Speed up BGM playback by storing XA locations on startup

include/sound.h

@@ -65,8 +65,11 @@ uint32_t    sound_upload_vag(const uint32_t *data, uint32_t size);
 void        sound_play_vag(SoundEffect sfx, uint8_t loops);
 
 uint32_t sound_get_cd_status(void);
+CdlLOC   sound_find_xa(const char *filename);
 void     sound_play_xa(const char *filename, int double_speed,
                        uint8_t channel, uint32_t loopback_sector);
+void     sound_play_xa_immediate(CdlLOC *loc, int double_speed,
+                                 uint8_t channel, uint32_t loopback_sector);
 void     sound_stop_xa(void);
 int      sound_xa_requested_play();
 void     sound_xa_set_channel(uint8_t channel);
@@ -102,6 +105,7 @@ typedef struct {
     uint16_t stop_sector;
 } BGMTableEntry;
 
+void                sound_bgm_init();
 void                sound_bgm_play(BGMOption);
 const BGMTableEntry *sound_bgm_get_data(BGMOption);
 void                sound_bgm_check_stop(BGMOption);

src/main.c

@@ -56,8 +56,8 @@ main(void)
 {
     // Engine initialization
     setup_context();
-    sound_init();
     CdInit();
+    sound_init();
     pad_init();
     timer_init();
     fastalloc_init();

src/sound.c

@@ -65,6 +65,8 @@ sound_init(void)
     sound_reset_mem();
     _sound_reset_channels();
     sound_xa_set_volume(XA_DEFAULT_VOLUME);
+
+    sound_bgm_init();
 }
 
 void
@@ -163,28 +165,47 @@ sound_play_vag(SoundEffect sfx, uint8_t loops)
 
 void _xacd_event_callback(CdlIntrResult, uint8_t *);
 
+CdlLOC
+sound_find_xa(const char *filename)
+{
+    CdlFILE file = { 0 };
+    if(!CdSearchFile(&file, filename)) {
+        printf("WARNING: Could not find .XA file %s.\n", filename);
+        return (CdlLOC){ 0 };
+    }
+    return file.pos;
+}
+
 void
 sound_play_xa(const char *filename, int double_speed,
               uint8_t channel, uint32_t loopback_sector)
 {
-    CdlFILE file;
+    sound_stop_xa();
+    CdlLOC loc = sound_find_xa(filename);
+    /* int sectorn = CdPosToInt(&loc); */
+    /* int numsectors = (file.size + 2047) / 2048; */
+    /* printf("%s: Sector %d (size: %d => %d sectors).\n", */
+    /*        filename, sectorn, file.size, numsectors); */
+    sound_play_xa_immediate(&loc, double_speed, channel, loopback_sector);
+}
+
+void
+sound_play_xa_immediate(
+    CdlLOC *loc, int double_speed,
+    uint8_t channel, uint32_t loopback_sector)
+{
     CdlFILTER filter;
 
     // Stop sound if playing. We'll need the CD right now
     sound_stop_xa();
-    
-    if(!CdSearchFile(&file, filename)) {
-        printf("Could not find .XA file %s.\n", filename);
-        return;
-    }
 
-    int sectorn = CdPosToInt(&file.pos);
-    int numsectors = (file.size + 2047) / 2048;
-    printf("%s: Sector %d (size: %d => %d sectors).\n",
-           filename, sectorn, file.size, numsectors);
+    /* int sectorn = CdPosToInt(&file.pos); */
+    /* int numsectors = (file.size + 2047) / 2048; */
+    /* printf("%s: Sector %d (size: %d => %d sectors).\n", */
+    /*        filename, sectorn, file.size, numsectors); */
 
     // Save current file location
-    _xa_loc = file.pos;
+    _xa_loc = *loc;
 
     // Hook .XA callback for auto stop/loop
     cd_set_callbacks(PLAYBACK_XA);

src/sound_bgmtable.c

@@ -24,11 +24,22 @@ const BGMTableEntry bgm_table[] = {
     {"\\BGM\\BGM003.XA;1",   1, 2830, 0}, // EZ
 };
 
+static CdlLOC bgm_table_locs[BGM_NUM_SONGS];
+
+void
+sound_bgm_init()
+{
+    // Find location of all songs on bgm table and store them
+    for(int i = 0; i < BGM_NUM_SONGS; i++) {
+        bgm_table_locs[i] = sound_find_xa(bgm_table[i].filename);
+    }
+}
+
 void
 sound_bgm_play(BGMOption t)
 {
-    sound_play_xa(
-        bgm_table[t].filename,
+    sound_play_xa_immediate(
+        &bgm_table_locs[t],
         0,
         bgm_table[t].channel,
         bgm_table[t].loopback_sector);