Re: [pygame] Fastest (x,y) distance calculation

[Rene Dudfield <illumen@yahoo.com>]

Zak Arntson wrote:
... cut stuff about distance calculation.


This is pretty cool.
http://www.ifm.liu.se/~ulfek/projects/SCAM-current/doc/SCAM.html

ODE through pyode also supports collision detection.


Here's a couple of functions which you can quickly cut the number of 
entities to check against in two.

def get_unique_pairs(vals):
   """ finds unique combinations from a given list of values.
        Which doesn't include combinations with itself.
   """
   vals_cpy = vals
   pairs = []
   pairs_extend = pairs.extend

   while vals_cpy:
      
       vals_head = vals_cpy[0]
       vals_cpy = vals_cpy[1:]

       new_ones = map(lambda x:(vals_head,x), vals_cpy)
       pairs_extend(new_ones)

   return pairs


def get_to_collide(vals):
   """ Returns a dict keyed by one of the vals, valued by a
        list of the vals which to check collisions against.
   """
   vals_cpy = vals
   tocollide = {}

   while vals_cpy:
       vals_head = vals_cpy[0]
       vals_cpy = vals_cpy[1:]

       if vals_cpy:
           tocollide[vals_head] = vals_cpy

   return tocollide


Have fun!