From 27343e3253b2693339f6a4356b6f2a118238d173 Mon Sep 17 00:00:00 2001
From: lethosor <lethosor@gmail.com>
Date: Sat, 10 Jun 2017 21:54:08 -0400
Subject: [PATCH] Add unit and tile visibility functions

---
 docs/Lua API.rst                |  8 ++++++++
 library/LuaApi.cpp              |  9 +++++++++
 library/include/modules/Maps.h  |  3 +++
 library/include/modules/Units.h |  1 +
 library/modules/Maps.cpp        | 11 +++++++++++
 library/modules/Units.cpp       |  7 +++++++
 6 files changed, 39 insertions(+)

diff --git a/docs/Lua API.rst b/docs/Lua API.rst
index 0e242a815..fb09f96fd 100644
--- a/docs/Lua API.rst	
+++ b/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.
diff --git a/library/LuaApi.cpp b/library/LuaApi.cpp
index af6e03676..38319dcfc 100644
--- a/library/LuaApi.cpp
+++ b/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 },
diff --git a/library/include/modules/Maps.h b/library/include/modules/Maps.h
index af3a9f5d5..fb5fc9860 100644
--- a/library/include/modules/Maps.h
+++ b/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
  */
diff --git a/library/include/modules/Units.h b/library/include/modules/Units.h
index 41859e983..7394c5300 100644
--- a/library/include/modules/Units.h
+++ b/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);
diff --git a/library/modules/Maps.cpp b/library/modules/Maps.cpp
index e9674437a..af2cd5183 100644
--- a/library/modules/Maps.cpp
+++ b/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))
diff --git a/library/modules/Units.cpp b/library/modules/Units.cpp
index ffec94910..41e9f2eba 100644
--- a/library/modules/Units.cpp
+++ b/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)
 {