Reduce mesh rotation allocs

src/Math/babylon.math.ts

@@ -2011,7 +2011,10 @@
         }
 
         public static RotationAxis(axis: Vector3, angle: number): Quaternion {
-            var result = new Quaternion();
+            return Quaternion.RotationAxisToRef(axis, angle, new Quaternion());
+        }
+
+        public static RotationAxisToRef(axis: Vector3, angle: number, result: Quaternion): Quaternion {
             var sin = Math.sin(angle / 2);
 
             axis.normalize();
@@ -2033,14 +2036,10 @@
         }
 
         public static RotationYawPitchRoll(yaw: number, pitch: number, roll: number): Quaternion {
-            var result = new Quaternion();
-
-            Quaternion.RotationYawPitchRollToRef(yaw, pitch, roll, result);
-
-            return result;
+            return Quaternion.RotationYawPitchRollToRef(yaw, pitch, roll, new Quaternion());
         }
 
-        public static RotationYawPitchRollToRef(yaw: number, pitch: number, roll: number, result: Quaternion): void {
+        public static RotationYawPitchRollToRef(yaw: number, pitch: number, roll: number, result: Quaternion): Quaternion {
             // Produces a quaternion from Euler angles in the z-y-x orientation (Tait-Bryan angles)
             var halfRoll = roll * 0.5;
             var halfPitch = pitch * 0.5;
@@ -2057,6 +2056,8 @@
             result.y = (sinYaw * cosPitch * cosRoll) - (cosYaw * sinPitch * sinRoll);
             result.z = (cosYaw * cosPitch * sinRoll) - (sinYaw * sinPitch * cosRoll);
             result.w = (cosYaw * cosPitch * cosRoll) + (sinYaw * sinPitch * sinRoll);
+
+            return result;
         }
 
         public static RotationAlphaBetaGamma(alpha: number, beta: number, gamma: number): Quaternion {

src/Mesh/babylon.abstractMesh.ts

@@ -361,6 +361,7 @@
             return this._isWorldMatrixFrozen;
         }
 
+        private static _rotationAxisCache = new Quaternion();
         public rotate(axis: Vector3, amount: number, space?: Space): void {
             axis.normalize();
 
@@ -370,8 +371,8 @@
             }
             var rotationQuaternion: Quaternion;
             if (!space || space === Space.LOCAL) {
-                rotationQuaternion = Quaternion.RotationAxis(axis, amount);
-                this.rotationQuaternion = this.rotationQuaternion.multiply(rotationQuaternion);
+                rotationQuaternion = Quaternion.RotationAxisToRef(axis, amount, AbstractMesh._rotationAxisCache);
+                this.rotationQuaternion.multiplyToRef(rotationQuaternion, this.rotationQuaternion);
             }
             else {
                 if (this.parent) {
@@ -380,8 +381,8 @@
 
                     axis = Vector3.TransformNormal(axis, invertParentWorldMatrix);
                 }
-                rotationQuaternion = Quaternion.RotationAxis(axis, amount);
-                this.rotationQuaternion = rotationQuaternion.multiply(this.rotationQuaternion);
+                rotationQuaternion = Quaternion.RotationAxisToRef(axis, amount, AbstractMesh._rotationAxisCache);
+                rotationQuaternion.multiplyToRef(this.rotationQuaternion, this.rotationQuaternion);
             }
         }
 
@@ -744,6 +745,7 @@
             this.position = Vector3.TransformCoordinates(vector3, this._localWorld);
         }
 
+        private static _lookAtVectorCache = new Vector3(0,0,0);
         public lookAt(targetPoint: Vector3, yawCor: number, pitchCor: number, rollCor: number): void {
             /// <summary>Orients a mesh towards a target point. Mesh must be drawn facing user.</summary>
             /// <param name="targetPoint" type="Vector3">The position (must be in same space as current mesh) to look at</param>
@@ -756,11 +758,12 @@
             pitchCor = pitchCor || 0;
             rollCor = rollCor || 0;
 
-            var dv = targetPoint.subtract(this.position);
+            var dv = AbstractMesh._lookAtVectorCache;
+            targetPoint.subtractToRef(this.position, dv);
             var yaw = -Math.atan2(dv.z, dv.x) - Math.PI / 2;
             var len = Math.sqrt(dv.x * dv.x + dv.z * dv.z);
             var pitch = Math.atan2(dv.y, len);
-            this.rotationQuaternion = Quaternion.RotationYawPitchRoll(yaw + yawCor, pitch + pitchCor, rollCor);
+            Quaternion.RotationYawPitchRollToRef(yaw + yawCor, pitch + pitchCor, rollCor, this.rotationQuaternion);
         }
 
         public attachToBone(bone: Bone, affectedMesh: AbstractMesh): void {