Merge pull request #294 from PikalaxALT/fldeff_flash

fldeff_flash.c

20 files changed, 639 insertions, 1178 deletions

diff --git a/asm/fldeff_flash.s b/asm/fldeff_flash.s
deleted file mode 100644
index c6cc17f82..000000000
--- a/asm/fldeff_flash.s
+++ /dev/null
@@ -1,964 +0,0 @@
-	.include "asm/macros.inc"
-	.include "constants/constants.inc"
-
-	.syntax unified
-
-	.text
-
-	thumb_func_start SetUpFieldMove_Flash
-SetUpFieldMove_Flash: @ 80C9B2C
-	push {lr}
-	ldr r0, _080C9B54 @ =gMapHeader
-	ldrb r0, [r0, 0x15]
-	cmp r0, 0x1
-	bne _080C9B6C
-	ldr r0, _080C9B58 @ =0x00000806
-	bl FlagGet
-	lsls r0, 24
-	cmp r0, 0
-	bne _080C9B6C
-	ldr r1, _080C9B5C @ =gFieldCallback2
-	ldr r0, _080C9B60 @ =FieldCallback_PrepareFadeInFromMenu
-	str r0, [r1]
-	ldr r1, _080C9B64 @ =gPostMenuFieldCallback
-	ldr r0, _080C9B68 @ =sub_80C9B74
-	str r0, [r1]
-	movs r0, 0x1
-	b _080C9B6E
-	.align 2, 0
-_080C9B54: .4byte gMapHeader
-_080C9B58: .4byte 0x00000806
-_080C9B5C: .4byte gFieldCallback2
-_080C9B60: .4byte FieldCallback_PrepareFadeInFromMenu
-_080C9B64: .4byte gPostMenuFieldCallback
-_080C9B68: .4byte sub_80C9B74
-_080C9B6C:
-	movs r0, 0
-_080C9B6E:
-	pop {r1}
-	bx r1
-	thumb_func_end SetUpFieldMove_Flash
-
-	thumb_func_start sub_80C9B74
-sub_80C9B74: @ 80C9B74
-	push {r4,lr}
-	bl CreateFieldEffectShowMon
-	adds r4, r0, 0
-	lsls r4, 24
-	lsrs r4, 24
-	bl GetCursorSelectionMonId
-	ldr r1, _080C9BA4 @ =gFieldEffectArguments
-	lsls r0, 24
-	lsrs r0, 24
-	str r0, [r1]
-	ldr r1, _080C9BA8 @ =gTasks
-	lsls r0, r4, 2
-	adds r0, r4
-	lsls r0, 3
-	adds r0, r1
-	ldr r2, _080C9BAC @ =sub_80C9BB0
-	lsrs r1, r2, 16
-	strh r1, [r0, 0x18]
-	strh r2, [r0, 0x1A]
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9BA4: .4byte gFieldEffectArguments
-_080C9BA8: .4byte gTasks
-_080C9BAC: .4byte sub_80C9BB0
-	thumb_func_end sub_80C9B74
-
-	thumb_func_start sub_80C9BB0
-sub_80C9BB0: @ 80C9BB0
-	push {lr}
-	movs r0, 0xC8
-	bl PlaySE
-	ldr r0, _080C9BC8 @ =0x00000806
-	bl FlagSet
-	ldr r0, _080C9BCC @ =EventScript_FldEffFlash
-	bl ScriptContext1_SetupScript
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9BC8: .4byte 0x00000806
-_080C9BCC: .4byte EventScript_FldEffFlash
-	thumb_func_end sub_80C9BB0
-
-	thumb_func_start sub_80C9BD0
-sub_80C9BD0: @ 80C9BD0
-	push {lr}
-	bl RunTasks
-	bl AnimateSprites
-	bl BuildOamBuffer
-	bl UpdatePaletteFade
-	pop {r0}
-	bx r0
-	thumb_func_end sub_80C9BD0
-
-	thumb_func_start sub_80C9BE8
-sub_80C9BE8: @ 80C9BE8
-	push {lr}
-	bl LoadOam
-	bl ProcessSpriteCopyRequests
-	bl TransferPlttBuffer
-	pop {r0}
-	bx r0
-	thumb_func_end sub_80C9BE8
-
-	thumb_func_start sub_80C9BFC
-sub_80C9BFC: @ 80C9BFC
-	push {lr}
-	sub sp, 0x8
-	movs r0, 0
-	bl SetVBlankCallback
-	movs r0, 0
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0xC
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0xA
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x8
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x18
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x1A
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x14
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x16
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x10
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x12
-	movs r1, 0
-	bl SetGpuReg
-	mov r1, sp
-	movs r0, 0
-	strh r0, [r1]
-	ldr r1, _080C9CC8 @ =0x040000d4
-	mov r0, sp
-	str r0, [r1]
-	movs r0, 0xC0
-	lsls r0, 19
-	str r0, [r1, 0x4]
-	ldr r0, _080C9CCC @ =0x8100c000
-	str r0, [r1, 0x8]
-	ldr r0, [r1, 0x8]
-	movs r2, 0
-	str r2, [sp, 0x4]
-	add r0, sp, 0x4
-	str r0, [r1]
-	movs r0, 0xE0
-	lsls r0, 19
-	str r0, [r1, 0x4]
-	ldr r0, _080C9CD0 @ =0x85000100
-	str r0, [r1, 0x8]
-	ldr r0, [r1, 0x8]
-	mov r0, sp
-	strh r2, [r0]
-	str r0, [r1]
-	ldr r0, _080C9CD4 @ =0x05000002
-	str r0, [r1, 0x4]
-	ldr r0, _080C9CD8 @ =0x810001ff
-	str r0, [r1, 0x8]
-	ldr r0, [r1, 0x8]
-	bl ResetPaletteFade
-	bl ResetTasks
-	bl ResetSpriteData
-	movs r0, 0x1
-	bl EnableInterrupts
-	ldr r0, _080C9CDC @ =sub_80C9BE8
-	bl SetVBlankCallback
-	ldr r0, _080C9CE0 @ =sub_80C9BD0
-	bl SetMainCallback2
-	bl sub_80C9CE8
-	lsls r0, 24
-	cmp r0, 0
-	bne _080C9CC2
-	ldr r0, _080C9CE4 @ =gMain
-	ldr r0, [r0, 0x8]
-	bl SetMainCallback2
-_080C9CC2:
-	add sp, 0x8
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9CC8: .4byte 0x040000d4
-_080C9CCC: .4byte 0x8100c000
-_080C9CD0: .4byte 0x85000100
-_080C9CD4: .4byte 0x05000002
-_080C9CD8: .4byte 0x810001ff
-_080C9CDC: .4byte sub_80C9BE8
-_080C9CE0: .4byte sub_80C9BD0
-_080C9CE4: .4byte gMain
-	thumb_func_end sub_80C9BFC
-
-	thumb_func_start sub_80C9CE8
-sub_80C9CE8: @ 80C9CE8
-	push {r4-r7,lr}
-	bl get_map_light_from_warp0
-	lsls r0, 24
-	lsrs r7, r0, 24
-	bl GetCurrentMapType
-	lsls r0, 24
-	lsrs r6, r0, 24
-	movs r4, 0
-	bl sub_80561B4
-	ldr r5, _080C9D24 @ =gMapHeader
-	lsls r0, 24
-	lsrs r0, 24
-	ldrb r1, [r5, 0x14]
-	cmp r0, r1
-	beq _080C9D36
-	ldrb r0, [r5, 0x14]
-	movs r1, 0
-	bl sub_80F8154
-	cmp r0, 0x1
-	bne _080C9D36
-	ldrb r0, [r5, 0x14]
-	bl sub_80CA160
-	movs r0, 0x1
-	b _080C9D70
-	.align 2, 0
-_080C9D24: .4byte gMapHeader
-_080C9D28:
-	adds r0, r3, 0x4
-	adds r0, r2, r0
-	ldr r0, [r0]
-	bl _call_via_r0
-	movs r0, 0x1
-	b _080C9D70
-_080C9D36:
-	ldr r5, _080C9D78 @ =gUnknown_83F5738
-	lsls r1, r4, 1
-	adds r0, r1, r4
-	lsls r0, 2
-	adds r0, r5
-	ldrb r0, [r0]
-	cmp r0, 0
-	beq _080C9D6E
-	adds r3, r5, 0
-_080C9D48:
-	adds r0, r1, r4
-	lsls r2, r0, 2
-	adds r1, r2, r3
-	ldrb r0, [r1]
-	cmp r0, r7
-	bne _080C9D5A
-	ldrb r0, [r1, 0x1]
-	cmp r0, r6
-	beq _080C9D28
-_080C9D5A:
-	adds r0, r4, 0x1
-	lsls r0, 24
-	lsrs r4, r0, 24
-	lsls r1, r4, 1
-	adds r0, r1, r4
-	lsls r0, 2
-	adds r0, r5
-	ldrb r0, [r0]
-	cmp r0, 0
-	bne _080C9D48
-_080C9D6E:
-	movs r0, 0
-_080C9D70:
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	.align 2, 0
-_080C9D78: .4byte gUnknown_83F5738
-	thumb_func_end sub_80C9CE8
-
-	thumb_func_start sub_80C9D7C
-sub_80C9D7C: @ 80C9D7C
-	push {r4-r6,lr}
-	lsls r0, 24
-	lsls r1, 24
-	lsrs r5, r0, 24
-	lsrs r4, r1, 24
-	movs r3, 0
-	ldr r1, _080C9DAC @ =gUnknown_83F5738
-	ldrb r0, [r1]
-	cmp r0, 0
-	beq _080C9DC4
-	adds r6, r1, 0
-_080C9D92:
-	lsls r0, r3, 1
-	adds r0, r3
-	lsls r0, 2
-	adds r2, r0, r6
-	ldrb r0, [r2]
-	cmp r0, r5
-	bne _080C9DB0
-	ldrb r0, [r2, 0x1]
-	cmp r0, r4
-	bne _080C9DB0
-	ldrb r0, [r2, 0x2]
-	b _080C9DC6
-	.align 2, 0
-_080C9DAC: .4byte gUnknown_83F5738
-_080C9DB0:
-	adds r0, r3, 0x1
-	lsls r0, 24
-	lsrs r3, r0, 24
-	lsls r0, r3, 1
-	adds r0, r3
-	lsls r0, 2
-	adds r0, r1
-	ldrb r0, [r0]
-	cmp r0, 0
-	bne _080C9D92
-_080C9DC4:
-	movs r0, 0
-_080C9DC6:
-	pop {r4-r6}
-	pop {r1}
-	bx r1
-	thumb_func_end sub_80C9D7C
-
-	thumb_func_start sub_80C9DCC
-sub_80C9DCC: @ 80C9DCC
-	push {r4-r6,lr}
-	lsls r0, 24
-	lsls r1, 24
-	lsrs r5, r0, 24
-	lsrs r4, r1, 24
-	movs r3, 0
-	ldr r1, _080C9DFC @ =gUnknown_83F5738
-	ldrb r0, [r1]
-	cmp r0, 0
-	beq _080C9E14
-	adds r6, r1, 0
-_080C9DE2:
-	lsls r0, r3, 1
-	adds r0, r3
-	lsls r0, 2
-	adds r2, r0, r6
-	ldrb r0, [r2]
-	cmp r0, r5
-	bne _080C9E00
-	ldrb r0, [r2, 0x1]
-	cmp r0, r4
-	bne _080C9E00
-	ldrb r0, [r2, 0x3]
-	b _080C9E16
-	.align 2, 0
-_080C9DFC: .4byte gUnknown_83F5738
-_080C9E00:
-	adds r0, r3, 0x1
-	lsls r0, 24
-	lsrs r3, r0, 24
-	lsls r0, r3, 1
-	adds r0, r3
-	lsls r0, 2
-	adds r0, r1
-	ldrb r0, [r0]
-	cmp r0, 0
-	bne _080C9DE2
-_080C9E14:
-	movs r0, 0
-_080C9E16:
-	pop {r4-r6}
-	pop {r1}
-	bx r1
-	thumb_func_end sub_80C9DCC
-
-	thumb_func_start sub_80C9E1C
-sub_80C9E1C: @ 80C9E1C
-	push {lr}
-	ldr r0, _080C9E2C @ =sub_80C9E30
-	movs r1, 0
-	bl CreateTask
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9E2C: .4byte sub_80C9E30
-	thumb_func_end sub_80C9E1C
-
-	thumb_func_start sub_80C9E30
-sub_80C9E30: @ 80C9E30
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080C9E44 @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r1, r2
-	ldr r0, _080C9E48 @ =sub_80C9E4C
-	str r0, [r1]
-	bx lr
-	.align 2, 0
-_080C9E44: .4byte gTasks
-_080C9E48: .4byte sub_80C9E4C
-	thumb_func_end sub_80C9E30
-
-	thumb_func_start sub_80C9E4C
-sub_80C9E4C: @ 80C9E4C
-	push {r4,lr}
-	adds r4, r0, 0
-	lsls r4, 24
-	lsrs r4, 24
-	movs r0, 0
-	movs r1, 0
-	bl SetGpuReg
-	ldr r0, _080C9EC8 @ =gUnknown_83F5A44
-	ldr r1, _080C9ECC @ =0x0600c000
-	bl LZ77UnCompVram
-	ldr r0, _080C9ED0 @ =gUnknown_83F5864
-	ldr r1, _080C9ED4 @ =0x0600f800
-	bl LZ77UnCompVram
-	ldr r0, _080C9ED8 @ =gUnknown_83F5804
-	movs r1, 0xE0
-	movs r2, 0x20
-	bl LoadPalette
-	ldr r0, _080C9EDC @ =gUnknown_83F5844 + 0x10
-	movs r1, 0xE0
-	movs r2, 0x10
-	bl LoadPalette
-	ldr r1, _080C9EE0 @ =0x00003e41
-	movs r0, 0x50
-	bl SetGpuReg
-	movs r0, 0x52
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x54
-	movs r1, 0
-	bl SetGpuReg
-	ldr r1, _080C9EE4 @ =0x00001f0c =BGCNT_PRIORITY(0) | BGCNT_CHARBASE(3) | BGCNT_SCREENBASE(31)
-	movs r0, 0x8
-	bl SetGpuReg
-	movs r1, 0x8A
-	lsls r1, 5
-	movs r0, 0
-	bl SetGpuReg
-	ldr r1, _080C9EE8 @ =gTasks
-	lsls r0, r4, 2
-	adds r0, r4
-	lsls r0, 3
-	adds r0, r1
-	ldr r1, _080C9EEC @ =sub_80C9EF0
-	str r1, [r0]
-	movs r2, 0
-	movs r1, 0x10
-	strh r1, [r0, 0x8]
-	strh r2, [r0, 0xA]
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9EC8: .4byte gUnknown_83F5A44
-_080C9ECC: .4byte 0x0600c000
-_080C9ED0: .4byte gUnknown_83F5864
-_080C9ED4: .4byte 0x0600f800
-_080C9ED8: .4byte gUnknown_83F5804
-_080C9EDC: .4byte gUnknown_83F5844 + 0x10
-_080C9EE0: .4byte 0x00003e41
-_080C9EE4: .4byte 0x00001f0c
-_080C9EE8: .4byte gTasks
-_080C9EEC: .4byte sub_80C9EF0
-	thumb_func_end sub_80C9E4C
-
-	thumb_func_start sub_80C9EF0
-sub_80C9EF0: @ 80C9EF0
-	push {r4,r5,lr}
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080C9F20 @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r5, r1, r2
-	ldrh r4, [r5, 0xA]
-	movs r0, 0x80
-	lsls r0, 5
-	adds r1, r4, r0
-	lsls r1, 16
-	lsrs r1, 16
-	movs r0, 0x52
-	bl SetGpuReg
-	cmp r4, 0x10
-	bhi _080C9F24
-	ldrh r0, [r5, 0xA]
-	adds r0, 0x1
-	strh r0, [r5, 0xA]
-	b _080C9F2C
-	.align 2, 0
-_080C9F20: .4byte gTasks
-_080C9F24:
-	movs r0, 0
-	strh r0, [r5, 0xC]
-	ldr r0, _080C9F34 @ =sub_80C9F38
-	str r0, [r5]
-_080C9F2C:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9F34: .4byte sub_80C9F38
-	thumb_func_end sub_80C9EF0
-
-	thumb_func_start sub_80C9F38
-sub_80C9F38: @ 80C9F38
-	push {r4,lr}
-	adds r4, r0, 0
-	lsls r4, 24
-	lsrs r4, 24
-	ldr r1, _080C9F74 @ =0x00001010
-	movs r0, 0x52
-	bl SetGpuReg
-	ldr r1, _080C9F78 @ =gTasks
-	lsls r0, r4, 2
-	adds r0, r4
-	lsls r0, 3
-	adds r4, r0, r1
-	ldrh r1, [r4, 0xC]
-	cmp r1, 0x7
-	bhi _080C9F80
-	adds r0, r1, 0x1
-	strh r0, [r4, 0xC]
-	lsls r1, 1
-	ldr r0, _080C9F7C @ =gUnknown_83F5844 + 0x10
-	adds r0, r1, r0
-	movs r2, 0x10
-	subs r2, r1
-	lsls r2, 16
-	lsrs r2, 16
-	movs r1, 0xE0
-	bl LoadPalette
-	b _080C9F92
-	.align 2, 0
-_080C9F74: .4byte 0x00001010
-_080C9F78: .4byte gTasks
-_080C9F7C: .4byte gUnknown_83F5844 + 0x10
-_080C9F80:
-	ldr r0, _080C9F98 @ =gUnknown_83F5804
-	movs r1, 0
-	movs r2, 0x20
-	bl LoadPalette
-	ldr r0, _080C9F9C @ =sub_80C9FA0
-	str r0, [r4]
-	movs r0, 0x8
-	strh r0, [r4, 0xC]
-_080C9F92:
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9F98: .4byte gUnknown_83F5804
-_080C9F9C: .4byte sub_80C9FA0
-	thumb_func_end sub_80C9F38
-
-	thumb_func_start sub_80C9FA0
-sub_80C9FA0: @ 80C9FA0
-	push {lr}
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080C9FC0 @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r1, r2
-	ldrh r2, [r1, 0xC]
-	movs r3, 0xC
-	ldrsh r0, [r1, r3]
-	cmp r0, 0
-	beq _080C9FC4
-	subs r0, r2, 0x1
-	strh r0, [r1, 0xC]
-	b _080C9FCC
-	.align 2, 0
-_080C9FC0: .4byte gTasks
-_080C9FC4:
-	ldr r0, _080C9FD0 @ =gMain
-	ldr r0, [r0, 0x8]
-	bl SetMainCallback2
-_080C9FCC:
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9FD0: .4byte gMain
-	thumb_func_end sub_80C9FA0
-
-	thumb_func_start sub_80C9FD4
-sub_80C9FD4: @ 80C9FD4
-	push {lr}
-	ldr r0, _080C9FE4 @ =sub_80C9FE8
-	movs r1, 0
-	bl CreateTask
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9FE4: .4byte sub_80C9FE8
-	thumb_func_end sub_80C9FD4
-
-	thumb_func_start sub_80C9FE8
-sub_80C9FE8: @ 80C9FE8
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080C9FFC @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r1, r2
-	ldr r0, _080CA000 @ =sub_80CA004
-	str r0, [r1]
-	bx lr
-	.align 2, 0
-_080C9FFC: .4byte gTasks
-_080CA000: .4byte sub_80CA004
-	thumb_func_end sub_80C9FE8
-
-	thumb_func_start sub_80CA004
-sub_80CA004: @ 80CA004
-	push {r4,lr}
-	adds r4, r0, 0
-	lsls r4, 24
-	lsrs r4, 24
-	movs r0, 0
-	movs r1, 0
-	bl SetGpuReg
-	ldr r0, _080CA080 @ =gUnknown_83F5A44
-	ldr r1, _080CA084 @ =0x0600c000
-	bl LZ77UnCompVram
-	ldr r0, _080CA088 @ =gUnknown_83F5864
-	ldr r1, _080CA08C @ =0x0600f800
-	bl LZ77UnCompVram
-	movs r0, 0x50
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x52
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x54
-	movs r1, 0
-	bl SetGpuReg
-	ldr r1, _080CA090 @ =0x00001f0c
-	movs r0, 0x8
-	bl SetGpuReg
-	movs r1, 0x8A
-	lsls r1, 5
-	movs r0, 0
-	bl SetGpuReg
-	ldr r0, _080CA094 @ =gUnknown_83F5804
-	movs r1, 0xE0
-	movs r2, 0x20
-	bl LoadPalette
-	ldr r0, _080CA098 @ =gUnknown_83F5824
-	movs r1, 0
-	movs r2, 0x20
-	bl LoadPalette
-	ldr r1, _080CA09C @ =gTasks
-	lsls r0, r4, 2
-	adds r0, r4
-	lsls r0, 3
-	adds r0, r1
-	ldr r1, _080CA0A0 @ =sub_80CA0A4
-	str r1, [r0]
-	movs r2, 0
-	movs r1, 0x10
-	strh r1, [r0, 0x8]
-	strh r2, [r0, 0xA]
-	strh r2, [r0, 0xC]
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080CA080: .4byte gUnknown_83F5A44
-_080CA084: .4byte 0x0600c000
-_080CA088: .4byte gUnknown_83F5864
-_080CA08C: .4byte 0x0600f800
-_080CA090: .4byte 0x00001f0c
-_080CA094: .4byte gUnknown_83F5804
-_080CA098: .4byte gUnknown_83F5824
-_080CA09C: .4byte gTasks
-_080CA0A0: .4byte sub_80CA0A4
-	thumb_func_end sub_80CA004
-
-	thumb_func_start sub_80CA0A4
-sub_80CA0A4: @ 80CA0A4
-	push {r4,lr}
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080CA0D8 @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r4, r1, r2
-	ldrh r1, [r4, 0xC]
-	cmp r1, 0xF
-	bhi _080CA0E0
-	adds r2, r1, 0x1
-	adds r0, r2, 0x1
-	strh r0, [r4, 0xC]
-	movs r0, 0xF
-	subs r0, r1
-	lsls r0, 1
-	ldr r1, _080CA0DC @ =gUnknown_83F5844
-	adds r0, r1
-	lsls r2, 17
-	lsrs r2, 16
-	movs r1, 0xE0
-	bl LoadPalette
-	b _080CA0F4
-	.align 2, 0
-_080CA0D8: .4byte gTasks
-_080CA0DC: .4byte gUnknown_83F5844
-_080CA0E0:
-	ldr r1, _080CA0FC @ =0x00001010
-	movs r0, 0x52
-	bl SetGpuReg
-	ldr r1, _080CA100 @ =0x00003e41
-	movs r0, 0x50
-	bl SetGpuReg
-	ldr r0, _080CA104 @ =sub_80CA108
-	str r0, [r4]
-_080CA0F4:
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080CA0FC: .4byte 0x00001010
-_080CA100: .4byte 0x00003e41
-_080CA104: .4byte sub_80CA108
-	thumb_func_end sub_80CA0A4
-
-	thumb_func_start sub_80CA108
-sub_80CA108: @ 80CA108
-	push {r4,r5,lr}
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080CA13C @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r5, r1, r2
-	ldrh r0, [r5, 0xA]
-	movs r1, 0x10
-	subs r1, r0
-	lsls r1, 16
-	lsrs r4, r1, 16
-	movs r0, 0x80
-	lsls r0, 21
-	adds r1, r0
-	lsrs r1, 16
-	movs r0, 0x52
-	bl SetGpuReg
-	cmp r4, 0
-	beq _080CA140
-	ldrh r0, [r5, 0xA]
-	adds r0, 0x1
-	strh r0, [r5, 0xA]
-	b _080CA152
-	.align 2, 0
-_080CA13C: .4byte gTasks
-_080CA140:
-	ldr r0, _080CA158 @ =gUnknown_83F5824
-	movs r1, 0
-	movs r2, 0x20
-	bl LoadPalette
-	ldr r0, _080CA15C @ =gMain
-	ldr r0, [r0, 0x8]
-	bl SetMainCallback2
-_080CA152:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080CA158: .4byte gUnknown_83F5824
-_080CA15C: .4byte gMain
-	thumb_func_end sub_80CA108
-
-	thumb_func_start sub_80CA160
-sub_80CA160: @ 80CA160
-	push {r4,lr}
-	adds r4, r0, 0
-	lsls r4, 24
-	lsrs r4, 24
-	ldr r0, _080CA188 @ =sub_80CA190
-	movs r1, 0
-	bl CreateTask
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080CA18C @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r1, r2
-	strh r4, [r1, 0xE]
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080CA188: .4byte sub_80CA190
-_080CA18C: .4byte gTasks
-	thumb_func_end sub_80CA160
-
-	thumb_func_start sub_80CA190
-sub_80CA190: @ 80CA190
-	push {r4-r6,lr}
-	sub sp, 0x4
-	lsls r0, 24
-	lsrs r5, r0, 24
-	lsls r0, r5, 2
-	adds r0, r5
-	lsls r0, 3
-	ldr r1, _080CA1B8 @ =gTasks+0x8
-	adds r4, r0, r1
-	movs r1, 0
-	ldrsh r0, [r4, r1]
-	cmp r0, 0x5
-	bls _080CA1AC
-	b _080CA2D2
-_080CA1AC:
-	lsls r0, 2
-	ldr r1, _080CA1BC @ =_080CA1C0
-	adds r0, r1
-	ldr r0, [r0]
-	mov pc, r0
-	.align 2, 0
-_080CA1B8: .4byte gTasks+0x8
-_080CA1BC: .4byte _080CA1C0
-	.align 2, 0
-_080CA1C0:
-	.4byte _080CA1D8
-	.4byte _080CA208
-	.4byte _080CA224
-	.4byte _080CA24E
-	.4byte _080CA262
-	.4byte _080CA2A4
-_080CA1D8:
-	ldr r0, _080CA204 @ =gMain
-	ldr r2, [r0, 0xC]
-	adds r0, r5, 0
-	movs r1, 0x5
-	bl SetWordTaskArg
-	movs r0, 0
-	bl SetVBlankCallback
-	bl sub_80F8180
-	ldrb r0, [r4, 0x6]
-	bl sub_80F819C
-	movs r0, 0x1
-	negs r0, r0
-	movs r1, 0x10
-	movs r2, 0
-	bl BlendPalettes
-	b _080CA294
-	.align 2, 0
-_080CA204: .4byte gMain
-_080CA208:
-	bl sub_80F8258
-	cmp r0, 0
-	bne _080CA2D2
-	ldrb r0, [r4, 0x6]
-	bl sub_80F8318
-	strh r0, [r4, 0x8]
-	lsls r0, 24
-	lsrs r0, 24
-	movs r1, 0x3
-	bl CopyWindowToVram
-	b _080CA294
-_080CA224:
-	bl IsDma3ManagerBusyWithBgCopy
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0
-	bne _080CA2D2
-	movs r1, 0x1
-	negs r1, r1
-	str r0, [sp]
-	adds r0, r1, 0
-	movs r2, 0x10
-	movs r3, 0
-	bl BeginNormalPaletteFade
-	adds r0, r5, 0
-	movs r1, 0x5
-	bl GetWordTaskArg
-	bl SetVBlankCallback
-	b _080CA294
-_080CA24E:
-	bl UpdatePaletteFade
-	lsls r0, 24
-	cmp r0, 0
-	bne _080CA2D2
-	ldrb r0, [r4, 0x6]
-	bl sub_80F856C
-	strh r0, [r4, 0x4]
-	b _080CA294
-_080CA262:
-	ldrh r0, [r4, 0x2]
-	adds r0, 0x1
-	strh r0, [r4, 0x2]
-	lsls r0, 16
-	asrs r0, 16
-	movs r2, 0x4
-	ldrsh r1, [r4, r2]
-	cmp r0, r1
-	bgt _080CA280
-	ldr r0, _080CA29C @ =gMain
-	ldrh r1, [r0, 0x2C]
-	movs r0, 0x2
-	ands r0, r1
-	cmp r0, 0
-	beq _080CA2D2
-_080CA280:
-	movs r0, 0x1
-	negs r0, r0
-	movs r1, 0x2
-	negs r1, r1
-	ldr r2, _080CA2A0 @ =0x00007fff
-	str r2, [sp]
-	movs r2, 0
-	movs r3, 0x10
-	bl BeginNormalPaletteFade
-_080CA294:
-	ldrh r0, [r4]
-	adds r0, 0x1
-	strh r0, [r4]
-	b _080CA2D2
-	.align 2, 0
-_080CA29C: .4byte gMain
-_080CA2A0: .4byte 0x00007fff
-_080CA2A4:
-	bl UpdatePaletteFade
-	lsls r0, 24
-	cmp r0, 0
-	bne _080CA2D2
-	lsls r6, r5, 2
-	movs r1, 0
-	adds r0, r4, 0
-	adds r0, 0x1E
-_080CA2B6:
-	strh r1, [r0]
-	subs r0, 0x2
-	cmp r0, r4
-	bge _080CA2B6
-	movs r1, 0x8
-	ldrsh r0, [r4, r1]
-	bl sub_80F8234
-	ldr r1, _080CA2DC @ =gTasks
-	adds r0, r6, r5
-	lsls r0, 3
-	adds r0, r1
-	ldr r1, _080CA2E0 @ =sub_80CA004
-	str r1, [r0]
-_080CA2D2:
-	add sp, 0x4
-	pop {r4-r6}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080CA2DC: .4byte gTasks
-_080CA2E0: .4byte sub_80CA004
-	thumb_func_end sub_80CA190
-
-	.align 2, 0 @ Don't pad with nop.
diff --git a/asm/overworld.s b/asm/overworld.s
index 571d305b4..14afde17a 100644
--- a/asm/overworld.s
+++ b/asm/overworld.s
@@ -1739,7 +1739,7 @@ _080558D4:
 	bl DoCurrentWeather
 	bl ResetFieldTasksArgs
 	bl mapheader_run_script_with_tag_x5
-	bl sub_80561B4
+	bl GetLastUsedWarpMapSectionId
 	ldr r1, _0805591C @ =gMapHeader
 	lsls r0, 24
 	lsrs r0, 24
@@ -2899,8 +2899,8 @@ GetCurrentMapType: @ 8056188
 _0805619C: .4byte gSaveBlock1Ptr
 	thumb_func_end GetCurrentMapType
 
-	thumb_func_start get_map_light_from_warp0
-get_map_light_from_warp0: @ 80561A0
+	thumb_func_start GetLastUsedWarpMapType
+GetLastUsedWarpMapType: @ 80561A0
 	push {lr}
 	ldr r0, _080561B0 @ =gUnknown_2031DB4
 	bl get_map_light_level_from_warp
@@ -2910,10 +2910,10 @@ get_map_light_from_warp0: @ 80561A0
 	bx r1
 	.align 2, 0
 _080561B0: .4byte gUnknown_2031DB4
-	thumb_func_end get_map_light_from_warp0
+	thumb_func_end GetLastUsedWarpMapType
 
-	thumb_func_start sub_80561B4
-sub_80561B4: @ 80561B4
+	thumb_func_start GetLastUsedWarpMapSectionId
+GetLastUsedWarpMapSectionId: @ 80561B4
 	push {lr}
 	ldr r1, _080561D4 @ =gUnknown_2031DB4
 	movs r0, 0
@@ -2931,7 +2931,7 @@ sub_80561B4: @ 80561B4
 	bx r1
 	.align 2, 0
 _080561D4: .4byte gUnknown_2031DB4
-	thumb_func_end sub_80561B4
+	thumb_func_end GetLastUsedWarpMapSectionId
 
 	thumb_func_start IsMapTypeOutdoors
 IsMapTypeOutdoors: @ 80561D8
@@ -3579,7 +3579,7 @@ CB2_LoadMap: @ 805671C
 	bl ScriptContext2_Disable
 	movs r0, 0
 	bl SetMainCallback1
-	ldr r0, _08056740 @ =sub_80C9BFC
+	ldr r0, _08056740 @ =CB2_DoChangeMap
 	bl SetMainCallback2
 	ldr r1, _08056744 @ =gMain
 	ldr r0, _08056748 @ =sub_805674C
@@ -3587,7 +3587,7 @@ CB2_LoadMap: @ 805671C
 	pop {r0}
 	bx r0
 	.align 2, 0
-_08056740: .4byte sub_80C9BFC
+_08056740: .4byte CB2_DoChangeMap
 _08056744: .4byte gMain
 _08056748: .4byte sub_805674C
 	thumb_func_end CB2_LoadMap
@@ -4196,7 +4196,7 @@ _08056C72:
 	bl InitTilesetAnimations
 	b _08056CCA
 _08056C78:
-	bl sub_80561B4
+	bl GetLastUsedWarpMapSectionId
 	ldr r5, _08056CA4 @ =gMapHeader
 	lsls r0, 24
 	lsrs r0, 24
@@ -4205,13 +4205,13 @@ _08056C78:
 	beq _08056CA8
 	ldrb r0, [r5, 0x14]
 	movs r1, 0x1
-	bl sub_80F8154
+	bl MapHasPreviewScreen_HandleQLState2
 	cmp r0, 0x1
 	bne _08056CA8
 	ldrb r0, [r5, 0x14]
-	bl sub_80F819C
+	bl MapPreview_LoadGfx
 	ldrb r0, [r5, 0x14]
-	bl sub_80F8268
+	bl MapPreview_StartForestTransition
 	b _08056CCA
 	.align 2, 0
 _08056CA4: .4byte gMapHeader
@@ -4922,7 +4922,7 @@ sub_805726C: @ 805726C
 	bl ScriptContext2_Disable
 	movs r0, 0
 	bl SetMainCallback1
-	ldr r0, _0805729C @ =sub_80C9BFC
+	ldr r0, _0805729C @ =CB2_DoChangeMap
 	bl SetMainCallback2
 	ldr r1, _080572A0 @ =gMain
 	ldr r0, _080572A4 @ =sub_80572D8
@@ -4931,7 +4931,7 @@ sub_805726C: @ 805726C
 	bx r0
 	.align 2, 0
 _08057298: .4byte gUnknown_2036E28
-_0805729C: .4byte sub_80C9BFC
+_0805729C: .4byte CB2_DoChangeMap
 _080572A0: .4byte gMain
 _080572A4: .4byte sub_80572D8
 	thumb_func_end sub_805726C
diff --git a/data/fldeff_flash.s b/data/fldeff_flash.s
deleted file mode 100644
index ddffff5c1..000000000
--- a/data/fldeff_flash.s
+++ /dev/null
@@ -1,74 +0,0 @@
-#include "constants/species.h"
-#include "constants/items.h"
-	.include "asm/macros.inc"
-	.include "constants/constants.inc"
-	.section .rodata
-	.align 2
-
-gUnknown_83F5738:: @ 83F5738
-	.byte 1, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 2, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 3, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 5, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 6, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 7, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 8, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 9, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 4, 1, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 2, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 3, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 5, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 6, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 7, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 8, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 9, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 0, 0, 0, 0
-	.4byte NULL
-	.4byte NULL
-
-gUnknown_83F5804:: @ 83F5804
-	.incbin "graphics/field_effects/flash_white.gbapal"
-
-gUnknown_83F5824:: @ 83F5824
-	.incbin "graphics/field_effects/flash_black.gbapal"
-
-gUnknown_83F5844:: @ 83F5844
-	.incbin "graphics/field_effects/flash_gradient.gbapal"
-
-gUnknown_83F5864:: @ 83F5864
-	.incbin "graphics/field_effects/flash_effect_map.bin.lz"
-
-gUnknown_83F5A44:: @ 83F5A44
-	.incbin "graphics/field_effects/flash_effect_tiles.4bpp.lz"
diff --git a/include/event_scripts.h b/include/event_scripts.h
index 3fda94a5f..c211e3a34 100644
--- a/include/event_scripts.h
+++ b/include/event_scripts.h
@@ -1209,4 +1209,7 @@ extern const u8 CableClub_Text_AwaitingLinkupBCancel[];
 extern const u8 CableClub_Text_StartLinkWithXPlayersAConfirmBCancel[];
 extern const u8 CableClub_Text_PleaseWaitBCancel[];
 
+// fldeff_flash
+extern const u8 EventScript_FldEffFlash[];
+
 #endif //GUARD_EVENT_SCRIPTS_H
diff --git a/include/field_weather.h b/include/field_weather.h
index 115cc0dca..6b62f0edd 100644
--- a/include/field_weather.h
+++ b/include/field_weather.h
@@ -3,7 +3,7 @@
 
 #include "global.h"
 
-void FadeScreen(u8, s8);
+void FadeScreen(u8 mode, s8 delay);
 
 void SetSav1Weather(u32);
 u8 GetSav1Weather(void);
diff --git a/include/fldeff.h b/include/fldeff.h
index 00f2d01f4..9dd6121b2 100644
--- a/include/fldeff.h
+++ b/include/fldeff.h
@@ -13,8 +13,8 @@ bool8 CheckObjectGraphicsInFrontOfPlayer(u8 graphicsId);
 u8 CreateFieldEffectShowMon(void);
 
 // flash
-u8 sub_80C9DCC(u8 lightLevel, u8 mapType);
-u8 sub_80C9D7C(u8 mapType1, u8 mapType2);
+u8 MapTransitionIsExit(u8 lightLevel, u8 mapType);
+u8 MapTransitionIsEnter(u8 mapType1, u8 mapType2);
 bool8 SetUpFieldMove_Flash(void);
 
 // cut
diff --git a/include/map_preview_screen.h b/include/map_preview_screen.h
index ea85baf71..a287c6f89 100644
--- a/include/map_preview_screen.h
+++ b/include/map_preview_screen.h
@@ -34,21 +34,30 @@ enum MapPreviewScreenId
     MPS_COUNT
 };
 
+#define MPS_TYPE_CAVE   0
+#define MPS_TYPE_FOREST 1
+#define MPS_TYPE_ANY    2
+
 struct MapPreviewScreen
 {
     u8 mapsec;
-    bool8 forceFirstTime;
+    u8 type;
     u16 flagId;
     const void * tilesptr;
     const void * tilemapptr;
     const void * palptr;
 };
 
-u16 sub_80F8318(u8 id);
-void sub_80F85BC(u16 a0);
-u16 sub_80F856C(u8 id);
-bool8 sub_80F8110(u8 mapsec, bool8 forceFirstTime);
-bool32 sub_80F83B0(void);
+u16 MapPreview_CreateMapNameWindow(u8 id);
+void MapPreview_SetFlag(u16 a0);
+u16 MapPreview_GetDuration(u8 id);
+bool8 MapHasPreviewScreen(u8 mapsec, u8 type);
+bool32 ForestMapPreviewScreenIsRunning(void);
 const struct MapPreviewScreen * GetDungeonMapPreviewScreenInfo(u8 mapsec);
+bool32 MapHasPreviewScreen_HandleQLState2(u8 mapsec, u8 type);
+void MapPreview_InitBgs(void);
+void MapPreview_LoadGfx(u8 mapsec);
+bool32 MapPreview_IsGfxLoadFinished(void);
+void MapPreview_Unload(s32 windowId);
 
 #endif //GUARD_MAP_PREVIEW_SCREEN_H
diff --git a/include/overworld.h b/include/overworld.h
index daaa5e6e8..02492f74b 100644
--- a/include/overworld.h
+++ b/include/overworld.h
@@ -157,7 +157,7 @@ void Overworld_ResetStateAfterDigEscRope(void);
 bool32 sub_8058244(void);
 u8 GetCurrentMapType(void);
 
-u8 get_map_light_from_warp0(void);
+u8 GetLastUsedWarpMapType(void);
 const struct MapHeader *warp1_get_mapheader(void);
 void TryFadeOutOldMapMusic(void);
 void CB2_ReturnToFieldCableClub(void);
@@ -192,6 +192,7 @@ void sub_8057F48(void);
 void SetMainCallback1(MainCallback cb);
 void CB1_Overworld(void);
 void sub_80568C4(void);
+u8 GetLastUsedWarpMapSectionId(void);
 
 extern u16 gHeldKeyCodeToSend;
 
diff --git a/include/quest_log.h b/include/quest_log.h
index 3241046bc..b2645954f 100644
--- a/include/quest_log.h
+++ b/include/quest_log.h
@@ -26,7 +26,7 @@ extern const u16 gUnknown_84566A8[];
 void sub_8112720(u8);
 void SetQuestLogEvent(u16, const u16 *);
 void sub_811539C(void);
-void sub_8115748(u16);
+void QuestLog_RecordEnteredMap(u16);
 u8 sub_8112CAC(void);
 bool8 QuestLog_SchedulePlaybackCB(void (*func)(void));
 void sub_8111F38(u16 offset, u16 idx);
diff --git a/ld_script.txt b/ld_script.txt
index b919db2ef..c2b35f7a2 100644
--- a/ld_script.txt
+++ b/ld_script.txt
@@ -183,7 +183,7 @@ SECTIONS {
         src/battle_ai_script_commands.o(.text);
         src/fldeff_rocksmash.o(.text);
         src/fldeff_dig.o(.text);
-        asm/fldeff_flash.o(.text);
+        src/fldeff_flash.o(.text);
         src/post_battle_event_funcs.o(.text);
         src/prof_pc.o(.text);
         src/hof_pc.o(.text);
@@ -489,7 +489,7 @@ SECTIONS {
         src/region_map.o(.rodata);
         src/image_processing_effects.o(.rodata);
         src/battle_ai_script_commands.o(.rodata);
-        data/fldeff_flash.o(.rodata);
+        src/fldeff_flash.o(.rodata);
         src/field_specials.o(.rodata);
         src/battle_records.o(.rodata);
         src/evolution_scene.o(.rodata);
diff --git a/src/credits.c b/src/credits.c
index 63d4c9c85..e0d57a2a4 100644
--- a/src/credits.c
+++ b/src/credits.c
@@ -15,6 +15,7 @@
 #include "sound.h"
 #include "constants/species.h"
 #include "constants/maps.h"
+#include "constants/field_weather.h"
 
 #if defined(FIRERED)
 #define TITLE_TEXT gString_PokemonFireRed_Staff
@@ -918,7 +919,7 @@ static s32 RollCredits(void)
             case CREDITSSCRCMD_MON:
                 sCreditsMgr->mainseqno = CREDITSSCENE_MON_DESTROY_ASSETS;
                 sCreditsMgr->whichMon = sCreditsScript[sCreditsMgr->scrcmdidx].param;
-                FadeScreen(1, 0);
+                FadeScreen(FADE_TO_BLACK, 0);
                 break;
             case CREDITSSCRCMD_THEENDGFX:
                 sCreditsMgr->mainseqno = CREDITSSCENE_THEEND_DESTROY_ASSETS;
diff --git a/src/field_fadetransition.c b/src/field_fadetransition.c
index 4ff105056..6c3a37bb4 100644
--- a/src/field_fadetransition.c
+++ b/src/field_fadetransition.c
@@ -23,6 +23,7 @@
 #include "start_menu.h"
 #include "constants/songs.h"
 #include "constants/event_object_movement.h"
+#include "constants/field_weather.h"
 
 static void sub_807DF4C(u8 a0);
 static void sub_807DFBC(u8 taskId);
@@ -52,16 +53,16 @@ void palette_bg_faded_fill_black(void)
 
 void WarpFadeInScreen(void)
 {
-    switch (sub_80C9DCC(get_map_light_from_warp0(), GetCurrentMapType()))
+    switch (MapTransitionIsExit(GetLastUsedWarpMapType(), GetCurrentMapType()))
     {
     case 0:
         palette_bg_faded_fill_black();
-        FadeScreen(0, 0);
+        FadeScreen(FADE_FROM_BLACK, 0);
         palette_bg_faded_fill_black();
         break;
     case 1:
         palette_bg_faded_fill_white();
-        FadeScreen(2, 0);
+        FadeScreen(FADE_FROM_WHITE, 0);
         palette_bg_faded_fill_white();
         break;
     }
@@ -69,16 +70,16 @@ void WarpFadeInScreen(void)
 
 static void sub_807DBAC(void)
 {
-    switch (sub_80C9DCC(get_map_light_from_warp0(), GetCurrentMapType()))
+    switch (MapTransitionIsExit(GetLastUsedWarpMapType(), GetCurrentMapType()))
     {
     case 0:
         palette_bg_faded_fill_black();
-        FadeScreen(0, 3);
+        FadeScreen(FADE_FROM_BLACK, 3);
         palette_bg_faded_fill_black();
         break;
     case 1:
         palette_bg_faded_fill_white();
-        FadeScreen(2, 3);
+        FadeScreen(FADE_FROM_WHITE, 3);
         palette_bg_faded_fill_white();
         break;
     }
@@ -87,24 +88,24 @@ static void sub_807DBAC(void)
 void FadeInFromBlack(void)
 {
     palette_bg_faded_fill_black();
-    FadeScreen(0, 0);
+    FadeScreen(FADE_FROM_BLACK, 0);
     palette_bg_faded_fill_black();
 }
 
 void WarpFadeOutScreen(void)
 {
     const struct MapHeader *header = warp1_get_mapheader();
-    if (header->regionMapSectionId != gMapHeader.regionMapSectionId && sub_80F8110(header->regionMapSectionId, FALSE))
-        FadeScreen(1, 0);
+    if (header->regionMapSectionId != gMapHeader.regionMapSectionId && MapHasPreviewScreen(header->regionMapSectionId, MPS_TYPE_CAVE))
+        FadeScreen(FADE_TO_BLACK, 0);
     else
     {
-        switch (sub_80C9D7C(GetCurrentMapType(), header->mapType))
+        switch (MapTransitionIsEnter(GetCurrentMapType(), header->mapType))
         {
-        case 0:
-            FadeScreen(1, 0);
+        case FALSE:
+            FadeScreen(FADE_TO_BLACK, 0);
             break;
-        case 1:
-            FadeScreen(3, 0);
+        case TRUE:
+            FadeScreen(FADE_TO_WHITE, 0);
             break;
         }
     }
@@ -112,13 +113,13 @@ void WarpFadeOutScreen(void)
 
 static void sub_807DC70(void)
 {
-    switch (sub_80C9D7C(GetCurrentMapType(), warp1_get_mapheader()->mapType))
+    switch (MapTransitionIsEnter(GetCurrentMapType(), warp1_get_mapheader()->mapType))
     {
-    case 0:
-        FadeScreen(1, 3);
+    case FALSE:
+        FadeScreen(FADE_TO_BLACK, 3);
         break;
-    case 1:
-        FadeScreen(3, 3);
+    case TRUE:
+        FadeScreen(FADE_TO_WHITE, 3);
         break;
     }
 }
@@ -246,7 +247,7 @@ static void sub_807DE78(bool8 a0)
     if (MetatileBehavior_IsWarpDoor_2(behavior) == TRUE)
     {
         func = sub_807DFBC;
-        switch (sub_80C9DCC(get_map_light_from_warp0(), GetCurrentMapType()))
+        switch (MapTransitionIsExit(GetLastUsedWarpMapType(), GetCurrentMapType()))
         {
         case 0:
             palette_bg_faded_fill_black();
@@ -521,7 +522,7 @@ static bool32 sub_807E40C(void)
 
 bool32 sub_807E418(void)
 {
-    if (IsWeatherNotFadingIn() == TRUE && sub_80F83B0())
+    if (IsWeatherNotFadingIn() == TRUE && ForestMapPreviewScreenIsRunning())
         return TRUE;
     else
         return FALSE;
@@ -654,7 +655,7 @@ static void sub_807E678(u8 taskId)
     {
     case 0:
         ClearLinkCallback_2();
-        FadeScreen(1, 0);
+        FadeScreen(FADE_TO_BLACK, 0);
         TryFadeOutOldMapMusic();
         PlaySE(SE_KAIDAN);
         data[0]++;
diff --git a/src/fldeff_flash.c b/src/fldeff_flash.c
new file mode 100644
index 000000000..58cb4c251
--- /dev/null
+++ b/src/fldeff_flash.c
@@ -0,0 +1,479 @@
+#include "global.h"
+#include "gflib.h"
+#include "event_data.h"
+#include "event_scripts.h"
+#include "fldeff.h"
+#include "field_effect.h"
+#include "map_preview_screen.h"
+#include "overworld.h"
+#include "party_menu.h"
+#include "script.h"
+#include "constants/songs.h"
+#include "constants/map_types.h"
+
+struct FlashStruct
+{
+    u8 fromType;
+    u8 toType;
+    bool8 isEnter;
+    bool8 isExit;
+    void (*func1)(void);
+    void (*func2)(u8 mapSecId);
+};
+
+static void FieldCallback_Flash(void);
+static void FldEff_UseFlash(void);
+static bool8 TryDoMapTransition(void);
+static void FlashTransition_Exit(void);
+static void Task_FlashTransition_Exit_0(u8 taskId);
+static void Task_FlashTransition_Exit_1(u8 taskId);
+static void Task_FlashTransition_Exit_2(u8 taskId);
+static void Task_FlashTransition_Exit_3(u8 taskId);
+static void Task_FlashTransition_Exit_4(u8 taskId);
+static void FlashTransition_Enter(void);
+static void Task_FlashTransition_Enter_0(u8 taskId);
+static void Task_FlashTransition_Enter_1(u8 taskId);
+static void Task_FlashTransition_Enter_2(u8 taskId);
+static void Task_FlashTransition_Enter_3(u8 taskId);
+static void RunMapPreviewScreen(u8 mapsecId);
+static void Task_MapPreviewScreen_0(u8 taskId);
+
+static const struct FlashStruct sTransitionTypes[] = {
+    {
+        .fromType = MAP_TYPE_TOWN,
+        .toType = MAP_TYPE_UNDERGROUND,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = FlashTransition_Enter,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_CITY,
+        .toType = MAP_TYPE_UNDERGROUND,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = FlashTransition_Enter,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_ROUTE,
+        .toType = MAP_TYPE_UNDERGROUND,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = FlashTransition_Enter,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_UNDERWATER,
+        .toType = MAP_TYPE_UNDERGROUND,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = FlashTransition_Enter,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_OCEAN_ROUTE,
+        .toType = MAP_TYPE_UNDERGROUND,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = FlashTransition_Enter,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_UNKNOWN,
+        .toType = MAP_TYPE_UNDERGROUND,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = FlashTransition_Enter,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_INDOOR,
+        .toType = MAP_TYPE_UNDERGROUND,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = FlashTransition_Enter,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_SECRET_BASE,
+        .toType = MAP_TYPE_UNDERGROUND,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = FlashTransition_Enter,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_UNDERGROUND,
+        .toType = MAP_TYPE_TOWN,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = FlashTransition_Exit,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_UNDERGROUND,
+        .toType = MAP_TYPE_CITY,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = FlashTransition_Exit,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_UNDERGROUND,
+        .toType = MAP_TYPE_ROUTE,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = FlashTransition_Exit,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_UNDERGROUND,
+        .toType = MAP_TYPE_UNDERWATER,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = FlashTransition_Exit,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_UNDERGROUND,
+        .toType = MAP_TYPE_OCEAN_ROUTE,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = FlashTransition_Exit,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_UNDERGROUND,
+        .toType = MAP_TYPE_UNKNOWN,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = FlashTransition_Exit,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_UNDERGROUND,
+        .toType = MAP_TYPE_INDOOR,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = FlashTransition_Exit,
+        .func2 = RunMapPreviewScreen
+    }, {
+        .fromType = MAP_TYPE_UNDERGROUND,
+        .toType = MAP_TYPE_SECRET_BASE,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = FlashTransition_Exit,
+        .func2 = RunMapPreviewScreen
+    }, {0}
+};
+
+static const u16 sCaveTransitionPalette_White[] = INCBIN_U16("graphics/field_effects/flash_white.gbapal");
+static const u16 sCaveTransitionPalette_Black[] = INCBIN_U16("graphics/field_effects/flash_black.gbapal");
+static const u16 sCaveTransitionPalette_Gradient[] = INCBIN_U16("graphics/field_effects/flash_gradient.gbapal");
+static const u32 sCaveTransitionTilemap[] = INCBIN_U32("graphics/field_effects/flash_effect_map.bin.lz");
+static const u32 sCaveTransitionTiles[] = INCBIN_U32("graphics/field_effects/flash_effect_tiles.4bpp.lz");
+
+bool8 SetUpFieldMove_Flash(void)
+{
+    if (gMapHeader.cave != TRUE)
+        return FALSE;
+
+    if (FlagGet(FLAG_SYS_FLASH_ACTIVE))
+        return FALSE;
+
+    gFieldCallback2 = FieldCallback_PrepareFadeInFromMenu;
+    gPostMenuFieldCallback = FieldCallback_Flash;
+    return TRUE;
+}
+
+static void FieldCallback_Flash(void)
+{
+    u8 taskId = CreateFieldEffectShowMon();
+    gFieldEffectArguments[0] = GetCursorSelectionMonId();
+    gTasks[taskId].data[8] = ((uintptr_t)FldEff_UseFlash) >> 16;
+    gTasks[taskId].data[9] = ((uintptr_t)FldEff_UseFlash);
+}
+
+static void FldEff_UseFlash(void)
+{
+    PlaySE(SE_W115);
+    FlagSet(FLAG_SYS_FLASH_ACTIVE);
+    ScriptContext1_SetupScript(EventScript_FldEffFlash);
+}
+
+// Map transition animatics
+
+static void CB2_ChangeMapMain(void)
+{
+    RunTasks();
+    AnimateSprites();
+    BuildOamBuffer();
+    UpdatePaletteFade();
+}
+
+static void VBC_ChangeMapVBlank(void)
+{
+    LoadOam();
+    ProcessSpriteCopyRequests();
+    TransferPlttBuffer();
+}
+
+void CB2_DoChangeMap(void)
+{
+    SetVBlankCallback(NULL);
+
+    SetGpuReg(REG_OFFSET_DISPCNT, 0);
+    SetGpuReg(REG_OFFSET_BG2CNT, 0);
+    SetGpuReg(REG_OFFSET_BG1CNT, 0);
+    SetGpuReg(REG_OFFSET_BG0CNT, 0);
+    SetGpuReg(REG_OFFSET_BG2HOFS, 0);
+    SetGpuReg(REG_OFFSET_BG2VOFS, 0);
+    SetGpuReg(REG_OFFSET_BG1HOFS, 0);
+    SetGpuReg(REG_OFFSET_BG1VOFS, 0);
+    SetGpuReg(REG_OFFSET_BG0HOFS, 0);
+    SetGpuReg(REG_OFFSET_BG0VOFS, 0);
+
+    DmaFill16(3, 0, (void *)VRAM, VRAM_SIZE);
+    DmaFill32(3, 0, (void *)OAM, OAM_SIZE);
+    DmaFill16(3, 0, (void *)(PLTT + 2), PLTT_SIZE - 2);
+    ResetPaletteFade();
+    ResetTasks();
+    ResetSpriteData();
+    EnableInterrupts(INTR_FLAG_VBLANK);
+    SetVBlankCallback(VBC_ChangeMapVBlank);
+    SetMainCallback2(CB2_ChangeMapMain);
+    if (!TryDoMapTransition())
+        SetMainCallback2(gMain.savedCallback);
+}
+
+static bool8 TryDoMapTransition(void)
+{
+    u8 fromType = GetLastUsedWarpMapType();
+    u8 toType = GetCurrentMapType();
+    u8 i = 0;
+    if (GetLastUsedWarpMapSectionId() != gMapHeader.regionMapSectionId && MapHasPreviewScreen_HandleQLState2(gMapHeader.regionMapSectionId, MPS_TYPE_CAVE) == TRUE)
+    {
+        RunMapPreviewScreen(gMapHeader.regionMapSectionId);
+        return TRUE;
+    }
+    for (; sTransitionTypes[i].fromType != 0; i++)
+    {
+        if (sTransitionTypes[i].fromType == fromType && sTransitionTypes[i].toType == toType)
+        {
+            sTransitionTypes[i].func1();
+            return TRUE;
+        }
+    }
+    return FALSE;
+}
+
+bool8 MapTransitionIsEnter(u8 _fromType, u8 _toType)
+{
+    u8 fromType = _fromType;
+    u8 toType = _toType;
+    u8 i = 0;
+    for (; sTransitionTypes[i].fromType != 0; i++)
+    {
+        if (sTransitionTypes[i].fromType == fromType && sTransitionTypes[i].toType == toType)
+        {
+            return sTransitionTypes[i].isEnter;
+        }
+    }
+    return FALSE;
+}
+
+bool8 MapTransitionIsExit(u8 _fromType, u8 _toType)
+{
+    u8 fromType = _fromType;
+    u8 toType = _toType;
+    u8 i = 0;
+    for (; sTransitionTypes[i].fromType != 0; i++)
+    {
+        if (sTransitionTypes[i].fromType == fromType && sTransitionTypes[i].toType == toType)
+        {
+            return sTransitionTypes[i].isExit;
+        }
+    }
+    return FALSE;
+}
+
+static void FlashTransition_Exit(void)
+{
+    CreateTask(Task_FlashTransition_Exit_0, 0);
+}
+
+static void Task_FlashTransition_Exit_0(u8 taskId)
+{
+    gTasks[taskId].func = Task_FlashTransition_Exit_1;
+}
+
+static void Task_FlashTransition_Exit_1(u8 taskId)
+{
+    SetGpuReg(REG_OFFSET_DISPCNT, 0);
+    LZ77UnCompVram(sCaveTransitionTiles, (void *)BG_CHAR_ADDR(3));
+    LZ77UnCompVram(sCaveTransitionTilemap, (void *)BG_SCREEN_ADDR(31));
+    LoadPalette(sCaveTransitionPalette_White, 0xE0, 0x20);
+    LoadPalette(sCaveTransitionPalette_Gradient + 8, 0xE0, 0x10);
+    SetGpuReg(REG_OFFSET_BLDCNT, BLDCNT_TGT1_BG0 | BLDCNT_EFFECT_BLEND | BLDCNT_TGT2_BG1 | BLDCNT_TGT2_BG2 | BLDCNT_TGT2_BG3 | BLDCNT_TGT2_OBJ | BLDCNT_TGT2_BD);
+    SetGpuReg(REG_OFFSET_BLDALPHA, 0);
+    SetGpuReg(REG_OFFSET_BLDY, 0);
+    SetGpuReg(REG_OFFSET_BG0CNT, BGCNT_PRIORITY(0) | BGCNT_CHARBASE(3) | BGCNT_SCREENBASE(31));
+    SetGpuReg(REG_OFFSET_DISPCNT, DISPCNT_MODE_0 | DISPCNT_OBJ_1D_MAP | DISPCNT_BG0_ON | DISPCNT_OBJ_ON);
+    gTasks[taskId].func = Task_FlashTransition_Exit_2;
+    gTasks[taskId].data[0] = 16;
+    gTasks[taskId].data[1] = 0;
+}
+
+static void Task_FlashTransition_Exit_2(u8 taskId)
+{
+    u16 r4 = gTasks[taskId].data[1];
+    SetGpuReg(REG_OFFSET_BLDALPHA, (16 << 8) + r4);
+    if (r4 <= 16)
+    {
+        gTasks[taskId].data[1]++;
+    }
+    else
+    {
+        gTasks[taskId].data[2] = 0;
+        gTasks[taskId].func = Task_FlashTransition_Exit_3;
+    }
+}
+
+static void Task_FlashTransition_Exit_3(u8 taskId)
+{
+    u16 r4;
+    SetGpuReg(REG_OFFSET_BLDALPHA, (16 << 8) + 16);
+    r4 = gTasks[taskId].data[2];
+    if (r4 < 8)
+    {
+        gTasks[taskId].data[2]++;
+        LoadPalette(sCaveTransitionPalette_Gradient + 8 + r4, 0xE0, 0x10 - 2 * r4);
+    }
+    else
+    {
+        LoadPalette(sCaveTransitionPalette_White, 0x00, 0x20);
+        gTasks[taskId].func = Task_FlashTransition_Exit_4;
+        gTasks[taskId].data[2] = 8;
+    }
+}
+
+static void Task_FlashTransition_Exit_4(u8 taskId)
+{
+    if (gTasks[taskId].data[2] != 0)
+        gTasks[taskId].data[2]--;
+    else
+        SetMainCallback2(gMain.savedCallback);
+}
+
+static void FlashTransition_Enter(void)
+{
+    CreateTask(Task_FlashTransition_Enter_0, 0);
+}
+
+static void Task_FlashTransition_Enter_0(u8 taskId)
+{
+    gTasks[taskId].func = Task_FlashTransition_Enter_1;
+}
+
+static void Task_FlashTransition_Enter_1(u8 taskId)
+{
+    SetGpuReg(REG_OFFSET_DISPCNT, 0);
+    LZ77UnCompVram(sCaveTransitionTiles, (void *)BG_CHAR_ADDR(3));
+    LZ77UnCompVram(sCaveTransitionTilemap, (void *)BG_SCREEN_ADDR(31));
+    SetGpuReg(REG_OFFSET_BLDCNT, 0);
+    SetGpuReg(REG_OFFSET_BLDALPHA, 0);
+    SetGpuReg(REG_OFFSET_BLDY, 0);
+    SetGpuReg(REG_OFFSET_BG0CNT, BGCNT_PRIORITY(0) | BGCNT_CHARBASE(3) | BGCNT_SCREENBASE(31));
+    SetGpuReg(REG_OFFSET_DISPCNT, DISPCNT_MODE_0 | DISPCNT_OBJ_1D_MAP | DISPCNT_BG0_ON | DISPCNT_OBJ_ON);
+    LoadPalette(sCaveTransitionPalette_White, 0xE0, 0x20);
+    LoadPalette(sCaveTransitionPalette_Black, 0, 0x20);
+    gTasks[taskId].func = Task_FlashTransition_Enter_2;
+    gTasks[taskId].data[0] = 16;
+    gTasks[taskId].data[1] = 0;
+    gTasks[taskId].data[2] = 0;
+}
+
+static void Task_FlashTransition_Enter_2(u8 taskId)
+{
+    u16 r4;
+    r4 = gTasks[taskId].data[2];
+    if (r4 < 16)
+    {
+        gTasks[taskId].data[2]++;
+        gTasks[taskId].data[2]++;
+        LoadPalette(&sCaveTransitionPalette_Gradient[16 - (r4 + 1)], 0xE0, 2 * (r4 + 1));
+    }
+    else
+    {
+        SetGpuReg(REG_OFFSET_BLDALPHA, (16 << 8) + 16);
+        SetGpuReg(REG_OFFSET_BLDCNT, BLDCNT_TGT1_BG0 | BLDCNT_EFFECT_BLEND | BLDCNT_TGT2_BG1 | BLDCNT_TGT2_BG2 | BLDCNT_TGT2_BG3 | BLDCNT_TGT2_OBJ | BLDCNT_TGT2_BD);
+        gTasks[taskId].func = Task_FlashTransition_Enter_3;
+    }
+}
+
+static void Task_FlashTransition_Enter_3(u8 taskId)
+{
+    u16 r4 = 16 - gTasks[taskId].data[1];
+    SetGpuReg(REG_OFFSET_BLDALPHA, (16 << 8) + r4);
+    if (r4 != 0)
+    {
+        gTasks[taskId].data[1]++;
+    }
+    else
+    {
+        LoadPalette(sCaveTransitionPalette_Black, 0x00, 0x20);
+        SetMainCallback2(gMain.savedCallback);
+    }
+}
+
+static void RunMapPreviewScreen(u8 mapSecId)
+{
+    u8 taskId = CreateTask(Task_MapPreviewScreen_0, 0);
+    gTasks[taskId].data[3] = mapSecId;
+}
+
+static void Task_MapPreviewScreen_0(u8 taskId)
+{
+    s16 *data = gTasks[taskId].data;
+    switch (data[0])
+    {
+    case 0:
+        SetWordTaskArg(taskId, 5, (uintptr_t)gMain.vblankCallback);
+        SetVBlankCallback(NULL);
+        MapPreview_InitBgs();
+        MapPreview_LoadGfx(data[3]);
+        BlendPalettes(0xFFFFFFFF, 0x10, RGB_BLACK);
+        data[0]++;
+        break;
+    case 1:
+        if (!MapPreview_IsGfxLoadFinished())
+        {
+            data[4] = MapPreview_CreateMapNameWindow(data[3]);
+            CopyWindowToVram(data[4], 3);
+            data[0]++;
+        }
+        break;
+    case 2:
+        if (!IsDma3ManagerBusyWithBgCopy())
+        {
+            BeginNormalPaletteFade(0xFFFFFFFF, -1, 16, 0, RGB_BLACK);
+            SetVBlankCallback((IntrCallback)GetWordTaskArg(taskId, 5));
+            data[0]++;
+        }
+        break;
+    case 3:
+        if (!UpdatePaletteFade())
+        {
+            data[2] = MapPreview_GetDuration(data[3]);
+            data[0]++;
+        }
+        break;
+    case 4:
+        data[1]++;
+        if (data[1] > data[2] || JOY_HELD(B_BUTTON))
+        {
+            BeginNormalPaletteFade(0xFFFFFFFF, -2, 0, 16, RGB_WHITE);
+            data[0]++;
+        }
+        break;
+    case 5:
+        if (!UpdatePaletteFade())
+        {
+            int i;
+            for (i = 0; i < 16; i++)
+            {
+                data[i] = 0;
+            }
+            MapPreview_Unload(data[4]);
+            gTasks[taskId].func = Task_FlashTransition_Enter_1;
+        }
+        break;
+    }
+}
diff --git a/src/item_use.c b/src/item_use.c
index ec8155eb1..6f81ee0e3 100644
--- a/src/item_use.c
+++ b/src/item_use.c
@@ -41,6 +41,7 @@
 #include "constants/maps.h"
 #include "constants/moves.h"
 #include "constants/songs.h"
+#include "constants/field_weather.h"
 
 static EWRAM_DATA void (*sItemUseOnFieldCB)(u8 taskId) = NULL;
 
@@ -456,7 +457,7 @@ void FieldUseFunc_TmCase(u8 taskId)
     else
     {
         StopPokemonLeagueLightingEffectTask();
-        FadeScreen(1, 0);
+        FadeScreen(FADE_TO_BLACK, 0);
         gTasks[taskId].func = Task_InitTMCaseFromField;
     }
 }
@@ -487,7 +488,7 @@ void FieldUseFunc_BerryPouch(u8 taskId)
     else
     {
         StopPokemonLeagueLightingEffectTask();
-        FadeScreen(1, 0);
+        FadeScreen(FADE_TO_BLACK, 0);
         gTasks[taskId].func = Task_InitBerryPouchFromField;
     }
 }
@@ -530,7 +531,7 @@ void FieldUseFunc_TeachyTv(u8 taskId)
     else
     {
         StopPokemonLeagueLightingEffectTask();
-        FadeScreen(1, 0);
+        FadeScreen(FADE_TO_BLACK, 0);
         gTasks[taskId].func = Task_InitTeachyTvFromField;
     }
 }
@@ -660,7 +661,7 @@ void FieldUseFunc_TownMap(u8 taskId)
     else
     {
         StopPokemonLeagueLightingEffectTask();
-        FadeScreen(1, 0);
+        FadeScreen(FADE_TO_BLACK, 0);
         gTasks[taskId].func = sub_80A1CC0;
     }
 }
@@ -692,7 +693,7 @@ void FieldUseFunc_FameChecker(u8 taskId)
     else
     {
         StopPokemonLeagueLightingEffectTask();
-        FadeScreen(1, 0);
+        FadeScreen(FADE_TO_BLACK, 0);
         gTasks[taskId].func = sub_80A1D68;
     }
 }
diff --git a/src/map_preview_screen.c b/src/map_preview_screen.c
index b5c68acf9..cae25b986 100644
--- a/src/map_preview_screen.c
+++ b/src/map_preview_screen.c
@@ -16,10 +16,10 @@
 #include "map_preview_screen.h"
 #include "constants/region_map.h"
 
-static EWRAM_DATA bool8 gUnknown_203ABEC = FALSE;
-static EWRAM_DATA bool8 gUnknown_203ABED = FALSE;
+static EWRAM_DATA bool8 sHasVisitedMapBefore = FALSE;
+static EWRAM_DATA bool8 sAllocedBg0TilemapBuffer = FALSE;
 
-static void sub_80F83D0(u8 taskId);
+static void Task_RunMapPreviewScreenForest(u8 taskId);
 
 static const u8 gViridianForestMapPreviewPalette[] = INCBIN_U8("data/map_preview/viridian_forest_pal.gbapal");
 static const u8 gViridianForestMapPreviewTiles[] = INCBIN_U8("data/map_preview/viridian_forest_tiles.4bpp.lz");
@@ -88,7 +88,7 @@ static const u8 gAlteringCaveMapPreviewTilemap[] = INCBIN_U8("data/map_preview/a
 static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     [MPS_VIRIDIAN_FOREST] = {
         .mapsec = MAPSEC_VIRIDIAN_FOREST,
-        .forceFirstTime = TRUE,
+        .type = MPS_TYPE_FOREST,
         .flagId = FLAG_WORLD_MAP_VIRIDIAN_FOREST,
         .tilesptr = gViridianForestMapPreviewTiles,
         .tilemapptr = gViridianForestMapPreviewTilemap,
@@ -96,7 +96,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_MT_MOON] = {
         .mapsec = MAPSEC_MT_MOON,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_MT_MOON_1F,
         .tilesptr = gMtMoonMapPreviewTiles,
         .tilemapptr = gMtMoonMapPreviewTilemap,
@@ -104,7 +104,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_DIGLETTS_CAVE] = {
         .mapsec = MAPSEC_DIGLETTS_CAVE,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_DIGLETTS_CAVE_B1F,
         .tilesptr = gDiglettsCaveMapPreviewTiles,
         .tilemapptr = gDiglettsCaveMapPreviewTilemap,
@@ -112,7 +112,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_ROCK_TUNNEL] = {
         .mapsec = MAPSEC_ROCK_TUNNEL,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_ROCK_TUNNEL_1F,
         .tilesptr = gRockTunnelMapPreviewTiles,
         .tilemapptr = gRockTunnelMapPreviewTilemap,
@@ -120,7 +120,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_POKEMON_TOWER] = {
         .mapsec = MAPSEC_POKEMON_TOWER,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_POKEMON_TOWER_1F,
         .tilesptr = gPokemonTowerMapPreviewTiles,
         .tilemapptr = gPokemonTowerMapPreviewTilemap,
@@ -128,7 +128,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_SAFARI_ZONE] = {
         .mapsec = MAPSEC_KANTO_SAFARI_ZONE,
-        .forceFirstTime = TRUE,
+        .type = MPS_TYPE_FOREST,
         .flagId = FLAG_WORLD_MAP_SAFARI_ZONE_CENTER,
         .tilesptr = gKantoSafariZoneMapPreviewTiles,
         .tilemapptr = gKantoSafariZoneMapPreviewTilemap,
@@ -136,7 +136,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_SEAFOAM_ISLANDS] = {
         .mapsec = MAPSEC_SEAFOAM_ISLANDS,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_SEAFOAM_ISLANDS_1F,
         .tilesptr = gSeafoamIslandsMapPreviewTiles,
         .tilemapptr = gSeafoamIslandsMapPreviewTilemap,
@@ -144,7 +144,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_POKEMON_MANSION] = {
         .mapsec = MAPSEC_POKEMON_MANSION,
-        .forceFirstTime = TRUE,
+        .type = MPS_TYPE_FOREST,
         .flagId = FLAG_WORLD_MAP_POKEMON_MANSION_1F,
         .tilesptr = gPokemonMansionMapPreviewTiles,
         .tilemapptr = gPokemonMansionMapPreviewTilemap,
@@ -152,7 +152,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_ROCKET_HIDEOUT] = {
         .mapsec = MAPSEC_ROCKET_HIDEOUT,
-        .forceFirstTime = TRUE,
+        .type = MPS_TYPE_FOREST,
         .flagId = FLAG_WORLD_MAP_ROCKET_HIDEOUT_B1F,
         .tilesptr = gRocketHideoutMapPreviewTiles,
         .tilemapptr = gRocketHideoutMapPreviewTilemap,
@@ -160,7 +160,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_SILPH_CO] = {
         .mapsec = MAPSEC_SILPH_CO,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_SILPH_CO_1F,
         .tilesptr = gSilphCoMapPreviewTiles,
         .tilemapptr = gSilphCoMapPreviewTilemap,
@@ -168,7 +168,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_VICTORY_ROAD] = {
         .mapsec = MAPSEC_KANTO_VICTORY_ROAD,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_VICTORY_ROAD_1F,
         .tilesptr = gKantoVictoryRoadMapPreviewTiles,
         .tilemapptr = gKantoVictoryRoadMapPreviewTilemap,
@@ -176,7 +176,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_CERULEAN_CAVE] = {
         .mapsec = MAPSEC_CERULEAN_CAVE,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_CERULEAN_CAVE_1F,
         .tilesptr = gCeruleanCaveMapPreviewTiles,
         .tilemapptr = gCeruleanCaveMapPreviewTilemap,
@@ -184,7 +184,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_POWER_PLANT] = {
         .mapsec = MAPSEC_POWER_PLANT,
-        .forceFirstTime = TRUE,
+        .type = MPS_TYPE_FOREST,
         .flagId = FLAG_WORLD_MAP_POWER_PLANT,
         .tilesptr = gPowerPlantMapPreviewTiles,
         .tilemapptr = gPowerPlantMapPreviewTilemap,
@@ -192,7 +192,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_MT_EMBER] = {
         .mapsec = MAPSEC_MT_EMBER,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_MT_EMBER_EXTERIOR,
         .tilesptr = gMtEmberMapPreviewTiles,
         .tilemapptr = gMtEmberMapPreviewTilemap,
@@ -200,7 +200,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_ROCKET_WAREHOUSE] = {
         .mapsec = MAPSEC_ROCKET_WAREHOUSE,
-        .forceFirstTime = TRUE,
+        .type = MPS_TYPE_FOREST,
         .flagId = FLAG_WORLD_MAP_THREE_ISLAND_BERRY_FOREST,
         .tilesptr = gRocketWarehouseMapPreviewTiles,
         .tilemapptr = gRocketWarehouseMapPreviewTilemap,
@@ -208,7 +208,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_MONEAN_CHAMBER] = {
         .mapsec = MAPSEC_MONEAN_CHAMBER,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_SEVEN_ISLAND_TANOBY_RUINS_MONEAN_CHAMBER,
         .tilesptr = gMoneanChamberMapPreviewTiles,
         .tilemapptr = gMoneanChamberMapPreviewTilemap,
@@ -216,7 +216,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_DOTTED_HOLE] = {
         .mapsec = MAPSEC_DOTTED_HOLE,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_SIX_ISLAND_DOTTED_HOLE_1F,
         .tilesptr = gDottedHoleMapPreviewTiles,
         .tilemapptr = gDottedHoleMapPreviewTilemap,
@@ -224,7 +224,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_BERRY_FOREST] = {
         .mapsec = MAPSEC_BERRY_FOREST,
-        .forceFirstTime = TRUE,
+        .type = MPS_TYPE_FOREST,
         .flagId = FLAG_WORLD_MAP_THREE_ISLAND_BERRY_FOREST,
         .tilesptr = gBerryForestMapPreviewTiles,
         .tilemapptr = gBerryForestMapPreviewTilemap,
@@ -232,7 +232,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_ICEFALL_CAVE] = {
         .mapsec = MAPSEC_ICEFALL_CAVE,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_FOUR_ISLAND_ICEFALL_CAVE_ENTRANCE,
         .tilesptr = gIcefallCaveMapPreviewTiles,
         .tilemapptr = gIcefallCaveMapPreviewTilemap,
@@ -240,7 +240,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_LOST_CAVE] = {
         .mapsec = MAPSEC_LOST_CAVE,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_FIVE_ISLAND_LOST_CAVE_ENTRANCE,
         .tilesptr = gLostCaveMapPreviewTiles,
         .tilemapptr = gLostCaveMapPreviewTilemap,
@@ -248,7 +248,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_ALTERING_CAVE] = {
         .mapsec = MAPSEC_ALTERING_CAVE,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_SIX_ISLAND_ALTERING_CAVE,
         .tilesptr = gAlteringCaveMapPreviewTiles,
         .tilemapptr = gAlteringCaveMapPreviewTilemap,
@@ -256,7 +256,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_PATTERN_BUSH] = {
         .mapsec = MAPSEC_PATTERN_BUSH,
-        .forceFirstTime = TRUE,
+        .type = MPS_TYPE_FOREST,
         .flagId = FLAG_WORLD_MAP_SIX_ISLAND_PATTERN_BUSH,
         .tilesptr = gViridianForestMapPreviewTiles,
         .tilemapptr = gViridianForestMapPreviewTilemap,
@@ -264,7 +264,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_LIPTOO_CHAMBER] = {
         .mapsec = MAPSEC_LIPTOO_CHAMBER,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_SEVEN_ISLAND_TANOBY_RUINS_MONEAN_CHAMBER,
         .tilesptr = gMoneanChamberMapPreviewTiles,
         .tilemapptr = gMoneanChamberMapPreviewTilemap,
@@ -272,7 +272,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_WEEPTH_CHAMBER] = {
         .mapsec = MAPSEC_WEEPTH_CHAMBER,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_SEVEN_ISLAND_TANOBY_RUINS_MONEAN_CHAMBER,
         .tilesptr = gMoneanChamberMapPreviewTiles,
         .tilemapptr = gMoneanChamberMapPreviewTilemap,
@@ -280,7 +280,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_TDILFORD_CHAMBER] = {
         .mapsec = MAPSEC_DILFORD_CHAMBER,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_SEVEN_ISLAND_TANOBY_RUINS_MONEAN_CHAMBER,
         .tilesptr = gMoneanChamberMapPreviewTiles,
         .tilemapptr = gMoneanChamberMapPreviewTilemap,
@@ -288,7 +288,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_SCUFIB_CHAMBER] = {
         .mapsec = MAPSEC_SCUFIB_CHAMBER,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_SEVEN_ISLAND_TANOBY_RUINS_MONEAN_CHAMBER,
         .tilesptr = gMoneanChamberMapPreviewTiles,
         .tilemapptr = gMoneanChamberMapPreviewTilemap,
@@ -296,7 +296,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_RIXY_CHAMBER] = {
         .mapsec = MAPSEC_RIXY_CHAMBER,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_SEVEN_ISLAND_TANOBY_RUINS_MONEAN_CHAMBER,
         .tilesptr = gMoneanChamberMapPreviewTiles,
         .tilemapptr = gMoneanChamberMapPreviewTilemap,
@@ -304,7 +304,7 @@ static const struct MapPreviewScreen sMapPreviewScreenData[MPS_COUNT] = {
     },
     [MPS_VIAPOIS_CHAMBER] = {
         .mapsec = MAPSEC_VIAPOIS_CHAMBER,
-        .forceFirstTime = FALSE,
+        .type = MPS_TYPE_CAVE,
         .flagId = FLAG_WORLD_MAP_SEVEN_ISLAND_TANOBY_RUINS_MONEAN_CHAMBER,
         .tilesptr = gMoneanChamberMapPreviewTiles,
         .tilemapptr = gMoneanChamberMapPreviewTilemap,
@@ -328,7 +328,7 @@ static const struct BgTemplate sMapPreviewBgTemplate[1] = {
     }
 };
 
-static u8 sub_80F80E4(u8 mapsec)
+static u8 GetMapPreviewScreenIdx(u8 mapsec)
 {
     s32 i;
 
@@ -342,20 +342,20 @@ static u8 sub_80F80E4(u8 mapsec)
     return MPS_COUNT;
 }
 
-bool8 sub_80F8110(u8 mapsec, u8 forceFirstTime)
+bool8 MapHasPreviewScreen(u8 mapsec, u8 type)
 {
     u8 idx;
 
-    idx = sub_80F80E4(mapsec);
+    idx = GetMapPreviewScreenIdx(mapsec);
     if (idx != MPS_COUNT)
     {
-        if (forceFirstTime == 2)
+        if (type == MPS_TYPE_ANY)
         {
             return TRUE;
         }
         else
         {
-            return sMapPreviewScreenData[idx].forceFirstTime == forceFirstTime ? TRUE : FALSE;
+            return sMapPreviewScreenData[idx].type == type ? TRUE : FALSE;
         }
     }
     else
@@ -364,29 +364,29 @@ bool8 sub_80F8110(u8 mapsec, u8 forceFirstTime)
     }
 }
 
-bool8 sub_80F8154(u8 mapsec, u8 forceFirstTime)
+bool32 MapHasPreviewScreen_HandleQLState2(u8 mapsec, u8 type)
 {
-    if (gQuestLogState == 2)
+    if (gQuestLogState == QL_STATE_2)
     {
         return FALSE;
     }
     else
     {
-        return sub_80F8110(mapsec, forceFirstTime);
+        return MapHasPreviewScreen(mapsec, type);
     }
 }
 
-void sub_80F8180(void)
+void MapPreview_InitBgs(void)
 {
     InitBgsFromTemplates(0, sMapPreviewBgTemplate, NELEMS(sMapPreviewBgTemplate));
     ShowBg(0);
 }
 
-void sub_80F819C(u8 mapsec)
+void MapPreview_LoadGfx(u8 mapsec)
 {
     u8 idx;
 
-    idx = sub_80F80E4(mapsec);
+    idx = GetMapPreviewScreenIdx(mapsec);
     if (idx != MPS_COUNT)
     {
        ResetTempTileDataBuffers();
@@ -395,55 +395,55 @@ void sub_80F819C(u8 mapsec)
        if (GetBgTilemapBuffer(0) == NULL)
        {
            SetBgTilemapBuffer(0, Alloc(BG_SCREEN_SIZE));
-           gUnknown_203ABED = TRUE;
+           sAllocedBg0TilemapBuffer = TRUE;
        }
        else
        {
-           gUnknown_203ABED = FALSE;
+           sAllocedBg0TilemapBuffer = FALSE;
        }
        CopyToBgTilemapBuffer(0, sMapPreviewScreenData[idx].tilemapptr, 0, 0x000);
        CopyBgTilemapBufferToVram(0);
     }
 }
 
-void sub_80F8234(s32 windowId)
+void MapPreview_Unload(s32 windowId)
 {
     RemoveWindow(windowId);
-    if (gUnknown_203ABED)
+    if (sAllocedBg0TilemapBuffer)
     {
         Free(GetBgTilemapBuffer(0));
     }
 }
 
-bool32 sub_80F8258(void)
+bool32 MapPreview_IsGfxLoadFinished(void)
 {
     return FreeTempTileDataBuffersIfPossible();
 }
 
-void sub_80F8268(u8 mapsec)
+void MapPreview_StartForestTransition(u8 mapsec)
 {
     u8 taskId;
 
-    taskId = CreateTask(sub_80F83D0, 0);
+    taskId = CreateTask(Task_RunMapPreviewScreenForest, 0);
     gTasks[taskId].data[2] = GetBgAttribute(0, BG_ATTR_PRIORITY);
     gTasks[taskId].data[4] = GetGpuReg(REG_OFFSET_BLDCNT);
     gTasks[taskId].data[5] = GetGpuReg(REG_OFFSET_BLDALPHA);
     gTasks[taskId].data[3] = GetGpuReg(REG_OFFSET_DISPCNT);
     gTasks[taskId].data[6] = GetGpuReg(REG_OFFSET_WININ);
     gTasks[taskId].data[7] = GetGpuReg(REG_OFFSET_WINOUT);
-    gTasks[taskId].data[10] = sub_80F856C(mapsec);
+    gTasks[taskId].data[10] = MapPreview_GetDuration(mapsec);
     gTasks[taskId].data[8] = 16;
     gTasks[taskId].data[9] = 0;
     SetBgAttribute(0, BG_ATTR_PRIORITY, 0);
     SetGpuReg(REG_OFFSET_BLDCNT, BLDCNT_TGT1_BG0 | BLDCNT_EFFECT_BLEND | BLDCNT_TGT2_BG1 | BLDCNT_TGT2_BG2 | BLDCNT_TGT2_BG3 | BLDCNT_TGT2_OBJ | BLDCNT_TGT2_BD);
     SetGpuReg(REG_OFFSET_BLDALPHA, BLDALPHA_BLEND(16, 0));
-    SetGpuRegBits(REG_OFFSET_WININ, 0x2020);
-    SetGpuRegBits(REG_OFFSET_WINOUT, 0x0020);
-    gTasks[taskId].data[11] = sub_80F8318(mapsec);
+    SetGpuRegBits(REG_OFFSET_WININ, WININ_WIN0_CLR | WININ_WIN1_CLR);
+    SetGpuRegBits(REG_OFFSET_WINOUT, WINOUT_WIN01_CLR);
+    gTasks[taskId].data[11] = MapPreview_CreateMapNameWindow(mapsec);
     ScriptContext2_Enable();
 }
 
-u16 sub_80F8318(u8 mapsec)
+u16 MapPreview_CreateMapNameWindow(u8 mapsec)
 {
     u16 windowId;
     u32 xctr;
@@ -452,18 +452,18 @@ u16 sub_80F8318(u8 mapsec)
     windowId = AddWindow(&sMapNameWindow);
     FillWindowPixelBuffer(windowId, PIXEL_FILL(1));
     PutWindowTilemap(windowId);
-    color[0] = 1; // Access violation
-    color[1] = 4; // Access violation
-    color[2] = 3; // Access violation
+    color[0] = TEXT_COLOR_WHITE; // Access violation
+    color[1] = TEXT_COLOR_RED; // Access violation
+    color[2] = TEXT_COLOR_LIGHT_GREY; // Access violation
     GetMapName(gStringVar4, mapsec, 0);
     xctr = 104 - GetStringWidth(2, gStringVar4, 0);
     AddTextPrinterParameterized4(windowId, 2, xctr / 2, 2, 0, 0, color/* Access violation */, -1, gStringVar4);
     return windowId;
 }
 
-bool32 sub_80F83B0(void)
+bool32 ForestMapPreviewScreenIsRunning(void)
 {
-    if (FuncIsActiveTask(sub_80F83D0) == TRUE)
+    if (FuncIsActiveTask(Task_RunMapPreviewScreenForest) == TRUE)
     {
         return FALSE;
     }
@@ -473,7 +473,7 @@ bool32 sub_80F83B0(void)
     }
 }
 
-static void sub_80F83D0(u8 taskId)
+static void Task_RunMapPreviewScreenForest(u8 taskId)
 {
     s16 * data;
 
@@ -481,7 +481,7 @@ static void sub_80F83D0(u8 taskId)
     switch (data[0])
     {
     case 0:
-        if (!sub_80F8258() && !IsDma3ManagerBusyWithBgCopy())
+        if (!MapPreview_IsGfxLoadFinished() && !IsDma3ManagerBusyWithBgCopy())
         {
             CopyWindowToVram(data[11], 3);
             data[0]++;
@@ -539,7 +539,7 @@ static void sub_80F83D0(u8 taskId)
     case 5:
         if (!IsDma3ManagerBusyWithBgCopy())
         {
-            sub_80F8234(data[11]);
+            MapPreview_Unload(data[11]);
             SetBgAttribute(0, BG_ATTR_PRIORITY, data[2]);
             SetGpuReg(REG_OFFSET_DISPCNT, data[3]);
             SetGpuReg(REG_OFFSET_BLDCNT, data[4]);
@@ -556,7 +556,7 @@ const struct MapPreviewScreen * GetDungeonMapPreviewScreenInfo(u8 mapsec)
 {
     u8 idx;
 
-    idx = sub_80F80E4(mapsec);
+    idx = GetMapPreviewScreenIdx(mapsec);
     if (idx == MPS_COUNT)
     {
         return NULL;
@@ -567,18 +567,18 @@ const struct MapPreviewScreen * GetDungeonMapPreviewScreenInfo(u8 mapsec)
     }
 }
 
-u16 sub_80F856C(u8 mapsec)
+u16 MapPreview_GetDuration(u8 mapsec)
 {
     u8 idx;
     u16 flagId;
 
-    idx = sub_80F80E4(mapsec);
+    idx = GetMapPreviewScreenIdx(mapsec);
     if (idx == MPS_COUNT)
     {
         return 0;
     }
     flagId = sMapPreviewScreenData[idx].flagId;
-    if (!sMapPreviewScreenData[idx].forceFirstTime)
+    if (sMapPreviewScreenData[idx].type == MPS_TYPE_CAVE)
     {
         if (!FlagGet(flagId))
         {
@@ -590,7 +590,7 @@ u16 sub_80F856C(u8 mapsec)
         }
     }
     else {
-        if (gUnknown_203ABEC)
+        if (sHasVisitedMapBefore)
         {
             return 120;
         }
@@ -601,15 +601,15 @@ u16 sub_80F856C(u8 mapsec)
     }
 }
 
-void sub_80F85BC(u16 flagId)
+void MapPreview_SetFlag(u16 flagId)
 {
     if (!FlagGet(flagId))
     {
-        gUnknown_203ABEC = TRUE;
+        sHasVisitedMapBefore = TRUE;
     }
     else
     {
-        gUnknown_203ABEC = FALSE;
+        sHasVisitedMapBefore = FALSE;
     }
     FlagSet(flagId);
 }
diff --git a/src/player_pc.c b/src/player_pc.c
index 62a899e39..736c67a51 100644
--- a/src/player_pc.c
+++ b/src/player_pc.c
@@ -23,6 +23,7 @@
 #include "party_menu.h"
 #include "constants/items.h"
 #include "constants/songs.h"
+#include "constants/field_weather.h"
 
 #define PC_ITEM_ID  0
 #define PC_QUANTITY 1
@@ -331,7 +332,7 @@ static void Task_DepositItem_WaitFadeAndGoToBag(u8 taskId)
 static void Task_PlayerPcDepositItem(u8 taskId)
 {
     gTasks[taskId].func = Task_DepositItem_WaitFadeAndGoToBag;
-    FadeScreen(1, 0);
+    FadeScreen(FADE_TO_BLACK, 0);
 }
 
 static void Task_ReturnToItemStorageSubmenu(u8 taskId)
@@ -394,7 +395,7 @@ static void Task_WithdrawItemBeginFade(u8 taskId)
 {
     gTasks[taskId].func = Task_WithdrawItem_WaitFadeAndGoToItemStorage;
     ItemPc_SetInitializedFlag(0);
-    FadeScreen(1, 0);
+    FadeScreen(FADE_TO_BLACK, 0);
 }
 
 static void Task_PlayerPcCancel(u8 taskId)
@@ -556,7 +557,7 @@ static void Task_MailSubmenuHandleInput(u8 taskId)
 
 static void Task_PlayerPcReadMail(u8 taskId)
 {
-    FadeScreen(1, 0);
+    FadeScreen(FADE_TO_BLACK, 0);
     gTasks[taskId].func = Task_WaitFadeAndReadSelectedMail;
 }
 
@@ -663,7 +664,7 @@ static void Task_PlayerPcGiveMailToMon(u8 taskId)
     }
     else
     {
-        FadeScreen(1, 0);
+        FadeScreen(FADE_TO_BLACK, 0);
         gTasks[taskId].func = Task_WaitFadeAndGoToPartyMenu;
     }
 }
diff --git a/src/quest_log.c b/src/quest_log.c
index 5d260b58f..91c07223e 100644
--- a/src/quest_log.c
+++ b/src/quest_log.c
@@ -42,6 +42,7 @@
 #include "constants/trainer_classes.h"
 #include "constants/species.h"
 #include "constants/items.h"
+#include "constants/field_weather.h"
 
 u8 gUnknown_3005E88;
 
@@ -152,7 +153,7 @@ static u8 sub_8111BD4(void);
 static void DrawQuestLogSceneDescription(void);
 static void sub_8111D90(u8);
 static void QuestLog_CloseTextWindow(void);
-static void QuestLog_SkipToEndOfPlayback(s8);
+static void QuestLog_SkipToEndOfPlayback(s8 delay);
 static void QuestLog_WaitFadeAndCancelPlayback(void);
 static bool8 sub_8111F60(void);
 static void sub_8111F8C(u8);
@@ -920,7 +921,7 @@ static void sub_811175C(u8 sceneNum, struct UnkStruct_203AE98 * a1)
 
 static void sub_81118F4(s8 a0)
 {
-    FadeScreen(1, a0);
+    FadeScreen(FADE_TO_BLACK, a0);
     sQuestLogCB = QuestLog_AdvancePlayhead;
 }
 
@@ -1178,9 +1179,9 @@ static void QuestLog_CloseTextWindow(void)
     CopyWindowToVram(gUnknown_203ADFE[1], 1);
 }
 
-static void QuestLog_SkipToEndOfPlayback(s8 a0)
+static void QuestLog_SkipToEndOfPlayback(s8 delay)
 {
-    FadeScreen(1, a0);
+    FadeScreen(FADE_TO_BLACK, delay);
     sQuestLogCB = QuestLog_WaitFadeAndCancelPlayback;
 }
 
@@ -4294,7 +4295,7 @@ static const u16 sQuestLogWorldMapFlags[] =
     FLAG_WORLD_MAP_SIX_ISLAND
 };
 
-void sub_8115748(u16 worldMapFlag)
+void QuestLog_RecordEnteredMap(u16 worldMapFlag)
 {
     s32 i;
 
diff --git a/src/scrcmd.c b/src/scrcmd.c
index b4605e9d5..7eaa98c76 100644
--- a/src/scrcmd.c
+++ b/src/scrcmd.c
@@ -598,8 +598,8 @@ bool8 ScrCmd_comparestattoword(struct ScriptContext * ctx)
 bool8 ScrCmd_setworldmapflag(struct ScriptContext * ctx)
 {
     u16 value = ScriptReadHalfword(ctx);
-    sub_8115748(value);
-    sub_80F85BC(value);
+    QuestLog_RecordEnteredMap(value);
+    MapPreview_SetFlag(value);
     return FALSE;
 }
 
diff --git a/src/shop.c b/src/shop.c
index 5cc9ab3f0..ddeaf6a68 100644
--- a/src/shop.c
+++ b/src/shop.c
@@ -36,6 +36,7 @@
 #include "constants/songs.h"
 #include "constants/items.h"
 #include "constants/game_stat.h"
+#include "constants/field_weather.h"
 
 #define tItemCount data[1]
 #define tItemId data[5]
@@ -292,14 +293,14 @@ static void Task_ShopMenu(u8 taskId)
 static void Task_HandleShopMenuBuy(u8 taskId)
 {
     SetWordTaskArg(taskId, 0xE, (u32)CB2_InitBuyMenu);
-    FadeScreen(1, 0);
+    FadeScreen(FADE_TO_BLACK, 0);
     gTasks[taskId].func = Task_GoToBuyOrSellMenu;
 }
 
 static void Task_HandleShopMenuSell(u8 taskId)
 {
     SetWordTaskArg(taskId, 0xE, (u32)CB2_GoToSellMenu);
-    FadeScreen(1, 0);
+    FadeScreen(FADE_TO_BLACK, 0);
     gTasks[taskId].func = Task_GoToBuyOrSellMenu;    
 }
 
diff --git a/src/start_menu.c b/src/start_menu.c
index cf8be2de9..867e469e0 100644
--- a/src/start_menu.c
+++ b/src/start_menu.c
@@ -39,6 +39,7 @@
 #include "help_system.h"
 #include "constants/songs.h"
 #include "constants/flags.h"
+#include "constants/field_weather.h"
 
 enum StartMenuOption
 {
@@ -446,7 +447,7 @@ static void StartMenu_FadeScreenIfLeavingOverworld(void)
      && sStartMenuCallback != StartMenuSafariZoneRetireCallback)
     {
         StopPokemonLeagueLightingEffectTask();
-        FadeScreen(1, 0);
+        FadeScreen(FADE_TO_BLACK, 0);
     }
 }