Fix several pets AI bugs, add player homeostatic effect on pets

data/json/monsters/mammal.json

@@ -1668,15 +1668,14 @@
     "material": [ "flesh" ],
     "symbol": "H",
     "color": "brown",
-    "morale": 20,
     "melee_skill": 6,
     "melee_dice": 2,
     "melee_dice_sides": 12,
     "melee_cut": 0,
     "dodge": 2,
     "armor_bash": 2,
     "anger_triggers": [ "FRIEND_ATTACKED" ],
-    "fear_triggers": [ "SOUND", "PLAYER_CLOSE" ],
+    "fear_triggers": [ "PLAYER_CLOSE" ],
     "placate_triggers": [ "PLAYER_WEAK" ],
     "death_function": [ "NORMAL" ],
     "harvest": "mammal_large_leather",

src/character.cpp

@@ -10598,4 +10598,4 @@ bool has_psy_protection( const Character &c, int partial_chance )
 {
     return c.has_artifact_with( AEP_PSYSHIELD ) ||
            ( c.worn_with_flag( "PSYSHIELD_PARTIAL" ) && one_in( partial_chance ) );
-}
+}

src/monmove.cpp

@@ -581,12 +581,33 @@ void monster::plan()
     } else if( friendly > 0 && one_in( 3 ) ) {
         // Grow restless with no targets
         friendly--;
-    } else if( friendly < 0 && sees( g->u ) && !has_flag( MF_PET_WONT_FOLLOW ) ) {
-        if( rl_dist( pos(), g->u.pos() ) > 2 ) {
-            set_dest( g->u.pos() );
+        // if no target, and friendly pet sees the player
+    } else if( friendly < 0 && sees( g->u ) ) {
+        // eg dogs
+        if( !has_flag( MF_PET_WONT_FOLLOW ) ) {
+            // if too far from the player, go to him
+            if( rl_dist( pos(), g->u.pos() ) > 2 ) {
+                set_dest( g->u.pos() );
+            } else {
+                unset_dest();
+            }
+            // eg cows, horses
         } else {
             unset_dest();
         }
+        // when the players is close to their pet, it calms them
+        // it helps them reach an homeostatic state, for moral and anger
+        const int distance_from_friend = rl_dist( pos(), get_avatar().pos() );
+        if( distance_from_friend < 12 ) {
+            if( one_in( distance_from_friend * 3 ) ) {
+                if( morale != type->morale ) {
+                    morale += ( morale < type->morale ) ? 1 : -1;
+                }
+                if( anger != type->agro ) {
+                    anger += ( anger < type->agro ) ? 1 : -1;
+                }
+            }
+        }
     }
 
     // being led by a leash override other movements decisions

src/monster.cpp

@@ -1190,7 +1190,7 @@ monster_attitude monster::attitude( const Character *u ) const
     }
 
     if( effective_anger <= 0 ) {
-        if( get_hp() != get_hp_max() ) {
+        if( get_hp() <= 0.6 * get_hp_max() ) {
             return MATT_FLEE;
         } else {
             return MATT_IGNORE;
@@ -2587,8 +2587,8 @@ void monster::process_effects_internal()
         }
     }
 
-    //Monster will regen morale and aggression if it is on max HP
-    //It regens more morale and aggression if is currently fleeing.
+    // Monster will regen morale and aggression if it is on max HP
+    // It regens more morale and aggression if is currently fleeing.
     if( type->regen_morale && hp >= type->hp ) {
         if( is_fleeing( g->u ) ) {
             morale = type->morale;
@@ -2959,6 +2959,7 @@ void monster::hear_sound( const tripoint &source, const int vol, const int dist
     // target_z will require some special check due to soil muffling sounds
 
     int wander_turns = volume * ( goodhearing ? 6 : 1 );
+
     process_trigger( mon_trigger::SOUND, volume );
     if( morale >= 0 && anger >= 10 ) {
         // TODO: Add a proper check for fleeing attitude