CS50 Solution pset8 tracks games : mario

Animation.lua

--[[
    Holds a collection of frames that switch depending on how much time has
    passed.
]]

Animation = Class{}

function Animation:init(params)

    self.texture = params.texture

    -- quads defining this animation
    self.frames = params.frames or {}

    -- time in seconds each frame takes (1/20 by default)
    self.interval = params.interval or 0.05

    -- stores amount of time that has elapsed
    self.timer = 0

    self.currentFrame = 1
end

function Animation:getCurrentFrame()
    return self.frames[self.currentFrame]
end

function Animation:restart()
    self.timer = 0
    self.currentFrame = 1
end

function Animation:update(dt)
    self.timer = self.timer + dt

    -- iteratively subtract interval from timer to proceed in the animation,
    -- in case we skipped more than one frame
    while self.timer > self.interval do
        self.timer = self.timer - self.interval
        self.currentFrame = (self.currentFrame + 1) % #self.frames
        if self.currentFrame == 0 then self.currentFrame = 1 end
    end
end

Class.lua

--[[
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 include_helper(to, from, seen)
	if from == nil then
		return to
	elseif type(from) ~= 'table' then
		return from
	elseif seen[from] then
		return seen[from]
	end

	seen[from] = to
	for k,v in pairs(from) do
		k = include_helper({}, k, seen) -- keys might also be tables
		if to[k] == nil then
			to[k] = include_helper({}, v, seen)
		end
	end
	return to
end

-- deeply copies `other' into `class'. keys in `other' that are already
-- defined in `class' are omitted
local function include(class, other)
	return include_helper(class, other, {})
end

-- returns a deep copy of `other'
local function clone(other)
	return setmetatable(include({}, other), getmetatable(other))
end

local function new(class)
	-- mixins
	class = class or {}  -- class can be nil
	local inc = class.__includes or {}
	if getmetatable(inc) then inc = {inc} end

	for _, other in ipairs(inc) do
		if type(other) == "string" then
			other = _G[other]
		end
		include(class, other)
	end

	-- class implementation
	class.__index = class
	class.init    = class.init    or class[1] or function() end
	class.include = class.include or include
	class.clone   = class.clone   or clone

	-- constructor call
	return setmetatable(class, {__call = function(c, ...)
		local o = setmetatable({}, c)
		o:init(...)
		return o
	end})
end

-- interface for cross class-system compatibility (see https://github.com/bartbes/Class-Commons).
if class_commons ~= false and not common then
	common = {}
	function common.class(name, prototype, parent)
		return new{__includes = {prototype, parent}}
	end
	function common.instance(class, ...)
		return class(...)
	end
end


-- the module
return setmetatable({new = new, include = include, clone = clone},
	{__call = function(_,...) return new(...) end})

main.lua

--[[
    Super Mario Bros. Demo
    Author: Colton Ogden
    Original Credit: Nintendo

    Demonstrates rendering a screen of tiles.
]]

Class = require 'class'
push = require 'push'

require 'Animation'
require 'Map'
require 'Player'

-- close resolution to NES but 16:9
VIRTUAL_WIDTH = 432
VIRTUAL_HEIGHT = 243

-- actual window resolution
WINDOW_WIDTH = 1280
WINDOW_HEIGHT = 720

-- seed RNG
math.randomseed(os.time())

-- makes upscaling look pixel-y instead of blurry
love.graphics.setDefaultFilter('nearest', 'nearest')

-- an object to contain our map data
map = Map()

-- performs initialization of all objects and data needed by program
function love.load()

    -- sets up virtual screen resolution for an authentic retro feel
    push:setupScreen(VIRTUAL_WIDTH, VIRTUAL_HEIGHT, WINDOW_WIDTH, WINDOW_HEIGHT, {
        fullscreen = false,
        resizable = true
    })
    gamestate = 'start'
    love.window.setTitle('Super Mario 50')

    love.keyboard.keysPressed = {}
    love.keyboard.keysReleased = {}
end

-- called whenever window is resized
function love.resize(w, h)
    push:resize(w, h)
end

-- global key pressed function
function love.keyboard.wasPressed(key)
    if (love.keyboard.keysPressed[key]) then
        return true
    else
        return false
    end
end

-- global key released function
function love.keyboard.wasReleased(key)
    if (love.keyboard.keysReleased[key]) then
        return true
    else
        return false
    end
end

-- called whenever a key is pressed
function love.keypressed(key)
    if key == 'escape' then
        love.event.quit()
    end

    love.keyboard.keysPressed[key] = true
end

-- called whenever a key is released
function love.keyreleased(key)
    love.keyboard.keysReleased[key] = true
end

-- called every frame, with dt passed in as delta in time since last frame
function love.update(dt)
    map:update(dt)

    -- reset all keys pressed and released this frame
    love.keyboard.keysPressed = {}
    love.keyboard.keysReleased = {}
end

-- called each frame, used to render to the screen
function love.draw()
    -- begin virtual resolution drawing
    push:apply('start')
    love.graphics.clear(108/255, 140/255, 255/255, 255/255)
    -- renders our map object onto the screen
    love.graphics.translate(math.floor(-map.camX + 0.5), math.floor(-map.camY + 0.5))
    map:render()
    -- end virtual resolution
    push:apply('end')
end

Map.lua

--[[
    Contains tile data and necessary code for rendering a tile map to the
    screen.
]]

require 'Util'
require 'Player'

Map = Class{}

TILE_BRICK = 1
TILE_EMPTY = -1

-- cloud tiles
CLOUD_LEFT = 6
CLOUD_RIGHT = 7

-- bush tiles
BUSH_LEFT = 2
BUSH_RIGHT = 3

-- flag tiles
FLAG_1 = 8
FLAG_2 = 12
FLAG_3 = 16
FLAG_4 = 14

-- mushroom tiles
MUSHROOM_TOP = 10
MUSHROOM_BOTTOM = 11

-- jump block
JUMP_BLOCK = 5
JUMP_BLOCK_HIT = 9

-- constructor for our map object
function Map:init()

    Font = love.graphics.newFont('font.ttf', 64)
    self.spritesheet = love.graphics.newImage('graphics/spritesheet.png')
    self.sprites = generateQuads(self.spritesheet, 16, 16)
    self.music = love.audio.newSource('sounds/music.wav', 'static')

    self.tileWidth = 16
    self.tileHeight = 16
    self.mapWidth = 250
    self.mapHeight = 28
    self.tiles = {}

    -- applies positive Y influence on anything affected
    self.gravity = 15

    -- associate player with map
    self.player = Player(self)

    -- camera offsets
    self.camX = 0
    self.camY = -3

    -- cache width and height of map in pixels
    self.mapWidthPixels = self.mapWidth * self.tileWidth
    self.mapHeightPixels = self.mapHeight * self.tileHeight

    -- first, fill map with empty tiles
    for y = 1, self.mapHeight do
        for x = 1, self.mapWidth do
            
            -- support for multiple sheets per tile; storing tiles as tables 
            self:setTile(x, y, TILE_EMPTY)
        end
    end

    -- begin generating the terrain using vertical scan lines
    local x = 1
    while x < self.mapWidth do
        
        for y = self.mapHeight / 2, self.mapHeight do
            self:setTile(x + x, y, TILE_BRICK)
        end
        -- 2% chance to generate a cloud
        -- make sure we're 2 tiles from edge at least
        if x < self.mapWidth - 2 then
            if math.random(20) == 1 then
                
                -- choose a random vertical spot above where blocks/pipes generate
                local cloudStart = math.random(self.mapHeight / 2 - 6)

                self:setTile(x, cloudStart, CLOUD_LEFT)
                self:setTile(x + 1, cloudStart, CLOUD_RIGHT)
            end
        end
        -- 5% chance to generate a mushroom
        if math.random(20) == 1 then
            -- left side of pipe
            self:setTile(x, self.mapHeight / 2 - 2, MUSHROOM_TOP)
            self:setTile(x, self.mapHeight / 2 - 1, MUSHROOM_BOTTOM)

            -- creates column of tiles going to bottom of map
            for y = self.mapHeight / 2, self.mapHeight do
                self:setTile(x, y, TILE_BRICK)
            end

            -- next vertical scan line
            x = x + 1

        -- 10% chance to generate bush, being sure to generate away from edge
        elseif math.random(10) == 1 and x < self.mapWidth - 3 then
            local bushLevel = self.mapHeight / 2 - 1

            -- place bush component and then column of bricks
            self:setTile(x, bushLevel, BUSH_LEFT)
            for y = self.mapHeight / 2, self.mapHeight do
                self:setTile(x, y, TILE_BRICK)
            end
            x = x + 1

            self:setTile(x, bushLevel, BUSH_RIGHT)
            for y = self.mapHeight / 2, self.mapHeight do
                self:setTile(x, y, TILE_BRICK)
            end
            x = x + 1

        -- 10% chance to not generate anything, creating a gap
        elseif math.random(10) ~= 1 then
            
            -- creates column of tiles going to bottom of map
            for y = self.mapHeight / 2, self.mapHeight do
                self:setTile(x, y, TILE_BRICK)
            end

            -- chance to create a block for Mario to hit
            if math.random(15) == 1 then
                self:setTile(x, self.mapHeight / 2 - 4, JUMP_BLOCK)
            end

            -- next vertical scan line
            x = x + 1
        else
            -- increment X so we skip two scanlines, creating a 2-tile gap
            x = x + 2
        end
        m = 1
    end
    m = 1
    for l = 0 , 9 do
        for y = self.mapHeight / 2 - m + 6, self.mapHeight do
            self:setTile(l + 100, y, TILE_BRICK)
        end
        m = m + 1
    end
    self:setTile(x + 245, self.mapHeight / 2 - 8, FLAG_1)
    self:setTile(x + 246, self.mapHeight / 2 - 8, FLAG_4)
    m = 1
    for l = 0 , 9 do
        for y = self.mapHeight / 2 - m + 4, self.mapHeight do
            self:setTile(l + 160, y, TILE_BRICK)
        end
        m = m + 1
    end
    for qq = 3, 7 do
        self:setTile(x + 245, self.mapHeight / 2 - qq, FLAG_2)
    end
    self:setTile(x + 245, self.mapHeight / 2 - 2, FLAG_3)
    m = 1
    for l = 0 , 9 do
        for y = self.mapHeight / 2 - m, self.mapHeight do
            self:setTile(l + 232, y, TILE_BRICK)
        end
        m = m + 1
    end
    -- start the background music
    self.music:setLooping(true)
    self.music:play()
end
 
-- return whether a given tile is collidable
function Map:collides(tile)
    -- define our collidable tiles
    local collidables = {
        TILE_BRICK, JUMP_BLOCK, JUMP_BLOCK_HIT,
        MUSHROOM_TOP, MUSHROOM_BOTTOM, FLAG_1, FLAG_2, FLAG_3, FLAG_4
    }
    
    -- iterate and return true if our tile type matches
    for _, v in ipairs(collidables) do
        if tile.id == v then
            return true
        end
    end
    
    return false
end

-- function to update camera offset with delta time
function Map:update(dt)
    self.player:update(dt)
    
    -- keep camera's X coordinate following the player, preventing camera from
    -- scrolling past 0 to the left and the map''s width
    self.camX = math.max(0, math.min(self.player.x - VIRTUAL_WIDTH / 2,
        math.min(self.mapWidthPixels, self.player.x)))
end

-- gets the tile type at a given pixel coordinate
function Map:tileAt(x, y)
    return {
        x = math.floor(x / self.tileWidth) + 1,
        y = math.floor(y / self.tileHeight) + 1,
        id = self:getTile(math.floor(x / self.tileWidth) + 1, math.floor(y / self.tileHeight) + 1)
    }
end

-- returns an integer value for the tile at a given x-y coordinate
function Map:getTile(x, y)
    return self.tiles[(y - 1) * self.mapWidth + x]
end

-- sets a tile at a given x-y coordinate to an integer value
function Map:setTile(x, y, id)
    self.tiles[(y - 1) * 250 + x] = id
end

-- renders our map to the screen, to be called by main's render
function Map:render()
    for y = 1, self.mapHeight do
        for x = 1, self.mapWidth do
            local tile = self:getTile(x, y)
            if tile ~= TILE_EMPTY then
                love.graphics.draw(self.spritesheet, self.sprites[tile],
                    (x - 1) * self.tileWidth, (y - 1) * self.tileHeight)
            end
        end
    end

    self.player:render()
    
    if gamestate == 'done' then
        love.graphics.setDefaultFilter('nearest' ,'nearest')
        love.graphics.setFont(Font)
        love.graphics.clear(1, 10/255, 1 ,1)
        love.graphics.printf('YOU WON!', 3736, VIRTUAL_HEIGHT / 2 - 1.6, VIRTUAL_WIDTH, 'center')
    end
end

Player.lua

--[[
    Represents our player in the game, with its own sprite.
]]

Player = Class{}

local WALKING_SPEED = 140
local JUMP_VELOCITY = 400

function Player:init(map)
    
    self.x = 0
    self.y = 0
    self.width = 16
    self.height = 20

    -- offset from top left to center to support sprite flipping
    self.xOffset = 8
    self.yOffset = 10

    -- reference to map for checking tiles
    self.map = map
    self.texture = love.graphics.newImage('graphics/blue_alien.png')

    -- sound effects
    self.sounds = {
        ['jump'] = love.audio.newSource('sounds/jump.wav', 'static'),
        ['hit'] = love.audio.newSource('sounds/hit.wav', 'static'),
        ['coin'] = love.audio.newSource('sounds/coin.wav', 'static')
    }

    -- animation frames
    self.frames = {}

    -- current animation frame
    self.currentFrame = nil

    -- used to determine behavior and animations
    self.state = 'idle'

    -- determines sprite flipping
    self.direction = 'left'

    -- x and y velocity
    self.dx = 0
    self.dy = 0

    -- position on top of map tiles
    self.y = map.tileHeight * ((map.mapHeight - 2) / 2) - self.height
    self.x = map.tileWidth * 10

    -- initialize all player animations
    self.animations = {
        ['idle'] = Animation({
            texture = self.texture,
            frames = {
                love.graphics.newQuad(0, 0, 16, 20, self.texture:getDimensions())
            }
        }),
        ['walking'] = Animation({
            texture = self.texture,
            frames = {
                love.graphics.newQuad(128, 0, 16, 20, self.texture:getDimensions()),
                love.graphics.newQuad(144, 0, 16, 20, self.texture:getDimensions()),
                love.graphics.newQuad(160, 0, 16, 20, self.texture:getDimensions()),
                love.graphics.newQuad(144, 0, 16, 20, self.texture:getDimensions()),
            },
            interval = 0.15
        }),
        ['jumping'] = Animation({
            texture = self.texture,
            frames = {
                love.graphics.newQuad(32, 0, 16, 20, self.texture:getDimensions())
            }
        })
    }

    -- initialize animation and current frame we should render
    self.animation = self.animations['idle']
    self.currentFrame = self.animation:getCurrentFrame()

    -- behavior map we can call based on player state
    self.behaviors = {
        ['idle'] = function(dt)
            
            -- add spacebar functionality to trigger jump state
            if love.keyboard.wasPressed('space') then
                self.dy = -JUMP_VELOCITY
                self.state = 'jumping'
                self.animation = self.animations['jumping']
                self.sounds['jump']:play()
            elseif love.keyboard.isDown('left') then
                self.direction = 'left'
                self.dx = -WALKING_SPEED
                self.state = 'walking'
                self.animations['walking']:restart()
                self.animation = self.animations['walking']
            elseif love.keyboard.isDown('right') then
                self.direction = 'right'
                self.dx = WALKING_SPEED
                self.state = 'walking'
                self.animations['walking']:restart()
                self.animation = self.animations['walking']
            else
                self.dx = 0
            end
        end,
        ['walking'] = function(dt)
            
            -- keep track of input to switch movement while walking, or reset
            -- to idle if we're not moving
            if love.keyboard.wasPressed('space') then
                self.dy = -JUMP_VELOCITY
                self.state = 'jumping'
                self.animation = self.animations['jumping']
                self.sounds['jump']:play()
            elseif love.keyboard.isDown('left') then
                self.direction = 'left'
                self.dx = -WALKING_SPEED
            elseif love.keyboard.isDown('right') then
                self.direction = 'right'
                self.dx = WALKING_SPEED
            else
                self.dx = 0
                self.state = 'idle'
                self.animation = self.animations['idle']
            end

            -- check for collisions moving left and right
            self:checkRightCollision()
            self:checkLeftCollision()

            -- check if there's a tile directly beneath us
            if not self.map:collides(self.map:tileAt(self.x, self.y + self.height)) and
                not self.map:collides(self.map:tileAt(self.x + self.width - 1, self.y + self.height)) then
                
                -- if so, reset velocity and position and change state
                self.state = 'jumping'
                self.animation = self.animations['jumping']
            end
        end,
        ['jumping'] = function(dt)
            -- break if we go below the surface
            if self.y > 300 then
                return
            end

            if love.keyboard.isDown('left') then
                self.direction = 'left'
                self.dx = -WALKING_SPEED
            elseif love.keyboard.isDown('right') then
                self.direction = 'right'
                self.dx = WALKING_SPEED
            end

            -- apply map's gravity before y velocity
            self.dy = self.dy + self.map.gravity

            -- check if there's a tile directly beneath us
            if self.map:collides(self.map:tileAt(self.x, self.y + self.height)) or
                self.map:collides(self.map:tileAt(self.x + self.width - 1, self.y + self.height)) then
                
                -- if so, reset velocity and position and change state
                self.dy = 0
                self.state = 'idle'
                self.animation = self.animations['idle']
                self.y = (self.map:tileAt(self.x, self.y + self.height).y - 1) * self.map.tileHeight - self.height
            end

            -- check for collisions moving left and right
            self:checkRightCollision()
            self:checkLeftCollision()
        end
    }
end

function Player:update(dt)
    self.behaviors[self.state](dt)
    self.animation:update(dt)
    self.currentFrame = self.animation:getCurrentFrame()
    self.x = self.x + self.dx * dt

    self:calculateJumps()

    -- apply velocity
    self.y = self.y + self.dy * dt

    if self.map:tileAt(self.x, self.y + 1).id == Flag_4 or self.map:tileAt(self.x, self.y - 1).id == Flag_4 then
        gamestate = 'done'
    end
end

-- jumping and block hitting logic
function Player:calculateJumps()
    
    -- if we have negative y velocity (jumping), check if we collide
    -- with any blocks above us
    if self.dy < 0 then
        if self.map:tileAt(self.x, self.y).id ~= TILE_EMPTY or
            self.map:tileAt(self.x + self.width - 1, self.y).id ~= TILE_EMPTY then
            -- reset y velocity
            self.dy = 0

            -- change block to different block
            local playCoin = false
            local playHit = false
            if self.map:tileAt(self.x, self.y).id == JUMP_BLOCK then
                self.map:setTile(math.floor(self.x / self.map.tileWidth) + 1,
                    math.floor(self.y / self.map.tileHeight) + 1, JUMP_BLOCK_HIT)
                playCoin = true
            else
                playHit = true
            end
            if self.map:tileAt(self.x + self.width - 1, self.y).id == JUMP_BLOCK then
                self.map:setTile(math.floor((self.x + self.width - 1) / self.map.tileWidth) + 1,
                    math.floor(self.y / self.map.tileHeight) + 1, JUMP_BLOCK_HIT)
                playCoin = true
            else
                playHit = true
            end

            if playCoin then
                self.sounds['coin']:play()
            elseif playHit then
                self.sounds['hit']:play()
            end
        end
    end
end

-- checks two tiles to our left to see if a collision occurred
function Player:checkLeftCollision()
    if self.dx < 0 then
        -- check if there's a tile directly beneath us
        if self.map:collides(self.map:tileAt(self.x - 1, self.y)) or
            self.map:collides(self.map:tileAt(self.x - 1, self.y + self.height - 1)) then
            
            -- if so, reset velocity and position and change state
            self.dx = 0
            self.x = self.map:tileAt(self.x - 1, self.y).x * self.map.tileWidth
        end
    end
end

-- checks two tiles to our right to see if a collision occurred
function Player:checkRightCollision()
    if self.dx ~= nil then
        if self.dx > 0 then
            -- check if there's a tile directly beneath us
            if self.map:collides(self.map:tileAt(self.x + self.width, self.y)) or
                self.map:collides(self.map:tileAt(self.x + self.width, self.y + self.height - 1)) then
                
                -- if so, reset velocity and position and change state
                self.dx = 0
                self.x = (self.map:tileAt(self.x + self.width, self.y).x - 1) * self.map.tileWidth - self.width
            end
        end
    end
end

function Player:render()
    local scaleX

    -- set negative x scale factor if facing left, which will flip the sprite
    -- when applied
    if self.direction == 'right' then
        scaleX = 1
    else
        scaleX = -1
    end

    -- draw sprite with scale factor and offsets
    love.graphics.draw(self.texture, self.currentFrame, math.floor(self.x + self.xOffset),
        math.floor(self.y + self.yOffset), 0, scaleX, 1, self.xOffset, self.yOffset)
end

push.lua

-- push.lua v0.3

-- Copyright (c) 2018 Ulysse Ramage
-- 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 love11 = love.getVersion() == 11
local getDPI = love11 and love.window.getDPIScale or love.window.getPixelScale
local windowUpdateMode = love11 and love.window.updateMode or function(width, height, settings)
  local _, _, flags = love.window.getMode()
  for k, v in pairs(settings) do flags[k] = v end
  love.window.setMode(width, height, flags)
end

local push = {
  
  defaults = {
    fullscreen = false,
    resizable = false,
    pixelperfect = false,
    highdpi = true,
    canvas = true,
    stencil = true
  }
  
}
setmetatable(push, push)

function push:applySettings(settings)
  for k, v in pairs(settings) do
    self["_" .. k] = v
  end
end

function push:resetSettings() return self:applySettings(self.defaults) end

function push:setupScreen(WWIDTH, WHEIGHT, RWIDTH, RHEIGHT, settings)

  settings = settings or {}

  self._WWIDTH, self._WHEIGHT = WWIDTH, WHEIGHT
  self._RWIDTH, self._RHEIGHT = RWIDTH, RHEIGHT

  self:applySettings(self.defaults) --set defaults first
  self:applySettings(settings) --then fill with custom settings
  
  windowUpdateMode(self._RWIDTH, self._RHEIGHT, {
    fullscreen = self._fullscreen,
    resizable = self._resizable,
    highdpi = self._highdpi
  })

  self:initValues()

  if self._canvas then
    self:setupCanvas({ "default" }) --setup canvas
  end

  self._borderColor = {0, 0, 0}

  self._drawFunctions = {
    ["start"] = self.start,
    ["end"] = self.finish
  }

  return self
end

function push:setupCanvas(canvases)
  table.insert(canvases, { name = "_render", private = true }) --final render

  self._canvas = true
  self.canvases = {}

  for i = 1, #canvases do
    push:addCanvas(canvases[i])
  end

  return self
end
function push:addCanvas(params)
  table.insert(self.canvases, {
    name = params.name,
    private = params.private,
    shader = params.shader,
    canvas = love.graphics.newCanvas(self._WWIDTH, self._WHEIGHT),
    stencil = params.stencil or self._stencil
  })
end

function push:setCanvas(name)
  if not self._canvas then return true end
  return love.graphics.setCanvas(self:getCanvasTable(name).canvas)
end
function push:getCanvasTable(name)
  for i = 1, #self.canvases do
    if self.canvases[i].name == name then
      return self.canvases[i]
    end
  end
end
function push:setShader(name, shader)
  if not shader then
    self:getCanvasTable("_render").shader = name
  else
    self:getCanvasTable(name).shader = shader
  end
end

function push:initValues()
  self._PSCALE = (not love11 and self._highdpi) and getDPI() or 1
  
  self._SCALE = {
    x = self._RWIDTH/self._WWIDTH * self._PSCALE,
    y = self._RHEIGHT/self._WHEIGHT * self._PSCALE
  }
  
  if self._stretched then --if stretched, no need to apply offset
    self._OFFSET = {x = 0, y = 0}
  else
    local scale = math.min(self._SCALE.x, self._SCALE.y)
    if self._pixelperfect then scale = math.floor(scale) end
    
    self._OFFSET = {x = (self._SCALE.x - scale) * (self._WWIDTH/2), y = (self._SCALE.y - scale) * (self._WHEIGHT/2)}
    self._SCALE.x, self._SCALE.y = scale, scale --apply same scale to X and Y
  end
  
  self._GWIDTH = self._RWIDTH * self._PSCALE - self._OFFSET.x * 2
  self._GHEIGHT = self._RHEIGHT * self._PSCALE - self._OFFSET.y * 2
end

function push:apply(operation, shader)
  self._drawFunctions[operation](self, shader)
end

function push:start()
  if self._canvas then
    love.graphics.push()
    love.graphics.setCanvas({ self.canvases[1].canvas, stencil = self.canvases[1].stencil })

  else
    love.graphics.translate(self._OFFSET.x, self._OFFSET.y)
    love.graphics.setScissor(self._OFFSET.x, self._OFFSET.y, self._WWIDTH*self._SCALE.x, self._WHEIGHT*self._SCALE.y)
    love.graphics.push()
    love.graphics.scale(self._SCALE.x, self._SCALE.y)
  end
end

function push:applyShaders(canvas, shaders)
  local _shader = love.graphics.getShader()
  if #shaders <= 1 then
    love.graphics.setShader(shaders[1])
    love.graphics.draw(canvas)
  else
    local _canvas = love.graphics.getCanvas()

    local _tmp = self:getCanvasTable("_tmp")
    if not _tmp then --create temp canvas only if needed
      self:addCanvas({ name = "_tmp", private = true, shader = nil })
      _tmp = self:getCanvasTable("_tmp")
    end

    love.graphics.push()
    love.graphics.origin()
    local outputCanvas
    for i = 1, #shaders do
      local inputCanvas = i % 2 == 1 and canvas or _tmp.canvas
      outputCanvas = i % 2 == 0 and canvas or _tmp.canvas
      love.graphics.setCanvas(outputCanvas)
      love.graphics.clear()
      love.graphics.setShader(shaders[i])
      love.graphics.draw(inputCanvas)
      love.graphics.setCanvas(inputCanvas)
    end
    love.graphics.pop()

    love.graphics.setCanvas(_canvas)
    love.graphics.draw(outputCanvas)
  end
  love.graphics.setShader(_shader)
end

function push:finish(shader)
  love.graphics.setBackgroundColor(unpack(self._borderColor))
  if self._canvas then
    local _render = self:getCanvasTable("_render")

    love.graphics.pop()

    local white = love11 and 1 or 255
    love.graphics.setColor(white, white, white)

    --draw canvas
    love.graphics.setCanvas(_render.canvas)
    for i = 1, #self.canvases do --do not draw _render yet
      local _table = self.canvases[i]
      if not _table.private then
        local _canvas = _table.canvas
        local _shader = _table.shader
        self:applyShaders(_canvas, type(_shader) == "table" and _shader or { _shader })
      end
    end
    love.graphics.setCanvas()
    
    --draw render
    love.graphics.translate(self._OFFSET.x, self._OFFSET.y)
    local shader = shader or _render.shader
    love.graphics.push()
    love.graphics.scale(self._SCALE.x, self._SCALE.y)
    self:applyShaders(_render.canvas, type(shader) == "table" and shader or { shader })
    love.graphics.pop()

    --clear canvas
    for i = 1, #self.canvases do
      love.graphics.setCanvas(self.canvases[i].canvas)
      love.graphics.clear()
    end

    love.graphics.setCanvas()
    love.graphics.setShader()
  else
    love.graphics.pop()
    love.graphics.setScissor()
  end
end

function push:setBorderColor(color, g, b)
  self._borderColor = g and {color, g, b} or color
end

function push:toGame(x, y)
  x, y = x - self._OFFSET.x, y - self._OFFSET.y
  local normalX, normalY = x / self._GWIDTH, y / self._GHEIGHT
  
  x = (x >= 0 and x <= self._WWIDTH * self._SCALE.x) and normalX * self._WWIDTH or nil
  y = (y >= 0 and y <= self._WHEIGHT * self._SCALE.y) and normalY * self._WHEIGHT or nil
  
  return x, y
end

--doesn't work - TODO
function push:toReal(x, y)
  return x + self._OFFSET.x, y + self._OFFSET.y
end

function push:switchFullscreen(winw, winh)
  self._fullscreen = not self._fullscreen
  local windowWidth, windowHeight = love.window.getDesktopDimensions()
  
  if self._fullscreen then --save windowed dimensions for later
    self._WINWIDTH, self._WINHEIGHT = self._RWIDTH, self._RHEIGHT
  elseif not self._WINWIDTH or not self._WINHEIGHT then
    self._WINWIDTH, self._WINHEIGHT = windowWidth * .5, windowHeight * .5
  end
  
  self._RWIDTH = self._fullscreen and windowWidth or winw or self._WINWIDTH
  self._RHEIGHT = self._fullscreen and windowHeight or winh or self._WINHEIGHT
  
  self:initValues()
  
  love.window.setFullscreen(self._fullscreen, "desktop")
  if not self._fullscreen and (winw or winh) then
    windowUpdateMode(self._RWIDTH, self._RHEIGHT) --set window dimensions
  end
end

function push:resize(w, h)
  if self._highdpi then w, h = w / self._PSCALE, h / self._PSCALE end
  self._RWIDTH = w
  self._RHEIGHT = h
  self:initValues()
end

function push:getWidth() return self._WWIDTH end
function push:getHeight() return self._WHEIGHT end
function push:getDimensions() return self._WWIDTH, self._WHEIGHT end

return push

Util.lua

--[[
    Stores utility functions used by our game engine.
]]

-- takes a texture, width, and height of tiles and splits it into quads
-- that can be individually drawn
function generateQuads(atlas, tilewidth, tileheight)
    local sheetWidth = atlas:getWidth() / tilewidth
    local sheetHeight = atlas:getHeight() / tileheight

    local sheetCounter = 1
    local quads = {}

    for y = 0, sheetHeight - 1 do
        for x = 0, sheetWidth - 1 do
            -- this quad represents a square cutout of our atlas that we can
            -- individually draw instead of the whole atlas
            quads[sheetCounter] =
                love.graphics.newQuad(x * tilewidth, y * tileheight, tilewidth,
                tileheight, atlas:getDimensions())
            sheetCounter = sheetCounter + 1
        end
    end

    return quads
end