shake screen functions

6 files changed, 39 insertions, 33 deletions

diff --git a/engine/battle/animations.asm b/engine/battle/animations.asm
index 939c8db0..8b3b9147 100755
--- a/engine/battle/animations.asm
+++ b/engine/battle/animations.asm
@@ -835,9 +835,9 @@ DoRockSlideSpecialEffects: ; 78fd9 (1e:4fd9)
 ; if the subaninmation counter is between 8 and 11, shake the screen horizontally and vertically
 .shakeScreen
 	ld b,1
-	predef Func_48125 ; shake horizontally
+	predef PredefShakeScreenHorizontally ; shake horizontally
 	ld b,1
-	predef_jump Func_480ff ; shake vertically
+	predef_jump PredefShakeScreenVertically ; shake vertically
 
 FlashScreenEveryEightFrameBlocks: ; 78ff7 (1e:4ff7)
 	ld a,[W_SUBANIMCOUNTER]
@@ -1225,14 +1225,14 @@ SetAnimationBGPalette: ; 791fc (1e:51fc)
 	ld b, $5
 
 AnimationShakeScreenVertically: ; 79209 (1e:5209)
-	predef_jump Func_480ff
+	predef_jump PredefShakeScreenVertically
 
 AnimationShakeScreen: ; 7920e (1e:520e)
 ; Shakes the screen for a while. Used in Earthquake/Fissure/etc. animations.
 	ld b, $8
 
 AnimationShakeScreenHorizontallyFast: ; 79210 (1e:5210)
-	predef_jump Func_48125
+	predef_jump PredefShakeScreenHorizontally
 
 AnimationWaterDropletsEverywhere: ; 79215 (1e:5215)
 ; Draws water droplets all over the screen and makes them
diff --git a/engine/battle/core.asm b/engine/battle/core.asm
index db1ebd32..364b184b 100755
--- a/engine/battle/core.asm
+++ b/engine/battle/core.asm
@@ -3958,7 +3958,7 @@ PrintMoveFailureText: ; 3dbe2 (f:5be2)
 	ld hl, KeptGoingAndCrashedText
 	call PrintText
 	ld b, $4
-	predef Func_48125
+	predef PredefShakeScreenHorizontally
 	ld a, [H_WHOSETURN]
 	and a
 	jr nz, .enemyTurn
diff --git a/engine/predefs.asm b/engine/predefs.asm
index 90065d51..a8aba971 100755
--- a/engine/predefs.asm
+++ b/engine/predefs.asm
@@ -85,10 +85,10 @@ PredefPointers:: ; 4fe79 (13:7e79)
 	dbw $03,GiveItem
 	add_predef ChangeBGPalColor0_4Frames
 	add_predef FindPathToPlayer
-	add_predef Func_480ff
+	add_predef PredefShakeScreenVertically
 	add_predef CalcPositionOfPlayerRelativeToNPC
 	add_predef ConvertNPCMovementDirectionsToJoypadMasks
-	add_predef Func_48125
+	add_predef PredefShakeScreenHorizontally
 	add_predef UpdateHPBar
 	add_predef HPBarLength
 	add_predef Diploma_TextBoxBorder
diff --git a/engine/predefs12.asm b/engine/predefs12.asm
index f318447e..9731134f 100755
--- a/engine/predefs12.asm
+++ b/engine/predefs12.asm
@@ -4,62 +4,68 @@ ChangeBGPalColor0_4Frames: ; 480eb (12:40eb)
 	ld a, [rBGP]
 	or b
 	ld [rBGP], a
-	ld c, 4
+	ld c, $4
 	call DelayFrames
 	ld a, [rBGP]
 	and %11111100
 	ld [rBGP], a
 	ret
 
-Func_480ff: ; 480ff (12:40ff)
+PredefShakeScreenVertically: ; 480ff (12:40ff)
+; Moves the window down and then back in a sequence of progressively smaller
+; numbers of pixels, starting at b.
 	call GetPredefRegisters
-	ld a, $1
-	ld [wd0a0], a
+	ld a, 1
+	ld [wDisableVBlankWYUpdate], a
 	xor a
-.asm_48108
-	ld [H_NUMTOPRINT], a ; (aliases: H_MULTIPLICAND)
-	call Func_48119
-	call Func_48119
+.loop
+	ld [$ff96], a
+	call .MutateWY
+	call .MutateWY
 	dec b
 	ld a, b
-	jr nz, .asm_48108
+	jr nz, .loop
 	xor a
-	ld [wd0a0], a
+	ld [wDisableVBlankWYUpdate], a
 	ret
 
-Func_48119: ; 48119 (12:4119)
-	ld a, [H_NUMTOPRINT] ; (aliases: H_MULTIPLICAND)
+.MutateWY ; 48119 (12:4119)
+	ld a, [$ff96]
 	xor b
-	ld [H_NUMTOPRINT], a ; (aliases: H_MULTIPLICAND)
+	ld [$ff96], a
 	ld [rWY], a
 	ld c, 3
 	jp DelayFrames
 
-Func_48125: ; 48125 (12:4125)
+PredefShakeScreenHorizontally: ; 48125 (12:4125)
+; Moves the window right and then back in a sequence of progressively smaller
+; numbers of pixels, starting at b.
 	call GetPredefRegisters
 	xor a
-.asm_48129
+.loop
 	ld [$ff97], a
-	call Func_4813f
+	call .MutateWX
 	ld c, 1
 	call DelayFrames
-	call Func_4813f
+	call .MutateWX
 	dec b
 	ld a, b
-	jr nz, .asm_48129
-	ld a, $7
+	jr nz, .loop
+
+; restore normal WX
+	ld a, 7
 	ld [rWX], a
 	ret
 
-Func_4813f: ; 4813f (12:413f)
+.MutateWX ; 4813f (12:413f)
 	ld a, [$ff97]
 	xor b
 	ld [$ff97], a
 	bit 7, a
-	jr z, .asm_48149
-	xor a
-.asm_48149
-	add $7
+	jr z, .skipZeroing
+	xor a ; zero a if it's negative
+.skipZeroing
+	add 7
 	ld [rWX], a
 	ld c, 4
 	jp DelayFrames
diff --git a/home/vblank.asm b/home/vblank.asm
index d8288187..9adf537c 100644
--- a/home/vblank.asm
+++ b/home/vblank.asm
@@ -13,7 +13,7 @@ VBlank::
 	ld a, [hSCY]
 	ld [rSCY], a
 
-	ld a, [wd0a0]
+	ld a, [wDisableVBlankWYUpdate]
 	and a
 	jr nz, .ok
 	ld a, [hWY]
diff --git a/wram.asm b/wram.asm
index 2fbbd7ec..83aa4e60 100755
--- a/wram.asm
+++ b/wram.asm
@@ -1223,7 +1223,7 @@ W_FBMODE:: ; d09e
 wNewTileBlockID:: ; d09f
 
 wd09f:: ds 1 ; used with predef ReplaceTileBlock
-wd0a0:: ds 1 ; used in VBlank and ChangeBGPalColor0_4Frames
+wDisableVBlankWYUpdate:: ds 1 ; if non-zero, don't update WY during V-blank
 
 W_SPRITECURPOSX:: ; d0a1
 	ds 1