Java atan2 squareAtan2(float y, float x)

Description

Calculates the square angle corresponding with the given direction.

License

Open Source License

Parameter

Parameter	Description
y	The y coordinate of the given direction.
x	The x coordinate of the given direction.

Return

The square angle corresponding with the given direction.

Declaration

public static float squareAtan2(float y, float x) 

Method Source Code

//package com.java2s;
/*/*ww w. j  a  v  a 2s. co m*/
 * Copyright (c) 2015 Sam Johnson
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

public class Main {
    /**
     * Calculates the square angle corresponding with the given direction.
     * 
     * @param y The y coordinate of the given direction.
     * @param x The x coordinate of the given direction.
     * @return The square angle corresponding with the given direction.
     */
    public static float squareAtan2(float y, float x) {
        float squareLength = Math.max(Math.abs(x), Math.abs(y));
        y /= squareLength;
        x /= squareLength;

        int signs = (x < 0.0f ? 1 : 0) | (y < 0.0f ? 2 : 0);

        switch (signs) {
        case 0:
            return -x + y + 1.0f; //(+, +)
        case 1:
            return -x - y + 3.0f; //(-, +)
        case 2:
            return x + y + 7.0f; //(+, -)
        case 3:
            return x - y + 5.0f; //(-, -)
        default:
            assert false : signs; //Shouldn't happen.
            return Float.NaN;
        }
    }

    /**
     * Returns the greater of the two given values. Does not check for negative
     * zero or NaN.
     * 
     * @param x0 Any float.
     * @param x1 Any float.
     * @return The greater of the two given values.
     */
    public static float max(float x0, float x1) {
        return x0 >= x1 ? x0 : x1;
    }
}

Related

1. atan2(double[] arr1, double[] arr2)
2. atan2(final double y, final double x)
3. atan2(float y, float x)
4. atan2(Integer y, Integer x)
5. atan2Scalar(double val, double[] arr)