Mixed Reality Racer is a driving game where you utilize Occipital’s Bridge to scan a real world environment and then race through it, with a mixed reality, remote control car. Race the clock to hit as many checkpoints as possible before the time runs out!

• iPhone 6S, 7 with iOS 9.3+
• Unity 2017.2+ with iOS, VR support.
• Occipital Structure Sensor
• Ocipital Bridge Headset compatible with the iPhone generation in possession
• Ocipital's Bridge Remote Control.

We attempt to keep our work separated from the imported packages. Within our work folder, we separate raw assets created by the artists from implemented features. The structure diagram is as follow:

In CarControllerInput base class, the TriggerGroundImpactEffect, TriggerWallImpactEffect, and TriggerGameOverBoomEffect coroutines handle the special effects.

• TriggerGroundImpactEffect is triggered when the car land on the floor from a jump, referenced by OnCollisionEnter

• TriggerWallImpactEffect is triggered when the car hits a wall. A collision is a wall hit if the difference between the collision.contacts[0].normal and Vector3.up is less than 10f. referenced by OnCollisionEnter. We created three wall impact prefabs, so this coroutine randomlly choose an effect on collision.

• TriggerGameOverBoomEffect is triggered when the game runs out of time. it launches the driver ejected animation. This coroutine is referenced by GameOverState class OnStateEnter method.

The effects are stored in Assets/Team_XR/Sean_VFX, and are prefabs in the CarControllerInput base class.

The car also has engine smoke attached to it. The prefab is located in TeamXR/Thatlita's Particle.

The car engine is a Unity standard vehicle asset and originally uses CrossPlatformInput for inputs. We modified the input method to fit for the Bridge headset remote control.

We used the low poly stylized car, replacing our desired mesh and customized certain fields of the Assets/StandardAssets/Vehicles/Car/Scripts/CarController, mainly resizing WheelColliders.

We used an existing asset in Unity store character pack for our car and driver. A driver animator is attached to the driver prefab. the various states are activated by isDriverEjected and isPlayCheckpointAnimation boolean.

Chillling - this is the main state, driver is just driving.

DriverEjected - this state is triggered by the above TriggerGameOverBoomEffect

DriverHitCheckpoint - this state launches a celebratory fist animation when the car hits a checkpoint.

The CarControllerInput contains a CarMotionData object which has 2 fields: steering and motorTorque. The car's movement is updated by the FixedUpdate method.

The CarControllerInput is subscribed to BridgeEngineUnity following events: OnMotionEvent(Vector3 position, Quaternion rotation) - Thrown when the remote control is moved. `OnButtonEvent(int current, int down, in up) - Update status of each button, each button takes a bit in the integer (0 - off, 1 - on)

[Flags]
public enum BEControllerButtons : int {
    ButtonPrimary   = 1<<0, // Trigger pulled or CODAWheel clicker
    ButtonSecondary = 1<<1, // App button with (•••)
    ButtonHomePower = 1<<2, // Home/Power button with (o)
    ButtonTouchpad     = 1<<3, // Touch pad clicker pressed
    ButtonTouchContact = 1<<4, // Touch pad contact with finger
}

OnTouchEvent (Vector2 position, BEButtonStatus touchStatus) Update when the player's finger is on the touchpad, the parameter position of the touch, each axis component is ranged from [-1,1]. The parameter touchStatus` returns the status of the touch:

public enum BEControllerTouchStatus : int {
    TouchIdle = 0,
    TouchFirstContact = 1,
    TouchReleaseContact = 2,
    TouchMove = 3
}

We have three controller styles available.

ControllerInputA -uses DPAD for steering. Acceleration and braking is based on where you are pressing on DPAD relative to the center, hold the secondary buttons to reset

ControllerInputB -uses the rotation around axis Z of the controller for steering, primary button for acceleration, secondary button for braking, hold both primary + secondary buttons to reset

ControllerInputC - uses the DPAD for steering, primary button for acceleration, and secondary button for braking. hold both primary + secondary buttons to reset

The default is ControllerInputA, to switch controllers, remove the current controllerInput script from the car, and swap in the desired controller, the controllers are stored in Assets/Team_XR/Car/Scripts

The app is controlled by GameManager object. It has an Unity AnimatorController attached to it to control its states. The controller directory is: Assets/TeamXR/Game/GameStateMachine.controller

Each state is derived from Unity StateMachineBehavior. We overrided the 3 overridable functions of the class:OnStateEnter, OnStateUpdate. OnStateExit. Each main state class can have its own derived class for each substate.

The main States are as follow:

Each Main state has its own substates to handle different behaviors within that states. The state are changed based on the condition set for each inter-state transition. To trigger a transition, set certain parameter of the controller of the animator to the value that matches the set condition.

Currently, main state transition is activated by integer parameter State while substate is activated mainly using trigger NextSubState.

The car's RigidBody Component is set to isKinematic, turning off all physical interaction and the player cannot move the car. An UI Popup is shown to instruct player how to play the game.

Big countdown text is shown as the player prepares themselves to enter the game.

Controls the game component of the app.

Turns on visual UI for TimeRemaining and CheckpointCount. Future behaviors including animations right before the game starts can be added here. Proceeds to GamePlayingState immediately.

The car's physic is on and the player can control the car. The UI showing RemainingTime and CheckpointCount to show the player's progress. Proceeds to GameOverState once the game is over.

Car's physic is disabled, a text says "GameOver". After a few seconds, proceed to ResultState.

UI Popup is shown displaying the number of checkpoint reached during the last game. Proceeds to CountdownState state once the user press the Trigger button.

Since collecting checkpoints can get boring, there are obstacles to increase the stake of the game. Current obstacles implemented include:

Player can extend their game time by reaching the assigned checkpoint before the countdown. The time awarded is based on the distance between the current and previous checkpoints. This is not completely balanced and can be edited in Game.TimeAllowanceSettings

Files related to checkpoint is in Asset/TeamXR/Checkpoint

Tornado randomly pick a m_TargetPosition to traverse towards, once the target is reached, it will be updated to a new position. The value is determined using CustomRaycasting.RayCastToScene().

Tornado has a Collider acting as a Trigger that rapidly reduces the remaining time of the game upon contact with player's car.

Currently, it is difficult to view the UI in VR mode due to the distortion of the Stereoscopic view. The timer and the checkpoint count is difficult to spot and pay attention to according to the user feedback.

This is because of the vehicle's physic implementation using Unity WheelColliders. This results in the car possibly stuck where it is impassible for regular vehicle without external force. To remedy this, the player can activate a reset sequence on the controller to be randomly spawned somewhere else.

We discovered it was a multi-thread issue involving the OnCollisionEnter being called multiple times (3 times) in one frame, we set a boolean value called isReadyEffect but it is not being utilized as intended.

The checkpoint moves to a new location upon contact with the player. Since the transition is linear, the checkpoint will be clipped if the height of certain terrain polygon is higher than the checkpoint.

Possible solutions include:

• Create a new Material applied to the checkpoint that uses a shader that always renders the checkpoint on top the terrain mesh.
• Use CustomRaycast.RaycastToScene() to determine the position of the checkpoint each frame as it moves.

• Samantha Yueh - Project Manager, Scrum Master, UI/UX Designer

• Seán Conroy - Creative Lead

• Nick Kubash - Art Style Lead, 3D Artist

• Viet Phan - Programming Lead

• Andy Yao - Programmer

• Thalita Karina - 3D Motion Designer

• Manni Zhang - 3D Artist

• Aaron Hilton at https://steampunk.digital/
• Jacob Ervin at https://occipital.com/