[gameprogrammer] Re: Diff Between 2 Angles
- From: "Matthew Weigel" <unique@xxxxxxxxxxx>
- To: gameprogrammer@xxxxxxxxxxxxx
- Date: Fri, 30 Sep 2005 15:28:05 -0500 (CDT)
Sami Näätänen wrote:
> On Friday 30 September 2005 10:08, Olof Bjarnason wrote:
>> double absanglediff(double angle1, double angle2) {
>> // Rotate angle1 with angle2 so that the sought after
>> // angle is between the resulting angle and the x-axis
>> angle1 -= angle2;
>>
>> // "Normalize" angle1 to range [-180,180)
>> while(angle1 < -180)
>> angle1 += 360;
>> while(angle1 >= 180)
>
> small improvment is to left out the equal sign.
> after all abs(180-360) == abs(180)
Changing '>=' to '>' is better for a completely different reason: angle1
is a double, and equality is basically meaningless for floating point
numbers.
If the angles were integers, '>=' would be very appropriate so that you
are left with exactly 360 degrees - switching it to '>' would leave two
equivalent cases in the domain that could queer debugging, and maybe other
things.
--
Matthew Weigel
hacker
unique@xxxxxxxxxxx
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