Here you can find the source of interpolate(double oldP, double newP, float partialTicks)
public static double interpolate(double oldP, double newP, float partialTicks)
//package com.java2s; //License from project: Open Source License public class Main { public static double interpolate(double oldP, double newP, float partialTicks) { if (oldP == newP) { return oldP; }//from w w w. j a va 2 s . c o m return oldP + ((newP - oldP) * partialTicks); } }