/spacey

-- Class: Animation

-- An animation displays a sequence of frames. If you do not specify

-- a width and height for the sprite, it will size itself so that

-- it is a square, where each side is as tall as the source image's height.

--

--

-- Event: onEndSequence

-- Called whenever an animation sequence ends. It is passed the name

-- of the sequence that just ended.

-- 

-- Extends:

--		<Sprite>

Animation = Sprite:extend{

	-- Property: paused

	-- Set this to true to freeze the animation on the current frame.

	paused = false,

	-- Property: sequences

	-- A lookup table of sequences. Each one is stored by name and has

	-- the following properties:

	-- * name - string name for the sequence.

	-- * frames - table of frames to display. The first frame in the sheet is at index 1.

	-- * fps - frames per second.

	-- * loops - does the animation loop? defaults to true

	sequences = {},

	-- Property: image

	-- A string filename to the image to use as a sprite strip. A sprite

	-- strip can have multiple rows of frames.

	-- Property: currentSequence

	-- A reference to the current animation sequence table.

	-- Property: currentName

	-- The name of the current animation sequence.

	-- Property: currentFrame

	-- The current frame being displayed; starts at 1.

	-- Property: frameIndex

	-- Numeric index of the current frame in the current sequence; starts at 1.

	-- Property: frameTimer

	-- Time left before the animation changes to the next frame in seconds.

	-- Normally you shouldn't need to change this directly.

	-- private property: used to check whether the source image

	-- for our quad is up-to-date

	_set = {},

	-- private property imageObj: actual Image instance used to draw

	-- this is normally set via the image property, but you may set it directly

	-- so long as you never change that image property afterwards.

	new = function (self, obj)

		obj = obj or {}

		self:extend(obj)

		obj:updateQuad()

		if obj.onNew then obj:onNew() end

		return obj

	end,

	-- Method: play 

	-- Begins playing an animation in the sprite's library.

	-- If the animation is already playing, this has no effect.

	--

	-- Arguments:

	--		name - name of the animation

	--

	-- Returns:

	--		nothing

	play = function (self, name)

		if self.currentName == name and not self.paused then

			return

		end

		assert(self.sequences[name], 'no animation sequence named "' .. name .. '"')

		self.currentName = name

		self.currentSequence = self.sequences[name]

		self.frameIndex = 0

		self.frameTimer = 0

		self.paused = false

	end,

	-- Method: freeze

	-- Freezes the animation on the specified frame.

	--

	-- Arguments:

	--		* index - integer frame index relative to the entire sprite sheet,

	--				  starts at 1. If omitted, this freezes the current frame.

	--				  If there is no current frame, this freezes on the first frame.

	--

	-- Returns:

	--		nothing

	freeze = function (self, index)

		if self.currentSequence then

			index = index or self.currentSequence[self.frameIndex]

		end

		index = index or self.currentFrame or 1

		if self._set.image ~= self.image then

			self:updateQuad()

		end

		self.currentFrame = index

		self:updateFrame(index)

		self.paused = true

	end,

	-- private method: updateQuad

	-- sets up the sprite's quad property based on the image;

	-- needs to be called whenever the sprite's image property changes.

	--

	-- Arguments:

	--		none

	--

	-- Returns:

	--		nothing

	updateQuad = function (self)

		if self.image then 

			self._imageObj = Cached:image(self.image)

			if not self.width then self.width = self._imageObj:getHeight() end

			if not self.height then self.height = self.width end

			self._quad = love.graphics.newQuad(0, 0, self.width, self.height,

											  self._imageObj:getWidth(), self._imageObj:getHeight())

			self._imageWidth = self._imageObj:getWidth()

			self._set.image = self.image

		end

	end,

	-- private method: updateFrame

	-- changes the sprite's quad property based on the current frame;

	-- needs to be called whenever the sprite's currentFrame property changes.

	--

	-- Arguments:

	--		none

	--

	-- Returns:

	--		nothing

	updateFrame = function (self)

		assert(type(self.currentFrame) == 'number', "current frame is not a number")

		assert(self.image, "asked to set the frame of a nil image")

		if self._set.image ~= self.image then

			self:updateQuad()

		end

		local frameX = (self.currentFrame - 1) * self.width

		local viewportX = frameX % self._imageWidth

		local viewportY = self.height * math.floor(frameX / self._imageWidth)

		self._quad:setViewport(viewportX, viewportY, self.width, self.height)

	end,

	update = function (self, elapsed)

		-- move the animation frame forward

		if self.currentSequence and not self.paused then

			self.frameTimer = self.frameTimer - elapsed

			if self.frameTimer <= 0 then

				self.frameIndex = self.frameIndex + 1

				if self.frameIndex > #self.currentSequence.frames then

					if self.onEndSequence then self:onEndSequence(self.currentName) end

					if self.currentSequence.loops ~= false then

						self.frameIndex = 1

					else

						self.frameIndex = self.frameIndex - 1

						self.paused = true

					end

				end

				self.currentFrame = self.currentSequence.frames[self.frameIndex]

				self:updateFrame()

				self.frameTimer = 1 / self.currentSequence.fps

			end

		end

		Sprite.update(self, elapsed)

	end,

	draw = function (self, x, y)

		x = math.floor(x or self.x)

		y = math.floor(y or self.y)

		if STRICT then

			assert(type(x) == 'number', 'visible animation does not have a numeric x property')

			assert(type(y) == 'number', 'visible animation does not have a numeric y property')

			assert(type(self.width) == 'number', 'visible animation does not have a numeric width property')

			assert(type(self.height) == 'number', 'visible animation does not have a numeric height property')

		end

		if not self.visible or not self.image or self.alpha <= 0 then return end

		-- if our image changed, update the quad

		if self._set.image ~= self.image then

			self:updateQuad()

		end

		-- set color if needed

		local colored = self.alpha ~= 1 or self.tint[1] ~= 1 or self.tint[2] ~= 1 or self.tint[3] ~= 1

		if colored then

			love.graphics.setColor(self.tint[1] * 255, self.tint[2] * 255, self.tint[3] * 255, self.alpha * 255)

		end

		-- draw the quad

		local scaleX = self.scale * self.distort.x

		local scaleY = self.scale * self.distort.y

		if self.flipX then scaleX = scaleX * -1 end

		if self.flipY then scaleY = scaleY * -1 end

		love.graphics.drawq(self._imageObj, self._quad, x + self.width / 2, y + self.height / 2, self.rotation,

							scaleX, scaleY, self.width / 2, self.height / 2)

		-- reset color

		if colored then

			love.graphics.setColor(255, 255, 255, 255)

		end

	end,

	__tostring = function (self)

		local result = 'Animation (x: ' .. self.x .. ', y: ' .. self.y ..

					   ', w: ' .. self.width .. ', h: ' .. self.height .. ', '

		if self.currentName then

			result = result .. 'playing ' .. self.currentName .. ', '

		end

		result = result .. ' frame ' .. self.currentFrame .. ', '

		if self.active then

			result = result .. 'active, '

		else

			result = result .. 'inactive, '

		end

		if self.visible then

			result = result .. 'visible, '

		else

			result = result .. 'invisible, '

		end

		if self.solid then

			result = result .. 'solid'

		else

			result = result .. 'not solid'

		end

		return result .. ')'

	end

}