RBD_Solver.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.
 *
 */

#ifndef __RBD_Solver__
#define __RBD_Solver__

#include "RBD_API.h"

#include <SIM/SIM_Collider.h>
#include <SIM/SIM_Isect.h>
#include <SIM/SIM_OptionsUser.h>
#include <SIM/SIM_Solver.h>
#include <GU/GU_SDF.h>

#include "RBD_Object.h"
#include "RBD_Utils.h"

class SIM_Object;
class SIM_Random;
class SIM_SDF;
class RBD_State;
class RBD_ContactGraph;
class RBD_ObjectTree;


#define RBD_NAME_COLLISIONITERATIONS    "collisioniterations"
#define RBD_NAME_CONTACTITERATIONS      "contactiterations"
#define RBD_NAME_SUBCONTACTITERATIONS   "subcontactiterations"
#define RBD_NAME_SHOCKPROPAGATION       "shockpropagation"
#define RBD_NAME_USEEDGES               "useedges"
#define RBD_NAME_FLAGPENETRATION        "flagpenetration"
#define RBD_NAME_MINIMUMSUBSTEPS        "minimumsubsteps"
#define RBD_NAME_MAXIMUMSUBSTEPS        "maximumsubsteps"
#define RBD_NAME_CFLCOND                "cflcond"
#define RBD_NAME_RESOLVEPENETRATION     "resolvepenetration"
#define RBD_NAME_GLUEIGNORESRESTING     "glueignoresrestingobjects"

/// This is a RBD-RBD meta solver.  It handles the cases where
/// RBD objects have a Mutual affect relationship with each other.
class RBD_API RBD_Solver : public SIM_Solver,
                              public SIM_OptionsUser
{
public:
    GETSET_DATA_FUNCS_I(RBD_NAME_COLLISIONITERATIONS, CollisionIterations)
    GETSET_DATA_FUNCS_I(RBD_NAME_CONTACTITERATIONS, ContactIterations)
    GETSET_DATA_FUNCS_I(RBD_NAME_SUBCONTACTITERATIONS, SubContactIterations)
    GETSET_DATA_FUNCS_I(RBD_NAME_SHOCKPROPAGATION, ShockPropagation)
    GETSET_DATA_FUNCS_I(RBD_NAME_RESOLVEPENETRATION, ResolvePenetrations)
    GETSET_DATA_FUNCS_B(RBD_NAME_FLAGPENETRATION, FlagPenetration);
    GETSET_DATA_FUNCS_B(RBD_NAME_GLUEIGNORESRESTING, GlueIgnoresRestingObjects);
    GETSET_DATA_FUNCS_B(RBD_NAME_USEPOINTVELOCITY, UsePointVelocity);
    GETSET_DATA_FUNCS_B(RBD_NAME_USESDFVELOCITY, UseSDFVelocity);
    GETSET_DATA_FUNCS_I(RBD_NAME_CULLMODE, CullMode);

    GETSET_DATA_FUNCS_B(RBD_NAME_ADDIMPACTS, AddImpacts);
    GETSET_DATA_FUNCS_I(RBD_NAME_CONTACTGROUPMETHOD, ContactGroupMethod);
    GETSET_DATA_FUNCS_F(RBD_NAME_CONTACTGROUPTOL, ContactGroupTol);

    GET_DATA_FUNC_I(RBD_NAME_MINIMUMSUBSTEPS, MinimumSubSteps);
    GET_DATA_FUNC_I(RBD_NAME_MAXIMUMSUBSTEPS, MaximumSubSteps);
    GET_DATA_FUNC_F(RBD_NAME_CFLCOND, CFLCond);
    
    /// This is public as we need it in our contact graph builder.
    bool         doObjectsCollide(RBD_Object *obja, 
                                  RBD_Object *objb, 
                                  const SIM_Time &time, 
                                  const SIM_Time &timestep) const;
    
    /// This method creates an RBD_ObjectTree of the type requested
    /// by our cull mode.
    RBD_ObjectTree      *createObjectTree() const;

    /// Takes the solve info attached to the object, checks to
    /// see if it was created by us, if so, casts to RBD_Object
    /// and returns.  Can return null if the object wasn't initialized
    /// or was done with another solver.
    RBD_Object          *convertToRBDObject(const SIM_Object *obj) const;

    /// This should be kept in sync with the contact group method
    /// menu.
    enum rbdContactGroupMethod
    {
        CONTACTGROUP_NONE = 0,
        CONTACTGROUP_CLOSESTPOINT,
        CONTACTGROUP_AVERAGE
    };
    
protected:
    explicit             RBD_Solver(const SIM_DataFactory *factory);
                        ~RBD_Solver() override;

    SIM_Result           solveObjectsSubclass(SIM_Engine &engine,
                                SIM_ObjectArray &objects,
                                SIM_ObjectArray &newobjects,
                                SIM_ObjectArray &feedbacktoobjects,
                                const SIM_Time &timestep) override;
    void                 getImpulseMassMatrixSubclass(
                                const SIM_Object &object,
                                const UT_Vector3 &impulseworldpos,
                                UT_DMatrix3 &immatrix) const override;
    void                 getPointImpulseMassMatrixSubclass(
                                const SIM_Object &object,
                                int ptnum,
                                UT_DMatrix3 &immatrix) const override;
    fpreal               getPropertyAtPositionSubclass(const SIM_Object &object,
                                const UT_Vector3 &worldspacepos,
                                const SIM_Property &property) const override;
    fpreal               getPropertyAtPointSubclass(const SIM_Object &object,
                                int ptnum,
                                const SIM_Property &property) const override;
    void                 getDefaultColliderLabelSubclass(
                                const SIM_Object &object,
                                UT_String &label) const override;
    void                 getDefaultColliderSubclass(
                                const SIM_Object &object,
                                const UT_String &colliderlabel,
                                UT_String &collidertype,
                                bool &colliderreverseobjectroles
                                ) const override;

private:
    static const SIM_DopDescription *getSolverRBDDopDescription();

    /// Get a property value by looking at the RBD_State of an object.
    fpreal              getPropertyFromState(const SIM_Object &object,
                                const SIM_Property &property) const;

    /// Applies the stacking solver.
    void                solveStackObjects(SIM_ObjectArray &objects,
                                SIM_ObjectArray &newobjects,
                                const SIM_Time &time,
                                const SIM_Time &timestep);

    // Stack solving methods:

    /// Creates a SIM_Random data on all the objects in the array. This
    /// data is used by the stack solver.
    SIM_Random          *createRandomData();

    /// Resolve contact forces.
    /// Returns true if any contact forces occurred.
    bool                resolveContactForces(const RBD_ContactGraph &graph,
                                    const RBD_ObjectArray &objects,
                                    const SIM_Time &time,
                                    const SIM_Time &timestep,
                                    bool applyshock) const;

    /// Resolve actual penetration.
    /// Attempts to jiggle objects so they do not penetrate at all.
    /// All updates are done purely on position.  Penetration ignores
    /// velocity (so two objects moving apart, but overlapping, will
    /// be jiggled)
    /// The contact graph is used to provide a hierarchy for the resolution
    /// Returns true if any jiggling occurred.
    bool                resolvePenetrations(const RBD_ContactGraph &graph,
                                    const UT_ValArray<RBD_Object *> &objects,
                                    const SIM_Time &time,
                                    const SIM_Time &timestep) const;

    /// Fixes any penetrations between obj & rest by moving obj so that
    /// they no longer penetrate.  Returns true if any change occurred.
    /// Restitution is what percentage to move them.
    bool                fixPenetrations(RBD_Object *obj, RBD_Object *rest,
                                    const SIM_Collider *collider,
                                    fpreal restitution,
                                    const SIM_Time time,
                                    const SIM_Time timestep) const;
                                    
    /// Resolve elastic object collisions.
    /// Returns true if there were any elastic collisions.
    bool                resolveElasticCollisions(RBD_ObjectArray &objects,
                                    const SIM_Time &time,
                                    const SIM_Time &timestep) const;

    /// Applies forces to all of our pins so as to ensure they
    /// have no relative velocity.
    void                 resolvePinConstraintVelocities(RBD_Object *obj) const;

    /// Moves all of our pinned objects so they satisfy their
    /// pin constraints.
    /// This is done in a shock propagation style manner - a, possibly
    /// arbitrary, hierarchy is setup and each object is satisfied in
    /// turn, treating previous objects as locked.
    void                 shockPropagatePinConstraints(const RBD_ObjectArray &objects) const;
    
    /// Collide two objects elastically.  Ignores rest of world,
    /// applies impulses until each intersecting point is seperating
    /// at least once.
    /// infinitemass set to true treats object b as infinite mass,
    /// even if it actually has finite mass.
    bool         elasticCollide(RBD_Object *obj_a, RBD_Object *obj_b,
                        bool infinitemass,
                        fpreal restitution,
                        bool onlyfirst,
                        bool usebounce,
                        const SIM_Time time,
                        const SIM_Time timestep,
                        const SIM_Collider *collider,
                        SIM_Collider::SIM_ImpactApplyType affectortype) const;

    /// Extracts the next SIM_Isect from the queue.  Uses the contact
    /// grouping method to merge contacts of similar depth.
    SIM_Isect           *groupContacts(SIM_IsectPriorityQueue &queue, 
                                        RBD_Object *obj_a,
                                        RBD_Object *obj_b,
                                        bool infinitemass) const;

    /// Given a point of intersection, find and apply the impulse
    /// required to cause the point to be seperating.  (If it is
    /// already seperating, ignore)
    bool                collidePoint(RBD_Object *obj_a, RBD_Object *obj_b,
                                    bool infinitemass,
                                    const SIM_Isect *isect,
                                    fpreal restitution,
                                    bool usebounce,
                                    const SIM_Time curtime,
                                    bool usesdfvel,
                                    bool usepointvel,
                                    int child_id_a = -1,
                                    int child_id_b = -1) const;

    /// Determines the possible frozen sub object that is closest
    /// to the given point in the SDF sense.
    /// Returns true if a new closest child is found.
    /// If onlytoplevel is true, the only possible objects returned
    /// are the original obj or its children.  Subobjects are still
    /// tested, but their respective parent inherits ownership.
    bool                 findClosestChild(RBD_Object *obj, 
                                    const UT_Vector3 &pos,
                                    RBD_Object *&closest, fpreal &mindist,
                                    bool onlytoplevel = false,
                                    int child_id = -1) const;
    
    /// Given an impulse and position, applies the impulse to the
    /// object.  This is used for collision impulses.  The idea is
    /// that by sending them through this interface we can track
    /// what impulses have been applied to the object.
    /// The opposite impulse will be sent to object b, if it is given.
    /// restingcollision is set if this is a result of objects resting
    /// on each other rather than elastically colliding.
    void                 applyCollisionImpulse(RBD_Object *obj_a,
                                    RBD_Object *obj_b,
                                    int obj_b_id,
                                    fpreal scale,
                                    const UT_Vector3 &pos,
                                    const UT_Vector3 &impulse,
                                    const SIM_Time curtime,
                                    int child_id_a, 
                                    int child_id_b,
                                    bool infiniteforceVSinfinitemass,
                                    bool restingcollision) const;

    /// Adds the given impact to the SIM_Impact list for the given
    /// pair of objects.
    /// The given impulse vector does not have to be normalized.
    void                 addImpactData(RBD_Object *obj_a,
                                    RBD_Object *obj_b,
                                    int obj_b_id,
                                    const UT_Vector3 &pos,
                                    const UT_Vector3 &nml,
                                    fpreal strength,
                                    const SIM_Time curtime,
                                    bool restingcollision) const;

    /// Collide two objects using the collideObjects() from the collider
    bool          collideObjects (RBD_Object *obj_a, RBD_Object *obj_b,
                        const SIM_Time startTime,
                        const SIM_Time endTime,
                        SIM_Collider::SIM_ImpactApplyType affectortype) const;
    
    SIM_Time             getCurSolveTime() const
                         { return myCurSolveTime; }
    void                 setCurSolveTime(SIM_Time time)
                         { myCurSolveTime = time; }
    SIM_Time             getCurSolveStep() const
                         { return myCurSolveStep; }
    void                 setCurSolveStep(SIM_Time step)
                         { myCurSolveStep = step; }

    bool                 doAddImpacts() const
                         { return myAddImpacts; }
    bool                 doGlueIgnoresResting() const
                         { return myGlueIgnoresResting; }

    DECLARE_STANDARD_GETCASTTOTYPE();
    DECLARE_DATAFACTORY(RBD_Solver,
                        SIM_Solver,
                        "RBD Solver",
                        getSolverRBDDopDescription());

private:
    // Flag variables used during the simulation

    /// Flags if anything broke during the simulation.  Lets us know
    /// we need to rebuild topology dependent constructs.
    mutable bool                myBreakOccurred;

    /// Determins if we should add SIM_Impact data for every 
    /// collision we process.
    /// This is done to avoid possibly expensive parameter evaluation
    /// in deeply nested functions.
    mutable bool                myAddImpacts;
    mutable bool                myGlueIgnoresResting;

    /// Current solve time.
    SIM_Time                    myCurSolveTime;
    SIM_Time                    myCurSolveStep;

    SIM_Engine                  *myEngine;
};

#endif