void GpGpuApp::mouseDown( MouseEvent event )
{
	if ( event.isControlDown() ) {
		mArcball.mouseDown( event.getPos() );
	} else {
		mMouseVelocity	= Vec2f::zero();
		mMouse			= Vec2f( event.getPos() );
		mMouseDown		= true;
	}
}
void PaintingBeingsApp::mouseDown(MouseEvent event)
{
	_arcball.mouseDown(event.getPos());
}
void VboMeshSampleApp::mouseDown( MouseEvent event )
{
	// Rotate with arcball
	mArcball.mouseDown( event.getPos() );
}