SilverLight

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C#

EaseOutRotationController.cs：源码内容

							﻿// Silver.Globe, version 0.11 for Silverlight 1.1 Alpha
// Copyright © Florian Krüsch (xaml-kru.com)
// xaml-kru.com/silverglobe
// This source is subject to the Microsoft Public License (Ms-PL).
// See http://www.microsoft.com/resources/sharedsource/licensingbasics/publiclicense.mspx.
// All other rights reserved.
using System;
using SilverGlobe.Math3D;
namespace SilverGlobe
{
    /// <summary>
    /// EaseOutRotationController controls the globe by easeing out a given rotation.
    /// </summary>
    internal sealed class EaseOutRotationController
    {
        #region Members
        private DateTime _lastTick;
        private Globe _globe;
        private Vector3D _axis;
        private Double _speed;
        #endregion
        #region Constructor
        public EaseOutRotationController(Globe globe)
        {
            _globe = globe;
        }
        #endregion
        #region Methods
        /// <summary>
        /// Start controlling the globe.
        /// </summary>
        public void Init(Vector3D axis, Double initialSpeed)
        {
            _lastTick = DateTime.Now;
            _speed = initialSpeed;
            _axis = axis;
        }
        #endregion
        #region Implementation
        public void Update()
        {            
            DateTime now = DateTime.Now;
            Double dt = (now - _lastTick).TotalSeconds;
            _lastTick = now;
            Double k = 0.2 / dt;
            if (k > 1) k = 1;
            // slow down
            Double ds = _speed * 0.97 - _speed;
            _speed += ds * k;
            _globe.Orientation *= Quaternion.ForRotation(_axis, _speed);
            _globe.Orientation.Normalize();
        }
        #endregion
    }
}

						