Here you can find the source of lerp(double amt, double start, double end)
public static double lerp(double amt, double start, double end)
//package com.java2s; //License from project: LGPL public class Main { public static double lerp(double amt, double start, double end) { if (amt <= 0.0D) { return start; }//ww w. j a v a2s . c o m if (amt >= 1.0D) { return end; } return start + (end - start) * amt; } }