add example of a free moving sphere controlled by external torque

add some toy shape sorter cube (not finished yet)

examples/pybullet/examples/externalTorqueControlledSphere.py

@@ -0,0 +1,61 @@
+import pybullet as p
+import pybullet_data
+import time
+
+p.connect(p.GUI)
+p.setAdditionalSearchPath(pybullet_data.getDataPath())
+p.loadSDF("stadium.sdf")
+p.setGravity(0,0,-10)
+objects = p.loadMJCF("mjcf/sphere.xml")
+sphere = objects[0]
+p.resetBasePositionAndOrientation(sphere,[0,0,1],[0,0,0,1])
+p.changeDynamics(sphere,-1,linearDamping=0.9)
+p.changeVisualShape(sphere,-1,rgbaColor=[1,0,0,1])
+forward = 0
+turn = 0
+
+
+forwardVec = [2,0,0]
+cameraDistance = 1
+cameraYaw = 35
+cameraPitch = -35
+
+while (1):
+
+	spherePos, orn = p.getBasePositionAndOrientation(sphere)
+	
+	cameraTargetPosition = spherePos
+	p.resetDebugVisualizerCamera(cameraDistance,cameraYaw,cameraPitch,cameraTargetPosition)
+	camInfo = p.getDebugVisualizerCamera()
+	camForward = camInfo[5]
+	
+	
+	keys = p.getKeyboardEvents()
+	for k,v in keys.items():
+		
+		if (k == p.B3G_RIGHT_ARROW and (v&p.KEY_WAS_TRIGGERED)):
+			turn = -0.5
+		if (k == p.B3G_RIGHT_ARROW and (v&p.KEY_WAS_RELEASED)):
+			turn = 0
+		if (k == p.B3G_LEFT_ARROW and (v&p.KEY_WAS_TRIGGERED)):
+			turn = 0.5
+		if (k == p.B3G_LEFT_ARROW and (v&p.KEY_WAS_RELEASED)):
+			turn = 0
+		
+		if (k == p.B3G_UP_ARROW and (v&p.KEY_WAS_TRIGGERED)):
+			forward=1
+		if (k == p.B3G_UP_ARROW and (v&p.KEY_WAS_RELEASED)):
+			forward=0
+		if (k == p.B3G_DOWN_ARROW and (v&p.KEY_WAS_TRIGGERED)):
+			forward=-1
+		if (k == p.B3G_DOWN_ARROW and (v&p.KEY_WAS_RELEASED)):
+			forward=0
+	
+	force  = [forward*camForward[0],forward*camForward[1],0]
+	cameraYaw = cameraYaw+turn
+	
+	if (forward):
+		p.applyExternalForce(sphere,-1, force , spherePos, flags = p.WORLD_FRAME )
+		
+	p.stepSimulation()
+	time.sleep(1./240.)