First demo commit.

lib/30log.lua

@@ -0,0 +1,30 @@
+local assert, pairs, type, tostring, setmetatable = assert, pairs, type, tostring, setmetatable
+local baseMt, _instances, _classes, _class = {}, setmetatable({},{__mode='k'}), setmetatable({},{__mode='k'})
+local function assert_class(class, method) assert(_classes[class], ('Wrong method call. Expected class:%s.'):format(method)) end
+local function deep_copy(t, dest, aType) t = t or {}; local r = dest or {}
+  for k,v in pairs(t) do
+    if aType and type(v)==aType then r[k] = v elseif not aType then
+      if type(v) == 'table' and k ~= "__index" then r[k] = deep_copy(v) else r[k] = v end
+    end
+  end; return r
+end
+local function instantiate(self,...)
+  assert_class(self, 'new(...) or class(...)'); local instance = {class = self}; _instances[instance] = tostring(instance); setmetatable(instance,self)
+  if self.init then if type(self.init) == 'table' then deep_copy(self.init, instance) else self.init(instance, ...) end; end; return instance
+end
+local function extend(self, name, extra_params)
+  assert_class(self, 'extend(...)'); local heir = {}; _classes[heir] = tostring(heir); deep_copy(extra_params, deep_copy(self, heir));
+  heir.name, heir.__index, heir.super = extra_params and extra_params.name or name, heir, self; return setmetatable(heir,self)
+end
+baseMt = { __call = function (self,...) return self:new(...) end, __tostring = function(self,...)
+  if _instances[self] then return ("instance of '%s' (%s)"):format(rawget(self.class,'name') or '?', _instances[self]) end
+  return _classes[self] and ("class '%s' (%s)"):format(rawget(self,'name') or '?',_classes[self]) or self
+end}; _classes[baseMt] = tostring(baseMt); setmetatable(baseMt, {__tostring = baseMt.__tostring})
+local class = {isClass = function(class, ofsuper) local isclass = not not _classes[class]; if ofsuper then return isclass and (class.super == ofsuper) end; return isclass end, isInstance = function(instance, ofclass)
+	local isinstance = not not _instances[instance]; if ofclass then return isinstance and (instance.class == ofclass) end; return isinstance end}; _class = function(name, attr)
+  local c = deep_copy(attr); c.mixins=setmetatable({},{__mode='k'}); _classes[c] = tostring(c); c.name, c.__tostring, c.__call = name or c.name, baseMt.__tostring, baseMt.__call
+  c.include = function(self,mixin) assert_class(self, 'include(mixin)'); self.mixins[mixin] = true; return deep_copy(mixin, self, 'function') end
+  c.new, c.extend, c.__index, c.includes = instantiate, extend, c, function(self,mixin) assert_class(self,'includes(mixin)') return not not (self.mixins[mixin] or (self.super and self.super:includes(mixin))) end
+  c.extends = function(self, class) assert_class(self, 'extends(class)') local super = self; repeat super = super.super until (super == class or super == nil); return class and (super == class) end
+	return setmetatable(c, baseMt) end; class._DESCRIPTION = '30 lines library for object orientation in Lua'; class._VERSION = '30log v1.0.0'; class._URL = 'http://github.com/Yonaba/30log'; class._LICENSE = 'MIT LICENSE <http://www.opensource.org/licenses/mit-license.php>'
+return setmetatable(class,{__call = function(_,...) return _class(...) end })

lib/anim8.lua

@@ -0,0 +1,284 @@
+local anim8 = {
+  _VERSION     = 'anim8 v2.1.0',
+  _DESCRIPTION = 'An animation library for LÖVE',
+  _URL         = 'https://github.com/kikito/anim8',
+  _LICENSE     = [[
+    MIT LICENSE
+    Copyright (c) 2011 Enrique García Cota
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the
+    "Software"), to deal in the Software without restriction, including
+    without limitation the rights to use, copy, modify, merge, publish,
+    distribute, sublicense, and/or sell copies of the Software, and to
+    permit persons to whom the Software is furnished to do so, subject to
+    the following conditions:
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+  ]]
+}
+
+local Grid = {}
+
+local _frames = {}
+
+local function assertPositiveInteger(value, name)
+  if type(value) ~= 'number' then error(("%s should be a number, was %q"):format(name, tostring(value))) end
+  if value < 1 then error(("%s should be a positive number, was %d"):format(name, value)) end
+  if value ~= math.floor(value) then error(("%s should be an integer, was %d"):format(name, value)) end
+end
+
+local function createFrame(self, x, y)
+  local fw, fh = self.frameWidth, self.frameHeight
+  return love.graphics.newQuad(
+    self.left + (x-1) * fw + x * self.border,
+    self.top  + (y-1) * fh + y * self.border,
+    fw,
+    fh,
+    self.imageWidth,
+    self.imageHeight
+  )
+end
+
+local function getGridKey(...)
+  return table.concat( {...} ,'-' )
+end
+
+local function getOrCreateFrame(self, x, y)
+  if x < 1 or x > self.width or y < 1 or y > self.height then
+    error(("There is no frame for x=%d, y=%d"):format(x, y))
+  end
+  local key = self._key
+  _frames[key]       = _frames[key]       or {}
+  _frames[key][x]    = _frames[key][x]    or {}
+  _frames[key][x][y] = _frames[key][x][y] or createFrame(self, x, y)
+  return _frames[key][x][y]
+end
+
+local function parseInterval(str)
+  if type(str) == "number" then return str,str,1 end
+  str = str:gsub('%s', '') -- remove spaces
+  local min, max = str:match("^(%d+)-(%d+)$")
+  assert(min and max, ("Could not parse interval from %q"):format(str))
+  min, max = tonumber(min), tonumber(max)
+  local step = min <= max and 1 or -1
+  return min, max, step
+end
+
+function Grid:getFrames(...)
+  local result, args = {}, {...}
+  local minx, maxx, stepx, miny, maxy, stepy
+
+  for i=1, #args, 2 do
+    minx, maxx, stepx = parseInterval(args[i])
+    miny, maxy, stepy = parseInterval(args[i+1])
+    for y = miny, maxy, stepy do
+      for x = minx, maxx, stepx do
+        result[#result+1] = getOrCreateFrame(self,x,y)
+      end
+    end
+  end
+
+  return result
+end
+
+local Gridmt = {
+  __index = Grid,
+  __call  = Grid.getFrames
+}
+
+local function newGrid(frameWidth, frameHeight, imageWidth, imageHeight, left, top, border)
+  assertPositiveInteger(frameWidth,  "frameWidth")
+  assertPositiveInteger(frameHeight, "frameHeight")
+  assertPositiveInteger(imageWidth,  "imageWidth")
+  assertPositiveInteger(imageHeight, "imageHeight")
+
+  left   = left   or 0
+  top    = top    or 0
+  border = border or 0
+
+  local key  = getGridKey(frameWidth, frameHeight, imageWidth, imageHeight, left, top, border)
+
+  local grid = setmetatable(
+    { frameWidth  = frameWidth,
+      frameHeight = frameHeight,
+      imageWidth  = imageWidth,
+      imageHeight = imageHeight,
+      left        = left,
+      top         = top,
+      border      = border,
+      width       = math.floor(imageWidth/frameWidth),
+      height      = math.floor(imageHeight/frameHeight),
+      _key        = key
+    },
+    Gridmt
+  )
+  return grid
+end
+
+-----------------------------------------------------------
+
+local Animation = {}
+
+local function cloneArray(arr)
+  local result = {}
+  for i=1,#arr do result[i] = arr[i] end
+  return result
+end
+
+local function parseDurations(durations, frameCount)
+  local result = {}
+  if type(durations) == 'number' then
+    for i=1,frameCount do result[i] = durations end
+  else
+    local min, max, step
+    for key,duration in pairs(durations) do
+      assert(type(duration) == 'number', "The value [" .. tostring(duration) .. "] should be a number")
+      min, max, step = parseInterval(key)
+      for i = min,max,step do result[i] = duration end
+    end
+  end
+
+  if #result < frameCount then
+    error("The durations table has length of " .. tostring(#result) .. ", but it should be >= " .. tostring(frameCount))
+  end
+
+  return result
+end
+
+local function parseIntervals(durations)
+  local result, time = {0},0
+  for i=1,#durations do
+    time = time + durations[i]
+    result[i+1] = time
+  end
+  return result, time
+end
+
+local Animationmt = { __index = Animation }
+local nop = function() end
+
+local function newAnimation(frames, durations, onLoop)
+  local td = type(durations);
+  if (td ~= 'number' or durations <= 0) and td ~= 'table' then
+    error("durations must be a positive number. Was " .. tostring(durations) )
+  end
+  onLoop = onLoop or nop
+  durations = parseDurations(durations, #frames)
+  local intervals, totalDuration = parseIntervals(durations)
+  return setmetatable({
+      frames         = cloneArray(frames),
+      durations      = durations,
+      intervals      = intervals,
+      totalDuration  = totalDuration,
+      onLoop         = onLoop,
+      timer          = 0,
+      position       = 1,
+      status         = "playing",
+      flippedH       = false,
+      flippedV       = false
+    },
+    Animationmt
+  )
+end
+
+function Animation:clone()
+  local newAnim = newAnimation(self.frames, self.durations, self.onLoop)
+  newAnim.flippedH, newAnim.flippedV = self.flippedH, self.flippedV
+  return newAnim
+end
+
+function Animation:flipH()
+  self.flippedH = not self.flippedH
+  return self
+end
+
+function Animation:flipV()
+  self.flippedV = not self.flippedV
+  return self
+end
+
+local function seekFrameIndex(intervals, timer)
+  local high, low, i = #intervals-1, 1, 1
+
+  while(low <= high) do
+    i = math.floor((low + high) / 2)
+    if     timer >  intervals[i+1] then low  = i + 1
+    elseif timer <= intervals[i]   then high = i - 1
+    else
+      return i
+    end
+  end
+
+  return i
+end
+
+function Animation:update(dt)
+  if self.status ~= "playing" then return end
+
+  self.timer = self.timer + dt
+  local loops = math.floor(self.timer / self.totalDuration)
+  if loops ~= 0 then
+    self.timer = self.timer - self.totalDuration * loops
+    local f = type(self.onLoop) == 'function' and self.onLoop or self[self.onLoop]
+    f(self, loops)
+  end
+
+  self.position = seekFrameIndex(self.intervals, self.timer)
+end
+
+function Animation:pause()
+  self.status = "paused"
+end
+
+function Animation:gotoFrame(position)
+  self.position = position
+  self.timer = self.intervals[self.position]
+end
+
+function Animation:pauseAtEnd()
+  self.position = #self.frames
+  self.timer = self.totalDuration
+  self:pause()
+end
+
+function Animation:pauseAtStart()
+  self.position = 1
+  self.timer = 0
+  self:pause()
+end
+
+function Animation:resume()
+  self.status = "playing"
+end
+
+function Animation:draw(image, x, y, r, sx, sy, ox, oy, ...)
+  local frame = self.frames[self.position]
+  if self.flippedH or self.flippedV then
+    r,sx,sy,ox,oy = r or 0, sx or 1, sy or 1, ox or 0, oy or 0
+    local _,_,w,h = frame:getViewport()
+
+    if self.flippedH then
+      sx = sx * -1
+      ox = w - ox
+    end
+    if self.flippedV then
+      sy = sy * -1
+      oy = h - oy
+    end
+  end
+  love.graphics.draw(image, frame, x, y, r, sx, sy, ox, oy, ...)
+end
+
+-----------------------------------------------------------
+
+anim8.newGrid       = newGrid
+anim8.newAnimation  = newAnimation
+
+return anim8

lib/beholder.lua

@@ -0,0 +1,174 @@
+-- beholder.lua - v2.1.1 (2011-11)
+
+-- Copyright (c) 2011 Enrique García Cota
+-- Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+-- The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN callback OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+local function copy(t)
+  local c={}
+  for i=1,#t do c[i]=t[i] end
+  return c
+end
+
+local function hash2array(t)
+  local arr, i = {}, 0
+  for _,v in pairs(t) do
+    i = i+1
+    arr[i] = v
+  end
+  return arr, i
+end
+-- private Node class
+
+local nodesById = nil
+local root = nil
+
+local function newNode()
+  return { callbacks = {}, children = setmetatable({}, {__mode="k"}) }
+end
+
+
+local function findNodeById(id)
+  return nodesById[id]
+end
+
+local function findOrCreateChildNode(self, key)
+  self.children[key] = self.children[key] or newNode()
+  return self.children[key]
+end
+
+local function findOrCreateDescendantNode(self, keys)
+  local node = self
+  for i=1, #keys do
+    node = findOrCreateChildNode(node, keys[i])
+  end
+  return node
+end
+
+local function invokeNodeCallbacks(self, params)
+  -- copy the hash into an array, for safety (self-erasures)
+  local callbacks, count = hash2array(self.callbacks)
+  for i=1,#callbacks do
+    callbacks[i](unpack(params))
+  end
+  return count
+end
+
+local function invokeAllNodeCallbacksInSubTree(self, params)
+  local counter = invokeNodeCallbacks(self, params)
+  for _,child in pairs(self.children) do
+    counter = counter + invokeAllNodeCallbacksInSubTree(child, params)
+  end
+  return counter
+end
+
+local function invokeNodeCallbacksFromPath(self, path)
+  local node = self
+  local params = copy(path)
+  local counter = invokeNodeCallbacks(node, params)
+
+  for i=1, #path do
+    node = node.children[path[i]]
+    if not node then break end
+    table.remove(params, 1)
+    counter = counter + invokeNodeCallbacks(node, params)
+  end
+
+  return counter
+end
+
+local function addCallbackToNode(self, callback)
+  local id = {}
+  self.callbacks[id] = callback
+  nodesById[id] = self
+  return id
+end
+
+local function removeCallbackFromNode(self, id)
+  self.callbacks[id] = nil
+  nodesById[id] = nil
+end
+
+
+------ beholder table
+
+local beholder = {}
+
+
+-- beholder private functions/vars
+
+local groups = nil
+local currentGroupId = nil
+
+local function addIdToCurrentGroup(id)
+  if currentGroupId then
+    groups[currentGroupId] = groups[currentGroupId] or setmetatable({}, {__mode="k"})
+    local group = groups[currentGroupId]
+    group[#group + 1] = id
+  end
+  return id
+end
+
+local function stopObservingGroup(group)
+  local count = #group
+  for i=1,count do
+    beholder.stopObserving(group[i])
+  end
+  return count
+end
+
+local function falseIfZero(n)
+  return n > 0 and n
+end
+
+local function extractEventAndCallbackFromParams(params)
+  assert(#params > 0, "beholder.observe requires at least one parameter - the callback. You usually want to use two, i.e.: beholder.observe('EVENT', callback)")
+  local callback = table.remove(params, #params)
+  return params, callback
+end
+
+
+------ Public interface
+
+function beholder.observe(...)
+  local event, callback = extractEventAndCallbackFromParams({...})
+  local node = findOrCreateDescendantNode(root, event)
+  return addIdToCurrentGroup(addCallbackToNode(node, callback))
+end
+
+function beholder.stopObserving(id)
+  local node = findNodeById(id)
+  if node then removeCallbackFromNode(node, id) end
+
+  local group, count = groups[id], 0
+  if group then count = stopObservingGroup(group) end
+
+  return (node or count > 0) and true or false
+end
+
+function beholder.group(groupId, f)
+  assert(not currentGroupId, "beholder.group can not be nested!")
+  currentGroupId = groupId
+  f()
+  currentGroupId = nil
+end
+
+function beholder.trigger(...)
+  return falseIfZero( invokeNodeCallbacksFromPath(root, {...}) )
+end
+
+function beholder.triggerAll(...)
+  return falseIfZero( invokeAllNodeCallbacksInSubTree(root, {...}) )
+end
+
+function beholder.reset()
+  root = newNode()
+  nodesById = setmetatable({}, {__mode="k"})
+  groups = {}
+  currentGroupId = nil
+end
+
+beholder.reset()
+
+return beholder

lib/bump.lua

@@ -0,0 +1,770 @@
+local bump = {
+  _VERSION     = 'bump v3.1.2',
+  _URL         = 'https://github.com/kikito/bump.lua',
+  _DESCRIPTION = 'A collision detection library for Lua',
+  _LICENSE     = [[
+    MIT LICENSE
+
+    Copyright (c) 2014 Enrique García Cota
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the
+    "Software"), to deal in the Software without restriction, including
+    without limitation the rights to use, copy, modify, merge, publish,
+    distribute, sublicense, and/or sell copies of the Software, and to
+    permit persons to whom the Software is furnished to do so, subject to
+    the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+  ]]
+}
+
+------------------------------------------
+-- Auxiliary functions
+------------------------------------------
+
+local abs, floor, ceil, min, max = math.abs, math.floor, math.ceil, math.min, math.max
+
+local function sign(x)
+  if x > 0 then return 1 end
+  if x == 0 then return 0 end
+  return -1
+end
+
+local function nearest(x, a, b)
+  if abs(a - x) < abs(b - x) then return a else return b end
+end
+
+local function assertType(desiredType, value, name)
+  if type(value) ~= desiredType then
+    error(name .. ' must be a ' .. desiredType .. ', but was ' .. tostring(value) .. '(a ' .. type(value) .. ')')
+  end
+end
+
+local function assertIsPositiveNumber(value, name)
+  if type(value) ~= 'number' or value <= 0 then
+    error(name .. ' must be a positive integer, but was ' .. tostring(value) .. '(' .. type(value) .. ')')
+  end
+end
+
+local function assertIsRect(x,y,w,h)
+  assertType('number', x, 'x')
+  assertType('number', y, 'y')
+  assertIsPositiveNumber(w, 'w')
+  assertIsPositiveNumber(h, 'h')
+end
+
+local defaultFilter = function()
+  return 'slide'
+end
+
+------------------------------------------
+-- Rectangle functions
+------------------------------------------
+
+local function rect_getNearestCorner(x,y,w,h, px, py)
+  return nearest(px, x, x+w), nearest(py, y, y+h)
+end
+
+-- This is a generalized implementation of the liang-barsky algorithm, which also returns
+-- the normals of the sides where the segment intersects.
+-- Returns nil if the segment never touches the rect
+-- Notice that normals are only guaranteed to be accurate when initially ti1, ti2 == -math.huge, math.huge
+local function rect_getSegmentIntersectionIndices(x,y,w,h, x1,y1,x2,y2, ti1,ti2)
+  ti1, ti2 = ti1 or 0, ti2 or 1
+  local dx, dy = x2-x1, y2-y1
+  local nx, ny
+  local nx1, ny1, nx2, ny2 = 0,0,0,0
+  local p, q, r
+
+  for side = 1,4 do
+    if     side == 1 then nx,ny,p,q = -1,  0, -dx, x1 - x     -- left
+    elseif side == 2 then nx,ny,p,q =  1,  0,  dx, x + w - x1 -- right
+    elseif side == 3 then nx,ny,p,q =  0, -1, -dy, y1 - y     -- top
+    else                  nx,ny,p,q =  0,  1,  dy, y + h - y1 -- bottom
+    end
+
+    if p == 0 then
+      if q <= 0 then return nil end
+    else
+      r = q / p
+      if p < 0 then
+        if     r > ti2 then return nil
+        elseif r > ti1 then ti1,nx1,ny1 = r,nx,ny
+        end
+      else -- p > 0
+        if     r < ti1 then return nil
+        elseif r < ti2 then ti2,nx2,ny2 = r,nx,ny
+        end
+      end
+    end
+  end
+
+  return ti1,ti2, nx1,ny1, nx2,ny2
+end
+
+-- Calculates the minkowsky difference between 2 rects, which is another rect
+local function rect_getDiff(x1,y1,w1,h1, x2,y2,w2,h2)
+  return x2 - x1 - w1,
+         y2 - y1 - h1,
+         w1 + w2,
+         h1 + h2
+end
+
+local delta = 0.00001 -- floating-point-safe comparisons here, otherwise bugs
+local function rect_containsPoint(x,y,w,h, px,py)
+  return px - x > delta      and py - y > delta and
+         x + w - px > delta  and y + h - py > delta
+end
+
+local function rect_isIntersecting(x1,y1,w1,h1, x2,y2,w2,h2)
+  return x1 < x2+w2 and x2 < x1+w1 and
+         y1 < y2+h2 and y2 < y1+h1
+end
+
+local function rect_getSquareDistance(x1,y1,w1,h1, x2,y2,w2,h2)
+  local dx = x1 - x2 + (w1 - w2)/2
+  local dy = y1 - y2 + (h1 - h2)/2
+  return dx*dx + dy*dy
+end
+
+local function rect_detectCollision(x1,y1,w1,h1, x2,y2,w2,h2, goalX, goalY)
+  goalX = goalX or x1
+  goalY = goalY or y1
+
+  local dx, dy      = goalX - x1, goalY - y1
+  local x,y,w,h     = rect_getDiff(x1,y1,w1,h1, x2,y2,w2,h2)
+
+  local overlaps, ti, nx, ny
+
+  if rect_containsPoint(x,y,w,h, 0,0) then -- item was intersecting other
+    local px, py    = rect_getNearestCorner(x,y,w,h, 0, 0)
+    local wi, hi    = min(w1, abs(px)), min(h1, abs(py)) -- area of intersection
+    ti              = -wi * hi -- ti is the negative area of intersection
+    overlaps = true
+  else
+    local ti1,ti2,nx1,ny1 = rect_getSegmentIntersectionIndices(x,y,w,h, 0,0,dx,dy, -math.huge, math.huge)
+
+    -- item tunnels into other
+    if ti1 and ti1 < 1 and (0 < ti1 or 0 == ti1 and ti2 > 0) then
+      ti, nx, ny = ti1, nx1, ny1
+      overlaps   = false
+    end
+  end
+
+  if not ti then return end
+
+  local tx, ty
+
+  if overlaps then
+    if dx == 0 and dy == 0 then
+      -- intersecting and not moving - use minimum displacement vector
+      local px, py = rect_getNearestCorner(x,y,w,h, 0,0)
+      if abs(px) < abs(py) then py = 0 else px = 0 end
+      nx, ny = sign(px), sign(py)
+      tx, ty = x1 + px, y1 + py
+    else
+      -- intersecting and moving - move in the opposite direction
+      local ti1
+      ti1,_,nx,ny = rect_getSegmentIntersectionIndices(x,y,w,h, 0,0,dx,dy, -math.huge, 1)
+      tx, ty = x1 + dx * ti1, y1 + dy * ti1
+    end
+  else -- tunnel
+    tx, ty = x1 + dx * ti, y1 + dy * ti
+  end
+
+  return {
+    overlaps  = overlaps,
+    ti        = ti,
+    move      = {x = dx, y = dy},
+    normal    = {x = nx, y = ny},
+    touch     = {x = tx, y = ty},
+    itemRect  = {x = x1, y = y1, w = w1, h = h1},
+    otherRect = {x = x2, y = y2, w = w2, h = h2}
+  }
+end
+
+------------------------------------------
+-- Grid functions
+------------------------------------------
+
+local function grid_toWorld(cellSize, cx, cy)
+  return (cx - 1)*cellSize, (cy-1)*cellSize
+end
+
+local function grid_toCell(cellSize, x, y)
+  return floor(x / cellSize) + 1, floor(y / cellSize) + 1
+end
+
+-- grid_traverse* functions are based on "A Fast Voxel Traversal Algorithm for Ray Tracing",
+-- by John Amanides and Andrew Woo - http://www.cse.yorku.ca/~amana/research/grid.pdf
+-- It has been modified to include both cells when the ray "touches a grid corner",
+-- and with a different exit condition
+
+local function grid_traverse_initStep(cellSize, ct, t1, t2)
+  local v = t2 - t1
+  if     v > 0 then
+    return  1,  cellSize / v, ((ct + v) * cellSize - t1) / v
+  elseif v < 0 then
+    return -1, -cellSize / v, ((ct + v - 1) * cellSize - t1) / v
+  else
+    return 0, math.huge, math.huge
+  end
+end
+
+local function grid_traverse(cellSize, x1,y1,x2,y2, f)
+  local cx1,cy1        = grid_toCell(cellSize, x1,y1)
+  local cx2,cy2        = grid_toCell(cellSize, x2,y2)
+  local stepX, dx, tx  = grid_traverse_initStep(cellSize, cx1, x1, x2)
+  local stepY, dy, ty  = grid_traverse_initStep(cellSize, cy1, y1, y2)
+  local cx,cy          = cx1,cy1
+
+  f(cx, cy)
+
+  -- The default implementation had an infinite loop problem when
+  -- approaching the last cell in some occassions. We finish iterating
+  -- when we are *next* to the last cell
+  while abs(cx - cx2) + abs(cy - cy2) > 1 do
+    if tx < ty then
+      tx, cx = tx + dx, cx + stepX
+      f(cx, cy)
+    else
+      -- Addition: include both cells when going through corners
+      if tx == ty then f(cx + stepX, cy) end
+      ty, cy = ty + dy, cy + stepY
+      f(cx, cy)
+    end
+  end
+
+  -- If we have not arrived to the last cell, use it
+  if cx ~= cx2 or cy ~= cy2 then f(cx2, cy2) end
+
+end
+
+local function grid_toCellRect(cellSize, x,y,w,h)
+  local cx,cy = grid_toCell(cellSize, x, y)
+  local cr,cb = ceil((x+w) / cellSize), ceil((y+h) / cellSize)
+  return cx, cy, cr - cx + 1, cb - cy + 1
+end
+
+------------------------------------------
+-- Responses
+------------------------------------------
+
+local touch = function(world, col, x,y,w,h, goalX, goalY, filter)
+  local touch = col.touch
+  return touch.x, touch.y, {}, 0
+end
+
+local cross = function(world, col, x,y,w,h, goalX, goalY, filter)
+  local touch = col.touch
+  local cols, len = world:project(col.item, x,y,w,h, goalX, goalY, filter)
+  return goalX, goalY, cols, len
+end
+
+local slide = function(world, col, x,y,w,h, goalX, goalY, filter)
+  goalX = goalX or x
+  goalY = goalY or y
+
+  local touch, move  = col.touch, col.move
+  local sx, sy       = touch.x, touch.y
+  if move.x ~= 0 or move.y ~= 0 then
+    if col.normal.x == 0 then
+      sx = goalX
+    else
+      sy = goalY
+    end
+  end
+
+  col.slide = {x = sx, y = sy}
+
+  x,y          = touch.x, touch.y
+  goalX, goalY = sx, sy
+  local cols, len  = world:project(col.item, x,y,w,h, goalX, goalY, filter)
+  return goalX, goalY, cols, len
+end
+
+local bounce = function(world, col, x,y,w,h, goalX, goalY, filter)
+  goalX = goalX or x
+  goalY = goalY or y
+
+  local touch, move = col.touch, col.move
+  local tx, ty = touch.x, touch.y
+
+  local bx, by, bnx, bny = tx, ty, 0,0
+
+  if move.x ~= 0 or move.y ~= 0 then
+    bnx, bny = goalX - tx, goalY - ty
+    if col.normal.x == 0 then bny = -bny else bnx = -bnx end
+    bx, by = tx + bnx, ty + bny
+  end
+
+  col.bounce   = {x = bx,  y = by}
+  x,y          = touch.x, touch.y
+  goalX, goalY = bx, by
+
+  local cols, len    = world:project(col.item, x,y,w,h, goalX, goalY, filter)
+  return goalX, goalY, cols, len
+end
+
+local onewayplatform = function(world, col, x,y,w,h, goalX, goalY, filter)
+  if col.normal.y < 0 and not col.overlaps then
+      col.didTouch = true
+      goalX, goalY, cols, len = slide(world, col, x,y,w,h, goalX, goalY, filter)
+      return goalX, goalY, cols, len
+  else
+      goalX, goalY, cols, len = cross(world, col, x,y,w,h, goalX, goalY, filter)
+      return goalX, goalY, cols, len
+  end
+end
+
+local onewayplatformTouch = function(world, col, x,y,w,h, goalX, goalY, filter)
+  if col.normal.y < 0 and not col.overlaps then
+      col.didTouch = true
+      goalX, goalY, cols, len = touch(world, col, x,y,w,h, goalX, goalY, filter)
+      return goalX, goalY, cols, len
+  else
+      goalX, goalY, cols, len = cross(world, col, x,y,w,h, goalX, goalY, filter)
+      return goalX, goalY, cols, len
+  end
+end
+
+------------------------------------------
+-- World
+------------------------------------------
+
+local World = {}
+local World_mt = {__index = World}
+
+-- Private functions and methods
+
+local function sortByWeight(a,b) return a.weight < b.weight end
+
+local function sortByTiAndDistance(a,b)
+  if a.ti == b.ti then
+    local ir, ar, br = a.itemRect, a.otherRect, b.otherRect
+    local ad = rect_getSquareDistance(ir.x,ir.y,ir.w,ir.h, ar.x,ar.y,ar.w,ar.h)
+    local bd = rect_getSquareDistance(ir.x,ir.y,ir.w,ir.h, br.x,br.y,br.w,br.h)
+    return ad < bd
+  end
+  return a.ti < b.ti
+end
+
+local function addItemToCell(self, item, cx, cy)
+  self.rows[cy] = self.rows[cy] or setmetatable({}, {__mode = 'v'})
+  local row = self.rows[cy]
+  row[cx] = row[cx] or {itemCount = 0, x = cx, y = cy, items = setmetatable({}, {__mode = 'k'})}
+  local cell = row[cx]
+  self.nonEmptyCells[cell] = true
+  if not cell.items[item] then
+    cell.items[item] = true
+    cell.itemCount = cell.itemCount + 1
+  end
+end
+
+local function removeItemFromCell(self, item, cx, cy)
+  local row = self.rows[cy]
+  if not row or not row[cx] or not row[cx].items[item] then return false end
+
+  local cell = row[cx]
+  cell.items[item] = nil
+  cell.itemCount = cell.itemCount - 1
+  if cell.itemCount == 0 then
+    self.nonEmptyCells[cell] = nil
+  end
+  return true
+end
+
+local function getDictItemsInCellRect(self, cl,ct,cw,ch)
+  local items_dict = {}
+  for cy=ct,ct+ch-1 do
+    local row = self.rows[cy]
+    if row then
+      for cx=cl,cl+cw-1 do
+        local cell = row[cx]
+        if cell and cell.itemCount > 0 then -- no cell.itemCount > 1 because tunneling
+          for item,_ in pairs(cell.items) do
+            items_dict[item] = true
+          end
+        end
+      end
+    end
+  end
+
+  return items_dict
+end
+
+local function getCellsTouchedBySegment(self, x1,y1,x2,y2)
+
+  local cells, cellsLen, visited = {}, 0, {}
+
+  grid_traverse(self.cellSize, x1,y1,x2,y2, function(cx, cy)
+    local row  = self.rows[cy]
+    if not row then return end
+    local cell = row[cx]
+    if not cell or visited[cell] then return end
+
+    visited[cell] = true
+    cellsLen = cellsLen + 1
+    cells[cellsLen] = cell
+  end)
+
+  return cells, cellsLen
+end
+
+local function getInfoAboutItemsTouchedBySegment(self, x1,y1, x2,y2, filter)
+  local cells, len = getCellsTouchedBySegment(self, x1,y1,x2,y2)
+  local cell, rect, l,t,w,h, ti1,ti2, tii0,tii1
+  local visited, itemInfo, itemInfoLen = {},{},0
+  for i=1,len do
+    cell = cells[i]
+    for item in pairs(cell.items) do
+      if not visited[item] then
+        visited[item]  = true
+        if (not filter or filter(item)) then
+          rect           = self.rects[item]
+          l,t,w,h        = rect.x,rect.y,rect.w,rect.h
+
+          ti1,ti2 = rect_getSegmentIntersectionIndices(l,t,w,h, x1,y1, x2,y2, 0, 1)
+          if ti1 and ((0 < ti1 and ti1 < 1) or (0 < ti2 and ti2 < 1)) then
+            -- the sorting is according to the t of an infinite line, not the segment
+            tii0,tii1    = rect_getSegmentIntersectionIndices(l,t,w,h, x1,y1, x2,y2, -math.huge, math.huge)
+            itemInfoLen  = itemInfoLen + 1
+            itemInfo[itemInfoLen] = {item = item, ti1 = ti1, ti2 = ti2, weight = min(tii0,tii1)}
+          end
+        end
+      end
+    end
+  end
+  table.sort(itemInfo, sortByWeight)
+  return itemInfo, itemInfoLen
+end
+
+local function getResponseByName(self, name)
+  local response = self.responses[name]
+  if not response then
+    error(('Unknown collision type: %s (%s)'):format(name, type(name)))
+  end
+  return response
+end
+
+
+-- Misc Public Methods
+
+function World:addResponse(name, response)
+  self.responses[name] = response
+end
+
+function World:project(item, x,y,w,h, goalX, goalY, filter)
+  assertIsRect(x,y,w,h)
+
+  goalX = goalX or x
+  goalY = goalY or y
+  filter  = filter  or defaultFilter
+
+  local collisions, len = {}, 0
+
+  local visited = {}
+  if item ~= nil then visited[item] = true end
+
+  -- This could probably be done with less cells using a polygon raster over the cells instead of a
+  -- bounding rect of the whole movement. Conditional to building a queryPolygon method
+  local tl, tt = min(goalX, x),       min(goalY, y)
+  local tr, tb = max(goalX + w, x+w), max(goalY + h, y+h)
+  local tw, th = tr-tl, tb-tt
+
+  local cl,ct,cw,ch = grid_toCellRect(self.cellSize, tl,tt,tw,th)
+
+  local dictItemsInCellRect = getDictItemsInCellRect(self, cl,ct,cw,ch)
+
+  for other,_ in pairs(dictItemsInCellRect) do
+    if not visited[other] then
+      visited[other] = true
+
+      local responseName = filter(item, other)
+      if responseName then
+        local ox,oy,ow,oh   = self:getRect(other)
+        local col           = rect_detectCollision(x,y,w,h, ox,oy,ow,oh, goalX, goalY)
+
+        if col then
+          col.other    = other
+          col.item     = item
+          col.type     = responseName
+
+          len = len + 1
+          collisions[len] = col
+        end
+      end
+    end
+  end
+
+  table.sort(collisions, sortByTiAndDistance)
+
+  return collisions, len
+end
+
+function World:countCells()
+  local count = 0
+  for _,row in pairs(self.rows) do
+    for _,_ in pairs(row) do
+      count = count + 1
+    end
+  end
+  return count
+end
+
+function World:hasItem(item)
+  return not not self.rects[item]
+end
+
+function World:getItems()
+  local items, len = {}, 0
+  for item,_ in pairs(self.rects) do
+    len = len + 1
+    items[len] = item
+  end
+  return items, len
+end
+
+function World:countItems()
+  local len = 0
+  for _ in pairs(self.rects) do len = len + 1 end
+  return len
+end
+
+function World:getRect(item)
+  local rect = self.rects[item]
+  if not rect then
+    error('Item ' .. tostring(item) .. ' must be added to the world before getting its rect. Use world:add(item, x,y,w,h) to add it first.')
+  end
+  return rect.x, rect.y, rect.w, rect.h
+end
+
+function World:toWorld(cx, cy)
+  return grid_toWorld(self.cellSize, cx, cy)
+end
+
+function World:toCell(x,y)
+  return grid_toCell(self.cellSize, x, y)
+end
+
+
+--- Query methods
+
+function World:queryRect(x,y,w,h, filter)
+
+  local cl,ct,cw,ch = grid_toCellRect(self.cellSize, x,y,w,h)
+  local dictItemsInCellRect = getDictItemsInCellRect(self, cl,ct,cw,ch)
+
+  local items, len = {}, 0
+
+  local rect
+  for item,_ in pairs(dictItemsInCellRect) do
+    rect = self.rects[item]
+    if (not filter or filter(item))
+    and rect_isIntersecting(x,y,w,h, rect.x, rect.y, rect.w, rect.h)
+    then
+      len = len + 1
+      items[len] = item
+    end
+  end
+
+  return items, len
+end
+
+function World:queryPoint(x,y, filter)
+  local cx,cy = self:toCell(x,y)
+  local dictItemsInCellRect = getDictItemsInCellRect(self, cx,cy,1,1)
+
+  local items, len = {}, 0
+
+  local rect
+  for item,_ in pairs(dictItemsInCellRect) do
+    rect = self.rects[item]
+    if (not filter or filter(item))
+    and rect_containsPoint(rect.x, rect.y, rect.w, rect.h, x, y)
+    then
+      len = len + 1
+      items[len] = item
+    end
+  end
+
+  return items, len
+end
+
+function World:querySegment(x1, y1, x2, y2, filter)
+  local itemInfo, len = getInfoAboutItemsTouchedBySegment(self, x1, y1, x2, y2, filter)
+  local items = {}
+  for i=1, len do
+    items[i] = itemInfo[i].item
+  end
+  return items, len
+end
+
+function World:querySegmentWithCoords(x1, y1, x2, y2, filter)
+  local itemInfo, len = getInfoAboutItemsTouchedBySegment(self, x1, y1, x2, y2, filter)
+  local dx, dy        = x2-x1, y2-y1
+  local info, ti1, ti2
+  for i=1, len do
+    info  = itemInfo[i]
+    ti1   = info.ti1
+    ti2   = info.ti2
+
+    info.weight  = nil
+    info.x1      = x1 + dx * ti1
+    info.y1      = y1 + dy * ti1
+    info.x2      = x1 + dx * ti2
+    info.y2      = y1 + dy * ti2
+  end
+  return itemInfo, len
+end
+
+
+--- Main methods
+
+function World:add(item, x,y,w,h)
+  local rect = self.rects[item]
+  if rect then
+    error('Item ' .. tostring(item) .. ' added to the world twice.')
+  end
+  assertIsRect(x,y,w,h)
+
+  self.rects[item] = {x=x,y=y,w=w,h=h}
+
+  local cl,ct,cw,ch = grid_toCellRect(self.cellSize, x,y,w,h)
+  for cy = ct, ct+ch-1 do
+    for cx = cl, cl+cw-1 do
+      addItemToCell(self, item, cx, cy)
+    end
+  end
+
+  return item
+end
+
+function World:remove(item)
+  local x,y,w,h = self:getRect(item)
+
+  self.rects[item] = nil
+  local cl,ct,cw,ch = grid_toCellRect(self.cellSize, x,y,w,h)
+  for cy = ct, ct+ch-1 do
+    for cx = cl, cl+cw-1 do
+      removeItemFromCell(self, item, cx, cy)
+    end
+  end
+end
+
+function World:update(item, x2,y2,w2,h2)
+  local x,y,w,h = self:getRect(item)
+  w2,h2 = w2 or w, h2 or h
+  assertIsRect(x2,y2,w2,h2)
+  if x ~= x2 or y ~= y2 or w ~= w2 or h ~= h2 then
+    local cellSize = self.cellSize
+    local cl1,ct1,cw1,ch1 = grid_toCellRect(cellSize, x,y,w,h)
+    local cl2,ct2,cw2,ch2 = grid_toCellRect(cellSize, x2,y2,w2,h2)
+    if cl1==cl2 and ct1==ct2 and cw1==cw2 and ch1==ch2 then
+      local rect = self.rects[item]
+      rect.x, rect.y, rect.w, rect.h = x2,y2,w2,h2
+    else
+      self:remove(item)
+      self:add(item, x2,y2,w2,h2)
+    end
+  end
+end
+
+function World:move(item, goalX, goalY, filter)
+  local actualX, actualY, cols, len = self:check(item, goalX, goalY, filter)
+
+  self:update(item, actualX, actualY)
+
+  return actualX, actualY, cols, len
+end
+
+function World:check(item, goalX, goalY, filter)
+  filter = filter or defaultFilter
+
+  local visited = {[item] = true}
+  local visitedFilter = function(item, other)
+    if visited[other] then return false end
+    return filter(item, other)
+  end
+
+  local cols, len = {}, 0
+
+  local x,y,w,h = self:getRect(item)
+
+  local projected_cols, projected_len = self:project(item, x,y,w,h, goalX,goalY, visitedFilter)
+
+  while projected_len > 0 do
+    local col = projected_cols[1]
+    len       = len + 1
+    cols[len] = col
+
+    visited[col.other] = true
+
+    local response = getResponseByName(self, col.type)
+
+    goalX, goalY, projected_cols, projected_len = response(
+      self,
+      col,
+      x, y, w, h,
+      goalX, goalY,
+      visitedFilter
+    )
+  end
+
+  return goalX, goalY, cols, len
+end
+
+
+-- Public library functions
+
+bump.newWorld = function(cellSize)
+  cellSize = cellSize or 64
+  assertIsPositiveNumber(cellSize, 'cellSize')
+  local world = setmetatable({
+    cellSize       = cellSize,
+    rects          = {},
+    rows           = {},
+    nonEmptyCells  = {},
+    responses = {}
+  }, World_mt)
+
+  world:addResponse('touch', touch)
+  world:addResponse('cross', cross)
+  world:addResponse('slide', slide)
+  world:addResponse('bounce', bounce)
+  -- modified here
+  world:addResponse('onewayplatform', onewayplatform)
+  world:addResponse('onewayplatformTouch', onewayplatformTouch)
+  -- to here
+
+  return world
+end
+
+bump.rect = {
+  getNearestCorner              = rect_getNearestCorner,
+  getSegmentIntersectionIndices = rect_getSegmentIntersectionIndices,
+  getDiff                       = rect_getDiff,
+  containsPoint                 = rect_containsPoint,
+  isIntersecting                = rect_isIntersecting,
+  getSquareDistance             = rect_getSquareDistance,
+  detectCollision               = rect_detectCollision
+}
+
+bump.responses = {
+  touch  = touch,
+  cross  = cross,
+  slide  = slide,
+  bounce = bounce
+}
+
+return bump

lib/gamera.lua

@@ -0,0 +1,210 @@
+-- gamera.lua v1.0.1
+
+-- Copyright (c) 2012 Enrique García Cota
+-- Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+-- The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+-- Based on YaciCode, from Julien Patte and LuaObject, from Sebastien Rocca-Serra
+
+local gamera = {}
+
+-- Private attributes and methods
+
+local gameraMt = {__index = gamera}
+local abs, min, max = math.abs, math.min, math.max
+
+local function clamp(x, minX, maxX)
+  return x < minX and minX or (x>maxX and maxX or x)
+end
+
+local function checkNumber(value, name)
+  if type(value) ~= 'number' then
+    error(name .. " must be a number (was: " .. tostring(value) .. ")")
+  end
+end
+
+local function checkPositiveNumber(value, name)
+  if type(value) ~= 'number' or value <=0 then
+    error(name .. " must be a positive number (was: " .. tostring(value) ..")")
+  end
+end
+
+local function checkAABB(l,t,w,h)
+  checkNumber(l, "l")
+  checkNumber(t, "t")
+  checkPositiveNumber(w, "w")
+  checkPositiveNumber(h, "h")
+end
+
+local function getVisibleArea(self, scale)
+  scale = scale or self.scale
+  local sin, cos = abs(self.sin), abs(self.cos)
+  local w,h = self.w / scale, self.h / scale
+  w,h = cos*w + sin*h, sin*w + cos*h
+  return min(w,self.ww), min(h, self.wh)
+end
+
+local function cornerTransform(self, x,y)
+  local scale, sin, cos = self.scale, self.sin, self.cos
+  x,y = x - self.x, y - self.y
+  x,y = -cos*x + sin*y, -sin*x - cos*y
+  return self.x - (x/scale + self.l), self.y - (y/scale + self.t)
+end
+
+local function adjustPosition(self)
+  local wl,wt,ww,wh = self.wl, self.wt, self.ww, self.wh
+  local w,h = getVisibleArea(self)
+  local w2,h2 = w*0.5, h*0.5
+
+  local left, right  = wl + w2, wl + ww - w2
+  local top,  bottom = wt + h2, wt + wh - h2
+
+  self.x, self.y = clamp(self.x, left, right), clamp(self.y, top, bottom)
+end
+
+local function adjustScale(self)
+  local w,h,ww,wh = self.w, self.h, self.ww, self.wh
+  local rw,rh     = getVisibleArea(self, 1)      -- rotated frame: area around the window, rotated without scaling
+  local sx,sy     = rw/ww, rh/wh                 -- vert/horiz scale: minimun scales that the window needs to occupy the world
+  local rscale    = max(sx,sy)
+
+  self.scale = max(self.scale, rscale)
+end
+
+-- Public interface
+
+function gamera.new(l,t,w,h)
+
+  local sw,sh = love.graphics.getWidth(), love.graphics.getHeight()
+
+  local cam = setmetatable({
+    x=0, y=0,
+    scale=1,
+    angle=0, sin=math.sin(0), cos=math.cos(0),
+    l=0, t=0, w=sw, h=sh, w2=sw*0.5, h2=sh*0.5
+  }, gameraMt)
+
+  cam:setWorld(l,t,w,h)
+
+  return cam
+end
+
+function gamera:setWorld(l,t,w,h)
+  checkAABB(l,t,w,h)
+
+  self.wl, self.wt, self.ww, self.wh = l,t,w,h
+
+  adjustPosition(self)
+end
+
+function gamera:setWindow(l,t,w,h)
+  checkAABB(l,t,w,h)
+
+  self.l, self.t, self.w, self.h, self.w2, self.h2 = l,t,w,h, w*0.5, h*0.5
+
+  adjustPosition(self)
+end
+
+function gamera:setPosition(x,y)
+  checkNumber(x, "x")
+  checkNumber(y, "y")
+
+  self.x, self.y = x,y
+
+  adjustPosition(self)
+end
+
+function gamera:setScale(scale)
+  checkNumber(scale, "scale")
+
+  self.scale = scale
+
+  adjustScale(self)
+  adjustPosition(self)
+end
+
+function gamera:setAngle(angle)
+  checkNumber(angle, "angle")
+
+  self.angle = angle
+  self.cos, self.sin = math.cos(angle), math.sin(angle)
+
+  adjustScale(self)
+  adjustPosition(self)
+end
+
+function gamera:getWorld()
+  return self.wl, self.wt, self.ww, self.wh
+end
+
+function gamera:getWindow()
+  return self.l, self.t, self.w, self.h
+end
+
+function gamera:getPosition()
+  return self.x, self.y
+end
+
+function gamera:getScale()
+  return self.scale
+end
+
+function gamera:getAngle()
+  return self.angle
+end
+
+function gamera:getVisible()
+  local w,h = getVisibleArea(self)
+  return self.x - w*0.5, self.y - h*0.5, w, h
+end
+
+function gamera:getVisibleCorners()
+  local x,y,w2,h2 = self.x, self.y, self.w2, self.h2
+
+  local x1,y1 = cornerTransform(self, x-w2,y-h2)
+  local x2,y2 = cornerTransform(self, x+w2,y-h2)
+  local x3,y3 = cornerTransform(self, x+w2,y+h2)
+  local x4,y4 = cornerTransform(self, x-w2,y+h2)
+
+  return x1,y1,x2,y2,x3,y3,x4,y4
+end
+
+-- modified here
+function gamera:apply()
+    love.graphics.setScissor(self:getWindow())
+
+    love.graphics.push()
+    local scale = self.scale
+    love.graphics.scale(scale)
+    love.graphics.translate((self.w2 + self.l) / scale, (self.h2+self.t) / scale)
+    love.graphics.rotate(-self.angle)
+    love.graphics.translate(-self.x, -self.y)
+end
+
+function gamera:remove()
+      love.graphics.pop()
+      love.graphics.setScissor()
+end
+
+function gamera:draw(f)
+    self:apply()
+    f(self:getVisible())
+    self:remove()
+end
+-- to here
+
+function gamera:toWorld(x,y)
+  local scale, sin, cos = self.scale, self.sin, self.cos
+  x,y = (x - self.w2 - self.l) / scale, (y - self.h2 - self.t) / scale
+  x,y = cos*x - sin*y, sin*x + cos*y
+  return x + self.x, y + self.y
+end
+
+function gamera:toScreen(x,y)
+  local scale, sin, cos = self.scale, self.sin, self.cos
+  x,y = x - self.x, y - self.y
+  x,y = cos*x + sin*y, -sin*x + cos*y
+  return scale * x + self.w2 + self.l, scale * y + self.h2 + self.t
+end
+
+return gamera

lib/gamestate.lua

@@ -0,0 +1,93 @@
+--[[
+Copyright (c) 2010-2013 Matthias Richter
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+Except as contained in this notice, the name(s) of the above copyright holders
+shall not be used in advertising or otherwise to promote the sale, use or
+other dealings in this Software without prior written authorization.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+]]--
+
+local function __NULL__() end
+
+ -- default gamestate produces error on every callback
+local state_init = setmetatable({leave = __NULL__},
+		{__index = function() error("Gamestate not initialized. Use Gamestate.switch()") end})
+local stack = {state_init}
+
+local GS = {}
+function GS.new(t) return t or {} end -- constructor - deprecated!
+
+function GS.switch(to, ...)
+	assert(to, "Missing argument: Gamestate to switch to")
+	assert(to ~= GS, "Can't call switch with colon operator")
+	local pre = stack[#stack]
+	;(pre.leave or __NULL__)(pre)
+	;(to.load or __NULL__)(to)
+	to.load = nil
+	stack[#stack] = to
+	return (to.enter or __NULL__)(to, pre, ...)
+end
+
+function GS.push(to, ...)
+	assert(to, "Missing argument: Gamestate to switch to")
+	assert(to ~= GS, "Can't call push with colon operator")
+	local pre = stack[#stack]
+	;(to.load or __NULL__)(to)
+	to.load = nil
+	stack[#stack+1] = to
+	return (to.enter or __NULL__)(to, pre, ...)
+end
+
+function GS.pop(...)
+	assert(#stack > 1, "No more states to pop!")
+	local pre, to = stack[#stack], stack[#stack-1] 
+	stack[#stack] = nil
+	;(pre.leave or __NULL__)(pre)
+	return (to.resume or __NULL__)(to, pre, ...)
+end
+
+function GS.current()
+	return stack[#stack]
+end
+
+local all_callbacks = {
+	'draw', 'errhand', 'focus', 'keypressed', 'keyreleased', 'mousefocus',
+	'mousemoved', 'mousepressed', 'mousereleased', 'quit', 'resize',
+	'textinput', 'threaderror', 'update', 'visible', 'gamepadaxis',
+	'gamepadpressed', 'gamepadreleased', 'joystickadded', 'joystickaxis',
+	'joystickhat', 'joystickpressed', 'joystickreleased', 'joystickremoved'
+}
+
+function GS.registerEvents(callbacks)
+	local registry = {}
+	callbacks = callbacks or all_callbacks
+	for _, f in ipairs(callbacks) do
+		registry[f] = love[f] or __NULL__
+		love[f] = function(...)
+			registry[f](...)
+			return GS[f](...)
+		end
+	end
+end
+
+-- forward any undefined functions
+setmetatable(GS, {__index = function(_, func)
+	return function(...)
+		return (stack[#stack][func] or __NULL__)(stack[#stack], ...)
+	end
+end})
+
+return GS

lib/multisource.lua

@@ -0,0 +1,91 @@
+--[[
+-- multisource lib
+-- A multisource is a wrapper on top of a LÖVE source. It allows
+-- creating multiple sounds easily. It uses an internal pool of
+-- resources.
+-- * multisource:play() finds a stopped resource from the pool,
+--   or creates a new one, and plays and returns it.
+-- * multisouce:cleanup() liberates the memory of old unplayed sources.
+]]
+
+local multisource = {}
+
+local MultiSource   = {}
+local MultiSourceMt = {__index = MultiSource}
+
+function MultiSource:cleanup(older_than)
+  older_than = older_than or 5
+
+  local now = love.timer.getTime()
+
+  for instance, lastPlayed in pairs(self.instances) do
+    local age = now - lastPlayed
+    if age > older_than and instance:isStopped() then
+      self.instances[instance] = nil
+    end
+  end
+end
+
+function MultiSource:getStoppedOrNewInstance()
+  for instance in pairs(self.instances) do
+    if instance:isStopped() then return instance end
+  end
+  return self.source:clone()
+end
+
+function MultiSource:play()
+  local instance = self:getStoppedOrNewInstance()
+  self.instances[instance] = love.timer.getTime()
+
+  instance:play()
+
+  return instance
+end
+
+function MultiSource:stop()
+  for instance in pairs(self.instances) do
+    instance:stop()
+  end
+end
+
+function MultiSource:pause()
+  for instance in pairs(self.instances) do
+    instance:pause()
+  end
+end
+
+function MultiSource:setLooping(looping)
+  self.source:setLooping(looping)
+end
+
+function MultiSource:resume()
+  for instance in pairs(self.instances) do
+    instance:resume()
+  end
+end
+
+function MultiSource:countPlayingInstances()
+  local count = 0
+  for instance in pairs(self.instances) do
+    if instance:isPlaying() then
+      count = count + 1
+    end
+  end
+  return count
+end
+
+function MultiSource:countInstances()
+  local count = 0
+  for instance in pairs(self.instances) do
+    count = count + 1
+  end
+  return count
+end
+
+----
+
+multisource.new = function(source)
+  return setmetatable({source = source, instances = {}}, MultiSourceMt)
+end
+
+return multisource

lib/tiny.lua

@@ -0,0 +1,558 @@
+--- @module tiny-ecs
+-- @author Calvin Rose
+local tiny = { _VERSION = "1.0-2" }
+
+-- Local versions of standard lua functions
+local tinsert = table.insert
+local tremove = table.remove
+local pairs = pairs
+local ipairs = ipairs
+local setmetatable = setmetatable
+local type = type
+
+-- Local versions of the library functions
+local tiny_manageEntities
+local tiny_manageSystems
+local tiny_addEntity
+local tiny_addSystem
+local tiny_add
+local tiny_removeEntity
+local tiny_removeSystem
+local tiny_remove
+
+--- Filter functions.
+-- A Filter is a function that selects which Entities apply to a System.
+-- @section Filter
+
+--- Makes a Filter that filters Entities with specified Components.
+-- An Entity must have all Components to match the filter.
+-- @param ... List of Components
+function tiny.requireAll(...)
+    local components = {...}
+    local len = #components
+    return function(_, e)
+        local c
+        for i = 1, len do
+            c = components[i]
+            if type(c) == 'function' then
+                if not c(_, e) then
+                    return false
+                end
+            elseif e[c] == nil then
+                return false
+            end
+        end
+        return true
+    end
+end
+
+--- Makes a Filter that filters Entities with specified Components.
+-- An Entity must have at least one specified Component to match the filter.
+-- @param ... List of Components
+function tiny.requireOne(...)
+    local components = {...}
+    local len = #components
+    return function(_, e)
+        local c
+        for i = 1, len do
+            c = components[i]
+            if type(c) == 'function' then
+                if c(_, e) then
+                    return true
+                end
+            elseif e[c] ~= nil then
+                return true
+            end
+        end
+        return false
+    end
+end
+
+--- System functions.
+-- A System is a wrapper around function callbacks for manipulating Entities.
+-- @section System
+
+-- Use an empty table as a key for identifying Systems. Any table that contains
+-- this key is considered a System rather than an Entity.
+local systemTableKey = { "SYSTEM_TABLE_KEY" }
+
+-- Check if tables are systems.
+local function isSystem(table)
+    return table[systemTableKey]
+end
+
+--- Creates a System. Systems are tables that contain at least one field; 
+-- an update function that takes parameters like so: 
+-- `function system:update(entities, dt)`. `entities` is an unordered table of 
+-- Entities with Entities as KEYS, and `dt` is the delta time. There are also a 
+-- few other optional callbacks:
+-- `function system:filter(entity)` - returns a boolean,
+-- `function system:onAdd(entity)` - returns nil,
+-- `function system:onRemove(entity)` - returns nil.
+-- For Filters, it is conveient to use `tiny.requireAll` or `tiny.requireOne`,
+-- but one can write their own filters as well.
+-- @param table A table to be used as a System, or `nil` to create a new System.
+function tiny.system(table)
+    if table == nil then
+        table = {}
+    end
+    table[systemTableKey] = true
+    return table
+end
+
+-- Update function for all Processing Systems.
+local function processingSystemUpdate(system, entities, dt)
+    local preProcess = system.preProcess
+    local process = system.process
+    local postProcess = system.postProcess
+    local entity
+
+    if preProcess then
+        preProcess(system, entities, dt)
+    end
+
+    if process then
+        local len = #entities
+        for i = 1, len do
+            entity = entities[i]
+            process(system, entity, dt)
+        end
+    end
+
+    if postProcess then
+        postProcess(system, entities, dt)
+    end
+end
+
+--- Creates a Processing System. A Processing System iterates through its 
+-- Entities in no particluar order, and updates them individually. It has two 
+-- important fields, `function system:process(entity, dt)`, and `function 
+-- system:filter(entity)`. `entities` is Entities, 
+-- and `dt` is the delta time. There are also a few other 
+-- optional callbacks:
+-- `function system:preProcess(entities, dt)` - returns nil,
+-- `function system:postProcess(entities, dt)` - returns nil,
+-- `function system:onAdd(entity)` - returns nil,
+-- `function system:onRemove(entity)` - returns nil.
+-- For Filters, it is conveient to use `tiny.requireAll` or `tiny.requireOne`,
+-- but one can write their own filters as well.
+-- @param table A table to be used as a System, or `nil` to create a new 
+-- Processing System.
+function tiny.processingSystem(table)
+    if table == nil then
+        table = {}
+    end
+    table[systemTableKey] = true
+    table.update = processingSystemUpdate
+    return table
+end
+
+--- World functions.
+-- A World is a container that manages Entities and Systems. The tiny-ecs module
+-- is set to be the `__index` of all World tables, so the often clearer syntax of
+-- World:method can be used for any function in the library. For example,
+-- `tiny.add(world, e1, e2, e3)` is the same as `world:add(e1, e2, e3).`
+-- @section World
+
+local worldMetaTable = { __index = tiny }
+
+--- Creates a new World.
+-- Can optionally add default Systems and Entities.
+-- @param ... Systems and Entities to add to the World
+-- @return A new World
+function tiny.world(...)
+
+    local ret = {
+
+        -- List of Entities to add
+        entitiesToAdd = {},
+
+        -- List of Entities to remove
+        entitiesToRemove = {},
+
+        -- List of Entities to add
+        systemsToAdd = {},
+
+        -- List of Entities to remove
+        systemsToRemove = {},
+
+        -- Set of Entities 
+        entities = {},
+
+        -- Number of Entities in World.
+        entityCount = 0,
+
+        -- List of System Data. A data element is a table with 4
+        -- keys: system, indices, entities, and active.
+        systems = {},
+
+        -- Table of Systems to System Indices
+        systemIndices = {}
+    }
+
+    tiny_add(ret, ...)
+    tiny_manageSystems(ret)
+    tiny_manageEntities(ret)
+
+    return setmetatable(ret, worldMetaTable)
+
+end
+
+--- Adds an Entity to the world.
+-- The new Entity will enter the world next time World:update is called.
+-- Also call this on Entities that have changed Components such that it 
+-- matches different systems.
+-- @param world
+-- @param entity
+function tiny.addEntity(world, entity)
+    local e2a = world.entitiesToAdd
+    e2a[#e2a + 1] = entity
+    if world.entities[entity] then
+        tiny_removeEntity(world, entity)
+    end
+end
+tiny_addEntity = tiny.addEntity
+
+--- Adds a System to the world.
+-- The new System will enter the world next time World:update is called.
+-- @param world
+-- @param system
+function tiny.addSystem(world, system)
+    local s2a = world.systemsToAdd
+    s2a[#s2a + 1] = system
+end
+tiny_addSystem = tiny.addSystem
+
+--- Shortcut for adding multiple Entities and Systems to the World.
+-- New objects will enter the World the next time World:update(dt) is called.
+-- Also call this method when an Entity has had its Components changed, such
+-- that it matches different Filters.
+-- @param world
+-- @param ... Systems and Entities
+function tiny.add(world, ...)
+    local args = {...}
+    for _, obj in ipairs(args) do
+        if isSystem(obj) then
+            tiny_addSystem(world, obj)
+        else -- Assume obj is an Entity
+            tiny_addEntity(world, obj)
+        end
+    end
+end
+tiny_add = tiny.add
+
+--- Removes an Entity to the World.
+-- The Entity will exit the World next time World:update is called.
+-- Also call this on Entities that have changed Components such that it 
+-- matches different systems.
+-- @param world
+-- @param entity
+function tiny.removeEntity(world, entity)
+    local e2r = world.entitiesToRemove
+    e2r[#e2r + 1] = entity
+end
+tiny_removeEntity = tiny.removeEntity
+
+--- Removes a System from the world.
+-- The System will exit the World next time World:update is called.
+-- @param world
+-- @param system
+function tiny.removeSystem(world, system)
+    local s2r = world.systemsToRemove
+    s2r[#s2r + 1] = system
+end
+tiny_removeSystem = tiny.removeSystem
+
+--- Shortcut for removing multiple Entities and Systems from the World. 
+-- Objects will exit the World the next time World:update(dt) is called.
+-- @param world
+-- @param ... Systems and Entities
+function tiny.remove(world, ...)
+    local args = {...}
+    for _, obj in ipairs(args) do
+        if isSystem(obj) then
+            tiny_removeSystem(world, obj)
+        else -- Assume obj is an Entity
+           tiny_removeEntity(world, obj)
+        end
+    end
+end
+tiny_remove = tiny.remove
+
+--- Updates a System.
+-- @param world
+-- @param system A System in the World to update
+-- @param dt Delta time
+function tiny.updateSystem(world, system, dt)
+    local es = world.systemEntities[system]
+    system:update(es, dt)
+end
+
+--- Adds and removes Systems that have been marked from the World.
+-- The user of this library should seldom if ever call this.
+-- @param world
+function tiny.manageSystems(world)
+
+        local s2a, s2r = world.systemsToAdd, world.systemsToRemove
+
+        -- Early exit
+        if #s2a == 0 and #s2r == 0 then
+            return
+        end
+
+        local systemIndices = world.systemIndices
+        local entities = world.entities
+        local systems = world.systems
+
+        local system, systemData, index, filter, entityList, entityIndices, entityIndex, onRemove, onAdd
+
+        -- Remove Systems
+        for i = 1, #s2r do
+            system = s2r[i]
+            index = systemIndices[system]
+            if index then
+                systemData = systems[index]
+                onRemove = system.onRemove
+                if onRemove then
+                    entityList = systemData.entities
+                    for j = 1, #entityList do
+                        onRemove(system, entityList[j])
+                    end
+                end
+                systemIndices[system] = nil
+                tremove(systems, index)
+                for j = index, #systems do
+                    systemIndices[systems[j].system] = j
+                end
+            end
+            s2r[i] = nil
+        end
+
+        -- Add Systems
+        for i = 1, #s2a do
+            system = s2a[i]
+            if not systemIndices[system] then
+                entityList = {}
+                entityIndices = {}
+                systemData = { system = system, entities = entityList, indices = entityIndices, active = true }
+                index = #systems + 1
+                systemIndices[system] = index
+                systems[index] = systemData
+
+                -- Try to add Entities
+                onAdd = system.onAdd
+                filter = system.filter
+                if filter then
+                    for entity in pairs(entities) do
+                        if filter(system, entity) then
+                            entityIndex = #entityList + 1
+                            entityList[entityIndex] = entity
+                            entityIndices[entity] = entityIndex
+                            if onAdd then
+                                onAdd(system, entity)
+                            end
+                        end
+                    end
+                end
+            end
+            s2a[i] = nil
+        end
+
+end
+tiny_manageSystems = tiny.manageSystems
+
+--- Adds and removes Entities that have been marked.
+-- The user of this library should seldom if ever call this.
+-- @param world
+function tiny.manageEntities(world)
+
+    local e2a, e2r = world.entitiesToAdd, world.entitiesToRemove
+
+    -- Early exit
+    if #e2a == 0 and #e2r == 0 then
+        return
+    end
+
+    local entities = world.entities
+    local systems = world.systems
+    local entityCount = world.entityCount
+    local entity, system, systemData, index, onRemove, onAdd, ses, seis, filter, tmpEntity
+
+    -- Remove Entities
+    for i = 1, #e2r do
+        entity = e2r[i]
+        if entities[entity] then
+            entities[entity] = nil
+
+            for j = 1, #systems do
+                systemData = systems[j]
+                system = systemData.system
+                ses = systemData.entities
+                seis = systemData.indices
+                index = seis[entity]
+
+                if index then
+                    tmpEntity = ses[#ses]
+                    ses[index] = tmpEntity
+                    seis[tmpEntity] = index
+                    seis[entity] = nil
+                    ses[#ses] = nil
+                    entityCount = entityCount - 1
+                    onRemove = system.onRemove
+                    if onRemove then
+                        onRemove(system, entity)
+                    end
+                end
+
+            end
+
+        end
+        e2r[i] = nil
+    end
+
+
+    -- Add Entities
+    for i = 1, #e2a do
+        entity = e2a[i]
+        if not entities[entity] then
+            entities[entity] = true
+
+            for j = 1, #systems do
+                systemData = systems[j]
+                system = systemData.system
+                ses = systemData.entities
+                seis = systemData.indices
+                filter = system.filter
+                if filter and filter(system, entity) then
+                    index = #ses + 1
+                    ses[index] = entity
+                    seis[entity] = index
+                    entityCount = entityCount + 1
+                    onAdd = system.onAdd
+                    if onAdd then
+                        onAdd(system, entity)
+                    end
+                end
+
+            end
+
+        end
+        e2a[i] = nil
+    end
+
+    -- Update Entity count
+    world.entityCount = entityCount
+
+end
+tiny_manageEntities = tiny.manageEntities
+
+--- Updates the World.
+-- Frees Entities that have been marked for freeing, adds
+-- entities that have been marked for adding, etc.
+-- @param world
+-- @param dt Delta time
+function tiny.update(world, dt)
+
+    tiny_manageSystems(world)
+    tiny_manageEntities(world)
+
+    local systems = world.systems
+    local systemData
+
+    --  Iterate through Systems IN ORDER
+    for i = 1, #systems do
+        systemData = systems[i]
+        if systemData.active then
+            systemData.system:update(systemData.entities, dt)
+        end
+    end
+end
+
+--- Removes all Entities from the World.
+-- When World:update(dt) is next called,
+-- all Entities will be removed.
+-- @param world
+function tiny.clearEntities(world)
+    for e in pairs(world.entities) do
+        tiny_removeEntity(world, e)
+    end
+end
+
+--- Removes all Systems from the World.
+-- When World:update(dt) is next called,
+-- all Systems will be removed.
+-- @param world
+function tiny.clearSystems(world)
+    local systems = world.systems
+    for i = #systems, 1, -1 do
+        tiny_removeSystem(world, systems[i].system)
+    end
+end
+
+--- Gets count of Entities in World.
+-- @param world
+function tiny.getEntityCount(world)
+    return world.entityCount
+end
+
+--- Gets count of Systems in World.
+-- @param world
+function tiny.getSystemCount(world)
+    return #(world.systems)
+end
+
+--- Gets the index of a System in the world. Lower indexed Systems are processed
+-- before higher indexed systems.
+-- @param world
+-- @param system
+function tiny.getSystemIndex(world, system)
+    return world.systemIndices[system]
+end
+
+--- Sets the index of a System in the world. Changes the order in
+-- which they Systems processed, because lower indexed Systems are processed 
+-- first.
+-- @param world
+-- @param system
+-- @param index
+function tiny.setSystemIndex(world, system, index)
+    local systemIndices = world.systemIndices
+    local oldIndex = systemIndices[system]
+    local systems = world.systems
+    local systemData = systems[oldIndex]
+
+    tremove(systems, oldIndex)
+    tinsert(systems, index, systemData)
+
+    for i = oldIndex, index, index >= oldIndex and 1 or -1 do
+        systemIndices[systems[i].system] = i
+    end
+end
+
+--- Activates Systems in the World.
+-- Activated Systems will be update whenever tiny.update(world, dt) is called.
+-- @param world
+-- @param ... Systems to activate. The Systems must already be added to the
+-- World.
+function tiny.activate(world, ...)
+    local args = {...}
+    for _, system in ipairs(args) do
+        world.systems[world.systemIndices[system]].active = true
+    end
+end
+
+--- Deactivates Systems in the World.
+-- Deactivated Systems must be update manually, and will not update when the
+-- rest of World updates. They will, however, process new Entities added while
+-- the System is deactivated.
+-- @param world
+-- @param ... Systems to deactivate. The Systems must already be added to the
+-- World.
+function tiny.deactivate(world, ...)
+    local args = {...}
+    for _, system in ipairs(args) do
+        world.systems[world.systemIndices[system]].active = false
+    end
+end
+
+return tiny