text: /*
  Bullet Continuous Collision Detection and Physics Library
  Copyright (c) 2003-2010 Erwin Coumans  http://continuousphysics.com/Bullet/
  
  This software is provided 'as-is', without any express or implied warranty.
  In no event will the authors be held liable for any damages arising from the use of this software.
  Permission is granted to anyone to use this software for any purpose, 
  including commercial applications, and to alter it and redistribute it freely, 
  subject to the following restrictions:
  
  1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
  */
  
  #ifndef BT_TYPED_CONSTRAINT_H
  #define BT_TYPED_CONSTRAINT_H
  
  
  #include "LinearMath/btScalar.h"
  #include "btSolverConstraint.h"
  #include "BulletDynamics/Dynamics/btRigidBody.h"
  
  #ifdef BT_USE_DOUBLE_PRECISION
  #define btTypedConstraintData2      btTypedConstraintDoubleData
  #define btTypedConstraintDataName   "btTypedConstraintDoubleData"
  #else
  #define btTypedConstraintData2      btTypedConstraintFloatData
  #define btTypedConstraintDataName  "btTypedConstraintFloatData" 
  #endif //BT_USE_DOUBLE_PRECISION
  
  
  class btSerializer;
  
  //Don't change any of the existing enum values, so add enum types at the end for serialization compatibility
  enum btTypedConstraintType
  {
      POINT2POINT_CONSTRAINT_TYPE=3,
      HINGE_CONSTRAINT_TYPE,
      CONETWIST_CONSTRAINT_TYPE,
      D6_CONSTRAINT_TYPE,
      SLIDER_CONSTRAINT_TYPE,
      CONTACT_CONSTRAINT_TYPE,
      D6_SPRING_CONSTRAINT_TYPE,
      GEAR_CONSTRAINT_TYPE,
      FIXED_CONSTRAINT_TYPE,
      D6_SPRING_2_CONSTRAINT_TYPE,
      MAX_CONSTRAINT_TYPE
  };
  
  
  enum btConstraintParams
  {
      BT_CONSTRAINT_ERP=1,
      BT_CONSTRAINT_STOP_ERP,
      BT_CONSTRAINT_CFM,
      BT_CONSTRAINT_STOP_CFM
  };
  
  #if 1
      #define btAssertConstrParams(_par) btAssert(_par) 
  #else
      #define btAssertConstrParams(_par)
  #endif
  
  
  ATTRIBUTE_ALIGNED16(struct) btJointFeedback
  {
      BT_DECLARE_ALIGNED_ALLOCATOR();
      btVector3   m_appliedForceBodyA;
      btVector3   m_appliedTorqueBodyA;
      btVector3   m_appliedForceBodyB;
      btVector3   m_appliedTorqueBodyB;
  };
  
  
  ///TypedConstraint is the baseclass for Bullet constraints and vehicles
  ATTRIBUTE_ALIGNED16(class) btTypedConstraint : public btTypedObject
  {
      int m_userConstraintType;
  
      union
      {
          int m_userConstraintId;
          void* m_userConstraintPtr;
      };
  
      btScalar    m_breakingImpulseThreshold;
      bool        m_isEnabled;
      bool        m_needsFeedback;
      int         m_overrideNumSolverIterations;
  
  
      btTypedConstraint&  operator=(btTypedConstraint&    other)
      {
          btAssert(0);
          (void) other;
          return *this;
      }
  
  protected:
      btRigidBody&    m_rbA;
      btRigidBody&    m_rbB;
      btScalar    m_appliedImpulse;
      btScalar    m_dbgDrawSize;
      btJointFeedback*    m_jointFeedback;
  
      ///internal method used by the constraint solver, don't use them directly
      btScalar getMotorFactor(btScalar pos, btScalar lowLim, btScalar uppLim, btScalar vel, btScalar timeFact);
      
  
  public:
  
      BT_DECLARE_ALIGNED_ALLOCATOR();
  
      virtual ~btTypedConstraint() {};
      btTypedConstraint(btTypedConstraintType type, btRigidBody& rbA);
      btTypedConstraint(btTypedConstraintType type, btRigidBody& rbA,btRigidBody& rbB);
  
      struct btConstraintInfo1 {
          int m_numConstraintRows,nub;
      };
  
      static btRigidBody& getFixedBody();
  
      struct btConstraintInfo2 {
          // integrator parameters: frames per second (1/stepsize), default error
          // reduction parameter (0..1).
          btScalar fps,erp;
  
          // for the first and second body, pointers to two (linear and angular)
          // n*3 jacobian sub matrices, stored by rows. these matrices will have
          // been initialized to 0 on entry. if the second body is zero then the
          // J2xx pointers may be 0.
          btScalar *m_J1linearAxis,*m_J1angularAxis,*m_J2linearAxis,*m_J2angularAxis;
  
          // elements to jump from one row to the next in J's
          int rowskip;
  
          // right hand sides of the equation J*v = c + cfm * lambda. cfm is the
          // "constraint force mixing" vector. c is set to zero on entry, cfm is
          // set to a constant value (typically very small or zero) value on entry.
          btScalar *m_constraintError,*cfm;
  
          // lo and hi limits for variables (set to -/+ infinity on entry).
          btScalar *m_lowerLimit,*m_upperLimit;
  
          // number of solver iterations
          int m_numIterations;
  
          //damping of the velocity
          btScalar    m_damping;
      };
  
      int getOverrideNumSolverIterations() const
      {
          return m_overrideNumSolverIterations;
      }
  
      ///override the number of constraint solver iterations used to solve this constraint
      ///-1 will use the default number of iterations, as specified in SolverInfo.m_numIterations
      void setOverrideNumSolverIterations(int overideNumIterations)
      {
          m_overrideNumSolverIterations = overideNumIterations;
      }
  
      ///internal method used by the constraint solver, don't use them directly
      virtual void    buildJacobian() {};
  
      ///internal method used by the constraint solver, don't use them directly
      virtual void    setupSolverConstraint(btConstraintArray& ca, int solverBodyA,int solverBodyB, btScalar timeStep)
      {
          (void)ca;
          (void)solverBodyA;
          (void)solverBodyB;
          (void)timeStep;
      }
      
      ///internal method used by the constraint solver, don't use them directly
      virtual void getInfo1 (btConstraintInfo1* info)=0;
  
      ///internal method used by the constraint solver, don't use them directly
      virtual void getInfo2 (btConstraintInfo2* info)=0;
  
      ///internal method used by the constraint solver, don't use them directly
      void    internalSetAppliedImpulse(btScalar appliedImpulse)
      {
          m_appliedImpulse = appliedImpulse;
      }
      ///internal method used by the constraint solver, don't use them directly
      btScalar    internalGetAppliedImpulse()
      {
          return m_appliedImpulse;
      }
  
  
      btScalar    getBreakingImpulseThreshold() const
      {
          return  m_breakingImpulseThreshold;
      }
  
      void    setBreakingImpulseThreshold(btScalar threshold)
      {
          m_breakingImpulseThreshold = threshold;
      }
  
      bool    isEnabled() const
      {
          return m_isEnabled;
      }
  
      void    setEnabled(bool enabled)
      {
          m_isEnabled=enabled;
      }
  
  
      ///internal method used by the constraint solver, don't use them directly
      virtual void    solveConstraintObsolete(btSolverBody& /*bodyA*/,btSolverBody& /*bodyB*/,btScalar    /*timeStep*/) {};
  
      
      const btRigidBody& getRigidBodyA() const
      {
          return m_rbA;
      }
      const btRigidBody& getRigidBodyB() const
      {
          return m_rbB;
      }
  
      btRigidBody& getRigidBodyA() 
      {
          return m_rbA;
      }
      btRigidBody& getRigidBodyB()
      {
          return m_rbB;
      }
  
      int getUserConstraintType() const
      {
          return m_userConstraintType ;
      }
  
      void    setUserConstraintType(int userConstraintType)
      {
          m_userConstraintType = userConstraintType;
      };
  
      void    setUserConstraintId(int uid)
      {
          m_userConstraintId = uid;
      }
  
      int getUserConstraintId() const
      {
          return m_userConstraintId;
      }
  
      void    setUserConstraintPtr(void* ptr)
      {
          m_userConstraintPtr = ptr;
      }
  
      void*   getUserConstraintPtr()
      {
          return m_userConstraintPtr;
      }
  
      void    setJointFeedback(btJointFeedback* jointFeedback)
      {
          m_jointFeedback = jointFeedback;
      }
  
      const btJointFeedback* getJointFeedback() const
      {
          return m_jointFeedback;
      }
  
      btJointFeedback* getJointFeedback()
      {
          return m_jointFeedback;
      }
  
  
      int getUid() const
      {
          return m_userConstraintId;   
      } 
  
      bool    needsFeedback() const
      {
          return m_needsFeedback;
      }
  
      ///enableFeedback will allow to read the applied linear and angular impulse
      ///use getAppliedImpulse, getAppliedLinearImpulse and getAppliedAngularImpulse to read feedback information
      void    enableFeedback(bool needsFeedback)
      {
          m_needsFeedback = needsFeedback;
      }
  
      ///getAppliedImpulse is an estimated total applied impulse. 
      ///This feedback could be used to determine breaking constraints or playing sounds.
      btScalar    getAppliedImpulse() const
      {
          btAssert(m_needsFeedback);
          return m_appliedImpulse;
      }
  
      btTypedConstraintType getConstraintType () const
      {
          return btTypedConstraintType(m_objectType);
      }
      
      void setDbgDrawSize(btScalar dbgDrawSize)
      {
          m_dbgDrawSize = dbgDrawSize;
      }
      btScalar getDbgDrawSize()
      {
          return m_dbgDrawSize;
      }
  
      ///override the default global value of a parameter (such as ERP or CFM), optionally provide the axis (0..5). 
      ///If no axis is provided, it uses the default axis for this constraint.
      virtual void    setParam(int num, btScalar value, int axis = -1) = 0;
  
      ///return the local value of parameter
      virtual btScalar getParam(int num, int axis = -1) const = 0;
      
      virtual int calculateSerializeBufferSize() const;
  
      ///fills the dataBuffer and returns the struct name (and 0 on failure)
      virtual const char* serialize(void* dataBuffer, btSerializer* serializer) const;
  
  };
  
  // returns angle in range [-SIMD_2_PI, SIMD_2_PI], closest to one of the limits 
  // all arguments should be normalized angles (i.e. in range [-SIMD_PI, SIMD_PI])
  SIMD_FORCE_INLINE btScalar btAdjustAngleToLimits(btScalar angleInRadians, btScalar angleLowerLimitInRadians, btScalar angleUpperLimitInRadians)
  {
      if(angleLowerLimitInRadians >= angleUpperLimitInRadians)
      {
          return angleInRadians;
      }
      else if(angleInRadians < angleLowerLimitInRadians)
      {
          btScalar diffLo = btFabs(btNormalizeAngle(angleLowerLimitInRadians - angleInRadians));
          btScalar diffHi = btFabs(btNormalizeAngle(angleUpperLimitInRadians - angleInRadians));
          return (diffLo < diffHi) ? angleInRadians : (angleInRadians + SIMD_2_PI);
      }
      else if(angleInRadians > angleUpperLimitInRadians)
      {
          btScalar diffHi = btFabs(btNormalizeAngle(angleInRadians - angleUpperLimitInRadians));
          btScalar diffLo = btFabs(btNormalizeAngle(angleInRadians - angleLowerLimitInRadians));
          return (diffLo < diffHi) ? (angleInRadians - SIMD_2_PI) : angleInRadians;
      }
      else
      {
          return angleInRadians;
      }
  }
  
  ///do not change those serialization structures, it requires an updated sBulletDNAstr/sBulletDNAstr64
  struct  btTypedConstraintFloatData
  {
      btRigidBodyFloatData        *m_rbA;
      btRigidBodyFloatData        *m_rbB;
      char    *m_name;
  
      int m_objectType;
      int m_userConstraintType;
      int m_userConstraintId;
      int m_needsFeedback;
  
      float   m_appliedImpulse;
      float   m_dbgDrawSize;
  
      int m_disableCollisionsBetweenLinkedBodies;
      int m_overrideNumSolverIterations;
  
      float   m_breakingImpulseThreshold;
      int     m_isEnabled;
      
  };
  
  ///do not change those serialization structures, it requires an updated sBulletDNAstr/sBulletDNAstr64
  
  #define BT_BACKWARDS_COMPATIBLE_SERIALIZATION
  #ifdef BT_BACKWARDS_COMPATIBLE_SERIALIZATION
  ///this structure is not used, except for loading pre-2.82 .bullet files
  struct  btTypedConstraintData
  {
      btRigidBodyData     *m_rbA;
      btRigidBodyData     *m_rbB;
      char    *m_name;
  
      int m_objectType;
      int m_userConstraintType;
      int m_userConstraintId;
      int m_needsFeedback;
  
      float   m_appliedImpulse;
      float   m_dbgDrawSize;
  
      int m_disableCollisionsBetweenLinkedBodies;
      int m_overrideNumSolverIterations;
  
      float   m_breakingImpulseThreshold;
      int     m_isEnabled;
      
  };
  #endif //BACKWARDS_COMPATIBLE
  
  struct  btTypedConstraintDoubleData
  {
      btRigidBodyDoubleData       *m_rbA;
      btRigidBodyDoubleData       *m_rbB;
      char    *m_name;
  
      int m_objectType;
      int m_userConstraintType;
      int m_userConstraintId;
      int m_needsFeedback;
  
      double  m_appliedImpulse;
      double  m_dbgDrawSize;
  
      int m_disableCollisionsBetweenLinkedBodies;
      int m_overrideNumSolverIterations;
  
      double  m_breakingImpulseThreshold;
      int     m_isEnabled;
      char    padding[4];
      
  };
  
  
  SIMD_FORCE_INLINE   int btTypedConstraint::calculateSerializeBufferSize() const
  {
      return sizeof(btTypedConstraintData2);
  }
  
  
  
  class btAngularLimit
  {
  private:
      btScalar 
          m_center,
          m_halfRange,
          m_softness,
          m_biasFactor,
          m_relaxationFactor,
          m_correction,
          m_sign;
  
      bool
          m_solveLimit;
  
  public:
      /// Default constructor initializes limit as inactive, allowing free constraint movement
      btAngularLimit()
          :m_center(0.0f),
          m_halfRange(-1.0f),
          m_softness(0.9f),
          m_biasFactor(0.3f),
          m_relaxationFactor(1.0f),
          m_correction(0.0f),
          m_sign(0.0f),
          m_solveLimit(false)
      {}
  
      /// Sets all limit's parameters.
      /// When low > high limit becomes inactive.
      /// When high - low > 2PI limit is ineffective too becouse no angle can exceed the limit
      void set(btScalar low, btScalar high, btScalar _softness = 0.9f, btScalar _biasFactor = 0.3f, btScalar _relaxationFactor = 1.0f);
  
      /// Checks conastaint angle against limit. If limit is active and the angle violates the limit
      /// correction is calculated.
      void test(const btScalar angle);
  
      /// Returns limit's softness
      inline btScalar getSoftness() const
      {
          return m_softness;
      }
  
      /// Returns limit's bias factor
      inline btScalar getBiasFactor() const
      {
          return m_biasFactor;
      }
  
      /// Returns limit's relaxation factor
      inline btScalar getRelaxationFactor() const
      {
          return m_relaxationFactor;
      }
  
      /// Returns correction value evaluated when test() was invoked 
      inline btScalar getCorrection() const
      {
          return m_correction;
      }
  
      /// Returns sign value evaluated when test() was invoked 
      inline btScalar getSign() const
      {
          return m_sign;
      }
  
      /// Gives half of the distance between min and max limit angle
      inline btScalar getHalfRange() const
      {
          return m_halfRange;
      }
  
      /// Returns true when the last test() invocation recognized limit violation
      inline bool isLimit() const
      {
          return m_solveLimit;
      }
  
      /// Checks given angle against limit. If limit is active and angle doesn't fit it, the angle
      /// returned is modified so it equals to the limit closest to given angle.
      void fit(btScalar& angle) const;
  
      /// Returns correction value multiplied by sign value
      btScalar getError() const;
  
      btScalar getLow() const;
  
      btScalar getHigh() const;
  
  };
  
  
  
  #endif //BT_TYPED_CONSTRAINT_H
  