from OpenGL import *
from OpenGL.GL import *
import glfw

width = 320 * 5
height = 200 * 5

def draw_object():
    # draw a line strip
    glBegin(GL_LINE_STRIP)
    if True:                                                        # to create an indent in Python
        glColor3f(0.0, 0.9, 0.0)
        glVertex2f(0.5, 0.5)
        glVertex2f(0.4, 0.4)
        glVertex2f(0.3, 0.3)
        glVertex2f(0.5, 0.4)
        glVertex2f(0.1, 0.5)
        glVertex2f(-0.3, -0.4)
        glVertex2f(0.3, 0.3)
        glVertex2f(-0.9, 0.2)
    glEnd()

def draw():
    global width
    global height
           
    # draw my object
    draw_object()

def process_input(window):
    if glfw.get_key(window, glfw.KEY_Q) == glfw.PRESS:
        glfw.set_window_should_close(window, True)

def main():
    global width
    global height

    init_status = glfw.init()
    if not init_status:
        print('Cannot initialize glfw\n')
        exit()
         
    window = glfw.create_window(width, height, 'Triagle', None, None)        # create window
    if not window:
        glfw.terminate()
        print('Cannot create window\n')
        exit()

    glfw.set_window_pos(window, 480, 100)
    glfw.make_context_current(window)                           # create opengl object and link it to window
    glfw.swap_interval(1)                                       # force swap interval

    version = glGetString(GL_VERSION)
    print(version)

    while not glfw.window_should_close(window):
        fb_size = glfw.get_framebuffer_size(window)             # get current window width and height
        width = fb_size[0]
        height = fb_size[1]
        glViewport(0, 0, width, height)                         # everytime the windows is resized - update viewport
        glClearColor(0.2, 0.2, 0.2, 1)                           # set clear color
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)      # clear screen
        
        draw()
        process_input(window)                                   # check keys

        glfw.swap_buffers(window)                               # swap buffers
        glfw.poll_events()                                      # listen for window events
    
    glfw.destroy_window(window)
    glfw.terminate()
    return 0

main()