| Description |
Returns the dot product of this vector and another.
The dot product value is in fact the cosine of the angle
between the two input vectors, multiplied by the lengths
of those vectors. So, you can easily calculate the cosine
of the angle by either, making sure that your two vectors
are both of length 1, or dividing the dot product by the
lengths.
cos( theta ) = dot( v1, v2 ) / ( magnitude( v1 ) * magnitude( v2 ) )
Values range from 1 to -1. If the two input vectors are
pointing in the same direction, then the return value will
be 1. If the two input vectors are pointing in opposite
directions, then the return value will be -1. If the two
input vectors are at right angles, then the return value
will be 0. So, in effect, it is telling you how similar
the two vectors are. |
| Examples |
import point2line.*;
Vect2 right = new Vect2( radians( 0 ) );
Vect2 down = new Vect2( radians( 90 ) );
Vect2 left = new Vect2( radians( 180 ) );
Vect2 up = new Vect2( radians( 270 ) );
Vect2 almostRight = new Vect2( radians( 10 ) );
println( Vect2.dot( almostRight, right ) ); // prints "0.9848077"
println( Vect2.dot( almostRight, down ) ); // prints "0.17364813"
println( Vect2.dot( almostRight, left ) ); // prints "-0.9848077"
println( Vect2.dot( almostRight, up ) ); // prints "-0.17364816"
|