#include <GLUT/GLUT.h>
#include <math.h>
#include <stdio.h>
#include <iostream>


void display();
using namespace std;
float xmin=-100;
float ymin=-100;
float xmax=50;
float ymax=50;
float xd1,yd1,xd2,yd2;

void init(void)
{
    glClearColor(0.0,0,0,0);
    glMatrixMode(GL_PROJECTION);
    gluOrtho2D(-300,300,-300,300);
}

int code(float x,float y)
{
    int c=0;
    if(y>ymax)c=8;
    if(y<ymin)c=4;
    if(x>xmax)c=c|2;
    if(x<xmin)c=c|1;
    return c;
}

void cohen_Line(float x1,float y1,float x2,float y2)
{
    int c1=code(x1,y1);
    int c2=code(x2,y2);
    float m=(y2-y1)/(x2-x1);
    while((c1|c2)>0)
    {
        if((c1 & c2)>0)
        {
            exit(0);
        }

        float xi=x1;float yi=y1;
        int c=c1;
        if(c==0)
        {
            c=c2;
            xi=x2;
            yi=y2;
        }
        float x = 0.0,y = 0.0;
        if((c & 8)>0)
        {
            y=ymax;
            x=xi+ 1.0/m*(ymax-yi);
        }
        else
            if((c & 4)>0)
            {
                y=ymin;
                x=xi+1.0/m*(ymin-yi);
            }
            else
                if((c & 2)>0)
                {
                    x=xmax;
                    y=yi+m*(xmax-xi);
                }
                else
                    if((c & 1)>0)
                    {
                        x=xmin;
                        y=yi+m*(xmin-xi);
                    }

        if(c==c1)
        {
            xd1=x;
            yd1=y;
            c1=code(xd1,yd1);
        }

        if(c==c2)
        {
            xd2=x;
            yd2=y;
            c2=code(xd2,yd2);
        }
    }

    display();

}
int i = 0;
void useMouse(int button, int state, int x, int y)
{
    if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN){
        //cout << "here " << x  << " "<< 600 - y << endl;
        if (i == 1){
            xd2 = x - 300;
            yd2 = (600 - y) - 300;

            cout << xd2 << " " << yd2 << endl;
            i++;
        }
        if (i == 0){
            xd1 = x - 300;
            yd1 = (600 - y) - 300;
            cout << xd1 << " " << yd1 << endl;
            i++;
        }

    }
}
void useKey(unsigned char key,int x,int y)
{
    if(key=='q')
    {  cout<<"good! ";
        cohen_Line(xd1,yd1,xd2,yd2);
        glFlush();
    }
}
void display()
{

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    glClear(GL_COLOR_BUFFER_BIT);

    glColor3f(0.0,1.0,1.0);

    glBegin(GL_LINE_LOOP);
    glVertex2i(xmin,ymin);
    glVertex2i(xmin,ymax);
    glVertex2i(xmax,ymax);
    glVertex2i(xmax,ymin);
    glEnd();
    glColor3f(1.0,1.0,0.0);
    if (i == 2){
        glBegin(GL_LINES);
        glVertex2i(xd1,yd1);
        glVertex2i(xd2,yd2);
        glEnd();
        glFlush();
    }
    glFlush();


}


int main(int argc,char** argv)
{


    glutInit(&argc,argv);
    glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
    glutInitWindowSize(600,600);
    glutInitWindowPosition(0,0);
    glutCreateWindow("~");
    glutDisplayFunc(display);
    glutKeyboardFunc(useKey);
    glutMouseFunc(useMouse);
    init();
    glutMainLoop();

    return 0;
}
//сделать чтобы несколько прямых рисовалось ,