Return the angle between to vectors in radians - Java java.lang

Java examples for java.lang:Math Vector

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Description

Return the angle between to vectors in radians

Demo Code

/**//from www.j ava  2s.  co  m
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import java.util.ArrayList;

public class Main{
    /**
     * Return the angle between to vectors in radians
     * @param vec1 vector 1
     * @param vec2 vector 2
     */
    public static float angleVec3(final float[] vec1, final float[] vec2) {
        return FloatUtil.acos(cosAngleVec3(vec1, vec2));
    }
    /**
     * Return the cosines of the angle between to vectors
     * @param vec1 vector 1
     * @param vec2 vector 2
     */
    public static float cosAngleVec3(final float[] vec1, final float[] vec2) {
        return dotVec3(vec1, vec2) / (normVec3(vec1) * normVec3(vec2));
    }
    /**
     * Return the dot product of two points
     * @param vec1 vector 1
     * @param vec2 vector 2
     * @return the dot product as float
     */
    public static float dotVec3(final float[] vec1, final float[] vec2) {
        return vec1[0] * vec2[0] + vec1[1] * vec2[1] + vec1[2] * vec2[2];
    }
    /**
     * Return the length of a vector, a.k.a the <i>norm</i> or <i>magnitude</i>
     */
    public static float normVec3(final float[] vec) {
        return FloatUtil.sqrt(normSquareVec3(vec));
    }
    /**
     * Return the squared length of a vector, a.k.a the squared <i>norm</i> or squared <i>magnitude</i>
     */
    public static float normSquareVec3(final float[] vec) {
        return vec[0] * vec[0] + vec[1] * vec[1] + vec[2] * vec[2];
    }
    /**
     * Return the squared length of a vector, a.k.a the squared <i>norm</i> or squared <i>magnitude</i>
     */
    public static float normSquareVec3(final float[] vec, final int offset) {
        float v = vec[0 + offset];
        float r = v * v;
        v = vec[1 + offset];
        r += v * v;
        v = vec[2 + offset];
        return r + v * v;
    }
}

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