Server Replication

I have been spending the past two weeks re-factoring the server for our game - Starbound Aces. It is in an attempt to move to a more authoritative server model for the game to prevent cheating and game-play issues due to players being out of sync. The biggest improvement I have made is translating and rotating object on the server and sending the new positions to the players. With the aid of the LWJGL and the Apache Math3 API, I was able to imitate the original Unity C# scripts we had for movement onto the server in Java.

Here is the source code for that:

package com.gspteama.gamedriver;



import org.apache.commons.math3.geometry.euclidean.threed.Rotation;

import org.apache.commons.math3.geometry.euclidean.threed.RotationOrder;

import org.lwjgl.util.vector.Matrix4f;

import org.lwjgl.util.vector.Vector3f;

import org.lwjgl.util.vector.Vector4f;



public class Movement{

    public float Velocity;

    public float Acceleration;

    

    private float maxVelocity;

    

    protected Vector3f position = new Vector3f();

    protected Vector3f rotation = new Vector3f();

    protected Vector4f quaternion = new Vector4f();

    

    protected static final Vector3f UP = new Vector3f(0.0f, 1.0f, 0.0f);

    protected static final Vector3f LEFT = new Vector3f(-1.0f, 0.0f, 0.0f);

    protected static final Vector3f FORWARD = new Vector3f(0.0f,0.0f, 1.0f);

    

    protected Matrix4f transform = new Matrix4f();

    

    public void onUpdate(float deltaTime){

        Velocity = Velocity + Acceleration * deltaTime;

        if(Velocity >= maxVelocity){

            Velocity = maxVelocity;

        }

        

        Rotation rotator = new Rotation(RotationOrder.XYZ, rotation.getX(),

                rotation.getY(),

                rotation.getZ());

        quaternion = new Vector4f((float)rotator.getQ0(), 

                (float)rotator.getQ1(),

                (float)rotator.getQ2(), 

                (float)rotator.getQ3());

        

        transform.setIdentity();

        

        transform = transform.translate(position);

        transform = transform.rotate(rotation.getY(), UP);

        transform = transform.rotate(rotation.getX(), LEFT);

        transform = transform.rotate(rotation.getZ(), FORWARD);

        transform = transform.scale(new Vector3f(1.0f,  1.0f, 1.0f));

        

        //to row major

        transform.transpose();

        

        //get the forward vector

        Vector3f forward = new Vector3f(transform.m20,

                                        transform.m21,

                                        transform.m22);

        forward.normalise();

                                        

        Vector3f forwardVel = new Vector3f(forward.getX() * Velocity,

                                            forward.getY() * Velocity,

                                            forward.getZ() * Velocity);

        

        position = Vector3f.add(position, forwardVel, position);

    }



    public Movement(float maxVelocity){

        this.maxVelocity = maxVelocity;

        Velocity = 0.0f;

        Acceleration = 0.0f;

        transform.setIdentity();

    }

    

    public void onLeft(float value){//A

        rotation.y += value;

    }

    

    public void onRight(float value){//D

        onLeft(value);

    }

    

    public void onUp(float value){//W

        Acceleration += value;

    }

    

    public void onDown(float value){//S

        Acceleration -= value;

    }

    

    public void onHorizontal(float value){//MouseX

        rotation.z += value;

    }

    

    public void onVertical(float value){//MouseY

        rotation.x += value;

    }

    

    public float[] getPosition(){

        return new float[]{position.getX(),

            position.getY(),

            position.getZ()

        };

    }

    

    public float[] getQuaternion(){

        return new float[]{quaternion.getX(),

            quaternion.getY(),

            quaternion.getZ(),

            quaternion.getW()

        };

    }

}