Game window can be resized in the menu (and in the game, but the ground won't resize)

conf.lua

@@ -3,9 +3,9 @@ require 'settings'
 
 function love.conf(t)
     t.window.title = "Fysplane"
-    t.window.width = WIDTH
-    t.window.height = HEIGHT
-    t.window.resizable = false
+    t.window.width = INITIAL_WIDTH
+    t.window.height = INITIAL_HEIGHT
+    t.window.resizable = true
     t.window.vsync = true
 
     -- LÖVE version

entities/ground.lua

@@ -1,5 +1,6 @@
 Class = require 'hump.class'
 require 'entities/rectangle'
+require 'utils'
 
 Ground = Class{
     __includes = Rectangle,
@@ -7,10 +8,15 @@ Ground = Class{
     init = function(self, level)
         local groundImg = love.graphics.newImage('resources/graphics/ground.png')
         Rectangle.init(self,
-		       (love.window.getWidth() - 1600) / 2, love.window.getHeight(),
+		       -200, levelHeight(),
 		       level, "static",
-		       0, 1600, 20, 0, groundImg)
+		       0,
+		       levelWidth() + 400, 20, 0, groundImg)
 	self.fixture:setRestitution(0)
 	self.fixture:setFriction(0.5)
     end;
+
+    update = function(self, dt)
+	self.body:setY(levelHeight() - 10)
+    end;
 }

level.lua

@@ -19,12 +19,8 @@ Level = Class{
         self.world = love.physics.newWorld(GRAVITY_X, GRAVITY_Y, true)
 
         -- Draw background  to canvas so we don't redraw it every time
-        self.background = love.graphics.newImage('resources/graphics/sky.png')
-        self.bgCanvas = love.graphics.newCanvas()
-        love.graphics.setCanvas(self.bgCanvas)
-	love.graphics.setColor(255, 255, 255, 255)
-        love.graphics.draw(self.background)
-        love.graphics.setCanvas()
+	self.oldWidth, self.oldHeight = 0, 0
+	self:updateBackground()
 
         self.makePlanes = { [1] = function()
                                 return Plane(100, 400, INITIAL_PLANE_SPEED, 0,
@@ -32,16 +28,33 @@ Level = Class{
 					     self)
                              end,
                             [2] = function()
-                                return Plane(WIDTH - 100 - 100, 300, -INITIAL_PLANE_SPEED, 0,
+                                return Plane(levelWidth() - 100 - 100, 300, -INITIAL_PLANE_SPEED, 0,
 					     0, 255, 0, -- green
 					     self)
                             end }
 
         self.planes = { [1] = self.makePlanes[1](),
                         [2] = self.makePlanes[2]() }
+
 	Ground(self);
     end;
 
+    updateBackground = function(self)
+	local w, h = levelWidth(), levelHeight()
+	if w ~= self.oldWidth or h ~= self.oldHeight then
+	    local background = love.graphics.newImage('resources/graphics/sky.png')
+	    self.bgCanvas = love.graphics.newCanvas()
+	    love.graphics.setCanvas(self.bgCanvas)
+	    love.graphics.setColor(255, 255, 255, 255)
+	    love.graphics.draw(background, 0, 0, 0,
+			       levelWidth() / background:getWidth(),
+			       levelHeight() / background:getHeight())
+	    love.graphics.setCanvas()
+	    
+	    self.oldWidth, self.oldHeight = w, h
+	end
+    end;
+
     respawnPlayer = function(self, playerIdx)
         self.planes[playerIdx] = self.makePlanes[playerIdx]()
     end;
@@ -70,6 +83,7 @@ Level = Class{
     end;
 
     drawBackground = function(self)
+	self:updateBackground()
         love.graphics.setColor(draw_base_color)
         love.graphics.draw(self.bgCanvas)
     end;
@@ -81,11 +95,11 @@ Level = Class{
             if entity:isinstance(PhysicsEntity) then
 	        local jump_window = 70
 		local jump_amount = 50
-                while entity.body:getX() > WIDTH + jump_window do
-                    entity.body:setX(entity.body:getX() - WIDTH - jump_window - jump_amount)
+                while entity.body:getX() > levelWidth() + jump_window do
+                    entity.body:setX(entity.body:getX() - levelWidth() - jump_window - jump_amount)
                 end
                 while entity.body:getX() < -jump_window do
-                    entity.body:setX(entity.body:getX() + WIDTH + jump_window + jump_amount)
+                    entity.body:setX(entity.body:getX() + levelWidth() + jump_window + jump_amount)
                 end
             end
             entity:update(dt)

level_state.lua

@@ -150,8 +150,8 @@ function level_state:update(dt)
 	local r = love.math.random()
 
 	if r <= POWERUP_POSSIBILITY * dt then
-	    local x = love.math.random(WIDTH)
-	    local y = love.math.random(HEIGHT)
+	    local x = love.math.random(levelWidth())
+	    local y = love.math.random(levelHeight())
 
 	    POWERUPS[love.math.random(1, #POWERUPS)](x, y, current_level)
 	end

menu_state.lua

@@ -144,7 +144,10 @@ end
 
 function menu_state:draw()
     love.graphics.setColor(128, 128, 128, 255)
-    love.graphics.draw(background)
+    love.graphics.draw(background, 0, 0, 0,
+		       levelWidth() / background:getWidth(),
+		       levelHeight() / background:getHeight())
+
 
     local seconds, subseconds = math.modf(menuTime)
 

settings.lua

@@ -8,8 +8,8 @@ PIXELS_PER_METER = 8
 GRAVITY_X = 0
 GRAVITY_Y = 9.82599 * PIXELS_PER_METER
 
-WIDTH = 1280
-HEIGHT = 768
+INITIAL_WIDTH = 1280
+INITIAL_HEIGHT = 768
 
 KEYMAP = {
     [1] = {
@@ -57,6 +57,16 @@ if love.filesystem.isFile("fysplane.cfg") then
     AXISMAP = m.AXISMAP
 end
 
+function levelWidth()
+    local width, height = love.window.getMode()
+    return width
+end
+
+function levelHeight()
+    local width, height = love.window.getMode()
+    return height
+end
+
 PLANE_HEALTH = 200
 PLANE_DEFAULT_GUN = "vickers77"