/ld26-basecode

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1 by Josh C
zoetrope 1.4
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-- Class: Animation
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-- An animation displays a sequence of frames. If you do not specify
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-- a width and height for the sprite, it will size itself so that
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-- it is a square, where each side is as tall as the source image's height.
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--
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--
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-- Event: onEndSequence
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-- Called whenever an animation sequence ends. It is passed the name
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-- of the sequence that just ended.
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-- 
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-- Extends:
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--		<Sprite>
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Animation = Sprite:extend{
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	-- Property: paused
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	-- Set this to true to freeze the animation on the current frame.
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	paused = false,
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	-- Property: sequences
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	-- A lookup table of sequences. Each one is stored by name and has
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	-- the following properties:
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	-- * name - string name for the sequence.
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	-- * frames - table of frames to display. The first frame in the sheet is at index 1.
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	-- * fps - frames per second.
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	-- * loops - does the animation loop? defaults to true
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	sequences = {},
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	-- Property: image
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	-- A string filename to the image to use as a sprite strip. A sprite
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	-- strip can have multiple rows of frames.
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	-- Property: currentSequence
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	-- A reference to the current animation sequence table.
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	-- Property: currentName
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	-- The name of the current animation sequence.
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	-- Property: currentFrame
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	-- The current frame being displayed; starts at 1.
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	-- Property: frameIndex
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	-- Numeric index of the current frame in the current sequence; starts at 1.
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	-- Property: frameTimer
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	-- Time left before the animation changes to the next frame in seconds.
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	-- Normally you shouldn't need to change this directly.
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	-- private property: used to check whether the source image
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	-- for our quad is up-to-date
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	_set = {},
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	-- private property imageObj: actual Image instance used to draw
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	-- this is normally set via the image property, but you may set it directly
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	-- so long as you never change that image property afterwards.
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	new = function (self, obj)
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		obj = obj or {}
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		self:extend(obj)
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		obj:updateQuad()
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		if obj.onNew then obj:onNew() end
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		return obj
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	end,
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	-- Method: play 
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	-- Begins playing an animation in the sprite's library.
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	-- If the animation is already playing, this has no effect.
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	--
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	-- Arguments:
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	--		name - name of the animation
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	--
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	-- Returns:
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	--		nothing
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	play = function (self, name)
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		if self.currentName == name and not self.paused then
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			return
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		end
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		assert(self.sequences[name], 'no animation sequence named "' .. name .. '"')
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		self.currentName = name
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		self.currentSequence = self.sequences[name]
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		self.frameIndex = 0
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		self.frameTimer = 0
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		self.paused = false
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	end,
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	-- Method: freeze
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	-- Freezes the animation on the specified frame.
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	--
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	-- Arguments:
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	--		* index - integer frame index relative to the entire sprite sheet,
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	--				  starts at 1. If omitted, this freezes the current frame.
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	--				  If there is no current frame, this freezes on the first frame.
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	--
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	-- Returns:
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	--		nothing
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	freeze = function (self, index)
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		if self.currentSequence then
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			index = index or self.currentSequence[self.frameIndex]
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		end
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		index = index or self.currentFrame or 1
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		if self._set.image ~= self.image then
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			self:updateQuad()
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		end
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		self.currentFrame = index
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		self:updateFrame(index)
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		self.paused = true
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	end,
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	-- private method: updateQuad
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	-- sets up the sprite's quad property based on the image;
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	-- needs to be called whenever the sprite's image property changes.
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	--
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	-- Arguments:
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	--		none
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	--
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	-- Returns:
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	--		nothing
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	updateQuad = function (self)
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		if self.image then 
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			self._imageObj = Cached:image(self.image)
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			if not self.width then self.width = self._imageObj:getHeight() end
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			if not self.height then self.height = self.width end
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			self._quad = love.graphics.newQuad(0, 0, self.width, self.height,
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											  self._imageObj:getWidth(), self._imageObj:getHeight())
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			self._imageWidth = self._imageObj:getWidth()
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			self._set.image = self.image
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		end
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	end,
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	-- private method: updateFrame
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	-- changes the sprite's quad property based on the current frame;
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	-- needs to be called whenever the sprite's currentFrame property changes.
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	--
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	-- Arguments:
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	--		none
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	--
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	-- Returns:
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	--		nothing
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	updateFrame = function (self)
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		assert(type(self.currentFrame) == 'number', "current frame is not a number")
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		assert(self.image, "asked to set the frame of a nil image")
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		if self._set.image ~= self.image then
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			self:updateQuad()
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		end
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		local frameX = (self.currentFrame - 1) * self.width
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		local viewportX = frameX % self._imageWidth
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		local viewportY = self.height * math.floor(frameX / self._imageWidth)
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		self._quad:setViewport(viewportX, viewportY, self.width, self.height)
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	end,
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	update = function (self, elapsed)
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		-- move the animation frame forward
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		if self.currentSequence and not self.paused then
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			self.frameTimer = self.frameTimer - elapsed
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			if self.frameTimer <= 0 then
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				self.frameIndex = self.frameIndex + 1
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				if self.frameIndex > #self.currentSequence.frames then
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					if self.onEndSequence then self:onEndSequence(self.currentName) end
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					if self.currentSequence.loops ~= false then
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						self.frameIndex = 1
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					else
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						self.frameIndex = self.frameIndex - 1
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						self.paused = true
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					end
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				end
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				self.currentFrame = self.currentSequence.frames[self.frameIndex]
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				self:updateFrame()
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				self.frameTimer = 1 / self.currentSequence.fps
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			end
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		end
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		Sprite.update(self, elapsed)
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	end,
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	draw = function (self, x, y)
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		x = math.floor(x or self.x)
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		y = math.floor(y or self.y)
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		if STRICT then
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			assert(type(x) == 'number', 'visible animation does not have a numeric x property')
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			assert(type(y) == 'number', 'visible animation does not have a numeric y property')
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			assert(type(self.width) == 'number', 'visible animation does not have a numeric width property')
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			assert(type(self.height) == 'number', 'visible animation does not have a numeric height property')
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		end
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		if not self.visible or not self.image or self.alpha <= 0 then return end
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		-- if our image changed, update the quad
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		if self._set.image ~= self.image then
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			self:updateQuad()
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		end
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		-- set color if needed
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		local colored = self.alpha ~= 1 or self.tint[1] ~= 1 or self.tint[2] ~= 1 or self.tint[3] ~= 1
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		if colored then
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			love.graphics.setColor(self.tint[1] * 255, self.tint[2] * 255, self.tint[3] * 255, self.alpha * 255)
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		end
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		-- draw the quad
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		local scaleX = self.scale * self.distort.x
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		local scaleY = self.scale * self.distort.y
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		if self.flipX then scaleX = scaleX * -1 end
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		if self.flipY then scaleY = scaleY * -1 end
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		love.graphics.drawq(self._imageObj, self._quad, x + self.width / 2, y + self.height / 2, self.rotation,
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							scaleX, scaleY, self.width / 2, self.height / 2)
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		-- reset color
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		if colored then
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			love.graphics.setColor(255, 255, 255, 255)
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		end
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	end,
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	__tostring = function (self)
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		local result = 'Animation (x: ' .. self.x .. ', y: ' .. self.y ..
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					   ', w: ' .. self.width .. ', h: ' .. self.height .. ', '
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		if self.currentName then
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			result = result .. 'playing ' .. self.currentName .. ', '
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		end
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		result = result .. ' frame ' .. self.currentFrame .. ', '
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		if self.active then
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			result = result .. 'active, '
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		else
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			result = result .. 'inactive, '
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		end
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		if self.visible then
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			result = result .. 'visible, '
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		else
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			result = result .. 'invisible, '
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		end
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		if self.solid then
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			result = result .. 'solid'
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		else
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			result = result .. 'not solid'
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		end
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		return result .. ')'
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	end
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}