Change the frame where the audio plays at

src/Classes/Frame.gd

@@ -19,9 +19,15 @@ func get_duration_in_seconds(fps: float) -> float:
 
 func position_in_seconds(project: Project, start_from := 0) -> float:
 	var pos := 0.0
-	for i in range(start_from, project.frames.size()):
-		var frame := project.frames[i]
-		if frame == self:
-			break
-		pos += frame.get_duration_in_seconds(project.fps)
+	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)
+	else:
+		if start_from >= project.frames.size():
+			return -1.0
+		for i in range(start_from, index, -1):
+			var frame := project.frames[i]
+			pos -= frame.get_duration_in_seconds(project.fps)
 	return pos

src/Classes/Layers/AudioLayer.gd

@@ -7,7 +7,11 @@ var audio: AudioStream:
 	set(value):
 		audio = value
 		audio_changed.emit()
-var playback_position := 0.0  ## Measured in seconds.
+var playback_position := 0.0:  ## Measured in seconds.
+	get():
+		var frame := project.frames[playback_frame]
+		return frame.position_in_seconds(project)
+var playback_frame := 0
 
 
 func _init(_project: Project, _name := "") -> void:

src/UI/Timeline/CelButton.gd

@@ -407,7 +407,10 @@ func _is_playing_audio() -> void:
 	var frame_class := Global.current_project.frames[frame]
 	var layer_class := Global.current_project.layers[layer] as AudioLayer
 	var audio_length := layer_class.audio.get_length()
-	if frame_class.position_in_seconds(Global.current_project) < audio_length:
+	var frame_pos := frame_class.position_in_seconds(
+		Global.current_project, layer_class.playback_frame
+	)
+	if frame_pos >= 0 and frame_pos < audio_length:
 		cel_texture.texture = preload("res://assets/graphics/misc/musical_note.png")
 	else:
 		cel_texture.texture = null

src/UI/Timeline/LayerButton.gd

@@ -67,8 +67,10 @@ func _ready() -> void:
 
 func _on_cel_switched() -> void:
 	z_index = 1 if button_pressed else 0
-	if not animation_running or Global.current_project.current_frame == 0:
-		_play_audio()
+	var layer := Global.current_project.layers[layer_index]
+	if layer is AudioLayer:
+		if not animation_running or Global.current_project.current_frame == layer.playback_frame:
+			_play_audio()
 
 
 func _on_animation_started(_dir: bool) -> void:
@@ -85,13 +87,13 @@ func _on_animation_finished() -> void:
 func _play_audio() -> void:
 	if not is_instance_valid(audio_player):
 		return
-	var layer := Global.current_project.layers[layer_index]
+	var layer := Global.current_project.layers[layer_index] as AudioLayer
 	if not layer.visible:
 		return
 	var audio_length := audio_player.stream.get_length()
 	var frame := Global.current_project.frames[Global.current_project.current_frame]
-	var frame_pos := frame.position_in_seconds(Global.current_project)
-	if frame_pos < audio_length:
+	var frame_pos := frame.position_in_seconds(Global.current_project, layer.playback_frame)
+	if frame_pos >= 0 and frame_pos < audio_length:
 		audio_player.play(frame_pos)
 	else:
 		audio_player.stop()

src/UI/Timeline/LayerProperties.gd

@@ -4,9 +4,11 @@ signal layer_property_changed
 
 var layer_indices: PackedInt32Array
 
+@onready var grid_container: GridContainer = $GridContainer
 @onready var name_line_edit := $GridContainer/NameLineEdit as LineEdit
 @onready var opacity_slider := $GridContainer/OpacitySlider as ValueSlider
 @onready var blend_modes_button := $GridContainer/BlendModeOptionButton as OptionButton
+@onready var play_at_frame_slider := $GridContainer/PlayAtFrameSlider as ValueSlider
 @onready var user_data_text_edit := $GridContainer/UserDataTextEdit as TextEdit
 @onready var tileset_option_button := $GridContainer/TilesetOptionButton as OptionButton
 
@@ -23,8 +25,15 @@ func _on_visibility_changed() -> void:
 		opacity_slider.value = first_layer.opacity * 100.0
 		var blend_mode_index := blend_modes_button.get_item_index(first_layer.blend_mode)
 		blend_modes_button.selected = blend_mode_index
+		if first_layer is AudioLayer:
+			play_at_frame_slider.value = first_layer.playback_frame + 1
+		play_at_frame_slider.max_value = project.frames.size()
 		user_data_text_edit.text = first_layer.user_data
+		for child in grid_container.get_children():
+			if not child.is_in_group(&"AllLayers"):
+				child.visible = first_layer is not AudioLayer
 		get_tree().set_group(&"TilemapLayers", "visible", first_layer is LayerTileMap)
+		get_tree().set_group(&"AudioLayers", "visible", first_layer is AudioLayer)
 		tileset_option_button.clear()
 		if first_layer is LayerTileMap:
 			for i in project.tilesets.size():
@@ -149,3 +158,12 @@ func _on_tileset_option_button_item_selected(index: int) -> void:
 	project.undo_redo.add_undo_method(Global.canvas.draw_layers)
 	project.undo_redo.add_undo_method(func(): Global.cel_switched.emit())
 	project.undo_redo.commit_action()
+
+
+func _on_play_at_frame_slider_value_changed(value: float) -> void:
+	if layer_indices.size() == 0:
+		return
+	for layer_index in layer_indices:
+		var layer := Global.current_project.layers[layer_index]
+		if layer is AudioLayer:
+			layer.playback_frame = value - 1

src/UI/Timeline/LayerProperties.tscn

@@ -5,22 +5,22 @@
 
 [node name="LayerProperties" type="AcceptDialog"]
 title = "Layer properties"
-size = Vector2i(300, 208)
+size = Vector2i(300, 235)
 script = ExtResource("1_54q1t")
 
 [node name="GridContainer" type="GridContainer" parent="."]
 offset_left = 8.0
 offset_top = 8.0
 offset_right = 292.0
-offset_bottom = 159.0
+offset_bottom = 186.0
 columns = 2
 
-[node name="NameLabel" type="Label" parent="GridContainer"]
+[node name="NameLabel" type="Label" parent="GridContainer" groups=["AllLayers"]]
 layout_mode = 2
 size_flags_horizontal = 3
 text = "Name:"
 
-[node name="NameLineEdit" type="LineEdit" parent="GridContainer"]
+[node name="NameLineEdit" type="LineEdit" parent="GridContainer" groups=["AllLayers"]]
 layout_mode = 2
 size_flags_horizontal = 3
 
@@ -52,13 +52,32 @@ layout_mode = 2
 size_flags_horizontal = 3
 mouse_default_cursor_shape = 2
 
-[node name="UserDataLabel" type="Label" parent="GridContainer"]
+[node name="PlayAtFrameLabel" type="Label" parent="GridContainer" groups=["AudioLayers"]]
+layout_mode = 2
+text = "Play at frame:"
+
+[node name="PlayAtFrameSlider" type="TextureProgressBar" parent="GridContainer" groups=["AudioLayers"]]
+layout_mode = 2
+focus_mode = 2
+mouse_default_cursor_shape = 2
+theme_type_variation = &"ValueSlider"
+min_value = 1.0
+value = 1.0
+allow_greater = true
+nine_patch_stretch = true
+stretch_margin_left = 3
+stretch_margin_top = 3
+stretch_margin_right = 3
+stretch_margin_bottom = 3
+script = ExtResource("2_bwpwc")
+
+[node name="UserDataLabel" type="Label" parent="GridContainer" groups=["AllLayers"]]
 layout_mode = 2
 size_flags_horizontal = 3
 size_flags_vertical = 0
 text = "User data:"
 
-[node name="UserDataTextEdit" type="TextEdit" parent="GridContainer"]
+[node name="UserDataTextEdit" type="TextEdit" parent="GridContainer" groups=["AllLayers"]]
 layout_mode = 2
 size_flags_horizontal = 3
 scroll_fit_content_height = true
@@ -77,5 +96,6 @@ mouse_default_cursor_shape = 2
 [connection signal="text_changed" from="GridContainer/NameLineEdit" to="." method="_on_name_line_edit_text_changed"]
 [connection signal="value_changed" from="GridContainer/OpacitySlider" to="." method="_on_opacity_slider_value_changed"]
 [connection signal="item_selected" from="GridContainer/BlendModeOptionButton" to="." method="_on_blend_mode_option_button_item_selected"]
+[connection signal="value_changed" from="GridContainer/PlayAtFrameSlider" to="." method="_on_play_at_frame_slider_value_changed"]
 [connection signal="text_changed" from="GridContainer/UserDataTextEdit" to="." method="_on_user_data_text_edit_text_changed"]
 [connection signal="item_selected" from="GridContainer/TilesetOptionButton" to="." method="_on_tileset_option_button_item_selected"]