Added on_beat_hit and on_step_hit to MusicBeatScene

Closes #3

pyday_night_funkin/conductor.py

@@ -1,6 +1,16 @@
 
 import typing as t
 
+
+class BPMChangeEvent():
+	__slots__ = ("step_time", "song_time", "bpm")
+
+	def __init__(self, step_time: float, song_time: float, bpm: float) -> None:
+		self.step_time = step_time
+		self.song_time = song_time
+		self.bpm = bpm
+
+
 # The tiniest conductor
 class Conductor():
 	# https://ninjamuffin99.newgrounds.com/news/post/1124589
@@ -13,6 +23,7 @@ def __init__(self) -> None:
 		self.beat_duration = None
 		self.step_duration = None
 		self.song_position = 0.0
+		self._bpm_changes: t.List[BPMChangeEvent] = []
 
 	@property
 	def bpm(self) -> t.Optional[float]:
@@ -30,3 +41,31 @@ def bpm(self, new_bpm: float) -> None:
 		# step is just a quarter beat duration
 		# idk about music this probably has a reason
 		self.step_duration = self.beat_duration / 4.0
+
+	@property
+	def last_bpm_change(self) -> BPMChangeEvent:
+		r = BPMChangeEvent(0.0, 0.0, 0.0)
+		# NOTE: pretty intensive loop, could be kept track of way easier by
+		# adding a song_position property
+		for change in self._bpm_changes:
+			if self.song_position >= change.song_time:
+				r = change
+			else:
+				break
+		return r
+
+	def load_bpm_changes(self, song_data) -> None:
+		bpm_changes = []
+		cur_bpm = song_data["song"]["bpm"]
+		total_steps = 0
+		total_pos = 0.0
+		for section in song_data["song"]["notes"]:
+			if "changeBPM" in section and section["changeBPM"] and section["bpm"] != cur_bpm:
+				cur_bpm = section["bpm"]
+				bpm_changes.append(BPMChangeEvent(total_steps, total_pos, cur_bpm))
+
+			step_delta = section["lengthInSteps"]
+			total_steps += step_delta
+			total_pos += (15000.0 / cur_bpm) * step_delta
+
+		self._bpm_changes = bpm_changes

pyday_night_funkin/graphics/pnf_sprite.py

@@ -255,8 +255,6 @@ def __init__(
 		self.current_animation: t.Optional[str] = None
 		self.camera = camera
 
-		self.asdfdebug = False
-
 		self._x = x
 		self._y = y
 

pyday_night_funkin/scenes/in_game.py

@@ -85,6 +85,7 @@ def load_song(self) -> t.Dict:
 			self.voice_player.queue(voices)
 
 		self.conductor.bpm = song_data["song"]["bpm"]
+		self.conductor.load_bpm_changes(song_data)
 		self.note_handler.feed_song_data(song_data)
 
 	def start_song(self) -> None:
@@ -124,3 +125,7 @@ def process_input(self, dt: float) -> None:
 		handled here.
 		"""
 		pass
+
+	def on_beat_hit(self) -> None:
+		super().on_beat_hit()
+		logger.debug("beat hit")

pyday_night_funkin/scenes/music_beat.py

@@ -1,7 +1,10 @@
 
+from math import floor
+
 from pyday_night_funkin.conductor import Conductor
 from pyday_night_funkin.scenes._base import BaseScene
 
+
 class MusicBeatScene(BaseScene):
 
 	def __init__(self, *args, **kwargs) -> None:
@@ -14,5 +17,20 @@ def __init__(self, *args, **kwargs) -> None:
 	def update(self, dt: float) -> None:
 		super().update(dt)
 
-		# TODO: beat hit stuff
+		old_step = self.cur_step
+
+		lc = self.conductor.last_bpm_change
+		self.cur_step = lc.step_time + floor(
+			(self.conductor.song_position - lc.song_time) / self.conductor.step_duration
+		)
+		self.cur_beat = floor(self.cur_step / 4)
+
+		if old_step != self.cur_step:
+			self.on_step_hit()
+
+	def on_beat_hit(self) -> None:
+		pass
 
+	def on_step_hit(self) -> None:
+		if self.cur_step % 4 == 0:
+			self.on_beat_hit()