Spline.h

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/*
 * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef TRINITYSERVER_SPLINE_H
#define TRINITYSERVER_SPLINE_H
 
#include "MovementTypedefs.h"
#include "Errors.h"
#include <G3D/Vector3.h>
#include <limits>
#include <vector>
 
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;
    float initialOrientation;
 
    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(Vector3 const*, index_type, index_type);
    void InitCatmullRom(Vector3 const*, index_type, index_type);
    void InitBezier3(Vector3 const*, index_type, index_type);
    typedef void (SplineBase::*InitMethtod)(Vector3 const*, index_type, index_type);
    static InitMethtod initializers[ModesEnd];
 
    void UninitializedSplineEvaluationMethod(index_type, float, Vector3&) const { ABORT(); }
    float UninitializedSplineSegLenghtMethod(index_type) const { ABORT(); return 0.0f; }
    void UninitializedSplineInitMethod(Vector3 const*, index_type, index_type) { ABORT(); }
 
public:
 
    explicit SplineBase() : index_lo(0), index_hi(0), m_mode(UninitializedMode), cyclic(false), initialOrientation(0.f) { }
 
    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;}
 
    ControlArray const& getPoints() const { return points;}
    index_type getPointCount() const { return points.size();}
    Vector3 const& getPoint(index_type i) const { return points[i];}
 
    void init_spline(const Vector3 * controls, index_type count, EvaluationMode m, float orientation);
    void init_cyclic_spline(const Vector3 * controls, index_type count, EvaluationMode m, index_type cyclic_point, float orientation);
 
    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, float orientation = 0) { SplineBase::init_spline(controls, count, m, orientation);}
    void init_cyclic_spline(const Vector3 * controls, index_type count, EvaluationMode m, index_type cyclic_point, float orientation = 0) { SplineBase::init_cyclic_spline(controls, count, m, cyclic_point, orientation);}
 
    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
    {
        if (lengths.empty())
            return 0;
        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