VR Input System

The VR input system allows managing user input from VR controllers, head-mounted displays (HMDs), base stations, and trackers. It supports a wide range of VR devices, enabling you to utilize several devices from various vendors and process input from them.

The InputVRDevice class provides access to properties and settings common for all VR devices (for example, a device name).

Controllers serve as a primary interface for VR input. There are three types of VR controllers: left-hand, right-hand controllers, and a treadmill. You can get the controller's type and check whether it is a hand controller by using the corresponding methods of the InputVRController class.

The VR input system supports a range of controller models compatible with OpenVR, Varjo, and OpenXR devices. In this article, we will consider the following:

• General approach to processing inputs on VR controllers.
• Examples of inputs on some models of OpenVR-compatible devices (HTC Vive, Oculus Touch, and Valve Knuckles).

UNIGINE API provides access to the VR controller inputs — axes and buttons.

• Buttons are mapped to the controller's buttons that can be pressed, touched, or released.
• Axes detect 1-dimensional movement of the control and have more complex behavior.

  Depending on the type of the VR controller, the number of axes differs. UNIGINE supports several axes. But usually, a controller has 3 or 4.

  In UNIGINE, an axis can be mapped to a control of one of the supported types, also referred to as an axis type.

  Notice

  You cannot know in advance which type of controller is connected, so UNIGINE API allows you to identify the number of supported axes, check their types, find the axis index by its type via findAxisByType(), or get a state value for the axis via getAxisByType().

General Approach to VR Controller Inputs#

bool isTeleportButtonPressed(InputVRControllerPtr device)
{
	if (!device || device->isAvailable() == false || device->isTransformValid() == false)
		return false;

	// check if there is the X button on the controller
	if (device->getSupportedButtonsMask() & (1ull << uint64_t(Input::VR_BUTTON_X)))
		// consider the X button as the teleport button and check if it is pressed
		return device->isButtonPressed(Input::VR_BUTTON_X);

	// if there is no X button on the controller, try to use the Trackpad, Trigger, or Grip button as the teleport button 
	VectorStack<InputVRController::AXIS_TYPE> axis_types = { InputVRController::AXIS_TYPE_TRACKPAD_X, InputVRController::AXIS_TYPE_TRIGGER_VALUE, InputVRController::AXIS_TYPE_GRIP_VALUE };
	for (int i = 0; i < axis_types.size(); i++)
	{
		// find the axis index by the axis type
		int axis_index = device->findAxisByType(axis_types[i]);
		if (axis_index == -1)
			continue;

		Input::VR_BUTTON button = Input::VR_BUTTON(Input::VR_BUTTON_AXIS_0 + axis_index);
		if (device->getSupportedButtonsMask() & (1ull << uint64_t(button)))
			return device->isButtonPressed(button);
	}

	return false;
}

Inputs for OpenVR Controllers#

The VR system allows you to process input from head-mounted displays (HMDs) via the InputVRHead class.

A VR base station helps the HMD and controllers to track their exact positions, enhancing the immersion of room-scale virtual reality experience.

The InputVRDevice and InputVRBaseStation classes is used to handle base station input.

A VR tracker allows embedding real-world objects into the VR environment. You can attach it to a real thing that needs to be tracked. In Mixed Reality, you can install the VR tracker on a camera or player to track its position in the virtual world.

The InputVRDevice and InputVRTracker classes is used to manage tracker input.