import viz
import vizinfo
import vizact

viz.setMultiSample(4)
viz.fov(60)
viz.go()

vizinfo.add('This script demonstrates how to use animation paths\nThe 4 transparent balls represent the control points\nThe rest of the animation is done by Vizard\nUse the on screen buttons to change certain options')

#Add the ground plane
ground = viz.addChild('ground.osgb')

#Add the ball to animate
ball = viz.addChild('beachball.osgb')

#Move the viewpoint back
viz.MainView.move([0,0,-7])

#Create the animation path
path = viz.addAnimationPath()

#Initialize an array of control points
positions = [ [0,0,2], [2,0,0], [0,0,-2], [-2,0,0] ]

for x,pos in enumerate(positions):
    #Add a ball at each control point and make it
    #semi-transparent, so the user can see where the
    #control points are
    b = viz.addChild('beachball.osgb',cache=viz.CACHE_CLONE)
    b.setPosition(pos)
    b.alpha(0.2)
    #Add the control point to the animation path
    #at the new time
    cp = viz.addControlPoint()
    cp.setPosition(pos)
    path.add(cp,x+1)

#Set the initial loop mode to circular
path.loop(viz.CIRCULAR)

#Automatically compute tangent vectors for cubic bezier translations
path.computeTangents()

#Automatically rotate the path
path.setAutoRotate(viz.ON)

#Link the ball to the path
viz.link(path, ball)

#Play the animation path
path.play()

def changeSpeed(pos):
    #Adjust the speed of the animation path
    path.speed(pos*10)

#Setup callbacks for slider events
vizact.onslider(speed, changeSpeed)

#Setup button click events
vizact.onbuttondown(no_loop,path.loop,viz.OFF)
vizact.onbuttondown(loop,path.loop,viz.LOOP)
vizact.onbuttondown(swing,path.loop,viz.SWING)
vizact.onbuttondown(circular,path.loop,viz.CIRCULAR)
vizact.onbuttondown(linear,path.setTranslateMode,viz.LINEAR_INTERP)
vizact.onbuttondown(bezier,path.setTranslateMode,viz.BEZIER)
vizact.onbuttondown(cubic,path.setTranslateMode,viz.CUBIC_BEZIER)