Document z_horse.c and related actors (#2278)

* document z_horse.h

* .bss

* suggestions and more comments

* bss

* INGORACE -> INGO_RACE

* format header macros

* FIx incorrect type comparision

* EnInMode -> EnInStartMode

* R_EXITED_SCENE_RIDING_HORSE

6 files changed, 165 insertions, 112 deletions

diff --git a/src/code/z_actor.c b/src/code/z_actor.c
index e58729629..66b9601e5 100644
--- a/src/code/z_actor.c
+++ b/src/code/z_actor.c
@@ -4,6 +4,7 @@
 #include "rand.h"
 #include "terminal.h"
 #include "versions.h"
+#include "z64horse.h"
 
 #include "overlays/actors/ovl_Arms_Hook/z_arms_hook.h"
 #include "overlays/actors/ovl_En_Part/z_en_part.h"
@@ -1139,7 +1140,7 @@ void Actor_SwapHookshotAttachment(PlayState* play, Actor* srcActor, Actor* destA
     srcActor->flags &= ~ACTOR_FLAG_HOOKSHOT_ATTACHED;
 }
 
-void func_8002DE74(PlayState* play, Player* player) {
+void Actor_RequestHorseCameraSetting(PlayState* play, Player* player) {
     if ((play->roomCtx.curRoom.type != ROOM_TYPE_4) && Play_CamIsNotFixed(play)) {
         Camera_RequestSetting(Play_GetCamera(play, CAM_ID_MAIN), CAM_SET_HORSE);
     }
@@ -1156,8 +1157,8 @@ int func_8002DEEC(Player* player) {
            (player->csAction != PLAYER_CSACTION_NONE);
 }
 
-void func_8002DF18(PlayState* play, Player* player) {
-    func_8006DC68(play, player);
+void Actor_InitPlayerHorse(PlayState* play, Player* player) {
+    Horse_InitPlayerHorse(play, player);
 }
 
 /**
diff --git a/src/code/z_camera.c b/src/code/z_camera.c
index d5c97c109..e4090d484 100644
--- a/src/code/z_camera.c
+++ b/src/code/z_camera.c
@@ -5,7 +5,7 @@
 #include "overlays/actors/ovl_En_Horse/z_en_horse.h"
 
 #pragma increment_block_number "gc-eu:192 gc-eu-mq:192 gc-jp:192 gc-jp-ce:192 gc-jp-mq:192 gc-us:192 gc-us-mq:192" \
-                               "ntsc-1.0:192 ntsc-1.1:192 ntsc-1.2:192 pal-1.0:192 pal-1.1:192"
+                               "ntsc-1.0:128 ntsc-1.1:128 ntsc-1.2:128 pal-1.0:128 pal-1.1:128"
 
 s16 Camera_RequestSettingImpl(Camera* camera, s16 requestedSetting, s16 flags);
 s32 Camera_RequestModeImpl(Camera* camera, s16 requestedMode, u8 forceModeChange);
@@ -3639,7 +3639,7 @@ s32 Camera_KeepOn3(Camera* camera) {
 }
 
 #pragma increment_block_number "gc-eu:128 gc-eu-mq:128 gc-jp:128 gc-jp-ce:128 gc-jp-mq:128 gc-us:128 gc-us-mq:128" \
-                               "ntsc-1.0:83 ntsc-1.1:83 ntsc-1.2:83 pal-1.0:81 pal-1.1:81"
+                               "ntsc-1.0:144 ntsc-1.1:144 ntsc-1.2:144 pal-1.0:142 pal-1.1:142"
 
 s32 Camera_KeepOn4(Camera* camera) {
     static Vec3f D_8015BD50;
diff --git a/src/code/z_horse.c b/src/code/z_horse.c
index d3d66c3de..2935a66f8 100644
--- a/src/code/z_horse.c
+++ b/src/code/z_horse.c
@@ -1,30 +1,47 @@
-#include "global.h"
 #include "terminal.h"
+#include "z_lib.h"
+#include "regs.h"
+#include "z64horse.h"
+#include "z64play.h"
+#include "z64player.h"
 #include "src/overlays/actors/ovl_En_Horse/z_en_horse.h"
 
-s32 func_8006CFC0(s32 sceneId) {
+/**
+ * Tests if the player horse can be spawned
+ *
+ * @param sceneId the checked scene
+ * @return true if the player horse can appear in the scene, else false
+ */
+s32 Horse_CanSpawn(s32 sceneId) {
     s32 validSceneIds[] = { SCENE_HYRULE_FIELD, SCENE_LAKE_HYLIA, SCENE_GERUDO_VALLEY, SCENE_GERUDOS_FORTRESS,
                             SCENE_LON_LON_RANCH };
     s32 i;
 
     for (i = 0; i < ARRAY_COUNT(validSceneIds); i++) {
         if (sceneId == validSceneIds[i]) {
-            return 1;
+            return true;
         }
     }
 
-    return 0;
+    return false;
 }
 
-void func_8006D074(PlayState* play) {
+/**
+ * Sets horseData to a neutral spawn in Hyrule Field
+ */
+void Horse_ResetHorseData(PlayState* play) {
     gSaveContext.save.info.horseData.sceneId = SCENE_HYRULE_FIELD;
     gSaveContext.save.info.horseData.pos.x = -1840;
     gSaveContext.save.info.horseData.pos.y = 72;
     gSaveContext.save.info.horseData.pos.z = 5497;
-    gSaveContext.save.info.horseData.angle = -27353;
+    gSaveContext.save.info.horseData.angle = -0x6AD9;
 }
 
-void func_8006D0AC(PlayState* play) {
+/**
+ * Forces the player horse to spawn in a safe spot if the current spawn is in Lake Hylia
+ * This prevents the horse from spawning underwater after obtaining the Water Medallion
+ */
+void Horse_FixLakeHyliaPosition(PlayState* play) {
     if (gSaveContext.save.info.horseData.sceneId == SCENE_LAKE_HYLIA) {
         gSaveContext.save.info.horseData.sceneId = SCENE_LAKE_HYLIA;
         gSaveContext.save.info.horseData.pos.x = -2065;
@@ -41,49 +58,59 @@ typedef struct HorseSpawn {
     /* 0x0A */ s16 type;
 } HorseSpawn;
 
-void func_8006D0EC(PlayState* play, Player* player) {
+void Horse_SetupInGameplay(PlayState* play, Player* player) {
     s32 i;
     HorseSpawn horseSpawns[] = {
-        { SCENE_HYRULE_FIELD, -460, 100, 6640, 0, 2 },  { SCENE_LAKE_HYLIA, -1929, -1025, 768, 0, 2 },
-        { SCENE_GERUDO_VALLEY, 2566, -259, 767, 0, 2 }, { SCENE_GERUDOS_FORTRESS, -328, 10, 953, 0, 2 },
-        { SCENE_LON_LON_RANCH, 928, 0, -2280, 0, 2 },
+        { SCENE_HYRULE_FIELD, -460, 100, 6640, 0, HORSE_PTYPE_INACTIVE },
+        { SCENE_LAKE_HYLIA, -1929, -1025, 768, 0, HORSE_PTYPE_INACTIVE },
+        { SCENE_GERUDO_VALLEY, 2566, -259, 767, 0, HORSE_PTYPE_INACTIVE },
+        { SCENE_GERUDOS_FORTRESS, -328, 10, 953, 0, HORSE_PTYPE_INACTIVE },
+        { SCENE_LON_LON_RANCH, 928, 0, -2280, 0, HORSE_PTYPE_INACTIVE },
     };
 
-    if ((AREG(6) != 0) && (Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) || (DREG(1) != 0))) {
-        player->rideActor = Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, player->actor.world.pos.x,
-                                        player->actor.world.pos.y, player->actor.world.pos.z, player->actor.shape.rot.x,
-                                        player->actor.shape.rot.y, player->actor.shape.rot.z, 9);
+    if (R_EXITED_SCENE_RIDING_HORSE &&
+        (Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) || R_DEBUG_FORCE_EPONA_OBTAINED)) {
+        // Player entering scene on top of horse
+        player->rideActor =
+            Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, player->actor.world.pos.x, player->actor.world.pos.y,
+                        player->actor.world.pos.z, player->actor.shape.rot.x, player->actor.shape.rot.y,
+                        player->actor.shape.rot.z, HORSE_PTYPE_PLAYER_SPAWNED_RIDING);
 
         ASSERT(player->rideActor != NULL, "player->ride.actor != NULL", "../z_horse.c", 343);
 
         Actor_MountHorse(play, player, player->rideActor);
-        func_8002DE74(play, player);
+        Actor_RequestHorseCameraSetting(play, player);
         gSaveContext.save.info.horseData.sceneId = play->sceneId;
-
         if (play->sceneId == SCENE_GERUDOS_FORTRESS) {
             player->rideActor->room = -1;
         }
     } else if ((play->sceneId == SCENE_GERUDOS_FORTRESS) && (gSaveContext.minigameState == 3)) {
+        // Completed Horseback Archery Minigame
         Actor* horseActor;
         gSaveContext.minigameState = 0;
-        horseActor = Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, 3586.0f, 1413.0f, -402.0f, 0, 0x4000, 0, 1);
+        horseActor =
+            Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, 3586.0f, 1413.0f, -402.0f, 0, 0x4000, 0, HORSE_PTYPE_1);
         horseActor->room = -1;
     } else if ((gSaveContext.save.entranceIndex == ENTR_LON_LON_RANCH_7) &&
                GET_EVENTCHKINF(EVENTCHKINF_EPONA_OBTAINED)) {
+        // Completed Horse Race
         Actor* horseActor =
-            Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, -25.0f, 0.0f, -1600.0f, 0, -0x4000, 0, 1);
+            Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, -25.0f, 0.0f, -1600.0f, 0, -0x4000, 0, HORSE_PTYPE_1);
         ASSERT(horseActor != NULL, "horse_actor != NULL", "../z_horse.c", 389);
     } else if ((play->sceneId == gSaveContext.save.info.horseData.sceneId) &&
-               (Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) || DREG(1) != 0)) {
+               (Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) || R_DEBUG_FORCE_EPONA_OBTAINED)) {
+        // Player enters a scene where the horse was left previously
         PRINTF(T("馬存在によるセット %d %d %d\n", "Set by existence of horse %d %d %d\n"),
-               gSaveContext.save.info.horseData.sceneId, Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED), DREG(1));
+               gSaveContext.save.info.horseData.sceneId, Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED),
+               R_DEBUG_FORCE_EPONA_OBTAINED);
 
-        if (func_8006CFC0(gSaveContext.save.info.horseData.sceneId)) {
+        if (Horse_CanSpawn(gSaveContext.save.info.horseData.sceneId)) {
             Actor* horseActor =
                 Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, gSaveContext.save.info.horseData.pos.x,
                             gSaveContext.save.info.horseData.pos.y, gSaveContext.save.info.horseData.pos.z, 0,
-                            gSaveContext.save.info.horseData.angle, 0, 1);
+                            gSaveContext.save.info.horseData.angle, 0, HORSE_PTYPE_1);
             ASSERT(horseActor != NULL, "horse_actor != NULL", "../z_horse.c", 414);
+
             if (play->sceneId == SCENE_GERUDOS_FORTRESS) {
                 horseActor->room = -1;
             }
@@ -93,13 +120,16 @@ void func_8006D0EC(PlayState* play, Player* player) {
                 T("Horse_SetNormal():%d セットスポットまずいです。\n", "Horse_SetNormal():%d set spot is no good.\n"),
                 gSaveContext.save.info.horseData.sceneId);
             PRINTF(VT_RST);
-            func_8006D074(play);
+            Horse_ResetHorseData(play);
         }
-    } else if ((play->sceneId == SCENE_LON_LON_RANCH) && !Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) &&
-               (DREG(1) == 0)) {
-        Actor* horseActor = Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, 0.0f, 0.0f, -500.0f, 0, 0, 0, 1);
+    } else if ((play->sceneId == SCENE_LON_LON_RANCH) &&
+               !(Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) || R_DEBUG_FORCE_EPONA_OBTAINED)) {
+        // Player spawns in Lon-Lon Ranch without owning Epona
+        Actor* horseActor =
+            Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, 0.0f, 0.0f, -500.0f, 0, 0, 0, HORSE_PTYPE_1);
         ASSERT(horseActor != NULL, "horse_actor != NULL", "../z_horse.c", 443);
-    } else if (Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) || (DREG(1) != 0)) {
+    } else if (Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) || R_DEBUG_FORCE_EPONA_OBTAINED) {
+        // Player owns Epona, but isn't riding her and the current scene is not the same as the horse's last location.
         for (i = 0; i < ARRAY_COUNT(horseSpawns); i++) {
             HorseSpawn* horseSpawn = &horseSpawns[i];
             if (horseSpawn->sceneId == play->sceneId) {
@@ -107,134 +137,145 @@ void func_8006D0EC(PlayState* play, Player* player) {
                     Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, horseSpawn->pos.x, horseSpawn->pos.y,
                                 horseSpawn->pos.z, 0, horseSpawn->angle, 0, horseSpawn->type);
                 ASSERT(horseActor != NULL, "horse_actor != NULL", "../z_horse.c", 466);
+
                 if (play->sceneId == SCENE_GERUDOS_FORTRESS) {
                     horseActor->room = -1;
                 }
-
                 break;
             }
         }
-    } else if (!Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED)) {
-        if ((DREG(1) == 0) && (play->sceneId == SCENE_LON_LON_BUILDINGS) && !IS_DAY) {
-            Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, 0.0f, 0.0f, -60.0f, 0, 0x7360, 0, 1);
-        }
+    } else if (!(Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) || R_DEBUG_FORCE_EPONA_OBTAINED) &&
+               (play->sceneId == SCENE_LON_LON_BUILDINGS) && !IS_DAY) {
+        Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, 0.0f, 0.0f, -60.0f, 0, 0x7360, 0, HORSE_PTYPE_1);
     }
 }
 
-typedef struct struct_8011F9B8 {
+typedef struct HorseCutsceneSpawn {
     /* 0x00 */ s16 sceneId;
     /* 0x04 */ s32 cutsceneIndex;
     /* 0x08 */ Vec3s pos;
     /* 0x0E */ s16 angle;
     /* 0x10 */ s16 type;
-} struct_8011F9B8;
-
-void func_8006D684(PlayState* play, Player* player) {
-    static struct_8011F9B8 D_8011F9B8[] = {
-        { SCENE_GERUDOS_FORTRESS, 0xFFF0, { 3600, 1413, 360 }, 0x8001, 8 },
-        { SCENE_LON_LON_RANCH, 0xFFF0, { -250, 1, -1580 }, 0x4000, 6 },
-        { SCENE_LON_LON_RANCH, 0xFFF1, { 0, 0, 0 }, 0x0000, 5 },
-        { SCENE_LON_LON_RANCH, 0xFFF5, { 0, 0, 0 }, 0x0000, 7 },
-        { SCENE_HYRULE_FIELD, 0xFFF3, { -2961, 313, 7700 }, 0x0000, 7 },
-        { SCENE_HYRULE_FIELD, 0xFFF4, { -1900, 313, 7015 }, 0x0000, 7 },
-        { SCENE_HYRULE_FIELD, 0xFFF5, { -4043, 313, 6933 }, 0x0000, 7 },
-        { SCENE_HYRULE_FIELD, 0xFFF6, { -4043, 313, 6933 }, 0x0000, 7 },
+} HorseCutsceneSpawn;
+
+void Horse_SetupInCutscene(PlayState* play, Player* player) {
+    static HorseCutsceneSpawn horseSpawns[] = {
+        { SCENE_GERUDOS_FORTRESS, 0xFFF0, { 3600, 1413, 360 }, 0x8001, HORSE_PTYPE_HORSEBACK_ARCHERY },
+        { SCENE_LON_LON_RANCH, 0xFFF0, { -250, 1, -1580 }, 0x4000, HORSE_PTYPE_6 },  // Horse Race
+        { SCENE_LON_LON_RANCH, 0xFFF1, { 0, 0, 0 }, 0x0000, HORSE_PTYPE_5 },         // Learned Epona's Song
+        { SCENE_LON_LON_RANCH, 0xFFF5, { 0, 0, 0 }, 0x0000, HORSE_PTYPE_7 },         // Credits
+        { SCENE_HYRULE_FIELD, 0xFFF3, { -2961, 313, 7700 }, 0x0000, HORSE_PTYPE_7 }, // Title Screen
+        { SCENE_HYRULE_FIELD, 0xFFF4, { -1900, 313, 7015 }, 0x0000, HORSE_PTYPE_7 },
+        { SCENE_HYRULE_FIELD, 0xFFF5, { -4043, 313, 6933 }, 0x0000, HORSE_PTYPE_7 }, // Credits
+        { SCENE_HYRULE_FIELD, 0xFFF6, { -4043, 313, 6933 }, 0x0000, HORSE_PTYPE_7 }, // Unused. Hopping Lon Lon
+                                                                                     // Ranch North Gate
     };
     s32 pad;
     s32 i;
-    Vec3s spawnPos;
 
     if ((gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_11 ||
          gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_12 ||
          gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_13 ||
          gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_15) &&
         (gSaveContext.respawnFlag == 0)) {
+        // Epona hopping over one of the Lon Lon Ranch fences
+        Vec3s spawnPos;
         Vec3s spawnPositions[] = {
-            { -2961, 313, 7700 },
-            { -1900, 313, 7015 },
-            { -4043, 313, 6933 },
-            { -2313, 313, 5990 },
+            // Note: The east and west positions are paired with the wrong entranceIndex. However, the subsequent
+            // cutscene repositions the horse will override these coordinates while the horse is still obstructed, so no
+            // visual glitch occurs.
+            { -2961, 313, 7700 }, // South
+            { -1900, 313, 7015 }, // East
+            { -4043, 313, 6933 }, // West
+            { -2313, 313, 5990 }, // North-East
         };
 
+        // South of Lon Lon player spawn
         if (gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_11) {
             spawnPos = spawnPositions[0];
+            // West of Lon Lon player spawn
         } else if (gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_12) {
             spawnPos = spawnPositions[1];
+            // East of Lon Lon player spawn
         } else if (gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_13) {
             spawnPos = spawnPositions[2];
+            // Lon Lon exit player spawn
         } else {
             spawnPos = spawnPositions[3];
         }
 
         player->rideActor = Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, spawnPos.x, spawnPos.y, spawnPos.z, 0,
-                                        player->actor.world.rot.y, 0, 7);
+                                        player->actor.world.rot.y, 0, HORSE_PTYPE_7);
         ASSERT(player->rideActor != NULL, "player->ride.actor != NULL", "../z_horse.c", 561);
 
         Actor_MountHorse(play, player, player->rideActor);
-        func_8002DE74(play, player);
+        Actor_RequestHorseCameraSetting(play, player);
         gSaveContext.save.info.horseData.sceneId = play->sceneId;
-    } else if ((play->sceneId == SCENE_LON_LON_RANCH) && (GET_EVENTINF_HORSES_STATE() == EVENTINF_HORSES_STATE_6) &&
-               !Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) && (DREG(1) == 0)) {
+    } else if ((play->sceneId == SCENE_LON_LON_RANCH) &&
+               (GET_EVENTINF_INGO_RACE_STATE() == INGO_RACE_STATE_TRAPPED_WIN_EPONA) &&
+               !(Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) || R_DEBUG_FORCE_EPONA_OBTAINED)) {
         player->rideActor =
-            Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, 894.0f, 0.0f, -2084.0f, 0, -0x7FFF, 0, 5);
+            Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, 894.0f, 0.0f, -2084.0f, 0, -0x7FFF, 0, HORSE_PTYPE_5);
         ASSERT(player->rideActor != NULL, "player->ride.actor != NULL", "../z_horse.c", 582);
 
         Actor_MountHorse(play, player, player->rideActor);
-        func_8002DE74(play, player);
+        Actor_RequestHorseCameraSetting(play, player);
         gSaveContext.save.info.horseData.sceneId = play->sceneId;
 
         if (play->sceneId == SCENE_GERUDOS_FORTRESS) {
             player->rideActor->room = -1;
         }
     } else {
-        for (i = 0; i < ARRAY_COUNT(D_8011F9B8); i++) {
-            if ((play->sceneId == D_8011F9B8[i].sceneId) &&
-                (((void)0, gSaveContext.save.cutsceneIndex) == D_8011F9B8[i].cutsceneIndex)) {
-                if (D_8011F9B8[i].type == 7) {
+        for (i = 0; i < ARRAY_COUNT(horseSpawns); i++) {
+            if ((play->sceneId == horseSpawns[i].sceneId) &&
+                (((void)0, gSaveContext.save.cutsceneIndex) == horseSpawns[i].cutsceneIndex)) {
+                if (horseSpawns[i].type == HORSE_PTYPE_7) {
                     if ((play->sceneId == SCENE_LON_LON_RANCH) &&
                         (((void)0, gSaveContext.save.cutsceneIndex) == 0xFFF1)) {
-                        D_8011F9B8[i].pos.x = player->actor.world.pos.x;
-                        D_8011F9B8[i].pos.y = player->actor.world.pos.y;
-                        D_8011F9B8[i].pos.z = player->actor.world.pos.z;
+                        horseSpawns[i].pos.x = player->actor.world.pos.x;
+                        horseSpawns[i].pos.y = player->actor.world.pos.y;
+                        horseSpawns[i].pos.z = player->actor.world.pos.z;
                     }
 
                     player->rideActor =
-                        Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, D_8011F9B8[i].pos.x, D_8011F9B8[i].pos.y,
-                                    D_8011F9B8[i].pos.z, 0, player->actor.world.rot.y, 0, D_8011F9B8[i].type);
+                        Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, horseSpawns[i].pos.x, horseSpawns[i].pos.y,
+                                    horseSpawns[i].pos.z, 0, player->actor.world.rot.y, 0, horseSpawns[i].type);
                     ASSERT(player->rideActor != NULL, "player->ride.actor != NULL", "../z_horse.c", 628);
 
                     Actor_MountHorse(play, player, player->rideActor);
-                    func_8002DE74(play, player);
-                } else if ((D_8011F9B8[i].type == 5) || (D_8011F9B8[i].type == 6) || (D_8011F9B8[i].type == 8)) {
-                    Vec3f sp54;
-                    s32 temp = 0;
-
-                    if (GET_EVENTINF_HORSES_HORSETYPE() != HORSE_EPONA && D_8011F9B8[i].type == 6) {
-                        temp = 0x8000;
+                    Actor_RequestHorseCameraSetting(play, player);
+                } else if ((horseSpawns[i].type == HORSE_PTYPE_5) || (horseSpawns[i].type == HORSE_PTYPE_6) ||
+                           (horseSpawns[i].type == HORSE_PTYPE_HORSEBACK_ARCHERY)) {
+                    Vec3f eye;
+                    s32 paramFlag = 0;
+
+                    if (GET_EVENTINF_INGO_RACE_HORSETYPE() != HORSE_EPONA && horseSpawns[i].type == HORSE_PTYPE_6) {
+                        // HORSE_HNI
+                        paramFlag = 0x8000;
                     }
 
                     player->rideActor =
-                        Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, D_8011F9B8[i].pos.x, D_8011F9B8[i].pos.y,
-                                    D_8011F9B8[i].pos.z, 0, D_8011F9B8[i].angle, 0, D_8011F9B8[i].type | temp);
+                        Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, horseSpawns[i].pos.x, horseSpawns[i].pos.y,
+                                    horseSpawns[i].pos.z, 0, horseSpawns[i].angle, 0, horseSpawns[i].type | paramFlag);
                     ASSERT(player->rideActor != NULL, "player->ride.actor != NULL", "../z_horse.c", 667);
 
-                    player->actor.world.pos.x = D_8011F9B8[i].pos.x;
-                    player->actor.world.pos.y = D_8011F9B8[i].pos.y;
-                    player->actor.world.pos.z = D_8011F9B8[i].pos.z;
+                    player->actor.world.pos.x = horseSpawns[i].pos.x;
+                    player->actor.world.pos.y = horseSpawns[i].pos.y;
+                    player->actor.world.pos.z = horseSpawns[i].pos.z;
                     player->actor.shape.rot.x = player->actor.shape.rot.z = 0;
-                    player->actor.shape.rot.y = D_8011F9B8[i].angle;
+                    player->actor.shape.rot.y = horseSpawns[i].angle;
 
                     Actor_MountHorse(play, player, player->rideActor);
-                    func_8002DE74(play, player);
+                    Actor_RequestHorseCameraSetting(play, player);
 
-                    sp54.x = player->actor.world.pos.x - 200.0f;
-                    sp54.y = player->actor.world.pos.y + 100.0f;
-                    sp54.z = player->actor.world.pos.z;
+                    eye.x = player->actor.world.pos.x - 200.0f;
+                    eye.y = player->actor.world.pos.y + 100.0f;
+                    eye.z = player->actor.world.pos.z;
 
-                    Play_SetCameraAtEye(play, play->activeCamId, &player->actor.world.pos, &sp54);
+                    Play_SetCameraAtEye(play, play->activeCamId, &player->actor.world.pos, &eye);
                 } else {
-                    Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, D_8011F9B8[i].pos.x, D_8011F9B8[i].pos.y,
-                                D_8011F9B8[i].pos.z, 0, D_8011F9B8[i].angle, 0, D_8011F9B8[i].type);
+                    Actor_Spawn(&play->actorCtx, play, ACTOR_EN_HORSE, horseSpawns[i].pos.x, horseSpawns[i].pos.y,
+                                horseSpawns[i].pos.z, 0, horseSpawns[i].angle, 0, horseSpawns[i].type);
                 }
                 break;
             }
@@ -242,41 +283,49 @@ void func_8006D684(PlayState* play, Player* player) {
     }
 }
 
-void func_8006DC68(PlayState* play, Player* player) {
+/**
+ * Initializes the player's horse, but only if required.
+ *
+ * This function should be called during `Play_Init`.
+ */
+void Horse_InitPlayerHorse(PlayState* play, Player* player) {
     if (LINK_IS_ADULT) {
-        if (!func_8006CFC0(gSaveContext.save.info.horseData.sceneId)) {
+        if (!Horse_CanSpawn(gSaveContext.save.info.horseData.sceneId)) {
             PRINTF(VT_COL(RED, WHITE));
             PRINTF(
                 T("Horse_Set_Check():%d セットスポットまずいです。\n", "Horse_Set_Check():%d set spot is no good.\n"),
                 gSaveContext.save.info.horseData.sceneId);
             PRINTF(VT_RST);
-            func_8006D074(play);
+            Horse_ResetHorseData(play);
         }
 
-        if (func_8006CFC0(play->sceneId)) {
+        if (Horse_CanSpawn(play->sceneId)) {
             if (IS_CUTSCENE_LAYER ||
+                // has hopped over one of the Lon-Lon Ranch fences
                 ((gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_11 ||
                   gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_12 ||
                   gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_13 ||
                   gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_15) &&
                  (gSaveContext.respawnFlag == 0)) ||
-                ((play->sceneId == SCENE_LON_LON_RANCH) && (GET_EVENTINF_HORSES_STATE() == EVENTINF_HORSES_STATE_6) &&
-                 !Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) && (DREG(1) == 0))) {
-                func_8006D684(play, player);
+                // trapped in Lon Lon Ranch
+                ((play->sceneId == SCENE_LON_LON_RANCH) &&
+                 (GET_EVENTINF_INGO_RACE_STATE() == INGO_RACE_STATE_TRAPPED_WIN_EPONA) &&
+                 !(Flags_GetEventChkInf(EVENTCHKINF_EPONA_OBTAINED) || R_DEBUG_FORCE_EPONA_OBTAINED))) {
+                Horse_SetupInCutscene(play, player);
             } else {
-                func_8006D0EC(play, player);
+                Horse_SetupInGameplay(play, player);
             }
         }
     }
 }
 
-void func_8006DD9C(Actor* actor, Vec3f* arg1, s16 arg2) {
-    s16 x = Math_Vec3f_Yaw(&actor->world.pos, arg1) - actor->world.rot.y;
+void Horse_RotateToPoint(Actor* actor, Vec3f* pos, s16 turnAmount) {
+    s16 x = Math_Vec3f_Yaw(&actor->world.pos, pos) - actor->world.rot.y;
 
-    if (x > arg2) {
-        actor->world.rot.y += arg2;
-    } else if (x < -arg2) {
-        actor->world.rot.y -= arg2;
+    if (x > turnAmount) {
+        actor->world.rot.y += turnAmount;
+    } else if (x < -turnAmount) {
+        actor->world.rot.y -= turnAmount;
     } else {
         actor->world.rot.y += x;
     }
diff --git a/src/code/z_message.c b/src/code/z_message.c
index 610396ff8..e17b5f3aa 100644
--- a/src/code/z_message.c
+++ b/src/code/z_message.c
@@ -3444,7 +3444,7 @@ void Message_DrawMain(PlayState* play, Gfx** p) {
                         if (msgCtx->disableWarpSongs || interfaceCtx->restrictions.warpSongs == 3) {
                             Message_StartTextbox(play, 0x88C, NULL); // "You can't warp here!"
                             play->msgCtx.ocarinaMode = OCARINA_MODE_04;
-                        } else if (GET_EVENTINF_HORSES_STATE() != EVENTINF_HORSES_STATE_1) {
+                        } else if (GET_EVENTINF_INGO_RACE_STATE() != INGO_RACE_STATE_HORSE_RENTAL_PERIOD) {
                             Message_StartTextbox(play, msgCtx->lastPlayedSong + 0x88D,
                                                  NULL); // "Warp to [place name]?"
                             play->msgCtx.ocarinaMode = OCARINA_MODE_01;
@@ -4247,7 +4247,7 @@ void Message_Update(PlayState* play) {
                         if (Message_ShouldAdvance(play)) {
                             PRINTF("OCARINA_MODE=%d -> ", play->msgCtx.ocarinaMode);
                             play->msgCtx.ocarinaMode = (msgCtx->choiceIndex == 0) ? OCARINA_MODE_02 : OCARINA_MODE_04;
-                            PRINTF("InRaceSeq=%d(%d) OCARINA_MODE=%d  -->  ", GET_EVENTINF_HORSES_STATE(), 1,
+                            PRINTF("InRaceSeq=%d(%d) OCARINA_MODE=%d  -->  ", GET_EVENTINF_INGO_RACE_STATE(), 1,
                                    play->msgCtx.ocarinaMode);
                             Message_CloseTextbox(play);
                             PRINTF("OCARINA_MODE=%d\n", play->msgCtx.ocarinaMode);
diff --git a/src/code/z_parameter.c b/src/code/z_parameter.c
index 7666b1ff0..65e92e33f 100644
--- a/src/code/z_parameter.c
+++ b/src/code/z_parameter.c
@@ -1,6 +1,7 @@
 #include "global.h"
 #include "terminal.h"
 #include "versions.h"
+#include "z64horse.h"
 #include "assets/textures/parameter_static/parameter_static.h"
 #include "assets/textures/do_action_static/do_action_static.h"
 #include "assets/textures/icon_item_static/icon_item_static.h"
@@ -790,7 +791,7 @@ void func_80083108(PlayState* play) {
                     gSaveContext.hudVisibilityMode = HUD_VISIBILITY_NO_CHANGE;
                     Interface_ChangeHudVisibilityMode(HUD_VISIBILITY_ALL);
                 }
-            } else if (GET_EVENTINF_HORSES_STATE() == EVENTINF_HORSES_STATE_1) {
+            } else if (GET_EVENTINF_INGO_RACE_STATE() == INGO_RACE_STATE_HORSE_RENTAL_PERIOD) {
                 if (player->stateFlags1 & PLAYER_STATE1_23) {
                     if ((gSaveContext.save.info.equips.buttonItems[0] != ITEM_NONE) &&
                         (gSaveContext.save.info.equips.buttonItems[0] != ITEM_BOW)) {
@@ -1387,7 +1388,7 @@ u8 Item_Give(PlayState* play, u8 item) {
         PRINTF(VT_RST);
 
         if (item == ITEM_MEDALLION_WATER) {
-            func_8006D0AC(play);
+            Horse_FixLakeHyliaPosition(play);
         }
 
         return ITEM_NONE;
@@ -3545,8 +3546,9 @@ void Interface_Draw(PlayState* play) {
                 if (INV_CONTENT(ITEM_TRADE_ADULT) == gSpoilingItems[svar1]) {
 #if OOT_VERSION >= NTSC_1_1
                     gSaveContext.eventInf[EVENTINF_HORSES_INDEX] &=
-                        (u16) ~(EVENTINF_HORSES_STATE_MASK | EVENTINF_HORSES_HORSETYPE_MASK | EVENTINF_HORSES_05_MASK |
-                                EVENTINF_HORSES_06_MASK | EVENTINF_HORSES_0F_MASK);
+                        (u16) ~(EVENTINF_INGO_RACE_STATE_MASK | EVENTINF_INGO_RACE_HORSETYPE_MASK |
+                                EVENTINF_INGO_RACE_LOST_ONCE_MASK | EVENTINF_INGO_RACE_SECOND_RACE_MASK |
+                                EVENTINF_INGO_RACE_0F_MASK);
                     PRINTF("EVENT_INF=%x\n", gSaveContext.eventInf[EVENTINF_HORSES_INDEX]);
 #endif
                     play->nextEntranceIndex = spoilingItemEntrances[svar1];
diff --git a/src/code/z_play.c b/src/code/z_play.c
index 29d692433..dc61e491c 100644
--- a/src/code/z_play.c
+++ b/src/code/z_play.c
@@ -489,7 +489,7 @@ void Play_Init(GameState* thisx) {
     Environment_PlaySceneSequence(this);
     gSaveContext.seqId = this->sceneSequences.seqId;
     gSaveContext.natureAmbienceId = this->sceneSequences.natureAmbienceId;
-    func_8002DF18(this, GET_PLAYER(this));
+    Actor_InitPlayerHorse(this, GET_PLAYER(this));
     AnimTaskQueue_Update(this, &this->animTaskQueue);
     gSaveContext.respawnFlag = 0;
 
@@ -1879,6 +1879,7 @@ void Play_LoadToLastEntrance(PlayState* this) {
                (gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_12) ||
                (gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_13) ||
                (gSaveContext.save.entranceIndex == ENTR_HYRULE_FIELD_15)) {
+        // Avoid re-triggering the hop over Lon Lon fence cutscenes
         this->nextEntranceIndex = ENTR_HYRULE_FIELD_6;
 #endif
     } else {