tgBulletContactSpringCable.h

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/*
 * Copyright © 2012, United States Government, as represented by the
 * Administrator of the National Aeronautics and Space Administration.
 * All rights reserved.
 * 
 * The NASA Tensegrity Robotics Toolkit (NTRT) v1 platform is licensed
 * under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0.
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
*/

#ifndef SRC_CORE_TG_BULLET_CONTACT_SPRING_CABLE_H_
#define SRC_CORE_TG_BULLET_CONTACT_SPRING_CABLE_H_

// NTRT
#include "core/tgBulletSpringCable.h"
// The Bullet Physics library
#include "LinearMath/btScalar.h"
#include "LinearMath/btVector3.h"
// The C++ Standard Library

#include <vector>

// Forward references
class tgWorld;
class tgBulletSpringCableAnchor;
class btRigidBody;
class btCollisionShape;
class btCompoundShape;
class btPairCachingGhostObject;
class btDynamicsWorld;

class tgBulletContactSpringCable : public tgBulletSpringCable
{
public:
                
    tgBulletContactSpringCable(btPairCachingGhostObject* ghostObject,
                                                                tgWorld& world,
                                                                const std::vector<tgBulletSpringCableAnchor*>& anchors,
                                                                double coefK,
                                                                double dampingCoefficient,
                                                                double pretension = 0.0,
                                                                double thickness = 0.001,
                                                                double resolution = 0.1);
                virtual ~tgBulletContactSpringCable();
    
    virtual void step(double dt);
    
    virtual const btScalar getActualLength() const;
    
private:
    
    struct anchorCompare
    {
        anchorCompare(const tgBulletSpringCableAnchor* m1, const tgBulletSpringCableAnchor* m2);
        
        bool operator() (const tgBulletSpringCableAnchor* lhs, const tgBulletSpringCableAnchor* rhs) const;
                                
        bool comparePoints(btVector3& pt2, btVector3& pt3) const;
        
        private:
           const tgBulletSpringCableAnchor* const ma1;
           const tgBulletSpringCableAnchor* const ma2;
    };
    
    virtual void calculateAndApplyForce(double dt);
    
    void updateManifolds();
    
    void updateAnchorList();
    
    int updateAnchorPositions();
    
    void pruneAnchors();
    
    void updateCollisionObject();
    
    void deleteCollisionShape(btCollisionShape* pShape);
    
    void clearCompoundShape(btCompoundShape* pShape);
    
    bool deleteAnchor(int i);
    
    int findNearestPastAnchor(btVector3& pos);
    
    std::vector<tgBulletSpringCableAnchor*>::iterator m_anchorIt;
    
    std::vector<tgBulletSpringCableAnchor*> m_newAnchors;
    
    tgWorld&  m_world;
    
protected:  
    
    btPairCachingGhostObject* m_ghostObject;
                
                const double m_thickness;
                
                const double m_resolution;

private:    
    bool invariant() const;
};

#endif  // SRC_CORE_TG_BULLET_CONTACT_SPRING_CABLE_H_