From 5a0bc4aaa14b9424bb62b06d8df0f9788fa853f3 Mon Sep 17 00:00:00 2001
From: gamezter <gamezter93@gmail.com>
Date: Thu, 20 Feb 2025 15:35:50 -0500
Subject: [PATCH] Decompile `lib` func_us_801CD318

---
 include/entity.h       |  15 ++++
 src/st/lib/unk_4C984.c | 188 ++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 201 insertions(+), 2 deletions(-)

diff --git a/include/entity.h b/include/entity.h
index f127664bf9..0e3a5b7980 100644
--- a/include/entity.h
+++ b/include/entity.h
@@ -2870,6 +2870,20 @@ typedef struct {
     /* 0x84 */ s16 unk84;
 } ET_801B56E4;
 
+typedef struct {
+    /* 0x7C */ s16 unk7C;
+    /* 0x7E */ s16 unk7E;
+    /* 0x80 */ s16 unk80;
+    /* 0x82 */ s16 unk82;
+    /* 0x84 */ s32 unk84;
+    /* 0x88 */ s32 unk88;
+    /* 0x8C */ s32 : 32;
+    /* 0x90 */ s16 unk90;
+    /* 0x92 */ s16 unk92;
+    /* 0x94 */ s16 unk94;
+    /* 0x96 */ s16 unk96;
+} ET_801CD318;
+
 typedef union { // offset=0x7C
     struct Primitive* prim;
     ET_Placeholder ILLEGAL;
@@ -3119,6 +3133,7 @@ typedef union { // offset=0x7C
     ET_801AE8E8 et_801AE8E8;
     ET_FleaArmor fleaArmor;
     ET_801B56E4 et_801B56E4;
+    ET_801CD318 et_801CD318;
 } Ext;
 
 #define SYNC_FIELD(struct1, struct2, field)                                    \
diff --git a/src/st/lib/unk_4C984.c b/src/st/lib/unk_4C984.c
index 517fe1da58..cb38360967 100644
--- a/src/st/lib/unk_4C984.c
+++ b/src/st/lib/unk_4C984.c
@@ -1,11 +1,195 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
-#include "common.h"
+#include "lib.h"
+#include "../pfn_entity_update.h"
 
 INCLUDE_ASM("st/lib/nonmatchings/unk_4C984", func_us_801CCED0);
 
 INCLUDE_ASM("st/lib/nonmatchings/unk_4C984", func_us_801CCF6C);
 
-INCLUDE_ASM("st/lib/nonmatchings/unk_4C984", func_us_801CD318);
+extern u16 D_us_801808C0[];
+extern s32 D_us_80181ACC;
+extern AnimationFrame D_us_80182AF0[];
+extern AnimationFrame D_us_80182B38[];
+
+void func_us_801CD318(Entity* self) {
+    Entity* tempEntity;
+    Primitive* prim;
+    s16 angle;
+    s32 xOffset;
+    s32 yOffset;
+
+    if ((self->params & 0x10) && (D_us_80181ACC & 2)) {
+        self->hitFlags |= 3;
+        self->flags |= FLAG_DEAD;
+    }
+    if (self->hitFlags & 3) {
+        if (self->step < 4) {
+            if (self->flags & FLAG_DEAD) {
+                PlaySfxPositional(0x73B);
+                self->hitboxState = 0;
+                self->ext.et_801CD318.unk90 = 0;
+                self->ext.et_801CD318.unk96 = 0x100;
+                self->drawMode |= DRAW_TPAGE;
+                self->step = 4;
+                self->ext.et_801CD318.unk82 = 0;
+            } else if (self->step != 3) {
+                PlaySfxPositional(0x73A);
+                self->ext.et_801CD318.unk90 = 0;
+                self->step_s = self->step;
+                self->step = 3;
+            }
+        }
+    }
+    switch (self->step) {
+    case 0:
+        InitializeEntity(D_us_801808C0);
+        if (self->params == 0) {
+            self->anim = D_us_80182AF0;
+        } else {
+            self->anim = D_us_80182B38;
+        }
+        self->primIndex = g_api.AllocPrimitives(PRIM_TILE, 1);
+        if (self->primIndex == -1) {
+            DestroyEntity(self);
+            return;
+        }
+        self->flags |= FLAG_HAS_PRIMS;
+        self->drawFlags = FLAG_DRAW_ROTY | FLAG_DRAW_ROTX;
+        self->rotY = 0x100;
+        self->rotX = 0x100;
+        prim = &g_PrimBuf[self->primIndex];
+        prim->x0 = self->posX.i.hi;
+        prim->y0 = self->posY.i.hi;
+        prim->drawMode = DRAW_HIDE | DRAW_UNK02;
+        if (self->params == 0) {
+            self->ext.et_801CD318.unk84 = 0x3800;
+            self->ext.et_801CD318.unk88 = 0x2000;
+            self->ext.et_801CD318.unk92 = 8;
+            self->ext.et_801CD318.unk94 = 8;
+        } else {
+            self->ext.et_801CD318.unk84 = 0x4000;
+            self->ext.et_801CD318.unk88 = 0x1800;
+            self->ext.et_801CD318.unk92 = -0xA;
+            self->ext.et_801CD318.unk94 = 0xA;
+        }
+        if (self->params & 0x10) {
+            self->ext.et_801CD318.unk84 = 0;
+            self->flags |= FLAG_UNK_2000;
+            self->hitboxState = 0;
+            self->animCurFrame = 0;
+            self->step = 0x20;
+        }
+        break;
+
+    case 32:
+        func_us_801BB8DC(0);
+        break;
+
+    case 1:
+        self->ext.et_801CD318.unk7C += self->ext.et_801CD318.unk92;
+        self->ext.et_801CD318.unk7E += 0x40;
+        if (g_pads[0].tapped & 0x80) {
+            self->step++;
+            self->ext.et_801CD318.unk92 = self->ext.et_801CD318.unk92 * 2;
+            self->ext.et_801CD318.unk80 = 0;
+        }
+        angle = abs(self->ext.et_801CD318.unk92);
+        if (angle > self->ext.et_801CD318.unk94) {
+            if (self->ext.et_801CD318.unk92 > 0) {
+                self->ext.et_801CD318.unk92--;
+            } else {
+                self->ext.et_801CD318.unk92++;
+            }
+        }
+        break;
+
+    case 2:
+        self->ext.et_801CD318.unk7C += self->ext.et_801CD318.unk92;
+        self->ext.et_801CD318.unk7E += 0x40;
+        angle = self->ext.et_801CD318.unk80;
+        if (self->ext.et_801CD318.unk80 < 0x1000) {
+            self->ext.et_801CD318.unk80 += 0x20;
+            self->ext.et_801CD318.unk84 += rsin(angle) >> 4;
+            self->ext.et_801CD318.unk88 += rsin(angle) >> 4;
+        } else {
+            self->ext.et_801CD318.unk80 += 0x40;
+            self->ext.et_801CD318.unk84 -= rsin(angle) >> 5;
+            self->ext.et_801CD318.unk88 -= rsin(angle) >> 5;
+        }
+        if (self->ext.et_801CD318.unk80 == 0x2000) {
+            self->step--;
+            self->ext.et_801CD318.unk92 = self->ext.et_801CD318.unk92 / 2;
+        }
+        break;
+
+    case 3:
+        angle = self->ext.et_801CD318.unk90 & 0x7FF;
+        self->rotY = (rsin(angle) >> 4) + 0x100;
+        self->rotX = 0x100 - (rsin(angle) >> 6);
+        self->ext.et_801CD318.unk90 += 0x80;
+        if (self->ext.et_801CD318.unk90 == 0x1000) {
+            self->rotY = 0x100;
+            self->rotX = 0x100;
+            self->step = self->step_s;
+            self->ext.et_801CD318.unk92 = -self->ext.et_801CD318.unk92 * 2;
+        }
+        break;
+
+    case 4:
+        if (self->ext.et_801CD318.unk82 == 0x20) {
+            PlaySfxPositional(SFX_NOISE_SWEEP_DOWN_A);
+        }
+        angle = self->ext.et_801CD318.unk90 & 0x7FF;
+        self->rotY = self->ext.et_801CD318.unk96 + (rsin(angle) >> 4);
+        self->rotX = self->ext.et_801CD318.unk96 - (rsin(angle) >> 6);
+        self->ext.et_801CD318.unk90 += 0x80;
+        self->posY.val += self->velocityY;
+        self->velocityY += 0x400;
+        self->ext.et_801CD318.unk96--;
+        if (self->ext.et_801CD318.unk96 < 0x60) {
+            self->ext.et_801CD318.unk96 = 0x60;
+        }
+        if ((self->ext.et_801CD318.unk82 & 1) == 0) {
+            tempEntity = g_api.GetFreeEntity(0xE0, 0x100);
+            if (tempEntity != NULL) {
+                DestroyEntity(tempEntity);
+                tempEntity->entityId = 2;
+                tempEntity->pfnUpdate =
+                    PfnEntityUpdates[tempEntity->entityId - 1];
+                tempEntity->params = 0;
+                tempEntity->zPriority = self->zPriority + 2;
+                tempEntity->posX.i.hi =
+                    (self->posX.i.hi + (rand() & 0x1F)) - 0x10;
+                tempEntity->posY.i.hi =
+                    (self->posY.i.hi + (rand() & 0x1F)) - 0x10;
+                tempEntity->drawMode = DRAW_TPAGE;
+            }
+        }
+        if (self->posY.i.hi > 0x100) {
+            DestroyEntity(self);
+            return;
+        }
+        break;
+    }
+    g_api.UpdateAnim(NULL, NULL);
+    self->ext.et_801CD318.unk82++;
+    if ((self->ext.et_801CD318.unk82 & 7) == 0) {
+        if (self->params == 0) {
+            func_us_801CCED0(0);
+        } else {
+            func_us_801CCED0(1);
+        }
+    }
+    if (self->step != 4) {
+        angle = self->ext.et_801CD318.unk7C;
+        xOffset = ((rcos(angle) * self->ext.et_801CD318.unk84) >> 8) << 4;
+        yOffset = -((rsin(angle) * self->ext.et_801CD318.unk88) >> 8) << 4;
+        yOffset -= (rsin(self->ext.et_801CD318.unk7E) << 1) << 4;
+        prim = &g_PrimBuf[self->primIndex];
+        self->posX.i.hi = prim->x0 + (xOffset >> 0x10);
+        self->posY.i.hi = prim->y0 + (yOffset >> 0x10);
+    }
+}
 
 // Ectoplasm
 INCLUDE_ASM("st/lib/nonmatchings/unk_4C984", func_us_801CD9EC);