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/**
* @file lljointsolverrp3.h
* @brief Implementation of LLJointSolverRP3 class
*
* $LicenseInfo:firstyear=2001&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2010, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#ifndef LL_LLJOINTSOLVERRP3_H
#define LL_LLJOINTSOLVERRP3_H
//-----------------------------------------------------------------------------
// Header Files
//-----------------------------------------------------------------------------
#include "lljoint.h"
/* -some compilers don't like line continuation chars-
//-----------------------------------------------------------------------------
// class LLJointSolverRP3
//
// This class is a "poor man's" IK for simple 3 joint kinematic chains.
// It is modeled after the 'ikRPSolver' in Maya.
// This class takes 4 LLJoints:
// jointA
// jointB
// jointC
// jointGoal
//
// Such that jointA is the parent of jointB, jointB is the parent of jointC.
// When invoked, this class modifies the rotations of jointA and jointB such
// that the position of the jointC attempts to reach the position of jointGoal.
//
// At object initialization time, the distances between jointA - jointB and
// jointB - jointC are cached. During evaluation these bone lengths are
// preserved.
//
// A A
// | |
// | |
// B B---CG A---B---C...G
// \
// \
// CG
//
//
// In addition a "poleVector" is specified that does two things:
//
// a) defines the plane in which the solution occurs, thus
// reducing an infinite number of solutions, down to 2.
//
// b) disambiguates the resulting two solutions as follows:
//
// A A A--->poleVector
// | \ \
// | \ \
// B vs. B ==> B
// \ | |
// \ | |
// CG CG CG
//
// A "twist" setting allows the solution plane to be rotated about the
// line between A and C. A handy animation feature.
//
// For "smarter" results for non-coplanar limbs, specify the joints axis
// of bend in the B's local frame (see setBAxis())
//-----------------------------------------------------------------------------
*/
class LLJointSolverRP3
{
protected:
LLJoint *mJointA;
LLJoint *mJointB;
LLJoint *mJointC;
LLJoint *mJointGoal;
F32 mLengthAB;
F32 mLengthBC;
LLVector3 mPoleVector;
LLVector3 mBAxis;
bool mbUseBAxis;
F32 mTwist;
bool mFirstTime;
LLMatrix4 mSavedJointAMat;
LLMatrix4 mSavedInvPlaneMat;
LLQuaternion mJointABaseRotation;
LLQuaternion mJointBBaseRotation;
public:
//-------------------------------------------------------------------------
// Constructor/Destructor
//-------------------------------------------------------------------------
LLJointSolverRP3();
virtual ~LLJointSolverRP3();
//-------------------------------------------------------------------------
// setupJoints()
// This must be called one time to setup the solver.
// This must be called AFTER the skeleton has been created, all parent/child
// relationships are established, and after the joints are placed in
// a valid configuration (as distances between them will be cached).
//-------------------------------------------------------------------------
void setupJoints( LLJoint* jointA,
LLJoint* jointB,
LLJoint* jointC,
LLJoint* jointGoal );
//-------------------------------------------------------------------------
// getPoleVector()
// Returns the current pole vector.
//-------------------------------------------------------------------------
const LLVector3& getPoleVector();
//-------------------------------------------------------------------------
// setPoleVector()
// Sets the pole vector.
// The pole vector is defined relative to (in the space of) jointA's parent.
// The default pole vector is (1,0,0), and this is used if this function
// is never called.
// This vector is normalized when set.
//-------------------------------------------------------------------------
void setPoleVector( const LLVector3& poleVector );
//-------------------------------------------------------------------------
// setBAxis()
// Sets the joint's axis in B's local frame, and enable "smarter" solve().
// This allows for smarter IK when for twisted limbs.
//-------------------------------------------------------------------------
void setBAxis( const LLVector3& bAxis );
//-------------------------------------------------------------------------
// getTwist()
// Returns the current twist in radians.
//-------------------------------------------------------------------------
F32 getTwist();
//-------------------------------------------------------------------------
// setTwist()
// Sets the twist value.
// The default is 0.0.
//-------------------------------------------------------------------------
void setTwist( F32 twist );
//-------------------------------------------------------------------------
// solve()
// This is the "work" function.
// When called, the rotations of jointA and jointB will be modified
// such that jointC attempts to reach jointGoal.
//-------------------------------------------------------------------------
void solve();
};
#endif // LL_LLJOINTSOLVERRP3_H
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