Licar mod for making TAS (tool assisted speedruns). This is a simple mod that
mainly adds one feature: instead of completely restarting a map, the restart key
rather rewinds time a little back. This allows to retry any part of a map as
many times as one desires. Loading a replay for viewing also loads the inputs
from the replay so that it's possible to reuse a start portion of another run.
It helps to slow down time in the settings and drive in slow motion.

diff --git a/assets.h b/assets.h
index 4629aaa..c9449f5 100644
--- a/assets.h
+++ b/assets.h
@@ -36,7 +36,7 @@
 static const char *LCR_texts[] =
 {
 #define LCR_TEXTS_VERSION 0
-  LCR_VERSION, // version string
+  LCR_VERSION " TAS mod", // version string
 #define LCR_TEXTS_TABS 1
   "main menu",
   "play map",
diff --git a/game.h b/game.h
index b1db32c..1743707 100644
--- a/game.h
+++ b/game.h
@@ -344,6 +344,9 @@ struct
   uint32_t runTime;                  ///< Current time of the run, in ticks.
   uint8_t mapBeaten;
 
+  uint8_t tasInputs[LCR_SETTING_TAS_MAX_INPUTS / 2 + 1];
+  unsigned int tasInputCount;
+
   char popupStr[LCR_POPUP_STR_SIZE];
   uint8_t popupCountdown;
 
@@ -504,8 +507,36 @@ void LCR_gameResetRun(uint8_t replay, uint8_t ghost)
   LCR_game.ghost.active = ghost;
 #endif
 
-  LCR_gameSetState(LCR_GAME_STATE_RUN_STARTING);
   LCR_game.runTime = 0;
+
+  if (!LCR_racing.replay.on)
+  {
+    LCR_game.tasInputCount = LCR_game.tasInputCount >= LCR_SETTING_TAS_REWIND ?
+      LCR_game.tasInputCount - LCR_SETTING_TAS_REWIND : 0;
+
+    for (unsigned int i = 0; i < LCR_game.tasInputCount; ++i)
+    {
+      if (LCR_racingStep((LCR_game.tasInputs[i / 2] >> ((i % 2) * 4)) & 0x0f)
+        == LCR_RACING_EVENT_CP_TAKEN)
+      {
+        int carBlock[3];
+        LCR_racingGetCarBlockCoords(carBlock);
+        LCR_rendererMarkTakenCP(carBlock[0],carBlock[1],carBlock[2]);
+      }
+
+      LCR_game.runTime = LCR_racing.tick;
+    }
+
+    LCR_gameSetState(LCR_GAME_STATE_RUN);
+    LCR_racingGetCarTransform(carTransform,carTransform + 3,0);
+    LCR_rendererSetCarTransform(carTransform,carTransform + 3);
+    LCR_rendererCameraReset();
+    LCR_rendererLoadMapChunks();
+    LCR_game.nextRenderFrameTime = LCR_game.time + 1000 / LCR_SETTING_FPS;
+    LCR_game.nextRacingTickTime = LCR_game.time + LCR_RACING_TICK_MS_RT;
+  }
+  else
+    LCR_gameSetState(LCR_GAME_STATE_RUN_STARTING);
 }
 
 void LCR_gameGetNthGhostSample(unsigned int n,
@@ -867,6 +898,7 @@ uint8_t LCR_gameLoadMap(unsigned int mapIndex)
 
   result = LCR_mapLoadFromStr(LCR_gameGetNextDataStrChar,name);
   LCR_game.mapBeaten = LCR_mapIsBeaten(LCR_currentMap.name);
+  LCR_game.tasInputCount = 0;
 
   return result;
 }
@@ -1708,6 +1740,23 @@ void LCR_gameHandleInput(void)
   }
 }
 
+void LCR_gameAddTASInput(uint8_t input)
+{
+  if (LCR_game.tasInputCount >= LCR_SETTING_TAS_MAX_INPUTS)
+  {
+    LCR_LOG1("maximum TAS inputs reached!");
+  }
+  else
+  {
+    uint8_t *inputRec = LCR_game.tasInputs + LCR_game.tasInputCount / 2;
+
+    *inputRec = (LCR_game.tasInputCount % 2) ?
+      *inputRec | ((input & 0x0f) << 4) : (input & 0x0f);
+
+    LCR_game.tasInputCount++;
+  }
+}
+
 uint8_t LCR_gameStep(uint32_t time)
 {
   LCR_LOG2("game step (start)");
@@ -1742,9 +1791,21 @@ uint8_t LCR_gameStep(uint32_t time)
     LCR_gameSetState(LCR_GAME_STATE_LOADED);
   }
   else if (LCR_game.state == LCR_GAME_STATE_LOADED)
-    LCR_gameResetRun( // start countdown now, loading the map lost many frames
-      LCR_game.menu.selectedTab == 2,
-      LCR_game.menu.selectedTab == 3);
+  {
+    if (LCR_game.menu.selectedTab == 2) // view replay? => load TAS inputs
+    {
+      LCR_replayInitPlaying();
+      LCR_game.tasInputCount = 0;
+
+      while (!LCR_replayHasFinished())
+        LCR_gameAddTASInput(LCR_replayGetNextInput());
+
+      LCR_game.menu.selectedTab = 3;
+      _LCR_gamePrepareGhost();
+    }
+
+    LCR_gameResetRun(0,LCR_game.menu.selectedTab == 3);
+  }
   else
   {
     LCR_gameHandleInput();
@@ -1765,6 +1826,9 @@ uint8_t LCR_gameStep(uint32_t time)
          (LCR_game.keyStates[LCR_KEY_DOWN]  ? LCR_RACING_INPUT_BACK  : 0) |
          (LCR_game.keyStates[LCR_KEY_LEFT]  ? LCR_RACING_INPUT_LEFT  : 0));
 
+      if (!paused && !LCR_racing.replay.on)
+        LCR_gameAddTASInput(input);
+
 #ifdef LCR_FPS_GET_MS
       frameTime = LCR_FPS_GET_MS;
 #endif
diff --git a/settings.h b/settings.h
index 332df45..b9b3aba 100644
--- a/settings.h
+++ b/settings.h
@@ -296,4 +296,14 @@
   #define LCR_SETTING_ONLY_SMALL_MAPS 0
 #endif
 
+#ifndef LCR_SETTING_TAS_MAX_INPUTS
+  /** Maximum possible length of a run in the TAS mod, in physics ticks. */
+  #define LCR_SETTING_TAS_MAX_INPUTS 4096
+#endif
+
+#ifndef LCR_SETTING_TAS_REWIND
+  /** Length of TAS rewind, in physics ticks. */
+  #define LCR_SETTING_TAS_REWIND 20
+#endif
+
 #endif // guard