source: downloads/ogreode/include/OgreOdeFrameListener.h @ 44

/*
    PhysicsFrameListener.h

        A very simple wrapper class for ODE
        primarily for the example car application
*/
#ifndef _PHYSICSFRAMELISTENER_H_
#define _PHYSICSFRAMELISTENER_H_

// Uncomment this if you're planning to use the Plane2D joint
// But you'll have to have modified ODE first!
// #define INCLUDE_PLANE2D_JOINT

/*
A physical thing
*/
class PhysicalThing : public RaySceneQueryListener
{
public:
        // Doesn't actually do anything
        PhysicalThing(dSpace *space);
        ~PhysicalThing(void);

        // Just create geoms
    void makePlane(Real a,Real b,Real c,Real d);                                // Plane
    void makeBox(Real x,Real y,Real z,Real lx,Real ly,Real lz); // Box
    void makeSphere(Real x,Real y,Real z,Real r);                               // Sphere

        // Create bodies and geoms
    void makePlane(dWorld *world,SceneNode *node);
        void makeBox(dWorld *world,SceneNode *node,Real mass = 1,Vector3 const &offs = Vector3(0,0,0));
    void makeSphere(dWorld *world,SceneNode *node,Real mass = 1);
        void makeTerrainTriMesh(dWorld *world,SceneManager *mgr,Real grid_size,Real grid_spacing);

        // Callback functions for the ray scene query functionality
        virtual bool queryResult(SceneQuery::WorldFragment *fragment,Real distance);
        virtual bool queryResult(MovableObject *obj,Real distance);

        // Update the position and orientation of the scene node we're controlling
        void update(void);

        // Utility functions to get at internal stuff
        SceneNode *getNode(void);
        dBodyID getBodyID(void);
        dSpaceID getSpaceID(void);

protected:
        dGeom           *_geom;
        dBody           *_body;
        dSpace          *_space;
        SceneNode       *_node;

        std::list<Vector3> _frag;

        dVector3 *_vertices;
        int *_indices;
};

/*
A Frame listener that implements the physics
*/
class PhysicsFrameListener : public FrameListener
{
protected:
        // All the stuff we need for ODE
    dWorld          *world;
    dHashSpace      *space;
    dJointGroup     *contactgroup;
    dSpace          *current_space;
        bool                    paused;

        // Keep track of anything we've created
    std::list<PhysicalThing*>   things;
    std::list<dSimpleSpace*>    spaces;
        std::list<dJoint*>                      joints;
    
        // Adjustable variables
    Real total_time,step_size;
        Real k_spring,k_damper,k_tyre,k_mu,k_erp,k_cfm;

        // Utility function to find the physical thing associated with an Ogre scene node
        dBodyID getBodyID(SceneNode *node);

public:
        // Standard constructor/destructor
    PhysicsFrameListener(void);
    ~PhysicsFrameListener(void);

        // Tell us when every frame's about to be started
    bool frameStarted(const FrameEvent& evt);
        void pause(bool p = true);

        // Mainly so we can access internal stuff from the collision callback
    dWorld *getWorld(void){return world;};
    dSpace *getSpace(void){return space;};
    dJointGroup *getContactGroup(void){return contactgroup;};

        // Create things manually, no physical bodies 
        // so they won't move, but things will collide with them
    PhysicalThing *createPlane(Real a,Real b,Real c,Real d);
    PhysicalThing *createBox(Real x,Real y,Real z,Real lx,Real ly,Real lz);
    PhysicalThing *createSphere(Real x,Real y,Real z,Real r);

        // Create objects based on Ogre nodes, these nodes will then
        // come under control of the physics simulation and will move about
        // as if by magic!
        // Except for the plane, which can't actually be a physical body
        // and the trimesh which we're not going to allow to be a physical body
    PhysicalThing *createPlane(SceneNode *node);
        PhysicalThing *createBox(SceneNode *node,Real mass = 1,Vector3 const &offs = Vector3(0,0,0));
    PhysicalThing *createSphere(SceneNode *node,Real mass = 1);
        PhysicalThing *createTerrainTriMesh(SceneManager *mgr,Real grid_size,Real grid_spacing);

        // Create and activate a new space inside the standard hash space
        // Things won't collide within a space so (for example) the objects
        // that make up a car won't collide with each other
    dSimpleSpace *createSpace(void);

        // Create joints between the nodes specified
        // The order of n1/n2 does matter; n1 is what you want attaching
        // and n2 is what you want it attaching to
        dJoint *createHinge2(SceneNode *n1,SceneNode *n2,const Vector3 &suspension = Vector3(0,1,0),const Vector3 &axle = Vector3(1,0,0));
        dJoint *createHinge(SceneNode *n1,SceneNode *n2,const Vector3 &axis = Vector3(1,0,0));
        dJoint *createSlider(SceneNode *n1,SceneNode *n2,const Vector3 &axis = Vector3(0,1,0));
        dJoint *createBall(SceneNode *n1,SceneNode *n2);
#ifdef INCLUDE_PLANE2D_JOINT
        dJoint *createPlane2D(SceneNode *n);
#endif

        // Apply forces to a body under our control
        void addTorque(SceneNode *n,const Vector3 &force);

        // Set the parameters used for the CFM/ERP joint parameters
        void setSuspension(Real spring,Real damper);

        // Set the acceleration due to gravity
        void setGravity(Real g);

        // Get our constants
        Real getTyre(void){return k_tyre;};
        Real getMu(void){return k_mu;};
        Real getCFM(void){return k_cfm;};
        Real getERP(void){return k_erp;};

        // Static function for ODE to call when collisions (potentially) occur
    static void collisionCallback(void *data,dGeomID o1,dGeomID o2);
};

#endif