From a150b66fe7d5f5d8341b3a5c529ce3a6a39ba9d4 Mon Sep 17 00:00:00 2001
From: Emmanouil Papadeas <35376950+OverloadedOrama@users.noreply.github.com>
Date: Sat, 14 Dec 2024 00:25:57 +0200
Subject: [PATCH] Some code changes to allow for potential negative frames
 placement for audio

This woud allow audio to be placed in negative frames, which essentially means that audio would start before the first frame. This is not yet supported, however, because I don't know how to make it work with FFMPEG.
---
 src/Classes/Frame.gd             | 7 +++++--
 src/Classes/Layers/AudioLayer.gd | 9 +++++++--
 src/UI/Timeline/LayerButton.gd   | 8 ++++++--
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/Classes/Frame.gd b/src/Classes/Frame.gd
index 21ef3ff9b..ec5358ab2 100644
--- a/src/Classes/Frame.gd
+++ b/src/Classes/Frame.gd
@@ -22,8 +22,11 @@ func position_in_seconds(project: Project, start_from := 0) -> float:
 	var index := project.frames.find(self)
 	if index > start_from:
 		for i in range(start_from, index):
-			var frame := project.frames[i]
-			pos += frame.get_duration_in_seconds(project.fps)
+			if i >= 0:
+				var frame := project.frames[i]
+				pos += frame.get_duration_in_seconds(project.fps)
+			else:
+				pos += 1.0 / project.fps
 	else:
 		if start_from >= project.frames.size():
 			return -1.0
diff --git a/src/Classes/Layers/AudioLayer.gd b/src/Classes/Layers/AudioLayer.gd
index ca22fb086..7dd2f5f27 100644
--- a/src/Classes/Layers/AudioLayer.gd
+++ b/src/Classes/Layers/AudioLayer.gd
@@ -13,8 +13,13 @@ var audio: AudioStream:  ## The audio stream of the layer.
 		audio_changed.emit()
 var playback_position := 0.0:  ## The time in seconds where the audio stream starts playing.
 	get():
-		var frame := project.frames[playback_frame]
-		return frame.position_in_seconds(project)
+		if playback_frame >= 0:
+			var frame := project.frames[playback_frame]
+			return frame.position_in_seconds(project)
+		var pos := 0.0
+		for i in absi(playback_frame):
+			pos -= 1.0 / project.fps
+		return pos
 var playback_frame := 0:  ## The frame where the audio stream starts playing.
 	set(value):
 		playback_frame = value
diff --git a/src/UI/Timeline/LayerButton.gd b/src/UI/Timeline/LayerButton.gd
index ecd09324a..fbb564bd5 100644
--- a/src/UI/Timeline/LayerButton.gd
+++ b/src/UI/Timeline/LayerButton.gd
@@ -76,7 +76,11 @@ func _on_cel_switched() -> void:
 			audio_player.stop()
 			return
 		if animation_running:
-			if Global.current_project.current_frame == layer.playback_frame:
+			var current_frame := Global.current_project.current_frame
+			if (
+				current_frame == layer.playback_frame
+				or (current_frame == 0 and layer.playback_frame < 0)
+			):
 				_play_audio(false)
 		else:
 			_play_audio(true)
@@ -90,7 +94,7 @@ func _on_animation_started(_dir: bool) -> void:
 func _on_animation_looped() -> void:
 	var layer := Global.current_project.layers[layer_index]
 	if layer is AudioLayer:
-		if layer.playback_frame != 0 or not layer.is_visible_in_hierarchy():
+		if layer.playback_frame > 0 or not layer.is_visible_in_hierarchy():
 			if is_instance_valid(audio_player):
 				audio_player.stop()