Clean up mirage tower

4 files changed, 211 insertions, 184 deletions

diff --git a/data/maps/Route111/scripts.inc b/data/maps/Route111/scripts.inc
index 322c9a2b7..9e6e4c8eb 100644
--- a/data/maps/Route111/scripts.inc
+++ b/data/maps/Route111/scripts.inc
@@ -2,9 +2,10 @@
 .set LOCALID_VICTORIA, 2
 .set LOCALID_VIVI, 3
 .set LOCALID_VICKY, 4
-.set LOCALID_PLAYER_FALLING, 45
 .set LOCALID_ROCK_SMASH_MAN, 46
 
+@ Note: LOCALID_ROUTE111_PLAYER_FALLING is used in mirage_tower.c, and is defined in event_objects.h
+
 Route111_MapScripts:: @ 81F0CA7
 	map_script MAP_SCRIPT_ON_LOAD, Route111_OnLoad
 	map_script MAP_SCRIPT_ON_TRANSITION, Route111_OnTransition
@@ -127,11 +128,11 @@ Route111_EventScript_MirageTowerDisappear:: @ 81F0E60
 	waitstate
 	delay 24
 	playse SE_FALL
-	addobject LOCALID_PLAYER_FALLING
+	addobject LOCALID_ROUTE111_PLAYER_FALLING
 	special StartPlayerDescendMirageTower
 	waitstate
 	showobjectat OBJ_EVENT_ID_PLAYER, MAP_LITTLEROOT_TOWN
-	removeobject LOCALID_PLAYER_FALLING
+	removeobject LOCALID_ROUTE111_PLAYER_FALLING
 	delay 16
 	turnobject OBJ_EVENT_ID_PLAYER, DIR_NORTH
 	delay 16
diff --git a/graphics/misc/fossil.png b/graphics/misc/fossil.png
deleted file mode 100644
index f92649e98..000000000
--- a/graphics/misc/fossil.png
+++ /dev/null
diff --git a/include/constants/event_objects.h b/include/constants/event_objects.h
index 7a224940f..357251548 100644
--- a/include/constants/event_objects.h
+++ b/include/constants/event_objects.h
@@ -279,7 +279,11 @@
 
 #define FIRST_DECORATION_SPRITE_GFX OBJ_EVENT_GFX_PICHU_DOLL
 
+// Special object event local ids
 #define OBJ_EVENT_ID_PLAYER 0xFF
 #define OBJ_EVENT_ID_CAMERA 0x7F
 
+// Object event local ids referenced in C files
+#define LOCALID_ROUTE111_PLAYER_FALLING 45
+
 #endif  // GUARD_CONSTANTS_EVENT_OBJECTS_H
diff --git a/src/mirage_tower.c b/src/mirage_tower.c
index d18ddcc0f..9f91dff50 100644
--- a/src/mirage_tower.c
+++ b/src/mirage_tower.c
@@ -14,12 +14,14 @@
 #include "sprite.h"
 #include "task.h"
 #include "window.h"
+#include "constants/event_objects.h"
 #include "constants/maps.h"
 #include "constants/rgb.h"
 #include "constants/songs.h"
 #include "constants/metatile_labels.h"
 
-struct MirageTowerPulseBlend {
+struct MirageTowerPulseBlend 
+{
     u8 taskId;
     struct PulseBlend pulseBlend;
 };
@@ -37,59 +39,51 @@ struct BgRegOffsets
     u16 bgVOFS;
 };
 
-struct Struct203CF10
+struct FallAnim_Tower
 {
-    u8 *buffer;
-    u8 currIndex;
+    u8 *disintegrateRand;
+    u8 disintegrateIdx;
 };
 
-struct DynamicSpriteFrameImage
-{
-    u8 *data;
-    u16 size;
-};
-
-struct Struct203CF0C
+struct FallAnim_Fossil
 {
     u8 *frameImageTiles;
-    struct DynamicSpriteFrameImage *frameImage;
+    struct SpriteFrameImage *frameImage;
     u8 spriteId;
-    u16 *unkC;
-    u16 unk10;
+    u16 *disintegrateRand;
+    u16 disintegrateIdx;
 };
 
+#define TAG_CEILING_CRUMBLE 4000
+
 #define MIRAGE_TOWER_GFX_LENGTH (sizeof(sBlankTile_Gfx) + sizeof(sMirageTower_Gfx))
-#define ROOT_FOSSIL_GFX_LENGTH sizeof(sRootFossil_Gfx)
-#define ROOT_FOSSIL_GFX_RANDOMIZER_LENGTH 0x100
+#define FOSSIL_DISINTEGRATE_LENGTH 0x100
 
-// extern data
-extern const struct SpriteSheet gMirageTowerCeilingCrumbleSpriteSheets[];
-extern const s16 sCeilingCrumblePositions[][3];
+static const struct SpriteSheet sCeilingCrumbleSpriteSheets[];
+static const s16 sCeilingCrumblePositions[][3];
 
-// static functions
-static void PlayerDescendMirageTower(u8 taskId);
-static void DoScreenShake(u8 taskId);
+static void PlayerDescendMirageTower(u8);
+static void DoScreenShake(u8);
 static void IncrementCeilingCrumbleFinishedCount(void);
-static void WaitCeilingCrumble(u8 taskId);
-static void FinishCeilingCrumbleTask(u8 taskId);
+static void WaitCeilingCrumble(u8);
+static void FinishCeilingCrumbleTask(u8);
 static void CreateCeilingCrumbleSprites(void);
-static void MoveCeilingCrumbleSprite(struct Sprite* sprite);
-static void DoMirageTowerDisintegration(u8 taskId);
-static void InitMirageTowerShake(u8 taskId);
-static void DoFossilFallAndSink(u8 taskId);
-static void sub_81BF248(struct Sprite *);
-static void sub_81BF2B8(u8* a, u16 b, u8 c, u8 d, u8 e);
-
-// rodata
+static void SpriteCB_CeilingCrumble(struct Sprite*);
+static void DoMirageTowerDisintegration(u8);
+static void InitMirageTowerShake(u8);
+static void Task_FossilFallAndSink(u8);
+static void SpriteCB_FallingFossil(struct Sprite *);
+static void UpdateDisintegrationEffect(u8*, u16, u8, u8, u8);
+
 static const u8 sBlankTile_Gfx[32] = {0};
 static const u8 sMirageTower_Gfx[] = INCBIN_U8("graphics/misc/mirage_tower.4bpp");
 static const u16 sMirageTowerTilemap[] = INCBIN_U16("graphics/misc/mirage_tower.bin");
-static const u16 sRootFossil_Pal[] = INCBIN_U16("graphics/misc/fossil.gbapal");
-static const u8 sRootFossil_Gfx[] = INCBIN_U8("graphics/misc/fossil.4bpp");
+static const u16 sFossil_Pal[] = INCBIN_U16("graphics/object_events/pics/misc/fossil.gbapal"); // Unused
+static const u8 sFossil_Gfx[] = INCBIN_U8("graphics/object_events/pics/misc/fossil.4bpp"); // Duplicate of gObjectEventPic_Fossil
 static const u8 sMirageTowerCrumbles_Gfx[] = INCBIN_U8("graphics/misc/mirage_tower_crumbles.4bpp");
 static const u16 sMirageTowerCrumbles_Palette[] = INCBIN_U16("graphics/misc/mirage_tower_crumbles.gbapal");
 
-const s16 sCeilingCrumblePositions[][3] =
+static const s16 sCeilingCrumblePositions[][3] =
 {
     {  0,  10,  65},
     { 17,   3,  50},
@@ -101,10 +95,10 @@ const s16 sCeilingCrumblePositions[][3] =
     {-24,  -4,  65},
 };
 
-const struct SpriteSheet gMirageTowerCeilingCrumbleSpriteSheets[] =
+static const struct SpriteSheet sCeilingCrumbleSpriteSheets[] =
 {
-    {sMirageTowerCrumbles_Gfx, 0x0080, 4000},
-    {NULL}
+    {sMirageTowerCrumbles_Gfx, 0x80, TAG_CEILING_CRUMBLE},
+    {}
 };
 
 static const struct MetatileCoords sInvisibleMirageTowerMetatiles[] =
@@ -129,13 +123,13 @@ static const struct MetatileCoords sInvisibleMirageTowerMetatiles[] =
     {20, 58, METATILE_General_SandPit_Center},
 };
 
-static const union AnimCmd gSpriteAnim_8617DEC[] =
+static const union AnimCmd sAnim_FallingFossil[] =
 {
     ANIMCMD_FRAME(0, 1),
     ANIMCMD_END,
 };
 
-static const struct OamData gOamData_8617DF4 =
+static const struct OamData sOamData_FallingFossil =
 {
     .y = 0,
     .affineMode = ST_OAM_AFFINE_OFF,
@@ -152,14 +146,20 @@ static const struct OamData gOamData_8617DF4 =
     .affineParam = 0,
 };
 
-static const union AnimCmd *const gSpriteAnimTable_8617DFC[] =
+static const union AnimCmd *const sAnims_FallingFossil[] =
 {
-    gSpriteAnim_8617DEC,
+    sAnim_FallingFossil,
 };
 
-static const struct SpriteTemplate gUnknown_08617E00 =
+static const struct SpriteTemplate sSpriteTemplate_FallingFossil =
 {
-    0xFFFF, 0xFFFF, &gOamData_8617DF4, gSpriteAnimTable_8617DFC, NULL, gDummySpriteAffineAnimTable, SpriteCallbackDummy
+    .tileTag = 0xFFFF,
+    .paletteTag = 0xFFFF,
+    .oam = &sOamData_FallingFossil,
+    .anims = sAnims_FallingFossil,
+    .images = NULL,
+    .affineAnims = gDummySpriteAffineAnimTable,
+    .callback = SpriteCallbackDummy
 };
 
 const struct PulseBlendSettings gMirageTowerPulseBlendSettings = {
@@ -174,18 +174,18 @@ const struct PulseBlendSettings gMirageTowerPulseBlendSettings = {
     .unk7_7 = 1,
 };
 
-static const union AnimCmd sCeilingCrumble2AnimCmd[] =
+static const union AnimCmd sAnim_CeilingCrumbleSmall[] =
 {
     ANIMCMD_FRAME(0, 12),
     ANIMCMD_JUMP(0),
 };
 
-static const union AnimCmd *const sCeilingCrumble2AnimCmds[] =
+static const union AnimCmd *const sAnims_CeilingCrumbleSmall[] =
 {
-    sCeilingCrumble2AnimCmd,
+    sAnim_CeilingCrumbleSmall,
 };
 
-static const struct OamData sCeilingCrumble2OamData =
+static const struct OamData sOamData_CeilingCrumbleSmall =
 {
     .y = 0,
     .affineMode = ST_OAM_AFFINE_OFF,
@@ -202,28 +202,28 @@ static const struct OamData sCeilingCrumble2OamData =
     .affineParam = 0,
 };
 
-static const struct SpriteTemplate sCeilingCrumbleSpriteTemplate2 = {
-    .tileTag = 4000,
+static const struct SpriteTemplate sSpriteTemplate_CeilingCrumbleSmall = {
+    .tileTag = TAG_CEILING_CRUMBLE,
     .paletteTag = 0xFFFF,
-    .oam = &sCeilingCrumble2OamData,
-    .anims = sCeilingCrumble2AnimCmds,
+    .oam = &sOamData_CeilingCrumbleSmall,
+    .anims = sAnims_CeilingCrumbleSmall,
     .images = NULL,
     .affineAnims = gDummySpriteAffineAnimTable,
-    .callback = MoveCeilingCrumbleSprite
+    .callback = SpriteCB_CeilingCrumble
 };
 
-static const union AnimCmd sCeilingCrumble1AnimCmd[] =
+static const union AnimCmd sAnim_CeilingCrumbleLarge[] =
 {
     ANIMCMD_FRAME(0, 12),
     ANIMCMD_JUMP(0),
 };
 
-static const union AnimCmd *const sCeilingCrumble1AnimCmds[] =
+static const union AnimCmd *const sAnims_CeilingCrumbleLarge[] =
 {
-    sCeilingCrumble1AnimCmd,
+    sAnim_CeilingCrumbleLarge,
 };
 
-static const struct OamData sCeilingCrumble1OamData =
+static const struct OamData sOamData_CeilingCrumbleLarge =
 {
     .y = 0,
     .affineMode = ST_OAM_AFFINE_OFF,
@@ -240,24 +240,26 @@ static const struct OamData sCeilingCrumble1OamData =
     .affineParam = 0,
 };
 
-static const struct SpriteTemplate sCeilingCrumbleSpriteTemplate1 = {
-    .tileTag = 4000,
+static const struct SpriteTemplate sSpriteTemplate_CeilingCrumbleLarge = {
+    .tileTag = TAG_CEILING_CRUMBLE,
     .paletteTag = 0xFFFF,
-    .oam = &sCeilingCrumble1OamData,
-    .anims = sCeilingCrumble1AnimCmds,
+    .oam = &sOamData_CeilingCrumbleLarge,
+    .anims = sAnims_CeilingCrumbleLarge,
     .images = NULL,
     .affineAnims = gDummySpriteAffineAnimTable,
-    .callback = MoveCeilingCrumbleSprite
+    .callback = SpriteCB_CeilingCrumble
 };
 
 EWRAM_DATA static u8* sMirageTowerGfxBuffer = NULL;
 EWRAM_DATA static u8* sMirageTowerTilemapBuffer = NULL;
-EWRAM_DATA static struct Struct203CF0C *sUnknown_0203CF0C = NULL;
-EWRAM_DATA static struct Struct203CF10 *sUnknown_0203CF10 = NULL;
+EWRAM_DATA static struct FallAnim_Fossil *sFallingFossil = NULL;
+EWRAM_DATA static struct FallAnim_Tower *sFallingTower = NULL;
 EWRAM_DATA static struct BgRegOffsets *sBgShakeOffsets = NULL;
-EWRAM_DATA struct MirageTowerPulseBlend *sMirageTowerPulseBlend = NULL;
+EWRAM_DATA static struct MirageTowerPulseBlend *sMirageTowerPulseBlend = NULL;
 
-static u16 gUnknown_030012A8[8];
+// Holds data about the disintegration effect for Mirage Tower / the unchosen fossil.
+// Never read, presumably for debugging
+static u16 sDebug_DisintegrationData[8];
 
 bool8 IsMirageTowerVisible(void)
 {
@@ -319,6 +321,7 @@ void SetMirageTowerVisibility(void)
 
     if (VarGet(VAR_MIRAGE_TOWER_STATE))
     {
+        // Mirage Tower event has already been completed, hide it
         FlagClear(FLAG_MIRAGE_TOWER_VISIBLE);
         return;
     }
@@ -343,32 +346,40 @@ void StartPlayerDescendMirageTower(void)
     CreateTask(PlayerDescendMirageTower, 8);
 }
 
+// As the tower disintegrates, a duplicate object event of the player
+// is created at the top of the tower and moved down to show the player falling
 static void PlayerDescendMirageTower(u8 taskId)
 {
     u8 objectEventId;
-    struct ObjectEvent *fakePlayerObjectEvent;
-    struct ObjectEvent *playerObjectEvent;
-
-    TryGetObjectEventIdByLocalIdAndMap(45, gSaveBlock1Ptr->location.mapNum, gSaveBlock1Ptr->location.mapGroup, &objectEventId);
-    fakePlayerObjectEvent = &gObjectEvents[objectEventId];
-    gSprites[fakePlayerObjectEvent->spriteId].pos2.y += 4;
-    playerObjectEvent = &gObjectEvents[gPlayerAvatar.objectEventId];
-    if ((gSprites[fakePlayerObjectEvent->spriteId].pos1.y + gSprites[fakePlayerObjectEvent->spriteId].pos2.y) >=
-        (gSprites[playerObjectEvent->spriteId].pos1.y + gSprites[playerObjectEvent->spriteId].pos2.y))
+    struct ObjectEvent *fallingPlayer;
+    struct ObjectEvent *player;
+
+    TryGetObjectEventIdByLocalIdAndMap(LOCALID_ROUTE111_PLAYER_FALLING, gSaveBlock1Ptr->location.mapNum, gSaveBlock1Ptr->location.mapGroup, &objectEventId);
+    fallingPlayer = &gObjectEvents[objectEventId];
+    gSprites[fallingPlayer->spriteId].pos2.y += 4;
+    player = &gObjectEvents[gPlayerAvatar.objectEventId];
+    if ((gSprites[fallingPlayer->spriteId].pos1.y + gSprites[fallingPlayer->spriteId].pos2.y) >=
+        (gSprites[player->spriteId].pos1.y + gSprites[player->spriteId].pos2.y))
     {
         DestroyTask(taskId);
         EnableBothScriptContexts();
     }
 }
 
+#define tXShakeOffset data[0]
+#define tTimer        data[1]
+#define tNumShakes    data[2]
+#define tShakeDelay   data[3]
+#define tYShakeOffset data[4]
+
 static void StartScreenShake(u8 yShakeOffset, u8 xShakeOffset, u8 numShakes, u8 shakeDelay)
 {
     u8 taskId = CreateTask(DoScreenShake, 9);
-    gTasks[taskId].data[0] = xShakeOffset;
-    gTasks[taskId].data[1] = 0;
-    gTasks[taskId].data[2] = numShakes;
-    gTasks[taskId].data[3] = shakeDelay;
-    gTasks[taskId].data[4] = yShakeOffset;
+    gTasks[taskId].tXShakeOffset = xShakeOffset;
+    gTasks[taskId].tTimer = 0;
+    gTasks[taskId].tNumShakes = numShakes;
+    gTasks[taskId].tShakeDelay = shakeDelay;
+    gTasks[taskId].tYShakeOffset = yShakeOffset;
     SetCameraPanningCallback(NULL);
     PlaySE(SE_M_STRENGTH);
 }
@@ -378,15 +389,15 @@ static void DoScreenShake(u8 taskId)
     s16 *data;
 
     data = gTasks[taskId].data;
-    data[1]++;
-    if (data[1] % data[3] == 0)
+    tTimer++;
+    if (tTimer % tShakeDelay == 0)
     {
-        data[1] = 0;
-        data[2]--;
-        data[0] = -data[0];
-        data[4] = -data[4];
-        SetCameraPanning(data[0], data[4]);
-        if (data[2] == 0)
+        tTimer = 0;
+        tNumShakes--;
+        tXShakeOffset = -tXShakeOffset;
+        tYShakeOffset = -tYShakeOffset;
+        SetCameraPanning(tXShakeOffset, tYShakeOffset);
+        if (tNumShakes == 0)
         {
             IncrementCeilingCrumbleFinishedCount();
             DestroyTask(taskId);
@@ -395,6 +406,12 @@ static void DoScreenShake(u8 taskId)
     }
 }
 
+#undef tXShakeOffset
+#undef tTimer
+#undef tNumShakes
+#undef tShakeDelay
+#undef tYShakeOffset
+
 static void IncrementCeilingCrumbleFinishedCount(void)
 {
     u8 taskId = FindTaskIdByFunc(WaitCeilingCrumble);
@@ -404,7 +421,7 @@ static void IncrementCeilingCrumbleFinishedCount(void)
 
 void DoMirageTowerCeilingCrumble(void)
 {
-    LoadSpriteSheets(gMirageTowerCeilingCrumbleSpriteSheets);
+    LoadSpriteSheets(sCeilingCrumbleSpriteSheets);
     CreateCeilingCrumbleSprites();
     CreateTask(WaitCeilingCrumble, 8);
     StartScreenShake(2, 1, 16, 3);
@@ -421,7 +438,7 @@ static void WaitCeilingCrumble(u8 taskId)
 
 static void FinishCeilingCrumbleTask(u8 taskId)
 {
-    FreeSpriteTilesByTag(4000);
+    FreeSpriteTilesByTag(TAG_CEILING_CRUMBLE);
     DestroyTask(taskId);
     EnableBothScriptContexts();
 }
@@ -433,21 +450,21 @@ static void CreateCeilingCrumbleSprites(void)
 
     for (i = 0; i < 8; i++)
     {
-        spriteId = CreateSprite(&sCeilingCrumbleSpriteTemplate1, sCeilingCrumblePositions[i][0] + 120, sCeilingCrumblePositions[i][1], 8);
+        spriteId = CreateSprite(&sSpriteTemplate_CeilingCrumbleLarge, sCeilingCrumblePositions[i][0] + 120, sCeilingCrumblePositions[i][1], 8);
         gSprites[spriteId].oam.priority = 0;
         gSprites[spriteId].oam.paletteNum = 0;
         gSprites[spriteId].data[0] = i;
     }
     for (i = 0; i < 8; i++)
     {
-        spriteId = CreateSprite(&sCeilingCrumbleSpriteTemplate2, sCeilingCrumblePositions[i][0] + 115, sCeilingCrumblePositions[i][1] - 3, 8);
+        spriteId = CreateSprite(&sSpriteTemplate_CeilingCrumbleSmall, sCeilingCrumblePositions[i][0] + 115, sCeilingCrumblePositions[i][1] - 3, 8);
         gSprites[spriteId].oam.priority = 0;
         gSprites[spriteId].oam.paletteNum = 0;
         gSprites[spriteId].data[0] = i;
     }
 }
 
-static void MoveCeilingCrumbleSprite(struct Sprite* sprite)
+static void SpriteCB_CeilingCrumble(struct Sprite* sprite)
 {
     sprite->data[1] += 2;
     sprite->pos2.y = sprite->data[1] / 2;
@@ -478,7 +495,7 @@ void StartMirageTowerShake(void)
 
 void StartMirageTowerFossilFallAndSink(void)
 {
-    CreateTask(DoFossilFallAndSink, 9);
+    CreateTask(Task_FossilFallAndSink, 9);
 }
 
 static void SetBgShakeOffsets(void)
@@ -501,42 +518,44 @@ static void UpdateBgShake(u8 taskId)
     }
 }
 
+#define tState data[0]
+
 static void InitMirageTowerShake(u8 taskId)
 {
     u8 zero;
 
-    switch (gTasks[taskId].data[0])
+    switch (gTasks[taskId].tState)
     {
     case 0:
         FreeAllWindowBuffers();
         SetBgAttribute(0, BG_ATTR_PRIORITY, 2);
-        gTasks[taskId].data[0]++;
+        gTasks[taskId].tState++;
         break;
     case 1:
         sMirageTowerGfxBuffer = (u8 *)AllocZeroed(MIRAGE_TOWER_GFX_LENGTH);
         sMirageTowerTilemapBuffer = (u8 *)AllocZeroed(BG_SCREEN_SIZE);
         ChangeBgX(0, 0, 0);
         ChangeBgY(0, 0, 0);
-        gTasks[taskId].data[0]++;
+        gTasks[taskId].tState++;
         break;
     case 2:
         CpuSet(sBlankTile_Gfx, sMirageTowerGfxBuffer, MIRAGE_TOWER_GFX_LENGTH / 2);
         LoadBgTiles(0, sMirageTowerGfxBuffer, MIRAGE_TOWER_GFX_LENGTH, 0);
-        gTasks[taskId].data[0]++;
+        gTasks[taskId].tState++;
         break;
     case 3:
         SetBgTilemapBuffer(0, sMirageTowerTilemapBuffer);
         CopyToBgTilemapBufferRect_ChangePalette(0, &sMirageTowerTilemap, 12, 29, 6, 12, 17);
         CopyBgTilemapBufferToVram(0);
-        gTasks[taskId].data[0]++;
+        gTasks[taskId].tState++;
         break;
     case 4:
         ShowBg(0);
-        gTasks[taskId].data[0]++;
+        gTasks[taskId].tState++;
         break;
     case 5:
         SetInvisibleMirageTowerMetatiles();
-        gTasks[taskId].data[0]++;
+        gTasks[taskId].tState++;
         break;
     case 6:
         sBgShakeOffsets = Alloc(sizeof(*sBgShakeOffsets));
@@ -558,27 +577,29 @@ static void DoMirageTowerDisintegration(u8 taskId)
     u16 i;
     u8 index;
 
-    switch (gTasks[taskId].data[0])
+    switch (gTasks[taskId].tState)
     {
     case 1:
-        sUnknown_0203CF10 = AllocZeroed(OUTER_BUFFER_LENGTH * sizeof(struct Struct203CF10));
+        sFallingTower = AllocZeroed(OUTER_BUFFER_LENGTH * sizeof(struct FallAnim_Tower));
         break;
     case 3:
         if (gTasks[taskId].data[3] <= (OUTER_BUFFER_LENGTH - 1))
         {
             if (gTasks[taskId].data[1] > 1)
             {
+                // Initialize disintegration pattern
                 index = gTasks[taskId].data[3];
-                sUnknown_0203CF10[index].buffer = Alloc(INNER_BUFFER_LENGTH);
+                sFallingTower[index].disintegrateRand = Alloc(INNER_BUFFER_LENGTH);
                 for (i = 0; i <= (INNER_BUFFER_LENGTH - 1); i++)
-                    sUnknown_0203CF10[index].buffer[i] = i;
+                    sFallingTower[index].disintegrateRand[i] = i;
+
+                // Randomize disintegration pattern
                 for (i = 0; i <= (INNER_BUFFER_LENGTH - 1); i++)
                 {
                     u16 rand1, rand2, temp;
-
-                    rand1 = Random() % 0x30;
-                    rand2 = Random() % 0x30;
-                    SWAP(sUnknown_0203CF10[index].buffer[rand2], sUnknown_0203CF10[index].buffer[rand1], temp);
+                    rand1 = Random() % INNER_BUFFER_LENGTH;
+                    rand2 = Random() % INNER_BUFFER_LENGTH;
+                    SWAP(sFallingTower[index].disintegrateRand[rand2], sFallingTower[index].disintegrateRand[rand1], temp);
                 }
                 if (gTasks[taskId].data[3] <= (OUTER_BUFFER_LENGTH - 1))
                     gTasks[taskId].data[3]++;
@@ -591,20 +612,20 @@ static void DoMirageTowerDisintegration(u8 taskId)
         {
             for (j = 0; j < 1; j++)
             {
-                sub_81BF2B8(sMirageTowerGfxBuffer,
-                            ((((OUTER_BUFFER_LENGTH - 1) - i) * INNER_BUFFER_LENGTH) + sUnknown_0203CF10[i].buffer[(sUnknown_0203CF10[i].currIndex)++]),
+                UpdateDisintegrationEffect(sMirageTowerGfxBuffer,
+                            (OUTER_BUFFER_LENGTH - 1 - i) * INNER_BUFFER_LENGTH + sFallingTower[i].disintegrateRand[sFallingTower[i].disintegrateIdx++],
                             0, INNER_BUFFER_LENGTH, 1);
             }
-            if (sUnknown_0203CF10[i].currIndex > (INNER_BUFFER_LENGTH - 1))
+            if (sFallingTower[i].disintegrateIdx > (INNER_BUFFER_LENGTH - 1))
             {
-                FREE_AND_SET_NULL(sUnknown_0203CF10[i].buffer);
+                FREE_AND_SET_NULL(sFallingTower[i].disintegrateRand);
                 gTasks[taskId].data[2]++;
                 if ((i % 2) == 1)
                     sBgShakeOffsets->bgVOFS--;
             }
         }
         LoadBgTiles(0, sMirageTowerGfxBuffer, MIRAGE_TOWER_GFX_LENGTH, 0);
-        if (sUnknown_0203CF10[OUTER_BUFFER_LENGTH - 1].currIndex > (INNER_BUFFER_LENGTH - 1))
+        if (sFallingTower[OUTER_BUFFER_LENGTH - 1].disintegrateIdx > INNER_BUFFER_LENGTH - 1)
             break;
         return;
     case 4:
@@ -617,7 +638,7 @@ static void DoMirageTowerDisintegration(u8 taskId)
         break;
     case 5:
         FREE_AND_SET_NULL(sBgShakeOffsets);
-        FREE_AND_SET_NULL(sUnknown_0203CF10);
+        FREE_AND_SET_NULL(sFallingTower);
         FREE_AND_SET_NULL(sMirageTowerGfxBuffer);
         FREE_AND_SET_NULL(sMirageTowerTilemapBuffer);
         break;
@@ -635,127 +656,128 @@ static void DoMirageTowerDisintegration(u8 taskId)
         EnableBothScriptContexts();
         break;
     }
-    gTasks[taskId].data[0]++;
+    gTasks[taskId].tState++;
 }
 
-static void DoFossilFallAndSink(u8 taskId)
+static void Task_FossilFallAndSink(u8 taskId)
 {
     u16 i;
     u8 *buffer;
 
-    switch (gTasks[taskId].data[0])
+    switch (gTasks[taskId].tState)
     {
     case 1:
-        sUnknown_0203CF0C = AllocZeroed(sizeof(*sUnknown_0203CF0C));
-        sUnknown_0203CF0C->frameImageTiles = AllocZeroed(ROOT_FOSSIL_GFX_LENGTH);
-        sUnknown_0203CF0C->frameImage = AllocZeroed(sizeof(*sUnknown_0203CF0C->frameImage));
-        sUnknown_0203CF0C->unkC = AllocZeroed(ROOT_FOSSIL_GFX_RANDOMIZER_LENGTH * sizeof(u16));
-        sUnknown_0203CF0C->unk10 = 0;
+        sFallingFossil = AllocZeroed(sizeof(*sFallingFossil));
+        sFallingFossil->frameImageTiles = AllocZeroed(sizeof(sFossil_Gfx));
+        sFallingFossil->frameImage = AllocZeroed(sizeof(*sFallingFossil->frameImage));
+        sFallingFossil->disintegrateRand = AllocZeroed(FOSSIL_DISINTEGRATE_LENGTH * sizeof(u16));
+        sFallingFossil->disintegrateIdx = 0;
         break;
     case 2:
-        buffer = sUnknown_0203CF0C->frameImageTiles;
-        for (i = 0; i < ROOT_FOSSIL_GFX_LENGTH; i++, buffer++)
-            *buffer = sRootFossil_Gfx[i];
+        buffer = sFallingFossil->frameImageTiles;
+        for (i = 0; i < sizeof(sFossil_Gfx); i++, buffer++)
+            *buffer = sFossil_Gfx[i];
         break;
     case 3:
-        sUnknown_0203CF0C->frameImage->data = sUnknown_0203CF0C->frameImageTiles;
-        sUnknown_0203CF0C->frameImage->size = ROOT_FOSSIL_GFX_LENGTH;
+        sFallingFossil->frameImage->data = sFallingFossil->frameImageTiles;
+        sFallingFossil->frameImage->size = sizeof(sFossil_Gfx);
         break;
     case 4:
         {
-            struct SpriteTemplate fossilTemplate;
-
-            fossilTemplate = gUnknown_08617E00;
-            fossilTemplate.images = (struct SpriteFrameImage *)(sUnknown_0203CF0C->frameImage);
-            sUnknown_0203CF0C->spriteId = CreateSprite(&fossilTemplate, 128, -16, 1);
-            gSprites[sUnknown_0203CF0C->spriteId].centerToCornerVecX = 0;
-            gSprites[sUnknown_0203CF0C->spriteId].data[0] = gSprites[sUnknown_0203CF0C->spriteId].pos1.x;
-            gSprites[sUnknown_0203CF0C->spriteId].data[1] = 1;
+            struct SpriteTemplate fossilTemplate = sSpriteTemplate_FallingFossil;
+            fossilTemplate.images = sFallingFossil->frameImage;
+            sFallingFossil->spriteId = CreateSprite(&fossilTemplate, 128, -16, 1);
+            gSprites[sFallingFossil->spriteId].centerToCornerVecX = 0;
+            gSprites[sFallingFossil->spriteId].data[0] = gSprites[sFallingFossil->spriteId].pos1.x;
+            gSprites[sFallingFossil->spriteId].data[1] = 1;
         }
     case 5:
-        for (i = 0; i < ROOT_FOSSIL_GFX_RANDOMIZER_LENGTH; i++)
-            sUnknown_0203CF0C->unkC[i] = i;
+        // Initialize disintegration pattern
+        for (i = 0; i < FOSSIL_DISINTEGRATE_LENGTH; i++)
+            sFallingFossil->disintegrateRand[i] = i;
         break;
     case 6:
-        for (i = 0; i < (ROOT_FOSSIL_GFX_RANDOMIZER_LENGTH * sizeof(u16)); i++)
+        // Randomize disintegration pattern
+        for (i = 0; i < FOSSIL_DISINTEGRATE_LENGTH * sizeof(u16); i++)
         {
             u16 rand1, rand2, temp;
-
-            rand1 = Random() % 0x100;
-            rand2 = Random() % 0x100;
-            SWAP(sUnknown_0203CF0C->unkC[rand2], sUnknown_0203CF0C->unkC[rand1], temp);
+            rand1 = Random() % FOSSIL_DISINTEGRATE_LENGTH;
+            rand2 = Random() % FOSSIL_DISINTEGRATE_LENGTH;
+            SWAP(sFallingFossil->disintegrateRand[rand2], sFallingFossil->disintegrateRand[rand1], temp);
         }
-        gSprites[sUnknown_0203CF0C->spriteId].callback = sub_81BF248;
+        gSprites[sFallingFossil->spriteId].callback = SpriteCB_FallingFossil;
         break;
     case 7:
-        if (gSprites[sUnknown_0203CF0C->spriteId].callback != SpriteCallbackDummy)
+        // Wait for fossil to finish falling / disintegrating
+        if (gSprites[sFallingFossil->spriteId].callback != SpriteCallbackDummy)
             return;
-        DestroySprite(&gSprites[sUnknown_0203CF0C->spriteId]);
-        FREE_AND_SET_NULL(sUnknown_0203CF0C->unkC);;
-        FREE_AND_SET_NULL(sUnknown_0203CF0C->frameImage);
-        FREE_AND_SET_NULL(sUnknown_0203CF0C->frameImageTiles);
-        FREE_AND_SET_NULL(sUnknown_0203CF0C);
+        DestroySprite(&gSprites[sFallingFossil->spriteId]);
+        FREE_AND_SET_NULL(sFallingFossil->disintegrateRand);;
+        FREE_AND_SET_NULL(sFallingFossil->frameImage);
+        FREE_AND_SET_NULL(sFallingFossil->frameImageTiles);
+        FREE_AND_SET_NULL(sFallingFossil);
         break;
     case 8:
         EnableBothScriptContexts();
         break;
     }
-
-    gTasks[taskId].data[0]++;
+    gTasks[taskId].tState++;
 }
 
-static void sub_81BF248(struct Sprite *sprite)
+static void SpriteCB_FallingFossil(struct Sprite *sprite)
 {
-    if (sUnknown_0203CF0C->unk10 >= (ROOT_FOSSIL_GFX_RANDOMIZER_LENGTH))
+    if (sFallingFossil->disintegrateIdx >= FOSSIL_DISINTEGRATE_LENGTH)
     {
+        // End animation
         sprite->callback = SpriteCallbackDummy;
     }
     else if (sprite->pos1.y >= 96)
     {
+        // Fossil has reached the ground, update disintegration animation
         u8 i;
         for (i = 0; i < 2; i++)
-            sub_81BF2B8(sUnknown_0203CF0C->frameImageTiles, sUnknown_0203CF0C->unkC[sUnknown_0203CF0C->unk10++], 0, 16, 0);
+            UpdateDisintegrationEffect(sFallingFossil->frameImageTiles, sFallingFossil->disintegrateRand[sFallingFossil->disintegrateIdx++], 0, 16, 0);
 
         StartSpriteAnim(sprite, 0);
     }
     else
     {
+        // Fossil is still falling
         sprite->pos1.y++;
     }
 }
 
-static void sub_81BF2B8(u8* a, u16 b, u8 c, u8 d, u8 e)
+static void UpdateDisintegrationEffect(u8* tiles, u16 randId, u8 c, u8 size, u8 offset)
 {
-    u8 r5, r4, r0, r2;
-    u16 var, var2;
-    u8 r2_1, r4_1;
-    u8 b2, c2;
+    u8 heightTiles, height, widthTiles, width;
+    u16 var, baseOffset;
+    u8 col, row;
+    u8 flag, tileMask;
 
-    r4 = b / d;
-    gUnknown_030012A8[0] = r4;
+    height = randId / size;
+    sDebug_DisintegrationData[0] = height;
 
-    r2 = b % d;
-    gUnknown_030012A8[1] = r2;
+    width = randId % size;
+    sDebug_DisintegrationData[1] = width;
 
-    r4_1 = r4 & 7;
-    r2_1 = r2 & 7;
-    gUnknown_030012A8[2] = r4 & 7; //should be using r4_1, but that doesn't match
-    gUnknown_030012A8[3] = r2 & 7; //"
-    
-    r0 = r2 / 8;
-    r5 = r4 / 8;
+    row = height & 7;
+    col = width & 7;
+    sDebug_DisintegrationData[2] = height & 7;
+    sDebug_DisintegrationData[3] = width & 7;
     
-    gUnknown_030012A8[4] = r2 / 8; //should be using r0, but that doesn't match
-    gUnknown_030012A8[5] = r4 / 8; //should be using r5, but that doesn't match
+    widthTiles = width / 8;
+    heightTiles = height / 8;
+    sDebug_DisintegrationData[4] = width / 8;
+    sDebug_DisintegrationData[5] = height / 8;
 
-    var = (d / 8) * (r5 * 64) + (r0 * 64);
-    gUnknown_030012A8[6] = var;
+    var = (size / 8) * (heightTiles * 64) + (widthTiles * 64);
+    sDebug_DisintegrationData[6] = var;
     
-    var2 = var + ((r4_1 * 8) + r2_1);
-    var2 /= 2;
-    gUnknown_030012A8[7] = var + ((r4_1 * 8) + r2_1); //should be using var2 with var2 being divided afterwards, but that doesn't match
+    baseOffset = var + ((row * 8) + col);
+    baseOffset /= 2;
+    sDebug_DisintegrationData[7] = var + ((row * 8) + col);
     
-    b2 = ((b % 2) ^ 1);
-    c2 = (c << (b2 << 2)) | 15 << (((b2 ^ 1) << 2));
-    a[var2 + (e * 32)] &= c2;
+    flag = ((randId % 2) ^ 1);
+    tileMask = (c << (flag << 2)) | 15 << (((flag ^ 1) << 2));
+    tiles[baseOffset + (offset * 32)] &= tileMask;
 }