Mockup for linearly normalized eye gaze values

VRCFaceTracking.Core/Params/Expressions/UnifiedExpressionsParameters.cs

@@ -28,6 +28,10 @@ private static (string paramName, Parameter paramLiteral)[] IsEyeParameter(IPara
         new EParam("v2/Eye", exp => exp.Eye.Combined().Gaze),
         new EParam("v2/EyeLeft", exp => exp.Eye.Left.Gaze),
         new EParam("v2/EyeRight", exp => exp.Eye.Right.Gaze),
+
+        new EParam("v2/EyeLinear", exp => exp.Eye.Combined().Gaze.ToNormalized()),
+        new EParam("v2/EyeLeftLinear", exp => exp.Eye.Left.Gaze.ToNormalized()),
+        new EParam("v2/EyeRightLinear", exp => exp.Eye.Right.Gaze.ToNormalized()),
 
         // Use when tracking interface is sending verbose gaze data.
         new NativeParameter<Vector2>(exp =>
@@ -311,4 +315,4 @@ private static IEnumerable<EParam> GetAllBaseSimpleExpressions() =>
            new EParam("v2/" + simple.ToString(), exp => GetSimpleShape(exp, simple), 0.0f));
 
     private static float GetSimpleShape(UnifiedTrackingData data, UnifiedSimpleExpressions expression) => UnifiedSimplifier.ExpressionMap[expression].Invoke(data);
-}
+}

VRCFaceTracking.Core/Types/Vector2.cs

@@ -48,5 +48,26 @@ public float ToYaw()
 
         public float ToPitch()
         => -(float)(Math.Atan(y) * (180 / Math.PI));
+
+        /// <summary>
+        /// Converts the Tobii normalized eye value to a normalized yaw value from -1 to 1, representing -45 to 45 degrees.
+        /// </summary>
+        public float ToNormalizedYaw()
+        => Remap(ToYaw(), -45, 45, -1, 1);
+
+        /// <summary>
+        /// Converts the Tobii normalized eye value to a normalized pitch value from -1 to 1, representing -45 to 45 degrees.
+        /// </summary>
+        public float ToNormalizedPitch()
+        => Remap(ToPitch(), -45, 45, -1, 1);
+
+        //return a remade vector2 that represents the remapped values
+        public Vector2 ToNormalized()
+        => new Vector2(ToNormalizedYaw(), ToNormalizedPitch());
+
+        private float Remap(float source, float sourceFrom, float sourceTo, float targetFrom, float targetTo)
+        {
+            return targetFrom + (source-sourceFrom)*(targetTo-targetFrom)/(sourceTo-sourceFrom);
+        }
     }
-}
+}