rotating an object

[Penguin]

Step by step I'm able to locate the source of the problem: I use the sphere in a hierarchical group order. The following code reproduces the strange behaviour of rotating.

import viz
import vizmat
import vizshape

viz.go()
viz.mouse.setOverride(viz.ON)

root = viz.add(viz.GROUP, parent=viz.WORLD)
root.setPosition([0,1.8,3],viz.REL_GLOBAL)

node = vizshape.addSphere(pos=[0,0,0], parent=root)
node.texture(viz.add('image2.jpg'))
rotation = None
def onGrab():
	global rotation
	intersectionItem = viz.pick(1)
	if intersectionItem.valid:
		src_ori = vizmat.Quat(node.getQuat(viz.ABS_GLOBAL))
		node.lookat(intersectionItem.point, viz.ABS_GLOBAL)
		dst_ori = vizmat.Quat(node.getQuat(viz.ABS_GLOBAL))
		#D = O * S so O = D * 1/S
		rotation =  src_ori * dst_ori.inverse()
		
vizact.onmousedown(viz.MOUSEBUTTON_LEFT, onGrab)

def moveSphere():
	if rotation:
		intersectionItem = viz.pick(1)
		if intersectionItem.valid:
			node.lookat(intersectionItem.point)
			node.setQuat(rotation, viz.ABS_LOCAL)
			
vizact.onupdate(viz.PRIORITY_DEFAULT, moveSphere)
		
def endGrab():
	global rotation
	rotation = None
vizact.onmouseup(viz.MOUSEBUTTON_LEFT, endGrab)

[Jerry]

Here's another way to do it.

from viz import *

go()

clearcolor(.8,.8,.8)
vert = add('ball.wrl')
vert.translate(0,1.8,2)

xang = 0
yang = 0
INCREMENT = .5

mouse(OFF)
restrictmouse(OFF)

def mousemove(x,y):					
	global xang,yang
	
	state = buttonstate()

	if state == MOUSEBUTTON_LEFT:
		xang = xang + x*INCREMENT
		yang = yang + y*INCREMENT
		vert.rotate(0,1,0,-x*INCREMENT,RELATIVE_WORLD)
		vert.rotate(1,0,0,y*INCREMENT,RELATIVE_WORLD)
		
mousedata(RELATIVE,RELATIVE)
callback(MOUSEMOVE_EVENT,mousemove)

[Gladsomebeast]

Interesting... I shall dub thee Spinner Metaphor Method and place you in a file of honor.

[Penguin]

Hi Gladsomebeast, the effect of slight roll results in the lookat call. The second argument is a optional roll value. The internal value of viz.ABS_GLOBAL is 4:

node.lookat(intersectionItem.point, 0, viz.ABS_GLOBAL)

not

node.lookat(intersectionItem.point,viz.ABS_GLOBAL)

because this is a roll of 4 degree

node.lookat(intersectionItem.point,4)