Question

Here is my part of code to show circle on screen but unfortunate circle is not coming on screen.

glClearColor(0, 0, 0, 0);
glClear(GL_COLOR_BUFFER_BIT);
 glPushMatrix();
glLoadIdentity();
 glColor3f(0.0f,1.0f,0.0f);
glBegin(GL_LINE_LOOP);

const float DEG2RAD = 3.14159/180;

for (int i=0; i < 360; i++)
{
    float degInRad = i*DEG2RAD;
    glVertex2f(cos(degInRad)*8,sin(degInRad)*8);
}

 glEnd();
glFlush();

I am not understanding code is seems to look ok but circle is not coming on screen.

Answer 1

Your circle is too big. The default viewport is in the range [(-1 -1), (1 1)].

BTW, you don’t need 360 segments. About 30 is usually adequate, depending on how smooth you want it.