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#ifndef STAN_SPRING_NETWORK_H
#define STAN_SPRING_NETWORK_H
#include "vec3n.h"
#define SPRING_STRUCT (0)
#define SPRING_SHEAR (1)
#define SPRING_BEND (2)
class SpringNetwork
{
public:
class Spring
{
public:
int type; // index into coefficients spring_k[]
float restlen;
int a,b; // spring endpoints vector indices
int iab,iba; // indices into off-diagonal blocks of sparse matrix
Spring(){}
Spring(int _type,int _a,int _b,float _restlen):type(_type),a(_a),b(_b),restlen(_restlen){iab=iba=-1;}
};
Array<Spring> springs;
float3N X; // positions of all points
float3N V; // velocities
float3N F; // force on each point
float3N dV; // change in velocity
float3Nx3N A; // big matrix we solve system with
float3Nx3N dFdX; // big matrix of derivative of force wrt position
float3Nx3N dFdV; // big matrix of derivative of force wrt velocity
float3Nx3N S; // used for our constraints - contains only some diagonal blocks as needed S[i,i]
int awake;
float3 bmin,bmax;
union
{
struct
{
float spring_struct;
float spring_shear;
float spring_bend;
};
float spring_k[3];
};
float spring_damp;
float spring_air;
float cloth_step; // delta time for cloth
float3 cloth_gravity;
float cloth_sleepthreshold;
int cloth_sleepcount;
SpringNetwork(int _n);
Spring &AddBlocks(Spring &s);
Spring &CreateSpring(int type,int a,int b,float restlen){return AddBlocks(springs.Add(Spring(type,a,b,restlen)));}
Spring &CreateSpring(int type,int a,int b){return CreateSpring(type,a,b,magnitude(X[b]-X[a]));}
void UpdateLimits() { BoxLimits(X.element,X.count,bmin,bmax);}
void Wake(){awake=cloth_sleepcount;}
void Simulate(float dt);
void PreSolveSpring(const Spring &s);
void CalcForces();
};
#endif //STAN_SPRING_NETWORK_H
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