无限循环背景ParallaxNode

void  ParallaxNode::incrementoffset(Point offset, Node*  node)
{
for (unsigned int i = 0; i < _parallaxArray->num; ++i)
{
PointObject*  point = (PointObject*)_parallaxArray->arr[i];
Node*  curNode = point->getChild();
if (curNode == node)
{
point->setOffset(point->getOffset()+ offset);
}
}
}

function InfiniteBg:update(dt)
for k,bg in pairs(self.bgs) do
local p = cc.p(bg:getPosition())
local width = bg:getContentSize().width;
p = self:convertToWorldSpace(p)
if (p.x < -width) then
print("[InfiniteBg] : repeat bg")
self:incrementoffset(cc.p(width,0),bg);
end
end
end