SPHSimulation.h

#ifndef BRAVE2_SPHSIMULATION_H
#define BRAVE2_SPHSIMULATION_H

#include "../utils/math.h"
#include "../utils/util.h"
#include "../objects/Particle.h"
#include "Geometry.h"

namespace sph {
    // external (gravitational force)
    const static vec3 G(0.f, -9.8f, 0.f);
    // rest density
    const static float REST_DENS = 1000.0f;
    // const for equation of state
    const static float GAS_CONST = 3.0f;
    // kernel radius
    const static float H = 0.0457f;
    // (kernel radius)^2 for optimization
    const static float H2 = H * H;
    // mass of particles
    const static float M = 0.02f;
    // viscosity constant
    const static float MU = 42.f;
    // TODO decide the place for this
    // integration timestep
    const static float DT = 0.01f;

    // epsilon (e.g. at boundary check)
    const static float EPS = 0.0001f;
    // damping when colliding with the boundary
    const static float BOUND_DAMPING = -0.5f;

    [[maybe_unused]] const static float PI = 3.1415926535f;
    // smoothing kernel as described in the Müller paper
    const static float POLY6 = 315.f / (64.f * PI * pow(H, 9));
    const static float POLY6_GRAD_PRESS = -45.f / (PI * pow(H, 6));
    const static float POLY6_GRAD_VISC = 45.f / (PI * pow(H,6));

    // PARTICLES
    // number of particles
    const static int N = 400;
}


class SPHSimulation : public Geometry {
    std::vector<Particle *> particles;
    vec3 externalForces;

    void compute_density_and_pressure();

    void compute_forces();

    void integrate();

public:
    SPHSimulation();

    ~SPHSimulation();

    // step the system by t time
    void update(float t);

    void Draw() override;

    vec3 getExternalForces() const;

    void resetExternalForces();

    void addForce(vec3 force);
};


#endif //BRAVE2_SPHSIMULATION_H