW_FLOWING_WATER
+                  | GROUND_EFFECT_FLAG_TALL_GRASS_ON_MOVE);
+    }
+}
+
+void FilterOutStepOnPuddleGroundEffectIfJumping(struct MapObject *eventObj, u32 *flags)
+{
+    if (eventObj->landingJump)
+        *flags &= ~GROUND_EFFECT_FLAG_PUDDLE;
+}
+
+static void DoGroundEffects_OnSpawn(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    u32 flags;
+
+    if (eventObj->triggerGroundEffectsOnMove)
+    {
+        flags = 0;
+        FieldObjectUpdateZCoordAndPriority(eventObj, sprite);
+        GetAllGroundEffectFlags_OnSpawn(eventObj, &flags);
+        FieldObjectSetSpriteOamTableForLongGrass(eventObj, sprite);
+        DoFlaggedGroundEffects(eventObj, sprite, flags);
+        eventObj->triggerGroundEffectsOnMove = 0;
+        eventObj->disableCoveringGroundEffects = 0;
+    }
+}
+
+static void DoGroundEffects_OnBeginStep(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    u32 flags;
+
+    if (eventObj->triggerGroundEffectsOnMove)
+    {
+        flags = 0;
+        FieldObjectUpdateZCoordAndPriority(eventObj, sprite);
+        GetAllGroundEffectFlags_OnBeginStep(eventObj, &flags);
+        FieldObjectSetSpriteOamTableForLongGrass(eventObj, sprite);
+        filters_out_some_ground_effects(eventObj, &flags);
+        DoFlaggedGroundEffects(eventObj, sprite, flags);
+        eventObj->triggerGroundEffectsOnMove = 0;
+        eventObj->disableCoveringGroundEffects = 0;
+    }
+}
+
+static void DoGroundEffects_OnFinishStep(struct MapObject *eventObj, struct Sprite *sprite)
+{
+    u32 flags;
+
+    if (eventObj->triggerGroundEffectsOnStop)
+    {
+        flags = 0;
+        FieldObjectUpdateZCoordAndPriority(eventObj, sprite);
+        GetAllGroundEffectFlags_OnFinishStep(eventObj, &flags);
+        FieldObjectSetSpriteOamTableForLongGrass(eventObj, sprite);
+        FilterOutStepOnPuddleGroundEffectIfJumping(eventObj, &flags);
+        DoFlaggedGroundEffects(eventObj, sprite, flags);
+        eventObj->triggerGroundEffectsOnStop = 0;
+        eventObj->landingJump = 0;
+    }
+}
diff --git a/src/event_object_movement_helpers.c b/src/event_object_movement_helpers.c
index 660c8961a..6a8b410f5 100755
--- a/src/event_object_movement_helpers.c
+++ b/src/event_object_movement_helpers.c
@@ -1,5 +1,4 @@
 #include "global.h"
-#include "field_ground_effect.h"
 #include "event_object_movement.h"
 #include "field_effect.h"
 #include "event_object_movement_helpers.h"
@@ -504,7 +503,7 @@ bool32 sub_8097D9C(u8 var)
     return FALSE;
 }
 
-u32 oe_exec_and_other_stuff(u8 fieldEffectId, struct MapObject *mapObject)
+u32 StartFieldEffectForEventObject(u8 fieldEffectId, struct MapObject *mapObject)
 {
     FieldObjectGetLocalIdAndMap(mapObject, &gFieldEffectArguments[0], &gFieldEffectArguments[1], &gFieldEffectArguments[2]);
     return FieldEffectStart(fieldEffectId);
@@ -515,7 +514,7 @@ void DoShadowFieldEffect(struct MapObject *mapObject)
     if (!mapObject->hasShadow)
     {
         mapObject->hasShadow = 1;
-        oe_exec_and_other_stuff(FLDEFF_SHADOW, mapObject);
+        StartFieldEffectForEventObject(FLDEFF_SHADOW, mapObject);
     }
 }
 
diff --git a/src/metatile_behavior.c b/src/metatile_behavior.c
index b9760f522..ad0062c20 100644
--- a/src/metatile_behavior.c
+++ b/src/metatile_behavior.c
@@ -252,8 +252,7 @@ static const u8 sTileBitAttributes[] =
     TILE_ATTRIBUTES(FALSE, FALSE, FALSE), // ? 0xEF
 };
 
-// only used as default case for checking jump landing in field_ground_effect.
-bool8 ShouldDoJumpLandingDustEffect(u8 var)
+bool8 MetatileBehavior_IsATile(u8 var)
 {
     return TRUE;
 }
diff --git a/src/overworld.c b/src/overworld.c
index 3279ce4fb..045ebb4fd 100644
--- a/src/overworld.c
+++ b/src/overworld.c
@@ -10,7 +10,6 @@
 #include "field_control_avatar.h"
 #include "field_effect.h"
 #include "field_fadetransition.h"
-#include "field_ground_effect.h"
 #include "event_object_movement.h"
 #include "event_object_movement_helpers.h"
 #include "field_message_box.h"