I am a beginner in OpenGL and tried to write my first program to draw some points and a line. I can see that the window opens with white background but no line is drawn. I was expecting to see red colored (because glColor3f(1.0, 0.0, 0.0);) dots (pixels) and line. But nothing is seen. Here is my code. 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 display() { glClear(GL_COLOR_BUFFER_BIT); glColor3f(1.0, 0.0, 0.0); glBegin(GL_POINTS); for(int i = 0; i < 10; i++) { glVertex2i(10+5*i, 110); } glEnd(); //draw a line glBegin(GL_LINES); glVertex2i(10,10); glVertex2i(100,100); glEnd(); glFlush(); } int main(int argc, char** argv) { //Initialize Glut glutInit(&argc, argv); //setup some memory buffers for our display glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB); //set the window size glutInitWindowSize(500, 500); //create the window with the title 'points and lines' glutCreateWindow("Points and Lines"); init2D(0.0, 0.0, 0.0); glutDisplayFunc(display); glutMainLoop(); } I wanted to verify that the glcontext was opening properly and used this code: int main(int argc, char **argv) { glutInit(&argc, argv); //setup some memory buffers for our display glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB); //set the window size glutInitWindowSize(500, 500); //create the window with the title 'points and lines' glutCreateWindow("Points and Lines"); char *GL_version=(char *)glGetString(GL_VERSION); puts(GL_version); char *GL_vendor=(char *)glGetString(GL_VENDOR); puts(GL_vendor); char *GL_renderer=(char *)glGetString(GL_RENDERER); puts(GL_renderer); getchar(); return 0; } And the ouput I got was: 3.1.0 - Build 8.15.10.2345 Intel Intel(R) HD Graphics Family Can someone point out what I am doing wrong ? Thanks.