Decompile no0 Ghost functions (#1889)

`EntityGhostEnemySpawner` / `func_us_801D606C` matching both
PSX: https://decomp.me/scratch/CrIPN
PSP: https://decomp.me/scratch/RyIgW

`EntityGhostEnemy` / `func_us_801D5E4C` matching both
PSX: https://decomp.me/scratch/YEAXd
PSP: https://decomp.me/scratch/HpJ4I

Also extracted the data and split files.

That's for these cute little fellas:

![image](https://github.com/user-attachments/assets/516928da-7969-4908-93b7-6ced09f6dd79)

config/splat.us.stno0.yaml

@@ -56,6 +56,8 @@ segments:
       - [0x1C14, data]
       - [0x1C34, data, clock_room]
       - [0x1CA0, data]
+      - [0x1FC8, .data, e_ghost]
+      - [0x1FE8, data]
       - [0x2194, .data, e_slinger]
       - [0x2268, data]
       - [0x2478, .data, e_axe_knight]
@@ -102,6 +104,7 @@ segments:
       - [0x4E2E0, c]
       - [0x4E654, c, e_stage_name]
       - [0x4F4A8, c, unk_4F4A8]
+      - [0x55E4C, c, e_ghost]
       - [0x56254, c, e_marionette]
       - [0x575E4, c, e_slinger]
       - [0x57C20, c, 57C20]

config/symbols.us.stno0.txt

@@ -9,6 +9,7 @@ g_EInitUnkId13 = 0x80180AD0;
 g_EInitCommon = 0x80180AE8;
 g_EInitDamageNum = 0x80180B18;
 g_EInitElevator = 0x80180B60;
+g_EInitGhostEnemy = 0x80180B9C;
 g_EInitSlinger = 0x80180BB4;
 g_EInitSlingerPieces = 0x80180BC0;
 g_EInitAxeKnight = 0x80180BFC;
@@ -184,6 +185,8 @@ EntityClockRoomUnused = 0x801CE2D8;
 StageNamePopupHelper = 0x801CE654;
 EntityStageNamePopup = 0x801CE824;
 func_801CD78C = 0x801D2374;
+EntityGhostEnemy = 0x801D5E4C;
+EntityGhostEnemySpawner = 0x801D606C;
 EntitySlinger = 0x801D7670;
 EntitySlingerPieces = 0x801D7B40;
 func_801C3F9C = 0x801DAEBC;

include/entity.h

@@ -2036,6 +2036,18 @@ typedef struct {
     /* 0xA4 */ struct Primitive* unkA4;
 } ET_801D9264;
 
+typedef struct {
+    /* 0x7C */ s32 : 32;
+    /* 0x80 */ s16 timer;
+} ET_GhostEnemySpawner;
+
+typedef struct {
+    /* 0x7C */ s32 : 32;
+    /* 0x80 */ s16 angle;
+    /* 0x82 */ s16 : 16;
+    /* 0x84 */ u32 speed;
+} ET_GhostEnemy;
+
 // ====== RIC ENTITIES ======
 
 // ==========================
@@ -2220,6 +2232,8 @@ typedef union { // offset=0x7C
     ET_OuijaTableContents ouijaTableContents;
     ET_FleaMan fleaMan;
     ET_801D9264 et_801D9264;
+    ET_GhostEnemy ghostEnemy;
+    ET_GhostEnemySpawner ghostEnemySpawner;
 } Ext;
 
 #define SYNC_FIELD(struct1, struct2, field)                                    \

include/sfx.h

@@ -553,6 +553,7 @@ enum Sfx {
     SFX_SLOGRA_ROAR_DEFEAT,
     SFX_SLOGRA_PAIN_A, // Used for Gaibon
     SFX_SLOGRA_PAIN_B,
+    SFX_GHOST_ENEMY_HOWL = 1849,
     SFX_CLOCK_BELL = 1958,
     SFX_CLOCK_ROOM_TICK = 1961
 };

src/st/no0/e_ghost.c

@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+#include "no0.h"
+
+static u8 anim_phase_in[] = {0x03, 0x01, 0x03, 0x02, 0x03, 0x03, 0x03,
+                             0x04, 0x03, 0x05, 0x03, 0x06, 0xFF, 0x00};
+static u8 anim_burning[] = {0x03, 0x07, 0x03, 0x08, 0x00};
+static s16 min_max_positions[] = {
+    416, 1152, 288, 480}; // xMin, xMax, yMin, yMax
+
+void EntityGhostEnemy(Entity* self) {
+    Entity* newEntity;
+    s16 angle;
+    s32 speed;
+
+    if (self->flags & FLAG_DEAD) {
+        PlaySfxPositional(SFX_GHOST_ENEMY_HOWL);
+        newEntity = AllocEntity(&g_Entities[224], &g_Entities[256]);
+        if (newEntity != NULL) {
+            CreateEntityFromEntity(2, self, newEntity);
+            newEntity->params = 1;
+        }
+        DestroyEntity(self);
+        return;
+    }
+
+    switch (self->step) {
+    case 0:
+        InitializeEntity(g_EInitGhostEnemy);
+        self->hitboxOffX = 1;
+        self->hitboxOffY = -1;
+        self->hitboxState = 0;
+        // fallthrough
+    case 1:
+        self->facingLeft = (GetSideToPlayer() & 1) ^ 1;
+        self->step++;
+        break;
+    case 2:
+        if (!AnimateEntity(anim_phase_in, self)) {
+            self->hitboxState = 7;
+            SetStep(3);
+        }
+        break;
+    case 3:
+        if (!AnimateEntity(anim_burning, self)) {
+            self->facingLeft = (GetSideToPlayer() & 1) ^ 1;
+        }
+        MoveEntity();
+
+        // Seek towards player
+        newEntity = &PLAYER;
+        angle = GetAngleBetweenEntities(self, newEntity);
+        angle = GetNormalizedAngle(16, self->ext.ghostEnemy.angle, angle);
+        speed = self->ext.ghostEnemy.speed;
+        self->velocityX = (speed * rcos(angle)) >> 12;
+        self->velocityY = (speed * rsin(angle)) >> 12;
+        self->ext.ghostEnemy.angle = angle;
+
+        speed += FIX(0.015625);
+        if (speed > FIX(0.75)) {
+            speed = FIX(0.75);
+        }
+        // If player is hit, bounce back off in opposite direction
+        if (self->hitFlags) {
+            speed = FIX(-0.75);
+        }
+        self->ext.ghostEnemy.speed = speed;
+        break;
+    }
+}
+
+void EntityGhostEnemySpawner(Entity* self) {
+    Entity* entity;
+    s32 xPos;
+    s32 yPos;
+    s16* minMaxPositions;
+
+    if (!self->step) {
+        InitializeEntity(D_us_80180A88);
+        self->flags &= ~FLAG_UNK_2000;
+        self->ext.ghostEnemySpawner.timer = 1;
+    }
+    if (!--self->ext.ghostEnemySpawner.timer) {
+        self->ext.ghostEnemySpawner.timer = (Random() & 47) + 48;
+        entity = &PLAYER;
+        xPos = g_Tilemap.scrollX.i.hi + entity->posX.i.hi;
+        yPos = g_Tilemap.scrollY.i.hi + entity->posY.i.hi;
+        if (self->params) {
+            minMaxPositions = &min_max_positions[(self->params - 1) * 4];
+            if (xPos < minMaxPositions[0] || xPos > minMaxPositions[1] ||
+                yPos < minMaxPositions[2] || yPos > minMaxPositions[3]) {
+                return;
+            }
+        }
+
+        entity = AllocEntity(&g_Entities[160], &g_Entities[164]);
+        if (entity != NULL) {
+            CreateEntityFromEntity(E_GHOST_ENEMY, self, entity);
+            entity->zPriority = 170;
+            entity->posX.i.hi = xPos - g_Tilemap.scrollX.i.hi;
+            entity->posY.i.hi = yPos - g_Tilemap.scrollY.i.hi;
+            xPos = (Random() & 63) + 48;
+            if (Random() & 1) {
+                entity->posX.i.hi += xPos;
+            } else {
+                entity->posX.i.hi -= xPos;
+            }
+
+            yPos = ((Random() & 127) - 64);
+            entity->posY.i.hi += yPos;
+        }
+    }
+}

src/st/no0/no0.h

@@ -30,6 +30,7 @@ typedef enum EntityIDs {
     /* 0x14 */ E_ID_14 = 0x14,
     /* 0x15 */ E_GREY_PUFF,
     /* 0x1D */ E_CLOCK_ROOM_SHADOW = 0x20,
+    /* 0x37 */ E_GHOST_ENEMY = 0x37,
     /* 0x3B */ E_SLINGER_THROWN_BONE = 0x3B,
     /* 0x3C */ E_SLINGER_PIECES,
     /* 0x44 */ E_ID_44 = 0x44,
@@ -51,22 +52,26 @@ extern u16 g_EInitCommon[];
 extern u16 g_EInitParticle[];
 
 // Axe knight
-extern u16 g_EInitAxeKnightAxe[];
+extern EInit g_EInitAxeKnightAxe;
 
 // Skeleton
-extern u16 g_EInitSkeleton[];
-extern u16 g_EInitSkeletonPieces[];
-extern u16 g_EInitSkeletonBone[];
+extern EInit g_EInitSkeleton;
+extern EInit g_EInitSkeletonPieces;
+extern EInit g_EInitSkeletonBone;
 
 // Ouija Table
-extern u16 g_EInitOuijaTable[];
-extern u16 g_EInitOuijaTableComponent[];
+extern EInit g_EInitOuijaTable;
+extern EInit g_EInitOuijaTableComponent;
 
 // Flea Man
-extern u16 g_EInitFleaMan[];
+extern EInit g_EInitFleaMan;
+
+// Ghost (enemy)
+extern EInit g_EInitGhostEnemy;
 
 // Clock room
-extern u16 g_Statues[];
+extern EInit g_Statues;
 
-// Clocks?
-extern u16 D_us_80180A88[];
+// Seems shared between a number of entities - ghost spawner,
+// func_us_801C2B24 (clocks?), func_us_801CC750
+extern EInit D_us_80180A88;

src/st/no0/unk_4F4A8.c

@@ -132,7 +132,3 @@ INCLUDE_ASM("st/no0/nonmatchings/unk_4F4A8", func_us_801D52E0);
 INCLUDE_ASM("st/no0/nonmatchings/unk_4F4A8", func_us_801D5384);
 
 INCLUDE_ASM("st/no0/nonmatchings/unk_4F4A8", func_us_801D542C);
-
-INCLUDE_ASM("st/no0/nonmatchings/unk_4F4A8", func_us_801D5E4C);
-
-INCLUDE_ASM("st/no0/nonmatchings/unk_4F4A8", func_us_801D606C);