297 lines
13 KiB
C#
297 lines
13 KiB
C#
using System;
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#region License
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//
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// This file is part of the ANX.Framework created by the "ANX.Framework developer group".
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//
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// This file is released under the Ms-PL license.
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//
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//
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//
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// Microsoft Public License (Ms-PL)
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//
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// This license governs use of the accompanying software. If you use the software, you accept this license.
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// If you do not accept the license, do not use the software.
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//
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// 1.Definitions
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// The terms "reproduce," "reproduction," "derivative works," and "distribution" have the same meaning
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// here as under U.S. copyright law.
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// A "contribution" is the original software, or any additions or changes to the software.
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// A "contributor" is any person that distributes its contribution under this license.
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// "Licensed patents" are a contributor's patent claims that read directly on its contribution.
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//
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// 2.Grant of Rights
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// (A) Copyright Grant- Subject to the terms of this license, including the license conditions and limitations
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// in section 3, each contributor grants you a non-exclusive, worldwide, royalty-free copyright license to
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// reproduce its contribution, prepare derivative works of its contribution, and distribute its contribution
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// or any derivative works that you create.
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// (B) Patent Grant- Subject to the terms of this license, including the license conditions and limitations in
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// section 3, each contributor grants you a non-exclusive, worldwide, royalty-free license under its licensed
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// patents to make, have made, use, sell, offer for sale, import, and/or otherwise dispose of its contribution
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// in the software or derivative works of the contribution in the software.
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//
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// 3.Conditions and Limitations
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// (A) No Trademark License- This license does not grant you rights to use any contributors' name, logo, or trademarks.
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// (B) If you bring a patent claim against any contributor over patents that you claim are infringed by the software, your
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// patent license from such contributor to the software ends automatically.
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// (C) If you distribute any portion of the software, you must retain all copyright, patent, trademark, and attribution
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// notices that are present in the software.
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// (D) If you distribute any portion of the software in source code form, you may do so only under this license by including
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// a complete copy of this license with your distribution. If you distribute any portion of the software in compiled or
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// object code form, you may only do so under a license that complies with this license.
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// (E) The software is licensed "as-is." You bear the risk of using it. The contributors give no express warranties, guarantees,
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// or conditions. You may have additional consumer rights under your local laws which this license cannot change. To the
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// extent permitted under your local laws, the contributors exclude the implied warranties of merchantability, fitness for a
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// particular purpose and non-infringement.
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#endregion // License
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namespace ANX.Framework
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{
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public class Curve
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{
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private CurveKeyCollection keys;
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private CurveLoopType preLoop;
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private CurveLoopType postLoop;
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public CurveLoopType PreLoop
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{
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get { return preLoop; }
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set { preLoop = value; }
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}
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public CurveLoopType PostLoop
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{
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get { return postLoop; }
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set { postLoop = value; }
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}
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public CurveKeyCollection Keys
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{
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get
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{
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return keys;
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}
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}
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public Boolean IsConstant
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{
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get
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{
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return this.keys.Count <= 1;
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}
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}
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public Curve Clone()
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{
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Curve result = new Curve();
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result.keys = this.keys.Clone();
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result.preLoop = this.preLoop;
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result.postLoop = this.postLoop;
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return result;
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}
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public Curve()
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{
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this.keys = new CurveKeyCollection();
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}
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#region tangent calculation
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//formulas from: http://msdn.microsoft.com/de-de/library/microsoft.xna.framework.curvetangent%28v=xnagamestudio.40%29.aspx
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public void ComputeTangent(Int32 index, CurveTangent tangentInOutType)
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{
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if (index < 0 || index > keys.Count)
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{
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throw new ArgumentOutOfRangeException();
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}
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CurveKey prev = index > 0 ? this.keys[index - 1] : this.keys[index];
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CurveKey current = this.keys[index];
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current.TangentIn = 0;
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CurveKey next = index < this.keys.Count - 1 ? this.keys[index + 1] : this.keys[index];
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switch (tangentInOutType)
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{
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case CurveTangent.Flat:
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current.TangentIn = 0;
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current.TangentOut = 0;
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break;
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case CurveTangent.Linear:
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current.TangentIn = current.Value - prev.Value;
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current.TangentOut = next.Value - current.Value;
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break;
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case CurveTangent.Smooth:
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current.TangentIn = ((next.Value - prev.Value) * ((current.Position - prev.Position) / (next.Position - prev.Position)));
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current.TangentOut = ((next.Value - prev.Value) * ((next.Position - current.Position) / (next.Position - prev.Position)));
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break;
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}
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}
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public void ComputeTangent(Int32 index, CurveTangent tangentInType, CurveTangent tangentOutType)
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{
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if (index < 0 || index > keys.Count)
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{
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throw new ArgumentOutOfRangeException();
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}
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CurveKey prev = index > 0 ? this.keys[index - 1] : this.keys[index];
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CurveKey current=this.keys[index];
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current.TangentIn = 0;
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CurveKey next=index <this.keys.Count-1? this.keys[index + 1] : this.keys[index];
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switch (tangentInType)
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{
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case CurveTangent.Flat:
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current.TangentIn = 0;
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break;
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case CurveTangent.Linear:
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current.TangentIn = current.Value - prev.Value;
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break;
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case CurveTangent.Smooth:
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current.TangentIn=((next.Value-prev.Value)*((current.Position-prev.Position)/(next.Position-prev.Position)));
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break;
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}
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switch (tangentOutType)
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{
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case CurveTangent.Flat:
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current.TangentOut = 0;
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break;
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case CurveTangent.Linear:
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current.TangentOut = next.Value - current.Value;
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break;
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case CurveTangent.Smooth:
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current.TangentOut=((next.Value-prev.Value)*((next.Position-current.Position)/(next.Position-prev.Position)));
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break;
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}
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}
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public void ComputeTangents(CurveTangent tangentInOutType)
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{
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for (int i = 0; i < this.keys.Count; ++i)
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{
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this.ComputeTangent(i, tangentInOutType);
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}
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}
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public void ComputeTangents(CurveTangent tangentInType, CurveTangent tangentOutType)
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{
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for (int i = 0; i < this.keys.Count; ++i)
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{
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this.ComputeTangent(i, tangentInType,tangentOutType);
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}
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}
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#endregion
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public Single Evaluate(Single position)
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{
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//Get first and last Point
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CurveKey first = keys[0];
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CurveKey last = keys[keys.Count - 1];
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float timeSpan=this.keys[this.keys.Count-1].Position-this.keys[0].Position;
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//wanted point before first point
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if (position < first.Position)
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{
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// Description from : http://msdn.microsoft.com/en-us/library/microsoft.xna.framework.curvelooptype.aspx
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switch (this.PreLoop)
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{
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case CurveLoopType.Constant:
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//The Curve will evaluate to its first key for positions before the first point in the Curve and to the last key for positions after the last point.
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return first.Value;
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case CurveLoopType.Linear:
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// Linear interpolation will be performed to determine the value.
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return first.Value - first.TangentIn * (first.Position - position);
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case CurveLoopType.Cycle:
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// Positions specified past the ends of the curve will wrap around to the opposite side of the Curve.
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return this.interpolate(position%timeSpan);
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case CurveLoopType.CycleOffset:
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//Positions specified past the ends of the curve will wrap around to the opposite side of the Curve.
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//The value will be offset by the difference between the values of the first and last CurveKey
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//multiplied by the number of times the position wraps around. If the position is before the first
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//point in the Curve, the difference will be subtracted from its value; otherwise, the difference
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//will be added.
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float difference = (this.keys[this.keys.Count - 1].Value - this.keys[0].Value) * (position / timeSpan);
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return this.interpolate(position % timeSpan)-difference;
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case CurveLoopType.Oscillate:
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//Positions specified past the ends of the Curve act as an offset from the same side of the Curve
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//toward the opposite side.
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return this.interpolate(timeSpan-(position % timeSpan));
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}
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}
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//wanted point behind last point
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else if (position > last.Position)
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{
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int cycle;
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switch (this.PostLoop)
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{
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case CurveLoopType.Constant:
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//The Curve will evaluate to its first key for positions before the first point in the Curve and to
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//the last key for positions after the last point.
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return last.Value;
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case CurveLoopType.Linear:
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//Linear interpolation will be performed to determine the value.
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return last.Value + last.TangentOut * (position - last.Position);
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case CurveLoopType.Cycle:
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// Positions specified past the ends of the curve will wrap around to the opposite side of the Curve.
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return this.interpolate(position%timeSpan);
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case CurveLoopType.CycleOffset:
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//Positions specified past the ends of the curve will wrap around to the opposite side of the Curve.
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//The value will be offset by the difference between the values of the first and last CurveKey
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//multiplied by the number of times the position wraps around. If the position is before the first
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//point in the Curve, the difference will be subtracted from its value; otherwise, the difference
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//will be added.
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float difference = (this.keys[this.keys.Count - 1].Value - this.keys[0].Value) * (position / timeSpan);
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return this.interpolate(position % timeSpan)+difference;
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case CurveLoopType.Oscillate:
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//Positions specified past the ends of the Curve act as an offset from the same side of the Curve
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//toward the opposite side.
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return this.interpolate(timeSpan - (position % timeSpan));
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}
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}
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//in curve
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return interpolate(position);
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}
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private float interpolate(float position)
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{
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//interpolate inside the curve with cubic hermite:
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http://forums.create.msdn.com/forums/p/53392/323814.aspx
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//assume position is inside curve
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CurveKey a = this.keys[0];
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CurveKey b;
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for (int i = 1; i < this.keys.Count; i++)
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{
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b = this.Keys[i];
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if (b.Position >= position)
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{
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//stepping
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if (a.Continuity == CurveContinuity.Step)
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{
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return a.Value;
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}
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//smooth
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//get the location between a and b in [0,1]
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float moment = (position - a.Position) / (b.Position - a.Position);
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return MathHelper.Hermite(a.Value, a.TangentOut, b.Value, b.TangentOut, moment);
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}
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//get next pair
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a = b;
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}
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return 0f;
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}
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}
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}
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