/* * Simulation.java *  * Created on 26/10/2007 *  * To change this template, choose Tools | Templates * and open the template in the editor. */package demos.nehe.lesson40;/** * Java implementation of Erkin Tunca's "Simulation" class from "Physics1.h" by Scott Rains.<br/> * Date: 26 Oct 2007 * * @author Scott Rains (sid.rains[at]gmail.com) */public class Simulation {    int numOfMasses;                            // number of masses in this container    protected Mass[] masses;                                                // masses are held by pointer to pointer. (Here Mass** represents a 1 dimensional array)    public Simulation(int numOfMasses, float m) {        this.numOfMasses = numOfMasses;        masses = new Mass[numOfMasses];                                 // Create an array of pointers        for (int a = 0; a < numOfMasses; a++) {                         // We Will Step To Every Pointer In The Array.            masses[a] = new Mass(m);                                // Create A Mass As A Pointer And Put It In The Array.        }    }    public Mass getMass(int index) {        if (index < 0 || index >= numOfMasses)                          // if the index is not in the array        {            return null;                        // then return NULL        }        return masses[index];                        // get the mass at the index    }    public void init() {        for (int a = 0; a < numOfMasses; ++a) {                         // We will init() every mass            masses[a].init();                                       // call init() method of the mass        }    }    public void solve() {        // no implementation because no forces are wanted in this basic container        // in advanced containers, this method will be overridden and some forces will act on masses    }    public void simulate(float dt) {        for (int a = 0; a < numOfMasses; ++a) {                         // We will iterate every mass            masses[a].simulate(dt);                                 // Iterate the mass and obtain new position and new velocity        }    }    public void operate(float dt) {        init();                                                         // Step 1: reset forces to zero        solve();                                                        // Step 2: apply forces        simulate(dt);                                                   // Step 3: iterate the masses by the change in time    }}