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How to Load a 3D Model for VR with Babylon.JS – Tutorial

Posted by Dr. Burton on January 3, 2019 in Babylon.js, Game Development, Tutorials, WebVR |

I recently began a major project using Babylon.js The reason I selected Babylon.js was the support for browser based game environment (at 60fps), and web-based VR (WebVR).
The first thing I wanted to do was load a 3D model that had been created in Blender. Here is how.

In this tutorial I’m going to quickly cover setting up your development environment and then demonstrate how to load a 3D model that was created in Blender (v.2.8). Make sure you export the final model as a glTF. I prefer the glb format over glTF as it incorporates the entire model, animation, and materials in one file rather than multiple files.

Once you have your model, you will need to decide where you will be testing your script from: a local server or a web server.
For faster iteration, I suggest setting up your development system with a local server. This is now much easier than in the past thanks to Python’s server tools.

To setup a local server, follow the directions on the Mozilla.org site: https://developer.mozilla.org/en-US/docs/Learn/Common_questions/set_up_a_local_testing_server
(Note: I found one error in the Windows directions: use ‘python -m http.server’ to launch your server instead of ‘python3’).

Of course, once you have a model loading, you will want to be able to share it with the rest of the world. I used AWS lightsail and launched a node.js instance to host my files.

Using Filezilla, I was able to quickly upload the html and glb files to the server and share them with the world. The files are stored in the /opt/bitnami/apache2/htdocs folder

Babylon.js can be completely encapsulated within the html document. For this tutorial, we are going to keep it as simple as possible and keep the html and script in the index.html file, only loading the glb file.

The html code is straight forward, loading the babylon framework and the gltf loaders. After the scripts are loaded, we can set the style for the document and the render canvas:

<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

        <title>Sample using Babylon js</title>
        <script src="https://preview.babylonjs.com/gltf_validator.js"></script>
        <script src="https://preview.babylonjs.com/babylon.js"></script>
        <script src="https://preview.babylonjs.com/loaders/babylonjs.loaders.js"></script>
        <style>
            html, body {
                overflow: hidden;
                width: 100%;
                height: 100%;
                margin: 0;
                padding: 0;
            }

            #renderCanvas {
                width: 100%;
                height: 100%;
                touch-action: none;
            }
        </style>
    </head>

Now that we have the header taken care of, we can jump into the body. First we need to create a canvas and then create a function that will store the scene. Once the function is declared, we can setup the scene:

<body>
   <canvas id="renderCanvas"></canvas>
   <script>
      var canvas = document.getElementById("renderCanvas");

      var createScene = function() {
         // Create scene
         var scene = new BABYLON.Scene(engine);

Next we will setup the default environment, enabling shadows on the ground. We will also turn on the VR option, so that anyone who has VR googles can see the object in VR.

         // Default Environment
         var environment = scene.createDefaultEnvironment({ enableGroundShadow: true, groundYBias: 1 });
    
        // Enable VR
        var vrHelper = scene.createDefaultVRExperience({createDeviceOrientationCamera:false});
        vrHelper.enableTeleportation({floorMeshes: [environment.ground]});

Now let’s get to the fun part; loading the model!
We are going to use the BABYLON.SceneLoader.Append command to make this happen. This allows us to load add the model to an existing scene. We will also set the camera and lights so that we can see everything.

        var building = BABYLON.SceneLoader.Append("./", "VRChapel.glb", scene, function (meshes) {    
            scene.createDefaultCameraOrLight(true, true, true); 
            }); 

There is a lot happening with the Append command, so let’s break it down:

The 1st parameter – “./” – provides the location or folder of the file to be loaded. In this case the glb file is in the same folder.
The 2nd parameter “VRChapel.glb” the model to be loaded. If you saved your file as a glTF, only the model will be loaded, no textures, materials, or animations.
The 3rd parameter tells the engine where to load the model too, in this case the scene.
The 4th parameter is a function to create the camera and lights for the scene.

Finally, we return the scene and launch the engine. Notice the at the scene is describe before the engine is launched.

        return scene;
      };
               
      var engine = new BABYLON.Engine(canvas, true, { preserveDrawingBuffer: true, stencil: true });
      var scene = createScene();

Finally, we add a rendering loop, handle window resizing, and close the html page:

        engine.runRenderLoop(function () {
            if (scene) {
                scene.render();
            }
        });

        // Resize
        window.addEventListener("resize", function () {
            engine.resize();
        });
    </script>
</body>
</html>

And there you have the minimum code to load a 3D model in Babylon.JS.
Of course, there is SO much more that we can (and will) do with this environment. This is just the starting point.

Special thanks to Adrianna Mott for the model! You can see the results of this tutorial online at: http://vrchapel.me/Tutorial1-loadModel.html

The only problem at this point is the skybox which is a little small and located inside the building. We will address that in the next tutorial.

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How to Fill a Picker Wheel from a SQLite Database in Corona SDK – Tutorial

Posted by Dr. Burton on December 16, 2018 in Android, Corona, iPad, iPhone, Kindle Fire, Lua, Mobile, Tutorials |

Last semester I had a group of students using Corona SDK who were using a database to list local establishments.  They needed a way to easily display the list of locations in the SQLite database to the application.
While I had discussed the possibility of reading from a database and loading a picker-wheel in the textbooks Learning Mobile Application & Game Development and Beginning Mobile App Development with Corona, these students were relatively new to app development and needed a little more guidance on the process.

So, without further background, here is how to load a picker-wheel from a local SQLite database in Corona SDK.

To get started we will need to load the required plugins for sqlite and the picker-wheel widget tool in Corona.  We will also make sure that the database is in the documents folder of the mobile device and not the resource folder.

*Note: I have created a database that lists all cities in the USA by zip code.  I will be using it for this demonstration.

require("sqlite3")
local widget = require "widget"

-- Does the database exist in the documents directory (allows updating and persistence)
local path = system.pathForFile("zip.sqlite", system.DocumentsDirectory )
file = io.open( path, "r" )
   if( file == nil )then           
   -- Doesn't Already Exist, So Copy it In From Resource Directory                          
   	pathSource = system.pathForFile( "zip.sqlite", system.ResourceDirectory )  
   	fileSource = io.open( pathSource, "rb" ) 
   	contentsSource = fileSource:read( "*a" )                                  
		--Write Destination File in Documents Directory                                  
		pathDest = system.pathForFile( "zip.sqlite", system.DocumentsDirectory )                 
		fileDest = io.open( pathDest, "wb" )                 
		fileDest:write( contentsSource )                 
		 -- Done                      
		io.close( fileSource )        
		io.close( fileDest )         
   end   
-- One Way or Another The Database File Exists Now -- So Open Database Connection         
db = sqlite3.open( path )

-- handle the applicationExit event to close the db
local function onSystemEvent( event )
	if( event.type == "applicationExit") then
		db:close()
	end
end

A quick note on the copy method.  When you are working on a Windows system for development, you MUST use the “rb” (read binary) and “wb” (write binary) methods for reading and writing a database.  This forces Corona to copy the file in the binary format.  On a Mac, you can do a regular “r” and “w”.  For greatest compatibility, we recommend always using rb and wb to avoid premature greying and extensive head-smashing-into-desk.

Time to load the data from the database.   To begin, create a table to store the data loaded from the database (click here to see my tutorial on tables). 
Next, create the SQL statement to load records from the database.  I have limited the SQL statement to the first 20 records for simplicity (there are 1000’s of records). 
After reading each row of data and creating a variable to store the city & state captured from the database, we add the text to the data table that will be used by our picker-wheel.

local data = {}
local sql = "SELECT * FROM zipcode LIMIT 20"
for row in db:nrows(sql) do
local text = row.city..", "..row.state
table.insert(data, text)
end

Time to create the picker-wheel.  We are going to keep it simple; just one column of data that contains the city and state information.
The picker-wheel will be 258 pixels from the top of the screen (for no real reason, just looked good on my test app), with a font size of 18 and a default color of black.  The currently selected city & state will be red.

--Create storage for picker wheel
local columnData = { {align = "left", startIndex = 3, labels=data } }

-- create the picker widget with columnData
local picker = widget.newPickerWheel({
    top=258,
    fontSize = 18,
    fontColor={0,0,0},
    fontColorSelected = { 1, 0, 0 },
    columnColor = { 0.8, 0.8, 0.8 },
    columns = columnData,
})

Just three more things to do: add a button to return the selected data to the console, setup the function to print the selected value, and finally, add a event listener to close the database if the user abruptly closes the app.


local function showValues( event )
		-- Retrieve the current values from the picker
		local values = picker:getValues()
		
		-- print the selected values
		print( "Column Information: " .. values[1].value )		
end	

local getValuesButton = widget.newButton
	{
	    left = 10,
	    top = 150,
		width = 298,
		height = 56,
		id = "getValues",
	    label = "Values",
	    onRelease = showValues,
	}	

-- system listener for applicationExit
Runtime:addEventListener ("system", onSystemEvent)

And that is how you load a picker-wheel from a local SQLite database. This tutorial has been added to the Corona textbooks available on our website.
FYI, the students did a great job on their project!

If you would like the video tutorial of working with a Picker wheel and SQLite, checkout the link below!

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Reflections on Personalized Education

Posted by Dr. Burton on May 30, 2018 in Deep Learning, Education, Technology |

Traditional education assumes a transmissive format of instruction.  With #VR we can leave behind the traditional “sage-on-the-stage” and enable new #epistemology approaches, enabling learners to experience #education instead of trying to recall it from a lecture. When we begin to include #AI agents, #bigdata; when we are creating true #personalizededucation that adapts to the needs of the student, then we are accomplishing what generations of educators have sought to accomplish.

 

 

More to come, this is just the beginning!!

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Certbot Not Renewing

Posted by Dr. Burton on March 17, 2018 in Cloud Computing, Technology, WordPress |

First, this post is more for me as a reminder should I have this problem again. But, if it helps you resolve your problem, yea!

Problem (tl;dr version): Certbot didn’t update the ssl certificates on one of my servers, resulting in ugly messages about the websites not being safe.

Long Version: I’m hosting my own sites on Amazon EC2 servers running AMI flavor of Linux. About a year ago I upgraded from standard webpages to ssl to make Google and other search engines happy. Everything was going fine until recently when the site didn’t renew the certificates for SSL from Let’s Encrypt.

While I had followed the Amazon tutorial exactly (https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/SSL-on-an-instance.html#letsencrypt) Certbot wasn’t running any longer. After troubleshooting, I found that it was a common problem with the latest versions of certbot. There were a lot of solutions provided by various people, none worked correctly. What did work is:

Solution:
On the github website (https://github.com/certbot/certbot/issues/1680#issuecomment-358728515) I found a solution that worked:
sudo rm -rf /opt/eff.org/*
pip install -U certbot
sudo certbot renew –-debug

I did have to make one change since I was using the -auto version of certbot:
sudo ./certbot-auto renew –-debug

Now the solutions is available should I (or anyone else) need it!

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Lumberyard, Lua, Corona Projects Update

Posted by Dr. Burton on July 12, 2017 in Amazon Lumberyard, Corona, Game Development, Lua, Lumberyard |

We have been working on serveral major projects at Burtons Media Group. We thought we would take a moment and provide an update on individual status of the projects:

Amazon Lumberyard Game Development Fundamentals: Space Explorer

The textbook is mostly complete with the exception of the final chapter where we cover visual scripting. We are semi-patiently awaiting the release of Lumberyard 1.10.  This update promises to be a major one with the inclusion of Script Canvas, Amazon Lumberyard’s visual scripting tool set.  Expect to see the release of this textbook and associated on-demand video course soon after the 1.10 release.

Corona Development On-Demand Course

The on-demand course is in active development with completely new and updated videos and content.  While based upon our Learning Mobile Applicaition & Game Development and Beginning Mobile App Development textbooks, we are adding additional lessons to make this a great value above and beyond the textbooks.  We will be providing a discount if you previously purchased on of the Corona Textbooks.

Work continues on the isometric game development book.  We will be using the Million Tile Engine plugin to handle much of the heavy lifing and focus on the isometric game development process in this textbook.

Learning Lua

Lua seems to be at the center of every project that we develop.  While it was not intentional, it has definitly become the “need to know” scripting language at BMG.  To that end we have started developing a textbook and on-demand course content on Lua that will cover everything from the basics through using Lua for Machine Learning (Torch) and implementing Lua as a part of an engine.

Burton Institute of Technology

We at Burtons Media Group were recently asked when we would begin to provide on-demand training for Lumberyard, Corona, and Lua.  In the past we have focused on digital-print (i.e. pdf and ePub) plus making games.
As we surveyed the landscape (and with Dr. Burton’s extensive knowledge of online learning) we have decided to begin actively developing online certificate courses.  Production has already begun and you can expect to see BIT courses via the BurtonsMediaGroup.com website in the very near future.

 

 

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