Spline.h

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/*
 * Copyright (C) 2005-2011 MaNGOS <http://getmangos.com/>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#ifndef TRINITYSERVER_SPLINE_H
#define TRINITYSERVER_SPLINE_H

#include "MovementTypedefs.h"
#include <G3D/Vector3.h>
#include <limits>

namespace Movement {

class SplineBase
{
public:
 typedef int index_type;
 typedef std::vector<Vector3> ControlArray;

 enum EvaluationMode
 {
 ModeLinear,
 ModeCatmullrom,
 ModeBezier3_Unused,
 UninitializedMode,
 ModesEnd
 };

protected:
 ControlArray points;

 index_type index_lo;
 index_type index_hi;

 uint8 m_mode;
 bool cyclic;

 enum{
 // could be modified, affects segment length evaluation precision
 // lesser value saves more performance in cost of lover precision
 // minimal value is 1
 // client's value is 20, blizzs use 2-3 steps to compute length
 STEPS_PER_SEGMENT = 3
 };
 static_assert(STEPS_PER_SEGMENT > 0, "STEPS_PER_SEGMENT shouldn't be lesser than 1");

protected:
 void EvaluateLinear(index_type, float, Vector3&) const;
 void EvaluateCatmullRom(index_type, float, Vector3&) const;
 void EvaluateBezier3(index_type, float, Vector3&) const;
 typedef void (SplineBase::*EvaluationMethtod)(index_type, float, Vector3&) const;
 static EvaluationMethtod evaluators[ModesEnd];

 void EvaluateDerivativeLinear(index_type, float, Vector3&) const;
 void EvaluateDerivativeCatmullRom(index_type, float, Vector3&) const;
 void EvaluateDerivativeBezier3(index_type, float, Vector3&) const;
 static EvaluationMethtod derivative_evaluators[ModesEnd];

 float SegLengthLinear(index_type) const;
 float SegLengthCatmullRom(index_type) const;
 float SegLengthBezier3(index_type) const;
 typedef float (SplineBase::*SegLenghtMethtod)(index_type) const;
 static SegLenghtMethtod seglengths[ModesEnd];

 void InitLinear(const Vector3*, index_type, index_type);
 void InitCatmullRom(const Vector3*, index_type, index_type);
 void InitBezier3(const Vector3*, index_type, index_type);
 typedef void (SplineBase::*InitMethtod)(const Vector3*, index_type, index_type);
 static InitMethtod initializers[ModesEnd];

 void UninitializedSpline() const { ABORT();}

public:

 explicit SplineBase() : index_lo(0), index_hi(0), m_mode(UninitializedMode), cyclic(false) { }

 void evaluate_percent(index_type Idx, float u, Vector3& c) const {(this->*evaluators[m_mode])(Idx, u, c);}

 void evaluate_derivative(index_type Idx, float u, Vector3& hermite) const {(this->*derivative_evaluators[m_mode])(Idx, u, hermite);}

 index_type first() const { return index_lo;}
 index_type last() const { return index_hi;}

 bool empty() const { return index_lo == index_hi;}
 EvaluationMode mode() const { return (EvaluationMode)m_mode;}
 bool isCyclic() const { return cyclic;}

 const ControlArray& getPoints() const { return points; }
 index_type getPointCount() const { return index_type(points.size()); }
 const Vector3& getPoint(index_type i) const { return points[i]; }

 void init_spline(const Vector3 * controls, index_type count, EvaluationMode m);
 void init_cyclic_spline(const Vector3 * controls, index_type count, EvaluationMode m, index_type cyclic_point);

 template<class Init> inline void init_spline_custom(Init& initializer)
 {
 initializer(m_mode, cyclic, points, index_lo, index_hi);
 }

 void clear();

 float SegLength(index_type i) const { return (this->*seglengths[m_mode])(i);}

 std::string ToString() const;
};

template<typename length_type>
class Spline : public SplineBase
{
public:
 typedef length_type LengthType;
 typedef std::vector<length_type> LengthArray;
protected:

 LengthArray lengths;

 index_type computeIndexInBounds(length_type length) const;
public:

 explicit Spline(){ }

 void evaluate_percent(float t, Vector3 & c) const;

 void evaluate_derivative(float t, Vector3& hermite) const;

 void evaluate_percent(index_type Idx, float u, Vector3& c) const { SplineBase::evaluate_percent(Idx, u, c);}

 void evaluate_derivative(index_type Idx, float u, Vector3& c) const { SplineBase::evaluate_derivative(Idx, u, c);}

 // Assumes that t in range [0, 1]
 index_type computeIndexInBounds(float t) const;
 void computeIndex(float t, index_type& out_idx, float& out_u) const;

 void init_spline(const Vector3 * controls, index_type count, EvaluationMode m) { SplineBase::init_spline(controls, count, m);}
 void init_cyclic_spline(const Vector3 * controls, index_type count, EvaluationMode m, index_type cyclic_point) { SplineBase::init_cyclic_spline(controls, count, m, cyclic_point);}

 void initLengths();

 template<class T> inline void initLengths(T& cacher)
 {
 index_type i = index_lo;
 lengths.resize(index_hi+1);
 length_type prev_length = 0, new_length = 0;
 while (i < index_hi)
 {
 new_length = cacher(*this, i);
 // length overflowed, assign to max positive value
 if (new_length < 0)
 new_length = std::numeric_limits<length_type>::max();
 lengths[++i] = new_length;

 ASSERT(prev_length <= new_length);
 prev_length = new_length;
 }
 }

 length_type length() const { return lengths[index_hi];}
 length_type length(index_type first, index_type last) const { return lengths[last]-lengths[first];}
 length_type length(index_type Idx) const { return lengths[Idx];}

 void set_length(index_type i, length_type length) { lengths[i] = length;}
 void clear();
};

}

#include "SplineImpl.h"

#endif // TRINITYSERVER_SPLINE_H