#include <GL/freeglut.h>
#include <GL/gl.h>


void renderFunction()
{
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glClear(GL_COLOR_BUFFER_BIT); glColor3f(1.0, 1.0, 1.0); glOrtho(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0); glBegin(GL_POLYGON); glVertex2f(-0.5, -0.5); glVertex2f(-0.5, 0.5); glVertex2f(0.5, 0.5); glVertex2f(0.5, -0.5); glEnd(); glFlush();

}
int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE); glutInitWindowSize(500,500); glutInitWindowPosition(100,100);
    glutCreateWindow("OpenGL - First window demo"); glutDisplayFunc(renderFunction);
    glutMainLoop(); return 0;
}