From 35ec39d188701194b79ed5bfbcc885f1d8e4eb05 Mon Sep 17 00:00:00 2001
From: Ryan Dwyer <ryandwyer1@gmail.com>
Date: Sun, 9 Jan 2022 10:54:15 +1000
Subject: [PATCH] Attempt to decompile mpChooseTrack

---
 src/game/game_176080.c             |  6 +-
 src/game/mplayer/mplayer.c         | 93 +++++++++++++++++++++++++++++-
 src/include/game/mplayer/mplayer.h |  2 +-
 src/include/types.h                |  2 +-
 4 files changed, 95 insertions(+), 8 deletions(-)

diff --git a/src/game/game_176080.c b/src/game/game_176080.c
index d0c36639f..8dd8c3057 100644
--- a/src/game/game_176080.c
+++ b/src/game/game_176080.c
@@ -611,7 +611,7 @@ s32 stageGetPrimaryTrack(s32 stagenum)
 	s32 i;
 
 	if (g_Vars.normmplayerisrunning) {
-		return mpChooseRandomTrack();
+		return mpChooseTrack();
 	}
 
 	i = 0;
@@ -619,7 +619,7 @@ s32 stageGetPrimaryTrack(s32 stagenum)
 	while (g_StageTracks[i].stagenum) {
 		if (g_StageTracks[i].stagenum == stagenum) {
 			if (g_StageTracks[i].primarytrack == -1) {
-				return mpChooseRandomTrack();
+				return mpChooseTrack();
 			}
 
 			return g_StageTracks[i].primarytrack;
@@ -628,7 +628,7 @@ s32 stageGetPrimaryTrack(s32 stagenum)
 		i++;
 	}
 
-	return mpChooseRandomTrack();
+	return mpChooseTrack();
 }
 
 s32 stageGetAmbientTrack(s32 stagenum)
diff --git a/src/game/mplayer/mplayer.c b/src/game/mplayer/mplayer.c
index 6babd1cc6..edf7033d8 100644
--- a/src/game/mplayer/mplayer.c
+++ b/src/game/mplayer/mplayer.c
@@ -276,7 +276,7 @@ void mpInit(void)
 			}
 		}
 
-		g_MpLockInfo.unk04 = 0xffffffff;
+		g_MpLockInfo.unk04 = -1;
 	}
 
 	// Assign aibot commands to active menu slots
@@ -7499,7 +7499,7 @@ s32 mpGetCurrentTrackSlotNum(void)
 
 #if VERSION >= VERSION_PAL_FINAL
 GLOBAL_ASM(
-glabel mpChooseRandomTrack
+glabel mpChooseTrack
 /*  f18d564:	27bdffc8 */ 	addiu	$sp,$sp,-56
 /*  f18d568:	afbf0034 */ 	sw	$ra,0x34($sp)
 /*  f18d56c:	afb60030 */ 	sw	$s6,0x30($sp)
@@ -7713,7 +7713,7 @@ glabel mpChooseRandomTrack
 );
 #else
 GLOBAL_ASM(
-glabel mpChooseRandomTrack
+glabel mpChooseTrack
 /*  f18c4c0:	27bdffc8 */ 	addiu	$sp,$sp,-56
 /*  f18c4c4:	afbf0034 */ 	sw	$ra,0x34($sp)
 /*  f18c4c8:	afb60030 */ 	sw	$s6,0x30($sp)
@@ -7917,6 +7917,93 @@ glabel mpChooseRandomTrack
 );
 #endif
 
+// Mismatch: goal uses shifting to calculate the offset into g_MpTracks
+// while the below uses multu.
+//s32 mpChooseTrack(void)
+//{
+//	s32 i;
+//	s32 tracknum;
+//
+//	if (mpGetUsingMultipleTunes()) {
+//		s32 numunlocked = mpGetNumUnlockedTracks();
+//		s32 numselected = 0;
+//
+//		// 508
+//		for (i = 0; i < numunlocked; i++) {
+//			if (mpIsMultiTrackSlotEnabled(i)) {
+//				numselected++;
+//			}
+//		}
+//
+//		// 528
+//		if (numselected == 0) {
+//			do {
+//				tracknum = mpGetTrackNumAtSlotIndex(random() % numunlocked);
+//			} while (tracknum == g_MpLockInfo.unk04);
+//
+//			// 568
+//			g_MpLockInfo.unk04 = tracknum;
+//			g_MusicLife60 = g_MpTracks[tracknum].duration * PALDOWN(60);
+//
+//			return g_MpTracks[tracknum].musicnum;
+//		}
+//
+//		// 5a4
+//		do {
+//			s32 selectionindex = random() % numselected;
+//			s32 selectioncount = 0;
+//			tracknum = -1; // s3
+//
+//			// 5d8
+//			for (i = 0; i < numunlocked; i++) {
+//				if (mpIsMultiTrackSlotEnabled(i)) {
+//					if (selectionindex == selectioncount) {
+//						tracknum = i;
+//					}
+//
+//					selectioncount++;
+//				}
+//			}
+//
+//			// 608
+//			if (tracknum == -1) {
+//				g_MusicLife60 = g_MpTracks[0].duration * PALDOWN(60);
+//				return g_MpTracks[0].musicnum;
+//			}
+//
+//			// 634
+//			tracknum = mpGetTrackNumAtSlotIndex(tracknum);
+//		} while (numselected > 1 && tracknum == g_MpLockInfo.unk04);
+//
+//		// 654
+//		g_MpLockInfo.unk04 = tracknum;
+//		g_MusicLife60 = g_MpTracks[tracknum].duration * PALDOWN(60);
+//
+//		return g_MpTracks[tracknum].musicnum;
+//	}
+//
+//	// 690
+//	tracknum = mpGetCurrentTrackSlotNum();
+//
+//	if (tracknum < 0) {
+//		s32 numunlocked = mpGetNumUnlockedTracks();
+//
+//		do {
+//			tracknum = mpGetTrackNumAtSlotIndex(random() % numunlocked);
+//		} while (tracknum == g_MpLockInfo.unk04);
+//
+//		g_MpLockInfo.unk04 = tracknum;
+//		g_MusicLife60 = g_MpTracks[tracknum].duration * PALDOWN(60);
+//		return g_MpTracks[tracknum].musicnum;
+//	}
+//
+//	tracknum = mpGetTrackNumAtSlotIndex(tracknum);
+//	g_MpLockInfo.unk04 = tracknum;
+//	g_MusicLife60 = g_MpTracks[g_MpLockInfo.unk04].duration * PALDOWN(60);
+//
+//	return g_MpTracks[tracknum].musicnum;
+//}
+
 struct mpchrconfig *mpGetChrConfigBySlotNum(s32 slot)
 {
 	s32 count = 0;
diff --git a/src/include/game/mplayer/mplayer.h b/src/include/game/mplayer/mplayer.h
index f039adac9..e6c9741d0 100644
--- a/src/include/game/mplayer/mplayer.h
+++ b/src/include/game/mplayer/mplayer.h
@@ -79,7 +79,7 @@ void mpDisableAllMultiTracks(void);
 void mpRandomiseMultiTracks(void);
 void mpSetTrackToRandom(void);
 s32 mpGetCurrentTrackSlotNum(void);
-u32 mpChooseRandomTrack(void);
+s32 mpChooseTrack(void);
 struct mpchrconfig *mpGetChrConfigBySlotNum(s32 slot);
 s32 mpGetChrIndexBySlotNum(s32 slot);
 s32 mpGetNumChrs(void);
diff --git a/src/include/types.h b/src/include/types.h
index 5dfb4f3ed..1c1b012ac 100644
--- a/src/include/types.h
+++ b/src/include/types.h
@@ -6133,7 +6133,7 @@ struct mplockinfo {
 	s8 lastwinner;
 	s8 lastloser;
 	s8 unk03;
-	s32 unk04; // might not be part of struct
+	s32 unk04;
 };
 
 struct var8009da60 {