Okay I'm a bit confused with the whole surfaces[i].image I understand how to assign rects and all but what I mean is how would I go about making that class into a list?
On 9/10/07, Ethan Glasser-Camp <[EMAIL PROTECTED]> wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Lamonte Harris wrote: > > class map_: > > def __init__(self,block=100,wndow=(300,300)): > > self.BLOCK = block > > self.size = wndow > > self.map = [] > > self.surfaces = [[],[]] > > self.window = pygame.display.set_mode(self.size) > > pygame.init() > > def create_box(self,size,color,rect): > > box = pygame.Surface((size)) > > pygame.draw.rect(box,color,box.get_rect()) > > self.surfaces[0].append(box) > > self.surfaces[1].append(rect) > > > > Can you explain a little more. > > I can explain a lot more. > > In your code, you have a structure called "surfaces", which is kept in > the map class. This structure is a list with two elements. These two > elements are themselves lists -- the first one is a list of Surface > objects, representing images, and the second one is a list of some > type representing location of these images on-screen. In the code > snippet above, your map "create_box" method adds an image and a > location to this "surfaces" structure. These two things, image and > location, are "paired", in a sense; the image has a location, and > putting a different image at the same location, or putting the same > image at a different location, would be a bug. > > Pairing information in this way is very common in all kinds of > programs, not just games, and there are many mechanisms for showing > this kind of pairing. You have implemented a mechanism which I will > call "parallel arrays"; in order to access an image and its > corresponding location, you look up the same index in two lists > (surfaces[0][i] and surfaces[1][i]). This is a simple mechanism, and > it works fine, but there are some complications. For instance, let's > say you have five images, and five locations. Now you want to delete > an image, but forget to delete its location. Now you have four images > and five locations, and it may not be possible to figure out which > image goes with which location. > > I am proposing the use of another structure, which is called "sprite" > here but can really be called anything, which combines both the image > and the location. If you were to structure your map_ class this way, > instead of having "structures" be a list of two lists, it would be one > list of sprites. To access the image and the location, you would do > surfaces[i].image and surfaces[i].rect. In addition, you no longer > have to worry about deleting all the parts of the sprite object; once > the sprite is removed from the "surfaces" list, it's gone, not > "half-there" like in the hypothetical "forgot to delete something" case. > > There is more to pygame sprites, but the reason I suggested you use > them is that they keep the image and its location together. > > This is the "why". The "how" is outlined in the code I sent -- it > creates one sprite, and uses its "image" and "rect" attributes to > simplify moving it around onscreen (in an admittedly trivial way). As > it applies to your own code you can probably figure out on your own. > > HTH, > > Ethan > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.6 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org > > iD8DBQFG5hRXhRlgoLPrRPwRAkA+AKC2ys7nnDAbdX6Gd3NzVTf0eIZH2QCdFZK2 > G9xndlCnp/vvSqr+Hb8K9vY= > =lAFx > -----END PGP SIGNATURE----- >
