#include <iostream>
#include <list>
#include <cmath>
#include <algorithm>

#include <GL/glut.h>
#include <GL/gl.h>
#include <GL/glu.h>

using namespace std;

double scale = 1.0;
double car_x = 0, car_y = 0;
double car_vx = 0, car_vy = 0;
void render_square(double x, double y) {
    glPushMatrix();

    double dx = 0.5;
    double dy = 0.5;
    glBegin(GL_POLYGON);
    glVertex2f(x, y);
    glVertex2f(x + dx, y);
    glVertex2f(x + dx, y - dy);
    glVertex2f(x, y - dy);
    glEnd();
    glPopMatrix();
}

void draw_line(double x, double y, double x1, double y1) {
    glBegin(GL_LINES);
    glVertex2d(x, y);
    glVertex2d(x1, y1);
    glEnd();
}

void draw_home(double x,double y){
    draw_line(0+x,0+y,3+x,0+y);
    draw_line(3+x,0+y,3+x,3+y);
    draw_line(3+x,3+y,0+x,3+y);
    draw_line(0+x,3+y,0+x,0+y);
    draw_line(0+x,3+y,1.5+x,3.75+y);
    draw_line(3+x,3+y,1.5+x,3.75+y);
    draw_line(1.25+x,1.25+y,1.25+x,1.25+y);
    draw_line(1.75+x,1.25+y,1.75+x,1.75+y);
    draw_line(1.75+x,1.75+y,1.25+x,1.75+y);
    draw_line(1.25+x,1.75+y,1.25+x,1.25+y);
    draw_line(1.25+x,1.25+y,1.75+x,1.25+y);

}
void draw_car(double x,double y){
    glColor3d(1, 0, 0);
    draw_line(0+x,0+y,1+x,0+y);
    draw_line(1+x,0+y,1+x,1+y);
    draw_line(1+x,1+y,0+x,1+y);
    draw_line(0+x,1+y,0+x,0+y);

}

void Render() {
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glLoadIdentity();
        glTranslatef(0, 0, -10);
        glColor3d(1, 1, 0);
        glScalef(scale, scale, scale);


        for(double x = -25; x < 25; x+= 5.5) {
           for(double y = -25; y < 25; y+= 5.5) {

                draw_home(x,y);
            }

        }

        draw_car(car_x,car_y);

        glFlush();
}

void update(int t) {
    double dt = 0.05;
    car_x += car_vx * dt;
    car_y += car_vy * dt;
    Render();
    glutTimerFunc(50, update, 0);
}

void keyb(unsigned char key, int x, int y) {
    if(key == '+') {
        scale *= 1.5;
    }
    if(key == '-') {
        scale *= 0.5;
    }
    if(key == 'w'){
        car_vy+=0.25;
    }
    if(key == 's'){
        car_vy-=0.25;
    }
    if(key == 'a'){
        car_vx-=0.25;
    }
    if(key == 'd'){
        car_vx+=0.25;
    }
    if(key == ' '){
        car_vx*=0.45;
        car_vy*=0.45;
    }


    cout<<key<<endl;

    Render();
}

void reshape(int w, int h) {

    // предупредим деление на ноль
    // если окно сильно перетянуто будет
    if(h == 0)
        h = 1;
    float ratio = 1.0* w / h;

    // используем матрицу проекции
    glMatrixMode(GL_PROJECTION);

        // Reset матрицы
    glLoadIdentity();

    // определяем окно просмотра
    glViewport(0, 0, w, h);

    // установить корректную перспективу.
    gluPerspective(45,ratio,1,1000);

    // вернуться к модели
    glMatrixMode(GL_MODELVIEW);
}

int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(800, 600);
    glutCreateWindow("Physics Engine");
    glEnable(GL_DEPTH_TEST);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glClearColor(0.0, 0.5, 0.5, 1.0);

    glutTimerFunc(50, update, 0);
    glutReshapeFunc(reshape);
    glutDisplayFunc(Render);
    glutKeyboardFunc(keyb);
    glutMainLoop();
}