TwoHandScaleLogic.cs

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// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License. See LICENSE in the project root for license information.

using System.Collections.Generic;
using UnityEngine;

namespace HoloToolkit.Unity.InputModule.Utilities.Interactions
{
    public class TwoHandScaleLogic
    {
        private Vector3 m_startObjectScale;
        private float m_startHandDistanceMeters;

        public virtual void Setup(Dictionary<uint, Vector3> handsPressedMap, Transform manipulationRoot)
        {
            m_startHandDistanceMeters = GetMinDistanceBetweenHands(handsPressedMap);
            m_startObjectScale = manipulationRoot.transform.localScale;
        }

        public virtual Vector3 UpdateMap(Dictionary<uint, Vector3> handsPressedMap)
        {
            var ratioMultiplier = GetMinDistanceBetweenHands(handsPressedMap) / m_startHandDistanceMeters;
            return m_startObjectScale * ratioMultiplier;
        }

        private float GetMinDistanceBetweenHands(Dictionary<uint, Vector3> handsPressedMap)
        {
            var result = float.MaxValue;
            Vector3[] handLocations = new Vector3[handsPressedMap.Values.Count];
            handsPressedMap.Values.CopyTo(handLocations, 0);
            for (int i = 0; i < handLocations.Length; i++)
            {
                for (int j = i + 1; j < handLocations.Length; j++)
                {
                    var distance = Vector3.Distance(handLocations[i], handLocations[j]);
                    if (distance < result)
                    {
                        result = distance;
                    }
                }
            }
            return result;
        }
    }
}