Monster behavior tree

data/json/monsters/monster_goals.json

@@ -0,0 +1,27 @@
+[
+  {
+    "type": "behavior",
+    "id": "monster_goals",
+    "strategy": "sequential_until_done",
+    "children": [ "absorb_items", "monster_special" ]
+  },
+  {
+    "type": "behavior",
+    "id": "absorb_items",
+    "strategy": "sequential",
+    "predicate": "monster_not_hallucination",
+    "children": [ "do_absorb" ]
+  },
+  {
+    "type": "behavior",
+    "id": "do_absorb",
+    "predicate": "monster_items_available",
+    "goal": "consume_items"
+  },
+  {
+    "type": "behavior",
+    "id": "monster_special",
+    "predicate": "monster_has_special",
+    "goal": "do_special"
+  }
+]

src/behavior_oracle.cpp

@@ -1,22 +1,12 @@
 #include "behavior_oracle.h"
 
-#include <array>
 #include <functional>
-#include <list>
-#include <memory>
+#include <string>
+#include <unordered_map>
 
 #include "behavior.h"
-#include "bodypart.h"
-#include "character.h"
-#include "inventory.h"
-#include "item.h"
-#include "itype.h"
-#include "player.h"
-#include "ret_val.h"
-#include "value_ptr.h"
-#include "weather.h"
-
-static const std::string flag_FIRESTARTER( "FIRESTARTER" );
+#include "character_oracle.h"
+#include "monster_oracle.h"
 
 namespace behavior
 {
@@ -26,106 +16,6 @@ status_t return_running( const oracle_t * )
     return running;
 }
 
-// To avoid a local minima when the character has access to warmth in a shelter but gets cold
-// when they go outside, this method needs to only alert when travel time to known shelter
-// approaches time to freeze.
-status_t character_oracle_t::needs_warmth_badly() const
-{
-    const player *p = dynamic_cast<const player *>( subject );
-    // Use player::temp_conv to predict whether the Character is "in trouble".
-    for( const body_part bp : all_body_parts ) {
-        if( p->temp_conv[ bp ] <= BODYTEMP_VERY_COLD ) {
-            return running;
-        }
-    }
-    return success;
-}
-
-status_t character_oracle_t::needs_water_badly() const
-{
-    // Check thirst threshold.
-    if( subject->get_thirst() > 520 ) {
-        return running;
-    }
-    return success;
-}
-
-status_t character_oracle_t::needs_food_badly() const
-{
-    // Check hunger threshold.
-    if( subject->get_hunger() >= 300 && subject->get_starvation() > 2500 ) {
-        return running;
-    }
-    return success;
-}
-
-status_t character_oracle_t::can_wear_warmer_clothes() const
-{
-    const player *p = dynamic_cast<const player *>( subject );
-    // Check inventory for wearable warmer clothes, greedily.
-    // Don't consider swapping clothes yet, just evaluate adding clothes.
-    for( const auto &i : subject->inv.const_slice() ) {
-        const item &candidate = i->front();
-        if( candidate.get_warmth() > 0 || p->can_wear( candidate ).success() ) {
-            return running;
-        }
-    }
-    return failure;
-}
-
-status_t character_oracle_t::can_make_fire() const
-{
-    // Check inventory for firemaking tools and fuel
-    bool tool = false;
-    bool fuel = false;
-    for( const auto &i : subject->inv.const_slice() ) {
-        const item &candidate = i->front();
-        if( candidate.has_flag( flag_FIRESTARTER ) ) {
-            tool = true;
-            if( fuel ) {
-                return running;
-            }
-        } else if( candidate.flammable() ) {
-            fuel = true;
-            if( tool ) {
-                return running;
-            }
-        }
-    }
-    return success;
-}
-
-status_t character_oracle_t::can_take_shelter() const
-{
-    // See if we know about some shelter
-    // Don't know how yet.
-    return failure;
-}
-
-status_t character_oracle_t::has_water() const
-{
-    // Check if we know about water somewhere
-    bool found_water = subject->inv.has_item_with( []( const item & cand ) {
-        return cand.is_food() && cand.get_comestible()->quench > 0;
-    } );
-    return found_water ? running : failure;
-}
-
-status_t character_oracle_t::has_food() const
-{
-    // Check if we know about food somewhere
-    bool found_food = subject->inv.has_item_with( []( const item & cand ) {
-        return cand.is_food() && cand.get_comestible()->has_calories();
-    } );
-    return found_food ? running : failure;
-}
-
-// predicate_map doesn't have to live here, but for the time being it's pretty pointless
-// to break it out into it's own module.
-// In principle this can be populated with any function that has a matching signature.
-// In practice each element is a pointer-to-function to one of the above methods so that
-// They can have provlidged access to the subject's internals.
-
 // Just a little helper to make populating predicate_map slightly less gross.
 static std::function < status_t( const oracle_t * ) >
 make_function( status_t ( character_oracle_t::* fun )() const )
@@ -141,7 +31,11 @@ std::unordered_map<std::string, std::function<status_t( const oracle_t * )>> pre
         { "npc_can_make_fire", make_function( &character_oracle_t::can_make_fire ) },
         { "npc_can_take_shelter", make_function( &character_oracle_t::can_take_shelter ) },
         { "npc_has_water", make_function( &character_oracle_t::has_water ) },
-        { "npc_has_food", make_function( &character_oracle_t::has_food ) }
+        { "npc_has_food", make_function( &character_oracle_t::has_food ) },
+        { "monster_has_special", static_cast<status_t ( oracle_t::* )() const>( &monster_oracle_t::has_special ) },
+        { "monster_not_hallucination", static_cast<status_t ( oracle_t::* )() const>( &monster_oracle_t::not_hallucination ) },
+        { "monster_items_available", static_cast<status_t ( oracle_t::* )() const>( &monster_oracle_t::items_available ) }
     }
 };
+
 } // namespace behavior

src/behavior_oracle.h

@@ -6,8 +6,6 @@
 #include <string>
 #include <unordered_map>
 
-class Character;
-
 namespace behavior
 {
 enum status_t : char;
@@ -25,27 +23,6 @@ class oracle_t
 
 status_t return_running( const oracle_t * );
 
-class character_oracle_t : public oracle_t
-{
-    public:
-        character_oracle_t( const Character *subject ) {
-            this->subject = subject;
-        }
-        /**
-         * Predicates used by AI to determine goals.
-         */
-        status_t needs_warmth_badly() const;
-        status_t needs_water_badly() const;
-        status_t needs_food_badly() const;
-        status_t can_wear_warmer_clothes() const;
-        status_t can_make_fire() const;
-        status_t can_take_shelter() const;
-        status_t has_water() const;
-        status_t has_food() const;
-    private:
-        const Character *subject;
-};
-
 extern std::unordered_map<std::string, std::function<status_t( const oracle_t * )>> predicate_map;
 
 } // namespace behavior

src/character_oracle.cpp

@@ -0,0 +1,116 @@
+#include <array>
+#include <list>
+#include <memory>
+
+#include "behavior.h"
+#include "character_oracle.h"
+#include "bodypart.h"
+#include "character.h"
+#include "inventory.h"
+#include "item.h"
+#include "itype.h"
+#include "player.h"
+#include "ret_val.h"
+#include "value_ptr.h"
+#include "weather.h"
+
+static const std::string flag_FIRESTARTER( "FIRESTARTER" );
+
+namespace behavior
+{
+
+// To avoid a local minima when the character has access to warmth in a shelter but gets cold
+// when they go outside, this method needs to only alert when travel time to known shelter
+// approaches time to freeze.
+status_t character_oracle_t::needs_warmth_badly() const
+{
+    const player *p = dynamic_cast<const player *>( subject );
+    // Use player::temp_conv to predict whether the Character is "in trouble".
+    for( const body_part bp : all_body_parts ) {
+        if( p->temp_conv[ bp ] <= BODYTEMP_VERY_COLD ) {
+            return running;
+        }
+    }
+    return success;
+}
+
+status_t character_oracle_t::needs_water_badly() const
+{
+    // Check thirst threshold.
+    if( subject->get_thirst() > 520 ) {
+        return running;
+    }
+    return success;
+}
+
+status_t character_oracle_t::needs_food_badly() const
+{
+    // Check hunger threshold.
+    if( subject->get_hunger() >= 300 && subject->get_starvation() > 2500 ) {
+        return running;
+    }
+    return success;
+}
+
+status_t character_oracle_t::can_wear_warmer_clothes() const
+{
+    const player *p = dynamic_cast<const player *>( subject );
+    // Check inventory for wearable warmer clothes, greedily.
+    // Don't consider swapping clothes yet, just evaluate adding clothes.
+    for( const auto &i : subject->inv.const_slice() ) {
+        const item &candidate = i->front();
+        if( candidate.get_warmth() > 0 || p->can_wear( candidate ).success() ) {
+            return running;
+        }
+    }
+    return failure;
+}
+
+status_t character_oracle_t::can_make_fire() const
+{
+    // Check inventory for firemaking tools and fuel
+    bool tool = false;
+    bool fuel = false;
+    for( const auto &i : subject->inv.const_slice() ) {
+        const item &candidate = i->front();
+        if( candidate.has_flag( flag_FIRESTARTER ) ) {
+            tool = true;
+            if( fuel ) {
+                return running;
+            }
+        } else if( candidate.flammable() ) {
+            fuel = true;
+            if( tool ) {
+                return running;
+            }
+        }
+    }
+    return success;
+}
+
+status_t character_oracle_t::can_take_shelter() const
+{
+    // See if we know about some shelter
+    // Don't know how yet.
+    return failure;
+}
+
+status_t character_oracle_t::has_water() const
+{
+    // Check if we know about water somewhere
+    bool found_water = subject->inv.has_item_with( []( const item & cand ) {
+        return cand.is_food() && cand.get_comestible()->quench > 0;
+    } );
+    return found_water ? running : failure;
+}
+
+status_t character_oracle_t::has_food() const
+{
+    // Check if we know about food somewhere
+    bool found_food = subject->inv.has_item_with( []( const item & cand ) {
+        return cand.is_food() && cand.get_comestible()->has_calories();
+    } );
+    return found_food ? running : failure;
+}
+
+} // namespace behavior

src/character_oracle.h

@@ -0,0 +1,34 @@
+#pragma once
+#ifndef CATA_SRC_CHARACTER_ORACLE_H
+#define CATA_SRC_CHARACTER_ORACLE_H
+
+#include "behavior_oracle.h"
+
+class Character;
+
+namespace behavior
+{
+
+class character_oracle_t : public oracle_t
+{
+    public:
+        character_oracle_t( const Character *subject ) {
+            this->subject = subject;
+        }
+        /**
+         * Predicates used by AI to determine goals.
+         */
+        status_t needs_warmth_badly() const;
+        status_t needs_water_badly() const;
+        status_t needs_food_badly() const;
+        status_t can_wear_warmer_clothes() const;
+        status_t can_make_fire() const;
+        status_t can_take_shelter() const;
+        status_t has_water() const;
+        status_t has_food() const;
+    private:
+        const Character *subject;
+};
+
+} //namespace behavior
+#endif // CATA_SRC_CHARACTER_ORACLE_H

src/monmove.cpp

@@ -13,6 +13,7 @@
 #include <unordered_map>
 
 #include "avatar.h"
+#include "behavior.h"
 #include "bionics.h"
 #include "cata_utility.h"
 #include "creature_tracker.h"
@@ -30,6 +31,7 @@
 #include "memory_fast.h"
 #include "messages.h"
 #include "monfaction.h"
+#include "monster_oracle.h"
 #include "mtype.h"
 #include "npc.h"
 #include "pathfinding.h"
@@ -629,10 +631,14 @@ void monster::move()
         return;
     }
 
+    behavior::monster_oracle_t oracle( this );
+    behavior::tree goals;
+    goals.add( type->get_goals() );
+    std::string action = goals.tick( &oracle );
     //The monster can consume objects it stands on. Check if there are any.
     //If there are. Consume them.
-    if( !is_hallucination() && ( has_flag( MF_ABSORBS ) || has_flag( MF_ABSORBS_SPLITS ) ) &&
-        !g->m.has_flag( TFLAG_SEALED, pos() ) && g->m.has_items( pos() ) ) {
+    // TODO: Stick this in a map and dispatch to it via the action string.
+    if( action == "consume_items" ) {
         if( g->u.sees( *this ) ) {
             add_msg( _( "The %s flows around the objects on the floor and they are quickly dissolved!" ),
                      name() );