-------------------------------------------------------------------------------
-- Spine Runtimes Software License v2.5
--
-- Copyright (c) 2013-2016, Esoteric Software
-- All rights reserved.
--
-- You are granted a perpetual, non-exclusive, non-sublicensable, and
-- non-transferable license to use, install, execute, and perform the Spine
-- Runtimes software and derivative works solely for personal or internal
-- use. Without the written permission of Esoteric Software (see Section 2 of
-- the Spine Software License Agreement), you may not (a) modify, translate,
-- adapt, or develop new applications using the Spine Runtimes or otherwise
-- create derivative works or improvements of the Spine Runtimes or (b) remove,
-- delete, alter, or obscure any trademarks or any copyright, trademark, patent,
-- or other intellectual property or proprietary rights notices on or in the
-- Software, including any copy thereof. Redistributions in binary or source
-- form must include this license and terms.
--
-- THIS SOFTWARE IS PROVIDED BY ESOTERIC SOFTWARE "AS IS" AND ANY EXPRESS OR
-- IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
-- MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
-- EVENT SHALL ESOTERIC SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-- SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
-- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, BUSINESS INTERRUPTION, OR LOSS OF
-- USE, DATA, OR PROFITS) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
-- IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-- POSSIBILITY OF SUCH DAMAGE.
-------------------------------------------------------------------------------

local utils = require "spine-lua.utils"
local interpolation = require "spine-lua.Interpolation"

local setmetatable = setmetatable
local math_min = math.min
local math_max = math.max
local ipairs = ipairs
local table_insert = table.insert
local table_remove = table.remove
local utils_deg_rad = utils.degRad
local math_sqrt = math.sqrt
local math_sin = math.sin
local math_cos = math.cos

local SwirlEffect = {}
SwirlEffect.__index = SwirlEffect

function SwirlEffect.new (radius)
	local self = {
		worldX = 0,
		worldY = 0,
		centerX = 0,
		centerY = 0,
		radius = radius,
		angle = 0,
		interpolation = interpolation.pow2
	}
	setmetatable(self, SwirlEffect)

	return self
end

function SwirlEffect:beginEffect (skeleton)
	self.worldX = skeleton.x + self.centerX
	self.worldY = skeleton.y + self.centerY
	self.angleRad = self.angle * utils_deg_rad
end

function SwirlEffect:transform (vertex)
	local x = vertex.x - self.worldX
	local y = vertex.y - self.worldY
	local dist = math_sqrt(x * x + y * y)
	if (dist < self.radius) then		
		local theta = interpolation.apply(self.interpolation, 0, self.angleRad, (self.radius - dist) / self.radius)
		local cos = math_cos(theta)
		local sin = math_sin(theta)
		vertex.x = cos * x - sin * y + self.worldX
		vertex.y = sin * x + cos * y + self.worldY
	end
end

function SwirlEffect:endEffect ()
end

return SwirlEffect