OpenGL - drawing triangles

from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *


def init():
    glClearColor(1, 1, 1, 1)
    gluOrtho2D(-1, 1, -1, 1)


def triangle():
    glClear(GL_COLOR_BUFFER_BIT)
    glColor3f(1, 0, 0)
    glBegin(GL_TRIANGLES)

    glColor3f(1, 0, 0)
    glVertex2f(-1, -1)

    glColor3f(0, 1, 0)
    glVertex2f(1, -1)

    glColor3f(0, 0, 1)
    glVertex2f(0, 1)

    glEnd()
    glFlush()


def main():
    glutInit(sys.argv)
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB)
    glutInitWindowSize(800, 600)
    glutInitWindowPosition(50, 50)
    glutCreateWindow("Triangle")
    glutDisplayFunc(triangle)
    init()
    glutMainLoop()


if __name__ == '__main__':
    main()