add engine sound

scenes/car.tscn

@@ -1,10 +1,11 @@
-[gd_scene load_steps=10 format=3 uid="uid://0g7qqh7naniv"]
+[gd_scene load_steps=11 format=3 uid="uid://0g7qqh7naniv"]
 
 [ext_resource type="Script" path="res://scripts/car_node.gd" id="1_0tin3"]
 [ext_resource type="Script" path="res://scripts/car.gd" id="1_i5tet"]
 [ext_resource type="Texture2D" uid="uid://mqdujngircok" path="res://sprites/car_features.png" id="3_ts6mm"]
 [ext_resource type="Texture2D" uid="uid://e5aeyl47wi8p" path="res://sprites/car_body.png" id="4_lps13"]
 [ext_resource type="Script" path="res://scripts/label_round.gd" id="5_vheit"]
+[ext_resource type="PackedScene" uid="uid://dl7r8s5sxyvlw" path="res://scenes/enginesound.tscn" id="6_v21se"]
 
 [sub_resource type="CapsuleShape2D" id="CapsuleShape2D_bj1hp"]
 radius = 8.0
@@ -106,5 +107,7 @@ libraries = {
 "": SubResource("AnimationLibrary_55lyd")
 }
 
+[node name="Enginesound" parent="CharacterBody_Car" instance=ExtResource("6_v21se")]
+
 [connection signal="timeout" from="CharacterBody_Car/resetTimer" to="CharacterBody_Car" method="_on_reset_timer_timeout"]
 [connection signal="timeout" from="CharacterBody_Car/collisionEnableTimer" to="CharacterBody_Car" method="_on_collision_enable_timer_timeout"]

scenes/enginesound.tscn

@@ -0,0 +1,13 @@
+[gd_scene load_steps=3 format=3 uid="uid://dl7r8s5sxyvlw"]
+
+[ext_resource type="Script" path="res://scripts/enginesound.gd" id="1_1xhsl"]
+
+[sub_resource type="AudioStreamGenerator" id="AudioStreamGenerator_kj4va"]
+buffer_length = 0.05
+
+[node name="Enginesound" type="Node"]
+script = ExtResource("1_1xhsl")
+
+[node name="Player" type="AudioStreamPlayer" parent="."]
+stream = SubResource("AudioStreamGenerator_kj4va")
+bus = &"Motor"

scripts/car.gd

@@ -22,6 +22,7 @@ const STANDSTILLSPEED=0.5
 var wheel_base = 60*0.5
 
 var engine_power = 350
+var applied_engine_power=0
 
 var friction = -0.5
 var drag = -0.0005
@@ -70,6 +71,8 @@ var autosteer_enabled=false
 @onready var collision_shape: CollisionShape2D = $CollisionShape2D
 @onready var collision_enable_timer: Timer = $collisionEnableTimer
 
+@onready var enginesound: Node = $Enginesound
+
 var playerid=0
 var finalTime=-1
 
@@ -81,7 +84,7 @@ func _ready() -> void:
 func _physics_process(delta: float) -> void:
 	acceleration=Vector2.ZERO
 	check_markers()
-	get_input()
+	get_input(delta)
 	apply_friction()
 	calculate_steering(delta)
 	velocity +=acceleration*delta
@@ -108,6 +111,10 @@ func _physics_process(delta: float) -> void:
 	if velocity.length() > resetcar_movingspeed:
 		reset_timer.stop()
 		
+		
+	enginesound.setCarSpeed(velocity.length())
+	enginesound.setCarAcceleration(applied_engine_power/engine_power,delta)
+	#print("Car Accel="+str(acceleration.length()) +"/"+str(engine_power))
 
 
 func _on_reset_timer_timeout() -> void:
@@ -121,7 +128,7 @@ func apply_friction():
 	
 	acceleration+=drag_force+friction_force
 	
-func get_input():
+func get_input(delta:float):
 	
 	
 	const distance_inf=1000
@@ -157,11 +164,12 @@ func get_input():
 			steer_direction=0 #drive straight
 		
 		
-	
+	applied_engine_power=0
 	if running:
 		if Input.is_action_pressed(Gamestate.userinput_prefix+str(playerid)):
 			#velocity = transform.x * 500
-			acceleration = transform.x * engine_power
+			applied_engine_power=engine_power
+			
 			
 			if not autosteer_enabled: #start autosteer when accelerate is pressed
 				autosteer_enabled=true 
@@ -172,7 +180,8 @@ func get_input():
 				autoreset=false
 		#if Input.is_action_pressed("ui_down"):
 			#acceleration = transform.x * braking
-		
+	
+	acceleration = transform.x * applied_engine_power
 		
 	if autoreset and running:
 		acceleration = transform.x * braking #drive backwards

scripts/enginesound.gd

@@ -0,0 +1,74 @@
+extends Node
+
+
+var sample_hz = 44100.0 # Keep the number of samples to mix low, GDScript is not super fast.
+@onready var noise = FastNoiseLite.new()
+
+var phase_rotation = 0.0
+
+var vol_master=20.0
+var vol_overtones=0.0
+var vol_overtones_sample=0
+var vol_basefrequency=0.0
+var vol_basefrequency_sample=0 
+
+var playback: AudioStreamPlayback = null # Actual playback stream, assigned in _ready().
+
+var carspeed=0 #m/s
+var caraccel:float=0 #0 to 1
+var increment_motorrotation=1.0/2
+var offset_rotation=0
+
+
+
+func setCarSpeed(s):
+	carspeed=s
+func setCarAcceleration(a,delta):
+	a=min(1.0,max(a,0.0))
+	var maxchange=2.0*delta
+	caraccel+=min(maxchange,max(a-caraccel,-maxchange))
+	
+
+func _fill_buffer():
+	var increment_motorrotation = carspeed*increment_motorrotation / sample_hz
+
+
+	var to_fill = playback.get_frames_available()
+	while to_fill > 0:
+		var sample=0
+		
+		var maxsamplevolumechange=100/sample_hz
+		vol_basefrequency_sample+=clamp(vol_basefrequency-vol_basefrequency_sample,-maxsamplevolumechange,maxsamplevolumechange)
+		vol_overtones_sample+=clamp(vol_overtones-vol_overtones_sample,-maxsamplevolumechange,maxsamplevolumechange)
+		
+		sample+=noise.get_noise_2d(cos(phase_rotation*TAU)*2,sin(phase_rotation*TAU)*2)*vol_basefrequency_sample
+		sample+=noise.get_noise_2d(cos(phase_rotation*6*TAU)*0.5,sin(phase_rotation*3*TAU)*0.5)*vol_overtones_sample/2
+		sample+=noise.get_noise_2d(cos(phase_rotation*3*TAU)*1,sin(phase_rotation*2*TAU)*1)*vol_overtones_sample
+		
+		
+		
+		playback.push_frame(Vector2.ONE * sample*vol_master) # Audio frames are stereo.
+		
+		
+		phase_rotation = fmod(phase_rotation + increment_motorrotation, 1.0)
+		
+		to_fill -= 1
+
+
+func _process(_delta):
+	
+	
+	vol_basefrequency=caraccel*clamp(remap(carspeed,20.0,100.0,0.0,1.0),0,1)*clamp(remap(carspeed,200.0,500.0,1.0,0.5),0,1)
+	vol_overtones=clamp(remap(carspeed,20.0,100.0,0.0,1.0),0,1)*clamp(remap(carspeed,200.0,500.0,1.0,0.5),0,1)
+	
+	_fill_buffer()
+
+
+func _ready():
+	# Setting mix rate is only possible before play().
+	$Player.stream.mix_rate = sample_hz
+	$Player.play()
+	playback = $Player.get_stream_playback()
+	# `_fill_buffer` must be called *after* setting `playback`,
+	# as `fill_buffer` uses the `playback` member variable.
+	_fill_buffer()