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18. September 2017

Click here for the previous section in this tutorial.

Time for the exact same process as pin and lane, except this time rename the RigidBody to BowlingBallRigidBody. The major differences are we used a SphereShape for our collision shape.

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Plus, in physics, in addition to setting Sleep off, and Contact Listener on, we increase the Mass to 3. The value doesn’t really matter, this just means our bowling ball is 3x heavier than the pins.

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Just for now lets get things rolling (ugh… the puns) and give our ball some initial velocity, so when we play our game, things happen. We will override this in a bit when we implement user control. Simply set the velocity to -15 or so on the Z axis:

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Now when you play the game, if you’ve done everything correctly, the ball should roll down the lane and hit the pins.

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Almost there! Now let’s add some audio that happens when the ball hits a pin. It’s the exact same process as back when we created our title screen, so I’m not going to go over it again. Just be sure to add the SamplePlayer to the bowling ball like so:

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Then go in and create a sample library and add our bowling ball sound effect, in my case Hit.wav.

Now it’s time to do a bit of coding. The BowlingBall is going to be the heart of our game, so let’s add the script to it. Using the same process as back in the title screen, select the BowlingBall root node and attach a new script. Now select the child BowlingBallRigidBody node, switch to the Node tab, select body_enter and hit the Connect button at the bottom right hand corner.

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Another window will pop up asking you which node to connect to. Select our BowlingBall node then click Connect.

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This will open up the script editor and create a new function for us. Inside the function enter the following code:

func _on_BowlingBall_body_enter( body ):
	var name = body.get_name()
	if name == "PinBody":
		self.get_node("SamplePlayer").play("Hit")

Now when you play the scene, when the bowling ball hits the pins, audio should play!

Handling User Input

** Before you continue… go back to the bowling ball and remove the Linear velocity we added earlier! We are going to handle that manually from this point on! **

Next we need to give the user some control over the bowling ball. First off, we need to create an Input map. We are going to use left and right arrows for moving the ball, well… left and right. Additionally, the space bar will be used to throw the ball.

Go to the Scene -> Project Settings Menu, then switch to the Input Map tab. Now we are going to add an entry. Simply enter LEFT in the text box, then click Add:

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Click the + Icon, then select Key

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When prompted, press the Left arrow key

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Now repeat this process for Right and Space. You can of course map multiple keys to a single ID, so if you wanted LEFT to also trigger when the A key is pressed, or on Left mouse click, you can. Now lets wire our script up to handle input. Simply add or replace the following in your BowlingBall script:

func _ready():
	set_process_input(true)

func _input(event):
	if(event.is_action_released("LEFT")):
		self.get_node("BowlingBallRigidBody").apply_impulse(Vector3(0,0,0),Vector3(-1,0,0))

	if(event.is_action_released("RIGHT")):
		self.get_node("BowlingBallRigidBody").apply_impulse(Vector3(0,0,0),Vector3(1,0,0))
		
	if(event.is_action_released("SPACE")):
		self.get_node("BowlingBallRigidBody").apply_impulse(Vector3(0,0,0),Vector3(0,0,-35))

Great, we can now control our ball, have collisions with pins and audio plays. We are 99% of the way toward a finished game… only one catch… you can only play once… that’s a bit of an issue no? Let’s do a quick and direct reset by reloading the scene when the user presses the R key. Add RESET to the InputMap and append the following code to your _input() function:

	if(event.is_action_released("RESET")):
		get_tree().reload_current_scene()

And our final complete code should look like:

extends Spatial

func _ready():
	set_process_input(true)
	set_process(true)

func _input(event):
	if(event.is_action_released("LEFT")):
		self.get_node("BowlingBallRigidBody").apply_impulse(Vector3(0,0,0),Vector3(-1,0,0))

	if(event.is_action_released("RIGHT")):
		self.get_node("BowlingBallRigidBody").apply_impulse(Vector3(0,0,0),Vector3(1,0,0))
		
	if(event.is_action_released("SPACE")):
		self.get_node("BowlingBallRigidBody").apply_impulse(Vector3(0,0,0),Vector3(0,0,-35))

	if(event.is_action_released("RESET")):
		get_tree().reload_current_scene()

		
func _on_BowlingBallRigidBody_body_enter( body ):
	var name = body.get_name()
	if name == "PinRigidBody":
		self.get_node("SamplePlayer").play("Hit")


And all done, one complete if primitive bowling game!  Once again, here is the video version.

Programming , ,

7. August 2017


With the upcoming release of Godot 3.0, Visual Programming is now officially part of the game engine.  In this tutorial we are going to look at the basics of programming using the new Visual Programming interface.


To get started using Visual Programming, just like using GDScript or other options, you have to attach a script to an object in Godot, like so:

image


In the script creation dialog, you can now select the programming language to use:

image


It will now bring you to the following programming interface:

image


To get started, we need to implement one of the available Godot callbacks.  These are exactly the same as GDScript and represent various different functions that will be called over time by the game engine.  To get started, in the Members section, click the following icon:

image


The various different callback functions available for the selected object type are available:

image


The most commonly used callbacks are _process() which is called every pass through the game loop, _ready() which is called when the object has been created, _init() which is called to create the object (think constructor), and _input() which is called when input is received.  We are going to create an exceedingly simple example here that moves our sprite each from, so select _process.  Now you should see:

image


White arrows represent program flow.  Connections on the right represent output, while connections on the left represent input.  This is the entry point for our code and is going to be called each frame.  You can see we are passed a floating point value “delta” as a parameter.  Now we need to get a reference to our object, we use a “self” node for this.  You can locate notes via search:

g1


This gives us access to the Sprite object our script is attached.

image


Now click on the blue/green ball output from the Sprite and drag a connection out, selecting Get as the option:

g2


This will now give you access to all of the data of a sprite object and all other inherited classes:

image


Locate and select position, which is a Vector2 object.  Now lets create a variable we are going to use to define our move amount.  In the variables section, click +:

image


Now right click and select Edit Variable:

image


Select type as Vector2 and value of (1,0)

image

Finally click the variable name and rename it to moveBy.  Now drag our newly created variable onto the canvas:

image


Now we want to create an Add node and add our two vectors together, like so:

image


Now we use another Self (or the same one we created earlier) and this time do a Set and select position.  We now pass in the added Vector2 result, also we attach program flow from _process, like so:

image


This simple program will cause the sprite to move by 1 pixel per update.


Video Version

Programming ,

5. July 2017


There are a wealth of great add-ons for the Godot game engine, such as Add_Primitives, which adds several geometric primitives to the Godot editor, such as capsules, spheres and more.  This quick tutorial (including a video) goes step by step through the process of enabling an add-on in your Godot project.


First, you need to download the add-on you wish to enable, that or git clone it.  In this tutorial we are going to simply download it.  This link will download the add_primitives add-on zip.


Next, create a project.  Add-on’s are now located at the project level, not in the %APPDATA% folder.  In the project directory, create a folder called Addons.  In that folder, extract the zip file you downloaded earlier.  Next be sure to rename it from add_primitives-master to add_primitives, so the folder name matches the add-on name.  If you cloned using git, you wont have to perform this step.


Now load Godot.  Select the Scene Menu->Project Settings.

image


Switch to the Plugins tab

image


Next change Status to Active.

image


And done!  If you are using the Add_Primitives add-on from this example, you should now see an additional icon in the 3D view:

image


The Add-on will also be shown in your project view:

image


You can watch the above process in video form below.

Programming , ,

29. June 2017


In this section of our Bowling with Game Engines series, we will be implementing our bowling game in Unity. The idea is straight forward, implement the same simple 3D game across a number of game engines.  The Unity game engine is a logical place to start, as it is perhaps the most popular game engine in use today.  We will go step by step through the process of creating our game, both in text as well as a video version available here.   I am not a regular Unity user, so please do keep in mind, a lot of what I am about to show may not be best practice!  All of the assets used in this tutorial are available for Patreons as part of the bowling game kit, along with project files and this document in PDF form.  Don’t worry, these aren’t needed to follow along.

Let’s jump in.  Fire up Unity and create a new project.  In this example I am using Unity 5.6.1, however any recent version should work.


First, let’s start by dragging all of our required assets into Unity.  Simply select all of the game assets you will be using (FBX models, textures, audio files) and drag and drop them from Explorer or Finder into the assets folder.  If you are using the Patreon assets, simply copy the contents of Raw Assets in the Unity project folder.

clip_image002[4]


Unity does an extremely good job of importing assets and you should require no additional steps.  We now have all of the assets we are going to need to create our game, let’s get started.




Creating the Title Screen


First, we are going to start by creating a simple title screen with some awful looping background music.  We will be using our default scene for the splash screen and later we will create another scene for our actual gameplay.  We start off by saving our untitled scene.  Simply select File->Save Scene As…

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I saved it as TitleScreen. You should now have a new item in your assets list:

clip_image006[4]


We now have a few setup tasks to take.  We are going to be showing our title image and this requires us to alter the Main Camera entity. In Hierarchy panel select Main Camera, then in Inspector we change Clear Flags to Don’t Clear.

clip_image008[4]

This causes our camera to no longer have perspective ( things aren’t drawn smaller the farther away they get from the camera ).  Generally an Orthographic camera is what you use when working in 2D in a 3D world. Setting Clear Flags to don’t clear simply causes the default skybox to not be drawn, we could have optionally defined a background clear colour if we preferred. 


Now in Hierarchy panel, click the Create button, select UI->Canvas.  Next, with the newly created Canvas selected, click Create again and this time select UI->Panel.  At this point we should have this hierarchy.

clip_image010[4]


Next we have to make a slight modification to our imported Titlescreen image.  Select the Tilescreen.png image file in the assets view, then in Inspector change Texture Type to Sprite (2D and UI).  Then scroll down in the Inspector and click the Apply button.

clip_image012[4] 


Next select Panel in the Hierarchy view, and drag our newly created Sprite over to the Source Image section in the Image (Script) section.

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If you press Play now, you should see your Title screen in the viewport.

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Now let’s add a looping music file to our title screen.  In the Hierarchy view, select the Canvas entity.  Then in inspector scroll down and click Add Component, then Audio->Audio Source.

clip_image018[4]


In the newly created Audio Source in Inspector, drag our imported audio file over to the audio clip section.  Down below, make sure Play on Awake is set and then tick the box next to Loop.

clip_image020[4]


Ok, we now have a title screen and a sound track playing!  Good work so far… now let’s add a simple script that changes scenes on click. Let’s create our script.  Right click in the Assets area, select Create-> C# Script.

clip_image022[4]


Name it PanelScript.cs.

clip_image024[4]


Double click the newly created script file and it will open in your editor of choice.  Now enter the following code:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;

public class PanelScript : MonoBehaviour {

   // Use this for initialization
   void Start () {
      
   }
   
   // Update is called once per frame
   void Update () {
        if (Input.GetMouseButtonUp(0))
            SceneManager.LoadScene("GameScene");
    }
}


Here we are simply checking every single pass through the game loop if the Left (0th) mouse button (or touch) is clicked, and if it is, we load the scene named “GameScene”.


Hmm… guess we should make a scene called GameScene now shouldn’t we?  Once again right click the Assets panel, then select Create->Scene.

clip_image026[4]


Rename the newly created Scene to GameScene.

clip_image028[4]


We are now done with our title screen scene.  Make sure you save.  Before we open our newly created GameScene, we have one last step to perform.  In the File menu, select Build Settings…, then select Add Open Scenes.

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Now double click our newly created GameScene to open it up.  If prompted to save, do so.  Now it’s time to create our game!


Click here to continue to part two!

Programming , , ,

29. June 2017

Click here for Part One

Creating the Game Scene


Now it’s time to get to work on creating the game itself.  Start off by dragging BowlingLane into the scene.

clip_image002


Now move the lane so it’s at position (0,0,0) in the Inspector under the Transform component.

clip_image004


One thing I noticed is the Normal map is way too strong.  Select the Bowling Lane material (either in the Materials panel, or drill down to it).  Dial back the Normal Map strength from 1.0 to 0.2.

clip_image006


We are almost done with our bowling lane.  The final thing we need to do is add a Collision Shape to it, so the rest of the stuff in our game world will interact with it properly.  With the BowlingLane selected, click Add Component->Physics->Box Collider

clip_image008


The nice thing with Unity is, it will automatically shrink wrap the collider geometry to match your mesh, so you should have to do no additional work!

clip_image010


So, that’s it for the lane, now time to create the Bowling pins.  Simply drag the Bowling Pin into the scene:

clip_image012


Hmmmm… pretty dark. What’s going on here?  Well, right now we are getting our lighting from the Directional Light in our scene.

clip_image014


We don’t want to mess around with advanced lighting, so instead right click and get rid of it. Now lets set up Ambient lighting instead.  Select Window->Lighting->Settings

clip_image016


Change Environment Lighting->Light Source to Color, then select the Ambient Color as white:

clip_image018


Now our scene will have universal consistent lighting:

clip_image020


Now it’s time to add some physics to our pin.  Once again we have to make a collision object component, but we also need to create a RigidBody component.  Add a Box collider just like before.  Then add another Component and select Physics->Rigidbody

clip_image022

The default settings are about right, so there is nothing else we need to do here.


The final thing we need to do with our pin is apply a tag to it so we can locate it using code later. With the Pin selected, in the Inspector at the top drop down the Tag drop down and select Add Tag…

clip_image024


Click the + Icon, then in the resulting text box enter “Pin” then Save.

clip_image026


Now select the Pin again, and in the Tags list, select Pin which should now be an option.

clip_image028


Now we simply need to create 4 ( or 9… depending your bowling preferences ) clones of our pin. Select the BowlingPin in the scene graph, right click and select Duplicate.  This will create a copy with all of the settings and components defined. 

clip_image030


After duplicating, position the pin and repeat the process until you have enough pins.

clip_image032


Click here to continue to part three.

Programming , , ,

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