rnd-20030902-1-src
[rocksndiamonds.git] / src / game.c
index 5b22dcbd4f7d511af5972303033fe20a6f5bae44..91c8841ab9657c815e9cdb87359febc4adf9b0d7 100644 (file)
@@ -171,7 +171,6 @@ static void TestIfElementTouchesCustomElement(int, int);
 
 static boolean CheckTriggeredElementChange(int, int, int, int);
 static boolean CheckElementChange(int, int, int, int);
-static void ChangeElementNow(int, int, int);
 
 static void PlaySoundLevel(int, int, int);
 static void PlaySoundLevelNearest(int, int, int);
@@ -216,7 +215,7 @@ struct ChangingElementInfo
   void (*post_change_function)(int x, int y);
 };
 
-static struct ChangingElementInfo changing_element_list[] =
+static struct ChangingElementInfo change_delay_list[] =
 {
   {
     EL_NUT_BREAKING,
@@ -398,9 +397,9 @@ move_stepsize_list[] =
 struct
 {
   int element;
-  int gem_count;
+  int count;
 }
-gem_count_list[] =
+collect_count_list[] =
 {
   { EL_EMERALD,                        1 },
   { EL_BD_DIAMOND,             1 },
@@ -415,19 +414,21 @@ gem_count_list[] =
   { EL_UNDEFINED,              0 },
 };
 
-static boolean changing_element[MAX_NUM_ELEMENTS];
 static unsigned long trigger_events[MAX_NUM_ELEMENTS];
 
-#define IS_AUTO_CHANGING(e)    (changing_element[e])
+#define IS_AUTO_CHANGING(e)    (element_info[e].change_events & \
+                                CH_EVENT_BIT(CE_DELAY))
 #define IS_JUST_CHANGING(x, y) (ChangeDelay[x][y] != 0)
 #define IS_CHANGING(x, y)      (IS_AUTO_CHANGING(Feld[x][y]) || \
                                 IS_JUST_CHANGING(x, y))
 
+#define CE_PAGE(e, ce)         (element_info[e].event_page[ce])
+
 
 void GetPlayerConfig()
 {
   if (!audio.sound_available)
-    setup.sound = FALSE;
+    setup.sound_simple = FALSE;
 
   if (!audio.loops_available)
     setup.sound_loops = FALSE;
@@ -438,7 +439,7 @@ void GetPlayerConfig()
   if (!video.fullscreen_available)
     setup.fullscreen = FALSE;
 
-  setup.sound_simple = setup.sound;
+  setup.sound = (setup.sound_simple || setup.sound_loops || setup.sound_music);
 
   SetAudioMode(setup.sound);
   InitJoysticks();
@@ -495,62 +496,71 @@ static int getBeltDirFromBeltSwitchElement(int element)
   return belt_move_dir[belt_dir_nr];
 }
 
-static void InitField(int x, int y, boolean init_game)
+static void InitPlayerField(int x, int y, int element, boolean init_game)
 {
-  int element = Feld[x][y];
-
-  switch (element)
+  if (element == EL_SP_MURPHY)
   {
-    case EL_SP_MURPHY:
-      if (init_game)
+    if (init_game)
+    {
+      if (stored_player[0].present)
       {
-       if (stored_player[0].present)
-       {
-         Feld[x][y] = EL_SP_MURPHY_CLONE;
-         break;
-       }
-       else
-       {
-         stored_player[0].use_murphy_graphic = TRUE;
-       }
+       Feld[x][y] = EL_SP_MURPHY_CLONE;
 
-       Feld[x][y] = EL_PLAYER_1;
+       return;
       }
-      /* no break! */
-    case EL_PLAYER_1:
-    case EL_PLAYER_2:
-    case EL_PLAYER_3:
-    case EL_PLAYER_4:
-      if (init_game)
+      else
       {
-       struct PlayerInfo *player = &stored_player[Feld[x][y] - EL_PLAYER_1];
-       int jx = player->jx, jy = player->jy;
+       stored_player[0].use_murphy_graphic = TRUE;
+      }
 
-       player->present = TRUE;
+      Feld[x][y] = EL_PLAYER_1;
+    }
+  }
 
-       if (!options.network || player->connected)
-       {
-         player->active = TRUE;
+  if (init_game)
+  {
+    struct PlayerInfo *player = &stored_player[Feld[x][y] - EL_PLAYER_1];
+    int jx = player->jx, jy = player->jy;
 
-         /* remove potentially duplicate players */
-         if (StorePlayer[jx][jy] == Feld[x][y])
-           StorePlayer[jx][jy] = 0;
+    player->present = TRUE;
+
+    if (!options.network || player->connected)
+    {
+      player->active = TRUE;
 
-         StorePlayer[x][y] = Feld[x][y];
+      /* remove potentially duplicate players */
+      if (StorePlayer[jx][jy] == Feld[x][y])
+       StorePlayer[jx][jy] = 0;
 
-         if (options.debug)
-         {
-           printf("Player %d activated.\n", player->element_nr);
-           printf("[Local player is %d and currently %s.]\n",
-                  local_player->element_nr,
-                  local_player->active ? "active" : "not active");
-         }
-       }
+      StorePlayer[x][y] = Feld[x][y];
 
-       Feld[x][y] = EL_EMPTY;
-       player->jx = player->last_jx = x;
-       player->jy = player->last_jy = y;
+      if (options.debug)
+      {
+       printf("Player %d activated.\n", player->element_nr);
+       printf("[Local player is %d and currently %s.]\n",
+              local_player->element_nr,
+              local_player->active ? "active" : "not active");
       }
+    }
+
+    Feld[x][y] = EL_EMPTY;
+    player->jx = player->last_jx = x;
+    player->jy = player->last_jy = y;
+  }
+}
+
+static void InitField(int x, int y, boolean init_game)
+{
+  int element = Feld[x][y];
+
+  switch (element)
+  {
+    case EL_SP_MURPHY:
+    case EL_PLAYER_1:
+    case EL_PLAYER_2:
+    case EL_PLAYER_3:
+    case EL_PLAYER_4:
+      InitPlayerField(x, y, element, init_game);
       break;
 
     case EL_STONEBLOCK:
@@ -715,7 +725,7 @@ void DrawGameDoorValues()
   DrawText(DX + XX_EMERALDS, DY + YY_EMERALDS,
           int2str(local_player->gems_still_needed, 3), FONT_TEXT_2);
   DrawText(DX + XX_DYNAMITE, DY + YY_DYNAMITE,
-          int2str(local_player->dynamite, 3), FONT_TEXT_2);
+          int2str(local_player->inventory_size, 3), FONT_TEXT_2);
   DrawText(DX + XX_SCORE, DY + YY_SCORE,
           int2str(local_player->score, 5), FONT_TEXT_2);
   DrawText(DX + XX_TIME, DY + YY_TIME,
@@ -733,7 +743,7 @@ void DrawGameDoorValues()
 
 static void InitGameEngine()
 {
-  int i;
+  int i, j, k;
 
   /* set game engine from tape file when re-playing, else from level file */
   game.engine_version = (tape.playing ? tape.engine_version :
@@ -764,78 +774,82 @@ static void InitGameEngine()
   /* ---------- initialize changing elements ------------------------------- */
 
   /* initialize changing elements information */
-  for (i=0; i<MAX_NUM_ELEMENTS; i++)
+  for (i=0; i < MAX_NUM_ELEMENTS; i++)
   {
-#if 1
-    element_info[i].change.pre_change_function = NULL;
-    element_info[i].change.change_function = NULL;
-    element_info[i].change.post_change_function = NULL;
+    struct ElementInfo *ei = &element_info[i];
+
+    /* this pointer might have been changed in the level editor */
+    ei->change = &ei->change_page[0];
 
     if (!IS_CUSTOM_ELEMENT(i))
     {
-      element_info[i].change.target_element = EL_EMPTY_SPACE;
-      element_info[i].change.delay_fixed = 0;
-      element_info[i].change.delay_random = 0;
-      element_info[i].change.delay_frames = 1;
+      ei->change->target_element = EL_EMPTY_SPACE;
+      ei->change->delay_fixed = 0;
+      ei->change->delay_random = 0;
+      ei->change->delay_frames = 1;
     }
 
-    changing_element[i] = FALSE;
-#else
-    changing_element[i].base_element = EL_UNDEFINED;
-    changing_element[i].next_element = EL_UNDEFINED;
-    changing_element[i].change_delay = -1;
-    changing_element[i].pre_change_function = NULL;
-    changing_element[i].change_function = NULL;
-    changing_element[i].post_change_function = NULL;
-#endif
+    ei->change_events = CE_BITMASK_DEFAULT;
+    for (j=0; j < NUM_CHANGE_EVENTS; j++)
+    {
+      ei->event_page_num[j] = 0;
+      ei->event_page[j] = &ei->change_page[0];
+    }
   }
 
   /* add changing elements from pre-defined list */
-  for (i=0; changing_element_list[i].element != EL_UNDEFINED; i++)
+  for (i=0; change_delay_list[i].element != EL_UNDEFINED; i++)
   {
-    int element = changing_element_list[i].element;
-    struct ChangingElementInfo *ce = &changing_element_list[i];
-    struct ElementChangeInfo *change = &element_info[element].change;
+    struct ChangingElementInfo *ch_delay = &change_delay_list[i];
+    struct ElementInfo *ei = &element_info[ch_delay->element];
+
+    ei->change->target_element       = ch_delay->target_element;
+    ei->change->delay_fixed          = ch_delay->change_delay;
+
+    ei->change->pre_change_function  = ch_delay->pre_change_function;
+    ei->change->change_function      = ch_delay->change_function;
+    ei->change->post_change_function = ch_delay->post_change_function;
+
+    ei->change_events |= CH_EVENT_BIT(CE_DELAY);
+  }
 
 #if 1
-    change->target_element       = ce->target_element;
-    change->delay_fixed          = ce->change_delay;
-    change->pre_change_function  = ce->pre_change_function;
-    change->change_function      = ce->change_function;
-    change->post_change_function = ce->post_change_function;
+  /* add change events from custom element configuration */
+  for (i=0; i < NUM_CUSTOM_ELEMENTS; i++)
+  {
+    struct ElementInfo *ei = &element_info[EL_CUSTOM_START + i];
 
-    changing_element[element] = TRUE;
-#else
-    changing_element[element].base_element         = ce->base_element;
-    changing_element[element].next_element         = ce->next_element;
-    changing_element[element].change_delay         = ce->change_delay;
-    changing_element[element].pre_change_function  = ce->pre_change_function;
-    changing_element[element].change_function      = ce->change_function;
-    changing_element[element].post_change_function = ce->post_change_function;
-#endif
+    for (j=0; j < ei->num_change_pages; j++)
+    {
+      if (!ei->change_page[j].can_change)
+       continue;
+
+      for (k=0; k < NUM_CHANGE_EVENTS; k++)
+      {
+       /* only add event page for the first page found with this event */
+       if (ei->change_page[j].events & CH_EVENT_BIT(k) &&
+           !(ei->change_events & CH_EVENT_BIT(k)))
+       {
+         ei->change_events |= CH_EVENT_BIT(k);
+         ei->event_page_num[k] = j;
+         ei->event_page[k] = &ei->change_page[j];
+       }
+      }
+    }
   }
 
-  /* add changing elements from custom element configuration */
+#else
+
+  /* add change events from custom element configuration */
   for (i=0; i < NUM_CUSTOM_ELEMENTS; i++)
   {
     int element = EL_CUSTOM_START + i;
-#if 0
-    struct ElementChangeInfo *change = &element_info[element].change;
-#endif
 
     /* only add custom elements that change after fixed/random frame delay */
-    if (!CAN_CHANGE(element) || !HAS_CHANGE_EVENT(element, CE_DELAY))
-      continue;
-
-#if 1
-    changing_element[element] = TRUE;
-#else
-    changing_element[element].base_element = element;
-    changing_element[element].next_element = change->target_element;
-    changing_element[element].change_delay = (change->delay_fixed *
-                                             change->delay_frames);
-#endif
+    if (CAN_CHANGE(element) && HAS_CHANGE_EVENT(element, CE_DELAY))
+      element_info[element].change_events |= CH_EVENT_BIT(CE_DELAY);
   }
+#endif
 
   /* ---------- initialize trigger events ---------------------------------- */
 
@@ -843,11 +857,32 @@ static void InitGameEngine()
   for (i=0; i<MAX_NUM_ELEMENTS; i++)
     trigger_events[i] = EP_BITMASK_DEFAULT;
 
+#if 1
+  /* add trigger events from element change event properties */
+  for (i=0; i<MAX_NUM_ELEMENTS; i++)
+  {
+    struct ElementInfo *ei = &element_info[i];
+
+    for (j=0; j < ei->num_change_pages; j++)
+    {
+      if (!ei->change_page->can_change)
+       continue;
+
+      if (ei->change_page[j].events & CH_EVENT_BIT(CE_BY_OTHER))
+      {
+       int trigger_element = ei->change_page[j].trigger_element;
+
+       trigger_events[trigger_element] |= ei->change_page[j].events;
+      }
+    }
+  }
+#else
   /* add trigger events from element change event properties */
   for (i=0; i<MAX_NUM_ELEMENTS; i++)
     if (HAS_CHANGE_EVENT(i, CE_BY_OTHER))
-      trigger_events[element_info[i].change.trigger_element] |=
-       element_info[i].change.events;
+      trigger_events[element_info[i].change->trigger_element] |=
+       element_info[i].change->events;
+#endif
 
   /* ---------- initialize push delay -------------------------------------- */
 
@@ -890,12 +925,12 @@ static void InitGameEngine()
   /* initialize gem count values for each element */
   for (i=0; i<MAX_NUM_ELEMENTS; i++)
     if (!IS_CUSTOM_ELEMENT(i))
-      element_info[i].gem_count = 0;
+      element_info[i].collect_count = 0;
 
   /* add gem count values for all elements from pre-defined list */
-  for (i=0; gem_count_list[i].element != EL_UNDEFINED; i++)
-    element_info[gem_count_list[i].element].gem_count =
-      gem_count_list[i].gem_count;
+  for (i=0; collect_count_list[i].element != EL_UNDEFINED; i++)
+    element_info[collect_count_list[i].element].collect_count =
+      collect_count_list[i].count;
 }
 
 
@@ -952,7 +987,6 @@ void InitGame()
     for (j=0; j<4; j++)
       player->key[j] = FALSE;
 
-    player->dynamite = 0;
     player->dynabomb_count = 0;
     player->dynabomb_size = 1;
     player->dynabombs_left = 0;
@@ -994,6 +1028,8 @@ void InitGame()
     player->shield_normal_time_left = 0;
     player->shield_deadly_time_left = 0;
 
+    player->inventory_size = 0;
+
     DigField(player, 0, 0, 0, 0, DF_NO_PUSH);
     SnapField(player, 0, 0);
 
@@ -1206,16 +1242,107 @@ void InitGame()
   if (lev_fieldy + (SBY_Upper == -1 ? 2 : 0) <= SCR_FIELDY)
     SBY_Upper = SBY_Lower = -1 * (SCR_FIELDY - lev_fieldy) / 2;
 
-  scroll_x = SBX_Left;
-  scroll_y = SBY_Upper;
-  if (local_player->jx >= SBX_Left + MIDPOSX)
-    scroll_x = (local_player->jx <= SBX_Right + MIDPOSX ?
-               local_player->jx - MIDPOSX :
-               SBX_Right);
-  if (local_player->jy >= SBY_Upper + MIDPOSY)
-    scroll_y = (local_player->jy <= SBY_Lower + MIDPOSY ?
-               local_player->jy - MIDPOSY :
-               SBY_Lower);
+  /* if local player not found, look for custom element that might create
+     the player (make some assumptions about the right custom element) */
+  if (!local_player->present)
+  {
+    int start_x = 0, start_y = 0;
+    int found_rating = 0;
+    int found_element = EL_UNDEFINED;
+
+    for(y=0; y < lev_fieldy; y++) for(x=0; x < lev_fieldx; x++)
+    {
+      int element = Feld[x][y];
+      int content;
+      int xx, yy;
+      boolean is_player;
+
+      if (!IS_CUSTOM_ELEMENT(element))
+       continue;
+
+      if (CAN_CHANGE(element))
+      {
+       for (i=0; i < element_info[element].num_change_pages; i++)
+       {
+         content = element_info[element].change_page[i].target_element;
+         is_player = ELEM_IS_PLAYER(content);
+
+         if (is_player && (found_rating < 3 || element < found_element))
+         {
+           start_x = x;
+           start_y = y;
+
+           found_rating = 3;
+           found_element = element;
+         }
+       }
+      }
+
+      for(yy=0; yy < 3; yy++) for(xx=0; xx < 3; xx++)
+      {
+       content = element_info[element].content[xx][yy];
+       is_player = ELEM_IS_PLAYER(content);
+
+       if (is_player && (found_rating < 2 || element < found_element))
+       {
+         start_x = x + xx - 1;
+         start_y = y + yy - 1;
+
+         found_rating = 2;
+         found_element = element;
+       }
+
+       if (!CAN_CHANGE(element))
+         continue;
+
+       for (i=0; i < element_info[element].num_change_pages; i++)
+       {
+         content = element_info[element].change_page[i].content[xx][yy];
+         is_player = ELEM_IS_PLAYER(content);
+
+         if (is_player && (found_rating < 1 || element < found_element))
+         {
+           start_x = x + xx - 1;
+           start_y = y + yy - 1;
+
+           found_rating = 1;
+           found_element = element;
+         }
+       }
+      }
+    }
+
+    scroll_x = (start_x < SBX_Left  + MIDPOSX ? SBX_Left :
+               start_x > SBX_Right + MIDPOSX ? SBX_Right :
+               start_x - MIDPOSX);
+
+    scroll_y = (start_y < SBY_Upper + MIDPOSY ? SBY_Upper :
+               start_y > SBY_Lower + MIDPOSY ? SBY_Lower :
+               start_y - MIDPOSY);
+  }
+  else
+  {
+#if 1
+    scroll_x = (local_player->jx < SBX_Left  + MIDPOSX ? SBX_Left :
+               local_player->jx > SBX_Right + MIDPOSX ? SBX_Right :
+               local_player->jx - MIDPOSX);
+
+    scroll_y = (local_player->jy < SBY_Upper + MIDPOSY ? SBY_Upper :
+               local_player->jy > SBY_Lower + MIDPOSY ? SBY_Lower :
+               local_player->jy - MIDPOSY);
+#else
+    scroll_x = SBX_Left;
+    scroll_y = SBY_Upper;
+    if (local_player->jx >= SBX_Left + MIDPOSX)
+      scroll_x = (local_player->jx <= SBX_Right + MIDPOSX ?
+                 local_player->jx - MIDPOSX :
+                 SBX_Right);
+    if (local_player->jy >= SBY_Upper + MIDPOSY)
+      scroll_y = (local_player->jy <= SBY_Lower + MIDPOSY ?
+                 local_player->jy - MIDPOSY :
+                 SBY_Lower);
+#endif
+  }
 
   CloseDoor(DOOR_CLOSE_1);
 
@@ -1862,6 +1989,137 @@ void CheckDynamite(int x, int y)
   Bang(x, y);
 }
 
+void ShowEnvelope()
+{
+  int i, x, y;
+
+  /* open envelope window horizontally */
+  for (i=2; i <= level.envelope_xsize + 2; i += 2)
+  {
+    int startx = (SXSIZE / MINI_TILEX - i) / 2;
+    int starty = (SYSIZE / MINI_TILEY) / 2 - 1;
+
+    SetDrawtoField(DRAW_BUFFERED);
+
+    BlitBitmap(fieldbuffer, backbuffer, FX, FY, SXSIZE, SYSIZE, SX, SY);
+
+    SetDrawtoField(DRAW_BACKBUFFER);
+
+    for (y=0; y < 2; y++) for (x=0; x < i; x++)
+    {
+      int ex = (x == 0 ? -1 : x == i - 1 ? +1 : 0);
+      int ey = (y == 0 ? -1 : y == 1     ? +1 : 0);
+
+      DrawEnvelopeBorder(startx + x, starty + y, ex, ey);
+    }
+
+    redraw_mask |= REDRAW_FIELD | REDRAW_FROM_BACKBUFFER;
+    BackToFront();
+
+    Delay(GAME_FRAME_DELAY);
+  }
+
+  /* open envelope window vertically */
+  for (i=2; i <= level.envelope_ysize + 2; i += 2)
+  {
+    int xsize = level.envelope_xsize + 2;
+    int startx = (SXSIZE / MINI_TILEX - (xsize - 1)) / 2;
+    int starty = (SYSIZE / MINI_TILEY - i) / 2;
+
+    SetDrawtoField(DRAW_BUFFERED);
+
+    BlitBitmap(fieldbuffer, backbuffer, FX, FY, SXSIZE, SYSIZE, SX, SY);
+
+    SetDrawtoField(DRAW_BACKBUFFER);
+
+    for (y=0; y < i; y++) for (x=0; x < xsize; x++)
+    {
+      int ex = (x == 0 ? -1 : x == xsize - 1 ? +1 : 0);
+      int ey = (y == 0 ? -1 : y == i - 1     ? +1 : 0);
+
+      DrawEnvelopeBorder(startx + x, starty + y, ex, ey);
+    }
+
+    DrawTextToTextArea(SX + (startx + 1) * MINI_TILEX,
+                      SY + (starty + 1) * MINI_TILEY, level.envelope,
+                      FONT_TEXT_1, level.envelope_xsize, i - 2);
+
+    redraw_mask |= REDRAW_FIELD | REDRAW_FROM_BACKBUFFER;
+    BackToFront();
+
+    Delay(GAME_FRAME_DELAY);
+  }
+
+  Delay(3000);
+
+  SetDrawtoField(DRAW_BUFFERED);
+
+  redraw_mask |= REDRAW_FIELD;
+  BackToFront();
+}
+
+void RelocatePlayer(int x, int y, int element)
+{
+  struct PlayerInfo *player = &stored_player[element - EL_PLAYER_1];
+
+  if (player->present)
+  {
+    while (player->MovPos)
+    {
+      ScrollFigure(player, SCROLL_GO_ON);
+      ScrollScreen(NULL, SCROLL_GO_ON);
+      FrameCounter++;
+      DrawAllPlayers();
+      BackToFront();
+    }
+
+    RemoveField(player->jx, player->jy);
+    DrawLevelField(player->jx, player->jy);
+  }
+
+  InitPlayerField(x, y, element, TRUE);
+
+  if (player == local_player)
+  {
+    int scroll_xx = -999, scroll_yy = -999;
+
+    while (scroll_xx != scroll_x || scroll_yy != scroll_y)
+    {
+      int dx = 0, dy = 0;
+      int fx = FX, fy = FY;
+
+      scroll_xx = (local_player->jx < SBX_Left  + MIDPOSX ? SBX_Left :
+                  local_player->jx > SBX_Right + MIDPOSX ? SBX_Right :
+                  local_player->jx - MIDPOSX);
+
+      scroll_yy = (local_player->jy < SBY_Upper + MIDPOSY ? SBY_Upper :
+                  local_player->jy > SBY_Lower + MIDPOSY ? SBY_Lower :
+                  local_player->jy - MIDPOSY);
+
+      dx = (scroll_xx < scroll_x ? +1 : scroll_xx > scroll_x ? -1 : 0);
+      dy = (scroll_yy < scroll_y ? +1 : scroll_yy > scroll_y ? -1 : 0);
+
+      scroll_x -= dx;
+      scroll_y -= dy;
+
+      fx += dx * TILEX / 2;
+      fy += dy * TILEY / 2;
+
+      ScrollLevel(dx, dy);
+      DrawAllPlayers();
+
+      /* scroll in to steps of half tile size to make things smoother */
+      BlitBitmap(drawto_field, window, fx, fy, SXSIZE, SYSIZE, SX, SY);
+      FlushDisplay();
+      Delay(GAME_FRAME_DELAY);
+
+      /* scroll second step to align at full tile size */
+      BackToFront();
+      Delay(GAME_FRAME_DELAY);
+    }
+  }
+}
+
 void Explode(int ex, int ey, int phase, int mode)
 {
   int x, y;
@@ -1893,7 +2151,7 @@ void Explode(int ex, int ey, int phase, int mode)
       PlaySoundLevelAction(ex, ey, ACTION_EXPLODING);
 
     /* remove things displayed in background while burning dynamite */
-    if (!IS_INDESTRUCTIBLE(Back[ex][ey]))
+    if (Back[ex][ey] != EL_EMPTY && !IS_INDESTRUCTIBLE(Back[ex][ey]))
       Back[ex][ey] = 0;
 
     if (IS_MOVING(ex, ey) || IS_BLOCKED(ex, ey))
@@ -1927,7 +2185,7 @@ void Explode(int ex, int ey, int phase, int mode)
 
 #if 1
 
-#if 1
+#if 0
       if (IS_EXPLOSION_PROOF(element))
        continue;
 #else
@@ -1958,11 +2216,11 @@ void Explode(int ex, int ey, int phase, int mode)
       }
 
       /* save walkable background elements while explosion on same tile */
-#if 1
+#if 0
       if (IS_INDESTRUCTIBLE(element))
        Back[x][y] = element;
 #else
-      if (IS_INDESTRUCTIBLE(element) && IS_WALKABLE(element))
+      if (IS_WALKABLE(element) && IS_INDESTRUCTIBLE(element))
        Back[x][y] = element;
 #endif
 
@@ -2038,7 +2296,7 @@ void Explode(int ex, int ey, int phase, int mode)
        Store[x][y] = EL_PEARL;
       else if (element == EL_WALL_CRYSTAL)
        Store[x][y] = EL_CRYSTAL;
-      else if (IS_CUSTOM_ELEMENT(element))
+      else if (IS_CUSTOM_ELEMENT(element) && !CAN_EXPLODE(element))
        Store[x][y] = element_info[element].content[1][1];
       else
        Store[x][y] = EL_EMPTY;
@@ -2136,8 +2394,14 @@ void Explode(int ex, int ey, int phase, int mode)
       InitMovDir(x, y);
     DrawLevelField(x, y);
 
+    if (CAN_BE_CRUMBLED(element))
+      DrawLevelFieldCrumbledSandNeighbours(x, y);
+
     if (IS_PLAYER(x, y) && !PLAYERINFO(x,y)->present)
       StorePlayer[x][y] = 0;
+
+    if (ELEM_IS_PLAYER(element))
+      RelocatePlayer(x, y, element);
   }
   else if (phase >= delay && IN_SCR_FIELD(SCREENX(x), SCREENY(y)))
   {
@@ -2212,6 +2476,7 @@ void DynaExplode(int ex, int ey)
 
       Explode(x, y, EX_PHASE_START, EX_BORDER);
 
+      /* !!! extend EL_SAND to anything diggable (but maybe not SP_BASE) !!! */
       if (element != EL_EMPTY &&
          element != EL_SAND &&
          element != EL_EXPLOSION &&
@@ -2285,7 +2550,10 @@ void Bang(int x, int y)
        Explode(x, y, EX_PHASE_START, EX_CENTER);
       break;
     default:
-      Explode(x, y, EX_PHASE_START, EX_NORMAL);
+      if (CAN_EXPLODE_1X1(element))
+       Explode(x, y, EX_PHASE_START, EX_CENTER);
+      else
+       Explode(x, y, EX_PHASE_START, EX_NORMAL);
       break;
   }
 
@@ -2522,14 +2790,16 @@ static int getInvisibleActiveFromInvisibleElement(int element)
 {
   return (element == EL_INVISIBLE_STEELWALL ? EL_INVISIBLE_STEELWALL_ACTIVE :
          element == EL_INVISIBLE_WALL      ? EL_INVISIBLE_WALL_ACTIVE :
-         EL_INVISIBLE_SAND_ACTIVE);
+         element == EL_INVISIBLE_SAND      ? EL_INVISIBLE_SAND_ACTIVE :
+         element);
 }
 
 static int getInvisibleFromInvisibleActiveElement(int element)
 {
   return (element == EL_INVISIBLE_STEELWALL_ACTIVE ? EL_INVISIBLE_STEELWALL :
          element == EL_INVISIBLE_WALL_ACTIVE      ? EL_INVISIBLE_WALL :
-         EL_INVISIBLE_SAND);
+         element == EL_INVISIBLE_SAND_ACTIVE      ? EL_INVISIBLE_SAND :
+         element);
 }
 
 static void RedrawAllLightSwitchesAndInvisibleElements()
@@ -2677,7 +2947,9 @@ void Impact(int x, int y)
     return;
   }
 
-  if (impact)
+  /* only reset graphic animation if graphic really changes after impact */
+  if (impact &&
+      el_act_dir2img(element, GfxAction[x][y], MV_DOWN) != el2img(element))
   {
     ResetGfxAnimation(x, y);
     DrawLevelField(x, y);
@@ -2694,24 +2966,12 @@ void Impact(int x, int y)
     PlaySoundLevel(x, y, SND_PEARL_BREAKING);
     return;
   }
-#if 1
-  else if (impact && CheckElementChange(x, y, element, ACTION_IMPACT))
-  {
-    PlaySoundLevelElementAction(x, y, element, ACTION_IMPACT);
-
-    return;
-  }
-#else
-  else if (impact && CAN_CHANGE(element) &&
-          HAS_CHANGE_EVENT(element, CE_IMPACT))
+  else if (impact && CheckElementChange(x, y, element, CE_IMPACT))
   {
     PlaySoundLevelElementAction(x, y, element, ACTION_IMPACT);
 
-    ChangeElementNow(x, y, element);
-
     return;
   }
-#endif
 
   if (impact && element == EL_AMOEBA_DROP)
   {
@@ -2843,17 +3103,10 @@ void Impact(int x, int y)
        {
          ToggleLightSwitch(x, y + 1);
        }
-#if 1
        else
        {
          CheckElementChange(x, y + 1, smashed, CE_SMASHED);
        }
-#else
-       else if (CAN_CHANGE(smashed) && HAS_CHANGE_EVENT(smashed, CE_SMASHED))
-       {
-         ChangeElementNow(x, y + 1, smashed);
-       }
-#endif
       }
       else
       {
@@ -3449,7 +3702,8 @@ void StartMoving(int x, int y)
 
   if (CAN_FALL(element) && y < lev_fieldy - 1)
   {
-    if ((x>0 && IS_PLAYER(x-1, y)) || (x<lev_fieldx-1 && IS_PLAYER(x+1, y)))
+    if ((x > 0 && IS_PLAYER(x - 1, y)) ||
+       (x < lev_fieldx-1 && IS_PLAYER(x + 1, y)))
       if (JustBeingPushed(x, y))
        return;
 
@@ -3840,14 +4094,18 @@ void StartMoving(int x, int y)
        return;
       }
 
-      GfxAction[x][y] = ACTION_MOVING;
+      /* special case of "moving" animation of waiting elements (FIX THIS !!!);
+        for all other elements GfxAction will be set by InitMovingField() */
+      if (element == EL_BD_BUTTERFLY || element == EL_BD_FIREFLY)
+       GfxAction[x][y] = ACTION_MOVING;
     }
 
     /* now make next step */
 
     Moving2Blocked(x, y, &newx, &newy);        /* get next screen position */
 
-    if (DONT_COLLIDE_WITH(element) && IS_PLAYER(newx, newy) &&
+    if (DONT_COLLIDE_WITH(element) &&
+       IN_LEV_FIELD(newx, newy) && IS_PLAYER(newx, newy) &&
        !PLAYER_PROTECTED(newx, newy))
     {
 #if 1
@@ -4053,7 +4311,8 @@ void StartMoving(int x, int y)
       TurnRound(x, y);
 
 #if 1
-      DrawLevelElementAnimation(x, y, element);
+      if (GFX_ELEMENT(element) != EL_SAND)     /* !!! FIX THIS (crumble) !!! */
+       DrawLevelElementAnimation(x, y, element);
 #else
       if (element == EL_BUG ||
          element == EL_SPACESHIP ||
@@ -4547,6 +4806,7 @@ void AmoebeAbleger(int ax, int ay)
     if (!IN_LEV_FIELD(x, y))
       return;
 
+    /* !!! extend EL_SAND to anything diggable (but maybe not SP_BASE) !!! */
     if (IS_FREE(x, y) ||
        Feld[x][y] == EL_SAND || Feld[x][y] == EL_QUICKSAND_EMPTY)
     {
@@ -4571,6 +4831,7 @@ void AmoebeAbleger(int ax, int ay)
       if (!IN_LEV_FIELD(x, y))
        continue;
 
+      /* !!! extend EL_SAND to anything diggable (but maybe not SP_BASE) !!! */
       if (IS_FREE(x, y) ||
          Feld[x][y] == EL_SAND || Feld[x][y] == EL_QUICKSAND_EMPTY)
       {
@@ -4715,6 +4976,7 @@ void Life(int ax, int ay)
        changed = TRUE;
       }
     }
+    /* !!! extend EL_SAND to anything diggable (but maybe not SP_BASE) !!! */
     else if (IS_FREE(xx, yy) || Feld[xx][yy] == EL_SAND)
     {                                  /* free border field */
       if (nachbarn >= life[2] && nachbarn <= life[3])
@@ -5132,7 +5394,10 @@ static void ChangeActiveTrap(int x, int y)
 
 static void ChangeElementNowExt(int x, int y, int target_element)
 {
-  if (IS_PLAYER(x, y) && !IS_ACCESSIBLE(target_element))
+  /* check if element under player changes from accessible to unaccessible
+     (needed for special case of dropping element which then changes) */
+  if (IS_PLAYER(x, y) && !PLAYER_PROTECTED(x, y) &&
+      IS_ACCESSIBLE(Feld[x][y]) && !IS_ACCESSIBLE(target_element))
   {
     Bang(x, y);
     return;
@@ -5156,19 +5421,17 @@ static void ChangeElementNowExt(int x, int y, int target_element)
   TestIfBadThingTouchesHero(x, y);
   TestIfPlayerTouchesCustomElement(x, y);
   TestIfElementTouchesCustomElement(x, y);
+
+  if (ELEM_IS_PLAYER(target_element))
+    RelocatePlayer(x, y, target_element);
 }
 
-static void ChangeElementNow(int x, int y, int element)
+static void ChangeElementNow(int x, int y, int element, int page)
 {
-  struct ElementChangeInfo *change = &element_info[element].change;
-
-  /* prevent CheckTriggeredElementChange() from looping */
-  Changing[x][y] = TRUE;
+  struct ElementChangeInfo *change = &element_info[element].change_page[page];
 
   CheckTriggeredElementChange(x, y, Feld[x][y], CE_OTHER_IS_CHANGING);
 
-  Changing[x][y] = FALSE;
-
   if (change->explode)
   {
     Bang(x, y);
@@ -5226,6 +5489,8 @@ static void ChangeElementNow(int x, int y, int element)
 
     if (!change->only_complete || complete_change)
     {
+      boolean something_has_changed = FALSE;
+
       if (change->only_complete && change->use_random_change &&
          RND(100) < change->random)
        return;
@@ -5243,55 +5508,41 @@ static void ChangeElementNow(int x, int y, int element)
 
          ChangeElementNowExt(ex, ey, change->content[xx][yy]);
 
+         something_has_changed = TRUE;
+
          /* for symmetry reasons, stop newly created border elements */
          if (ex != x || ey != y)
            Stop[ex][ey] = TRUE;
        }
       }
 
-      return;
+      if (something_has_changed)
+       PlaySoundLevelElementAction(x, y, element, ACTION_CHANGING);
     }
   }
+  else
+  {
+    ChangeElementNowExt(x, y, change->target_element);
 
-  ChangeElementNowExt(x, y, change->target_element);
+    PlaySoundLevelElementAction(x, y, element, ACTION_CHANGING);
+  }
 }
 
-static void ChangeElement(int x, int y)
+static void ChangeElement(int x, int y, int page)
 {
-#if 1
   int element = MovingOrBlocked2Element(x, y);
-#else
-  int element = Feld[x][y];
-#endif
-  struct ElementChangeInfo *change = &element_info[element].change;
+  struct ElementChangeInfo *change = &element_info[element].change_page[page];
 
   if (ChangeDelay[x][y] == 0)          /* initialize element change */
   {
-#if 1
     ChangeDelay[x][y] = (    change->delay_fixed  * change->delay_frames +
                         RND(change->delay_random * change->delay_frames)) + 1;
-#else
-    ChangeDelay[x][y] = changing_element[element].change_delay + 1;
-
-    if (IS_CUSTOM_ELEMENT(element) && HAS_CHANGE_EVENT(element, CE_DELAY))
-    {
-      int max_random_delay = element_info[element].change.delay_random;
-      int delay_frames = element_info[element].change.delay_frames;
-
-      ChangeDelay[x][y] += RND(max_random_delay * delay_frames);
-    }
-#endif
 
     ResetGfxAnimation(x, y);
     ResetRandomAnimationValue(x, y);
 
-#if 1
     if (change->pre_change_function)
       change->pre_change_function(x, y);
-#else
-    if (changing_element[element].pre_change_function)
-      changing_element[element].pre_change_function(x, y);
-#endif
   }
 
   ChangeDelay[x][y]--;
@@ -5303,20 +5554,11 @@ static void ChangeElement(int x, int y)
     if (IS_ANIMATED(graphic))
       DrawLevelGraphicAnimationIfNeeded(x, y, graphic);
 
-#if 1
     if (change->change_function)
       change->change_function(x, y);
-#else
-    if (changing_element[element].change_function)
-      changing_element[element].change_function(x, y);
-#endif
   }
   else                                 /* finish element change */
   {
-#if 0
-    int next_element = changing_element[element].next_element;
-#endif
-
     if (IS_MOVING(x, y))               /* never change a running system ;-) */
     {
       ChangeDelay[x][y] = 1;           /* try change after next move step */
@@ -5324,37 +5566,59 @@ static void ChangeElement(int x, int y)
       return;
     }
 
-#if 1
-    ChangeElementNow(x, y, element);
+    ChangeElementNow(x, y, element, page);
 
     if (change->post_change_function)
       change->post_change_function(x, y);
-#else
-    if (next_element != EL_UNDEFINED)
-      ChangeElementNow(x, y, next_element);
-    else
-      ChangeElementNow(x, y, element_info[element].change.target_element);
-
-    if (changing_element[element].post_change_function)
-      changing_element[element].post_change_function(x, y);
-#endif
   }
 }
 
 static boolean CheckTriggeredElementChange(int lx, int ly, int trigger_element,
                                           int trigger_event)
 {
-  int i, x, y;
+  int i, j, x, y;
 
   if (!(trigger_events[trigger_element] & CH_EVENT_BIT(trigger_event)))
     return FALSE;
 
-  for (i=0; i<MAX_NUM_ELEMENTS; i++)
+  /* prevent this function from running into a loop */
+  if (trigger_event == CE_OTHER_IS_CHANGING)
+    Changing[lx][ly] = TRUE;
+
+  for (i=0; i < NUM_CUSTOM_ELEMENTS; i++)
   {
-    if (!CAN_CHANGE(i) || !HAS_CHANGE_EVENT(i, trigger_event) ||
-       element_info[i].change.trigger_element != trigger_element)
+    int element = EL_CUSTOM_START + i;
+
+#if 1
+    boolean change_element = FALSE;
+    int page;
+
+    if (!CAN_CHANGE(element) ||
+       !HAS_ANY_CHANGE_EVENT(element, trigger_event))
+      continue;
+
+    for (j=0; j < element_info[element].num_change_pages; j++)
+    {
+      if (element_info[element].change_page[j].trigger_element ==
+         trigger_element)
+      {
+       change_element = TRUE;
+       page = j;
+
+       break;
+      }
+    }
+
+    if (!change_element)
       continue;
 
+#else
+    if (!CAN_CHANGE(element) ||
+       !HAS_ANY_CHANGE_EVENT(element, trigger_event) ||
+       element_info[element].change->trigger_element != trigger_element)
+      continue;
+#endif
+
     for (y=0; y<lev_fieldy; y++) for (x=0; x<lev_fieldx; x++)
     {
       if (x == lx && y == ly)  /* do not change trigger element itself */
@@ -5363,36 +5627,50 @@ static boolean CheckTriggeredElementChange(int lx, int ly, int trigger_element,
       if (Changing[x][y])      /* do not change just changing elements */
        continue;
 
-      if (Feld[x][y] == i)
+      if (Feld[x][y] == element)
       {
        ChangeDelay[x][y] = 1;
-       ChangeElement(x, y);
+       ChangeElement(x, y, page);
+
+       Changing[x][y] = TRUE;  /* do not change just changed elements */
       }
     }
   }
 
+  /* reset change prevention array */
+  for (y=0; y<lev_fieldy; y++) for (x=0; x<lev_fieldx; x++)
+    Changing[x][y] = FALSE;
+
   return TRUE;
 }
 
-static boolean CheckElementChange(int x, int y, int element, int trigger_event)
+static boolean CheckElementChangeExt(int x, int y, int element,
+                                    int trigger_event, int page)
 {
-  if (!CAN_CHANGE(element) || !HAS_CHANGE_EVENT(element, trigger_event))
+  if (!CAN_CHANGE(element) || !HAS_ANY_CHANGE_EVENT(element, trigger_event))
     return FALSE;
 
   if (Feld[x][y] == EL_BLOCKED)
     Blocked2Moving(x, y, &x, &y);
 
   ChangeDelay[x][y] = 1;
-  ChangeElement(x, y);
+  ChangeElement(x, y, page);
 
   return TRUE;
 }
 
+static boolean CheckElementChange(int x, int y, int element, int trigger_event)
+{
+  int page = element_info[element].event_page_num[trigger_event];
+
+  return CheckElementChangeExt(x, y, element, trigger_event, page);
+}
+
 static void PlayerActions(struct PlayerInfo *player, byte player_action)
 {
   static byte stored_player_action[MAX_PLAYERS];
   static int num_stored_actions = 0;
-  boolean moved = FALSE, snapped = FALSE, bombed = FALSE;
+  boolean moved = FALSE, snapped = FALSE, dropped = FALSE;
   int left     = player_action & JOY_LEFT;
   int right    = player_action & JOY_RIGHT;
   int up       = player_action & JOY_UP;
@@ -5415,13 +5693,14 @@ static void PlayerActions(struct PlayerInfo *player, byte player_action)
     else
     {
       if (button2)
-       bombed = PlaceBomb(player);
+       dropped = DropElement(player);
+
       moved = MoveFigure(player, dx, dy);
     }
 
     if (tape.single_step && tape.recording && !tape.pausing)
     {
-      if (button1 || (bombed && !moved))
+      if (button1 || (dropped && !moved))
       {
        TapeTogglePause(TAPE_TOGGLE_AUTOMATIC);
        SnapField(player, 0, 0);                /* stop snapping */
@@ -5439,13 +5718,7 @@ static void PlayerActions(struct PlayerInfo *player, byte player_action)
     CheckGravityMovement(player);
 
     if (player->MovPos == 0)
-    {
-#if 0
-      printf("Trying... Player frame reset\n");
-#endif
-
       InitPlayerGfxAnimation(player, ACTION_DEFAULT, player->MovDir);
-    }
 
     if (player->MovPos == 0)   /* needed for tape.playing */
       player->is_moving = FALSE;
@@ -5656,7 +5929,7 @@ void GameActions()
     /* this may take place after moving, so 'element' may have changed */
     if (IS_CHANGING(x, y))
     {
-      ChangeElement(x, y);
+      ChangeElement(x, y, element_info[element].event_page_num[CE_DELAY]);
       element = Feld[x][y];
       graphic = el_act_dir2img(element, GfxAction[x][y], MovDir[x][y]);
     }
@@ -5795,6 +6068,7 @@ void GameActions()
 #endif
       element = Feld[x][y];
 
+      /* !!! extend EL_SAND to anything diggable (but maybe not SP_BASE) !!! */
       if (!IS_PLAYER(x,y) &&
          (element == EL_EMPTY ||
           element == EL_SAND ||
@@ -6038,24 +6312,24 @@ void ScrollLevel(int dx, int dy)
   int x, y;
 
   BlitBitmap(drawto_field, drawto_field,
-            FX + TILEX*(dx == -1) - softscroll_offset,
-            FY + TILEY*(dy == -1) - softscroll_offset,
-            SXSIZE - TILEX*(dx!=0) + 2*softscroll_offset,
-            SYSIZE - TILEY*(dy!=0) + 2*softscroll_offset,
-            FX + TILEX*(dx == 1) - softscroll_offset,
-            FY + TILEY*(dy == 1) - softscroll_offset);
+            FX + TILEX * (dx == -1) - softscroll_offset,
+            FY + TILEY * (dy == -1) - softscroll_offset,
+            SXSIZE - TILEX * (dx!=0) + 2 * softscroll_offset,
+            SYSIZE - TILEY * (dy!=0) + 2 * softscroll_offset,
+            FX + TILEX * (dx == 1) - softscroll_offset,
+            FY + TILEY * (dy == 1) - softscroll_offset);
 
   if (dx)
   {
     x = (dx == 1 ? BX1 : BX2);
-    for (y=BY1; y<=BY2; y++)
+    for (y=BY1; y <= BY2; y++)
       DrawScreenField(x, y);
   }
 
   if (dy)
   {
     y = (dy == 1 ? BY1 : BY2);
-    for (x=BX1; x<=BX2; x++)
+    for (x=BX1; x <= BX2; x++)
       DrawScreenField(x, y);
   }
 
@@ -6082,6 +6356,7 @@ static void CheckGravityMovement(struct PlayerInfo *player)
       (IN_LEV_FIELD(new_jx, new_jy) &&
        (Feld[new_jx][new_jy] == EL_SP_BASE ||
        Feld[new_jx][new_jy] == EL_SAND));
+    /* !!! extend EL_SAND to anything diggable !!! */
 
     if (field_under_player_is_free &&
        !player_is_moving_to_valid_field &&
@@ -6146,6 +6421,10 @@ boolean MoveFigureOneStep(struct PlayerInfo *player,
   if (can_move != MF_MOVING)
     return can_move;
 
+  /* check if DigField() has caused relocation of the player */
+  if (player->jx != jx || player->jy != jy)
+    return MF_NO_ACTION;
+
   StorePlayer[jx][jy] = 0;
   player->last_jx = jx;
   player->last_jy = jy;
@@ -6315,6 +6594,9 @@ boolean MoveFigure(struct PlayerInfo *player, int dx, int dy)
 
     player->last_move_dir = player->MovDir;
     player->is_moving = TRUE;
+#if 1
+    player->snapped = FALSE;
+#endif
   }
   else
   {
@@ -6391,6 +6673,7 @@ void ScrollFigure(struct PlayerInfo *player, int mode)
     if (Feld[jx][jy] == EL_EXIT_OPEN ||
        Feld[jx][jy] == EL_SP_EXIT_OPEN)
     {
+      DrawPlayer(player);      /* needed here only to cleanup last field */
       RemoveHero(player);
 
       if (local_player->friends_still_needed == 0 ||
@@ -6442,11 +6725,9 @@ void TestIfPlayerTouchesCustomElement(int x, int y)
     { +1, 0 },
     { 0, +1 }
   };
-  boolean center_is_player = (IS_PLAYER(x, y));
   int i;
 
-  /* prevent TestIfPlayerTouchesCustomElement() from looping */
-  if (check_changing)
+  if (check_changing)  /* prevent this function from running into a loop */
     return;
 
   check_changing = TRUE;
@@ -6459,7 +6740,7 @@ void TestIfPlayerTouchesCustomElement(int x, int y)
     if (!IN_LEV_FIELD(xx, yy))
       continue;
 
-    if (center_is_player)
+    if (IS_PLAYER(x, y))
     {
       CheckTriggeredElementChange(xx, yy, Feld[xx][yy], CE_OTHER_GETS_TOUCHED);
       CheckElementChange(xx, yy, Feld[xx][yy], CE_TOUCHED_BY_PLAYER);
@@ -6486,11 +6767,12 @@ void TestIfElementTouchesCustomElement(int x, int y)
     { +1, 0 },
     { 0, +1 }
   };
-  boolean center_is_custom = (IS_CUSTOM_ELEMENT(Feld[x][y]));
-  int i;
+  boolean change_center_element = FALSE;
+  int center_element_change_page = 0;
+  int center_element = Feld[x][y];
+  int i, j;
 
-  /* prevent TestIfElementTouchesCustomElement() from looping */
-  if (check_changing)
+  if (check_changing)  /* prevent this function from running into a loop */
     return;
 
   check_changing = TRUE;
@@ -6499,23 +6781,57 @@ void TestIfElementTouchesCustomElement(int x, int y)
   {
     int xx = x + xy[i][0];
     int yy = y + xy[i][1];
+    int border_element;
 
     if (!IN_LEV_FIELD(xx, yy))
       continue;
 
-    if (center_is_custom &&
-       Feld[xx][yy] == element_info[Feld[x][y]].change.trigger_element)
+    border_element = Feld[xx][yy];
+
+    /* check for change of center element (but change it only once) */
+    if (IS_CUSTOM_ELEMENT(center_element) &&
+       HAS_ANY_CHANGE_EVENT(center_element, CE_OTHER_IS_TOUCHING) &&
+       !change_center_element)
     {
-      CheckElementChange(x, y, Feld[x][y], CE_OTHER_IS_TOUCHING);
+      for (j=0; j < element_info[center_element].num_change_pages; j++)
+      {
+       struct ElementChangeInfo *change =
+         &element_info[center_element].change_page[j];
+
+       if (change->events & CH_EVENT_BIT(CE_OTHER_IS_TOUCHING) &&
+           change->trigger_element == border_element)
+       {
+         change_center_element = TRUE;
+         center_element_change_page = j;
+
+         break;
+       }
+      }
     }
 
-    if (IS_CUSTOM_ELEMENT(Feld[xx][yy]) &&
-       Feld[x][y] == element_info[Feld[xx][yy]].change.trigger_element)
+    /* check for change of border element */
+    if (IS_CUSTOM_ELEMENT(border_element) &&
+       HAS_ANY_CHANGE_EVENT(border_element, CE_OTHER_IS_TOUCHING))
     {
-      CheckElementChange(xx, yy, Feld[xx][yy], CE_OTHER_IS_TOUCHING);
+      for (j=0; j < element_info[border_element].num_change_pages; j++)
+      {
+       struct ElementChangeInfo *change =
+         &element_info[border_element].change_page[j];
+
+       if (change->events & CH_EVENT_BIT(CE_OTHER_IS_TOUCHING) &&
+           change->trigger_element == center_element)
+       {
+         CheckElementChangeExt(xx,yy, border_element,CE_OTHER_IS_TOUCHING, j);
+         break;
+       }
+      }
     }
   }
 
+  if (change_center_element)
+    CheckElementChangeExt(x, y, center_element, CE_OTHER_IS_TOUCHING,
+                         center_element_change_page);
+
   check_changing = FALSE;
 }
 
@@ -7057,6 +7373,12 @@ int DigField(struct PlayerInfo *player,
          !IS_FREE(nextx, nexty))
        return MF_NO_ACTION;
 
+      if (element == EL_SP_GRAVITY_PORT_LEFT ||
+         element == EL_SP_GRAVITY_PORT_RIGHT ||
+         element == EL_SP_GRAVITY_PORT_UP ||
+         element == EL_SP_GRAVITY_PORT_DOWN)
+       level.gravity = !level.gravity;
+
       /* automatically move to the next field with double speed */
       player->programmed_action = move_direction;
       DOUBLE_PLAYER_SPEED(player);
@@ -7187,8 +7509,12 @@ int DigField(struct PlayerInfo *player,
 
        if (mode != DF_SNAP)
        {
+#if 1
+         GfxElement[x][y] = GFX_ELEMENT(element);
+#else
          GfxElement[x][y] =
            (CAN_BE_CRUMBLED(element) ? EL_SAND : GFX_ELEMENT(element));
+#endif
          player->is_digging = TRUE;
        }
 
@@ -7221,11 +7547,13 @@ int DigField(struct PlayerInfo *player,
        }
        else if (element == EL_DYNAMITE || element == EL_SP_DISK_RED)
        {
-         player->dynamite++;
+         if (player->inventory_size < MAX_INVENTORY_SIZE)
+           player->inventory_element[player->inventory_size++] = element;
+
          player->use_disk_red_graphic = (element == EL_SP_DISK_RED);
 
          DrawText(DX_DYNAMITE, DY_DYNAMITE,
-                  int2str(local_player->dynamite, 3), FONT_TEXT_2);
+                  int2str(local_player->inventory_size, 3), FONT_TEXT_2);
        }
        else if (element == EL_DYNABOMB_INCREASE_NUMBER)
        {
@@ -7252,10 +7580,25 @@ int DigField(struct PlayerInfo *player,
                             el2edimg(EL_KEY_1 + key_nr));
          redraw_mask |= REDRAW_DOOR_1;
        }
-       else if (element_info[element].gem_count > 0)
+       else if (element == EL_ENVELOPE)
+       {
+         ShowEnvelope();
+       }
+       else if (IS_DROPPABLE(element)) /* can be collected and dropped */
+       {
+         int i;
+
+         for (i=0; i < element_info[element].collect_count; i++)
+           if (player->inventory_size < MAX_INVENTORY_SIZE)
+             player->inventory_element[player->inventory_size++] = element;
+
+         DrawText(DX_DYNAMITE, DY_DYNAMITE,
+                  int2str(local_player->inventory_size, 3), FONT_TEXT_2);
+       }
+       else if (element_info[element].collect_count > 0)
        {
          local_player->gems_still_needed -=
-           element_info[element].gem_count;
+           element_info[element].collect_count;
          if (local_player->gems_still_needed < 0)
            local_player->gems_still_needed = 0;
 
@@ -7408,8 +7751,15 @@ boolean SnapField(struct PlayerInfo *player, int dx, int dy)
     {
       player->is_digging = FALSE;
       player->is_collecting = FALSE;
+#if 1
+      player->is_moving = FALSE;
+#endif
     }
 
+#if 0
+    printf("::: trying to snap...\n");
+#endif
+
     return FALSE;
   }
 
@@ -7418,12 +7768,25 @@ boolean SnapField(struct PlayerInfo *player, int dx, int dy)
 
   player->MovDir = snap_direction;
 
+#if 1
+  player->is_digging = FALSE;
+  player->is_collecting = FALSE;
+#if 1
+  player->is_moving = FALSE;
+#endif
+#endif
+
   if (DigField(player, x, y, 0, 0, DF_SNAP) == MF_NO_ACTION)
     return FALSE;
 
   player->snapped = TRUE;
+#if 1
   player->is_digging = FALSE;
   player->is_collecting = FALSE;
+#if 1
+  player->is_moving = FALSE;
+#endif
+#endif
 
   DrawLevelField(x, y);
   BackToFront();
@@ -7431,66 +7794,68 @@ boolean SnapField(struct PlayerInfo *player, int dx, int dy)
   return TRUE;
 }
 
-boolean PlaceBomb(struct PlayerInfo *player)
+boolean DropElement(struct PlayerInfo *player)
 {
   int jx = player->jx, jy = player->jy;
-  int element;
+  int old_element;
 
   if (!player->active || player->MovPos)
     return FALSE;
 
-  element = Feld[jx][jy];
+  old_element = Feld[jx][jy];
 
-  if ((player->dynamite == 0 && player->dynabombs_left == 0) ||
-      IS_ACTIVE_BOMB(element) || element == EL_EXPLOSION)
+  /* check if player has anything that can be dropped */
+  if (player->inventory_size == 0 && player->dynabombs_left == 0)
     return FALSE;
 
-#if 0
-  if (element != EL_EMPTY)
+  /* check if anything can be dropped at the current position */
+  if (IS_ACTIVE_BOMB(old_element) || old_element == EL_EXPLOSION)
     return FALSE;
-#endif
 
-  if (element != EL_EMPTY)
-  {
-#if 0
-    Store[jx][jy] = element;
-#else
-    Back[jx][jy] = element;
-#endif
-  }
+  /* collected custom elements can only be dropped on empty fields */
+  if (player->inventory_size > 0 &&
+      IS_CUSTOM_ELEMENT(player->inventory_element[player->inventory_size - 1])
+      && old_element != EL_EMPTY)
+    return FALSE;
+
+  if (old_element != EL_EMPTY)
+    Back[jx][jy] = old_element;                /* store old element on this field */
 
   MovDelay[jx][jy] = 96;
 
   ResetGfxAnimation(jx, jy);
   ResetRandomAnimationValue(jx, jy);
 
-  if (player->dynamite)
+  if (player->inventory_size > 0)
   {
+    int new_element = player->inventory_element[--player->inventory_size];
+
+#if 1
+    Feld[jx][jy] = (new_element == EL_DYNAMITE ? EL_DYNAMITE_ACTIVE :
+                   new_element == EL_SP_DISK_RED ? EL_SP_DISK_RED_ACTIVE :
+                   new_element);
+#else
     Feld[jx][jy] = (player->use_disk_red_graphic ? EL_SP_DISK_RED_ACTIVE :
                    EL_DYNAMITE_ACTIVE);
-    player->dynamite--;
+#endif
+
+    DrawText(DX_DYNAMITE, DY_DYNAMITE,
+            int2str(local_player->inventory_size, 3), FONT_TEXT_2);
 
-    DrawText(DX_DYNAMITE, DY_DYNAMITE, int2str(local_player->dynamite, 3),
-            FONT_TEXT_2);
     if (IN_SCR_FIELD(SCREENX(jx), SCREENY(jy)))
-    {
-#if 1
       DrawGraphicThruMask(SCREENX(jx), SCREENY(jy), el2img(Feld[jx][jy]), 0);
-#else
-      if (game.emulation == EMU_SUPAPLEX)
-       DrawGraphic(SCREENX(jx), SCREENY(jy), IMG_SP_DISK_RED, 0);
-      else
-       DrawGraphicThruMask(SCREENX(jx), SCREENY(jy), IMG_DYNAMITE_ACTIVE, 0);
-#endif
-    }
 
     PlaySoundLevelAction(jx, jy, ACTION_DROPPING);
+
+    CheckTriggeredElementChange(jx, jy, new_element, CE_OTHER_GETS_DROPPED);
+    CheckElementChange(jx, jy, new_element, CE_DROPPED_BY_PLAYER);
   }
-  else
+  else         /* player is dropping a dyna bomb */
   {
+    player->dynabombs_left--;
+
     Feld[jx][jy] =
       EL_DYNABOMB_PLAYER_1_ACTIVE + (player->element_nr - EL_PLAYER_1);
-    player->dynabombs_left--;
 
     if (IN_SCR_FIELD(SCREENX(jx), SCREENY(jy)))
       DrawGraphicThruMask(SCREENX(jx), SCREENY(jy), el2img(Feld[jx][jy]), 0);
@@ -7676,7 +8041,7 @@ void RaiseScoreElement(int element)
       RaiseScore(level.score[SC_KEY]);
       break;
     default:
-      RaiseScore(element_info[element].score);
+      RaiseScore(element_info[element].collect_score);
       break;
   }
 }