Improve tire marks

scenes/vehicle/tire_mark_decal.gd

@@ -0,0 +1,12 @@
+extends Decal
+
+var active := false:
+	set(value):
+		active = value
+		visible = value
+		if value:
+			$TireMarkTimer.start()
+
+
+func _on_tire_mark_timer_timeout() -> void:
+	active = false

scenes/vehicle/tire_mark_decal.tscn

@@ -0,0 +1,29 @@
+[gd_scene load_steps=5 format=3 uid="uid://0nh338l8d7ai"]
+
+[ext_resource type="Script" path="res://scenes/vehicle/tire_mark_decal.gd" id="1_pr6ks"]
+
+[sub_resource type="Gradient" id="Gradient_3xgt7"]
+colors = PackedColorArray(0, 0, 0, 1, 0.180005, 0.180005, 0.180005, 1)
+
+[sub_resource type="FastNoiseLite" id="FastNoiseLite_usc7i"]
+
+[sub_resource type="NoiseTexture2D" id="NoiseTexture2D_wvypd"]
+color_ramp = SubResource("Gradient_3xgt7")
+noise = SubResource("FastNoiseLite_usc7i")
+
+[node name="TireMarkDecal" type="Decal"]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0.8, -0.134349, 1.5)
+layers = 4
+size = Vector3(0.2, 1, 0.2)
+texture_albedo = SubResource("NoiseTexture2D_wvypd")
+upper_fade = 1e-05
+lower_fade = 1e-05
+distance_fade_enabled = true
+cull_mask = 1048572
+script = ExtResource("1_pr6ks")
+
+[node name="TireMarkTimer" type="Timer" parent="."]
+wait_time = 3.0
+one_shot = true
+
+[connection signal="timeout" from="TireMarkTimer" to="." method="_on_tire_mark_timer_timeout"]

scenes/vehicle/wheel_suspension.gd

@@ -33,7 +33,7 @@ var rolling_resistance_coefficient := 0.02
 var y_force := 0.0
 
 var wheel_inertia := 0.0
-var spin := 0.0 :
+var spin := 0.0:
 	set = set_spin, get = get_spin
 
 var z_vel := 0.0
@@ -50,6 +50,9 @@ var prev_spin := 0.0
 var prev_compress := 0.0
 var spring_curr_length := spring_length
 
+var tire_mark_pool := []
+var max_tire_mark_count := 500
+var prev_mark_pos := Vector3.ZERO
 
 @onready var car = get_parent() as BaseCar
 @onready var wheelmesh = $MeshInstance3D
@@ -64,18 +67,19 @@ func _ready() -> void:
 	set_target_position(Vector3.DOWN * (spring_length + tire_radius))
 
 	# Some sensible peak slip values just in case tire model fails to have them
-	peak_slip.x = 0.12 
-	peak_slip.y = 0.09 
+	peak_slip.x = 0.12
+	peak_slip.y = 0.09
+
+	tire_mark_pool.resize(max_tire_mark_count)
+
+	for i in range(max_tire_mark_count):
+		tire_mark_pool[i] = load("res://scenes/vehicle/tire_mark_decal.tscn").instantiate()
+		tire_mark_pool[i].active = false
+		get_tree().root.add_child(tire_mark_pool[i])
 
 
 func _process(delta: float) -> void:
-	$TireMarks.emitting = false
-	if abs(slip_vec.x) >= peak_slip.x or abs(slip_vec.y) >= peak_slip.y:
-		if local_vel.length() > 2.0:
-			$TireMarks.emitting = self.is_colliding()
-
 	_update_tire_squeal()
-
 	wheelmesh.position.y = -spring_curr_length
 	wheelmesh.rotate_x(wrapf(-spin * delta, 0, TAU))
 
@@ -93,6 +97,7 @@ func _physics_process(delta: float) -> void:
 	if is_finite(friction_power):
 		tire_wear = tire_model.update_tire_wear(tire_wear, friction_power, delta)
 		tire_temp = tire_model.update_tire_temps(tire_temp, friction_power, z_vel, delta)
+	_update_tire_marks()
 
 
 func set_params(params: WheelSuspensionParameters):
@@ -136,10 +141,30 @@ func _update_tire_squeal():
 	var y := absf(slip_vec.y)
 	var avg := (x + y) * 0.5
 	var pitch := clampf(avg, 0.65, 1.00)
-
 	$TireSqueal.pitch_scale = pitch
 
 
+func _update_tire_marks():
+	if local_vel.length() < 2.0:
+		return
+	if not is_colliding():
+		return
+
+	if abs(slip_vec.x) >= peak_slip.x or abs(slip_vec.y) >= peak_slip.y:
+		for mark in tire_mark_pool:
+			if mark.active:
+				continue
+
+			if global_position.distance_to(prev_mark_pos) < 0.15:
+				break
+
+			mark.global_position = global_position
+			mark.global_rotation = global_rotation.rotated(global_transform.basis.y, prev_mark_pos.angle_to(global_position))
+			prev_mark_pos = mark.global_position
+			mark.active = true
+			break
+
+
 func apply_forces(opposite_comp, delta):
 	############# Local forward velocity #############
 	local_vel = (global_transform.origin - prev_pos) / delta * global_transform.basis

scenes/vehicle/wheel_suspension.tscn

@@ -1,4 +1,4 @@
-[gd_scene load_steps=8 format=3 uid="uid://nelgdfamj8jh"]
+[gd_scene load_steps=5 format=3 uid="uid://nelgdfamj8jh"]
 
 [ext_resource type="Material" path="res://resources/materials/tire.tres" id="1"]
 [ext_resource type="Script" path="res://scenes/vehicle/wheel_suspension.gd" id="2"]
@@ -11,34 +11,16 @@ bottom_radius = 0.3
 height = 0.2
 radial_segments = 16
 
-[sub_resource type="ParticleProcessMaterial" id="ParticleProcessMaterial_3a5fp"]
-gravity = Vector3(0, 0, 0)
-
-[sub_resource type="StandardMaterial3D" id="StandardMaterial3D_ry7we"]
-albedo_color = Color(0.176471, 0.176471, 0.176471, 1)
-
-[sub_resource type="PlaneMesh" id="PlaneMesh_8qb03"]
-material = SubResource("StandardMaterial3D_ry7we")
-size = Vector2(0.2, 0.2)
-
 [node name="Wheel_br" type="RayCast3D"]
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0.8, 0, 1.5)
 script = ExtResource("2")
 
 [node name="MeshInstance3D" type="MeshInstance3D" parent="."]
 transform = Transform3D(-4.37114e-08, -1, 0, 1, -4.37114e-08, 0, 0, 0, 1, 0, 0, 0)
+layers = 2
 mesh = SubResource("10")
 skeleton = NodePath("")
 
-[node name="TireMarks" type="GPUParticles3D" parent="."]
-transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, -0.3, 0)
-emitting = false
-amount = 10000
-lifetime = 10.0
-visibility_aabb = AABB(-0.503298, -0.233458, -0.487277, 1.0066, 0.466916, 0.974553)
-process_material = SubResource("ParticleProcessMaterial_3a5fp")
-draw_pass_1 = SubResource("PlaneMesh_8qb03")
-
 [node name="TireSqueal" type="AudioStreamPlayer3D" parent="."]
 stream = ExtResource("3_2n5q2")
 bus = &"Car_Bus"