Something

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

void render() {
  glClear(GL_COLOR_BUFFER_BIT);
  glBegin(GL_POINTS);
  glVertex2i(150,150);
  glEnd();
  glFlush();
}

int main(int argc, char **argv) {
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
  glutInitWindowSize(400, 300);
  glutInitWindowPosition(100, 100);
  glutCreateWindow("OpenGL Test");
  glClearColor(0.0, 0.0, 0.0, 0.0);
  glViewport(0, 0, 400, 300);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glOrtho(0.0, 400.0, 0.0, 300.0, -1.0, 1.0);
  glutDisplayFunc(&render);
  glutMainLoop();
  return 0;
}