Merge branch 'master' into doc-frontierpass2

1 files changed, 344 insertions, 255 deletions

diff --git a/src/field_effect_helpers.c b/src/field_effect_helpers.c
index 67102a83b..eab7d85ef 100755
--- a/src/field_effect_helpers.c
+++ b/src/field_effect_helpers.c
@@ -19,19 +19,22 @@ static void UpdateObjectReflectionSprite(struct Sprite *);
 static void LoadObjectReflectionPalette(struct ObjectEvent *objectEvent, struct Sprite *sprite);
 static void LoadObjectHighBridgeReflectionPalette(struct ObjectEvent *, u8);
 static void LoadObjectRegularReflectionPalette(struct ObjectEvent *, u8);
-static void sub_81561FC(struct Sprite *, u8, u8);
+static void UpdateGrassFieldEffectSubpriority(struct Sprite *, u8, u8);
 static void FadeFootprintsTireTracks_Step0(struct Sprite *);
 static void FadeFootprintsTireTracks_Step1(struct Sprite *);
 static void UpdateFeetInFlowingWaterFieldEffect(struct Sprite *);
-static void UpdateAshFieldEffect_Step0(struct Sprite *);
-static void UpdateAshFieldEffect_Step1(struct Sprite *);
-static void UpdateAshFieldEffect_Step2(struct Sprite *);
+static void UpdateAshFieldEffect_Wait(struct Sprite *);
+static void UpdateAshFieldEffect_Show(struct Sprite *);
+static void UpdateAshFieldEffect_End(struct Sprite *);
 static void SynchroniseSurfAnim(struct ObjectEvent *, struct Sprite *);
-static void sub_81556E8(struct ObjectEvent *, struct Sprite *);
-static void CreateBobbingEffect(struct ObjectEvent *, struct Sprite *, struct Sprite *);
-static void sub_8155850(struct Sprite *);
+static void SynchroniseSurfPosition(struct ObjectEvent *, struct Sprite *);
+static void UpdateBobbingEffect(struct ObjectEvent *, struct Sprite *, struct Sprite *);
+static void SpriteCB_UnderwaterSurfBlob(struct Sprite *);
 static u32 ShowDisguiseFieldEffect(u8, u8, u8);
 
+// Used by several field effects to determine which of a group it is
+#define sFldEff    data[1]
+
 #define sReflectionObjEventId       data[0]
 #define sReflectionObjEventLocalId  data[1]
 #define sReflectionVerticalOffset   data[2] 
@@ -41,7 +44,7 @@ void SetUpReflection(struct ObjectEvent *objectEvent, struct Sprite *sprite, boo
 {
     struct Sprite *reflectionSprite;
 
-    reflectionSprite = &gSprites[CreateCopySpriteAt(sprite, sprite->pos1.x, sprite->pos1.y, 0x98)];
+    reflectionSprite = &gSprites[CreateCopySpriteAt(sprite, sprite->x, sprite->y, 0x98)];
     reflectionSprite->callback = UpdateObjectReflectionSprite;
     reflectionSprite->oam.priority = 3;
     reflectionSprite->oam.paletteNum = gReflectionEffectPaletteMap[reflectionSprite->oam.paletteNum];
@@ -139,12 +142,12 @@ static void UpdateObjectReflectionSprite(struct Sprite *reflectionSprite)
         reflectionSprite->subspriteTables = mainSprite->subspriteTables;
         reflectionSprite->subspriteTableNum = mainSprite->subspriteTableNum;
         reflectionSprite->invisible = mainSprite->invisible;
-        reflectionSprite->pos1.x = mainSprite->pos1.x;
-        reflectionSprite->pos1.y = mainSprite->pos1.y + GetReflectionVerticalOffset(objectEvent) + reflectionSprite->sReflectionVerticalOffset;
+        reflectionSprite->x = mainSprite->x;
+        reflectionSprite->y = mainSprite->y + GetReflectionVerticalOffset(objectEvent) + reflectionSprite->sReflectionVerticalOffset;
         reflectionSprite->centerToCornerVecX = mainSprite->centerToCornerVecX;
         reflectionSprite->centerToCornerVecY = mainSprite->centerToCornerVecY;
-        reflectionSprite->pos2.x = mainSprite->pos2.x;
-        reflectionSprite->pos2.y = -mainSprite->pos2.y;
+        reflectionSprite->x2 = mainSprite->x2;
+        reflectionSprite->y2 = -mainSprite->y2;
         reflectionSprite->coordOffsetEnabled = mainSprite->coordOffsetEnabled;
 
         if (objectEvent->hideReflection == TRUE)
@@ -201,8 +204,8 @@ void ShowWarpArrowSprite(u8 spriteId, u8 direction, s16 x, s16 y)
     {
         SetSpritePosToMapCoords(x, y, &x2, &y2);
         sprite = &gSprites[spriteId];
-        sprite->pos1.x = x2 + 8;
-        sprite->pos1.y = y2 + 8;
+        sprite->x = x2 + 8;
+        sprite->y = y2 + 8;
         sprite->invisible = FALSE;
         sprite->data[0] = x;
         sprite->data[1] = y;
@@ -259,8 +262,8 @@ void UpdateShadowFieldEffect(struct Sprite *sprite)
         objectEvent = &gObjectEvents[objectEventId];
         linkedSprite = &gSprites[objectEvent->spriteId];
         sprite->oam.priority = linkedSprite->oam.priority;
-        sprite->pos1.x = linkedSprite->pos1.x;
-        sprite->pos1.y = linkedSprite->pos1.y + sprite->data[3];
+        sprite->x = linkedSprite->x;
+        sprite->y = linkedSprite->y + sprite->data[3];
         if (!objectEvent->active || !objectEvent->hasShadow
          || MetatileBehavior_IsPokeGrass(objectEvent->currentMetatileBehavior)
          || MetatileBehavior_IsSurfableWaterOrUnderwater(objectEvent->currentMetatileBehavior)
@@ -273,6 +276,16 @@ void UpdateShadowFieldEffect(struct Sprite *sprite)
     }
 }
 
+// Sprite data for FLDEFF_TALL_GRASS and FLDEFF_LONG_GRASS
+#define sElevation   data[0]
+#define sX           data[1]
+#define sY           data[2]
+#define sMapNum      data[3]      // Lower 8 bits
+#define sLocalId     data[3] >> 8 // Upper 8 bits
+#define sMapGroup    data[4]
+#define sCurrentMap  data[5]
+#define sObjectMoved data[7]
+
 u32 FldEff_TallGrass(void)
 {
     s16 x;
@@ -289,16 +302,15 @@ u32 FldEff_TallGrass(void)
         sprite = &gSprites[spriteId];
         sprite->coordOffsetEnabled = TRUE;
         sprite->oam.priority = gFieldEffectArguments[3];
-        sprite->data[0] = gFieldEffectArguments[2];
-        sprite->data[1] = gFieldEffectArguments[0];
-        sprite->data[2] = gFieldEffectArguments[1];
-        sprite->data[3] = gFieldEffectArguments[4];
-        sprite->data[4] = gFieldEffectArguments[5];
-        sprite->data[5] = gFieldEffectArguments[6];
+        sprite->sElevation = gFieldEffectArguments[2];
+        sprite->sX = gFieldEffectArguments[0];
+        sprite->sY = gFieldEffectArguments[1];
+        sprite->sMapNum = gFieldEffectArguments[4]; // Also sLocalId
+        sprite->sMapGroup = gFieldEffectArguments[5];
+        sprite->sCurrentMap = gFieldEffectArguments[6];
+
         if (gFieldEffectArguments[7])
-        {
-            SeekSpriteAnim(sprite, 4);
-        }
+            SeekSpriteAnim(sprite, 4); // Skip to end of anim
     }
     return 0;
 }
@@ -312,34 +324,42 @@ void UpdateTallGrassFieldEffect(struct Sprite *sprite)
     u8 objectEventId;
     struct ObjectEvent *objectEvent;
 
-    mapNum = sprite->data[5] >> 8;
-    mapGroup = sprite->data[5];
+    mapNum = sprite->sCurrentMap >> 8;
+    mapGroup = sprite->sCurrentMap;
     if (gCamera.active && (gSaveBlock1Ptr->location.mapNum != mapNum || gSaveBlock1Ptr->location.mapGroup != mapGroup))
     {
-        sprite->data[1] -= gCamera.x;
-        sprite->data[2] -= gCamera.y;
-        sprite->data[5] = ((u8)gSaveBlock1Ptr->location.mapNum << 8) | (u8)gSaveBlock1Ptr->location.mapGroup;
+        sprite->sX -= gCamera.x;
+        sprite->sY -= gCamera.y;
+        sprite->sCurrentMap = ((u8)gSaveBlock1Ptr->location.mapNum << 8) | (u8)gSaveBlock1Ptr->location.mapGroup;
     }
-    localId = sprite->data[3] >> 8;
-    mapNum = sprite->data[3];
-    mapGroup = sprite->data[4];
-    metatileBehavior = MapGridGetMetatileBehaviorAt(sprite->data[1], sprite->data[2]);
-    if (TryGetObjectEventIdByLocalIdAndMap(localId, mapNum, mapGroup, &objectEventId) || !MetatileBehavior_IsTallGrass(metatileBehavior) || (sprite->data[7] && sprite->animEnded))
+    localId = sprite->sLocalId;
+    mapNum = sprite->sMapNum;
+    mapGroup = sprite->sMapGroup;
+    metatileBehavior = MapGridGetMetatileBehaviorAt(sprite->sX, sprite->sY);
+
+    if (TryGetObjectEventIdByLocalIdAndMap(localId, mapNum, mapGroup, &objectEventId) 
+     || !MetatileBehavior_IsTallGrass(metatileBehavior) 
+     || (sprite->sObjectMoved && sprite->animEnded))
     {
         FieldEffectStop(sprite, FLDEFF_TALL_GRASS);
     }
     else
     {
+        // Check if the object that triggered the effect has moved away
         objectEvent = &gObjectEvents[objectEventId];
-        if ((objectEvent->currentCoords.x != sprite->data[1] || objectEvent->currentCoords.y != sprite->data[2]) && (objectEvent->previousCoords.x != sprite->data[1] || objectEvent->previousCoords.y != sprite->data[2]))
-            sprite->data[7] = TRUE;
+        if ((objectEvent->currentCoords.x != sprite->sX 
+          || objectEvent->currentCoords.y != sprite->sY) 
+        && (objectEvent->previousCoords.x != sprite->sX
+         || objectEvent->previousCoords.y != sprite->sY))
+            sprite->sObjectMoved = TRUE;
 
+        // Metatile behavior var re-used
         metatileBehavior = 0;
         if (sprite->animCmdIndex == 0)
             metatileBehavior = 4;
 
-        UpdateObjectEventSpriteVisibility(sprite, 0);
-        sub_81561FC(sprite, sprite->data[0], metatileBehavior);
+        UpdateObjectEventSpriteInvisibility(sprite, FALSE);
+        UpdateGrassFieldEffectSubpriority(sprite, sprite->sElevation, metatileBehavior);
     }
 }
 
@@ -355,8 +375,8 @@ u32 FldEff_JumpTallGrass(void)
         sprite = &gSprites[spriteId];
         sprite->coordOffsetEnabled = TRUE;
         sprite->oam.priority = gFieldEffectArguments[3];
-        sprite->data[0] = gFieldEffectArguments[2];
-        sprite->data[1] = FLDEFF_JUMP_TALL_GRASS;
+        sprite->sElevation = gFieldEffectArguments[2];
+        sprite->sFldEff = FLDEFF_JUMP_TALL_GRASS;
     }
     return 0;
 }
@@ -371,11 +391,14 @@ u8 FindTallGrassFieldEffectSpriteId(u8 localId, u8 mapNum, u8 mapGroup, s16 x, s
         if (gSprites[i].inUse)
         {
             sprite = &gSprites[i];
-            if (sprite->callback == UpdateTallGrassFieldEffect && (x == sprite->data[1] && y == sprite->data[2]) && (localId == (u8)(sprite->data[3] >> 8) && mapNum == (sprite->data[3] & 0xFF) && mapGroup == sprite->data[4]))
+            if (sprite->callback == UpdateTallGrassFieldEffect 
+                && (x == sprite->sX && y == sprite->sY) 
+                && localId == (u8)(sprite->sLocalId) 
+                && mapNum == (sprite->sMapNum & 0xFF) 
+                && mapGroup == sprite->sMapGroup)
                 return i;
         }
     }
-
     return MAX_SPRITES;
 }
 
@@ -395,16 +418,15 @@ u32 FldEff_LongGrass(void)
         sprite = &gSprites[spriteId];
         sprite->coordOffsetEnabled = TRUE;
         sprite->oam.priority = ZCoordToPriority(gFieldEffectArguments[2]);
-        sprite->data[0] = gFieldEffectArguments[2];
-        sprite->data[1] = gFieldEffectArguments[0];
-        sprite->data[2] = gFieldEffectArguments[1];
-        sprite->data[3] = gFieldEffectArguments[4];
-        sprite->data[4] = gFieldEffectArguments[5];
-        sprite->data[5] = gFieldEffectArguments[6];
+        sprite->sElevation = gFieldEffectArguments[2];
+        sprite->sX = gFieldEffectArguments[0];
+        sprite->sY = gFieldEffectArguments[1];
+        sprite->sMapNum = gFieldEffectArguments[4]; // Also sLocalId
+        sprite->sMapGroup = gFieldEffectArguments[5];
+        sprite->sCurrentMap = gFieldEffectArguments[6];
+
         if (gFieldEffectArguments[7])
-        {
-            SeekSpriteAnim(sprite, 6);
-        }
+            SeekSpriteAnim(sprite, 6); // Skip to end of anim
     }
     return 0;
 }
@@ -418,34 +440,47 @@ void UpdateLongGrassFieldEffect(struct Sprite *sprite)
     u8 objectEventId;
     struct ObjectEvent *objectEvent;
 
-    mapNum = sprite->data[5] >> 8;
-    mapGroup = sprite->data[5];
+    mapNum = sprite->sCurrentMap >> 8;
+    mapGroup = sprite->sCurrentMap;
     if (gCamera.active && (gSaveBlock1Ptr->location.mapNum != mapNum || gSaveBlock1Ptr->location.mapGroup != mapGroup))
     {
-        sprite->data[1] -= gCamera.x;
-        sprite->data[2] -= gCamera.y;
-        sprite->data[5] = ((u8)gSaveBlock1Ptr->location.mapNum << 8) | (u8)gSaveBlock1Ptr->location.mapGroup;
+        sprite->sX -= gCamera.x;
+        sprite->sY -= gCamera.y;
+        sprite->sCurrentMap = ((u8)gSaveBlock1Ptr->location.mapNum << 8) | (u8)gSaveBlock1Ptr->location.mapGroup;
     }
-    localId = sprite->data[3] >> 8;
-    mapNum = sprite->data[3];
-    mapGroup = sprite->data[4];
+    localId = sprite->sLocalId;
+    mapNum = sprite->sMapNum;
+    mapGroup = sprite->sMapGroup;
     metatileBehavior = MapGridGetMetatileBehaviorAt(sprite->data[1], sprite->data[2]);
-    if (TryGetObjectEventIdByLocalIdAndMap(localId, mapNum, mapGroup, &objectEventId) || !MetatileBehavior_IsLongGrass(metatileBehavior) || (sprite->data[7] && sprite->animEnded))
+    if (TryGetObjectEventIdByLocalIdAndMap(localId, mapNum, mapGroup, &objectEventId) 
+     || !MetatileBehavior_IsLongGrass(metatileBehavior) 
+     || (sprite->sObjectMoved && sprite->animEnded))
     {
         FieldEffectStop(sprite, FLDEFF_LONG_GRASS);
     }
     else
     {
+        // Check if the object that triggered the effect has moved away
         objectEvent = &gObjectEvents[objectEventId];
-        if ((objectEvent->currentCoords.x != sprite->data[1] || objectEvent->currentCoords.y != sprite->data[2]) && (objectEvent->previousCoords.x != sprite->data[1] || objectEvent->previousCoords.y != sprite->data[2]))
-        {
-            sprite->data[7] = TRUE;
-        }
-        UpdateObjectEventSpriteVisibility(sprite, 0);
-        sub_81561FC(sprite, sprite->data[0], 0);
+        if ((objectEvent->currentCoords.x != sprite->data[1] 
+          || objectEvent->currentCoords.y != sprite->data[2]) 
+        && (objectEvent->previousCoords.x != sprite->data[1] 
+         || objectEvent->previousCoords.y != sprite->data[2]))
+            sprite->sObjectMoved = TRUE;
+
+        UpdateObjectEventSpriteInvisibility(sprite, FALSE);
+        UpdateGrassFieldEffectSubpriority(sprite, sprite->sElevation, 0);
     }
 }
 
+#undef sX
+#undef sY
+#undef sMapNum
+#undef sLocalId
+#undef sMapGroup
+#undef sCurrentMap
+#undef sObjectMoved
+
 u32 FldEff_JumpLongGrass(void)
 {
     u8 spriteId;
@@ -458,8 +493,8 @@ u32 FldEff_JumpLongGrass(void)
         sprite = &gSprites[spriteId];
         sprite->coordOffsetEnabled = TRUE;
         sprite->oam.priority = gFieldEffectArguments[3];
-        sprite->data[0] = gFieldEffectArguments[2];
-        sprite->data[1] = FLDEFF_JUMP_LONG_GRASS;
+        sprite->sElevation = gFieldEffectArguments[2];
+        sprite->sFldEff = FLDEFF_JUMP_LONG_GRASS;
     }
     return 0;
 }
@@ -482,8 +517,8 @@ u32 FldEff_ShortGrass(void)
         sprite->data[0] = gFieldEffectArguments[0];
         sprite->data[1] = gFieldEffectArguments[1];
         sprite->data[2] = gFieldEffectArguments[2];
-        sprite->data[3] = gSprites[objectEvent->spriteId].pos1.x;
-        sprite->data[4] = gSprites[objectEvent->spriteId].pos1.y;
+        sprite->data[3] = gSprites[objectEvent->spriteId].x;
+        sprite->data[4] = gSprites[objectEvent->spriteId].y;
     }
     return 0;
 }
@@ -504,8 +539,8 @@ void UpdateShortGrassFieldEffect(struct Sprite *sprite)
     {
         graphicsInfo = GetObjectEventGraphicsInfo(gObjectEvents[objectEventId].graphicsId);
         linkedSprite = &gSprites[gObjectEvents[objectEventId].spriteId];
-        y = linkedSprite->pos1.y;
-        x = linkedSprite->pos1.x;
+        y = linkedSprite->y;
+        x = linkedSprite->x;
         if (x != sprite->data[3] || y != sprite->data[4])
         {
             sprite->data[3] = x;
@@ -515,12 +550,12 @@ void UpdateShortGrassFieldEffect(struct Sprite *sprite)
                 StartSpriteAnim(sprite, 0);
             }
         }
-        sprite->pos1.x = x;
-        sprite->pos1.y = y;
-        sprite->pos2.y = (graphicsInfo->height >> 1) - 8;
+        sprite->x = x;
+        sprite->y = y;
+        sprite->y2 = (graphicsInfo->height >> 1) - 8;
         sprite->subpriority = linkedSprite->subpriority - 1;
         sprite->oam.priority = linkedSprite->oam.priority;
-        UpdateObjectEventSpriteVisibility(sprite, linkedSprite->invisible);
+        UpdateObjectEventSpriteInvisibility(sprite, linkedSprite->invisible);
     }
 }
 
@@ -594,14 +629,14 @@ static void FadeFootprintsTireTracks_Step0(struct Sprite *sprite)
     if (++sprite->data[1] > 40)
         sprite->data[0] = 1;
 
-    UpdateObjectEventSpriteVisibility(sprite, FALSE);
+    UpdateObjectEventSpriteInvisibility(sprite, FALSE);
 }
 
 static void FadeFootprintsTireTracks_Step1(struct Sprite *sprite)
 {
     sprite->invisible ^= 1;
     sprite->data[1]++;
-    UpdateObjectEventSpriteVisibility(sprite, sprite->invisible);
+    UpdateObjectEventSpriteInvisibility(sprite, sprite->invisible);
     if (sprite->data[1] > 56)
     {
         FieldEffectStop(sprite, sprite->data[7]);
@@ -630,7 +665,7 @@ u32 FldEff_Splash(void)
         sprite->data[0] = gFieldEffectArguments[0];
         sprite->data[1] = gFieldEffectArguments[1];
         sprite->data[2] = gFieldEffectArguments[2];
-        sprite->pos2.y = (graphicsInfo->height >> 1) - 4;
+        sprite->y2 = (graphicsInfo->height >> 1) - 4;
         PlaySE(SE_PUDDLE);
     }
     return 0;
@@ -646,9 +681,9 @@ void UpdateSplashFieldEffect(struct Sprite *sprite)
     }
     else
     {
-        sprite->pos1.x = gSprites[gObjectEvents[objectEventId].spriteId].pos1.x;
-        sprite->pos1.y = gSprites[gObjectEvents[objectEventId].spriteId].pos1.y;
-        UpdateObjectEventSpriteVisibility(sprite, FALSE);
+        sprite->x = gSprites[gObjectEvents[objectEventId].spriteId].x;
+        sprite->y = gSprites[gObjectEvents[objectEventId].spriteId].y;
+        UpdateObjectEventSpriteInvisibility(sprite, FALSE);
     }
 }
 
@@ -711,7 +746,7 @@ u32 FldEff_FeetInFlowingWater(void)
         sprite->data[2] = gFieldEffectArguments[2];
         sprite->data[3] = -1;
         sprite->data[4] = -1;
-        sprite->pos2.y = (graphicsInfo->height >> 1) - 4;
+        sprite->y2 = (graphicsInfo->height >> 1) - 4;
         StartSpriteAnim(sprite, 1);
     }
     return 0;
@@ -731,10 +766,10 @@ static void UpdateFeetInFlowingWaterFieldEffect(struct Sprite *sprite)
     {
         objectEvent = &gObjectEvents[objectEventId];
         linkedSprite = &gSprites[objectEvent->spriteId];
-        sprite->pos1.x = linkedSprite->pos1.x;
-        sprite->pos1.y = linkedSprite->pos1.y;
+        sprite->x = linkedSprite->x;
+        sprite->y = linkedSprite->y;
         sprite->subpriority = linkedSprite->subpriority;
-        UpdateObjectEventSpriteVisibility(sprite, FALSE);
+        UpdateObjectEventSpriteInvisibility(sprite, FALSE);
         if (objectEvent->currentCoords.x != sprite->data[3] || objectEvent->currentCoords.y != sprite->data[4])
         {
             sprite->data[3] = objectEvent->currentCoords.x;
@@ -781,8 +816,8 @@ u32 FldEff_HotSpringsWater(void)
         sprite->data[0] = gFieldEffectArguments[0];
         sprite->data[1] = gFieldEffectArguments[1];
         sprite->data[2] = gFieldEffectArguments[2];
-        sprite->data[3] = gSprites[objectEvent->spriteId].pos1.x;
-        sprite->data[4] = gSprites[objectEvent->spriteId].pos1.y;
+        sprite->data[3] = gSprites[objectEvent->spriteId].x;
+        sprite->data[4] = gSprites[objectEvent->spriteId].y;
     }
     return 0;
 }
@@ -801,10 +836,10 @@ void UpdateHotSpringsWaterFieldEffect(struct Sprite *sprite)
     {
         graphicsInfo = GetObjectEventGraphicsInfo(gObjectEvents[objectEventId].graphicsId);
         linkedSprite = &gSprites[gObjectEvents[objectEventId].spriteId];
-        sprite->pos1.x = linkedSprite->pos1.x;
-        sprite->pos1.y = (graphicsInfo->height >> 1) + linkedSprite->pos1.y - 8;
+        sprite->x = linkedSprite->x;
+        sprite->y = (graphicsInfo->height >> 1) + linkedSprite->y - 8;
         sprite->subpriority = linkedSprite->subpriority - 1;
-        UpdateObjectEventSpriteVisibility(sprite, FALSE);
+        UpdateObjectEventSpriteInvisibility(sprite, FALSE);
     }
 }
 
@@ -876,14 +911,21 @@ u32 FldEff_WaterSurfacing(void)
     return 0;
 }
 
-void StartAshFieldEffect(s16 x, s16 y, u16 metatileId, s16 d)
+// Sprite data for FLDEFF_ASH
+#define sState      data[0]
+#define sX          data[1]
+#define sY          data[2]
+#define sMetatileId data[3]
+#define sDelay      data[4]
+
+void StartAshFieldEffect(s16 x, s16 y, u16 metatileId, s16 delay)
 {
     gFieldEffectArguments[0] = x;
     gFieldEffectArguments[1] = y;
-    gFieldEffectArguments[2] = 0x52;
-    gFieldEffectArguments[3] = 1;
+    gFieldEffectArguments[2] = 82; // subpriority
+    gFieldEffectArguments[3] = 1; // priority
     gFieldEffectArguments[4] = metatileId;
-    gFieldEffectArguments[5] = d;
+    gFieldEffectArguments[5] = delay;
     FieldEffectStart(FLDEFF_ASH);
 }
 
@@ -903,50 +945,62 @@ u32 FldEff_Ash(void)
         sprite = &gSprites[spriteId];
         sprite->coordOffsetEnabled = TRUE;
         sprite->oam.priority = gFieldEffectArguments[3];
-        sprite->data[1] = gFieldEffectArguments[0];
-        sprite->data[2] = gFieldEffectArguments[1];
-        sprite->data[3] = gFieldEffectArguments[4];
-        sprite->data[4] = gFieldEffectArguments[5];
+        sprite->sX = gFieldEffectArguments[0];
+        sprite->sY = gFieldEffectArguments[1];
+        sprite->sMetatileId = gFieldEffectArguments[4];
+        sprite->sDelay = gFieldEffectArguments[5];
     }
     return 0;
 }
 
 void (*const gAshFieldEffectFuncs[])(struct Sprite *) = {
-    UpdateAshFieldEffect_Step0,
-    UpdateAshFieldEffect_Step1,
-    UpdateAshFieldEffect_Step2
+    UpdateAshFieldEffect_Wait,
+    UpdateAshFieldEffect_Show,
+    UpdateAshFieldEffect_End
 };
 
 void UpdateAshFieldEffect(struct Sprite *sprite)
 {
-    gAshFieldEffectFuncs[sprite->data[0]](sprite);
+    gAshFieldEffectFuncs[sprite->sState](sprite);
 }
 
-static void UpdateAshFieldEffect_Step0(struct Sprite *sprite)
+static void UpdateAshFieldEffect_Wait(struct Sprite *sprite)
 {
     sprite->invisible = TRUE;
     sprite->animPaused = TRUE;
-    if (--sprite->data[4] == 0)
-        sprite->data[0] = 1;
+    if (--sprite->sDelay == 0)
+        sprite->sState = 1;
 }
 
-static void UpdateAshFieldEffect_Step1(struct Sprite *sprite)
+static void UpdateAshFieldEffect_Show(struct Sprite *sprite)
 {
     sprite->invisible = FALSE;
     sprite->animPaused = FALSE;
-    MapGridSetMetatileIdAt(sprite->data[1], sprite->data[2], sprite->data[3]);
-    CurrentMapDrawMetatileAt(sprite->data[1], sprite->data[2]);
+    MapGridSetMetatileIdAt(sprite->sX, sprite->sY, sprite->sMetatileId);
+    CurrentMapDrawMetatileAt(sprite->sX, sprite->sY);
     gObjectEvents[gPlayerAvatar.objectEventId].triggerGroundEffectsOnMove = TRUE;
-    sprite->data[0] = 2;
+    sprite->sState = 2;
 }
 
-static void UpdateAshFieldEffect_Step2(struct Sprite *sprite)
+static void UpdateAshFieldEffect_End(struct Sprite *sprite)
 {
-    UpdateObjectEventSpriteVisibility(sprite, FALSE);
+    UpdateObjectEventSpriteInvisibility(sprite, FALSE);
     if (sprite->animEnded)
         FieldEffectStop(sprite, FLDEFF_ASH);
 }
 
+#undef sState
+#undef sX
+#undef sY
+#undef sMetatileId
+#undef sDelay
+
+// Sprite data for FLDEFF_SURF_BLOB
+#define tBitfield data[0]
+#define tPlayerOffset data[1]
+#define tPlayerObjId data[2]
+
+
 u32 FldEff_SurfBlob(void)
 {
     u8 spriteId;
@@ -954,12 +1008,12 @@ u32 FldEff_SurfBlob(void)
 
     SetSpritePosToOffsetMapCoords((s16 *)&gFieldEffectArguments[0], (s16 *)&gFieldEffectArguments[1], 8, 8);
     spriteId = CreateSpriteAtEnd(gFieldEffectObjectTemplatePointers[FLDEFFOBJ_SURF_BLOB], gFieldEffectArguments[0], gFieldEffectArguments[1], 0x96);
-    if (spriteId !=MAX_SPRITES)
+    if (spriteId != MAX_SPRITES)
     {
         sprite = &gSprites[spriteId];
         sprite->coordOffsetEnabled = TRUE;
         sprite->oam.paletteNum = 0;
-        sprite->data[2] = gFieldEffectArguments[2];
+        sprite->tPlayerObjId = gFieldEffectArguments[2];
         sprite->data[3] = -1;
         sprite->data[6] = -1;
         sprite->data[7] = -1;
@@ -968,53 +1022,55 @@ u32 FldEff_SurfBlob(void)
     return spriteId;
 }
 
-// States for bobbing up and down while surfing
-void SetSurfBobState(u8 spriteId, u8 value)
+
+void SetSurfBlob_BobState(u8 spriteId, u8 state)
 {
-    gSprites[spriteId].data[0] = (gSprites[spriteId].data[0] & ~0xF) | (value & 0xF);
+    gSprites[spriteId].data[0] = (gSprites[spriteId].data[0] & ~0xF) | (state & 0xF);
 }
 
-void SetSurfBobWhileFlyingOutState(u8 spriteId, u8 value)
+void SetSurfBlob_DontSyncAnim(u8 spriteId, bool8 dontSync)
 {
-    gSprites[spriteId].data[0] = (gSprites[spriteId].data[0] & ~0xF0) | ((value & 0xF) << 4);
+    gSprites[spriteId].data[0] = (gSprites[spriteId].data[0] & ~0xF0) | ((dontSync & 0xF) << 4);
 }
 
-void SetSurfBobWhileFishingState(u8 spriteId, u8 value, s16 data1)
+void SetSurfBlob_PlayerOffset(u8 spriteId, bool8 hasOffset, s16 offset)
 {
-    gSprites[spriteId].data[0] = (gSprites[spriteId].data[0] & ~0xF00) | ((value & 0xF) << 8);
-    gSprites[spriteId].data[1] = data1;
+    gSprites[spriteId].data[0] = (gSprites[spriteId].data[0] & ~0xF00) | ((hasOffset & 0xF) << 8);
+    gSprites[spriteId].tPlayerOffset = offset;
 }
 
-static u8 GetSurfBobState(struct Sprite *sprite)
+static u8 GetSurfBlob_BobState(struct Sprite *sprite)
 {
     return sprite->data[0] & 0xF;
 }
 
-static u8 GetSurfBobWhileFlyingOutState(struct Sprite *sprite)
+// Never TRUE
+static u8 GetSurfBlob_DontSyncAnim(struct Sprite *sprite)
 {
     return (sprite->data[0] & 0xF0) >> 4;
 }
 
-static u8 GetSurfBobWhileFishingState(struct Sprite *sprite)
+static u8 GetSurfBlob_HasPlayerOffset(struct Sprite *sprite)
 {
     return (sprite->data[0] & 0xF00) >> 8;
 }
 
 void UpdateSurfBlobFieldEffect(struct Sprite *sprite)
 {
-    struct ObjectEvent *objectEvent;
-    struct Sprite *linkedSprite;
+    struct ObjectEvent *playerObj;
+    struct Sprite *playerSprite;
 
-    objectEvent = &gObjectEvents[sprite->data[2]];
-    linkedSprite = &gSprites[objectEvent->spriteId];
-    SynchroniseSurfAnim(objectEvent, sprite);
-    sub_81556E8(objectEvent, sprite);
-    CreateBobbingEffect(objectEvent, linkedSprite, sprite);
-    sprite->oam.priority = linkedSprite->oam.priority;
+    playerObj = &gObjectEvents[sprite->tPlayerObjId];
+    playerSprite = &gSprites[playerObj->spriteId];
+    SynchroniseSurfAnim(playerObj, sprite);
+    SynchroniseSurfPosition(playerObj, sprite);
+    UpdateBobbingEffect(playerObj, playerSprite, sprite);
+    sprite->oam.priority = playerSprite->oam.priority;
 }
 
-static void SynchroniseSurfAnim(struct ObjectEvent *objectEvent, struct Sprite *sprite)
+static void SynchroniseSurfAnim(struct ObjectEvent *playerObj, struct Sprite *sprite)
 {
+    // Indexes into sAnimTable_SurfBlob
     u8 surfBlobDirectionAnims[] = {
         [DIR_NONE] = 0,
         [DIR_SOUTH] = 0,
@@ -1027,16 +1083,16 @@ static void SynchroniseSurfAnim(struct ObjectEvent *objectEvent, struct Sprite *
         [DIR_NORTHEAST] = 1,
     };
 
-    if (GetSurfBobWhileFlyingOutState(sprite) == 0)
-        StartSpriteAnimIfDifferent(sprite, surfBlobDirectionAnims[objectEvent->movementDirection]);
+    if (!GetSurfBlob_DontSyncAnim(sprite))
+        StartSpriteAnimIfDifferent(sprite, surfBlobDirectionAnims[playerObj->movementDirection]);
 }
 
-void sub_81556E8(struct ObjectEvent *objectEvent, struct Sprite *sprite)
+void SynchroniseSurfPosition(struct ObjectEvent *playerObj, struct Sprite *sprite)
 {
     u8 i;
-    s16 x = objectEvent->currentCoords.x;
-    s16 y = objectEvent->currentCoords.y;
-    s32 spriteY = sprite->pos2.y;
+    s16 x = playerObj->currentCoords.x;
+    s16 y = playerObj->currentCoords.y;
+    s32 spriteY = sprite->y2;
 
     if (spriteY == 0 && (x != sprite->data[6] || y != sprite->data[7]))
     {
@@ -1048,68 +1104,81 @@ void sub_81556E8(struct ObjectEvent *objectEvent, struct Sprite *sprite)
             MoveCoords(i, &x, &y);
             if (MapGridGetZCoordAt(x, y) == 3)
             {
-                sprite->data[5] ++;
+                sprite->data[5]++;
                 break;
             }
         }
     }
 }
 
-static void CreateBobbingEffect(struct ObjectEvent *objectEvent, struct Sprite *linkedSprite, struct Sprite *sprite)
+static void UpdateBobbingEffect(struct ObjectEvent *playerObj, struct Sprite *playerSprite, struct Sprite *sprite)
 {
-    u16 unk_085CDC6A[] = {3, 7};
-    u8 bobState = GetSurfBobState(sprite);
-    if (bobState != 0)
+    u16 intervals[] = {3, 7};
+    u8 bobState = GetSurfBlob_BobState(sprite);
+    if (bobState != BOB_NONE)
     {
-        if (((u16)(++ sprite->data[4]) & unk_085CDC6A[sprite->data[5]]) == 0)
+        // Update bobbing position of surf blob
+        if (((u16)(++sprite->data[4]) & intervals[sprite->data[5]]) == 0)
         {
-            sprite->pos2.y += sprite->data[3];
+            sprite->y2 += sprite->data[3];
         }
-        if ((sprite->data[4] & 0x0F) == 0)
+        if ((sprite->data[4] & 15) == 0)
         {
             sprite->data[3] = -sprite->data[3];
         }
-        if (bobState != 2)
+        if (bobState != BOB_JUST_MON)
         {
-            if (GetSurfBobWhileFishingState(sprite) == 0)
-                linkedSprite->pos2.y = sprite->pos2.y;
+            // Update bobbing position of player
+            if (!GetSurfBlob_HasPlayerOffset(sprite))
+                playerSprite->y2 = sprite->y2;
             else
-                linkedSprite->pos2.y = sprite->data[1] + sprite->pos2.y;
-            sprite->pos1.x = linkedSprite->pos1.x;
-            sprite->pos1.y = linkedSprite->pos1.y + 8;
+                playerSprite->y2 = sprite->tPlayerOffset + sprite->y2;
+            sprite->x = playerSprite->x;
+            sprite->y = playerSprite->y + 8;
         }
     }
 }
 
-u8 sub_8155800(u8 oldSpriteId)
+#define sSpriteId data[0]
+#define sBobY     data[1]
+#define sTimer    data[2]
+
+u8 StartUnderwaterSurfBlobBobbing(u8 blobSpriteId)
 {
     u8 spriteId;
     struct Sprite *sprite;
 
+    // Create a dummy sprite with its own callback
+    // that tracks the actual surf blob sprite and
+    // makes it bob up and down underwater
     spriteId = CreateSpriteAtEnd(&gDummySpriteTemplate, 0, 0, -1);
     sprite = &gSprites[spriteId];
-    sprite->callback = sub_8155850;
+    sprite->callback = SpriteCB_UnderwaterSurfBlob;
     sprite->invisible = TRUE;
-    sprite->data[0] = oldSpriteId;
-    sprite->data[1] = 1;
+    sprite->sSpriteId = blobSpriteId;
+    sprite->sBobY = 1;
     return spriteId;
 }
 
-static void sub_8155850(struct Sprite *sprite)
+static void SpriteCB_UnderwaterSurfBlob(struct Sprite *sprite)
 {
-    struct Sprite *oldSprite;
+    struct Sprite *blobSprite;
 
-    oldSprite = &gSprites[sprite->data[0]];
-    if (((sprite->data[2]++) & 0x03) == 0)
+    blobSprite = &gSprites[sprite->sSpriteId];
+    if (((sprite->sTimer++) & 3) == 0)
     {
-        oldSprite->pos2.y += sprite->data[1];
+        blobSprite->y2 += sprite->sBobY;
     }
-    if ((sprite->data[2] & 0x0F) == 0)
+    if ((sprite->sTimer & 15) == 0)
     {
-        sprite->data[1] = -sprite->data[1];
+        sprite->sBobY = -sprite->sBobY;
     }
 }
 
+#undef sSpriteId
+#undef sBobY
+#undef sTimer
+
 u32 FldEff_Dust(void)
 {
     u8 spriteId;
@@ -1148,9 +1217,9 @@ u32 FldEff_SandPile(void)
         sprite->data[0] = gFieldEffectArguments[0];
         sprite->data[1] = gFieldEffectArguments[1];
         sprite->data[2] = gFieldEffectArguments[2];
-        sprite->data[3] = gSprites[objectEvent->spriteId].pos1.x;
-        sprite->data[4] = gSprites[objectEvent->spriteId].pos1.y;
-        sprite->pos2.y = (graphicsInfo->height >> 1) - 2;
+        sprite->data[3] = gSprites[objectEvent->spriteId].x;
+        sprite->data[4] = gSprites[objectEvent->spriteId].y;
+        sprite->y2 = (graphicsInfo->height >> 1) - 2;
         SeekSpriteAnim(sprite, 2);
     }
     return 0;
@@ -1168,8 +1237,8 @@ void UpdateSandPileFieldEffect(struct Sprite *sprite)
     }
     else
     {
-        y = gSprites[gObjectEvents[objectEventId].spriteId].pos1.y;
-        x = gSprites[gObjectEvents[objectEventId].spriteId].pos1.x;
+        y = gSprites[gObjectEvents[objectEventId].spriteId].y;
+        x = gSprites[gObjectEvents[objectEventId].spriteId].x;
         if (x != sprite->data[3] || y != sprite->data[4])
         {
             sprite->data[3] = x;
@@ -1179,10 +1248,10 @@ void UpdateSandPileFieldEffect(struct Sprite *sprite)
                 StartSpriteAnim(sprite, 0);
             }
         }
-        sprite->pos1.x = x;
-        sprite->pos1.y = y;
+        sprite->x = x;
+        sprite->y = y;
         sprite->subpriority = gSprites[gObjectEvents[objectEventId].spriteId].subpriority;
-        UpdateObjectEventSpriteVisibility(sprite, FALSE);
+        UpdateObjectEventSpriteInvisibility(sprite, FALSE);
     }
 }
 
@@ -1206,8 +1275,8 @@ void UpdateBubblesFieldEffect(struct Sprite *sprite)
 {
     sprite->data[0] += 0x80;
     sprite->data[0] &= 0x100;
-    sprite->pos1.y -= sprite->data[0] >> 8;
-    UpdateObjectEventSpriteVisibility(sprite, FALSE);
+    sprite->y -= sprite->data[0] >> 8;
+    UpdateObjectEventSpriteInvisibility(sprite, FALSE);
     if (sprite->invisible || sprite->animEnded)
     {
         FieldEffectStop(sprite, FLDEFF_BUBBLES);
@@ -1232,6 +1301,13 @@ u32 FldEff_BerryTreeGrowthSparkle(void)
     return 0;
 }
 
+// Sprite data for FLDEFF_TREE_DISGUISE / FLDEFF_MOUNTAIN_DISGUISE / FLDEFF_SAND_DISGUISE
+#define sState      data[0]
+#define sLocalId    data[2]
+#define sMapNum     data[3]
+#define sMapGroup   data[4]
+#define sReadyToEnd data[7]
+
 u32 ShowTreeDisguiseFieldEffect(void)
 {
     return ShowDisguiseFieldEffect(FLDEFF_TREE_DISGUISE, FLDEFFOBJ_TREE_DISGUISE, 4);
@@ -1263,10 +1339,10 @@ static u32 ShowDisguiseFieldEffect(u8 fldEff, u8 fldEffObj, u8 paletteNum)
         sprite = &gSprites[spriteId];
         sprite->coordOffsetEnabled ++;
         sprite->oam.paletteNum = paletteNum;
-        sprite->data[1] = fldEff;
-        sprite->data[2] = gFieldEffectArguments[0];
-        sprite->data[3] = gFieldEffectArguments[1];
-        sprite->data[4] = gFieldEffectArguments[2];
+        sprite->sFldEff = fldEff;
+        sprite->sLocalId = gFieldEffectArguments[0];
+        sprite->sMapNum = gFieldEffectArguments[1];
+        sprite->sMapGroup = gFieldEffectArguments[2];
     }
     return spriteId;
 }
@@ -1277,62 +1353,65 @@ void UpdateDisguiseFieldEffect(struct Sprite *sprite)
     const struct ObjectEventGraphicsInfo *graphicsInfo;
     struct Sprite *linkedSprite;
 
-    if (TryGetObjectEventIdByLocalIdAndMap(sprite->data[2], sprite->data[3], sprite->data[4], &objectEventId))
-    {
-        FieldEffectStop(sprite, sprite->data[1]);
-    }
+    if (TryGetObjectEventIdByLocalIdAndMap(sprite->sLocalId, sprite->sMapNum, sprite->sMapGroup, &objectEventId))
+        FieldEffectStop(sprite, sprite->sFldEff);
 
     graphicsInfo = GetObjectEventGraphicsInfo(gObjectEvents[objectEventId].graphicsId);
     linkedSprite = &gSprites[gObjectEvents[objectEventId].spriteId];
     sprite->invisible = linkedSprite->invisible;
-    sprite->pos1.x = linkedSprite->pos1.x;
-    sprite->pos1.y = (graphicsInfo->height >> 1) + linkedSprite->pos1.y - 16;
+    sprite->x = linkedSprite->x;
+    sprite->y = (graphicsInfo->height >> 1) + linkedSprite->y - 16;
     sprite->subpriority = linkedSprite->subpriority - 1;
-    if (sprite->data[0] == 1)
+
+    if (sprite->sState == 1)
     {
-        sprite->data[0] ++;
+        sprite->sState++;
         StartSpriteAnim(sprite, 1);
     }
-    if (sprite->data[0] == 2 && sprite->animEnded)
-    {
-        sprite->data[7] = 1;
-    }
-    if (sprite->data[0] == 3)
-    {
-        FieldEffectStop(sprite, sprite->data[1]);
-    }
+
+    if (sprite->sState == 2 && sprite->animEnded)
+        sprite->sReadyToEnd = TRUE;
+
+    if (sprite->sState == 3)
+        FieldEffectStop(sprite, sprite->sFldEff);
 }
 
-void sub_8155D78(struct ObjectEvent *objectEvent)
+void StartRevealDisguise(struct ObjectEvent *objectEvent)
 {
     if (objectEvent->directionSequenceIndex == 1)
-    {
-        gSprites[objectEvent->fieldEffectSpriteId].data[0]++;
-    }
+        gSprites[objectEvent->fieldEffectSpriteId].sState++;
 }
 
-bool8 sub_8155DA0(struct ObjectEvent *objectEvent)
+bool8 UpdateRevealDisguise(struct ObjectEvent *objectEvent)
 {
     struct Sprite *sprite;
 
     if (objectEvent->directionSequenceIndex == 2)
-    {
         return TRUE;
-    }
+
     if (objectEvent->directionSequenceIndex == 0)
-    {
         return TRUE;
-    }
+
     sprite = &gSprites[objectEvent->fieldEffectSpriteId];
-    if (sprite->data[7])
+    if (sprite->sReadyToEnd)
     {
         objectEvent->directionSequenceIndex = 2;
-        sprite->data[0]++;
+        sprite->sState++;
         return TRUE;
     }
     return FALSE;
 }
 
+#undef sState
+#undef sLocalId
+#undef sMapNum
+#undef sMapGroup
+#undef sReadyToEnd
+
+// Sprite data for FLDEFF_SPARKLE
+#define sFinished data[0]
+#define sEndTimer data[1]
+
 u32 FldEff_Sparkle(void)
 {
     u8 spriteId;
@@ -1351,22 +1430,22 @@ u32 FldEff_Sparkle(void)
 
 void UpdateSparkleFieldEffect(struct Sprite *sprite)
 {
-    if (sprite->data[0] == 0)
+    if (!sprite->sFinished)
     {
         if (sprite->animEnded)
         {
             sprite->invisible = TRUE;
-            sprite->data[0]++;
+            sprite->sFinished++;
         }
-
-        if (sprite->data[0] == 0)
-            return;
     }
 
-    if (++sprite->data[1] > 34)
+    if (sprite->sFinished && ++sprite->sEndTimer > 34)
         FieldEffectStop(sprite, FLDEFF_SPARKLE);
 }
 
+#undef sFinished
+#undef sEndTimer
+
 #define sTimer       data[0]
 #define sState       data[2]
 #define sStartY      data[4]
@@ -1389,25 +1468,25 @@ static bool8 AnimateRayquazaInFigure8(struct Sprite *sprite)
     switch (sprite->sAnimState)
     {
     case 0:
-        sprite->pos2.x += GetFigure8XOffset(sprite->sAnimCounter);
-        sprite->pos2.y += GetFigure8YOffset(sprite->sAnimCounter);
+        sprite->x2 += GetFigure8XOffset(sprite->sAnimCounter);
+        sprite->y2 += GetFigure8YOffset(sprite->sAnimCounter);
         break;
     case 1:
-        sprite->pos2.x -= GetFigure8XOffset((FIGURE_8_LENGTH - 1) - sprite->sAnimCounter);
-        sprite->pos2.y += GetFigure8YOffset((FIGURE_8_LENGTH - 1) - sprite->sAnimCounter);
+        sprite->x2 -= GetFigure8XOffset((FIGURE_8_LENGTH - 1) - sprite->sAnimCounter);
+        sprite->y2 += GetFigure8YOffset((FIGURE_8_LENGTH - 1) - sprite->sAnimCounter);
         break;
     case 2:
-        sprite->pos2.x -= GetFigure8XOffset(sprite->sAnimCounter);
-        sprite->pos2.y += GetFigure8YOffset(sprite->sAnimCounter);
+        sprite->x2 -= GetFigure8XOffset(sprite->sAnimCounter);
+        sprite->y2 += GetFigure8YOffset(sprite->sAnimCounter);
         break;
     case 3:
-        sprite->pos2.x += GetFigure8XOffset((FIGURE_8_LENGTH - 1) - sprite->sAnimCounter);
-        sprite->pos2.y += GetFigure8YOffset((FIGURE_8_LENGTH - 1) - sprite->sAnimCounter);
+        sprite->x2 += GetFigure8XOffset((FIGURE_8_LENGTH - 1) - sprite->sAnimCounter);
+        sprite->y2 += GetFigure8YOffset((FIGURE_8_LENGTH - 1) - sprite->sAnimCounter);
         break;
     }
 
     // Update spotlight to sweep left and right with Rayquaza
-    SetGpuReg(REG_OFFSET_BG0HOFS, -sprite->pos2.x);
+    SetGpuReg(REG_OFFSET_BG0HOFS, -sprite->x2);
 
     if (++sprite->sAnimCounter == FIGURE_8_LENGTH)
     {
@@ -1416,8 +1495,8 @@ static bool8 AnimateRayquazaInFigure8(struct Sprite *sprite)
     }
     if (sprite->sAnimState == 4)
     {
-        sprite->pos2.y = 0;
-        sprite->pos2.x = 0;
+        sprite->y2 = 0;
+        sprite->x2 = 0;
         finished = TRUE;
     }
 
@@ -1449,7 +1528,7 @@ void UpdateRayquazaSpotlightEffect(struct Sprite *sprite)
             }
             break;
         case 1:
-            sprite->pos1.y = (gSineTable[sprite->sTimer / 3] >> 2) + sprite->sStartY;
+            sprite->y = (gSineTable[sprite->sTimer / 3] >> 2) + sprite->sStartY;
             if (sprite->sTimer == 189)
             {
                 sprite->sState = 2;
@@ -1470,7 +1549,7 @@ void UpdateRayquazaSpotlightEffect(struct Sprite *sprite)
             }
             break;
         case 3:
-            if (sprite->pos2.y == 0)
+            if (sprite->y2 == 0)
             {
                 sprite->sTimer = 0;
                 sprite->sState++;
@@ -1478,10 +1557,10 @@ void UpdateRayquazaSpotlightEffect(struct Sprite *sprite)
             if (sprite->sTimer == 5)
             {
                 sprite->sTimer = 0;
-                if (sprite->pos2.y > 0)
-                    sprite->pos2.y--;
+                if (sprite->y2 > 0)
+                    sprite->y2--;
                 else
-                    sprite->pos2.y++;
+                    sprite->y2++;
             }
             break;
         case 4:
@@ -1535,7 +1614,7 @@ void UpdateRayquazaSpotlightEffect(struct Sprite *sprite)
     if (sprite->sState == 1)
     {
         if ((sprite->data[1] & 7) == 0)
-            sprite->pos2.y += sprite->data[3];
+            sprite->y2 += sprite->data[3];
         if ((sprite->data[1] & 15) == 0)
             sprite->data[3] = -sprite->data[3];
         sprite->data[1]++;
@@ -1551,16 +1630,17 @@ void UpdateRayquazaSpotlightEffect(struct Sprite *sprite)
 #undef sAnimCounter
 #undef sAnimState
 
+// Used by FLDEFF_JUMP_TALL_GRASS and FLDEFF_JUMP_LONG_GRASS
 void UpdateJumpImpactEffect(struct Sprite *sprite)
 {
     if (sprite->animEnded)
     {
-        FieldEffectStop(sprite, sprite->data[1]);
+        FieldEffectStop(sprite, sprite->sFldEff);
     }
     else
     {
-        UpdateObjectEventSpriteVisibility(sprite, FALSE);
-        SetObjectSubpriorityByZCoord(sprite->data[0], sprite, 0);
+        UpdateObjectEventSpriteInvisibility(sprite, FALSE);
+        SetObjectSubpriorityByZCoord(sprite->sElevation, sprite, 0);
     }
 }
 
@@ -1569,10 +1649,10 @@ void WaitFieldEffectSpriteAnim(struct Sprite *sprite)
     if (sprite->animEnded)
         FieldEffectStop(sprite, sprite->data[0]);
     else
-        UpdateObjectEventSpriteVisibility(sprite, FALSE);
+        UpdateObjectEventSpriteInvisibility(sprite, FALSE);
 }
 
-static void sub_81561FC(struct Sprite *sprite, u8 z, u8 offset)
+static void UpdateGrassFieldEffectSubpriority(struct Sprite *sprite, u8 z, u8 offset)
 {
     u8 i;
     s16 var, xhi, lyhi, yhi, ylo;
@@ -1587,13 +1667,13 @@ static void sub_81561FC(struct Sprite *sprite, u8 z, u8 offset)
         {
             graphicsInfo = GetObjectEventGraphicsInfo(objectEvent->graphicsId);
             linkedSprite = &gSprites[objectEvent->spriteId];
-            xhi = sprite->pos1.x + sprite->centerToCornerVecX;
-            var = sprite->pos1.x - sprite->centerToCornerVecX;
-            if (xhi < linkedSprite->pos1.x && var > linkedSprite->pos1.x)
+            xhi = sprite->x + sprite->centerToCornerVecX;
+            var = sprite->x - sprite->centerToCornerVecX;
+            if (xhi < linkedSprite->x && var > linkedSprite->x)
             {
-                lyhi = linkedSprite->pos1.y + linkedSprite->centerToCornerVecY;
-                var = linkedSprite->pos1.y;
-                ylo = sprite->pos1.y - sprite->centerToCornerVecY;
+                lyhi = linkedSprite->y + linkedSprite->centerToCornerVecY;
+                var = linkedSprite->y;
+                ylo = sprite->y - sprite->centerToCornerVecY;
                 yhi = ylo + linkedSprite->centerToCornerVecY;
                 if ((lyhi < yhi || lyhi < ylo) && var > yhi && sprite->subpriority <= linkedSprite->subpriority)
                 {
@@ -1605,18 +1685,27 @@ static void sub_81561FC(struct Sprite *sprite, u8 z, u8 offset)
     }
 }
 
-// Unused data. Feel free to remove.
-static const u8 gUnknown_085CDC6E[] =
-{
-    0x01, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x01, 0x02, 0x02,
-    0x01, 0x02, 0x02, 0x01, 0x02, 0x02, 0x01, 0x02, 0x01, 0x01, 0x02, 0x01, 0x01, 0x02,
-    0x01, 0x01, 0x02, 0x01, 0x01, 0x02, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
-    0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x01, 0x01, 0x01, 0x00, 0x01, 0x01, 0x00,
-    0x01, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00,
-    0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x01, 0x00, 0x00, 0x01, 0x00, 0x01, 0x01,
-    0x00, 0x01, 0x01, 0x00, 0x01, 0x01, 0x00, 0x01, 0x01, 0x00, 0x01, 0x01, 0x00, 0x00,
-    0x01, 0x00, 0x00, 0x01, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0x00, 0x00, 0xFF,
-    0x00, 0x00, 0xFF, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0xFF, 0xFF, 0xFF,
-    0xFF, 0xFF, 0xFF, 0xFE, 0x00, 0x00
+// Unused, duplicates of data in event_object_movement.c
+static const s8 sFigure8XOffsets[FIGURE_8_LENGTH] = {
+    1, 2, 2, 2, 2, 2, 2, 2,
+    2, 2, 2, 1, 2, 2, 1, 2,
+    2, 1, 2, 2, 1, 2, 1, 1,
+    2, 1, 1, 2, 1, 1, 2, 1,
+    1, 2, 1, 1, 1, 1, 1, 1,
+    1, 1, 1, 1, 1, 1, 1, 1,
+    0, 1, 1, 1, 0, 1, 1, 0,
+    1, 0, 1, 0, 1, 0, 0, 0,
+    0, 1, 0, 0, 0, 0, 0, 0,
+};
+
+static const s8 sFigure8YOffsets[FIGURE_8_LENGTH] = {
+     0,  0,  1,  0,  0,  1,  0,  0,
+     1,  0,  1,  1,  0,  1,  1,  0,
+     1,  1,  0,  1,  1,  0,  1,  1,
+     0,  0,  1,  0,  0,  1,  0,  0,
+     1,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0, -1,  0,  0, -1,  0,  0,
+    -1,  0, -1, -1,  0, -1, -1,  0,
+    -1, -1, -1, -1, -1, -1, -1, -2,
 };