New PlayBGM param: StartPosition

This parameter lets you choose the sample point where the music should start playing. It can be used in PlayBGM SCTRL and lua function.

src/bytecode.go

@@ -7538,14 +7538,15 @@ const (
 	playBgm_loop
 	playBgm_loopstart
 	playBgm_loopend
+	playBgm_startposition
 	playBgm_redirectid
 )
 
 func (sc playBgm) Run(c *Char, _ []int32) bool {
 	crun := c
 	var b bool
 	var bgm string
-	var loop, volume, loopstart, loopend int = 1, 100, 0, 0
+	var loop, volume, loopstart, loopend, startposition int = 1, 100, 0, 0, 0
 	StateControllerBase(sc).run(c, func(id byte, exp []BytecodeExp) bool {
 		switch id {
 		case playBgm_bgm:
@@ -7565,6 +7566,8 @@ func (sc playBgm) Run(c *Char, _ []int32) bool {
 			loopstart = int(exp[0].evalI(c))
 		case playBgm_loopend:
 			loopend = int(exp[0].evalI(c))
+		case playBgm_startposition:
+			startposition = int(exp[0].evalI(c))
 		case playBgm_redirectid:
 			if rid := sys.playerID(exp[0].evalI(c)); rid != nil {
 				crun = rid
@@ -7575,7 +7578,7 @@ func (sc playBgm) Run(c *Char, _ []int32) bool {
 		return true
 	})
 	if b {
-		sys.bgm.Open(bgm, loop, volume, loopstart, loopend)
+		sys.bgm.Open(bgm, loop, volume, loopstart, loopend, startposition)
 		sys.playBgmFlg = true
 	}
 	return false

src/compiler_functions.go

@@ -4147,6 +4147,10 @@ func (c *Compiler) playBgm(is IniSection, sc *StateControllerBase, _ int8) (Stat
 			playBgm_loopend, VT_Int, 1, false); err != nil {
 			return err
 		}
+		if err := c.paramValue(is, sc, "startposition",
+			playBgm_startposition, VT_Int, 1, false); err != nil {
+			return err
+		}
 		return nil
 	})
 	return *ret, err

src/script.go

@@ -1040,7 +1040,7 @@ func systemScriptInit(l *lua.LState) {
 				l.Push(lua.LNumber(winp))
 				l.Push(tbl)
 				if sys.playBgmFlg {
-					sys.bgm.Open("", 1, 100, 0, 0)
+					sys.bgm.Open("", 1, 100, 0, 0, 0)
 					sys.playBgmFlg = false
 				}
 				sys.clearAllSound()
@@ -1536,7 +1536,7 @@ func systemScriptInit(l *lua.LState) {
 		return 0
 	})
 	luaRegister(l, "playBGM", func(l *lua.LState) int {
-		var loop, volume, loopstart, loopend int = 1, 100, 0, 0
+		var loop, volume, loopstart, loopend, startposition int = 1, 100, 0, 0, 0
 		if l.GetTop() >= 2 {
 			loop = int(numArg(l, 2))
 		}
@@ -1549,7 +1549,10 @@ func systemScriptInit(l *lua.LState) {
 		if l.GetTop() >= 5 && numArg(l, 5) > 1 {
 			loopend = int(numArg(l, 5))
 		}
-		sys.bgm.Open(strArg(l, 1), loop, volume, loopstart, loopend)
+		if l.GetTop() >= 6 && numArg(l, 6) > 1 {
+			startposition = int(numArg(l, 6))
+		}
+		sys.bgm.Open(strArg(l, 1), loop, volume, loopstart, loopend, startposition)
 		return 0
 	})
 	luaRegister(l, "playerBufReset", func(*lua.LState) int {

src/sound.go

@@ -156,7 +156,7 @@ func newBgm() *Bgm {
 	return &Bgm{}
 }
 
-func (bgm *Bgm) Open(filename string, loop, bgmVolume, bgmLoopStart, bgmLoopEnd int) {
+func (bgm *Bgm) Open(filename string, loop, bgmVolume, bgmLoopStart, bgmLoopEnd, startPosition int) {
 	bgm.filename = filename
 	bgm.loop = loop
 	bgm.bgmVolume = bgmVolume
@@ -211,6 +211,7 @@ func (bgm *Bgm) Open(filename string, loop, bgmVolume, bgmLoopStart, bgmLoopEnd
 	resampler := beep.Resample(audioResampleQuality, format.SampleRate, audioFrequency, bgm.volctrl)
 	bgm.ctrl = &beep.Ctrl{Streamer: resampler}
 	bgm.UpdateVolume()
+	bgm.streamer.Seek(startPosition)
 	speaker.Play(bgm.ctrl)
 }
 

src/system.go

@@ -1852,7 +1852,7 @@ func (s *System) fight() (reload bool) {
 
 	//default bgm playback, used only in Quick VS or if externalized Lua implementaion is disabled
 	if s.round == 1 && (s.gameMode == "" || len(sys.commonLua) == 0) {
-		s.bgm.Open(s.stage.bgmusic, 1, int(s.stage.bgmvolume), int(s.stage.bgmloopstart), int(s.stage.bgmloopend))
+		s.bgm.Open(s.stage.bgmusic, 1, int(s.stage.bgmvolume), int(s.stage.bgmloopstart), int(s.stage.bgmloopend), 0)
 	}
 
 	oldWins, oldDraws := s.wins, s.draws