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Panda3D Manual: VR Helmets and Trackers


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This section is especially geared towards Carnegie Mellon University's virtual reality equipment. The tracking setup used consists of a magnetic tracker base that receives signals, a virtual reality headmount, and four small trackers, one of which is attached to the headmount. These magnetic trackers may be held in the hand or implanted in non-metallic objects, and they will relay their position and orientation to the tracker base, which then supplies it to the program.

First, make sure that the VRHandler is in the same folder as your python files. Then, import it as you would any Panda3D module.

from VRHandler import *

Once imported, the VRHandler functions are now available. Make a constant in your code that controls whether or not the tracker is used.

USE_TRACKER = True

or

USE_TRACKER = False

Then, activate the tracker if required:

if USE_TRACKER:
  self.tracker = Tracker()
  camera.reparentTo(self.tracker.getHMDHelper())
else:
  print "Using Mouse and Keyboard Controls"
  self.controls = MouseAndKeyboardControls()
  self.controls.start()

If the tracker is not being used, the above code enables first-person-shooter style controls, using WASD to move, R and F for height, and the mouse to look around. You can add the following lines to your code if you want to customize the feel of the controls:

# Keyboard control constants
self.controls.acceleration = 15
self.controls.maxSpeed = 5
self.controls.friction = 6

Change those three numbers to whatever feels right for your world.

Typically, the tracker base is 6.5 feet off the ground, and the range of the trackers is from three or so inches from the tracker base to around the knees of an average person. The tracker base is treated as a NodePath, so it may be moved around. If you want the guest to move around the world while his real-life feet stay put, get the tracker base helper and move that around:

self.trackerBaseHelper = self.tracker.getTrackerBaseHelper()
self.trackerBaseHelper.setPos(0, 3, 0)

Finally, objects within the Panda3D application may be reparented to the trackers. The four trackers are HMDHelper, YellowHelper, GreenHelper, and BlueHelper. Also, remember that reparenting may create some strange inheritance issues.

NodePath.reparentTo(self.tracker.getHMDHelper() )
NodePath.reparentTo(self.tracker.getYellowHelper() )
NodePath.reparentTo(self.tracker.getGreenHelper() )
NodePath.reparentTo(self.tracker.getBlueHelper() )