/*==========================================
Title:  Torus
Author: Filip Bojovic
Date:   20.12.2020.
==========================================*/

#include <GL/freeglut.h>
#include <math.h>
#include <vector>
#include <glm/vec3.hpp>
#include <glm/gtx/rotate_vector.hpp>
#include <stdio.h>

#define NUM_OF_CIRCLES 100
#define CIRCLE_DOTS 15
#define INNER_TORUS_R 1
#define OUTER_TORUS_R 1.25
#define FPS 60

using namespace std;
using namespace glm;

vec3 camera = vec3(2.0, 2.0, 2.0);
vector<vector<vec3>> torus;

void drawPolygon(vector<vec3> points)
{
    glColor3f(1.0, 1.0, 1.0);
    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    glBegin(GL_POLYGON);
        for(int i = 0; i < points.size(); i++)
            glVertex3f(points[i].x, points[i].y, points[i].z);
    glEnd();
}

void createTorus()
{
    double alpha = 2 * M_PI / NUM_OF_CIRCLES;
    torus.resize(2);

    torus[0].resize(NUM_OF_CIRCLES);
    torus[1].resize(NUM_OF_CIRCLES);

    torus[0][0] = vec3(INNER_TORUS_R + ((OUTER_TORUS_R - INNER_TORUS_R) / 2.0f), 0.0, 0.0);
    torus[1][0] = vec3((OUTER_TORUS_R - INNER_TORUS_R) / 2.0f, 0.0, 0.0);

    for(int i = 1; i < NUM_OF_CIRCLES; i++)
    {
        torus[0][i] = rotateY(vec<3, double, defaultp>(torus[0][i - 1]), alpha);
        torus[1][i] = rotateY(vec<3, double, defaultp>(torus[1][i - 1]), alpha);
    }
}

void drawTorus()
{
    double alpha = 2 * M_PI / CIRCLE_DOTS;
    double diff = (OUTER_TORUS_R - INNER_TORUS_R) / 2.0f;

    vec3 rotateVec; //vektor oko kog se rotira
    vector<vec3> poly;

    poly.resize(CIRCLE_DOTS);

    for(int i = 0; i < torus[0].size(); i++)
    {
        poly[0] = torus[1][i];
        rotateVec = rotateY(vec<3, double, defaultp> (poly[0]), M_PI_2);

        for(int j = 1; j < poly.size(); j++)
            poly[j] = rotate(vec<3, double, defaultp> (poly[j - 1]), alpha, vec<3, double, defaultp> (rotateVec));
        for(int j = 0; j < poly.size(); j++)
            poly[j] += torus[0][i];
        drawPolygon(poly);
    }
}

void drawAxis()
{
    glColor3f(1.0, 0.0, 0.0);
    glBegin(GL_LINES);
        glVertex3f(0.0, 0.0, 0.0);
        glVertex3f(1.0, 0.0, 0.0);
    glEnd();

    glColor3f(0.0, 1.0, 0.0);
    glBegin(GL_LINES);
        glVertex3f(0.0, 0.0, 0.0);
        glVertex3f(0.0, 1.0, 0.0);
    glEnd();

    glColor3f(0.0, 0.0, 1.0);
    glBegin(GL_LINES);
        glVertex3f(0.0, 0.0, 0.0);
        glVertex3f(0.0, 0.0, 1.0);
    glEnd();
}

void display()
{
    glClear(GL_COLOR_BUFFER_BIT);

    drawTorus();

    drawAxis();
    glFlush();
}

void initGL()
{
    glClearColor(0.0, 0.0, 0.0, 1.0);
}

void timer(int v)
{
    camera = rotateY(vec<3, double, defaultp> (camera), 1 * M_PI / 180.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    gluLookAt(camera.x, camera.y, camera.z, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

    glutTimerFunc(1000 / FPS, timer, v);
    glutPostRedisplay();
}

void reshape(GLsizei width, GLsizei height)
{
    if(!height)
        height = 1;
    GLfloat aspect = (GLfloat)width / (GLfloat)height;

    glViewport(0, 0, width, height);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(80.0f, aspect, 0.1f, 50.0f);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    gluLookAt(camera.x, camera.y, camera.z, 0.0 ,0.0, 0.0, 0.0, 1.0, 0.0);
}

int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(500, 500);
    glutInitWindowPosition(200, 200);
    glutCreateWindow("Torus");

    createTorus();

    glMatrixMode(GL_MODELVIEW); //primenjuje dodatne operacija matrica na stek modela
    glLoadIdentity(); //postavlja matricu modelView na jedinicnu. U sustini je restartuje na pocetno stanje.
    gluLookAt(camera.x, camera.y, camera.z, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

    glutDisplayFunc(display);
    glutTimerFunc(100, timer, 0);
    glutReshapeFunc(reshape); //callBack fja kada se promeni velicina prozora
    initGL();
    glutMainLoop();
}