Many changes all around. Started main menu.

Added Drawable, Sprite and SoundEffect classes.
Added comments to Fader class.

src/gstates/menu.lua

@@ -0,0 +1,86 @@
+------------------------------------------------------------------------------
+-- Imports
+------------------------------------------------------------------------------
+
+local love        = require 'love'
+local make_class  = require 'src.utils.classes'
+local GameState   = require 'src.gstates.gstate'
+local Fader       = require 'src.utils.fader'
+local Cursor      = require 'src.ui.cursor'
+local SoundEffect = require 'src.utils.sfx'
+
+
+------------------------------------------------------------------------------
+-- Class definitions
+------------------------------------------------------------------------------
+
+local MainMenu = make_class(GameState)
+
+
+------------------------------------------------------------------------------
+-- Class methods
+------------------------------------------------------------------------------
+
+function MainMenu:_init(name, index)
+    GameState._init(self, name, index)
+    self.skip  = false
+    self.fade  = Fader()
+
+    -- Create a mouse cursor object at the current mouse position.
+    local mx, my = love.mouse.getPosition()
+    self.cursor = Cursor(mx, my)
+
+    -- Create sound effects.
+    self.bgm = SoundEffect('bgm/eskisky.wav')
+end
+
+
+function MainMenu:load()
+    -- Load sprites.
+    self.cursor:load()
+
+    -- Load sound effects and start playing the background music
+    self.bgm:load()
+    self.bgm:play()
+end
+
+
+function MainMenu:update(dt)
+    -- Update the fader.
+    self.fade:update(dt)
+
+    -- Move on to the next game state if the user skipped the intro or all stages are complete.
+    if not self.skip then return self.index else return -1 end
+end
+
+
+function MainMenu:draw()
+    self.cursor:draw()
+    self.fade:draw()
+end
+
+
+function MainMenu:unload()
+    self.cursor:unload()
+    self.bgm:unload()
+end
+
+
+function MainMenu:keypressed(key)
+    -- Skip the intro on any key press.
+    if key == "escape" then
+        self.skip = true
+    end
+end
+
+
+function MainMenu:mousemoved(x, y, dx, dy)
+    self.cursor:mousemoved(x, y, dx, dy)
+end
+
+
+------------------------------------------------------------------------------
+-- Module return
+------------------------------------------------------------------------------
+
+return MainMenu