RBD/RBD_Object.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * Produced by: 
 *      Jeff Lait
 *      Side Effects Software Inc.
 *      123 Front Street West, Suite 1401
 *      Toronto, Ontario
 *      Canada   M5J 2M2
 *      416-504-9876
 *
 * NAME:        RBD_Object.h ( RBD Library, C++)
 *
 * COMMENTS: 
 *      This holds all the data we care about for RBD Objects
 *      This allows us to avoid having to re-acquire the data
 *      in innermost loops.
 */

#ifndef __RBD_Object_H__
#define __RBD_Object_H__

#include "RBD_API.h"
#include <UT/UT_Vector3.h>
#include <UT/UT_BoundingBox.h>
#include <UT/UT_Quaternion.h>
#include <UT/UT_PtrArray.h>
#include <UT/UT_Vector3Array.h>
#include <SIM/SIM_ObjectArray.h>
#include <SIM/SIM_Solver.h>
#include <SIM/SIM_Collider.h>
#include <SIM/SIM_ObjectSolveInfo.h>
#include <GU/GU_SDF.h>
#include "RBD_SharedAffectorList.h"

class UT_HashTable;
class SIM_Object;
class SIM_Geometry;
class SIM_Engine;
class SIM_Time;
class SIM_SDF;
class SIM_Impacts;
class SIM_ConAnchorSpatial;
class RBD_Object;
class RBD_Solver;
class RBD_State;
class RBD_SphereTree;
class RBD_SpherePointTree;
class RBD_SphereEdgeTree;

typedef UT_PtrArray<RBD_Object *> RBD_ObjectArray;

class RBD_API RBD_Object : public SIM_ObjectSolveInfo
{
public:
                         RBD_Object(const SIM_Solver *solver, SIM_Object *obj);
    virtual             ~RBD_Object();

    /// These cache the common RBD structures so we don't have
    /// to look them up every time we fetch them.
    SIM_Object          *getObject() const { return myObject; }
    RBD_State           *getState() const { return myState; }
    SIM_Impacts         *getImpacts();
    const SIM_SDF       *getSDF() const { return mySDF; }
    const SIM_Geometry  *getGeometry() const { return myGeometry; }

    const RBD_SphereTree*getSphereTree() const;

    /// This is the radius of this object from the pivot position.
    /// It is thus orientation independent.
    fpreal               getRadius() const { return myRadius; }

    /// Returns true if this object can intersect anywhere in space
    /// Used for things like implicit planes.
    bool                 isInfiniteExtent() const;

    /// This returns the bounding box of the object inside it's
    /// own frame.  This must be transformed by the orientation
    /// to get the world bounding box.
    void                 getBBox(UT_BoundingBox &bbox) const;

    /// Accumulates into the  given arrays all of our point's positions
    /// and velocities.  Both are given in world space.
    void                 accumulatePointVelocity(UT_Vector3Array &pos,
                                                 UT_Vector3Array &vel) const;

    /// Stashes the current state internally.
    void                 stashState();

    /// Reloads our impact data structure from the SIM_Object.  This must
    /// be done whenever preserveImpacts is called.
    void                 reloadImpacts(
                            SIM_Collider::SIM_ImpactApplyType impactaplytype);

    /// Copies our NewImpact data into Impacts.
    /// This is a pass through to SIM_Object, but ensures our cached
    /// impact structure is cleared.
    void                 preserveImpacts(SIM_Engine *engine);

    /// Restores the position of the state using changePosition.
    void                 restoreStatePos();
    /// Restores the velocity of the state using changeVelocity.
    void                 restoreStateVel();
    /// Restores the full state
    void                 restoreState();

    /// This returns a list of all the objects that are frozen to us.
    void                 getGlueSubObjects(RBD_ObjectArray &objlist) const;

    /// Discover the number of glued subobjects and retrieve a specific
    /// one
    int                  getNumGlueSubObjects() const;
    RBD_Object          *getNthGlueSubObject(int i) const;

    /// Returns our parent object, null if not glued.
    RBD_Object          *getGlueParent() const { return myGlueParent; }

    /// This returns true if we have any frozen sub objects.
    bool                 hasGlueSubObjects() const;

    /// Marks that obj is glued to this.
    void                 addGlueSubObject(RBD_Object *obj);

    /// Removes that object as being glued to this.
    void                 removeGlueSubObject(RBD_Object *obj);

    /// Returns true if the given object is one of our glue children.
    bool                 hasAsGlueChild(RBD_Object *obj);

    /// Return if this object is glued to somewhere else.
    bool                 isGlued() const { return myIsGlued; }

    /// Builds the impulse model matrix for the given
    /// world space coordinate.  This matrix when multiplied by
    /// an impulse will give the change in velocity at that point
    /// caused by the impulse.
    /// 
    /// This takes hard constraints into consideration.
    /// Builds the impulse model matrix describing the velocity change
    /// at point p given a force at point f.
    /// This is Mfp-1 in my naming scheme.
    void                 buildImpulseModel(UT_DMatrix3 &k,
                                           const UT_Vector3 &f,
                                           const UT_Vector3 &p) const;

    /// Builds the impulse model matrix describing motion of P on *this
    /// given an a force at f on *this.
    /// This is Mzfp-1(A) in my naming scheme, where this is Z.
    void                 buildImpulseModelForA(UT_DMatrix3 &k,
                                               const UT_Vector3 &f,
                                               const UT_Vector3 &p,
                                               RBD_Object *A) const;

    /// Determines what hard constraints are present at this time
    /// step and updates its internal model to reflect theses.
    /// We need the end time to be able to acquire non-interpolated
    /// objects to handle live pin constraints.
    void                 buildConstraints(const RBD_Solver *solver,
                                          const SIM_Time &time,
                                          const SIM_Time &endtime);

    /// Removes the constraints added.  This restores stuff like the
    /// pivot to its original value.
    void                 removeConstraints();

    /// Applies an impulse to this object.
    /// This results in an instantaneous change in velocity and
    /// angular velocity.
    void                 applyImpulse(const UT_Vector3 &pos,
                                      fpreal impulse,
                                      const UT_Vector3 &normal);
    /// Applies impulses from SIM_Impacts data.
    void                 applyImpacts(const SIM_Impacts *impacts,
                                      const SIM_Time &time,
                                      const SIM_Time &timestep);

    /// Integrate position.  Uses current velocity.
    void                 integratePosition(const SIM_Time &time,
                                           const SIM_Time &timestep);
    
    /// Integrate velocity.  Finds & applies all forces.
    void                 integrateVelocity(const SIM_Time &time,
                                           const SIM_Time &timestep);

    /// Builds the SDF and updates the state from the sdf,
    /// unless sdf is already built.
    void                 initSDF();

    /// Updates the state from geometry, unless already calculated.
    void                 initFromGeometry();

    /// Calculates the radius, unless already calculated.
    void                 initRadius();

    /// Calculates the bounding box.
    void                 initBBox(bool useSDF);

    /// Gathers all of our builder requests.
    void                 gatherBuilderRequests(UT_RefArray<GU_SDFDelayedBuilder> &buildrequests);
    
    /// Initialize for collisions
    void                 initForCollisions();
    
    /// Calculates the property value at the given world position.
    fpreal               getPropertyAtPosition(
                                const SIM_Property &property, 
                                const UT_Vector3 &pos) const;

    /// Rebuilds the list of affectors for this object.
    /// Interpolates the affectors for the given time.
    void                 rebuildAffectorList(const RBD_Solver *solver,
                                SIM_Engine &engine, 
                                const SIM_Time &time,
                                const SIM_Time &timestep,
                                RBD_SharedAffectorListArray &affectorlists,
                                UT_HashTable &affectorhash);

    /// Gets the transform matrix from self to world from stashed state
    void                 getStashedTransform(UT_DMatrix4 &xform) const;

    void                 findOverlapIdx(const RBD_Solver *solver,
                                        UT_IntArray &overlap)
                         { if( mySharedAffectorList )
                               mySharedAffectorList->findOverlapIdx(solver,
                                                                    this,
                                                                    overlap);
                           else
                               overlap.entries(0); }
    void                 setAffectorTreeDirty()
                         { if( mySharedAffectorList )
                               mySharedAffectorList->setObjectTreeDirty(); }
    
    int                  getNumAffectors() const
                         { return mySharedAffectorList 
                                        ? mySharedAffectorList->entries() 
                                        : 0; }
    RBD_Object          *getAffector(int j) const
                         { return (*mySharedAffectorList)(j); }
    const SIM_Collider  *getCollider(int j) const
                         { return mySharedAffectorList->
                                        getCollider(j, myObject); }
    SIM_Collider::SIM_ImpactApplyType    getImpactApplyType(int j) const
                         { return mySharedAffectorList->getImpactApplyType(j); }

    // The array index value is used by the solver to keep track of the
    // RBD_Object's position within an array. It is a temporary value with
    // meaning only for the solver.
    int                  getArrayIndex() const
                         { return myArrayIndex; }
    void                 setArrayIndex(int index)
                         { myArrayIndex = index; }

    bool                 hasNailConstraints() const
                         { return myHasConstraints; }

    UT_PtrArray<SIM_ColliderCacheData *> &getCollideCache() { return myCollideCache; }
    void                 clearCollideCache();

    // Are we currently processing pin constraints for this object?
    mutable bool         myPinProcessFlag;
    RBD_ObjectArray      myPinObjects;

    // This is the position of the anchors.  It is stored in
    // our object space of this for AnchorPos and of myPinObjects for
    // goal pos.
    UT_Vector3Array      myPinAnchorPos;
    UT_Vector3Array      myPinAnchorGoalPos;

protected:
    // Iterates over all constraints attached to piece.  All hard
    // constraints are added to our own list of pin constraints
    // and our list of hard positions.
    // Recurses to all glued subobjects.
    void                 accumulateConstraints(const RBD_Solver *solver,
                                RBD_Object *piece,
                                UT_Vector3Array &hard_objpos,
                                UT_Vector3Array &hard_goalpos,
                                UT_Matrix3 &hard_spatialfilter,
                                UT_Matrix3 &hard_rotationalfilter,
                                const SIM_Time &time,
                                const SIM_Time &endtime);

private:
    /// Gets the property for a specific position by trying to find
    /// the closest point to that position.   The closest point will
    /// then return it's attribute value (if any) or the rbd state
    /// corresponding to that.
    /// This recurses down the glue hierarchy.
    void                 findClosestPropertyAtPosition(fpreal &newvalue,
                                    const SIM_Property &property,
                                    const UT_Vector3 &pos, 
                                    bool &found, fpreal &closestdist) const;
 
    SIM_Object                          *myObject;
    RBD_State                           *myState;
    SIM_Impacts                         *myImpacts;
    RBD_SharedAffectorList              *mySharedAffectorList;
    int                                  myArrayIndex;

    const SIM_Geometry                  *myGeometry;
    const SIM_SDF                       *mySDF;

    // Stashes whether we have these attributes & what their
    // offsets are.  -2 means not yet calculated.
    mutable GB_AttributeRef              myPropertyOffset[SIM_PROPERTY_COUNT];
    mutable bool                         myPropertyLookedUp[SIM_PROPERTY_COUNT];
    mutable const RBD_SphereTree        *mySphereTree;

    // Our radius, -1 if not yet computed.
    fpreal               myRadius;

    // Our bounding box, in local coords.
    bool                 myBBoxValid;
    UT_BoundingBox       myBBox;

    // This is where we stash our orientation.
    UT_Vector3           myStashPos;
    UT_Quaternion        myStashOrient;
    UT_Vector3           myStashVel;
    UT_Vector3           myStashAngVel;

    // Something glued will not simulate.
    bool                 myIsGlued;
    // Stores if we have constraints.
    bool                 myHasConstraints;

    // Pre-constraint values for these.
    UT_Matrix3           myCacheTensor;
    UT_Vector3           myCachePivot;
    UT_Vector3           myMomentArm;
    UT_Matrix3           mySpatialFilter;
    UT_Matrix3           myRotationalFilter;

    // This is used temporarily during the solving process to track
    // what subobjects are present.
    RBD_Object          *myGlueParent;
    RBD_ObjectArray      myGlueSubObjects;

    UT_PtrArray<SIM_ColliderCacheData *>        myCollideCache;

    bool                 myHasInitFromGeometry;
};

#endif

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