[ssaha]

I have been trying to use UserAvatar.py for navigation from link:
http://vizworkshop.com/articles/walkthrough_app

I did two following changes in UserAvatar file:

Change 1: In _init_ function, I used collideBox in place of collideCapsule.

Change 2: In updatePrePhysics, I changed headEuler following way:

headEuler = self.head.getEuler(viz.ABS_GLOBAL)
headEuler[0] = headEuler[0] + yawChange
headEuler[1] = headEuler[1]
headEuler[2] = headEuler[2]
self.head.setEuler(headEuler, viz.ABS_GLOBAL)


Problem: In code, there is no change of y-coordinate of self.feet. According to code, it should be
always zero (0). But when I run the code with above change, I get change in y-coordinate of self.feet. So in order to keep it zero, I add following code in updatePostPhysics:

temp_pos= self.feet.getPosition(viz.ABS_GLOBAL)
temp_pos[1]=0
self.feet.setPosition(temp_pos)


After doing this , y is zero . But movement is not smooth.


Could you give any solution? For your convenience, updated UserAvatar.py is attached below.

'''
Moves the view according to user input
'''	

import viz
import vizact
import vizmat
import viztask

class UserAvatar(viz.EventClass):
	THROTTLE_SPEED = 4
	HYPER_THROTTLE_SPEED = 30
	TURN_SPEED = .1
	def __init__(self):
		viz.EventClass.__init__(self)
		self.feet = viz.addGroup(pos=[0, 0, 0]) #position of user avatar
		
		#physics init
		self.physicShape = self.feet.collideBox([0.5,1,0.5],friction=.00000001, hardness=.0000001, bounce=0)
		self.velMotor = self.feet.addVelocity(velocity=[0,0,0], maxForce=100, gravity=False))		
		#orientation of user avatar
		self.head = viz.addGroup()
		#view should link to this
		self.avatar = viz.mergeLinkable(self.feet, self.head)
		
		self.mouseDx = 0
		self.mouseDy = 0
		self.callback(viz.MOUSE_MOVE_EVENT, self.onMouseMove)
		
		vizact.onupdate(viz.PRIORITY_PHYSICS-1, self.updatePrePhysics)
		vizact.onupdate(viz.PRIORITY_PHYSICS+1, self.updatePostPhysics)
		
	def updatePrePhysics(self):
		throttle = vizmat.Vector([0,0,0])
		## Steer Control
		yawChange = self.mouseDx * self.TURN_SPEED
		pitchChange = -self.mouseDy * self.TURN_SPEED			
		#discard old mouse movement and start collecting new mouse input
		self.mouseDx = 0
		self.mouseDy = 0
		
		headEuler = self.head.getEuler(viz.ABS_GLOBAL)
		headEuler[0] = headEuler[0] + yawChange
		headEuler[1] = headEuler[1]
		headEuler[2] = headEuler[2]
		self.head.setEuler(headEuler, viz.ABS_GLOBAL)
			
		## Translate Control
		throttle.set([0,0,0])
		#forward/back
		if viz.key.isDown('w') or viz.mouse.getState() & viz.MOUSEBUTTON_LEFT:
			throttle += [0,0,1]
		if viz.key.isDown('s') or viz.mouse.getState() & viz.MOUSEBUTTON_RIGHT:
			throttle += [0,0,-1]
		#left/right
		if viz.key.isDown('a'):
			throttle += [-1,0,0]
		if viz.key.isDown('d'):
			throttle += [1,0,0]
		throttle.normalize() #<--direction
		if viz.key.isDown(' ') or viz.mouse.getState() & viz.MOUSEBUTTON_MIDDLE:
			throttle *= self.HYPER_THROTTLE_SPEED
		else:
			throttle *= self.THROTTLE_SPEED
			
		if throttle.length(): #if throttle not zero
			#move forward in direction of head
			newVel = vizmat.Transform()
			newVel.setTrans(throttle)			
			newVel.postEuler(self.head.getEuler(viz.ABS_GLOBAL))
			self.velMotor.setVelocity(newVel.getTrans())
		else:
			self.velMotor.setVelocity([0, 0, 0])


	def updatePostPhysics(self):
		self.feet.setEuler([0, 0, 0])
		
	def onMouseMove(self, e):
		#fuction called twice, once for movement on x axis, once for y axis
		self.mouseDx = self.mouseDx + e.dx
		self.mouseDy = self.mouseDy + e.dy
	
	def linkView(self, view):
		return viz.link(self.avatar, view, srcFlag=viz.LINK_ABSOLUTE, dstFlag=viz.LINK_POS_RAW)

	def setPosition(self, xyz):
		self.feet.setPosition(xyz)
		
	def setEuler(self, euler):
		self.head.setEuler(euler)

if __name__ == '__main__':
	viz.go()
	viz.move([0, 0, -2])
	viz.phys.enable()
	t = viz.add('tankmaze.wrl')
	t.collideMesh(bounce=0, hardness=1, friction=0)
	user = UserAvatar()
	user.feet.setPosition([0, 0, 0])
	user.linkView(viz.MainView)