XRCC Tutorial - Pinball

Overview

You will build an interactive Pinball Machine using XRCC in this tutorial. This tutorial will focus on using the XRCC's physics features to create the pinball game, you will learn how to use physics settings and physics-type behaviour blocks to create a physics-based game. This is an advanced level XRCC tutorial, if it's your first time using the XRCC, we recommend that you finish tutorials 1 - 2 first.

Techniques Covered

You will learn the following techniques in this tutorial:

Technique	Specific Techniques Covered
Using Physics Setting & Behaviour	Using constraints to limit physics calculation Using the Add Force Physics behaviour
Advanced Behaviour Setting	Using Start Contact block Get and set variables Using Flow Control behaviour blocks Constructing and using Behaviour Actions

Tutorial Project

The project used for this tutorial comes in two formats: a starter project for use in this step-by-step tutorial, and a completed project for your reference after you've completed the tutorial.

Project files for the pinball tutorial can be found at:

Download Project

Project files for the Pinball tutorial can be download here

For this tutorial, the starter project will be used to guide you build the Pinball Machine in a step-by-step manner. All the necessary assets required for the tutorial are already included in the project, so just open the starter project in XRCC and you are ready to go with the tutorial.

A complimentary video for this tutorial is available from the below link to assist your learning process:

Gameplay Flow

1. The player press the "Shoot" button to launch the ball into play.

2. As the ball moves inside the machine, the player's score can be increased by 1 for each contact with bumpers and slingshots.

3. The player need to deflect the ball from preventing the ball falling out of play by pressing "Rotate" button to control the flippers.

4. If the ball falls through the bottom, the round ends.

Assets Provided in the Starter Project

The starter project for the Pinball tutorial provides a comprehensive set of assets and functionalities to get you started. This includes 3D models of different components of a pinball machine including the playfield, flippers, slingshots, and bumpers.

Enable Physics and Interactable

In this section, you will set up the physics and interactivity settings for the key components of the pinball machine. This includes configuring the ball's physics behavior, setting up static colliders for walls, and making buttons interactive.

Enable Ball Physics

1. First, we select the ball and open the "Inspector". Deselect "Interactable" for it then set its physics setting to "Enable Physics" and "Use Gravity". Finally, freeze the Z position under Constraint.

note

The Z position physics constraint limits the ball's physics movement to only the X and Y direction, so that it won't bounce off the playfield.

Enable Wall Physics

1. We will use the Empty Object as the walls. Select the Empty Objects and open the "Inspector" Then select "Enable Physics" and "Static" under physics setting in the Inspector.

2. Remember to set the Empty Object to be a wall.

Enable Bumpers and Slingshots Physics

1. For the bumpers and the slingshots at the pinball machine middle, we want them to contact the ball and have fixed positions. Select the machine's bumpers and slingshots then open the "Inspector". Select "Enable Physics" and "Static" under physics tab.

Enable Buttons Interactable

1. For each of the buttons, open the "Inspector" and enable Interactable.

Create the Behaviour Flow for Pinball

In this section, you will learn how to create the core gameplay mechanics for a pinball machine. You will implement ball shooting mechanics, flipper controls with proper cooldown timing, and collision behaviors between the ball and various pinball machine elements.

Shooting and Resetting the Ball

1. Open the Ball object's behaviour panel. Under "Group", create an action and rename it to "Shoot". Then toggle the "Action" button to make it an action that can be called by other objects.

2. Then switch to the behaviour Library, under the "Physics" category drag the "Add Force" block and append it behind the "Action Start" block and deselect the "Relative" option, it will add force using the scene's X, Y, Z direction, as opposed to using the Ball object's, which is changing constantly. Add a "Vector3" block to the "Add Force" block's Force node, then set its Y value to 12. When the "Shoot" button is clicked, we add an upward force to the ball.

3. Back to the scene and select "Shoot" button. Open the "Inspector" and select the "Action" option. On the "Select Instance Panel", select the Ball object and choose the "Shoot" action we have just created. Click the "Select" button.

4. We want to add force on the ball when it contact with "Collision1". Open the Ball object's behaviour panel. Under "Library", switch to the "Item Event" category, find and drag the "Start Contact" behaviour block onto the behaviour canvas and select "Collision1" as the "Target". Then switch to the "Physics" category, drag and drop the "Add Force" behaviour block onto the behaviour canvas. Connect the "Start Contact" block's out flow node with the "Add Force" block's in flow node.

   note

   This sets up the behaviour for the ball when it comes into contact with the deflector plate. When the contact happens, we will add a force on top of the ball's physics calculation to amplify the bouncing effect.

5. Add a "Vector3" and a "Random Number" block to the canvas, then connect "Vector3" block with the "Add Force". Set the "Random Number" block to generate a random number between Min -2 and Max -5, and connect it to the "Vector3" block.

   note

   This adds a varied force to the X direction every time the ball touches the deflector, so the ball will drop to different positions for every gameplay.

6. On the Ball object's Main behaviour layer. Add another "Start Contact" block onto the behaviour canvas and select "Trough" as the "Target". Then append a "Set Position" block to it and use a "Vector3" block to set its Target position. Copy the X, Y, Z position of the Ball from the "Inspector" and paste them onto the respective field of the "Vector3" block. This behaviour flow will reset the position of the Ball when it contacts the Trough.

7. Press the "Play" button and test the shooting function by clicking the "Shoot" button. When the ball contact with object "Collision1" it will bounce away. Finally when it touch the object "Trough", the position will be reset.

Hitting the Ball with Flippers

1. Open the left flipper object's behaviour panel.

2. Under "Groups", add a new behaviour group and rename it to "Rotate". Toggle the "Action" button to make it an action that can be called by other objects. An "Action Start" event trigger block will appear on the canvas.

3. Select the "Show Item Variables" button to open the item variables panel. Add a new variable named "rotate", set the variable type to "Boolean" and set its default value to False.

4. For the "Rotate" action, add a "Rotate" block behind the "Action Start", set the "Rotate" Time to 0.1, then use a "Vector3" block to set the rotation Angle. Finally, set the "Vector3" block's Z value to 60.

5. Select both the "Vector3" and "Rotate" blocks, Copy "" (Ctrl + C) and Paste "" (Ctrl + V) or Duplicate (Ctrl + D) them on the canvas.

6. Connect the previous "Rotate" block's out flow node with the copied "Rotate" block's in flow node. Then set the Time on the other "Rotate" block to 0.2 and the Z value of the "Vector3" to -60.

   note

   When this action is called, the left flipper will rotate 60 degrees clockwise for 0.1 seconds and then anticlockwise for 0.2 seconds to its original rotation.

7. Select the "Rotate" button and click the selector next to the Rotate button's "Action" in the "Inspector" and select the Flipper Left object's "Rotate" action to assign the action to the Rotate button.

   note

   This will set up the "Rotate" button to call the "Rotate" action when the button is clicked.

8. Press the "Play" button and test the flippers by clicking the "Rotate" button. The left flipper would rotate and return back to its original state, but its rotation would look off if you click the button too much and too fast. Now return to behaviour editing to fix this issue.

Set a Cool down Time for Flipper

1. Return to the "flipper left" object's "Rotate" action. First, we add a "Set Rotation" block and after the last "Rotate" block and set Time to 0, then add a "Vector3" to set its Target. This will instantly set the flipper back to its original rotation. Then add a "Wait For" block after the "Set Rotation" block, and set the Time to 0.1. When this action is called, the rotation of the left flipper will reset to 0 after it rotates back and wait for 0.1s to cool down.

2. We then break the connection between the "Action Start" block and the "Rotate" block by dragging and releasing the "Action Start" block's out flow node, the connection wire will disappear. Then append a "Branch" block to the "Action Start" block followed by a "Set Boolean" block linked to the False node of the "Branch" block, then connect the "Set Boolean" block back to the original "Rotate" block. For the Branch block's Condition, we retrieve the "flipper left" object's "rotate" variable state. Then in the "Set Boolean" block, we set the "flipper left" object's "rotate" variable to True. Lastly, after the "Wait For" block, we again set the "flipper left" object's "rotate" variable to False using a "Set Boolean" block. By modifying the "Rotate" action this way, the left flipper will only start to rotate when the flipper is not currently in rotating motion, and it will wait for 0.1 seconds after it's able to be called to rotate again.

3. Enter play mode and test the newly modified rotate behaviour and observe the subtle difference.

4. Now you can repeat the whole procedure on the right flipper object. First create the "Rotate" action on the right flipper.

5. Back to the left flipper and select the whole behaviour flow, copy them and paste them to the flipper right object's "Rotate" action.

6. On the right flipper's behaviour panel, open the "Show Item Variables" and add a new variable named "rotate", set the variable type to "Boolean" and set its default value to False.

7. After pasting the behaviour flow, change all Target to "flipper right" and reverse the Z values in the "Vector3" blocks.

8. Open the Flipper Left object's behaviour panel. Break the connection between the "Action Start" and "Branch" block and add a "Parallel" block between them. Connect one of "Parallel" block's out flow node with the "Branch" block and add a new "Call Action" block behind the other node. Finally, set the "Target Action" of the "Call Action" block to "flipper right.fbx : Rotate". When this action is called, both sides of the flippers will rotate simultaneously.

Create Behaviour to the Ball when it Touches the Flippers

1. From the "Ball" object's behaviour panel. Select the behaviour flow outlined below, then duplicate it 2 more times on the canvas.

2. For the first duplicated "Start Contact" block, set the Target to "flipper left.fbx" and change the X and Y Value of the "Vector3" blocks to 1 and 5 respectively. Repeat the process for the other duplicated "Start Contact" block, this time set the Target to "flipper right.fbx" and change the X and Y Value to -1 and 5.

3. Next, we will add a condition to the flipper object's "Start Contact" behaviour flow, so the "Add Force" is only applied to the ball if the flipper is rotating. To do so, insert a "Branch" block between the "Start Contact" and the "Add Force" block. We set a Condition to check the "flipper left" object's "rotate" variable, and only proceed to "Add Force" if "rotate" is True. With the "Ball" object is selected then open its behaviour panel. Remember to set "Relative" to false in "Add Force" block. Repeat the same procedure for the right flipper. When this action is called, force will only be added when the flippers are rotating.

4. Now, enter the play mode and test the behaviour. The flippers should rotate together when you click the "Rotate" button. When the ball hits the rotating flippers, it should bounce off with an added force.

Create the Counting System

In this section, you will learn how to implement a scoring system for your pinball game. You will set up score tracking using variables, created score display functionality, and implemented score incrementing when the ball hits various game elements like bumpers and slingshots. You will also added score reset functionality when the ball falling through the bottom.

1. Open the Ball object's behaviour panel and add a new variable named "Count", set the variable type to "Number" and default value to 0.

2. Select the Score object and open its behaviour panel. Under "Groups", create a new action name "UpdateScore". An "Action Start" event trigger block will appear on the canvas.

3. Switch to behaviour Library, append a "Set Text" block to the "Action Start" block. Use a "Get Number" block to retrieve the "ball" object's "Count" variable value, then use a "Number To Text" block to convert the number to Text format for display by the "Set Text" block. When this action is called, the score will be updated.

4. We want to give some score to the player if the ball hits the bumpers and slingshots in the playfield. Using the left bumper as an example, open its behaviour panel and add a "Start Contact" block onto the canvas, set the Target to "Ball". Then add a "Set Number" block to update the score. To do so, use a "Get Number" block to retrieve the current score on the "Ball" object's "Count" variable then use an "Add" block to increment the score by 1. Finally, add a "Call Action" block and set its "Target Action" to the "Score" object's "UpdateScore" action, so the updated score will be displayed.

5. Copy this behaviour flow and paste it to the other Bumpers and Slingshots canvas.

6. Lastly, we want to reset the score to 0 when the ball hits the Trough. Open the Ball object's behaviour panel, add a "Set Number" block behind the "Set Position" block and use it to set the "Count" variable on the "Ball" object to 0. Then switch to the "Flow Control" category, drag and drop the "Call Action" block and set its "Target Action" to the "Score" object's "UpdateScore" action. When the ball contacts the Trough, the score will be reset to 0.

7. Finally, press the "Play" button and test the counting system by pressing the "Shoot" button to shoot the ball and deflecting the ball with the flippers by pressing the "Rotate" button. Notice that if the ball makes contact with bumpers or slingshots, the score text should increase by one.