Math question: How to compute the area of polygons
Jim Hurley
jhurley at infostations.com
Thu Mar 20 07:13:01 EST 2003
>
>
>On Wednesday, March 19, 2003, at 10:47 AM, Jim Hurley wrote:
>
>> But you have to do this for each line segment pair. If there are n
>> line segments in one sprite and m in the other, there will be n*m
>> potential intersections. Heavy!!!
>>
>> If it were me, I would just fake it by calling it a collision if the
>> distances between their centers (locs) are less than a specified
>> number. But I am a person of loose morals.
>Dar Scott wrote:
>And I tend to legalistic.
>
>There may be a way to mix styles. If we limit our attention to the
>intersection of the bounding rectangles of the two polygons, then we
>can eliminate those line segments that do not intersect or are
>otherwise not "near" the intersection rectangle. In the worse case
>this is more work, but on the average it should be less "heavy". Use
>your "loose morals" to come up with "near".
>
(snip)
Dar,
You have obviously given this a lot of thought! And I'm sure you are
right about a two pronged approach being the right one: First check
to see if the locs are close enough that it is *possible* for the two
polygon boundaries to intersect, and, if so, then check to see if
any of the line segments do indeed intersect; this would define a
collision.
Jim
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