Game Server to Verify Player Actions

[nicktendo]

Would it be possible to create a BabylonJS scene within the context of a NodeJS server simply to recreate the environment of a player and verify valid movement/collisions? The BabylonJS scene on the server would obviously not need to paint anything anywhere, but would simply need to calculate mesh positions/collisions/etc.

[GameMonetize]

Hello I have the plan to work on a headless version of babylon.js that could be used in this scenario:

https://github.com/BabylonJS/Babylon.js/issues/2529

[nicktendo]

@Deltakosh Thank you for the reply

Is there a "hack" way to accomplish this with the current version of BJS?

[nicktendo]

@Deltakosh I came across a thread in which @RaananW suggested simply overriding the render function as such: http://www.babylonjs-playground.com/#1WNTNW

Would this be the best way to run a "headless" version of BJS at current?

[GameMonetize]

This won't work as you still need a canvas to initialize the engine

[nicktendo]

@Deltakosh How about this: https://github.com/Automattic/node-canvas

[GameMonetize]

Don't think either as there is no webgl context

[nicktendo]

@Deltakosh How about this : https://github.com/stackgl/headless-gl 

 

[GameMonetize]

This one looks really promising!

[nicktendo]

@Deltakosh I'll experiment with using headless-gl as the WebGL context for BJS later today and update with my results..

[GameMonetize]

Please do. This would be useful for everyone

[nicktendo]

@Deltakosh A quick update, I've successfully gotten BJS to run within a NodeJS app. The dependencies are as follows:

gl: https://www.npmjs.com/package/gl

canvas: https://www.npmjs.com/package/canvas

jsdom: https://www.npmjs.com/package/jsdom

A version of NodeJS that utilizes Node Module version 48 to be compatible with canvas: https://nodejs.org/en/download/releases/

A few modifications had to be made to Babylon.js:

1. Define the following variables at the top of Babylon.js:

var window = {};
window.location = {};
window.location.href = "";
var navigator = {};

2. Add an argument to the engine constructor to pass a window variable from jsdom:

function Engine(canvas, antialias, nodeWindow, options, adaptToDeviceRatio) {
            window = nodeWindow;
            document = window.document;
            navigator = window.navigator;

3. Comment out the following code inside Effect.prototype._loadVertexShader:

if (vertex instanceof HTMLElement) {
                var vertexCode = BABYLON.Tools.GetDOMTextContent(vertex);
                callback(vertexCode);
                return;
            }

Without this comment an error is thrown when attempting to resolve 'HTMLElement', I'm sure there's a more comprehensive solution to this problem.

Here is the NodeJS app:

var gl = require('gl')(1920, 1080, { preserveDrawingBuffer: true });

var canvas = require('canvas');

const jsdom = require('jsdom');

const { JSDOM } = jsdom;

var BABYLON = require('./babylon.max.js');

 

var dom = new JSDOM();

var window = dom.window;

 

canvas.getContext = function(thecontext,options){

return gl;

}

canvas.addEventListener = function (event,options){

return 1;

}

 

var engine = new BABYLON.Engine(canvas, true, window);

var scene = new BABYLON.Scene(engine);

// Enable Collisions

scene.collisionsEnabled = true;

var camera = new BABYLON.FreeCamera("camera1", new BABYLON.Vector3(0, 5, -10), scene);

var sphere = BABYLON.Mesh.CreateSphere("sphere1", 16, 2, scene);

sphere.checkCollisions = true;

sphere.position.y = 5;

var speed = 0.01;

 

scene.registerBeforeRender(function() {

console.log(sphere.position.x);

sphere.position.x += speed;

});

 

engine.runRenderLoop(function () {

scene.render();

});

 

console.log("ran")

 

As of now the default vertex shader isn't able to be loaded properly, but as this is a headless implementation shaders probably aren't very relevant. I'll ultimately find a permanent solution for this error. I'm sure there is a significant amount of simplification that could be done to the engine implementation overall since it's running in a headless configuration, but this seems to be working for now. I wanted to minimize my modifications to the engine so I could use as close to a duplicate implementation of the browser version as possible  

 

I've attached the NodeJS project files for reference.

babylon.max.js

index.js

 

package.json