Public Member Functions
def	__init__
def	down
def	drag
def	getconstrain
def	matrix
def	next
def	place
def	setaxes
def	setconstrain
Private Attributes
	_axes
	_axis
	_center
	_constrain
	_qdown
	_qnow
	_qpre
	_radius
	_vdown

Detailed Description

Virtual Trackball Control.

>>> ball = Arcball()
>>> ball = Arcball(initial=numpy.identity(4))
>>> ball.place([320, 320], 320)
>>> ball.down([500, 250])
>>> ball.drag([475, 275])
>>> R = ball.matrix()
>>> numpy.allclose(numpy.sum(R), 3.90583455)
True
>>> ball = Arcball(initial=[1, 0, 0, 0])
>>> ball.place([320, 320], 320)
>>> ball.setaxes([1, 1, 0], [-1, 1, 0])
>>> ball.setconstrain(True)
>>> ball.down([400, 200])
>>> ball.drag([200, 400])
>>> R = ball.matrix()
>>> numpy.allclose(numpy.sum(R), 0.2055924)
True
>>> ball.next()

Definition at line 1496 of file transformations.py.

Constructor & Destructor Documentation

def semanticmodel.transformations.Arcball.__init__	(	self,
		initial = `None`
	)

Initialize virtual trackball control.

initial : quaternion or rotation matrix

Definition at line 1520 of file transformations.py.

Member Function Documentation

def semanticmodel.transformations.Arcball.down	(	self,
		point
	)

Set initial cursor window coordinates and pick constrain-axis.

Definition at line 1573 of file transformations.py.

def semanticmodel.transformations.Arcball.drag	(	self,
		point
	)

Update current cursor window coordinates.

Definition at line 1583 of file transformations.py.

def semanticmodel.transformations.Arcball.getconstrain ( self )

Return state of constrain to axis mode.

Definition at line 1569 of file transformations.py.

def semanticmodel.transformations.Arcball.matrix ( self )

Return homogeneous rotation matrix.

Definition at line 1601 of file transformations.py.

def semanticmodel.transformations.Arcball.next	(	self,
		acceleration = `0.0`
	)

Continue rotation in direction of last drag.

Definition at line 1596 of file transformations.py.

def semanticmodel.transformations.Arcball.place	(	self,
		center,
		radius
	)

Place Arcball, e.g. when window size changes.

center : sequence[2]
    Window coordinates of trackball center.
radius : float
    Radius of trackball in window coordinates.

Definition at line 1545 of file transformations.py.