Shaheed Minar

#include <GL/glut.h>
#include<math.h>


void init2D(float r, float g, float b)
{
        glClearColor(r,g,b,0.0);
        glMatrixMode (GL_PROJECTION);
        gluOrtho2D (0.0, 200.0, 0.0, 150.0);
}
void DrawCircle(float cx, float cy, float r, int num_segments)
{

    float theta = 2 * 3.1415926 / float(num_segments);
    float tangetial_factor = tanf(theta);//calculate the tangential factor

    float radial_factor = cosf(theta);//calculate the radial factor

    float x = r;//we start at angle = 0

    float y = 0;

    glBegin(GL_POLYGON);
    glColor3f(50.0f,0.0f,0.f);
    for(int ii = 0; ii < num_segments; ii++)
    {
        glVertex2f(x + cx, y + cy);//output vertex
        float tx = -y;
        float ty = x;

        x += tx * tangetial_factor;
        y += ty * tangetial_factor;

        x *= radial_factor;
        y *= radial_factor;
    }
    glEnd();
}


void display(void)
{
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

        DrawCircle(100.0f, 50.0f, 26.0f, 50.0f);
    glColor3f(1.0,1.0,1.0);
    glLineWidth(5);

        glBegin(GL_POLYGON);
        glVertex2i(5,10);
        glVertex2i(165,10);
        glVertex2i(180,20);
        glVertex2i(20,20);
    glEnd();

    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);


        glBegin(GL_POLYGON);
        glVertex2i(22,20);
        glVertex2i(40,20);
        glVertex2i(40,50);
        glVertex2i(22,50);
    glEnd();

        glBegin(GL_POLYGON);
        glVertex2i(50,20);
        glVertex2i(70,20);
        glVertex2i(70,60);
        glVertex2i(50,60);
    glEnd();

        glBegin(GL_POLYGON);
        glVertex2i(80,20);
        glVertex2i(120,20);
        glVertex2i(120,90);
        glVertex2i(80,90);
    glEnd();

        glBegin(GL_POLYGON);
        glVertex2i(130,20);
        glVertex2i(150,20);
        glVertex2i(150,60);
        glVertex2i(130,60);
    glEnd();

        glBegin(GL_POLYGON);
        glVertex2i(160,20);
        glVertex2i(179,20);
        glVertex2i(179,50);
        glVertex2i(160,50);
    glEnd();

        glBegin(GL_POLYGON);
        glVertex2i(80,90);
        glVertex2i(120,90);
        glVertex2i(130,100);
        glVertex2i(90,100);
    glEnd();

    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);

    glFlush();
}
//////////////////////////////////////////////////////////////////////////////////////
void main(int argc,char *argv[])
{
        glutInit(&argc,argv);
        glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
        glutInitWindowSize (500, 500);
        glutInitWindowPosition (100, 100);
        glutCreateWindow ("points and lines");
        init2D(0.0,0.0,0.0);
        glutDisplayFunc(display);
        glutMainLoop();
}