add pybullet file to track VR controller attached to some robot (such as minitaur)

press button to toggle tracking, other button to reset orientation of controller, relative to robot.

examples/pybullet/vrminitaur.py

@@ -0,0 +1,49 @@
+#script to track a robot with a VR controller attached to it.
+
+import time
+import pybullet as p
+
+#first try to connect to shared memory (VR), if it fails use local GUI
+c = p.connect(p.SHARED_MEMORY)
+if (c<0):
+	c = p.connect(p.GUI)
+p.resetSimulation()
+p.setGravity(0,0,0)
+print(c)
+if (c<0):
+		p.connect(p.GUI)
+		
+#load the MuJoCo MJCF hand
+minitaur = p.loadURDF("quadruped/minitaur.urdf")
+robot_cid = -1
+
+POSITION=1
+ORIENTATION=2
+BUTTONS=6
+
+p.setRealTimeSimulation(1)
+
+controllerId = -1
+
+while True:
+	events = p.getVREvents()
+	for e in (events):
+		#print (e[BUTTONS])
+		if (e[BUTTONS][33]&p.VR_BUTTON_WAS_TRIGGERED ):
+			if (controllerId >= 0):
+				controllerId = -1
+			else:
+				controllerId = e[0]
+		if (e[0] == controllerId):
+			if (robot_cid>=0):
+				p.changeConstraint(robot_cid,e[POSITION],e[ORIENTATION], maxForce=5000)
+		if (e[BUTTONS][32]&p.VR_BUTTON_WAS_TRIGGERED ):
+			if (robot_cid>=0):
+				p.removeConstraint(robot_cid)
+
+			#q = [0,0,0,1]
+			euler = p.getEulerFromQuaternion(e[ORIENTATION])
+			q = p.getQuaternionFromEuler([euler[0],euler[1],0]) #-euler[0],-euler[1],-euler[2]])
+			robot_cid = p.createConstraint(minitaur,-1,-1,-1,p.JOINT_FIXED,[0,0,0],[0.1,0,0],e[POSITION],q,e[ORIENTATION])
+
+