Re: [pygame] Directional collision detection.

[B W <stabbingfinger@xxxxxxxxx>]

Enjoy. :) Credit for Struct goes here (with many other savvy tricks
and obscurities):

Python Infrequently Asked Questions
http://norvig.com/python-iaq.html

fin

On Sun, Feb 22, 2009 at 1:58 PM, René Dudfield <renesd@xxxxxxxxx> wrote:
> ps.  I like your Struct class there!  very clever, haven't seen that before.
>
> cu,
>
> On Mon, Feb 23, 2009 at 8:53 AM, B W <stabbingfinger@xxxxxxxxx> wrote:
>> I did the following, which adequately fit my needs. Unfortunately
>> there is some ambiguity to overcome. For example, if one rect is
>> moving at speed 5,5 and the other at -5,-5 their corners will collide.
>> In this case two sides are in contact and you must quantify it in
>> program code to decide which way they should rebound.
>>
>> class Struct(object):
>>    def __init__(self, **entries):
>>        self.__dict__.update(entries)
>>
>> def collide_edges(r, other):
>>    """Detect the edges of rectangle r that collide with rectangle
>>    other. Returns an ad hoc object with boolean attributes left,
>>    right, top, and bottom whose values indicate whether that side
>>    collided."""
>>    Rect = pygame.Rect
>>    side = Struct(left=False, right=False, top=False, bottom=False)
>>    left=Rect(r.left, r.top+1, 1, r.height-2)
>>    right=Rect(r.right, r.top+1, 1, r.height-2)
>>    top=Rect(r.left+1, r.top, r.width-2, 1)
>>    bottom=Rect(r.left+1, r.bottom, r.width-2, 1)
>>    if left.colliderect(other):
>>        side.left = True
>>    if right.colliderect(other):
>>        side.right = True
>>    if bottom.colliderect(other):
>>        side.bottom = True
>>    if top.colliderect(other):
>>        side.top = True
>>    return side
>>
>> if __name__ == '__main__':
>>    pygame.init()
>>    r1 = pygame.Rect(1,1,10,10)
>>    r2 = pygame.Rect(9,9,10,10)
>>    edges = collide_edges(r1, r2)
>>    print '%s: %s' % ('left',edges.left)
>>    print '%s: %s' % ('right',edges.right)
>>    print '%s: %s' % ('top',edges.top)
>>    print '%s: %s' % ('bottom',edges.bottom)
>>
>> fin
>>
>> On Sun, Feb 22, 2009 at 1:21 PM, Daniel Mateos <daniel@xxxxxxxxx> wrote:
>>> Hey,
>>>
>>> Can anyone suggest a good way to do collision detection between two
>>> rects in a way that i can also get the side of the rect that the
>>> collision was detected on.
>>>
>>> --
>>> Daniel Mateos
>>> http://daniel.mateos.cc
>>>
>>>
>>
>