Re: [pygame] Drawing Bullets

[Charles Joseph Christie II <sonicbhoc@xxxxxxxxx>]

On Saturday 28 April 2007 12:53:38 pm DR0ID wrote:
> Charles Joseph Christie II schrieb:
> > On Saturday 28 April 2007 11:45:15 am DR0ID wrote:
> >> Charles Joseph Christie II schrieb:
> >>> On Saturday 28 April 2007 01:28:38 am Kris Schnee wrote:
> >>>> Charles Christie wrote:
> >>>>> Well, bullets just seem to be a sticking point for me...
> >>>>
> >>>> Stick with it!
> >>>>
> >>>>> 1. bullet cleanup (self.kill, etc.) which isn't important to me right
> >>>>> now, as the demo won't be running for an extended period, and when it
> >>>>> does it'll be running on a monstrous beast of a computer that can
> >>>>> probably handle the crappy coding.
> >>>>> 2. Drawing bullets (pygame.update.dirtyrects, etc) which is VERY
> >>>>> important to me right now.
> >>>>
> >>>> I don't think you need a kill function. What I did in my shooter game
> >>>> was to have the bullets stored in two lists, and then every frame:
> >>>>
> >>>> self.player_bullets = [bullet for bullet in self.player_bullets if
> >>>> bullet.ttl > 0]
> >>>> self.enemy_bullets = [bullet for bullet in self.enemy_bullets if
> >>>> bullet.ttl > 0]
> >>>>
> >>>> This filtering gets rid of the ones whose time-to-live is expired, due
> >>>> to Python's automatic garbage-collection.
> >>>>
> >>>>> So, I tried to load an image for the bullets, and that didn't work
> >>>>> either. What happened was that it couldn't load the image... probably
> >>>>> because it doesn't exist. Which it does, though.
> >>>>>
> >>>>> It's in the project directory under the folder img/Bullet.png. When I
> >>>>> put img/Bullet.png into the load_image function it says it can't load
> >>>>> the image! I tried it with front and back slashes and it didn't work.
> >>>>
> >>>> Yeah, Python doesn't automatically handle path names. Try
> >>>> os.path.join, as in:
> >>>>
> >>>> import os
> >>>> filename = os.path.join("img","Bullet.png")
> >>>> my_image = pygame.image.load(filename).convert_alpha()
> >>>>
> >>>> As I understand it, os.path.join attaches the directory terms (any
> >>>> number of them) according to whatever format is appropriate for the
> >>>> OS.
> >>>>
> >>>>> After I get the image loaded, however, I can't add the bulletlist to
> >>>>> my list of dirtyrects to update... The dirtyrect doesn't read from
> >>>>> lists! How do I get pygame.sprite.RenderUpdates to display my bullets
> >>>>> on the screen?
> >>>>
> >>>> I haven't messed with dirty rectangle functions myself, so this one is
> >>>> beyond me.
> >>>>
> >>>> Kris
> >>>
> >>> Woohoo! Thanks! I'll try this ASAP. Still need to figure out how to get
> >>> the dirtyrects thing sorted out though...
> >>
> >> Hi
> >>
> >> if you use Renderupdates then you have to do the following:
> >>
> >> make an instance of the RenderUpdateGroup
> >> add as many sprites you want to it
> >>
> >> then in each frame of you game:
> >>        renderUGroup.clear()
> >>        # update your sprites in here
> >>        dirty_rects = renderUGroup.draw(screen)
> >>        display.update(dirty_rects)
> >>
> >> It should be more or less that thing. Try to look at an example like
> >> "chimp" on the pagame website.
> >>
> >> Sorry, about that short and quick instruction, but I have not much time
> >> at the moment.
> >>
> >> ~DR0ID
> >
> > No problem, any help is appreciated! Does RenderUpdateGroup read from
> > lists, though?
>
> Hi again
>
> well, the pygame.sprite.RenderUpdates is like your list, it is a
> container for sprites. I would inherit from Sprite to make the Bullet:
>
> class myBullet(pygame.sprite.Sprite):
>     def __init__(self):
>           pygame.sprite.Sprite.__init__(self)
>           ....
>
> Then in your code you do:
>
> #instanciate Render group
> rg = pygame.sprite.RenderUpdates()
> # add some Bullets
> for i in range(100):
>     rg.add( myBullet() )
>
> # in main loop, to draw all bullet in rg
> rg.clear()
> rg.update()
> dirty_rects = rg.draw(screen)
> pygame.display.update(dirty_rects)
>
> Naturally any Bullet in the group will be updated and drawen on screen.
> I would just instanciate a new Bullet when needed and add it to the rg
> group (so it get visible). If you need to go through the bullet (for
> collisions detection for example) you can use rg.sprites() which returns
> a list with the bullet sprites.
>
> I hope that helps a better. I hope I havent told you something incorect,
> because it is a while I have used the pygame.sprite groups.
>
> ~DR0ID

now THAT'S some good information. I owe you  one too, DR0ID!