+ /* number of special ("gravity") port entries below (maximum 10 allowed) */
+ num_special_ports = fgetc(file);
+
+ /* database of properties of up to 10 special ports (6 bytes per port) */
+ for (i = 0; i < 10; i++)
+ {
+ int port_location, port_x, port_y, port_element;
+ int gravity;
+
+ /* high and low byte of the location of a special port; if (x, y) are the
+ coordinates of a port in the field and (0, 0) is the top-left corner,
+ the 16 bit value here calculates as 2 * (x + (y * 60)) (this is twice
+ of what may be expected: Supaplex works with a game field in memory
+ which is 2 bytes per tile) */
+ port_location = getFile16BitBE(file);
+
+ /* change gravity: 1 == "turn on", anything else (0) == "turn off" */
+ gravity = fgetc(file);
+
+ /* "freeze zonks": 2 == "turn on", anything else (0, 1) == "turn off" */
+ ReadUnusedBytesFromFile(file, 1); /* (not used by R'n'D engine) */
+
+ /* "freeze enemies": 1 == "turn on", anything else (0) == "turn off" */
+ ReadUnusedBytesFromFile(file, 1); /* (not used by R'n'D engine) */
+
+ ReadUnusedBytesFromFile(file, 1); /* (not used by Supaplex engine) */
+
+ if (i >= num_special_ports)
+ continue;
+
+ port_x = (port_location / 2) % SP_LEVEL_XSIZE;
+ port_y = (port_location / 2) / SP_LEVEL_XSIZE;
+
+ if (port_x < 0 || port_x >= SP_LEVEL_XSIZE ||
+ port_y < 0 || port_y >= SP_LEVEL_YSIZE)
+ {
+ Error(ERR_WARN, "special port position (%d, %d) out of bounds",
+ port_x, port_y);
+
+ continue;
+ }
+
+ port_element = level->field[port_x][port_y];
+
+ if (port_element < EL_SP_GRAVITY_PORT_RIGHT ||
+ port_element > EL_SP_GRAVITY_PORT_UP)
+ {
+ Error(ERR_WARN, "no special port at position (%d, %d)", port_x, port_y);
+
+ continue;
+ }
+
+ /* change previous (wrong) gravity inverting special port to either
+ gravity enabling special port or gravity disabling special port */
+ level->field[port_x][port_y] +=
+ (gravity == 1 ? EL_SP_GRAVITY_ON_PORT_RIGHT :
+ EL_SP_GRAVITY_OFF_PORT_RIGHT) - EL_SP_GRAVITY_PORT_RIGHT;
+ }
+
+ ReadUnusedBytesFromFile(file, 4); /* (not used by Supaplex engine) */
+
+ /* change special gravity ports without database entries to normal ports */
+ for (y = 0; y < SP_LEVEL_YSIZE; y++)
+ for (x = 0; x < SP_LEVEL_XSIZE; x++)
+ if (level->field[x][y] >= EL_SP_GRAVITY_PORT_RIGHT &&
+ level->field[x][y] <= EL_SP_GRAVITY_PORT_UP)
+ level->field[x][y] += EL_SP_PORT_RIGHT - EL_SP_GRAVITY_PORT_RIGHT;
+
+ /* auto-determine number of infotrons if it was stored as "0" -- see above */
+ if (level->gems_needed == 0)
+ {
+ for (y = 0; y < SP_LEVEL_YSIZE; y++)
+ for (x = 0; x < SP_LEVEL_XSIZE; x++)
+ if (level->field[x][y] == EL_SP_INFOTRON)
+ level->gems_needed++;
+
+ level->gems_needed &= 0xff; /* only use low byte -- see above */
+ }