Monster vision enchantment and evaluation

doc/MAGIC.md

@@ -956,6 +956,7 @@ Character status value  | Description
 `ARMOR_HEAT`            | 
 `ARMOR_STAB`            | 
 `REGEN_HP`              | Affects the rate the monster recovers hp.
+`VISION_RANGE`          | Affects monster vision range, both day and night one.
 `SPEED`                 | Affects the base speed of the monster.
 `LUMINATION`            | Affects monster luminance
 

doc/NPCs.md

@@ -1383,7 +1383,7 @@ _some functions support array arguments or kwargs, denoted with square brackets
 | npc_value()    |  ✅   |  ✅   | u, n  | Return NPC value toward opposite talker. <br/><br/>Example:<br/> `{ "math": [ "n_npc_value()", "+=", "2" ] }`|
 | vitamin(`s`/`v`)    |  ✅   |   ✅  | u, n  | Return or set the characters vitamin level.<br/>Argument is vitamin ID.<br/><br/>Example:<br/>`{ "math": [ "u_vitamin('mutagen')", "=", "0" ] }`|
 | warmth(`s`/`v`)    |  ✅   |   ❌  | u, n  | Return the characters warmth on a body part.<br/>Argument is bodypart ID.<br/><br/>Example:<br/> The value displayed in-game is calculated as follows.<br/> `"{ "math": [ "u_warmth_in_game", "=", "(u_warmth('torso') / 100) * 2 - 100"] }`|
-| vision_range()    |  ✅   |   ❌  | u, n  | Return the character's visual range, adjusted by their mutations, effects, and other issues.<br/><br/>Example:<br/> `"{ "math": [ "u_vision_range", "<", "30"] }`|
+| vision_range()    |  ✅   |   ❌  | u, n  | Return the character's or monsters visual range, adjusted by their mutations, effects, and other issues.<br/><br/>Example:<br/> `"{ "math": [ "n_vision_range()", "<", "30"] }`|
 | weather(`s`)  |  ✅  |   ✅   | N/A<br/>(global)  | Return or set a weather aspect<br/><br/>Aspect must be one of:<br/>`temperature` (in Kelvin),<br/>`humidity` (as percentage),<br/>`pressure` (in millibar),<br/>`windpower` (in mph).<br/>`precipitation` (in mm / h) either 0.5 (very_light ), 1.5 (light), or 3 (heavy). Read only.<br/><br/>Temperature conversion functions are available: `celsius()`, `fahrenheit()`, `from_celsius()`, and `from_fahrenheit()`.<br/><br/>Examples:<br/>`{ "math": [ "weather('temperature')", "<", "from_fahrenheit( 33 )" ] }`<br/>`{ "math": [ "fahrenheit( weather('temperature') )", "==", "21" ] }`|
 | damage_level()    |  ✅   |   ❌  | u, n  | Return the damage level of the talker, which must be an item.<br/><br/>Example:<br/>`"condition": { "math": [ "n_damage_level()", "<", "1" ] }`|
 | climate_control_str_heat()    |  ✅   |   ❌  | u, n  | return amount of heat climate control that character currently has (character feels better in warm places with it), in warmth points; default 0, affected by CLIMATE_CONTROL_HEAT enchantment.<br/><br/>Example:<br/>`"condition": { "math": [ "u_climate_control_str_heat()", "<", "0" ] }`|

src/magic_enchantment.cpp

@@ -95,6 +95,7 @@ namespace io
             case enchant_vals::mod::ATTACK_NOISE: return "ATTACK_NOISE";
             case enchant_vals::mod::SHOUT_NOISE: return "SHOUT_NOISE";
             case enchant_vals::mod::FOOTSTEP_NOISE: return "FOOTSTEP_NOISE";
+            case enchant_vals::mod::VISION_RANGE: return "VISION_RANGE";
             case enchant_vals::mod::SIGHT_RANGE_ELECTRIC: return "SIGHT_RANGE_ELECTRIC";
             case enchant_vals::mod::MOTION_VISION_RANGE: return "MOTION_VISION_RANGE";
             case enchant_vals::mod::SIGHT_RANGE_FAE: return "SIGHT_RANGE_FAE";
@@ -324,6 +325,7 @@ bool enchantment::is_monster_relevant() const
             pair_values.first == enchant_vals::mod::ARMOR_HEAT ||
             pair_values.first == enchant_vals::mod::ARMOR_STAB ||
             pair_values.first == enchant_vals::mod::REGEN_HP ||
+            pair_values.first == enchant_vals::mod::VISION_RANGE ||
             pair_values.first == enchant_vals::mod::SPEED ||
             pair_values.first == enchant_vals::mod::LUMINATION ) {
             return true;
@@ -344,6 +346,7 @@ bool enchantment::is_monster_relevant() const
             pair_values.first == enchant_vals::mod::ARMOR_HEAT ||
             pair_values.first == enchant_vals::mod::ARMOR_STAB ||
             pair_values.first == enchant_vals::mod::REGEN_HP ||
+            pair_values.first == enchant_vals::mod::VISION_RANGE ||
             pair_values.first == enchant_vals::mod::SPEED ||
             pair_values.first == enchant_vals::mod::LUMINATION ) {
             return true;

src/magic_enchantment.h

@@ -71,6 +71,7 @@ enum class mod : int {
     ATTACK_NOISE,
     SHOUT_NOISE,
     FOOTSTEP_NOISE,
+    VISION_RANGE,
     SIGHT_RANGE_ELECTRIC,
     MOTION_VISION_RANGE,
     SIGHT_RANGE_FAE,

src/math_parser_diag.cpp

@@ -1478,6 +1478,10 @@ std::function<double( dialogue & )> vision_range_eval( char scope,
         talker const *const actor = d.actor( beta );
         if( Character const *const chr = actor->get_character(); chr != nullptr ) {
             return chr->unimpaired_range();
+        } else if( monster const *const mon = actor->get_monster(); mon != nullptr ) {
+            map &here = get_map();
+            tripoint_bub_ms tripoint = get_map().bub_from_abs( mon->get_location() );
+            return mon->sight_range( here.ambient_light_at( tripoint ) );
         }
         debugmsg( "Tried to access vision range of a non-Character talker" );
         return 0;

src/monster.cpp

@@ -1385,13 +1385,15 @@ int monster::sight_range( const float light_level ) const
     }
     static const float default_daylight = default_daylight_level();
     if( light_level == 0 ) {
-        return type->vision_night;
+        return calculate_by_enchantment( type->vision_night, enchant_vals::mod::VISION_RANGE, true );
     } else if( light_level >= default_daylight ) {
-        return type->vision_day;
+        return calculate_by_enchantment( type->vision_day, enchant_vals::mod::VISION_RANGE, true );
     }
     int range = ( light_level * type->vision_day + ( default_daylight - light_level ) *
                   type->vision_night ) / default_daylight;
 
+    range = calculate_by_enchantment( range, enchant_vals::mod::VISION_RANGE, true );
+
     return range;
 }