FPS with Pyglet half of monitor refresh rate

Question

I'm new to working with Pyglet and I've written a small program which moves a ball around the screen. Right now I'm having difficulty establishing a steady frame rate of 60 fps. While Pyglet is supposed to sync with my monitor's refresh rate of 60Hz, Pyglet is setting my fps to half of my refresh rate (ex. when 60Hz, 30 fps). Is there something wrong in my code that is causing this?

import pyglet
import physicalobject
import random
from pyglet.window import mouse

pyglet.resource.path = ['./resources']
pyglet.resource.reindex()

ball_image = pyglet.resource.image("ball2.png")

#sets clock format
fps_display = pyglet.clock.ClockDisplay(format='%(fps).2f fps')

def center_image(image):
    image.anchor_x = image.width/2
    image.anchor_y = image.height/2

center_image(ball_image)
ball = physicalobject.PhysicalObject(img=ball_image, x = 400, y = 300)
ball.scale = .2
ball.velocity_x = random.randint(-4,4)*150
ball.velocity_y = random.randint(-4,4)*150

#Calls update function to set new ball position based on velocity
def update(dt):
     ball.update(dt)

@window.event
def on_mouse_drag(x, y, dx, dy, button, modifiers):
     ball.x = x
     ball.y = y
     ball.velocity_x = dx * 20
     ball.velocity_y = dy * 20

@window.event
def on_draw():
     window.clear()
     ball.draw()
     fps_display.draw()

def main():
     pyglet.clock.schedule_interval(update, 1/120.0)
     pyglet.app.run()

if __name__ == '__main__':
     main()

Do you see an improvement if you use `pyglet.clock.schedule(update)` instead of `schedule_interval`? — robots.jpg, May 14 '12 at 19:07
At the time of the question, what version of Pyglet were you running because 1.1.1 had some issues regarding framerate. — Torxed, Feb 06 '13 at 17:57

score 1 · Answer 1 · answered Aug 30 '12 at 14:38

1

Pyglet simply doesn't handle it correctly on some systems, you have to disable your application window's vsync in order to get it to work. Here's an example script you can run to get a feel for how it works:

import pyglet

# Show FPS
fps = pyglet.clock.ClockDisplay()

# The game window
class Window(pyglet.window.Window):
    def __init__(self):
        super(Window, self).__init__(vsync = False)
        # Run "self.update" 128 frames a second and set FPS limit to 128.
        pyglet.clock.schedule_interval(self.update, 1.0/128.0)
        pyglet.clock.set_fps_limit(128)

    # You need the dt argument there to prevent errors,
    # it does nothing as far as I know.
    def update(self, dt): 
        pass

    def on_draw(self):
        pyglet.clock.tick() # Make sure you tick the clock!
        self.clear()
        fps.draw()

# Create a window and run
win = Window()
pyglet.app.run()

answered Aug 30 '12 at 14:38

Vine

61
3

This works, almost.. except that you can't use a clock.. It has limitations. – Torxed Feb 06 '13 at 18:03
So the vsync part is true, if you set `vsync = True` then the application will be forced to lock to the monitor refreshrate, this is to reduce screen tearing that might occur if the application refreshes in a such a synced way that the eye can catch the differences.. meaning that it will appear out of sync or laggy when in fact it's just your screen rendering so fast and at such interval that the updates occur when the monitor refreshes, ergo screen-tearing. But the clock will not show a proper refreshrate, it will just give you a illusion of a refreshrate display :) – Torxed Feb 06 '13 at 18:14
@Torxed What limitations? I was under the impression the clock _should_ be used for scheduling events. – Henry Gomersall Apr 28 '14 at 13:00

score 1 · Answer 2 · answered Feb 06 '13 at 18:06

import pyglet
from time import time, sleep

class Window(pyglet.window.Window):
    def __init__(self, refreshrate):
        super(Window, self).__init__(vsync = False)
        self.frames = 0
        self.framerate = pyglet.text.Label(text='Unknown', font_name='Verdana', font_size=8, x=10, y=10, color=(255,255,255,255))
        self.last = time()
        self.alive = 1
        self.refreshrate = refreshrate

    def on_draw(self):
        self.render()

    def render(self):
        self.clear()
        if time() - self.last >= 1:
            self.framerate.text = str(self.frames)
            self.frames = 0
            self.last = time()
        else:
            self.frames += 1
        self.framerate.draw()
        self.flip()

    def on_close(self):
        self.alive = 0

    def run(self):
        while self.alive:
            self.render()
            event = self.dispatch_events()
            sleep(1.0/self.refreshrate)

win = Window(23) # set the fps
win.run()

Note the lack of the clock feature. Also, try setting vsync = True and removing the sleep(1.0/self.refreshrate), this will lock the refresh rate to your monitor.

Also, note that i don't use pyglet.app.run() to lock the rendering process, i call self.dispatch_events() instead.. it doesn't really do anything except let the graphic "poll" and move on, without it.. pyglet waits for a poll to occur, which pyglet.app.run() normally does.

FPS with Pyglet half of monitor refresh rate

2 Answers2

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