detect when mario is controllable

_NOTICE

@@ -5,7 +5,6 @@ however, feel free to copy any snippets of code you find useful.
 TODOs: (that i can remember right now)
 - normalize and/or embed sprite type inputs
 - settle on a network architecture
-- detect frames when Mario is in a controllable state
 - compute how many input neurons the network needs instead of hardcoding
 - add some detection for enemies later in the game
 - fix cfg.enable_overlay (smb.lua doesn't see it being changed)

main.lua

@@ -603,7 +603,7 @@ local function doit(dummy)
     empty(game.tile_input)
     empty(game.extra_input)
 
-    -- TODO: check if mario is in a playable state.
+    local controllable = game.R(0x757) == 0 and game.R(0x758) == 0
     local x, y = game.getxy(0, 0x86, 0xCE, 0x6D, 0xB5)
     local powerup = game.R(0x754)
     local status = game.R(0x756)
@@ -644,7 +644,7 @@ local function doit(dummy)
 
     if cfg.decrement_reward and reward_delta == 0 then reward_delta = reward_delta - 1 end
 
-    if not ingame_paused and game.get_state() ~= 'win_walking' then
+    if not ingame_paused and controllable and game.get_state() ~= 'win_walking' then
         -- note that we exclude points gained walking into the castle.
         -- this way, we avoid adding the timer-based fireworks to our reward,
         -- which are basically unwanted noise due to the way they trigger.