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From: dave@viper.Lynx.MN.Org (David Messer)
Newsgroups: comp.graphics
Subject: Re: Stupid Beginner Question, but I am stuck!
Message-ID: <4092@viper.Lynx.MN.Org>
Date: 9 Nov 90 02:57:28 GMT
References: <35558@cup.portal.com>
Reply-To: dave@viper.Lynx.MN.Org (David Messer)
Organization: Lynx Data Systems, Eagan, MN
Lines: 18

In article <35558@cup.portal.com> Bobster@cup.portal.com (Robert Jules Shaughnessy) writes:
 >
 >  I am having troubles finding the angle from one point on a 2D plane to
 >another. For instance at point A, what direction would I need to go to hit
 >point B, in degrees.
 >  I do have something that works, I take the ATN of x1-x2/y1-y2 and this 
 >works ok, but will only show 90 degrees.

There is a function in the standard C library called atan2()
that handles this (call as "angle = atan2( x1-x2, y1-y2 )" ).

If you don't have the standard C functions, writing this
shouldn't be particularly difficult.  The CRC Standard Math
Tables book is a good place to start for information on
formulas.
-- 
How can you tell if Bush is lying?   | David Messer       dave@Lynx.MN.Org -or-
      Watch his lips...              | Lynx Data Systems  ...!bungia!viper!dave