function Actor:ease(t, fEase)
	-- Optimizations:
	-- fEase = -100 is equivalent to TweenAccelerate.
	if fEase == -100 then
		self:accelerate(t);
		return;
	end

	-- fEase = 0 is equivalent to TweenLinear.
	if fEase == 0 then
		self:linear(t);
		return;
	end

	-- fEase = +100 is equivalent to TweenDecelerate.
	if fEase == 100 then
		self:decelerate(t);
		return;
	end

	self:tween( t, TweenBezier,
		{
			0,
			scale(fEase, -100, 100, 0/3, 2/3),
			scale(fEase, -100, 100, 1/3, 3/3),
			1
		}
	);
end

local BounceBeginBezier =
{
	0, 0,
	0.42, -0.42,
	2/3, 0.3,
	1, 1
}
function Actor:bouncebegin(t)
	self:tween( t, TweenBezier, BounceBeginBezier );
end

local BounceEndBezier =
{
	0,0,
	1/3, 0.7,
	0.58, 1.42,
	1, 1
}
function Actor:bounceend(t)
	self:tween( t, TweenBezier, BounceEndBezier );
end

local SmoothBezier =
{
	0, 0, 1, 1
}
function Actor:smooth(t)
	self:tween( t, TweenBezier, SmoothBezier );
end

-- Hide if b is true, but don't unhide if b is false.
function Actor:hide_if(b)
	if b then
		self:hidden(1)
	end
end

function ActorFrame:propagatecommand( cmd )
	self:propagate(1);
	self:playcommand(cmd);
	self:propagate(0);
end