rotating an object

[Gladsomebeast]

Interesting goal. I whipped up a bit of code that orbits the sphere by telling the sphere to "lookat" the intersection point, then rotating the sphere the initial offset amount.

The code is not quite right yet because sustained clicking on the same point rolls the sphere around that point. Maybe somebody knows whats wrong?

import viz
import vizmat
import vizshape

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

node = vizshape.addSphere(pos=[0, 1.8, 3])
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)

[Penguin]

Except for the slight roll, your code works fine. But here it comes: when I attach the sphere to the main view the rotation doesn't work any longer.

import viz
import vizmat
import vizshape

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

node = vizshape.addSphere(pos=[0, 1.8, 3])
node.texture(viz.add('image2.jpg'))

viewLink = viz.link(viz.MainView,node)
viewLink.preTrans([0,0,3])

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)

[Gladsomebeast]

Righto. The link is overriding the rotation we are giving the sphere. To fix we tell the link to only operate on position

viewLink = viz.link(viz.MainView,node, mask=viz.LINK_POS)

[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)