hitTest has a version that tests a point against the actual shape of a
MovieClip. The other varaiation tests two MovieClips, but only compares
their bounding boxes, not the actual shapes.
I found a useful segment intersection algorithm in the book
_Computational Geometry: Algorithms and Applications_, by Mark de Berg
http://www.amazon.com/Computational-Geometry-Algorithms-Applications-Second/dp/3540656200/ref=pd_ys_qtk_rvi_img/102-1020427-4119337
which I bought (will be shipped tomorrow).
The algorithm is quite understandable and efficient. It does use binary
trees, so I have to code a binary tree class before I can implement the
algorithm. I guess that is good practice for me because I just started
doing AS 2.0 OOP stuff. (I did C++ in the Bad Old Days, so I am not an OO
neophyte, but the bad old days were a long time ago. I don't even think
design patterns were invented. If they were, they were not taught at my
university.)
ObGripe: I was impatient so I also bought the online electronic edition ($10
after buying the book at regular price) from Amazon and was able to get the
algorithm I needed (good explanation with background, discussion of
time/space issues, and pseudocode; no sample source but that's the way I
prefer it). I was annoyed to discover that one has to print the pages in
the e-book one at a time (and they come up slowly -- on DSL -- and print
slowly...) rather than by specifying a range of pages. The ad about the
online book said it was printable, and it never occurred to me that the
printing would be so difficult and slow. Also, the pubisher has a limit on
how many pages you are allowed to print (not specified either, so I guess it
will just stop printing when I reach the limit). Aaagh.
Millie Niss
[EMAIL PROTECTED]
http://www.sporkworld.org
----- Original Message -----
From: "JulianG" <[EMAIL PROTECTED]>
To: "Flashcoders mailing list" <[email protected]>
Sent: Thursday, November 09, 2006 8:00 AM
Subject: Re: [Flashcoders] efficient line segment intersection algorithm?
I think HitTest only works with the bounding box of the MovieClip. So it's
not appropriate for what you're doing.
Try this Metanet Tutorial: Beyond HitTest()
<http://www.harveycartel.org/metanet/tutorials.html> Collision Detection
in Flash.
cheers,
JulianG
Millie Niss wrote:
It occurred to me that possibly hitTest doesn't work to check whether a
point intersects with a clip that has strokes but no fills (ie my
edges)... Does hitTest use the pixels of strokes or does it only use the
insides of fills as the area it checks the test point against?
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