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21. February 2017

 

Somewhat delayed from the rest of the Defold Engine tutorial series, I realized there was a major gap in subjects we covered... GUI programming.  Defold actually has some really solid UI functionality built in, and in this tutorial we are going to look at the basics of handling a UI in Defold. Well very conventional in it’s approach, if you’ve gotten accustomed to the Defold way of doing things, you will find Defold’s approach to handling UI remarkably consistent to the way you do just about everything else using the Defold game engine.

 

As always, there is an HD video version of this tutorial available here.

 

In this tutorial we are going to implement the simplest of UI, but all of the concepts of a much more complicated interface can easily be extrapolated from what we cover here. We are going to create a UI that pops up when the user hits the ESC key, dimming the existing screen, showing the UI, handling input, then un-dimming the UI.  There is a ton more UI functionality available in Defold, but it should be fairly easy to pick it up once you’ve got the basics down.  So without further ado, lets jump right in.

 

A UI in Defold consists of two different file types, a .gui and a .gui_script file.  A gui_script file is just a traditional lua script file, but has access to the gui namespace.    Let’s take a step by step look at creating a UI that appears when you hit the ESC key and handles a simple button being clicked.

 

First we need a font, drag any applicable TTF file to your project.  I personally created a folder called MyFont and dragged it there.  Next I created a Font file in the same folder.

image

 

Next open the newly created Font file and select the ttf file you just imported.  Please note that the filter is broken and you should manually type *.ttf to locate your font.

image

After selecting the font I also increased the size to 30pts.  This is aesthetic and purely optional.

 

Now that we have a font selected, we need to define an Input map.  I fully describe the process here for more information on how Input Maps work in Defold.  This are the bindings I created:

image

 

Next we create our gui file.  Simply select Gui File:

image

 

We can use the Gui File to arrange the controls that make up our UI.  Here are the options:

image

 

In this simple UI we are simply going to create a button by creating a box then adding a text label to it.  We will also create a label telling the user to click the button.  First we need to set up our font that we created earlier.  In the GUI editor, right click Fonts and select Add Font:

image

 

When prompted, select the font you just created:

image

 

Now right click Nodes and add a Box.  Once created it can be positioned by hitting W then moving manually.

TransformBox

 

Next right click the newly created box node and create a child Text field:

image

 

Child nodes automatically inherit the position of their parents.  With the Text node selected, lets set it’s font and text, like so:

image

 

I also created another Text field telling the user to click the button.  This one in the root of the GUI hierarchy and not parented to the box.  You’re outline should look something like:

image

 

While your Gui layout should look something like:

image

 

Now that we have a gui file, let’s right a script that will display it.  In our main.collection I simply create a new script and attach it to the default logo objecct.

image

 

Now of course we need to add the UI to our game object.  Create a new root level GameObject named UI, then add component from file and select our gui file:

image

 

So now you main.collection should look something like:

image

Now we enter the following code for main.script:

function init(self)
	-- we want focus and to hide our UI until needed
    msg.post(".", "acquire_input_focus")
    msg.post("UI","disable");
end


function on_message(self, message_id, message, sender)
	-- Wait for a message from the UI layer that the UI has been dismissed
	-- un-dim our sprite
    if(message_id == hash("DONE_UI")) then
    	go.set("#sprite","tint.w",1.0)
    end
end

function on_input(self, action_id, action)
	-- If the user hits the ESC show the UI and dim our sprite
    if(action_id == hash("ESC") and action.released) then
    	-- UI needed now, reenable
    	msg.post("UI","enable")
    	go.set("#sprite","tint.w",0.2)
	end
end

 

This code does a couple things, first on input it tells Defold we want to get input messages.  We also start out by disabling the UI, by sending it the built-in message disable.  When the user actually hits the escape key, we send a message to re-enable the UI layer.  We also dim the logo sprite so it’s not visually in focus when the UI is active.  Also note we wait for the DONE_UI message to undim our sprite.  This is sent by the UI script, which we will create now.

 

If you select your .gui file, in the properties you will notice there is a setting for Script.

image

 

There is a special kind of script, .gui_script, that is used to control gui objects, the Gui Script File.  Let’s create one in the same folder as our .gui file:

image

 

This is a standard lua script, but it has access to the gui namespace.  Once you’ve created your gui_script, set it as the script for your gui file.  Now enter the following script:

function init(self)
	-- We want input control.  AKA, pump input to the UI
    msg.post(".", "acquire_input_focus")
    
end

function on_message(self, message_id, message, sender)
	-- Expect to be enabled by main when needed.  Acquire focus and set text back to click me
	if(message_id == hash("enable")) then 
		msg.post(".", "acquire_input_focus")
		gui.set_text(gui.get_node("text"),"Click Me")
	end
end

function on_input(self, action_id, action)
	-- handle left clicks.  On left click, see if click was within box
	-- if so change our text (this wont actually be seen), disable ourself and pass a message back
	-- to logo that we are done so it can undim itself
	if(action_id == hash("LEFT_CLICK") and action.released == true) then
		local box = gui.get_node("box")
		if(gui.pick_node(box,action.x,action.y)) then
			local text = gui.get_node("text")
			gui.set_text(text,"Clicked")
			msg.post(".","disable")
			msg.post(".","release_input_focus")
			msg.post("/logo",hash("DONE_UI"))
			
		end
	end
end

 

This code waits for the enable message then sets input focus so the gui can receive input messages from Defold.  It also illustrates how you could change the text of a component within the gui.  The most important logic is in the on_input event handler.  We wait for the LEFT_CLICK input.  We then check to see if the click was within our box, if so we set the text of our control ( which is somewhat pointless as it’s about to be hidden! ) to “Clicked”, disable our self, release input focus then send the message DONE_UI back to main.script.  Now if you run the code:

GIF

 

Of course we only scratched the surface of what you can do in a Defold gui, but that should certainly get you started!

 

The Video

Programming , ,

6. February 2017

 

In our previous tutorial we materials in our ongoing Babylon Tutorial Series but today we are going to take things a step higher up and let someone else worry about doing the work for us.  Today we will look at exporting 3D models from Blender for use in our game.  A number of exporters exist (3ds Max, FBX, Cheetah, Unity), but today we are specifically going to talk about using Blender.

First we need to download and install the plugin.  Fortunately they make a zip version available for download.  Head on over to https://github.com/BabylonJS/Babylon.js/blob/master/Exporters/Blender/Blender2Babylon-5.2.zip and click Download:

image

 

Save the zip file somewhere you will remember.  Now fire up Blender.  Select File->User Preferences…  then select the Add-Ons tab

image

 

Now choose Install From File… and select the newly downloaded zip.  Then in the filter area type “Bab” and Import-Export: Babylon.js should be available.  Simply check the checkbox to the right hand side to enable it.  We can now export our scene as a .babylon file for use in our game.  Simply select File->Export->Babylon.js:

image

 

There are no settings for the exporter, so simply pick your game asset directory and click Export Babylon.js Scene.  A .Babylon file and all of your textures will be created in your selected save location:

image

 

Now let’s look at the code required to load and display this model in our game:

    window.addEventListener('DOMContentLoaded', function(){
        var canvas = document.getElementById('canvas');

        var engine = new BABYLON.Engine(canvas, true);
        engine.enableOfflineSupport = false; // Dont require a manifest file
        var createScene = function(){
            var scene = new BABYLON.Scene(engine);
            scene.clearColor = new BABYLON.Color3.White();


            var camera = new BABYLON.ArcRotateCamera("arcCam",
                    BABYLON.Tools.ToRadians(0),
                    BABYLON.Tools.ToRadians(0),
                    10.0,BABYLON.Vector3.Zero(),scene);
            camera.attachControl(canvas,true);
            var light = new BABYLON.PointLight("PointLight",new BABYLON.Vector3(
            0,0,0),scene);
            light.parent = camera;
            light.intensity = 1.5;

            BABYLON.SceneLoader.ImportMesh("","","ShippingContainer.babylon",
            scene,function(newMeshes) {
                newMeshes.forEach(function(mesh){
                    mesh.rotation = new BABYLON.Vector3(BABYLON.Tools.ToRadians(
                    45),0,0);
                }                );
            });

            return scene;
        }

        var scene = createScene();
        engine.runRenderLoop(function(){
            scene.render();
        });

    });

 

The magic is done using the Y() function call.  You can load a specific asset from within the .babylon file by specifying it’s name, but in this case we just want the whole thing.  Import mesh has a callback when the mesh is loaded ( it’s loaded async, so you need to use this callback ) and it’s passed an array of Mesh objects.  We simply loop through this array ( in this example it’s only one item long, so we could have just as easily done newMeshes[0] and accomplished the same thing ).  Sometimes you will need to reposition your objects when loaded due to different coordinate systems, this example shows rotating each mesh by 45 degrees along the X axis.

 

This example uses the ShippingContainer blend file available as part of the Patreon dropbox assets, but you can use any applicable Blend file to create the example.  If you are a Patreon support (thanks by the way!) you can find this model in Art\Blender\ShippingContainer and the code is all available (including the exported Babylon file) in Tutorial Series\Babylon\5 - PartFive – Models.

 

When we run this example, we should see:

GIF

 

The Video

Programming, Art , , , ,

18. January 2017

 

In our previous tutorial we covered lighting in our ongoing Babylon Tutorial Series but the objects in our game are still remarkably drab.  A big part of this is the lack of materials applied to them.  In this tutorial we are looking at using the StandardMaterial which handles all the grunt work for you.  You can think of StandardMaterial as a container for several different kinds of textures (diffuse, opacity, etc. ) that can be applied to an object.  It also has some built in attributes such as diffuse (color), emissive (self lighting) and more.  Let’s start straight away with an example that we covered in a previous tutorial.  Applying a simply wireframe to our cube:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../Common/Lib/babylon.max.js"></script>

    <style>

        #canvas {
            width:100%;
            height:100%;
        }
    </style>
</head>
<body>
<canvas id="canvas"></canvas>
<script>
    window.addEventListener('DOMContentLoaded', function(){
        var canvas = document.getElementById('canvas');

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

        var createScene = function(){
            var scene = new BABYLON.Scene(engine);
            scene.clearColor = new BABYLON.Color3.White();
            var box = BABYLON.Mesh.CreateBox("Box",4.0,scene);
            var camera = new BABYLON.ArcRotateCamera("arcCam",
                    BABYLON.Tools.ToRadians(45),
                    BABYLON.Tools.ToRadians(45),
                    10.0,box.position,scene);

            camera.attachControl(canvas,true);

            var material = new BABYLON.StandardMaterial("material1",scene);
            material.wireframe = true;
            box.material = material;

            return scene;
        }

        var scene = createScene();
        engine.runRenderLoop(function(){
            scene.render();
        });

    });
</script>
</body>
</html>

 

When you run it:

image

 

Simple enough.  We create a StandardMaterial, passing in it’s identity and the scene to create it in.  We set the materials wireframe property to true, then apply the material to our object’s material property.  Note each object can only have a single material, although a compound material exists if you need to mix multiple materials together.  Now let’s look at a slightly more colourful example, this time using more of the built in properties of StandardMaterial.

 

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../Common/Lib/babylon.max.js"></script>

    <style>

        #canvas {
            width:100%;
            height:100%;
        }
    </style>
</head>
<body>
<canvas id="canvas"></canvas>
<script>
    window.addEventListener('DOMContentLoaded', function(){
        var canvas = document.getElementById('canvas');

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

        var createScene = function(){
            var scene = new BABYLON.Scene(engine);
            scene.clearColor = new BABYLON.Color3.White();
            var box = BABYLON.Mesh.CreateBox("Box",4.0,scene);

            var camera = new BABYLON.ArcRotateCamera("arcCam",
                    BABYLON.Tools.ToRadians(45),
                    BABYLON.Tools.ToRadians(45),
                    10.0,box.position,scene);

            camera.attachControl(canvas,true);

            var light = new BABYLON.PointLight("pointLight",new BABYLON.Vector3(
            5,5,0),scene);
            light.diffuse = new BABYLON.Color3(1,1,1);



            var material = new BABYLON.StandardMaterial("material1",scene);
            material.diffuseColor = BABYLON.Color3.Blue();
            material.emissiveColor = BABYLON.Color3.Red();

            material.specularColor = BABYLON.Color3.Red();
            material.specularPower = 3;
            material.alpha = 1.0;
            box.material = material;

            var plane = BABYLON.Mesh.CreatePlane("plane", 10.0, scene, false, 
            BABYLON.Mesh.DOUBLESIDE);
            plane.material = new BABYLON.StandardMaterial("material2",scene);
            plane.material.diffuseColor = new BABYLON.Color3.White();
            plane.material.backFaceCulling = false;
            plane.position = new BABYLON.Vector3(0,0,-5);

            return scene;
        }

        var scene = createScene();
        engine.runRenderLoop(function(){
            var material = scene.getMeshByName("Box").material;
//            material.alpha -= 0.01;
//            if(material.alpha < 0) material.alpha = 1.0;
            scene.render();
        });

    });
</script>
</body>
</html>

Running this example results in:

image

 

Here you can see we’ve set the diffuse, emissive and specular values of the cube.  I also created a plane so you can see the emissive value of our cube has no effect on it.  The diffuse property can be thought of as the colour in the traditional sense.  Emissive on the other hand is a value for an internal light of the material, there aren’t actually that many emissive parallels in the real world, but some mosses and a few creatures have an emissive property to them.  Specular color determines how external light sources interact with the surface.  If you look at the commented code in the main loop you will also see commented code affecting the alpha channel of the material.  Alpha can be thought of transparency, with a value of 1 being fully opaque, while 0 is fully transparent.

What the majority of people think of when they work with materials is textures.  Textures are simply images that are applied the surface of an object like virtual wallpaper.  There are different types of textures as well, some effect the color of a surface, others affect the transparency or normals.  Here is an example:

<script>
    window.addEventListener('DOMContentLoaded', function(){
        var canvas = document.getElementById('canvas');

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

        var createScene = function(){
            var scene = new BABYLON.Scene(engine);
            scene.clearColor = new BABYLON.Color3.White();
            var box = BABYLON.Mesh.CreateBox("Box",4.0,scene);
            var camera = new BABYLON.ArcRotateCamera("arcCam",
                    BABYLON.Tools.ToRadians(45),
                    BABYLON.Tools.ToRadians(45),
                    10.0,box.position,scene);

            camera.attachControl(canvas,true);

            var light = new BABYLON.PointLight("pointLight",new BABYLON.Vector3(
            0,10,0),scene);
            light.parent = camera;
            light.diffuse = new BABYLON.Color3(1,1,1);


            var material = new BABYLON.StandardMaterial("material1",scene);

            material.diffuseTexture = new BABYLON.Texture("gfs.png",scene);
            material.bumpTexture = new BABYLON.Texture("gfs_normal.png",scene);
            material.roughness = 0.5;
            box.material = material;



            return scene;
        }

        var scene = createScene();
        engine.runRenderLoop(function(){

            scene.render();
        });

    });
</script>

 

And when you run it:

image

 

This example uses two different textures, a diffuse texture:

gfs

 

And a normal map:

gfs_normal

 

For more details on Normal Maps, check this video on Normal Map 101.  Somewhat confusingly, BabylonJS refers to normal maps as bump textures.  This only scratches the surface of the material and texture options available, you also have options like ambient, opacity, reflection, light and specular textures, but you will find they almost all work exactly the same way.

Programming , , ,

12. January 2017

 

Today we are going to take a quick look at the Tilengine 2D game engine.  Tilengine in their own words is:

Tilengine is a free, cross-platform 2D graphics engine for creating classic/retro games with tilemaps, sprites and palettes. Its unique scanline-based rendering algorithm makes raster effects a core feature, a technique used by many games running on real 2D graphics chips.Untitled 3

Tilengine is open source (sorry, the core isn't open ), available on Github however I never could locate what license it’s released under.

EDIT—Since posted, there has been a bit of conversation about the licensing since this was posted, read here.

  It’s a C library, but contains bindings for Python, C# and Java.  I’m actually going to use the C# bindings for the example in this review as it’s the least documented of the available bindings.  There is a single page class reference available here and a small manual available here.  The engine is geared towards creating retro sprite style games and handles graphics, animations, palettes, input and window management, but has no sound or physics engine built in.  It is also designed to be used as a backend solution to an existing front end renderer.  There are several C based examples available here, and this represents the primary way you will get up to speed.  The graphics system is designed to emulate classic sprite systems like Sega’s SuperScaler arcade board but with Super Nintendo’s Mode 7 style graphics effects available.  Tilengine is layered over SDL and is cross platform, capable of running on most desktop operating systems, as well as Raspberry Pi devices.

Tilengine is composed like so:

image

 

Tilengine has direct support for tiled map files created using the Tiled map editor.  If you want to learn more about Tiled, I have done a complete tutorial series available here.

 

As a pretty straight forward game engine, let’s jump right in with the example created using the C# bindings:

using Tilengine;

namespace ConsoleApplication
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var engine = Tilengine.Engine.Init(320,240,1,16,16);
            var window = Tilengine.Window.Create("",Tilengine.WindowFlags.Vsync);
            
            // This is the clear color drawn each frame.  Think of it as the sky color
            engine.BackgroundColor = new Color(0,128,238);

            // Load tsx and tmx file.  These are created in the Tiled level editor
            // tsx is a collection of tiles, tmx is a map painted using those tiles
            var tileset = Tileset.FromFile("SOTB_bg.tsx");
            var tilemap = Tilemap.FromFile("SOTB_bg.tmx","Layer 1");
            
            // create a new layer using our just loaded tiles.  Games can have multiple layers
            var layer = new Layer();
            layer.Setup(tileset,tilemap);
            layer.SetPosition(0,0);

            
            // Now we are loading an animated sprite riped from the 90s classic Shadow of the Beast
            // Spriteset is simply the image collection composing our game Spriteset
            // SequencePack is simple text format describing the available animations, their frames, speed etc
            // While Sequence is a named entry in the SequencePack text file
            Spriteset ss = Spriteset.FromFile("SOTB");
            SequencePack sp = SequencePack.FromFile("SOTB.sqx");
            Sequence walk = sp.Find("walk");

            // Now finally create a sprite using our spritesheet
            Sprite sprite = new Sprite();
            sprite.Setup(ss,TileFlags.None);

            int spriteX = 15;
            sprite.SetPosition(15,215);
            
            // Now play the animation sequence named "walk".  We also pass the final 0 in to tell it how many times the animation
            // should loop.  Zero equals forever
            Animation anim = new Animation();
            anim.SetSpriteAnimation(0,walk,0);
            
            
            int frame = 0;

            // This is your game loop
            while(window.Process()){
                // Draw the current frame of graphics (sprites, layers, etc)
                window.DrawFrame(frame++);

                // Now check if left or right arrow/gamepad are pressed, in which case move in that direction
                // IF moving left, flip the sprite over on the X axis
                if(window.GetInput(Input.Right)){
                    spriteX ++;
                    sprite.Flags = TileFlags.None; 
                }
                if(window.GetInput(Input.Left)){
                    spriteX --;
                    sprite.Flags = TileFlags.FlipX; 

                }
                sprite.SetPosition(spriteX, 185);
                if(spriteX > engine.Width) spriteX = 0;
            }
            

            //Cleanup
            tilemap.Delete();
            tileset.Delete();
            window.Delete();
            engine.Deinit();
        }
    }
}

 

The comments pretty much describe everything that is going on there.  For more details, be sure to check the video version of this tutorial available here [coming soon].  This example loads a sprite and animation from the game Shadow of the Beast, an Amiga platformer classic.  The SequencePack file format is extremely simple XML file, here is the example used:

<?xml version="1.0" encoding="UTF-8"?>

<sequences>
  <sequence name="walk" delay="6" loop="0">
    1,2,3,4,5,6
  </sequence>
</sequences>

 

The tsx and tmx files are generated using the Tiled level editor, another open source and free tool.  As you can see, it’s extremely simple to get up and going.  Run this code you will see:

SOTB

 

This is of course a primitive example, but does show the many parts of a game.  A game loop, sprite loading, animations, level loading, etc.  The major features of the engine, that I’m not covering here, are the various sprite effects it emulates.  You can see these effects demonstrated here or in the samples.

 

The Video

Programming , , ,

2. January 2017

 

In our previous tutorial in the BabylonJS Tutorial Series we covered positioning a camera in our world.  There were still a few fundamental components missing, the top of which is lighting which we are going to cover today.  Lights are used to, predictably enough, illuminate your scene.  They interact with the color and materials on your various entities that compose your scene.  There are multiple different light types available in BabylonJS including the Point Light, Directional Light, Spot Light and Hemispherical light.  A point light is a single light source that radiates in all directions, like a naked lightbulb for example.  A directional light in a radiates just in the direction it is pointed and it goes on forever with no fall off basically illuminating everything in its path regardless to distance.  A spot light is similar to a directional light but it does fall off over a given distance and is cone shaped.  A flashlight is a classic example of a spot light, as of course is a spot (or search) light!.  A hemispherical light is generally used to represent an ever present ambient light source, the sun being perhaps the most common example.  You can also emit light from textures using their emission property, but we will cover that at a later point.  In this tutorial we are going to implement a point and a spot light.

 

There is an HD video version of this tutorial available here.

 

Let’s start with a point light.  It’s a simple light that radiates from a single point (thus the name) in all directions.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../Common/Lib/babylon.max.js"></script>

    <style>

        #canvas {
            width:100%;
            height:100%;
        }
    </style>
</head>
<body>
<canvas id="canvas"></canvas>
<script>
    window.addEventListener('DOMContentLoaded', function(){
        var canvas = document.getElementById('canvas');

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

        var createScene = function(){
            var scene = new BABYLON.Scene(engine);
            scene.clearColor = new BABYLON.Color3.White();

            var box = BABYLON.Mesh.CreateBox("Box",4.0,scene);
            var camera = new BABYLON.ArcRotateCamera("arcCam",
                    BABYLON.Tools.ToRadians(45),
                    BABYLON.Tools.ToRadians(45),
                    10.0,box.position,scene);
            camera.attachControl(canvas,true);

            var light = new BABYLON.PointLight("pointLight",new BABYLON.Vector3(
            0,10,0),scene);
            light.diffuse = new BABYLON.Color3(1,0,0);


            scene.actionManager = new BABYLON.ActionManager(scene);
            scene.actionManager.registerAction(
                    new BABYLON.ExecuteCodeAction({ trigger:
                            BABYLON.ActionManager.OnKeyUpTrigger, parameter: " " 
                            },
                            function () {
                                light.setEnabled(!light.isEnabled());
                            }
                    ));

            return scene;
        }

        var scene = createScene();
        engine.runRenderLoop(function(){
            var light = scene.getLightByName("pointLight");
            light.diffuse.g += 0.01;
            light.diffuse.b += 0.01;
            scene.render();
        });

    });
</script>
</body>
</html>

 

There are a couple things illustrated in this example.  Creating a point light is done by calling new BABYLON.PointLight(), passing in the ID of the light, the position of the light in the world and finally the scene in which the light exists.  You can set the color of the light by setting it’s diffuse property, in this case we set it to full red only.  You will notice this example also shows a new concept in BabylonJS, the ActionManager.  This is a way of wiring code to specific events.  In this case we add some code that will be fired when the space key is pressed.  That function simply turns off and on the light source by calling setEnabled() passing a true or false value.  In the render loop we also slowly increase the lights green and blue components, so you can see the effect of diffuse lighting on the scene.  When you run this code you should see:

GIF

 

Lights are implemented as part of the GLSL shader process and the active lights in the scene are passed to each StandardMaterial in the scene.  By default the standard material is limited to a maximum of four active lights.  This value can be overridden using the maxSimultaneousLights property of the StandardMaterial, although this may have some impact on performance, especially on mobile targets.

 

Next lets look at implementing a spot light.  As with all things BabylonJS, the process is quite similar:

<script>
    window.addEventListener('DOMContentLoaded', function(){
        var canvas = document.getElementById('canvas');

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

        var createScene = function(){
            var scene = new BABYLON.Scene(engine);
            scene.clearColor = new BABYLON.Color3.White();

            var box = BABYLON.Mesh.CreateBox("Box",4.0,scene);
            var camera = new BABYLON.ArcRotateCamera("arcCam",
                    BABYLON.Tools.ToRadians(45),
                    BABYLON.Tools.ToRadians(45),
                    10.0,box.position,scene);
            camera.attachControl(canvas,true);

            var light = new BABYLON.SpotLight("spotLight",new BABYLON.Vector3(0,
            10,0),new BABYLON.Vector3(0,-1,0),
                    BABYLON.Tools.ToRadians(45), // degrees the light fans out
                    0.1, // falloff/decay of the light over distance
                    scene);

            return scene;
        }

        var scene = createScene();
        engine.runRenderLoop(function(){
            var light = scene.getLightByName("spotLight");
            light.position.y -= 0.01;
            scene.render();
        });

    });
</script>

 

In this example we create the spot light with a call to new BABYLON.SpotLight, passing in the id, position, direction vector, the degrees or arc of the light cone, the rate the light falls off over distance and finally the scene to create the light in.  In this example instead of changing the color of the light each frame, we instead move it slightly.  Run this code and you should see:

GIF2

 

As the light is pulled back the fall off cone is quite prominently displayed.  Of course the lack of textures makes this example more than a bit stark, so that is what we will cover in the next tutorial.

 

The Video

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