#49: reduce cost of mach effects when not in atmosphere

Author: JonnyOThan

CHANGELOG.md

@@ -8,6 +8,7 @@
 - Avoid creating ShipEffects VesselModule for non-loaded vessels
 - Cache references to mixer groups
 - Fix NRE in comb filter during launch or when parts break
+- Reduce performance cost of mach effects when not in atmosphere
 
 ## 0.9.13 - 2026-04-20
 

Source/RocketSoundEnhancement/EffectBehaviours/RSE_AudioEffects.cs

@@ -241,8 +241,6 @@ public void FixedUpdate()
                     doppler = Mathf.MoveTowards(doppler, dopplerRaw, 0.5f * TimeWarp.fixedDeltaTime);
                 }
 
-                angle = (1 + Vector3.Dot(hostPart.vessel.GetComponent<ShipEffects>().MachTipCameraNormal, (transform.up + hostPart.vessel.velocityD).normalized)) * 90;
-
                 bool isActiveAndInternal = hostPart.vessel.isActiveVessel && (InternalCamera.Instance.isActive || MapView.MapCamera.isActiveAndEnabled);
                 if (isActiveAndInternal)
                 {
@@ -251,10 +249,14 @@ public void FixedUpdate()
                     return;
                 }
 
+                var shipEffects = hostPart.vessel.GetComponent<ShipEffects>();
+
+                angle = shipEffects.Angle;
+
                 if (Settings.MachEffectsAmount > 0)
                 {
-                    mach = Mathf.Clamp01(hostPart.vessel.GetComponent<ShipEffects>().Mach);
-                    machAngle = hostPart.vessel.GetComponent<ShipEffects>().MachAngle;
+                    mach = Mathf.Clamp01(shipEffects.Mach);
+                    machAngle = shipEffects.MachAngle;
                     machPass = Mathf.Lerp(1, Settings.MachEffectLowerLimit, Mathf.Clamp01(angle / machAngle) * mach);
                 }
                 else

Source/RocketSoundEnhancement/PartModules/RSE_Module.cs

@@ -184,8 +184,6 @@ public virtual void FixedUpdate()
                     doppler = Mathf.MoveTowards(doppler, dopplerRaw, 0.5f * TimeWarp.fixedDeltaTime);
                 }
 
-                angle = (1 + Vector3.Dot(vessel.GetComponent<ShipEffects>().MachTipCameraNormal, (transform.up + vessel.velocityD).normalized)) * 90;
-
                 bool isActiveAndInternal = vessel == FlightGlobals.ActiveVessel && InternalCamera.Instance.isActive;
                 if (isActiveAndInternal)
                 {
@@ -194,10 +192,14 @@ public virtual void FixedUpdate()
                     return;
                 }
 
+                var shipEffects = vessel.GetComponent<ShipEffects>();
+
+                angle = shipEffects.Angle;
+
                 if (Settings.MachEffectsAmount > 0)
                 {
-                    mach = Mathf.Clamp01(vessel.GetComponent<ShipEffects>().Mach);
-                    machAngle = vessel.GetComponent<ShipEffects>().MachAngle;
+                    mach = Mathf.Clamp01(shipEffects.Mach);
+                    machAngle = shipEffects.MachAngle;
                     machPass = Mathf.Lerp(1, Settings.MachEffectLowerLimit, Mathf.Clamp01(angle / machAngle) * mach);
                 }
                 else

Source/RocketSoundEnhancement/ShipEffects.cs

@@ -42,7 +42,6 @@ public static AerodynamicsFX AeroFX
         public float MachAngle = 90;
         public float MachPass = 1;
         public float Mach = 0;
-        public Vector3 MachTipCameraNormal = new Vector3();
 
         public bool SonicBoomed = true;
 
@@ -224,27 +223,24 @@ private void FixedUpdate()
             {
                 VesselMass -= excludedPart.mass;
             }
+        }
+
+        private void LateUpdate()
+        {
+            if (!HighLogic.LoadedSceneIsFlight || !initialized || gamePaused || noPhysics || ignoreVessel)
+                return;
+
+            if (vesselDataDirty)
+            {
+                CacheVesselData();
+            }
 
             if (Settings.EnableAudioEffects && Settings.MufflerQuality > AudioMufflerQuality.Normal)
             {
                 bool isActiveAndInternal = vessel == FlightGlobals.ActiveVessel && InternalCamera.Instance.isActive;
-                var velocityDirection = vessel.velocityD.normalized * vessel.vesselSize.magnitude;
-                var positionTip = transform.position + velocityDirection;
-                var positionRear = transform.position - velocityDirection;
-                var vesselTip = transform.position;
-                var vesselRear = transform.position;
-                RaycastHit tipHit;
-
-                if (Physics.BoxCast(positionTip, vessel.vesselSize, -vessel.velocityD.normalized, out tipHit))
-                {
-                    vesselTip = tipHit.point;
-                }
-
                 var cameraPosition = CameraManager.GetCurrentCamera().transform.position;
 
-                MachTipCameraNormal = (cameraPosition - vesselTip).normalized;
                 Distance = Vector3.Distance(cameraPosition, transform.position);  
-                Angle = (1 + Vector3.Dot(MachTipCameraNormal, vessel.velocityD.normalized)) * 90;
 
                 if (isActiveAndInternal)
                 {
@@ -253,6 +249,25 @@ private void FixedUpdate()
                     return;
                 }
 
+                if (vessel.staticPressurekPa > 0)
+                {
+                    var vesselTip = transform.position;
+                    var velocityDirection = vessel.velocityD.normalized * vessel.vesselSize.magnitude;
+                    var positionTip = transform.position + velocityDirection;
+                    Vector3 MachTipCameraNormal = (cameraPosition - vesselTip).normalized;
+                    RaycastHit tipHit;
+
+                    if (Physics.BoxCast(positionTip, vessel.vesselSize, -vessel.velocityD.normalized, out tipHit))
+                    {
+                        vesselTip = tipHit.point;
+                    }
+                    Angle = (1 + Vector3.Dot(MachTipCameraNormal, vessel.velocityD.normalized)) * 90;
+                }
+                else
+                {
+                    Angle = 0;
+                }
+
                 if (Settings.MachEffectsAmount > 0)
                 {
                     Mach = (float)vessel.mach * Mathf.Clamp01((float)(vessel.staticPressurekPa * 1000) / 404.1f);
@@ -266,17 +281,6 @@ private void FixedUpdate()
                     MachPass = 1;
                 }
             }
-        }
-
-        private void LateUpdate()
-        {
-            if (!HighLogic.LoadedSceneIsFlight || !initialized || gamePaused || noPhysics || ignoreVessel)
-                return;
-
-            if (vesselDataDirty)
-            {
-                CacheVesselData();
-            }
 
             foreach (var soundLayerGroup in ShipEffectsConfig.SoundLayerGroups)
             {