Normalize a vector - Java java.lang

Java examples for java.lang:Math Vector

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Description

Normalize a vector

Demo Code

/**/*from  w w w  . j  av  a 2  s  .c  o  m*/
 * Copyright 2010 JogAmp Community. All rights reserved.
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 *       provided with the distribution.
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 * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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 */
import java.util.ArrayList;

public class Main{
    /**
     * Normalize a vector
     * @param result output vector, may be vector (in-place)
     * @param vector input vector
     * @return normalized output vector
     * @return result vector for chaining
     */
    public static float[] normalizeVec2(final float[] result,
            final float[] vector) {
        final float lengthSq = normSquareVec2(vector);
        if (isZero(lengthSq, EPSILON)) {
            result[0] = 0f;
            result[1] = 0f;
        } else {
            final float invSqr = 1f / sqrt(lengthSq);
            result[0] = vector[0] * invSqr;
            result[1] = vector[1] * invSqr;
        }
        return result;
    }
    /**
     * Normalize a vector in place
     * @param vector input vector
     * @return normalized output vector
     */
    public static float[] normalizeVec2(final float[] vector) {
        final float lengthSq = normSquareVec2(vector);
        if (isZero(lengthSq, EPSILON)) {
            vector[0] = 0f;
            vector[1] = 0f;
        } else {
            final float invSqr = 1f / sqrt(lengthSq);
            vector[0] *= invSqr;
            vector[1] *= invSqr;
        }
        return vector;
    }
    /**
     * Return the squared length of a vector, a.k.a the squared <i>norm</i> or squared <i>magnitude</i>
     */
    public static float normSquareVec2(final float[] vec) {
        return vec[0] * vec[0] + vec[1] * vec[1];
    }
    /**
     * Return the squared length of a vector, a.k.a the squared <i>norm</i> or squared <i>magnitude</i>
     */
    public static float normSquareVec2(final float[] vec, final int offset) {
        float v = vec[0 + offset];
        final float r = v * v;
        v = vec[1 + offset];
        return r + v * v;
    }
    /**
     * Return true if all two vector components are zero, i.e. it's their absolute value < <code>epsilon</code>.
     * <p>
     * Implementation uses {@link FloatUtil#isZero(float, float)}, see API doc for details.
     * </p>
     */
    public static boolean isZero(final float x, final float y,
            final float epsilon) {
        return isZero(x, epsilon) && isZero(y, epsilon);
    }
    /**
     * Return true if all three vector components are zero, i.e. it's their absolute value < <code>epsilon</code>.
     * <p>
     * Implementation uses {@link FloatUtil#isZero(float, float)}, see API doc for details.
     * </p>
     */
    public static boolean isZero(final float x, final float y,
            final float z, final float epsilon) {
        return isZero(x, epsilon) && isZero(y, epsilon)
                && isZero(z, epsilon);
    }
}

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