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TECHNICAL INFORMATION ABOUT MAPS: |
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|
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This documented is intended to convey technical information on how |
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crossfire deals with the map objects and objects placed on the maps. For |
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the most part, I only intend document how the new code works, and not |
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go too much into history on the older methods. A lot of the map |
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code was re-written in early July 2001, which changed how many things are |
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dealt with. |
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|
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Mark Wedel |
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July 7, 2001 |
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|
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------------------------------------------------------------------------------ |
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THE MAP HEADER: |
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|
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The map header is the section at the start of the map file that |
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describes the maps characteristics. The values are described below. |
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|
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The map variables now make some sense, and are only stored in the |
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map structure itself. I still include the old value (the 'was') so |
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if you are looking at old maps, you know what they mean. Generally |
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speaking, the values in the map files themselves match the same element |
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name in the map structure. |
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|
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'width','height', was 'x','y': Size of the map. |
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|
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'enter_x', 'enter_y', was ('hp','sp') = (x,y) of the destination on the |
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new map. These are only used if the exit does not have a specific |
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location set. |
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|
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'reset_timeout', was 'weight': stores the number of seconds that need |
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to elapse before this map will be reset. Ie, if 1800, it means this |
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map expires after 30 minutes. This value is not modified once loaded - |
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instead reset_time is used to track this. The value 0 means to use |
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a default timeout (MAP_DEFAULTRESET). |
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|
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'swap_time', was 'value': This controls how many ticks must elapse |
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after the map has not been used before it gets swapped out. |
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swapping out is different than reset, as a swapped out map will |
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get loaded back into memory if someone re-visits it before it is due to |
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reset. |
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|
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'difficulty', was 'level' stores the map difficulty. If not set to |
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anything, the server code will try to come up with some difficulty value. |
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|
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'fixed_resettime', was 'stand_still': If nonzero, the map reset time will not |
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be updated when someone enters/exits the map. Thus, once the map has |
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been loaded, it will reset in 'reset time' no matter what access |
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happen. This is useful for shops and towns, which are constantly |
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accessed, but should be reset periodically. |
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|
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'darkness', was 'invisible'. Light/darnkess of map (overall). If 0, |
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all of map is fully bright. |
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|
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'unique' - if set, this entire map is unique. Exactly unique to what |
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will depend on how it was created (it could be a per player |
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unique map, or maybe a common map that is just permanent for |
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all the players. |
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|
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'outdoor' - if set, this is a hint that this is an outdoor map. |
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If this is not set, weather and dawn/dusk will not occur on this |
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map. It is highly advised that this be set appropriately. |
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|
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tile_path_<x> - Used with map tiling. <x> is a number, 1 is north, |
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2 is east, 3 south, 4 west. This determines what map is tiled |
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in that direction. See the section below for more information about |
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map tiling. |
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|
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'shopitems', 'shopgreed', 'shoprace', 'shopmin', 'shopmax' - the type of thing |
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the shop trades in, see doc/Developers/shops for more details |
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|
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'temp' - The base temperature in farenhiet for this map. The temperature |
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is modified by the season and weather conditions. In a map without |
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weather effects, this temperature will be used as the static |
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temperature for the entire map. This can be useful to make an ice |
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cave actually cold. |
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|
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'pressure' - This should really never be set on a map. The pressure in |
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millibars. |
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|
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'humid' - Again, should rarely be set on a map. The humidity in percent. |
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|
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'windspeed' - Rarely set. The windspeed in kph/h. |
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|
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'winddir' - Rarely set. Direction of wind, 1-8, 1 is north, clockwise. |
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|
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'sky' - The sky conditions for this map. See weather.h. Don't set this |
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unless you really know what you are doing. |
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|
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------------------------------------------------------------------------------ |
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THE MAP OBJECTS: |
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|
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The objects within the map are saved in standard 'object save' form |
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(same as is used for the players objects). Other files document the |
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actual meaning, but the general form is: |
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|
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arch <some name> |
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x <some value> |
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y <some value> |
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<other object specific values> |
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end |
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|
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Note that x and y are in fact optional. If not present, the values |
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default to zero. |
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|
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Multipart objects: |
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|
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Multipart objects pose a tricky problem, in that they have to |
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appear together in the map file - this makes proper handling of |
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layers hard to deal with. |
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|
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In old map code, all the single spaces objects were saved, and |
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then all the multi part objects were saved. This effectively |
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means that the multi part objects always ended up on top. The multipart |
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objects were saved with all their parts. For example: |
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|
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slaying shops/magicshop |
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hp 14 |
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sp 14 |
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x 1 |
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y 13 |
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end |
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More |
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arch store_magic_2 |
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name Magic Shop |
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slaying shops/magicshop |
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hp 14 |
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sp 14 |
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x 2 |
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y 13 |
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end |
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<snip - there are really two more parts> |
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|
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This method does not work very well with the map tiling however (how do you |
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reasonably deal with a monster that may be straddling the two maps?) Current |
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code now only saves the head of the object. When the map is loaded, the |
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objects on the map are examined to see what objects need to have more objects |
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added on. Additional parts linked in are put just above floor level when |
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linked in, so things like shops won't hide items that someone drops on them. |
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For monsters, this linking shouldn't be a problem - once they start moving, |
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they will get relinked as normal (on top). |
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|
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The effect of saving only the head does have the effect of not being |
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able to customize the non head parts of the object. This generally should not |
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be a problem (in the case of shops/building, the exit code now knows to look |
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only at the head for valid information). The case where this may not work as |
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well as expected is for buildings where setting the no_pass to non |
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archetype defaults will get lost. |
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|
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------------------------------------------------------------------------------ |
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Map Tiling: |
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|
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Map tiling is a feature that lets multiple maps be connected, effectively |
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forming a much larger single map. This is most useful for the outdoor |
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world maps, where it is not practical to have on massive map, but |
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the old style tiling method (copying areas of the adjoining map to the next |
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one) are not very efficient. |
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|
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The transfer of objects from one map to another tiled map are automatic. |
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Presuming the proper macros are used (out_of_map, get_map_..), minimal extra |
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work is necessary for everything to work right |
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|
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Notes: |
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Tiled maps must be the same width/height along the side they are tiled with. |
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If map1 has a height of 15, and you want to tile along one of the sides, the |
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map(s) it gets tiled with along that side should also be 15. Given |
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the following diagram (not to scale): |
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|
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|
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+---x1----+----x2---+ |
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| | | |
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| map1 | map2 y2 |
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y1 | | |
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| | | |
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+---------+---------+ |
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|
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x1 is the width of map1, y1 is its height. |
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x2 is the width of map2, y2 is its height. |
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map1 will tile map2 as indicated in the above diagram. |
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|
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Given that, the following must be true: |
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y1 must equal y2 |
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x1 must be greater than 12 |
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x2 must be greater than 12 |
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x1 and x2 do not need to be equal |
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|
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The value is derived as being half the maximum viewable area. The reason |
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for this is that the line of sight code (and likely some other code) will only |
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look one map away from a source coordinate. While the values can be less |
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than 12, they should be at least 12 if the map tiles with another one in |
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that direction. If the map is an 'end' map (ie, no further tiling in a |
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specific direction), then having a value less than 12 should work just fine. |
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|
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Note that tiles maps do not have to be symmetric - several maps |
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could tile to a common map. That common map can only tile back to one of |
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those. And example of where this might be used is for a courtyard of |
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a multi floor house - that courtyard should be visible (and be the same) |
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from all the levels, but you can only go from the courtyard to first floor |
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rooms off the courtyard. This may not be ideal (ie, if flying, you should |
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be able to go to any floor), but this tiling for elevation is just an |
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example that can be used. |
