pyglet doesn't draw on first iteration

[anatoly techtonik]

Why pyglet doesn't display label on the first iteration?

On my Vista machine it is visible only after I hit Enter the second time.

import pyglet

wincfg = pyglet.gl.Config(double_buffer=False)

window = pyglet.window.Window(config=wincfg)

label = pyglet.text.Label('[]',

                          font_name='Lucida Console',

                          font_size=14,

                          x=10, y=10)

label.draw()

pyglet.gl.glFlush()

window.dispatch_events()

raw_input("Done.")

label.draw()

pyglet.gl.glFlush()

window.dispatch_events()

raw_input("Done.")

[Anonymouse]

I can't be sure, but I think it's because you need to dispatch_events() once before drawing anything so that an on_resize event gets handled, which will set the projection matrix for the window. If you draw before it, the projection matrix is probably such that you can't see wherever the text gets drawn. So call window.dispatch_events() once before drawing and it does display.

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[anatoly techtonik]

Doesn't help. Here is the script with added event logger for the window. On my machine the output is:

>py testdraw.py

on_activate()

on_show()

on_resize(width=640, height=480)

on_expose()

Before Label draw.

on_deactivate()

After.

Done.

import pyglet

wincfg = pyglet.gl.Config(double_buffer=False)

window = pyglet.window.Window(config=wincfg)

window.push_handlers(pyglet.window.event.WindowEventLogger())

window.dispatch_events()

raw_input("Before Label draw.")

label = pyglet.text.Label('[]',

                          font_name='Lucida Console',

                          font_size=14,

                          x=10, y=10)

label.draw()

pyglet.gl.glFlush()

window.dispatch_events()

raw_input("After.")

label.draw()

pyglet.gl.glFlush()

window.dispatch_events()

raw_input("Done.")

[Anonymouse]

You mean it doesn't draw after you press enter for the first time? Because it does for me.

[anatoly techtonik]

Exactly. It draws only after "After." is displayed and I press Enter.

Are you on a Windows Vista too?

[Anonymouse]

I'm on linux (ubuntu 12.10). Maybe try adding a window.flip() after label.draw()?

[anatoly techtonik]

I'm afraid that without window.flip() may break pyglet on other platforms with pyglet.gl.Config(double_buffer=False). Does it work the same way for Linux? I think that for the proper test another label should be drawn after the "After." string is printed.

[anatoly techtonik]

Updated test with .flip()  Still fails on Windows to draw after the first draw/flush/dispatch. Still work ok on Linux no matter if flip() is used or not. pyglet failed under Wine so no way to test without Windows system I am afraid.