Add unit and tile visibility functions

docs/Lua API.rst

@@ -1135,6 +1135,10 @@ Units module
   The unit is an alive sane citizen of the fortress; wraps the
   same checks the game uses to decide game-over by extinction.
 
+* ``dfhack.units.isVisible(unit)``
+
+  The unit is visible on the map.
+
 * ``dfhack.units.getAge(unit[,true_age])``
 
   Returns the age of the unit in years as a floating-point value.
@@ -1300,6 +1304,10 @@ Maps module
 
   Checks if the given df::coord or x,y,z in local tile coordinates are valid.
 
+* ``dfhack.maps.isTileVisible(coords)``, or ``isTileVisible(x,y,z)``
+
+  Checks if the given df::coord or x,y,z in local tile coordinates is visible.
+
 * ``dfhack.maps.getTileBlock(coords)``, or ``getTileBlock(x,y,z)``
 
   Returns a map block object for given df::coord or x,y,z in local tile coordinates.

library/LuaApi.cpp

@@ -1572,6 +1572,7 @@ static const LuaWrapper::FunctionReg dfhack_units_module[] = {
     WRAPM(Units, isSane),
     WRAPM(Units, isDwarf),
     WRAPM(Units, isCitizen),
+    WRAPM(Units, isVisible),
     WRAPM(Units, getAge),
     WRAPM(Units, getKillCount),
     WRAPM(Units, getNominalSkill),
@@ -1818,6 +1819,13 @@ static int maps_isValidTilePos(lua_State *L)
     return 1;
 }
 
+static int maps_isTileVisible(lua_State *L)
+{
+    auto pos = CheckCoordXYZ(L, 1, true);
+    lua_pushboolean(L, Maps::isTileVisible(pos));
+    return 1;
+}
+
 static int maps_getTileBlock(lua_State *L)
 {
     auto pos = CheckCoordXYZ(L, 1, true);
@@ -1866,6 +1874,7 @@ static int maps_getTileBiomeRgn(lua_State *L)
 
 static const luaL_Reg dfhack_maps_funcs[] = {
     { "isValidTilePos", maps_isValidTilePos },
+    { "isTileVisible", maps_isTileVisible },
     { "getTileBlock", maps_getTileBlock },
     { "ensureTileBlock", maps_ensureTileBlock },
     { "getTileType", maps_getTileType },

library/include/modules/Maps.h

@@ -263,6 +263,9 @@ extern DFHACK_EXPORT void getPosition(int32_t& x, int32_t& y, int32_t& z);
 extern DFHACK_EXPORT bool isValidTilePos(int32_t x, int32_t y, int32_t z);
 inline bool isValidTilePos(df::coord pos) { return isValidTilePos(pos.x, pos.y, pos.z); }
 
+extern DFHACK_EXPORT bool isTileVisible(int32_t x, int32_t y, int32_t z);
+inline bool isTileVisible(df::coord pos) { return isTileVisible(pos.x, pos.y, pos.z); }
+
 /**
  * Get the map block or NULL if block is not valid
  */

library/include/modules/Units.h

@@ -116,6 +116,7 @@ DFHACK_EXPORT bool isAvailableForAdoption(df::unit* unit);
 DFHACK_EXPORT bool isOwnCiv(df::unit* unit);
 DFHACK_EXPORT bool isOwnGroup(df::unit* unit);
 DFHACK_EXPORT bool isOwnRace(df::unit* unit);
+DFHACK_EXPORT bool isVisible(df::unit* unit);
 
 DFHACK_EXPORT std::string getRaceNameById(int32_t race_id);
 DFHACK_EXPORT std::string getRaceName(df::unit* unit);

library/modules/Maps.cpp

@@ -166,6 +166,17 @@ bool Maps::isValidTilePos(int32_t x, int32_t y, int32_t z)
     return true;
 }
 
+bool Maps::isTileVisible(int32_t x, int32_t y, int32_t z)
+{
+    df::map_block *block = getTileBlock(x, y, z);
+    if (!block)
+        return false;
+    if (block->designation[x % 16][y % 16].bits.hidden)
+        return false;
+
+    return true;
+}
+
 df::map_block *Maps::getTileBlock (int32_t x, int32_t y, int32_t z)
 {
     if (!isValidTilePos(x,y,z))

library/modules/Units.cpp

@@ -42,6 +42,7 @@ using namespace std;
 // we connect to those
 #include "modules/Units.h"
 #include "modules/Items.h"
+#include "modules/Maps.h"
 #include "modules/Materials.h"
 #include "modules/Translation.h"
 #include "ModuleFactory.h"
@@ -526,6 +527,12 @@ bool Units::isOwnRace(df::unit* unit)
     return unit->race == ui->race_id;
 }
 
+bool Units::isVisible(df::unit* unit)
+{
+    CHECK_NULL_POINTER(unit);
+    return Maps::isTileVisible(unit->pos);
+}
+
 // get race name by id or unit pointer
 string Units::getRaceNameById(int32_t id)
 {