Introduction - If you have any usage issues, please Google them yourself
OpenGL simple examples.
glLoadIdentity()
glClear(GL_COLOR_BUFFER_BIT)
glBegin(GL_POLYGON)
glColor4f(1.0f, 0.0f, 0.0f, 1.0f)
glVertex2f(100.0f, 50.0f)
glColor4f(0.0f, 1.0f, 0.0f, 1.0f)
glVertex2f(450.0f, 400.0f)
glColor4f(0.0f, 0.0f, 1.0f, 1.0f)
glVertex2f(450.0f, 50.0f)
glVertex2f(100.0f, 400.0f)
glEnd()
glFlush()