#CCG FINAL PART3 (pendulum)

//pendulum.h
#pragma once
class pendulum
{
public:
    coord carrier;
    coord init_ticker;
    coord curr_ticker;

    float rope_len;
    float curr_angle, angle_degree, start_angle;
    float amplitude, start_amplitude;
    int mass;

    void set(coord carrier, coord ticker);
    void set_physics(bool k);

    void count_rope_len();
    void count_angle();

    void draw();
    void move(float t);

    bool get_physics();

    pendulum();
    ~pendulum();

private:
    bool physics;
    int ticker_rad, ticker_border;
};





//pendulum.cpp
#include "stdafx.h"

using namespace std;

pendulum::pendulum() {
    physics = false;
}

pendulum::~pendulum()
{
}

void pendulum::set_physics(bool ka) {
    this->physics = ka;
}

bool pendulum::get_physics() {
    return this->physics;
}

void pendulum::set(coord carrier, coord ticker) {

    this->carrier = carrier;

    this->init_ticker = ticker;
    this->curr_ticker = ticker;

    this->start_angle = 0;

    this->count_angle();

    this->amplitude = this->curr_angle;
    this->start_amplitude = this->amplitude;

    this->physics = false;

    this->ticker_rad = 40;
    this->ticker_border = 5;
}

void pendulum::count_angle() {

    this->count_rope_len();

    float TM = abs(this->carrier.x - this->curr_ticker.x);
    float CT = this->rope_len;

    float angle = asin(TM / CT);

    this->curr_angle = angle;
    this->angle_degree = angle * 180 / M_PI;
}

void pendulum::count_rope_len() {
    coord carr = this->carrier;
    coord tick = this->curr_ticker;

    float CM = abs(carr.y - tick.y);
    float TM = abs(carr.x - tick.x);
    float CT = sqrt(TM*TM + CM*CM);

    this->rope_len = CT;
}

void draw_pendulum_bracket(int x, int y, int size) {

    glLineWidth(3.0);
    glColor3f(0, 0, 0);

    glBegin(GL_LINES);
    glVertex2f(x, y);
    glVertex2f(x, y - size);
    glEnd();

    //outer
    GLfloat phi = 0, theta = 0;
    glBegin(GL_POLYGON);
    glColor3f(0, 0, 0);
    for (phi = 0; phi < 2 * M_PI; phi += 0.1) {
        glVertex2f(x + 8 * cos(phi), (y - size) + 8 * sin(phi));
    }
    glEnd();

    //inner
    glBegin(GL_POLYGON);
    glColor3f(0.6, 0.6, 0.6);
    for (phi = 0; phi < 2 * M_PI; phi += 0.1) {
        glVertex2f(x + 5 * cos(phi), (y - size) + 5 * sin(phi));
    }
    glEnd();

}

void pendulum::draw() {

    coord carrier = this->carrier;
    coord ticker = this->curr_ticker;


    //carrier
    draw_pendulum_bracket(carrier.x, carrier.y + 20, 15);

    //ticker outer
    GLfloat phi = 0, theta = 0;
    glBegin(GL_POLYGON);
    glColor3f(0, 0, 0);
    for (phi = 0; phi < 2 * M_PI; phi += 0.1) {
        glVertex2f(ticker.x + this->ticker_rad * cos(phi), ticker.y + this->ticker_rad * sin(phi));
    }
    glEnd();

    //ticker inner
    glBegin(GL_POLYGON);
    glColor3f(1, 1, 1);
    for (phi = 0; phi < 2 * M_PI; phi += 0.1) {
        glVertex2f(ticker.x + (this->ticker_rad - this->ticker_border) * cos(phi), ticker.y + (this->ticker_rad - this->ticker_border) * sin(phi));
    }
    glEnd();

    //ticker center
    glPointSize(7.0);
    glColor3f(0, 0, 0);
    glBegin(GL_POINTS);
        glVertex2f(ticker.x, ticker.y);
    glEnd();

    //rope
    glLineWidth(3.0);
    glColor3f(0, 0, 0);
    glBegin(GL_LINES);
        glVertex2f(carrier.x, carrier.y);
        glVertex2f(ticker.x, ticker.y);
    glEnd();
}

void pendulum::move(float t) {

    coord carr = this->carrier;
    coord tick = this->curr_ticker;

    if (tick.y - this->ticker_rad > FLOOR_HEIGHT && tick.y + this->ticker_rad < ROOF_HEIGHT) {
        this->count_angle();

        float omega = sqrt(G_CONST / this->rope_len);
        //float attenuation = pow(M_E, -log(this->amplitude / (this->amplitude * 0.5)));
        float attenuation_k = 0.99999;
        float phi = this->amplitude * cos(omega * t + this->start_angle);
        this->amplitude *= attenuation_k;

        this->curr_angle = phi;

        float TM = this->rope_len * sin(phi);
        float CM = this->rope_len * sin(90*M_PI/180 - phi); //1,57 rad

        coord T;
        T.x = carr.x - TM;
        T.y = carr.y - CM;

        this->curr_ticker = T;
    }
}