fixed support for wrap-around levels in EM engine for old tapes
[rocksndiamonds.git] / src / game_em / convert.c
index 9b888ffce11733dff5f6825af16a24491971ee77..bae0130c3920adcd4ed56a4e3e0ea4a0474855d5 100644 (file)
-/* 2000-08-20T09:41:18Z
+/* 2007-04-04 08:33:37
  *
- * identify all emerald mine caves and turn them into v6 format.
- * fixes illegal tiles, acid, wheel, limits times, cleans flags.
- *
- * these tables weed out bad tiles for older caves (eg. wheel on -> wheel off)
- * and clean up v6 caves (acid, number limits) which should(!) be
- * inconsequential, but no doubt it will break some caves.
+ * convert intermediate cave format to internal cave structure for
+ * use in logic(). initializes entire internal structure.
  */
 
-#include "global.h"
-#include "tile.h"
-#include "level.h"
-
-
-static unsigned char remap_v6[256] =
-{
-  /* filter crap for v6 */
-
-  0,0,2,2,         4,4,118,118,     8,9,10,11,       12,13,14,15,
-  16,16,18,18,     20,21,22,23,     24,25,26,27,     28,28,118,28,
-  0,16,2,18,       36,37,37,37,     40,41,42,43,     44,45,128,128,
-  128,148,148,     148,45,45,45,    148,0,57,58,     59,60,61,62,63,
-
-  64,65,66,67,     68,69,69,69,     69,73,74,75,     118,75,75,75,
-  75,75,75,75,     75,153,153,153,  153,153,153,153, 153,153,153,153,
-  153,153,153,99,  100,68,68,68,    68,68,68,68,     68,118,118,118,
-  118,118,114,115, 131,118,118,119, 120,121,122,118, 118,118,118,118,
-
-  128,129,130,131, 132,133,134,135, 136,137,138,139, 140,141,142,143,
-  144,145,146,147, 148,149,150,151, 152,153,154,155, 156,157,158,159,
-  160,161,162,163, 164,165,165,118, 168,169,170,171, 172,173,174,175,
-  176,177,178,179, 180,181,182,183, 184,185,186,187, 188,189,68,191,
-
-  192,193,194,195, 196,197,198,199, 200,201,202,203, 204,205,206,207,
-  208,209,210,211, 212,213,214,215, 216,217,218,219, 220,221,222,223,
-  224,225,226,227, 228,229,230,231, 232,233,234,235, 236,237,238,239,
-  240,241,242,243, 244,245,153,153, 153,153,153,153, 153,153,153,153
-};
+#include "main_em.h"
 
-static unsigned char remap_v5[256] =
-{
-  /* filter crap for v5 */
-
-  0,0,2,2,         4,4,118,118,     8,9,10,11,       12,13,14,15,
-  16,16,18,18,     20,21,22,23,     24,25,26,27,     28,28,118,28,
-  0,16,2,18,       36,37,37,37,     147,41,42,43,    44,45,128,128,
-  128,148,148,148, 45,45,45,148,    0,57,58,59,      60,61,62,63,
-
-  64,65,66,67,     68,153,153,153,  153,153,153,153, 153,153,153,153,
-  153,153,153,153, 153,153,153,153, 153,153,153,153, 153,153,153,153,
-  153,153,153,153, 153,68,68,68,68, 68,68,68,68,118, 118,118,
-  118,118,114,115, 131,118,118,119, 120,121,122,118, 118,118,118,118,
-
-  128,129,130,131, 132,133,134,135, 136,137,138,139, 140,141,142,143,
-  144,145,146,147, 148,149,150,151, 152,153,154,155, 156,157,158,159,
-  160,153,153,153, 153,153,153,118, 168,169,170,171, 172,173,174,175,
-  176,177,178,179, 180,181,182,183, 184,185,186,187, 188,189,68,153,
-
-  153,153,153,153, 153,153,153,153, 200,201,202,203, 204,205,206,207,
-  208,209,210,211, 212,213,214,215, 216,217,218,219, 220,221,222,223,
-  224,225,226,227, 228,229,230,231, 232,233,234,235, 236,237,238,239,
-  240,241,153,153, 153,153,153,153, 153,153,153,153, 153,153,153,153
-};
-
-static unsigned char remap_v4[256] =
-{
-  /* filter crap for v4 */
-
-  0,0,2,2,         4,4,118,118,     8,9,10,11,       12,13,14,15,
-  16,16,18,18,     20,21,22,23,     24,25,26,27,     28,28,118,28,
-  0,16,2,18,       36,37,37,37,     147,41,42,43,    44,45,128,128,
-  128,148,148,148, 45,45,45,148,    0,153,153,59,    60,61,62,63,
-
-  64,65,66,153,    153,153,153,153, 153,153,153,153, 153,153,153,153,
-  153,153,153,153, 153,153,153,153, 153,153,153,153, 153,153,153,153,
-  153,153,153,153, 153,153,153,153, 153,153,153,153, 153,153,153,153,
-  153,118,114,115, 131,118,118,119, 120,121,122,118, 118,118,118,118,
-
-  128,129,130,131, 132,133,134,135, 136,137,138,139, 140,141,142,143,
-  144,145,146,147, 148,149,150,151, 152,68,154,155,  156,157,158,160,
-  160,160,160,160, 160,160,160,160, 160,160,160,160, 160,160,160,175,
-  153,153,153,153, 153,153,153,153, 153,153,153,153, 153,153,68,153,
-
-  153,153,153,153, 153,153,153,153, 200,201,202,203, 204,205,206,207,
-  208,209,210,211, 212,213,214,215, 216,217,218,219, 220,221,222,223,
-  224,225,226,227, 228,229,230,231, 232,233,234,235, 236,237,238,239,
-  240,241,153,153, 153,153,153,153, 153,153,153,153, 153,153,153,153
-};
 
-static unsigned char remap_v4eater[28] =
+static const short map[CAVE_TILE_MAX] =
 {
-  /* filter crap for v4 */
-
-  128,18,2,0,4,8,16,20,28,37,
-  41,45,130,129,131,132,133,134,135,136,
-  146,147,175,65,66,64,2,18
+  [Cblank]             = Xblank,
+  [Cgrass]             = Xgrass,
+  [Cdirt]              = Xdirt,
+  [Cplant]             = Xplant,
+  [Cwall_1]            = Xwall_1,
+  [Cwall_2]            = Xwall_2,
+  [Cwall_3]            = Xwall_3,
+  [Cwall_4]            = Xwall_4,
+  [Croundwall_1]       = Xroundwall_1,
+  [Croundwall_2]       = Xroundwall_2,
+  [Croundwall_3]       = Xroundwall_3,
+  [Croundwall_4]       = Xroundwall_4,
+  [Csteel_1]           = Xsteel_1,
+  [Csteel_2]           = Xsteel_2,
+  [Csteel_3]           = Xsteel_3,
+  [Csteel_4]           = Xsteel_4,
+  [Candroid]           = Xandroid,
+  [Ceater_n]           = Xeater_n,
+  [Ceater_e]           = Xeater_e,
+  [Ceater_s]           = Xeater_s,
+  [Ceater_w]           = Xeater_w,
+  [Calien]             = Xalien,
+  [Cbug_1_n]           = Xbug_1_n,
+  [Cbug_1_e]           = Xbug_1_e,
+  [Cbug_1_s]           = Xbug_1_s,
+  [Cbug_1_w]           = Xbug_1_w,
+  [Cbug_2_n]           = Xbug_2_n,
+  [Cbug_2_e]           = Xbug_2_e,
+  [Cbug_2_s]           = Xbug_2_s,
+  [Cbug_2_w]           = Xbug_2_w,
+  [Ctank_1_n]          = Xtank_1_n,
+  [Ctank_1_e]          = Xtank_1_e,
+  [Ctank_1_s]          = Xtank_1_s,
+  [Ctank_1_w]          = Xtank_1_w,
+  [Ctank_2_n]          = Xtank_2_n,
+  [Ctank_2_e]          = Xtank_2_e,
+  [Ctank_2_s]          = Xtank_2_s,
+  [Ctank_2_w]          = Xtank_2_w,
+  [Cemerald]           = Xemerald,
+  [Cdiamond]           = Xdiamond,
+  [Cstone]             = Xstone,
+  [Cbomb]              = Xbomb,
+  [Cnut]               = Xnut,
+  [Cspring]            = Xspring,
+  [Cpush_emerald_e]    = Xpush_emerald_e,
+  [Cpush_emerald_w]    = Xpush_emerald_w,
+  [Cpush_diamond_e]    = Xpush_diamond_e,
+  [Cpush_diamond_w]    = Xpush_diamond_w,
+  [Cpush_stone_e]      = Xpush_stone_e,
+  [Cpush_stone_w]      = Xpush_stone_w,
+  [Cpush_bomb_e]       = Xpush_bomb_e,
+  [Cpush_bomb_w]       = Xpush_bomb_w,
+  [Cpush_nut_e]                = Xpush_nut_e,
+  [Cpush_nut_w]                = Xpush_nut_w,
+  [Cpush_spring_e]     = Xpush_spring_e,
+  [Cpush_spring_w]     = Xpush_spring_w,
+  [Cdynamite]          = Xdynamite,
+  [Cdynamite_1]                = Xdynamite_1,
+  [Cdynamite_2]                = Xdynamite_2,
+  [Cdynamite_3]                = Xdynamite_3,
+  [Cdynamite_4]                = Xdynamite_4,
+  [Ckey_1]             = Xkey_1,
+  [Ckey_2]             = Xkey_2,
+  [Ckey_3]             = Xkey_3,
+  [Ckey_4]             = Xkey_4,
+  [Ckey_5]             = Xkey_5,
+  [Ckey_6]             = Xkey_6,
+  [Ckey_7]             = Xkey_7,
+  [Ckey_8]             = Xkey_8,
+  [Cdoor_1]            = Xdoor_1,
+  [Cdoor_2]            = Xdoor_2,
+  [Cdoor_3]            = Xdoor_3,
+  [Cdoor_4]            = Xdoor_4,
+  [Cdoor_5]            = Xdoor_5,
+  [Cdoor_6]            = Xdoor_6,
+  [Cdoor_7]            = Xdoor_7,
+  [Cdoor_8]            = Xdoor_8,
+  [Cfake_door_1]       = Xfake_door_1,
+  [Cfake_door_2]       = Xfake_door_2,
+  [Cfake_door_3]       = Xfake_door_3,
+  [Cfake_door_4]       = Xfake_door_4,
+  [Cfake_door_5]       = Xfake_door_5,
+  [Cfake_door_6]       = Xfake_door_6,
+  [Cfake_door_7]       = Xfake_door_7,
+  [Cfake_door_8]       = Xfake_door_8,
+  [Cballoon]           = Xballoon,
+  [Cball_1]            = Xball_1,
+  [Cball_2]            = Xball_2,
+  [Camoeba_1]          = Xamoeba_1,
+  [Camoeba_2]          = Xamoeba_2,
+  [Camoeba_3]          = Xamoeba_3,
+  [Camoeba_4]          = Xamoeba_4,
+  [Camoeba_5]          = Xamoeba_5,
+  [Camoeba_6]          = Xamoeba_6,
+  [Camoeba_7]          = Xamoeba_7,
+  [Camoeba_8]          = Xamoeba_8,
+  [Cdrip]              = Xdrip,
+  [Cwonderwall]                = Xwonderwall,
+  [Cwheel]             = Xwheel,
+  [Cswitch]            = Xswitch,
+  [Cbumper]            = Xbumper,
+  [Cacid_nw]           = Xacid_nw,
+  [Cacid_ne]           = Xacid_ne,
+  [Cacid_sw]           = Xacid_sw,
+  [Cacid_s]            = Xacid_s,
+  [Cacid_se]           = Xacid_se,
+  [Cacid_1]            = Xacid_1,
+  [Cacid_2]            = Xacid_2,
+  [Cacid_3]            = Xacid_3,
+  [Cacid_4]            = Xacid_4,
+  [Cacid_5]            = Xacid_5,
+  [Cacid_6]            = Xacid_6,
+  [Cacid_7]            = Xacid_7,
+  [Cacid_8]            = Xacid_8,
+  [Cfake_acid_1]       = Xfake_acid_1,
+  [Cfake_acid_2]       = Xfake_acid_2,
+  [Cfake_acid_3]       = Xfake_acid_3,
+  [Cfake_acid_4]       = Xfake_acid_4,
+  [Cfake_acid_5]       = Xfake_acid_5,
+  [Cfake_acid_6]       = Xfake_acid_6,
+  [Cfake_acid_7]       = Xfake_acid_7,
+  [Cfake_acid_8]       = Xfake_acid_8,
+  [Cfake_blank]                = Xfake_blank,
+  [Cfake_grass]                = Xfake_grass,
+  [Cfake_amoeba]       = Xfake_amoeba,
+  [Clenses]            = Xlenses,
+  [Cmagnify]           = Xmagnify,
+  [Csand]              = Xsand,
+  [Csand_stone]                = Xsand_stone,
+  [Cslide_ns]          = Xslide_ns,
+  [Cslide_ew]          = Xslide_ew,
+  [Cwind_n]            = Xwind_n,
+  [Cwind_e]            = Xwind_e,
+  [Cwind_s]            = Xwind_s,
+  [Cwind_w]            = Xwind_w,
+  [Cwind_any]          = Xwind_any,
+  [Cwind_stop]         = Xwind_stop,
+  [Cexit]              = Xexit,
+  [Cexit_1]            = Xexit_1,
+  [Cexit_2]            = Xexit_2,
+  [Cexit_3]            = Xexit_3,
+  [Cpause]             = Xpause,
+  [Cdecor_1]           = Xdecor_1,
+  [Cdecor_2]           = Xdecor_2,
+  [Cdecor_3]           = Xdecor_3,
+  [Cdecor_4]           = Xdecor_4,
+  [Cdecor_5]           = Xdecor_5,
+  [Cdecor_6]           = Xdecor_6,
+  [Cdecor_7]           = Xdecor_7,
+  [Cdecor_8]           = Xdecor_8,
+  [Cdecor_9]           = Xdecor_9,
+  [Cdecor_10]          = Xdecor_10,
+  [Cdecor_11]          = Xdecor_11,
+  [Cdecor_12]          = Xdecor_12,
+  [Calpha_0]           = Xalpha_0,
+  [Calpha_1]           = Xalpha_1,
+  [Calpha_2]           = Xalpha_2,
+  [Calpha_3]           = Xalpha_3,
+  [Calpha_4]           = Xalpha_4,
+  [Calpha_5]           = Xalpha_5,
+  [Calpha_6]           = Xalpha_6,
+  [Calpha_7]           = Xalpha_7,
+  [Calpha_8]           = Xalpha_8,
+  [Calpha_9]           = Xalpha_9,
+  [Calpha_excla]       = Xalpha_excla,
+  [Calpha_apost]       = Xalpha_apost,
+  [Calpha_comma]       = Xalpha_comma,
+  [Calpha_minus]       = Xalpha_minus,
+  [Calpha_perio]       = Xalpha_perio,
+  [Calpha_colon]       = Xalpha_colon,
+  [Calpha_quest]       = Xalpha_quest,
+  [Calpha_a]           = Xalpha_a,
+  [Calpha_b]           = Xalpha_b,
+  [Calpha_c]           = Xalpha_c,
+  [Calpha_d]           = Xalpha_d,
+  [Calpha_e]           = Xalpha_e,
+  [Calpha_f]           = Xalpha_f,
+  [Calpha_g]           = Xalpha_g,
+  [Calpha_h]           = Xalpha_h,
+  [Calpha_i]           = Xalpha_i,
+  [Calpha_j]           = Xalpha_j,
+  [Calpha_k]           = Xalpha_k,
+  [Calpha_l]           = Xalpha_l,
+  [Calpha_m]           = Xalpha_m,
+  [Calpha_n]           = Xalpha_n,
+  [Calpha_o]           = Xalpha_o,
+  [Calpha_p]           = Xalpha_p,
+  [Calpha_q]           = Xalpha_q,
+  [Calpha_r]           = Xalpha_r,
+  [Calpha_s]           = Xalpha_s,
+  [Calpha_t]           = Xalpha_t,
+  [Calpha_u]           = Xalpha_u,
+  [Calpha_v]           = Xalpha_v,
+  [Calpha_w]           = Xalpha_w,
+  [Calpha_x]           = Xalpha_x,
+  [Calpha_y]           = Xalpha_y,
+  [Calpha_z]           = Xalpha_z,
+  [Calpha_arrow_e]     = Xalpha_arrow_e,
+  [Calpha_arrow_w]     = Xalpha_arrow_w,
+  [Calpha_copyr]       = Xalpha_copyr
 };
 
-int cleanup_em_level(unsigned char *src, int length)
+int map_em_element_C_to_X(int element_em_cave)
 {
-  int file_version = 0;
-  int i;
-
-  if (length >= 2172 &&
-      src[2106] == 255 &&
-      src[2107] == 54 &&
-      src[2108] == 48 &&
-      src[2109] == 48)
-  {
-    /* ---------- this cave has V6 file format ---------- */
-    file_version = FILE_VERSION_EM_V6;
-
-    for (i = 0; i < 2048; i++)
-      src[i] = remap_v6[src[i]];
-    for (i = 2048; i < 2084; i++)
-      src[i] = remap_v6[src[i]];
-    for (i = 2112; i < 2148; i++)
-      src[i] = remap_v6[src[i]];
-  }
-  else if (length >= 2110 &&
-          src[2106] == 255 &&
-          src[2107] == 53 &&
-          src[2108] == 48 &&
-          src[2109] == 48)
-  {
-    /* ---------- this cave has V5 file format ---------- */
-    file_version = FILE_VERSION_EM_V5;
-
-    for (i = 0; i < 2048; i++)
-      src[i] = remap_v5[src[i]];
-    for (i = 2048; i < 2084; i++)
-      src[i] = remap_v5[src[i]];
-    for (i = 2112; i < 2148; i++)
-      src[i] = src[i - 64];
-  }
-#if 0
-  else if (length >= 2106)     /* !!! TEST ONLY: SHOW BROKEN LEVELS !!! */
-#else
-  else if (length >= 2106 &&
-          src[1983] == 116)
-#endif
-  {
-    /* ---------- this cave has V4 file format ---------- */
-    file_version = FILE_VERSION_EM_V4;
-
-    for (i = 0; i < 2048; i++)
-      src[i] = remap_v4[src[i]];
-    for (i = 2048; i < 2084; i++)
-      src[i] = remap_v4eater[src[i] >= 28 ? 0 : src[i]];
-    for (i = 2112; i < 2148; i++) src[i] = src[i - 64];
-  }
-  else if (length >= 2106 &&
-          src[0] == 241 &&
-          src[1983] == 27)
-  {
-    unsigned char j = 94;
-
-    /* ---------- this cave has V3 file format ---------- */
-    file_version = FILE_VERSION_EM_V3;
-
-    for (i = 0; i < 2106; i++)
-      src[i] = (src[i] ^ (j += 7)) - 0x11;
-    src[1] = 131;
-    for (i = 0; i < 2048; i++)
-      src[i] = remap_v4[src[i]];
-    for (i = 2048; i < 2084; i++)
-      src[i] = remap_v4eater[src[i] >= 28 ? 0 : src[i]];
-    for (i = 2112; i < 2148; i++)
-      src[i] = src[i - 64];
-  }
-#if 1
-  else if (length >= 2106 &&
-          src[0] == 245 &&
-          src[1983] == 27)
-  {
-    unsigned char j = 94;
-
-    /* ---------- this cave has V3 file format ---------- */
-    file_version = FILE_VERSION_EM_V3;
-
-    for (i = 0; i < 2106; i++)
-      src[i] = (src[i] ^ (j += 7)) - 0x11;
-    src[1] = 131;
-    for (i = 0; i < 2048; i++)
-      src[i] = remap_v4[src[i]];
-    for (i = 2048; i < 2084; i++)
-      src[i] = remap_v4eater[src[i] >= 28 ? 0 : src[i]];
-    for (i = 2112; i < 2148; i++)
-      src[i] = src[i - 64];
-  }
-#endif
-  else
+  if (element_em_cave < 0 || element_em_cave >= CAVE_TILE_MAX)
   {
-    /* ---------- this cave has unknown file format ---------- */
-
-#if 1
-    printf("::: %d, %d\n", src[0], src[1983]);
-#endif
-
-    return 0;
-  }
-
-  if (file_version < FILE_VERSION_EM_V6)
-  {
-    /* id */
-    src[2106] = 255;
-    src[2107] = 54;
-    src[2108] = 48;
-    src[2109] = 48;
-
-    /* time */
-    i = src[2094] * 10;
-    src[2110] = i >> 8;
-    src[2111] = i;
-
-    for (i = 2148; i < 2172; i++)
-      src[i] = 0;
-
-    /* ball data */
-    src[2159] = 128;
-  }
+    Error(ERR_WARN, "invalid EM cave element %d", element_em_cave);
 
-  /* ---------- at this stage, the cave data always has V6 format ---------- */
-
-  /* fix wheel */
-  for (i = 0; i < 2048; i++)
-    if (src[i] == 40)
-      break;
-  for (i++; i < 2048; i++)
-    if (src[i] == 40)
-      src[i] = 147;
-
-#if 0
-  /* fix acid */
-  for (i = 64; i < 2048; i++)
-    if (src[i] == 63)          /* replace element above 'Xacid_s' ... */
-      src[i - 64] = 101;       /* ... with 'Xacid_1' */
-
-#else
-
-  /* fix acid */
-  for (i = 64; i < 2048; i++)
-  {
-    if (src[i] == 63)          /* 'Xacid_s' (acid pool, bottom middle) */
-    {
-      if (file_version == FILE_VERSION_EM_V4 &&
-         i < 2048 - 64 && src[i + 64] == 63)
-       src[i - 64] = 255;      /* replace element above with 'Xfake_acid_1' */
-      else
-       src[i - 64] = 101;      /* replace element above with 'Xacid_1' */
-    }
-  }
-#endif
-
-  /* fix acid in eater 1 */
-  for (i = 2051; i < 2057; i++)
-    if (src[i] == 63)
-      src[i - 3] = 101;
-
-  /* fix acid in eater 2 */
-  for (i = 2060; i < 2066; i++)
-    if (src[i] == 63)
-      src[i - 3] = 101;
-
-  /* fix acid in eater 3 */
-  for (i = 2069; i < 2075; i++)
-    if (src[i] == 63)
-      src[i - 3] = 101;
-
-  /* fix acid in eater 4 */
-  for (i = 2078; i < 2084; i++)
-    if (src[i] == 63)
-      src[i - 3] = 101;
-
-  /* fix acid in eater 5 */
-  for (i = 2115; i < 2121; i++)
-    if (src[i] == 63)
-      src[i - 3] = 101;
-
-  /* fix acid in eater 6 */
-  for (i = 2124; i < 2130; i++)
-    if (src[i] == 63)
-      src[i - 3] = 101;
-
-  /* fix acid in eater 7 */
-  for (i = 2133; i < 2139; i++)
-    if (src[i] == 63)
-      src[i - 3] = 101;
-
-  /* fix acid in eater 8 */
-  for (i = 2142; i < 2148; i++)
-    if (src[i] == 63)
-      src[i - 3] = 101;
-
-  /* old style time */
-  src[2094] = 0;
-
-  /* player 1 pos */
-  src[2096] &= 7;
-  src[src[2096] << 8 | src[2097]] = 128;
-
-  /* player 2 pos */
-  src[2098] &= 7;
-  src[src[2098] << 8 | src[2099]] = 128;
-
-  /* amoeba speed */
-  if ((src[2100] << 8 | src[2101]) > 9999)
-  {
-    src[2100] = 39;
-    src[2101] = 15;
+    return Xblank;
   }
 
-  /* time wonderwall */
-  if ((src[2102] << 8 | src[2103]) > 9999)
-  {
-    src[2102] = 39;
-    src[2103] = 15;
-  }
-
-  /* time */
-  if ((src[2110] << 8 | src[2111]) > 9999)
-  {
-    src[2110] = 39;
-    src[2111] = 15;
-  }
+  return map[element_em_cave];
+}
 
-  /* wind direction */
-  i = src[2149];
-  i &= 15;
-  i &= -i;
-  src[2149] = i;
+int map_em_element_X_to_C(int element_em_game)
+{
+  static unsigned short map_reverse[GAME_TILE_MAX];
+  static boolean map_reverse_initialized = FALSE;
 
-  /* time lenses */
-  if ((src[2154] << 8 | src[2155]) > 9999)
+  if (!map_reverse_initialized)
   {
-    src[2154] = 39;
-    src[2155] = 15;
-  }
+    int i;
 
-  /* time magnify */
-  if ((src[2156] << 8 | src[2157]) > 9999)
-  {
-    src[2156] = 39;
-    src[2157] = 15;
-  }
+    // return "Cblank" for all undefined elements in mapping array
+    for (i = 0; i < GAME_TILE_MAX; i++)
+      map_reverse[i] = Cblank;
 
-  /* ball object */
-  src[2158] = 0;
-  src[2159] = remap_v6[src[2159]];
+    for (i = 0; i < CAVE_TILE_MAX; i++)
+      map_reverse[map[i]] = i;
 
-  /* ball pause */
-  if ((src[2160] << 8 | src[2161]) > 9999)
-  {
-    src[2160] = 39;
-    src[2161] = 15;
+    map_reverse_initialized = TRUE;
   }
 
-  /* ball data */
-  src[2162] &= 129;
-  if (src[2162] & 1)
-    src[2163] = 0;
-
-  /* android move pause */
-  if ((src[2164] << 8 | src[2165]) > 9999)
+  if (element_em_game < 0 || element_em_game >= GAME_TILE_MAX)
   {
-    src[2164] = 39;
-    src[2165] = 15;
-  }
+    Error(ERR_WARN, "invalid EM game element %d", element_em_game);
 
-  /* android clone pause */
-  if ((src[2166] << 8 | src[2167]) > 9999)
-  {
-    src[2166] = 39;
-    src[2167] = 15;
+    return Cblank;
   }
 
-  /* android data */
-  src[2168] &= 31;
+  int element_em_cave = map_reverse[element_em_game];
 
-  /* size of v6 cave */
-  length = 2172;
+  if (element_em_cave == Cblank && element_em_game != Xblank)
+    Error(ERR_WARN, "unknown EM game element %d", element_em_game);
 
-#if 1
-  if (options.debug)
-    printf("::: EM level file version: %d\n", file_version);
-#endif
-
-  return file_version;
+  return element_em_cave;
 }
 
-/* 2000-07-30T00:26:00Z
- *
- * Read emerald mine caves version 6
- *
- * v4 and v5 emerald mine caves are converted to v6 (which completely supports
- * older versions)
- * 
- * converting to the internal format loses /significant/ information which can
- * break lots of caves.
- * 
- * major incompatibilities:
- * - borderless caves behave completely differently, the player no longer
- *   "warps" to the other side.
- * - a compile time option for spring can make it behave differently when it
- *   rolls.
- * - a compile time option for rolling objects (stone, nut, spring, bomb) only
- *   in eater.
- * - acid is always deadly even with no base beneath it (this breaks cave 0 in
- *   downunder mine 16)
- *
- * so far all below have not broken any caves:
- *
- * - active wheel inside an eater will not function, eater explosions will not
- *   change settings.
- * - initial collect objects (emerald, diamond, dynamite) don't exist.
- * - initial rolling objects will be moved manually and made into sitting
- *   objects.
- * - drips always appear from dots.
- * - more than one thing can fall into acid at the same time.
- * - acid explodes when the player walks into it, rather than splashing.
- * - simultaneous explosions may be in a slightly different order.
- * - quicksand states have been reduced.
- * - acid base is effectively an indestructable wall now which can affect eater
- *   explosions.
- * - android can clone forever with a clone pause of 0 (emeralds, diamonds,
- *   nuts, stones, bombs, springs).
- *
- * 2001-03-12T02:46:55Z
- * - rolling stuff is now allowed in the cave, i didn't like making this
- *   decision.
- * - if BAD_ROLL is not defined, initial rolling objects are moved by hand.
- * - initial collect objects break some cave in elvis mine 5.
- * - different timing for wonderwall break some cave in exception mine 2.
- * - i think i'm pretty locked into always using the bad roll. *sigh*
- * - rolling spring is now turned into regular spring. it appears the emc
- *   editor only uses the force code for initially moving spring. i will
- *   follow this in my editor.
- */
-
-static unsigned short remap_emerald[256] =
+void prepare_em_level(void)
 {
-  Xstone,              Xstone,         Xdiamond,       Xdiamond,
-  Xalien,              Xalien,         Xblank,         Xblank,
-  Xtank_n,             Xtank_e,        Xtank_s,        Xtank_w,
-  Xtank_gon,           Xtank_goe,      Xtank_gos,      Xtank_gow,
-
-  Xbomb,               Xbomb,          Xemerald,       Xemerald,
-  Xbug_n,              Xbug_e,         Xbug_s,         Xbug_w,
-  Xbug_gon,            Xbug_goe,       Xbug_gos,       Xbug_gow,
-  Xdrip_eat,           Xdrip_eat,      Xdrip_eat,      Xdrip_eat,
-
-  Xstone,              Xbomb,          Xdiamond,       Xemerald,
-  Xwonderwall,         Xnut,           Xnut,           Xnut,
-  Xwheel,              Xeater_n,       Xeater_s,       Xeater_w,
-  Xeater_e,            Xsand_stone,    Xblank,         Xblank,
-
-  Xblank,              Xsand,          Xsand,          Xsand,
-  Xsand_stone,         Xsand_stone,    Xsand_stone,    Xsand,
-  Xstone,              Xgrow_ew,       Xgrow_ns,       Xdynamite_1,
-  Xdynamite_2,         Xdynamite_3,    Xdynamite_4,    Xacid_s,
-
-  Xexit_1,             Xexit_2,        Xexit_3,        Xballoon,
-  Xplant,              Xspring,        Xspring,        Xspring,
-  Xspring,             Xball_1,        Xball_2,        Xandroid,
-  Xblank,              Xandroid,       Xandroid,       Xandroid,
-
-  Xandroid,            Xandroid,       Xandroid,       Xandroid,
-  Xandroid,            Xblank,         Xblank,         Xblank,
-  Xblank,              Xblank,         Xblank,         Xblank,
-  Xblank,              Xblank,         Xblank,         Xblank,
-
-#ifdef BAD_ROLL
-
-  Xblank,              Xblank,         Xblank,         Xspring_force_w,
-  Xspring_force_e,     Xacid_1,        Xacid_2,        Xacid_3,
-  Xacid_4,             Xacid_5,        Xacid_6,        Xacid_7,
-  Xacid_8,             Xblank,         Xblank,         Xblank,
-
-  Xblank,              Xblank,         Xnut_force_w,   Xnut_force_e,
-  Xsteel_1,            Xblank,         Xblank,         Xbomb_force_w,
-  Xbomb_force_e,       Xstone_force_w, Xstone_force_e, Xblank,
-  Xblank,              Xblank,         Xblank,         Xblank,
-
-#else
-
-  Xblank,              Xblank,         Xblank,         Xspring,
-  Xspring,             Xacid_1,        Xacid_2,        Xacid_3,
-  Xacid_4,             Xacid_5,        Xacid_6,        Xacid_7,
-  Xacid_8,             Xblank,         Xblank,         Xblank,
-
-  Xblank,              Xblank,         Xnut,           Xnut,
-  Xsteel_1,            Xblank,         Xblank,         Xbomb,
-  Xbomb,               Xstone,         Xstone,         Xblank,
-  Xblank,              Xblank,         Xblank,         Xblank,
-
-#endif
-
-  Xblank,              Xround_wall_1,  Xgrass,         Xsteel_1,
-  Xwall_1,             Xkey_1,         Xkey_2,         Xkey_3,
-  Xkey_4,              Xdoor_1,        Xdoor_2,        Xdoor_3,
-  Xdoor_4,             Xdripper,       Xfake_door_1,   Xfake_door_2,
-
-  Xfake_door_3,                Xfake_door_4,   Xwonderwall,    Xwheel,
-  Xsand,               Xacid_nw,       Xacid_ne,       Xacid_sw,
-  Xacid_se,            Xfake_blank,    Xamoeba_1,      Xamoeba_2,
-  Xamoeba_3,           Xamoeba_4,      Xexit,          Xalpha_arrow_w,
-
-  Xfake_grass,         Xlenses,        Xmagnify,       Xfake_blank,
-  Xfake_grass,         Xswitch,        Xswitch,        Xblank,
-  Xdecor_8,            Xdecor_9,       Xdecor_10,      Xdecor_5,
-  Xalpha_comma,                Xalpha_quote,   Xalpha_minus,   Xdynamite,
-
-  Xsteel_3,            Xdecor_6,       Xdecor_7,       Xsteel_2,
-  Xround_wall_2,       Xdecor_2,       Xdecor_4,       Xdecor_3,
-  Xwind_nesw,          Xwind_e,        Xwind_s,        Xwind_w,
-  Xwind_n,             Xdirt,          Xplant,         Xkey_5,
-
-  Xkey_6,              Xkey_7,         Xkey_8,         Xdoor_5,
-  Xdoor_6,             Xdoor_7,        Xdoor_8,        Xbumper,
-  Xalpha_a,            Xalpha_b,       Xalpha_c,       Xalpha_d,
-  Xalpha_e,            Xalpha_f,       Xalpha_g,       Xalpha_h,
-
-  Xalpha_i,            Xalpha_j,       Xalpha_k,       Xalpha_l,
-  Xalpha_m,            Xalpha_n,       Xalpha_o,       Xalpha_p,
-  Xalpha_q,            Xalpha_r,       Xalpha_s,       Xalpha_t,
-  Xalpha_u,            Xalpha_v,       Xalpha_w,       Xalpha_x,
-
-  Xalpha_y,            Xalpha_z,       Xalpha_0,       Xalpha_1,
-  Xalpha_2,            Xalpha_3,       Xalpha_4,       Xalpha_5,
-  Xalpha_6,            Xalpha_7,       Xalpha_8,       Xalpha_9,
-  Xalpha_perio,                Xalpha_excla,   Xalpha_colon,   Xalpha_quest,
-
-  Xalpha_arrow_e,      Xdecor_1,       Xfake_door_5,   Xfake_door_6,
-  Xfake_door_7,                Xfake_door_8,   Xblank,         Xblank,
-  Xblank,              Xblank,         Xblank,         Xblank,
-#if 0
-  Xblank,              Xblank,         Xblank,         Xblank,
-#else
-  /* special elements added to solve compatibility problems */
-  Xblank,              Xblank,         Xblank,         Xfake_acid_1
-#endif
-};
+  int i, j, x, y;
+  int players_left;
+  boolean team_mode;
 
-void convert_em_level(unsigned char *src, int file_version)
-{
-  static int eater_offset[8] =
-  {
-    0x800, 0x809, 0x812, 0x81B, 0x840, 0x849, 0x852, 0x85B
-  };
-  int i, x, y, temp;
-
-#if 1
-  lev.time_seconds = src[0x83E] << 8 | src[0x83F];
-  if (lev.time_seconds > 9999)
-    lev.time_seconds = 9999;
-#else
-  temp = ((src[0x83E] << 8 | src[0x83F]) * 25 + 3) / 4;
-  if (temp == 0 || temp > 9999)
-    temp = 9999;
-  lev.time_initial = temp;
-#endif
-
-  lev.required_initial = src[0x82F];
-
-  for (i = 0; i < 2; i++)
-  {
-    temp = src[0x830 + i * 2] << 8 | src[0x831 + i * 2];
-    ply[i].x_initial = (temp & 63) + 1;
-    ply[i].y_initial = (temp >> 6 & 31) + 1;
-  }
+  /* reset all runtime variables to their initial values */
 
-  temp = (src[0x834] << 8 | src[0x835]) * 28;
-  if (temp > 9999)
-    temp = 9999;
-  lev.amoeba_time = temp;
-
-  lev.android_move_time = src[0x874] << 8 | src[0x875];
-  lev.android_clone_time = src[0x876] << 8 | src[0x877];
-
-  lev.ball_random = src[0x872] & 1 ? 1 : 0;
-  lev.ball_state_initial = src[0x872] & 128 ? 1 : 0;
-  lev.ball_time = src[0x870] << 8 | src[0x871];
-
-  lev.emerald_score = src[0x824];
-  lev.diamond_score = src[0x825];
-  lev.alien_score = src[0x826];
-  lev.tank_score = src[0x827];
-  lev.bug_score = src[0x828];
-  lev.eater_score = src[0x829];
-  lev.nut_score = src[0x82A];
-  lev.dynamite_score = src[0x82B];
-  lev.key_score = src[0x82C];
-  lev.exit_score = src[0x82D] * 8 / 5;
-  lev.lenses_score = src[0x867];
-  lev.magnify_score = src[0x868];
-  lev.slurp_score = src[0x869];
-
-  lev.lenses_time = src[0x86A] << 8 | src[0x86B];
-  lev.magnify_time = src[0x86C] << 8 | src[0x86D];
-  lev.wheel_time = src[0x838] << 8 | src[0x839];
-
-  lev.wind_cnt_initial = src[0x865] & 15 ? lev.wind_time : 0;
-  temp = src[0x865];
-  lev.wind_direction_initial = (temp & 8 ? 0 :
-                               temp & 1 ? 1 :
-                               temp & 2 ? 2 :
-                               temp & 4 ? 3 : 0);
-
-  lev.wonderwall_time_initial = src[0x836] << 8 | src[0x837];
+  game_init_cave_buffers();
 
-  for (i = 0; i < 8; i++)
-    for (x = 0; x < 9; x++)
-      lev.eater_array[i][x] = remap_emerald[src[eater_offset[i] + x]];
+  lev.width  = cav.width;
+  lev.height = cav.height;
 
-  temp = remap_emerald[src[0x86F]];
-  for (y = 0; y < 8; y++)
+  lev.left = CAVE_BUFFER_XOFFSET;
+  lev.top  = CAVE_BUFFER_YOFFSET;
+  lev.right = lev.left + lev.width;
+  lev.bottom = lev.top + lev.height;
+
+  if (cav.infinite)
   {
-    if (src[0x872] & 1)
-    {
-      for (x = 0; x < 8; x++)
-       lev.ball_array[y][x] = temp;
-    }
-    else
+    /* add linked cave buffer columns for wrap-around movement */
+    for (x = 0; x < lev.left; x++)
     {
-      lev.ball_array[y][1] = (src[0x873] & 1)  ? temp : Xblank; /* north */
-      lev.ball_array[y][6] = (src[0x873] & 2)  ? temp : Xblank; /* south */
-      lev.ball_array[y][3] = (src[0x873] & 4)  ? temp : Xblank; /* west */
-      lev.ball_array[y][4] = (src[0x873] & 8)  ? temp : Xblank; /* east */
-      lev.ball_array[y][7] = (src[0x873] & 16) ? temp : Xblank; /* southeast */
-      lev.ball_array[y][5] = (src[0x873] & 32) ? temp : Xblank; /* southwest */
-      lev.ball_array[y][2] = (src[0x873] & 64) ? temp : Xblank; /* northeast */
-      lev.ball_array[y][0] = (src[0x873] & 128)? temp : Xblank; /* northwest */
+      lev.cavecol[x] = lev.cavecol[lev.width + x];
+      lev.nextcol[x] = lev.nextcol[lev.width + x];
+      lev.drawcol[x] = lev.drawcol[lev.width + x];
+      lev.boomcol[x] = lev.boomcol[lev.width + x];
+
+      lev.cavecol[lev.right + x] = lev.cavecol[lev.left + x];
+      lev.nextcol[lev.right + x] = lev.nextcol[lev.left + x];
+      lev.drawcol[lev.right + x] = lev.drawcol[lev.left + x];
+      lev.boomcol[lev.right + x] = lev.boomcol[lev.left + x];
     }
   }
 
-  temp = src[0x878] << 8 | src[0x879];
+  for (x = 0; x < lev.width; x++)
+    for (y = 0; y < lev.height; y++)
+      lev.cave[lev.left + x][lev.top + y] = map[cav.cave[x][y]];
 
-  if (temp & 1)
-  {
-    lev.android_array[Xemerald]                = Xemerald;
-    lev.android_array[Xemerald_pause]  = Xemerald;
-    lev.android_array[Xemerald_fall]   = Xemerald;
-    lev.android_array[Yemerald_sB]     = Xemerald;
-    lev.android_array[Yemerald_eB]     = Xemerald;
-    lev.android_array[Yemerald_wB]     = Xemerald;
-  }
-
-  if (temp & 2)
-  {
-    lev.android_array[Xdiamond]                = Xdiamond;
-    lev.android_array[Xdiamond_pause]  = Xdiamond;
-    lev.android_array[Xdiamond_fall]   = Xdiamond;
-    lev.android_array[Ydiamond_sB]     = Xdiamond;
-    lev.android_array[Ydiamond_eB]     = Xdiamond;
-    lev.android_array[Ydiamond_wB]     = Xdiamond;
-  }
-
-  if (temp & 4)
-  {
-    lev.android_array[Xstone]          = Xstone;
-    lev.android_array[Xstone_pause]    = Xstone;
-    lev.android_array[Xstone_fall]     = Xstone;
-    lev.android_array[Ystone_sB]       = Xstone;
-    lev.android_array[Ystone_eB]       = Xstone;
-    lev.android_array[Ystone_wB]       = Xstone;
-  }
-
-  if (temp & 8)
-  {
-    lev.android_array[Xbomb]           = Xbomb;
-    lev.android_array[Xbomb_pause]     = Xbomb;
-    lev.android_array[Xbomb_fall]      = Xbomb;
-    lev.android_array[Ybomb_sB]                = Xbomb;
-    lev.android_array[Ybomb_eB]                = Xbomb;
-    lev.android_array[Ybomb_wB]                = Xbomb;
-  }
-
-  if (temp & 16)
-  {
-    lev.android_array[Xnut]            = Xnut;
-    lev.android_array[Xnut_pause]      = Xnut;
-    lev.android_array[Xnut_fall]       = Xnut;
-    lev.android_array[Ynut_sB]         = Xnut;
-    lev.android_array[Ynut_eB]         = Xnut;
-    lev.android_array[Ynut_wB]         = Xnut;
-  }
-
-  if (temp & 32)
-  {
-    lev.android_array[Xtank_n]         = Xtank_n;
-    lev.android_array[Xtank_gon]       = Xtank_n;
-    lev.android_array[Ytank_nB]                = Xtank_n;
-    lev.android_array[Ytank_n_e]       = Xtank_n;
-    lev.android_array[Ytank_n_w]       = Xtank_n;
-
-    lev.android_array[Xtank_e]         = Xtank_e;
-    lev.android_array[Xtank_goe]       = Xtank_e;
-    lev.android_array[Ytank_eB]                = Xtank_e;
-    lev.android_array[Ytank_e_s]       = Xtank_e;
-    lev.android_array[Ytank_e_n]       = Xtank_e;
-
-    lev.android_array[Xtank_s]         = Xtank_s;
-    lev.android_array[Xtank_gos]       = Xtank_s;
-    lev.android_array[Ytank_sB]                = Xtank_s;
-    lev.android_array[Ytank_s_w]       = Xtank_s;
-    lev.android_array[Ytank_s_e]       = Xtank_s;
-
-    lev.android_array[Xtank_w]         = Xtank_w;
-    lev.android_array[Xtank_gow]       = Xtank_w;
-    lev.android_array[Ytank_wB]                = Xtank_w;
-    lev.android_array[Ytank_w_n]       = Xtank_w;
-    lev.android_array[Ytank_w_s]       = Xtank_w;
-  }
-
-  if (temp & 64)
-  {
-    lev.android_array[Xeater_n]                = Xeater_n;
-    lev.android_array[Yeater_nB]       = Xeater_n;
+  for (x = lev.left; x < lev.right; x++)
+    for (y = lev.top; y < lev.bottom; y++)
+      lev.next[x][y] = lev.draw[x][y] = lev.cave[x][y];
 
-    lev.android_array[Xeater_e]                = Xeater_e;
-    lev.android_array[Yeater_eB]       = Xeater_e;
-
-    lev.android_array[Xeater_s]                = Xeater_s;
-    lev.android_array[Yeater_sB]       = Xeater_s;
-
-    lev.android_array[Xeater_w]                = Xeater_w;
-    lev.android_array[Yeater_wB]       = Xeater_w;
-  }
-
-  if (temp & 128)
-  {
-    lev.android_array[Xbug_n]          = Xbug_gon;
-    lev.android_array[Xbug_gon]                = Xbug_gon;
-    lev.android_array[Ybug_nB]         = Xbug_gon;
-    lev.android_array[Ybug_n_e]                = Xbug_gon;
-    lev.android_array[Ybug_n_w]                = Xbug_gon;
-
-    lev.android_array[Xbug_e]          = Xbug_goe;
-    lev.android_array[Xbug_goe]                = Xbug_goe;
-    lev.android_array[Ybug_eB]         = Xbug_goe;
-    lev.android_array[Ybug_e_s]                = Xbug_goe;
-    lev.android_array[Ybug_e_n]                = Xbug_goe;
-
-    lev.android_array[Xbug_s]          = Xbug_gos;
-    lev.android_array[Xbug_gos]                = Xbug_gos;
-    lev.android_array[Ybug_sB]         = Xbug_gos;
-    lev.android_array[Ybug_s_w]                = Xbug_gos;
-    lev.android_array[Ybug_s_e]                = Xbug_gos;
-
-    lev.android_array[Xbug_w]          = Xbug_gow;
-    lev.android_array[Xbug_gow]                = Xbug_gow;
-    lev.android_array[Ybug_wB]         = Xbug_gow;
-    lev.android_array[Ybug_w_n]                = Xbug_gow;
-    lev.android_array[Ybug_w_s]                = Xbug_gow;
-  }
-
-  if (temp & 256)
-  {
-    lev.android_array[Xalien]          = Xalien;
-    lev.android_array[Xalien_pause]    = Xalien;
-    lev.android_array[Yalien_nB]       = Xalien;
-    lev.android_array[Yalien_eB]       = Xalien;
-    lev.android_array[Yalien_sB]       = Xalien;
-    lev.android_array[Yalien_wB]       = Xalien;
-  }
-
-  if (temp & 512)
-  {
-    lev.android_array[Xspring]         = Xspring;
-    lev.android_array[Xspring_pause]   = Xspring;
-    lev.android_array[Xspring_e]       = Xspring;
-    lev.android_array[Yspring_eB]      = Xspring;
-    lev.android_array[Yspring_kill_eB] = Xspring;
-    lev.android_array[Xspring_w]       = Xspring;
-    lev.android_array[Yspring_wB]      = Xspring;
-    lev.android_array[Yspring_kill_wB] = Xspring;
-    lev.android_array[Xspring_fall]    = Xspring;
-    lev.android_array[Yspring_sB]      = Xspring;
-  }
-
-  if (temp & 1024)
-  {
-    lev.android_array[Yballoon_nB]     = Xballoon;
-    lev.android_array[Yballoon_eB]     = Xballoon;
-    lev.android_array[Yballoon_sB]     = Xballoon;
-    lev.android_array[Yballoon_wB]     = Xballoon;
-    lev.android_array[Xballoon]                = Xballoon;
-  }
-
-  if (temp & 2048)
-  {
-    lev.android_array[Xdripper]                = Xdrip_eat;
-    lev.android_array[XdripperB]       = Xdrip_eat;
-    lev.android_array[Xamoeba_1]       = Xdrip_eat;
-    lev.android_array[Xamoeba_2]       = Xdrip_eat;
-    lev.android_array[Xamoeba_3]       = Xdrip_eat;
-    lev.android_array[Xamoeba_4]       = Xdrip_eat;
-    lev.android_array[Xamoeba_5]       = Xdrip_eat;
-    lev.android_array[Xamoeba_6]       = Xdrip_eat;
-    lev.android_array[Xamoeba_7]       = Xdrip_eat;
-    lev.android_array[Xamoeba_8]       = Xdrip_eat;
-  }
+  lev.time = cav.time_seconds;
+  lev.gems_needed = cav.gems_needed;
+  lev.score = 0;
 
-  if (temp & 4096)
-  {
-    lev.android_array[Xdynamite]       = Xdynamite;
-  }
+  lev.testmode = cav.testmode;
 
-  for (temp = 1; temp < 2047; temp++)
+  if (lev.testmode)
   {
-    switch (src[temp])
-    {
-      case 0x24:                               /* wonderwall */
-       lev.wonderwall_state_initial = 1;
-       lev.wonderwall_time_initial = 9999;
-       break;
-
-      case 0x28:                               /* wheel */
-       lev.wheel_x_initial = temp & 63;
-       lev.wheel_y_initial = temp >> 6;
-       lev.wheel_cnt_initial = lev.wheel_time;
-       break;
-
-#ifndef BAD_ROLL
-      case 0x63:                               /* spring roll left */
-       src[temp - 1] = 0x45;
-       src[temp] = 0x80;
-       break;
-
-      case 0x64:                               /* spring roll right */
-       src[temp + 1] = 0x45;
-       src[temp] = 0x80;
-       break;
-
-      case 0x72:                               /* nut roll left */
-       src[temp - 1] = 0x25;
-       src[temp] = 0x80;
-       break;
-
-      case 0x73:                               /* nut roll right */
-       src[temp + 1] = 0x25;
-       src[temp] = 0x80;
-       break;
-
-      case 0x77:                               /* bomb roll left */
-       src[temp - 1] = 0x10;
-       src[temp] = 0x80;
-       break;
-
-      case 0x78:                               /* bomb roll right */
-       src[temp + 1] = 0x10;
-       src[temp] = 0x80;
-       break;
-
-      case 0x79:                               /* stone roll left */
-       src[temp - 1] = 0x00;
-       src[temp] = 0x80;
-       break;
-
-      case 0x7A:                               /* stone roll right */
-       src[temp + 1] = 0x00;
-       src[temp] = 0x80;
-       break;
-#endif
-
-      case 0xA3:                               /* fake blank */
-       lev.lenses_cnt_initial = 9999;
-       break;
-
-      case 0xA4:                               /* fake grass */
-       lev.magnify_cnt_initial = 9999;
-       break;
-    }
+    lev.time = 0;
+    lev.gems_needed = 0;
   }
 
-  /* first fill the complete playfield with the default border element */
-  for (y = 0; y < HEIGHT; y++)
-    for (x = 0; x < WIDTH; x++)
-      native_em_level.cave[x][y] = ZBORDER;
-
-  /* then copy the real level contents from level file into the playfield */
-  temp = 0;
-  for (y = 0; y < lev.height; y++)
-    for (x = 0; x < lev.width; x++)
-      native_em_level.cave[x + 1][y + 1] = remap_emerald[src[temp++]];
-
-  /* at last, set the two players at their positions in the playfield */
-  /* (native EM[C] levels always have exactly two players in a level) */
-#if 1
-  for (i = 0; i < 2; i++)
-    native_em_level.cave[ply[i].x_initial][ply[i].y_initial] = Zplayer;
-#else
-  for (i = 0; i < 2; i++)
-    if (ply[i].alive_initial)
-      native_em_level.cave[ply[i].x_initial][ply[i].y_initial] = Zplayer;
-#endif
-
-  native_em_level.file_version = file_version;
-}
+  lev.eater_score      = cav.eater_score;
+  lev.alien_score      = cav.alien_score;
+  lev.bug_score                = cav.bug_score;
+  lev.tank_score       = cav.tank_score;
+  lev.emerald_score    = cav.emerald_score;
+  lev.diamond_score    = cav.diamond_score;
+  lev.nut_score                = cav.nut_score;
+  lev.slurp_score      = cav.slurp_score;
+  lev.dynamite_score   = cav.dynamite_score;
+  lev.key_score                = cav.key_score;
+  lev.lenses_score     = cav.lenses_score;
+  lev.magnify_score    = cav.magnify_score;
+  lev.exit_score       = cav.exit_score;
 
-void prepare_em_level(void)
-{
-  int i, x, y;
-  int players_left;
-  int num_tape_players;
+  lev.amoeba_time = cav.amoeba_time;
 
-  /* reset all runtime variables to their initial values */
+  lev.android_move_time = cav.android_move_time;
+  lev.android_move_cnt  = cav.android_move_time;
 
-  for (y = 0; y < HEIGHT; y++)
-    for (x = 0; x < WIDTH; x++)
-      Cave[y][x] = native_em_level.cave[x][y];
+  lev.android_clone_time = cav.android_clone_time;
+  lev.android_clone_cnt  = cav.android_clone_time;
 
-  for (y = 0; y < HEIGHT; y++)
-    for (x = 0; x < WIDTH; x++)
-      Next[y][x] = Cave[y][x];
+  lev.ball_time   = cav.ball_time;
+  lev.ball_cnt    = cav.ball_time;
+  lev.ball_active = cav.ball_active;
+  lev.ball_random = cav.ball_random;
+  lev.ball_pos    = 0;
 
-  for (y = 0; y < HEIGHT; y++)
-    for (x = 0; x < WIDTH; x++)
-      Draw[y][x] = Cave[y][x];
+  lev.eater_pos = 0;
+  lev.shine_cnt = 0;
 
-#if 1
-  lev.time_initial = lev.time_seconds;
-#else
-  lev.time_initial = (lev.time_seconds * 50 + 7) / 8;
-#endif
-  lev.time = lev.time_initial;
+  lev.lenses_time = cav.lenses_time;
+  lev.lenses_cnt  = cav.lenses_active ? cav.lenses_time : 0;
 
-  lev.required = lev.required_initial;
-  lev.score = 0;
+  lev.magnify_time = cav.magnify_time;
+  lev.magnify_cnt  = cav.magnify_active ? cav.magnify_time : 0;
 
-  lev.android_move_cnt  = lev.android_move_time;
-  lev.android_clone_cnt = lev.android_clone_time;
+  lev.wheel_time = cav.wheel_time;
+  lev.wheel_cnt  = cav.wheel_active ? cav.wheel_time : 0;
+  lev.wheel_x    = cav.wheel_x;
+  lev.wheel_y    = cav.wheel_y;
 
-  lev.ball_pos = 0;
-  lev.ball_state = lev.ball_state_initial;
-  lev.ball_cnt = lev.ball_time;
+  lev.wind_time      = cav.wind_time;
+  lev.wind_cnt       = cav.wind_time;
+  lev.wind_direction = cav.wind_direction;
 
-  lev.eater_pos = 0;
-  lev.shine_cnt = 0;
+  lev.wonderwall_time   = cav.wonderwall_time;
+  lev.wonderwall_active = cav.wonderwall_active;
 
-  lev.lenses_cnt = lev.lenses_cnt_initial;
-  lev.magnify_cnt = lev.magnify_cnt_initial;
+  lev.killed_out_of_time = FALSE;
 
-  lev.wheel_cnt = lev.wheel_cnt_initial;
-  lev.wheel_x   = lev.wheel_x_initial;
-  lev.wheel_y   = lev.wheel_y_initial;
+  lev.num_ball_arrays = cav.num_ball_arrays;
 
-  lev.wind_direction = lev.wind_direction_initial;
-  lev.wind_cnt       = lev.wind_cnt_initial;
+  for (i = 0; i < 8; i++)
+    for (j = 0; j < 9; j++)
+      lev.eater_array[i][j] = map[cav.eater_array[i][j]];
 
-  lev.wonderwall_state = lev.wonderwall_state_initial;
-  lev.wonderwall_time  = lev.wonderwall_time_initial;
+  for (i = 0; i < 8; i++)
+    for (j = 0; j < 8; j++)
+      lev.ball_array[i][j] = map[cav.ball_array[i][j]];
 
-  lev.killed_out_of_time = FALSE;
+  for (i = 0; i < GAME_TILE_MAX; i++)
+    lev.android_array[i] = map[cav.android_array[i]];
 
-  /* determine number of players in this level */
   lev.home_initial = 0;
 
+  /* check for players in this level */
   for (i = 0; i < MAX_PLAYERS; i++)
   {
-    ply[i].exists = 0;
-    ply[i].alive_initial = FALSE;
+    ply[i].exists = FALSE;
+    ply[i].alive = FALSE;
 
-    if (ply[i].x_initial > 0 && ply[i].y_initial > 0)
+    if (cav.player_x[i] != -1 &&
+       cav.player_y[i] != -1)
     {
-      ply[i].exists = 1;
+      ply[i].exists = TRUE;
 
       lev.home_initial++;
     }
   }
 
-  num_tape_players = getActivePlayers_EM();
+  team_mode = getTeamMode_EM();
 
-  if (num_tape_players != -1)
-    lev.home_initial = MIN(lev.home_initial, num_tape_players);
-  else if (!setup.team_mode)
-    lev.home_initial = MIN(lev.home_initial, 1);
+  if (!team_mode)
+    lev.home_initial = 1;
 
   lev.home = lev.home_initial;
   players_left = lev.home_initial;
 
+  /* assign active players */
   for (i = 0; i < MAX_PLAYERS; i++)
   {
-    if (ply[i].exists)
+    if (ply[i].exists && isActivePlayer_EM(i))
     {
       if (players_left)
       {
-       ply[i].alive_initial = TRUE;
+       ply[i].alive = TRUE;
        players_left--;
       }
-      else
-      {
-       int x = ply[i].x_initial;
-       int y = ply[i].y_initial;
+    }
+  }
 
-       native_em_level.cave[x][y] = Xblank;
+  /* remove inactive players */
+  for (i = 0; i < MAX_PLAYERS; i++)
+  {
+    if (ply[i].exists && !ply[i].alive)
+    {
+      int x = cav.player_x[i];
+      int y = cav.player_y[i];
 
-       Cave[y][x] = Next[y][x] = Draw[y][x] = Xblank;
-      }
+      lev.cave[lev.left + x][lev.top + y] = Xblank;
+      lev.next[lev.left + x][lev.top + y] = Xblank;
+      lev.draw[lev.left + x][lev.top + y] = Xblank;
     }
   }
 
   for (i = 0; i < MAX_PLAYERS; i++)
   {
     ply[i].num = i;
-    ply[i].alive = ply[i].alive_initial;
-    ply[i].dynamite = 0;
-    ply[i].dynamite_cnt = 0;
-    ply[i].keys = 0;
-    ply[i].anim = 0;
-    ply[i].oldx = ply[i].x = ply[i].x_initial;
-    ply[i].oldy = ply[i].y = ply[i].y_initial;
+    ply[i].anim = PLY_still;
+
+    ply[i].x = cav.player_x[i] + lev.left;
+    ply[i].y = cav.player_y[i] + lev.top;
+    ply[i].prev_x = ply[i].x;
+    ply[i].prev_y = ply[i].y;
+
+    ply[i].dynamite    = 0;
+    ply[i].dynamite_cnt        = 0;
+    ply[i].keys                = 0;
+
     ply[i].last_move_dir = MV_NONE;
-    ply[i].joy_n = ply[i].joy_e = ply[i].joy_s = ply[i].joy_w = 0;
-    ply[i].joy_snap  = ply[i].joy_drop = 0;
-    ply[i].joy_stick = ply[i].joy_spin = 0;
-
-#if 0
-    printf("player %d: x/y == %d/%d, alive == %d\n",
-          i, ply[i].x_initial, ply[i].y_initial, ply[i].alive);
-#endif
+
+    ply[i].joy_n       = FALSE;
+    ply[i].joy_e       = FALSE;
+    ply[i].joy_s       = FALSE;
+    ply[i].joy_w       = FALSE;
+    ply[i].joy_snap    = FALSE;
+    ply[i].joy_drop    = FALSE;
+    ply[i].joy_stick   = FALSE;
   }
 
+  // the following engine variables are initialized to version-specific values
+  // in function InitGameEngine() (src/game.c):
+  //
+  // - game_em.use_single_button (default: TRUE)
+  // - game_em.use_snap_key_bug (default: FALSE)
+  // - game_em.use_old_explosions (default: FALSE)
+  // - game_em.use_wrap_around (default: TRUE)
+
+  game_em.level_solved = FALSE;
+  game_em.game_over = FALSE;
+
   game_em.any_player_moving = FALSE;
+  game_em.any_player_snapping = FALSE;
+
   game_em.last_moving_player = 0;      /* default: first player */
 
   for (i = 0; i < MAX_PLAYERS; i++)
     game_em.last_player_direction[i] = MV_NONE;
+
+  lev.exit_x = lev.exit_y = -1;        /* kludge for playing player exit sound */
 }