PyGame Lag when blitting background

2
votes

I am trying to reduce the lag in my game as it is unbearable. I understand that when blitting large images I should expect some lag, but I don't see any ways to reduce it. I have the code here: https://gist.github.com/Mrmeguyme/ce1a844af21695d1b853ef88fe8de5aa

The background is 1280x720px, the ground is 1280x100px, and my character is 50x50px.

2
pythonpygame

2 Answers

5
votes

See http://www.pygame.org/docs/ref/surface.html#pygame.Surface.convert_alpha

This is what I do for all my programs:

def loadify(img):
    return pygame.image.load(img).convert_alpha()

I just replace pygame.image.load with loadify to save typing. This converts the image to the proper pixel format for faster and easier blitting.

2
votes

Your images likely have per-pixel transparency. Convert them to opaque.

faster_surface = surface_loaded_directly_from_png.convert()

Of course this isn't applicable to the character, but for the background it will improve things a bit.

EDIT: I also notice you're not calling clock.tick() anywhere. That should smooth things out and removed perceived slowdowns that are actually just the CPU naturally speeding up and slowing down.