This will check if two lines collide. - Java java.lang

Java examples for java.lang:Math Geometry Line

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Description

This will check if two lines collide.

Demo Code


//package com.java2s;

import java.awt.geom.Point2D.Double;

public class Main {
    /**/* ww  w  . ja v  a2 s  .co  m*/
     * This will check if two lines collide. It will return the collision point
     * which is null if their is no collision.
     * 
     * @param x1
     *            the x position of the first line firsts point.
     * @param y1
     *            the y position of the first line firsts point.
     * @param x2
     *            the x position of the first line second point.
     * @param y2
     *            the y position of the first line second point.
     * @param x3
     *            the x position of the second line firsts point.
     * @param y3
     *            the y position of the second line firsts point.
     * @param x4
     *            the x position of the second line second point.
     * @param y4
     *            the y position of the second line second point.
     * @return the collision point which can be null.
     */
    public static Double lineIntersect(double x1, double y1, double x2,
            double y2, double x3, double y3, double x4, double y4) {

        double denom = (y4 - y3) * (x2 - x1) - (x4 - x3) * (y2 - y1);

        if (denom == 0.0)
            return null;

        double ua = ((x4 - x3) * (y1 - y3) - (y4 - y3) * (x1 - x3)) / denom;
        double ub = ((x2 - x1) * (y1 - y3) - (y2 - y1) * (x1 - x3)) / denom;
        if (ua >= 0.0f && ua <= 1.0f && ub >= 0.0f && ub <= 1.0f)
            return new Double((x1 + ua * (x2 - x1)), (y1 + ua * (y2 - y1)));

        return null;
    }
}

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