ERROR
=====

libsupertux2.a(fireworks.cpp.o): In function `void __gnu_cxx::new_allocator<PhysicsParticles>::construct<PhysicsParticles, Vector&, int, int, int, int, int, Color, int, float, int, float, float, float, float, float, bool>(PhysicsParticles*, Vector&, int&&, int&&, int&&, int&&, int&&, Color&&, int&&, float&&, int&&, float&&, float&&, float&&, float&&, float&&, bool&&)':
fireworks.cpp:(.text._ZN9__gnu_cxx13new_allocatorI16PhysicsParticlesE9constructIS1_JR6Vectoriiiii5ColorififffffbEEEvPT_DpOT0_[_ZN9__gnu_cxx13new_allocatorI16PhysicsParticlesE9constructIS1_JR6Vectoriiiii5ColorififffffbEEEvPT_DpOT0_]+0x301): undefined reference to `PhysicsParticles::PhysicsParticles(Vector const&, int, int, float, float, int, Color, int, float, int, float, float, float, float, float, bool)'
collect2: error: ld returned 1 exit status
CMakeFiles/supertux2.dir/build.make:112: recipe for target 'supertux2' failed
make[2]: *** [supertux2] Error 1
CMakeFiles/Makefile2:68: recipe for target 'CMakeFiles/supertux2.dir/all' failed
make[1]: *** [CMakeFiles/supertux2.dir/all] Error 2
Makefile:151: recipe for target 'all' failed
make: *** [all] Error 2

=====================
physics_particles.hpp
=====================
#ifndef HEADER_SUPERTUX_OBJECT_PHYSICS_PARTICLES_HPP
#define HEADER_SUPERTUX_OBJECT_PHYSICS_PARTICLES_HPP

#include "object/particles.hpp"

class PhysicsParticles : public Particles
{
	private:
		struct Particle
		{
			Vector pos, vel;

			Particle() :
				pos(),
				vel()
			{

			}
		};

		float m_gravity = -9.8f; // adjust as needed

	public:
		PhysicsParticles(const Vector& epicenter, int min_angle, int max_angle,
					const float min_initial_velocity, const float max_initial_velocity,
					int number, Color color,
					int size, float life_time, int drawing_layer,
					float a, float b, float c, float sin_coeff, float cos_coeff,
					bool use_gravity);
		virtual bool is_saveable() const {
			return false;
		}

		virtual void update(float elapsed_time);
		virtual void draw(DrawingContext& context);

		Color m_color;
		Timer m_timer;
		bool m_live_forever;
		float m_size;
		int m_drawing_layer;
		std::vector<std::unique_ptr<Particle>> m_particles;

		float m_a;
		float m_b;
		float m_c;
		float m_sin_coeff;
		float m_cos_coeff;
		bool m_use_gravity;
};

#endif

/* EOF */

==============
physics_particles.cpp
=====================
#include "object/physics_particles.hpp"

#include <math.h>

#include "math/random_generator.hpp"
#include "math/util.hpp"
#include "object/camera.hpp"
#include "supertux/sector.hpp"
#include "video/drawing_context.hpp"
#include "video/video_system.hpp"
#include "video/viewport.hpp"


PhysicsParticles::PhysicsParticles(const Vector& epicenter, int min_angle, int max_angle,
					const float min_initial_velocity, const float max_initial_velocity,
					int number, Color color,
					int size, float life_time, int drawing_layer,
					float a, float b, float c, float sin_coeff, float cos_coeff,
					bool use_gravity);
	m_timer(),
	m_live_forever(),
	m_color(color_),
	m_size(static_cast<float>(size_)),
	m_drawing_layer(drawing_layer),
	m_a(a),
	m_b(b),
	m_c(c),
	m_sin_coeff(sin_coeff),
	m_cos_coeff(cos_coeff),
	m_use_gravity(use_gravity),
	particles()
{
	if(life_time == 0)
	{
		m_live_forever = true;
	}

	else
	{
		m_live_forever = false;
		timer.start(life_time);
	}

	// create particles
	for(int i = 0; i < number; i++)
	{
		Particle particle = std::unique_ptr<Particle>(new Particle);
		particle->pos = epicenter;

		float velocity = (min_initial_velocity == max_initial_velocity) ? min_initial_velocity :
                    graphicsRandom.randf(min_initial_velocity, max_initial_velocity);
		float angle = (min_angle == max_angle) ? static_cast<float>(min_angle) * (math::PI / 180.0f) :
			graphicsRandom.randf(static_cast<float>(min_angle), static_cast<float>(max_angle)) * (math::PI / 180.0f);  // convert to radians

		// vel.x = a * x^3 + b * x^2 + cx + m_sin_coeff(sin(x)) + m_cos_coeff(cos(x))
		particle->vel.x = (sinf(angle)) * velocity;
		particle->vel.y = (-cosf(angle)) * velocity;
		particles.push_back(std::move(particle));
	}
}

void
ParticlesParticles::update(float dt)
{
	// first pass will update particle velocities
	for(int i = 0; i < m_particles.size(); i++)
	{
		m_particles[i]->vel.x += m_a * powf(dt, 3.0f) + m_b * powf(dt, 2.0f) + m_c * dt +
			m_sin_coeff * sin(particle->pos.x) + m_cos_coeff * cos(particle->pos.x);
		m_particles[i]->vel.y += m_a * powf(dt, 3.0f) + m_b * powf(dt, 2.0f) + m_c * dt +
			m_sin_coeff * sin(particle->pos.y) + m_cos_coeff * cos(particle->pos.y);
		if(m_use_gravity)
		{
			m_particles[i]->vel.y += m_gravity * powf(dt, 2.0f);
		}

	}

	// now we can update positions based on velocity
	for(int i = 0; i < m_particles.size(); i++)
	{
		m_particles[i]->pos.x += m_particles[i]->vel.x * dt;
		m_particles[i]->pos.y += m_particles[i]->vel.y * dt;

		if(m_particles[i]->pos.x < camera.x || m_particles[i]->pos.x > static_cast<float>(SCREEN_WIDTH) + camera.x ||
			m_particles[i]->pos.y < camera.y || m_particles[i]->pos.y > static_cast<float>(SCREEN_HEIGHT) + camera.y)
		{
			m_particles.erase(i);
		}
	}


/*
  Vector camera = Sector::current()->camera->get_translation();




  // update particles
  for(auto i = particles.begin(); i != particles.end(); ) {
    (*i)->pos.x += (*i)->vel.x * dt;
    (*i)->pos.y += (*i)->vel.y * dt;

    (*i)->vel.x += accel.x * dt;
    (*i)->vel.y += accel.y * dt;

    if((*i)->pos.x < camera.x || (*i)->pos.x > static_cast<float>(SCREEN_WIDTH) + camera.x ||
       (*i)->pos.y < camera.y || (*i)->pos.y > static_cast<float>(SCREEN_HEIGHT) + camera.y) {
      i = particles.erase(i);
    } else {
      ++i;
    }
  }

  if((timer.check() && !live_forever) || particles.size() == 0)
    remove_me(); */
}

===========================
fireworks.cpp modifications
===========================
    /*sector->add_object(std::make_shared<Particles>(pos, 0, 360, 140, 140,
                                                   Vector(0, 0), 45, Color(red, green, 0), 3, 1.3f,
                                                   LAYER_FOREGROUND1+1));*/
    sector->add_object(std::make_shared<PhysicsParticles>(pos, 0, 360, 140, 140,
                                                          45, Color(red, green, 0), 3, 1.3f,
                                                          LAYER_FOREGROUND1+1,
                                                          .01f, .02f, .03f, 0.0f, 0.0f, true));
===========================
ERROR (repeated from above)
===========================

libsupertux2.a(fireworks.cpp.o): In function `void __gnu_cxx::new_allocator<PhysicsParticles>::construct<PhysicsParticles, Vector&, int, int, int, int, int, Color, int, float, int, float, float, float, float, float, bool>(PhysicsParticles*, Vector&, int&&, int&&, int&&, int&&, int&&, Color&&, int&&, float&&, int&&, float&&, float&&, float&&, float&&, float&&, bool&&)':
fireworks.cpp:(.text._ZN9__gnu_cxx13new_allocatorI16PhysicsParticlesE9constructIS1_JR6Vectoriiiii5ColorififffffbEEEvPT_DpOT0_[_ZN9__gnu_cxx13new_allocatorI16PhysicsParticlesE9constructIS1_JR6Vectoriiiii5ColorififffffbEEEvPT_DpOT0_]+0x301): undefined reference to `PhysicsParticles::PhysicsParticles(Vector const&, int, int, float, float, int, Color, int, float, int, float, float, float, float, float, bool)'
collect2: error: ld returned 1 exit status
CMakeFiles/supertux2.dir/build.make:112: recipe for target 'supertux2' failed
make[2]: *** [supertux2] Error 1
CMakeFiles/Makefile2:68: recipe for target 'CMakeFiles/supertux2.dir/all' failed
make[1]: *** [CMakeFiles/supertux2.dir/all] Error 2
Makefile:151: recipe for target 'all' failed
make: *** [all] Error 2
-----------------------------------