Fix background transitions

Should fix dialogic-godot#2038 and a problem reported on discord

addons/dialogic/Modules/Background/Transitions/class_dialogic_background_transition.gd

@@ -51,6 +51,6 @@ func tween_shader_progress(progress_parameter:="progress") -> PropertyTweener:
 
 	bg_holder.material.set_shader_parameter("progress", 0.0)
 	var tween := create_tween()
-	var tweener := tween.tween_property(bg_holder, "material:shader_parameter/progress", 1.0, time)
+	var tweener := tween.tween_property(bg_holder, "material:shader_parameter/progress", 1.0, time).from(0.0)
 	tween.tween_callback(emit_signal.bind('transition_finished'))
 	return tweener

addons/dialogic/Modules/Background/subsystem_backgrounds.gd

@@ -94,6 +94,9 @@ func update_background(scene:String = '', argument:String = '', fade_time:float
 		trans_node.prev_scene = old_viewport.get_meta('node', null)
 		trans_node.prev_texture = old_viewport.get_child(0).get_texture()
 		old_viewport.get_meta('node')._custom_fade_out(fade_time)
+		old_viewport.hide()
+		# TODO We have to call this again here because of https://github.com/godotengine/godot/issues/23729
+		old_viewport.get_child(0).render_target_update_mode = SubViewport.UPDATE_ALWAYS
 		trans_node.transition_finished.connect(old_viewport.queue_free)
 	if new_viewport:
 		trans_node.next_scene = new_viewport.get_meta('node', null)
@@ -104,12 +107,25 @@ func update_background(scene:String = '', argument:String = '', fade_time:float
 		background_holder.remove_meta('current_viewport')
 
 	add_child(trans_node)
-	trans_node._fade()
-	trans_node.transition_finished.connect(trans_node.queue_free)
+	if fade_time == 0:
+		trans_node.transition_finished.emit()
+		_on_transition_finished(background_holder, trans_node)
+	else:
+		trans_node.transition_finished.connect(_on_transition_finished.bind(background_holder, trans_node))
+		trans_node._fade()
 
 	background_changed.emit(info)
 
 
+func _on_transition_finished(background_node:DialogicNode_BackgroundHolder, transition_node:DialogicBackgroundTransition) -> void:
+	if background_node.has_meta("current_viewport"):
+		if background_node.get_meta("current_viewport").get_meta("node", null) == transition_node.next_scene:
+			background_node.get_meta("current_viewport").show()
+	background_node.material = null
+	background_node.color = Color.TRANSPARENT
+	transition_node.queue_free()
+
+
 func add_background_node(scene:PackedScene, parent:DialogicNode_BackgroundHolder) -> SubViewportContainer:
 	var v_con := SubViewportContainer.new()
 	var viewport := SubViewport.new()
@@ -122,14 +138,15 @@ func add_background_node(scene:PackedScene, parent:DialogicNode_BackgroundHolder
 		return null
 
 	parent.add_child(v_con)
-	v_con.visible = false
+	v_con.hide()
 	v_con.stretch = true
 	v_con.size = parent.size
 	v_con.set_anchors_preset(Control.PRESET_FULL_RECT)
 
 	v_con.add_child(viewport)
 	viewport.transparent_bg = true
 	viewport.disable_3d = true
+	viewport.render_target_update_mode = SubViewport.UPDATE_ALWAYS
 
 	viewport.add_child(b_scene)
 	b_scene.viewport = viewport

addons/dialogic/Modules/DefaultLayoutParts/Layer_FullBackground/full_background_layer.tscn

@@ -1,14 +1,7 @@
-[gd_scene load_steps=5 format=3 uid="uid://c1k5m0w3r40xf"]
+[gd_scene load_steps=3 format=3 uid="uid://c1k5m0w3r40xf"]
 
 [ext_resource type="Script" path="res://addons/dialogic/Modules/DefaultLayoutParts/Layer_FullBackground/full_background_layer.gd" id="1_tu40u"]
 [ext_resource type="Script" path="res://addons/dialogic/Modules/Background/node_background_holder.gd" id="2_ghan2"]
-[ext_resource type="Shader" path="res://addons/dialogic/Modules/Background/Transitions/default_transition_shader.gdshader" id="2_mwc4m"]
-
-[sub_resource type="ShaderMaterial" id="ShaderMaterial_msuxf"]
-shader = ExtResource("2_mwc4m")
-shader_parameter/progress = 0.0
-shader_parameter/feather = 0.1
-shader_parameter/keep_aspect_ratio = false
 
 [node name="BackgroundLayer" type="Control"]
 layout_mode = 3
@@ -20,11 +13,11 @@ grow_vertical = 2
 script = ExtResource("1_tu40u")
 
 [node name="DialogicNode_BackgroundHolder" type="ColorRect" parent="."]
-material = SubResource("ShaderMaterial_msuxf")
 layout_mode = 1
 anchors_preset = 15
 anchor_right = 1.0
 anchor_bottom = 1.0
 grow_horizontal = 2
 grow_vertical = 2
+mouse_filter = 2
 script = ExtResource("2_ghan2")

addons/dialogic/Modules/DefaultLayoutParts/Layer_VN_Portraits/vn_portrait_layer.tscn

@@ -10,6 +10,7 @@ anchor_right = 1.0
 anchor_bottom = 1.0
 grow_horizontal = 2
 grow_vertical = 2
+mouse_filter = 2
 script = ExtResource("1_1i7em")
 
 [node name="Portraits" type="Control" parent="."]