writing joystick position to a data file

[Saz]

Hi there,

I'm after creating data files for each of my subjects that gives me the position of the joystick as they are driving down my virtual road. I have the following code:

import viz
#Import vizjoy module
import vizjoy  
import time
import math
viz.go(viz.FULLSCREEN)
viz.mouse(viz.OFF)


subject = viz.input('What is the participant number?')

#define speed
MOVE_SPEED = 0.5 #scalar constant for speed gain

#Add a joystick 
joy = vizjoy.add() 

viz.clearcolor(0.5,0.5,1)
viz.MainView.setPosition(0,.5,0)

sky = viz.add(viz.ENVIRONMENT_MAP,'sky.jpg')

skybox = viz.add('skydome.dlc')
skybox.texture(sky)

#there are two road textures with different line count in the middle
#road = viz.add('road.jpg')
road = viz.add('roadld.jpg')
#road2 = viz.add('road2.jpg')


#add the ground
ground = viz.add('tut_ground.wrl')
ground.setPosition(0,0,25)

#create a texture quad to add the road texture to
#and place it over ground
quad = viz.addTexQuad()
quad.setScale(1,2,1)
quad.setPosition(0,.1,0)
quad.setEuler(0,90,0)
quad.texture(road)

road_position = 0
ground_position = 50
#add road and ground if getting near the end of road
def addRoad():
	
	global road_position, ground_position
	
	viewpoint_pos = viz.MainView.getPosition()
	#check to see how close the viewpoint is to the end of the road
	if road_position - viewpoint_pos[2] < 50:
		
		#add 50 meters of ground
		global ground_position
		groundcopy = ground.copy()
		groundcopy.setPosition([0,0,ground_position])
		ground_position +=50
		
		#add 50 meters of road
		for i in range(1,50):
			quadcopy = quad.copy()
			quadcopy.setPosition([0,.1,road_position])
			quadcopy.setEuler(0,90,0)
			road_position +=1

addRoad()
#call a timer every frame to check if road needs to be added
vizact.ontimer(0, addRoad)

#change the road texture on keypress
#vizact.onkeydown('1', quad.texture,road2)
#vizact.onkeydown('2', quad.texture,road)
vizact.onmousedown(viz.MOUSEBUTTON_LEFT, quad.texture,road)
#vizact.onmousedown(viz.MOUSEBUTTON_LEFT, quad.texture,road2)

def UpdateJoystick():
    #Get the joystick position
    x,y,z = joy.getPosition()
    #Get the twist of the joystick
    twist = joy.getTwist()
    #Move the viewpoint forward/backward based on y-axis value
    if abs(y) > 0.001: #Make sure value is above a certain threshold
        viz.MainView.move(0,0,-y*MOVE_SPEED,viz.BODY_ORI)
    #Move the viewpoint left/right based on x-axis value
    if abs(x) > 0.001: #Make sure value is above a certain threshold
        viz.MainView.move(x*0.1,0,0,viz.BODY_ORI)
    #Turn the viewpoint left/right based on twist value
    if abs(twist) > 0.001: #Make sure value is above a certain threshold
        viz.MainView.rotate(0,1,0,twist,viz.BODY_ORI,viz.RELATIVE_WORLD)


#UpdateJoystick every frame
vizact.ontimer(0,UpdateJoystick)

def mytimer( num ):
  print joy.getPosition()
viz.callback( viz.TIMER_EVENT, mytimer )
viz.starttimer( 0, 0.5, viz.FOREVER ) 


#write out to a file
start_time = time.time()
speed_data = open('speed_' + str(subject),'w')
# Define a function that saves data
# Define a function that saves data
def SaveData(currenttime, key):
    # Create the output string
    out = str(currenttime) + '\t' + key + '\n'               
    # Write the string to the output file
    file.write(out)                                     
    # Makes sure the file data is really written to the harddrive
    file.flush()                                        
    print out
   
# Define a function that is called every time a keyboard button is pressed
def mykeyboard(key):          
    # Calls the function SaveData and hands it the current time and key
    SaveData(viz.tick(),key)

# Defines a callback for keyboard events
viz.callback(viz.KEYBOARD_EVENT, mykeyboard)

but obviously the "key" coding for the SaveData and "mykeyboard" part is not going to work but I can't find out the equivalent code to insert for the joystick position. It outputs the joystick position to the screen ok so I just want it to write to a file

Any advice is greatly appreciated!

[Jeff]

You can get the joystick position and convert it to a string and output that to the file

joy_pos = str(joy.getPosition())
# Create the output string
out = str('current position' + '\t' + joy_pos + '\n')
# Write the string to the output file
file.write(out)                                     
# Makes sure the file data is really written to the harddrive
file.flush()

[Saz]

That's brilliant thanks for that Jeff, but when I run it and open the file, there is no output recorded at all. Would I have to incorporate a timer loop/callback event as well?

[Saz]

No worries Jeff - I've now worked out how to do it