1 files changed, 83 insertions, 0 deletions
diff --git a/src/music.cpp b/src/music.cpp
new file mode 100644
index 0000000..a687d35
--- /dev/null
+++ b/src/music.cpp
@@ -0,0 +1,83 @@
+#include <game.h>
+
+struct HijackedStream {
+	//const char *original;
+	//const char *originalFast;
+	u32 stringOffset;
+	u32 stringOffsetFast;
+	u8 originalID;
+};
+
+struct Hijacker {
+	HijackedStream stream[2];
+	u8 currentStream;
+	u8 currentCustomTheme;
+};
+
+
+// Offsets are from the start of the INFO block, not the start of the brsar.
+// INFO begins at 0x212C0, so that has to be subtracted from absolute offsets
+// within the brsar.
+
+#define _I(offs) ((offs)-0x212C0)
+
+Hijacker Hijackers[2] = {
+	{
+		{
+			{/*"athletic_lr.n.32.brstm", "athletic_fast_lr.n.32.brstm",*/ _I(0x4A8F8), _I(0x4A938), 4},
+			{/*"BGM_SIRO.32.brstm", "BGM_SIRO_fast.32.brstm",*/ _I(0x4B2E8), _I(0x4B320), 10}
+		},
+		0, 0
+	},
+
+	{
+		{
+			{/*"STRM_BGM_CHIJOU.brstm", "STRM_BGM_CHIJOU_FAST.brstm",*/ _I(0x4A83C), _I(0x4A8B4), 1},
+			{/*"STRM_BGM_CHIKA.brstm", "STRM_BGM_CHIKA_FAST.brstm",*/ _I(0x4A878), _I(0x4A780), 2},
+		},
+		0, 0
+	}
+};
+
+extern void *SoundRelatedClass;
+inline char *BrsarInfoOffset(u32 offset) {
+	return (char*)(*(u32*)(((u32)SoundRelatedClass) + 0x5CC)) + offset;
+}
+
+extern "C" u8 after_course_getMusicForZone(u8 realThemeID) {
+	if (realThemeID < 100)
+		return realThemeID;
+
+	// drums get to use type 1
+	int hjIndex = (realThemeID >= 200) ? 1 : 0;
+
+	Hijacker *hj = &Hijackers[hjIndex];
+
+	// do we already have this theme in this slot?
+	// if so, don't switch streams
+	// if we do, NSMBW will think it's a different song, and restart it ...
+	// but if it's just an area transition where both areas are using the same
+	// song, we don't want that
+	if (hj->currentCustomTheme == realThemeID)
+		return hj->stream[hj->currentStream].originalID;
+
+	// which one do we use this time...?
+	int toUse = (hj->currentStream + 1) & 1;
+
+	hj->currentStream = toUse;
+	hj->currentCustomTheme = realThemeID;
+
+	// write the stream's info
+	HijackedStream *stream = &hj->stream[hj->currentStream];
+
+	sprintf(BrsarInfoOffset(stream->stringOffset), "stream/theme%03d.brstm", realThemeID);
+	sprintf(BrsarInfoOffset(stream->stringOffsetFast), "stream/theme%03d_fast.brstm", realThemeID);
+
+	// done!
+
+	return stream->originalID;
+}
+
+
+
+