rnd-20060102-1-src
[rocksndiamonds.git] / src / game.c
index f7272d14a9e67ede968ad3461ace4cc7df37fbdb..55ffb998d9285bf24dc928e1f7bec7e8fcf7e13a 100644 (file)
@@ -34,6 +34,7 @@
 #define USE_NEW_PLAYER_SPEED           (USE_NEW_STUFF          * 1)
 #define USE_NEW_DELAYED_ACTION         (USE_NEW_STUFF          * 1)
 #define USE_NEW_SNAP_DELAY             (USE_NEW_STUFF          * 1)
+#define USE_ONLY_ONE_CHANGE_PER_FRAME  (USE_NEW_STUFF          * 0)
 
 /* for DigField() */
 #define DF_NO_PUSH             0
 #define SCROLL_INIT            0
 #define SCROLL_GO_ON           1
 
-/* for Explode() */
+/* for Bang()/Explode() */
 #define EX_PHASE_START         0
 #define EX_TYPE_NONE           0
 #define EX_TYPE_NORMAL         (1 << 0)
 #define EX_TYPE_CENTER         (1 << 1)
 #define EX_TYPE_BORDER         (1 << 2)
 #define EX_TYPE_CROSS          (1 << 3)
+#define EX_TYPE_DYNA           (1 << 4)
 #define EX_TYPE_SINGLE_TILE    (EX_TYPE_CENTER | EX_TYPE_BORDER)
 
 /* special positions in the game control window (relative to control window) */
@@ -898,7 +900,7 @@ static void InitField(int x, int y, boolean init_game)
          InitMovDir(x, y);
 
 #if USE_NEW_CUSTOM_VALUE
-       if (!element_info[element].use_last_ce_value)
+       if (!element_info[element].use_last_ce_value || init_game)
          CustomValue[x][y] = GET_NEW_CUSTOM_VALUE(Feld[x][y]);
 #endif
       }
@@ -1137,7 +1139,7 @@ static void resolve_group_element(int group_element, int recursion_depth)
 
 static void InitGameEngine()
 {
-  int i, j, k, l;
+  int i, j, k, l, x, y;
 
   /* set game engine from tape file when re-playing, else from level file */
   game.engine_version = (tape.playing ? tape.engine_version :
@@ -1209,6 +1211,38 @@ static void InitGameEngine()
   game.use_block_last_field_bug =
     (game.engine_version < VERSION_IDENT(3,1,1,0));
 
+  /*
+    Summary of bugfix/change:
+    Changed behaviour of CE changes with multiple changes per single frame.
+
+    Fixed/changed in version:
+    3.2.0-6
+
+    Description:
+    Before 3.2.0-6, only one single CE change was allowed in each engine frame.
+    This resulted in race conditions where CEs seem to behave strange in some
+    situations (where triggered CE changes were just skipped because there was
+    already a CE change on that tile in the playfield in that engine frame).
+    Since 3.2.0-6, this was changed to allow up to MAX_NUM_CHANGES_PER_FRAME.
+    (The number of changes per frame must be limited in any case, because else
+    it is easily possible to define CE changes that would result in an infinite
+    loop, causing the whole game to freeze. The MAX_NUM_CHANGES_PER_FRAME value
+    should be set large enough so that it would only be reached in cases where
+    the corresponding CE change conditions run into a loop. Therefore, it seems
+    to be reasonable to set MAX_NUM_CHANGES_PER_FRAME to the same value as the
+    maximal number of change pages for custom elements.)
+
+    Affected levels/tapes:
+    Probably many.
+  */
+
+#if USE_ONLY_ONE_CHANGE_PER_FRAME
+  game.max_num_changes_per_frame = 1;
+#else
+  game.max_num_changes_per_frame =
+    (game.engine_version < VERSION_IDENT(3,2,0,6) ? 1 : 32);
+#endif
+
   /* ---------------------------------------------------------------------- */
 
   /* dynamically adjust element properties according to game engine version */
@@ -1472,6 +1506,40 @@ static void InitGameEngine()
   for (i = 0; access_direction_list[i].element != EL_UNDEFINED; i++)
     element_info[access_direction_list[i].element].access_direction =
       access_direction_list[i].direction;
+
+  /* ---------- initialize explosion content ------------------------------- */
+  for (i = 0; i < MAX_NUM_ELEMENTS; i++)
+  {
+    if (IS_CUSTOM_ELEMENT(i))
+      continue;
+
+    for (y = 0; y < 3; y++) for (x = 0; x < 3; x++)
+    {
+      /* (content for EL_YAMYAM set at run-time with game.yamyam_content_nr) */
+
+      element_info[i].content.e[x][y] =
+       (i == EL_PLAYER_1 ? EL_EMERALD_YELLOW :
+        i == EL_PLAYER_2 ? EL_EMERALD_RED :
+        i == EL_PLAYER_3 ? EL_EMERALD :
+        i == EL_PLAYER_4 ? EL_EMERALD_PURPLE :
+        i == EL_MOLE ? EL_EMERALD_RED :
+        i == EL_PENGUIN ? EL_EMERALD_PURPLE :
+        i == EL_BUG ? (x == 1 && y == 1 ? EL_DIAMOND : EL_EMERALD) :
+        i == EL_BD_BUTTERFLY ? EL_BD_DIAMOND :
+        i == EL_SP_ELECTRON ? EL_SP_INFOTRON :
+        i == EL_AMOEBA_TO_DIAMOND ? level.amoeba_content :
+        i == EL_YAMYAM ? EL_UNDEFINED :
+        i == EL_WALL_EMERALD ? EL_EMERALD :
+        i == EL_WALL_DIAMOND ? EL_DIAMOND :
+        i == EL_WALL_BD_DIAMOND ? EL_BD_DIAMOND :
+        i == EL_WALL_EMERALD_YELLOW ? EL_EMERALD_YELLOW :
+        i == EL_WALL_EMERALD_RED ? EL_EMERALD_RED :
+        i == EL_WALL_EMERALD_PURPLE ? EL_EMERALD_PURPLE :
+        i == EL_WALL_PEARL ? EL_PEARL :
+        i == EL_WALL_CRYSTAL ? EL_CRYSTAL :
+        EL_EMPTY);
+    }
+  }
 }
 
 int get_num_special_action(int element, int action_first, int action_last)
@@ -1555,7 +1623,9 @@ void InitGame()
     player->StepFrame = 0;
 
     player->use_murphy = FALSE;
-    player->artwork_element = player->element_nr;
+    player->artwork_element =
+      (level.use_artwork_element[i] ? level.artwork_element[i] :
+       player->element_nr);
 
     player->block_last_field = FALSE;  /* initialized in InitPlayerField() */
     player->block_delay_adjustment = 0;        /* initialized in InitPlayerField() */
@@ -1673,6 +1743,9 @@ void InitGame()
   game.gravity = level.initial_gravity;
   game.explosions_delayed = TRUE;
 
+  game.lenses_time_left = 0;
+  game.magnify_time_left = 0;
+
   game.envelope_active = FALSE;
 
   for (i = 0; i < NUM_BELTS; i++)
@@ -1703,7 +1776,7 @@ void InitGame()
       Stop[x][y] = FALSE;
       Pushed[x][y] = FALSE;
 
-      Changed[x][y] = FALSE;
+      Changed[x][y] = 0;
       ChangeEvent[x][y] = -1;
 
       ExplodePhase[x][y] = 0;
@@ -2990,6 +3063,21 @@ void Explode(int ex, int ey, int phase, int mode)
   if (phase == EX_PHASE_START)         /* initialize 'Store[][]' field */
   {
     int center_element = Feld[ex][ey];
+    int artwork_element = center_element;      /* for custom player artwork */
+    int explosion_element = center_element;    /* for custom player artwork */
+
+    if (IS_PLAYER(ex, ey))
+    {
+      int player_nr = GET_PLAYER_NR(StorePlayer[ex][ey]);
+
+      artwork_element = stored_player[player_nr].artwork_element;
+
+      if (level.use_explosion_element[player_nr])
+      {
+       explosion_element = level.explosion_element[player_nr];
+       artwork_element = explosion_element;
+      }
+    }
 
 #if 0
     /* --- This is only really needed (and now handled) in "Impact()". --- */
@@ -3003,7 +3091,7 @@ void Explode(int ex, int ey, int phase, int mode)
     if (mode == EX_TYPE_NORMAL ||
        mode == EX_TYPE_CENTER ||
        mode == EX_TYPE_CROSS)
-      PlayLevelSoundAction(ex, ey, ACTION_EXPLODING);
+      PlayLevelSoundElementAction(ex, ey, artwork_element, ACTION_EXPLODING);
 
     /* remove things displayed in background while burning dynamite */
     if (Back[ex][ey] != EL_EMPTY && !IS_INDESTRUCTIBLE(Back[ex][ey]))
@@ -3017,7 +3105,7 @@ void Explode(int ex, int ey, int phase, int mode)
       Feld[ex][ey] = center_element;
     }
 
-    last_phase = element_info[center_element].explosion_delay + 1;
+    last_phase = element_info[explosion_element].explosion_delay + 1;
 
     for (y = ey - 1; y <= ey + 1; y++) for (x = ex - 1; x <= ex + 1; x++)
     {
@@ -3090,6 +3178,11 @@ void Explode(int ex, int ey, int phase, int mode)
 
       if (IS_PLAYER(ex, ey) && !PLAYER_EXPLOSION_PROTECTED(ex, ey))
       {
+       int player_nr = StorePlayer[ex][ey] - EL_PLAYER_1;
+
+       Store[x][y] = EL_PLAYER_IS_EXPLODING_1 + player_nr;
+
+#if 0
        switch(StorePlayer[ex][ey])
        {
          case EL_PLAYER_2:
@@ -3106,10 +3199,21 @@ void Explode(int ex, int ey, int phase, int mode)
            Store[x][y] = EL_PLAYER_IS_EXPLODING_1;
            break;
        }
+#endif
 
        if (PLAYERINFO(ex, ey)->use_murphy)
          Store[x][y] = EL_EMPTY;
       }
+#if 1
+      else if (center_element == EL_YAMYAM)
+       Store[x][y] = level.yamyam_content[game.yamyam_content_nr].e[xx][yy];
+      else if (element_info[center_element].content.e[xx][yy] != EL_EMPTY)
+       Store[x][y] = element_info[center_element].content.e[xx][yy];
+      else if (!CAN_EXPLODE(element))
+       Store[x][y] = element_info[element].content.e[1][1];
+      else
+       Store[x][y] = EL_EMPTY;
+#else
       else if (center_element == EL_MOLE)
        Store[x][y] = EL_EMERALD_RED;
       else if (center_element == EL_PENGUIN)
@@ -3147,13 +3251,14 @@ void Explode(int ex, int ey, int phase, int mode)
        Store[x][y] = element_info[element].content.e[1][1];
       else
        Store[x][y] = EL_EMPTY;
+#endif
 
       if (x != ex || y != ey || mode == EX_TYPE_BORDER ||
          center_element == EL_AMOEBA_TO_DIAMOND)
        Store2[x][y] = element;
 
       Feld[x][y] = EL_EXPLOSION;
-      GfxElement[x][y] = center_element;
+      GfxElement[x][y] = artwork_element;
 
       ExplodePhase[x][y] = 1;
       ExplodeDelay[x][y] = last_phase;
@@ -3247,12 +3352,30 @@ void Explode(int ex, int ey, int phase, int mode)
     /* player can escape from explosions and might therefore be still alive */
     if (element >= EL_PLAYER_IS_EXPLODING_1 &&
        element <= EL_PLAYER_IS_EXPLODING_4)
-      Feld[x][y] = (stored_player[element - EL_PLAYER_IS_EXPLODING_1].active ?
-                   EL_EMPTY :
-                   element == EL_PLAYER_IS_EXPLODING_1 ? EL_EMERALD_YELLOW :
-                   element == EL_PLAYER_IS_EXPLODING_2 ? EL_EMERALD_RED :
-                   element == EL_PLAYER_IS_EXPLODING_3 ? EL_EMERALD :
-                   EL_EMERALD_PURPLE);
+    {
+      static int player_death_elements[] =
+      {
+       EL_EMERALD_YELLOW,
+       EL_EMERALD_RED,
+       EL_EMERALD,
+       EL_EMERALD_PURPLE
+      };
+      int player_nr = element - EL_PLAYER_IS_EXPLODING_1;
+      int player_death_element = player_death_elements[player_nr];
+
+      if (level.use_explosion_element[player_nr])
+      {
+       int explosion_element = level.explosion_element[player_nr];
+       int xx = MIN(MAX(0, x - stored_player[player_nr].jx + 1), 2);
+       int yy = MIN(MAX(0, y - stored_player[player_nr].jy + 1), 2);
+
+       player_death_element =
+         element_info[explosion_element].content.e[xx][yy];
+      }
+
+      Feld[x][y] = (stored_player[player_nr].active ? EL_EMPTY :
+                   player_death_element);
+    }
 
     /* restore probably existing indestructible background element */
     if (Back[x][y] && IS_INDESTRUCTIBLE(Back[x][y]))
@@ -3360,6 +3483,7 @@ void DynaExplode(int ex, int ey)
 void Bang(int x, int y)
 {
   int element = MovingOrBlocked2Element(x, y);
+  int explosion_type = EX_TYPE_NORMAL;
 
   if (IS_PLAYER(x, y) && !PLAYER_EXPLOSION_PROTECTED(x, y))
   {
@@ -3367,6 +3491,16 @@ void Bang(int x, int y)
 
     element = Feld[x][y] = (player->use_murphy ? EL_SP_MURPHY :
                            player->element_nr);
+
+    if (level.use_explosion_element[player->index_nr])
+    {
+      int explosion_element = level.explosion_element[player->index_nr];
+
+      if (element_info[explosion_element].explosion_type == EXPLODES_CROSS)
+       explosion_type = EX_TYPE_CROSS;
+      else if (element_info[explosion_element].explosion_type == EXPLODES_1X1)
+       explosion_type = EX_TYPE_CENTER;
+    }
   }
 
   switch(element)
@@ -3381,8 +3515,8 @@ void Bang(int x, int y)
     case EL_PACMAN:
     case EL_MOLE:
       RaiseScoreElement(element);
-      Explode(x, y, EX_PHASE_START, EX_TYPE_NORMAL);
       break;
+
     case EL_DYNABOMB_PLAYER_1_ACTIVE:
     case EL_DYNABOMB_PLAYER_2_ACTIVE:
     case EL_DYNABOMB_PLAYER_3_ACTIVE:
@@ -3390,27 +3524,30 @@ void Bang(int x, int y)
     case EL_DYNABOMB_INCREASE_NUMBER:
     case EL_DYNABOMB_INCREASE_SIZE:
     case EL_DYNABOMB_INCREASE_POWER:
-      DynaExplode(x, y);
+      explosion_type = EX_TYPE_DYNA;
       break;
+
     case EL_PENGUIN:
     case EL_LAMP:
     case EL_LAMP_ACTIVE:
     case EL_AMOEBA_TO_DIAMOND:
-      if (IS_PLAYER(x, y))
-       Explode(x, y, EX_PHASE_START, EX_TYPE_NORMAL);
-      else
-       Explode(x, y, EX_PHASE_START, EX_TYPE_CENTER);
+      if (!IS_PLAYER(x, y))    /* penguin and player may be at same field */
+       explosion_type = EX_TYPE_CENTER;
       break;
+
     default:
       if (element_info[element].explosion_type == EXPLODES_CROSS)
-       Explode(x, y, EX_PHASE_START, EX_TYPE_CROSS);
+       explosion_type = EX_TYPE_CROSS;
       else if (element_info[element].explosion_type == EXPLODES_1X1)
-       Explode(x, y, EX_PHASE_START, EX_TYPE_CENTER);
-      else
-       Explode(x, y, EX_PHASE_START, EX_TYPE_NORMAL);
+       explosion_type = EX_TYPE_CENTER;
       break;
   }
 
+  if (explosion_type == EX_TYPE_DYNA)
+    DynaExplode(x, y);
+  else
+    Explode(x, y, EX_PHASE_START, explosion_type);
+
   CheckTriggeredElementChange(x, y, element, CE_EXPLOSION_OF_X);
 }
 
@@ -3648,50 +3785,155 @@ static void RedrawAllLightSwitchesAndInvisibleElements()
 {
   int x, y;
 
-  for (y = 0; y < lev_fieldy; y++)
+  for (y = 0; y < lev_fieldy; y++) for (x = 0; x < lev_fieldx; x++)
   {
-    for (x = 0; x < lev_fieldx; x++)
+    int element = Feld[x][y];
+
+    if (element == EL_LIGHT_SWITCH &&
+       game.light_time_left > 0)
     {
-      int element = Feld[x][y];
+      Feld[x][y] = EL_LIGHT_SWITCH_ACTIVE;
+      DrawLevelField(x, y);
+    }
+    else if (element == EL_LIGHT_SWITCH_ACTIVE &&
+            game.light_time_left == 0)
+    {
+      Feld[x][y] = EL_LIGHT_SWITCH;
+      DrawLevelField(x, y);
+    }
+    else if (element == EL_EMC_DRIPPER &&
+            game.light_time_left > 0)
+    {
+      Feld[x][y] = EL_EMC_DRIPPER_ACTIVE;
+      DrawLevelField(x, y);
+    }
+    else if (element == EL_EMC_DRIPPER_ACTIVE &&
+            game.light_time_left == 0)
+    {
+      Feld[x][y] = EL_EMC_DRIPPER;
+      DrawLevelField(x, y);
+    }
+    else if (element == EL_INVISIBLE_STEELWALL ||
+            element == EL_INVISIBLE_WALL ||
+            element == EL_INVISIBLE_SAND)
+    {
+      if (game.light_time_left > 0)
+       Feld[x][y] = getInvisibleActiveFromInvisibleElement(element);
 
-      if (element == EL_LIGHT_SWITCH &&
-         game.light_time_left > 0)
-      {
-       Feld[x][y] = EL_LIGHT_SWITCH_ACTIVE;
-       DrawLevelField(x, y);
-      }
-      else if (element == EL_LIGHT_SWITCH_ACTIVE &&
-              game.light_time_left == 0)
-      {
-       Feld[x][y] = EL_LIGHT_SWITCH;
-       DrawLevelField(x, y);
-      }
-      else if (element == EL_INVISIBLE_STEELWALL ||
-              element == EL_INVISIBLE_WALL ||
-              element == EL_INVISIBLE_SAND)
-      {
-       if (game.light_time_left > 0)
-         Feld[x][y] = getInvisibleActiveFromInvisibleElement(element);
+      DrawLevelField(x, y);
 
-       DrawLevelField(x, y);
+      /* uncrumble neighbour fields, if needed */
+      if (element == EL_INVISIBLE_SAND)
+       DrawLevelFieldCrumbledSandNeighbours(x, y);
+    }
+    else if (element == EL_INVISIBLE_STEELWALL_ACTIVE ||
+            element == EL_INVISIBLE_WALL_ACTIVE ||
+            element == EL_INVISIBLE_SAND_ACTIVE)
+    {
+      if (game.light_time_left == 0)
+       Feld[x][y] = getInvisibleFromInvisibleActiveElement(element);
 
-       /* uncrumble neighbour fields, if needed */
-       if (element == EL_INVISIBLE_SAND)
-         DrawLevelFieldCrumbledSandNeighbours(x, y);
-      }
-      else if (element == EL_INVISIBLE_STEELWALL_ACTIVE ||
-              element == EL_INVISIBLE_WALL_ACTIVE ||
-              element == EL_INVISIBLE_SAND_ACTIVE)
-      {
-       if (game.light_time_left == 0)
-         Feld[x][y] = getInvisibleFromInvisibleActiveElement(element);
+      DrawLevelField(x, y);
 
-       DrawLevelField(x, y);
+      /* re-crumble neighbour fields, if needed */
+      if (element == EL_INVISIBLE_SAND)
+       DrawLevelFieldCrumbledSandNeighbours(x, y);
+    }
+  }
+}
 
-       /* re-crumble neighbour fields, if needed */
-       if (element == EL_INVISIBLE_SAND)
-         DrawLevelFieldCrumbledSandNeighbours(x, y);
-      }
+static void RedrawAllInvisibleElementsForLenses()
+{
+  int x, y;
+
+  for (y = 0; y < lev_fieldy; y++) for (x = 0; x < lev_fieldx; x++)
+  {
+    int element = Feld[x][y];
+
+    if (element == EL_EMC_DRIPPER &&
+       game.lenses_time_left > 0)
+    {
+      Feld[x][y] = EL_EMC_DRIPPER_ACTIVE;
+      DrawLevelField(x, y);
+    }
+    else if (element == EL_EMC_DRIPPER_ACTIVE &&
+            game.lenses_time_left == 0)
+    {
+      Feld[x][y] = EL_EMC_DRIPPER;
+      DrawLevelField(x, y);
+    }
+    else if (element == EL_INVISIBLE_STEELWALL ||
+            element == EL_INVISIBLE_WALL ||
+            element == EL_INVISIBLE_SAND)
+    {
+      if (game.lenses_time_left > 0)
+       Feld[x][y] = getInvisibleActiveFromInvisibleElement(element);
+
+      DrawLevelField(x, y);
+
+      /* uncrumble neighbour fields, if needed */
+      if (element == EL_INVISIBLE_SAND)
+       DrawLevelFieldCrumbledSandNeighbours(x, y);
+    }
+    else if (element == EL_INVISIBLE_STEELWALL_ACTIVE ||
+            element == EL_INVISIBLE_WALL_ACTIVE ||
+            element == EL_INVISIBLE_SAND_ACTIVE)
+    {
+      if (game.lenses_time_left == 0)
+       Feld[x][y] = getInvisibleFromInvisibleActiveElement(element);
+
+      DrawLevelField(x, y);
+
+      /* re-crumble neighbour fields, if needed */
+      if (element == EL_INVISIBLE_SAND)
+       DrawLevelFieldCrumbledSandNeighbours(x, y);
+    }
+  }
+}
+
+static void RedrawAllInvisibleElementsForMagnifier()
+{
+  int x, y;
+
+  for (y = 0; y < lev_fieldy; y++) for (x = 0; x < lev_fieldx; x++)
+  {
+    int element = Feld[x][y];
+
+    if (element == EL_EMC_FAKE_GRASS &&
+       game.magnify_time_left > 0)
+    {
+      Feld[x][y] = EL_EMC_FAKE_GRASS_ACTIVE;
+      DrawLevelField(x, y);
+    }
+    else if (element == EL_EMC_FAKE_GRASS_ACTIVE &&
+            game.magnify_time_left == 0)
+    {
+      Feld[x][y] = EL_EMC_FAKE_GRASS;
+      DrawLevelField(x, y);
+    }
+    else if (IS_GATE_GRAY(element) &&
+            game.magnify_time_left > 0)
+    {
+      Feld[x][y] = (IS_RND_GATE_GRAY(element) ?
+                   element - EL_GATE_1_GRAY + EL_GATE_1_GRAY_ACTIVE :
+                   IS_EM_GATE_GRAY(element) ?
+                   element - EL_EM_GATE_1_GRAY + EL_EM_GATE_1_GRAY_ACTIVE :
+                   IS_EMC_GATE_GRAY(element) ?
+                   element - EL_EMC_GATE_5_GRAY + EL_EMC_GATE_5_GRAY_ACTIVE :
+                   element);
+      DrawLevelField(x, y);
+    }
+    else if (IS_GATE_GRAY_ACTIVE(element) &&
+            game.magnify_time_left == 0)
+    {
+      Feld[x][y] = (IS_RND_GATE_GRAY_ACTIVE(element) ?
+                   element - EL_GATE_1_GRAY_ACTIVE + EL_GATE_1_GRAY :
+                   IS_EM_GATE_GRAY_ACTIVE(element) ?
+                   element - EL_EM_GATE_1_GRAY_ACTIVE + EL_EM_GATE_1_GRAY :
+                   IS_EMC_GATE_GRAY_ACTIVE(element) ?
+                   element - EL_EMC_GATE_5_GRAY_ACTIVE + EL_EMC_GATE_5_GRAY :
+                   element);
+      DrawLevelField(x, y);
     }
   }
 }
@@ -5567,7 +5809,7 @@ void ContinueMoving(int x, int y)
 
   ChangeDelay[x][y] = 0;
   ChangePage[x][y] = -1;
-  Changed[x][y] = FALSE;
+  Changed[x][y] = 0;
   ChangeEvent[x][y] = -1;
 
 #if USE_NEW_CUSTOM_VALUE
@@ -6901,7 +7143,9 @@ static void ExecuteCustomElementAction(int x, int y, int element, int page)
          int artwork_element = action_arg_element;
 
          if (action_arg == CA_ARG_ELEMENT_RESET)
-           artwork_element = stored_player[i].element_nr;
+           artwork_element =
+             (level.use_artwork_element[i] ? level.artwork_element[i] :
+              stored_player[i].element_nr);
 
          stored_player[i].artwork_element = artwork_element;
 
@@ -7010,11 +7254,7 @@ static void ChangeElementNowExt(struct ElementChangeInfo *change,
   if (ELEM_IS_PLAYER(target_element))
     RelocatePlayer(x, y, target_element);
 
-#if 1
-  Changed[x][y] = TRUE;                /* ignore all further changes in this frame */
-#else
-  Changed[x][y] |= ChangeEvent[x][y];  /* ignore same changes in this frame */
-#endif
+  Changed[x][y]++;             /* count number of changes in the same frame */
 
   TestIfBadThingTouchesPlayer(x, y);
   TestIfPlayerTouchesCustomElement(x, y);
@@ -7040,21 +7280,11 @@ static boolean ChangeElementNow(int x, int y, int element, int page)
     change->actual_trigger_ce_value = 0;
   }
 
-#if 1
-  /* do not change any elements that have already changed in this frame */
-  if (Changed[x][y])
+  /* do not change elements more than a specified maximum number of changes */
+  if (Changed[x][y] >= game.max_num_changes_per_frame)
     return FALSE;
-#else
-  /* do not change already changed elements with same change event */
-  if (Changed[x][y] & ChangeEvent[x][y])
-    return FALSE;
-#endif
 
-#if 1
-  Changed[x][y] = TRUE;                /* ignore all further changes in this frame */
-#else
-  Changed[x][y] |= ChangeEvent[x][y];  /* ignore same changes in this frame */
-#endif
+  Changed[x][y]++;             /* count number of changes in the same frame */
 
   if (change->explode)
   {
@@ -7936,7 +8166,7 @@ void GameActions()
 
   for (y = 0; y < lev_fieldy; y++) for (x = 0; x < lev_fieldx; x++)
   {
-    Changed[x][y] = FALSE;
+    Changed[x][y] = 0;
     ChangeEvent[x][y] = -1;
 
     /* this must be handled before main playfield loop */
@@ -8258,6 +8488,22 @@ void GameActions()
       CloseAllOpenTimegates();
   }
 
+  if (game.lenses_time_left > 0)
+  {
+    game.lenses_time_left--;
+
+    if (game.lenses_time_left == 0)
+      RedrawAllInvisibleElementsForLenses();
+  }
+
+  if (game.magnify_time_left > 0)
+  {
+    game.magnify_time_left--;
+
+    if (game.magnify_time_left == 0)
+      RedrawAllInvisibleElementsForMagnifier();
+  }
+
   for (i = 0; i < MAX_PLAYERS; i++)
   {
     struct PlayerInfo *player = &stored_player[i];
@@ -8528,8 +8774,19 @@ boolean MovePlayerOneStep(struct PlayerInfo *player,
 
   if (player->cannot_move)
   {
+#if 1
+    if (player->MovPos == 0)
+    {
+      player->is_moving = FALSE;
+      player->is_digging = FALSE;
+      player->is_collecting = FALSE;
+      player->is_snapping = FALSE;
+      player->is_pushing = FALSE;
+    }
+#else
     DigField(player, 0, 0, 0, 0, 0, 0, DF_NO_PUSH);
     SnapField(player, 0, 0);
+#endif
 
     return MF_NO_ACTION;
   }
@@ -9706,6 +9963,11 @@ int DigField(struct PlayerInfo *player,
       if (!player->key[RND_GATE_GRAY_NR(element)])
        return MF_NO_ACTION;
     }
+    else if (IS_RND_GATE_GRAY_ACTIVE(element))
+    {
+      if (!player->key[RND_GATE_GRAY_ACTIVE_NR(element)])
+       return MF_NO_ACTION;
+    }
     else if (element == EL_EXIT_OPEN ||
             element == EL_SP_EXIT_OPEN ||
             element == EL_SP_EXIT_OPENING)
@@ -9741,6 +10003,11 @@ int DigField(struct PlayerInfo *player,
       if (!player->key[EM_GATE_GRAY_NR(element)])
        return MF_NO_ACTION;
     }
+    else if (IS_EM_GATE_GRAY_ACTIVE(element))
+    {
+      if (!player->key[EM_GATE_GRAY_ACTIVE_NR(element)])
+       return MF_NO_ACTION;
+    }
     else if (IS_SP_PORT(element))
     {
       if (element == EL_SP_GRAVITY_PORT_LEFT ||
@@ -9859,6 +10126,18 @@ int DigField(struct PlayerInfo *player,
     {
       player->show_envelope = element;
     }
+    else if (element == EL_EMC_LENSES)
+    {
+      game.lenses_time_left = level.lenses_time * FRAMES_PER_SECOND;
+
+      RedrawAllInvisibleElementsForLenses();
+    }
+    else if (element == EL_EMC_MAGNIFIER)
+    {
+      game.magnify_time_left = level.magnify_time * FRAMES_PER_SECOND;
+
+      RedrawAllInvisibleElementsForMagnifier();
+    }
     else if (IS_DROPPABLE(element) ||
             IS_THROWABLE(element))     /* can be collected and dropped */
     {
@@ -10322,7 +10601,7 @@ boolean DropElement(struct PlayerInfo *player)
     PlayLevelSoundAction(dropx, dropy, ACTION_DROPPING);
 
     /* needed if previous element just changed to "empty" in the last frame */
-    Changed[dropx][dropy] = FALSE;             /* allow another change */
+    Changed[dropx][dropy] = 0;         /* allow at least one more change */
 
     CheckElementChangeByPlayer(dropx, dropy, new_element, CE_DROPPED_BY_PLAYER,
                               player->index_bit, drop_side);
@@ -10362,7 +10641,7 @@ boolean DropElement(struct PlayerInfo *player)
     nextx = dropx + GET_DX_FROM_DIR(move_direction);
     nexty = dropy + GET_DY_FROM_DIR(move_direction);
 
-    Changed[dropx][dropy] = FALSE;             /* allow another change */
+    Changed[dropx][dropy] = 0;         /* allow at least one more change */
     CheckCollision[dropx][dropy] = 2;
   }