From f873e81bf03b7ea5b0f5b1120953ce09ff02a661 Mon Sep 17 00:00:00 2001
From: Sven Eberhardt <sven2@goldwipf.de>
Date: Sun, 9 Aug 2015 19:28:07 -0400
Subject: [PATCH] Fade airplane sound pitch when motor is turned on and off.

---
 .../Vehicles.ocd/Airplane.ocd/Script.c        | 64 +++++++++++++++----
 1 file changed, 50 insertions(+), 14 deletions(-)

diff --git a/planet/Objects.ocd/Vehicles.ocd/Airplane.ocd/Script.c b/planet/Objects.ocd/Vehicles.ocd/Airplane.ocd/Script.c
index e2b17e129..3b28a860a 100644
--- a/planet/Objects.ocd/Vehicles.ocd/Airplane.ocd/Script.c
+++ b/planet/Objects.ocd/Vehicles.ocd/Airplane.ocd/Script.c
@@ -143,7 +143,7 @@ public func ContainedStop(object clonk)
 
 public func StartFlight(int new_throttle)
 {
-	AddEffect("IntSoundDelay",this,1,1,this);
+	SetPropellerSpeedTarget(100);
 	SetAction("Fly");
 	throttle = new_throttle;
 }
@@ -151,8 +151,7 @@ public func StartFlight(int new_throttle)
 public func StartInstantFlight(int angle, int new_throttle)
 {
 	angle -= 10;
-	var effect = AddEffect("IntSoundDelay",this,1,1,this);
-	effect.Immediate = true;
+	SetPropellerSpeed(100);
 	SetAction("Fly");
 	throttle = new_throttle;
 	thrust = new_throttle;
@@ -164,22 +163,12 @@ public func StartInstantFlight(int angle, int new_throttle)
 
 public func CancelFlight()
 {
-	RemoveEffect("IntSoundDelay",this);
-	Sound("PropellerLoop",0,100,nil,-1);
+	SetPropellerSpeedTarget(0);
 	SetAction("Land");
 	rdir = 0;
 	throttle = 0;
 }
 
-private func FxIntSoundDelayTimer(object target, effect, int timer)
-{
-	if(timer >= 78 || (effect.Immediate && timer >= 5))
-	{
-		Sound("PropellerLoop",0,100,nil,1);
-		return -1;
-	}
-}
-
 private func FxIntPlaneTimer(object target, effect, int timer)
 {
 	//Lift
@@ -367,6 +356,53 @@ public func PlaneDismount(object clonk)
 	return true;
 }
 
+
+/* Propeller sound */
+
+local prop_speed, prop_speed_target, prop_speed_timer; // current and target propeller speed [0, 100]
+
+// Instantly set new propeller speed
+private func SetPropellerSpeed(int new_speed)
+{
+	if (prop_speed_timer)
+	{
+		RemoveTimer(this.PropellerSpeedTimer);
+		prop_speed_timer = false;
+	}
+	return SetPropellerSound(prop_speed = prop_speed_target = new_speed);
+}
+
+// Schedule fading to new propeller speed
+private func SetPropellerSpeedTarget(int new_speed_target)
+{
+	prop_speed_target = new_speed_target;
+	if (!prop_speed_timer) prop_speed_timer = AddTimer(this.PropellerSpeedTimer, 10);
+	return true;
+}
+
+// Execute fading to new propeller speed
+private func PropellerSpeedTimer()
+{
+	prop_speed = BoundBy(prop_speed_target, prop_speed - 10, prop_speed + 4);
+	if (prop_speed == prop_speed_target)
+	{
+		RemoveTimer(this.PropellerSpeedTimer);
+		prop_speed_timer = false;
+	}
+	return SetPropellerSound(prop_speed);
+}
+
+// Set propeller speed sound. 0 = off, 100 = max speed.
+private func SetPropellerSound(int speed)
+{
+	if (speed <= 0)
+		return Sound("PropellerLoop",0,100,nil,-1);
+	else
+		return Sound("PropellerLoop",0,100,nil,1,0,(speed-100)*2/3);
+}
+
+/* Properties */
+
 func IsShipyardProduct() { return true; }
 
 local ActMap = {