aim: added optional hitbox-based aiming for bots (ref #579)

inc/engine.h

@@ -48,7 +48,8 @@ CR_DECLARE_SCOPED_ENUM (GameFlags,
    HasBotVoice = cr::bit (11), // on that game version we can use chatter
    AnniversaryHL25 = cr::bit (12), // half-life 25th anniversary engine
    Xash3DLegacy = cr::bit (13), // old xash3d-branch
-   ZombieMod = cr::bit (14) // zombie mod is active
+   ZombieMod = cr::bit (14), // zombie mod is active
+   HasStudioModels = cr::bit (15) // game supports studio models, so we can use hitbox-based aiming
 )
 
 // defines map type
@@ -70,6 +71,18 @@ CR_DECLARE_SCOPED_ENUM (EntitySearchResult,
    Break
 )
 
+// player body parts
+CR_DECLARE_SCOPED_ENUM (PlayerPart,
+   Head = 1,
+   Chest,
+   Stomach,
+   LeftArm,
+   RightArm,
+   LeftLeg,
+   RightLeg,
+   Feet // custom!
+)
+
 // variable reg pair
 struct ConVarReg {
    cvar_t reg;
@@ -112,6 +125,29 @@ public:
    }
 };
 
+// player model part info enumerator
+class PlayerHitboxEnumerator final {
+public:
+   struct Info {
+      float updated {};
+      Vector head {};
+      Vector stomach {};
+      Vector feet {};
+      Vector right {};
+      Vector left {};
+   } m_parts[kGameMaxPlayers] {};
+
+public:
+   // get's the enemy part based on bone info
+   Vector get (edict_t *ent, int part, float updateTimestamp);
+
+   // update bones positions for given player
+   void update (edict_t *ent);
+
+   // reset all the poisitons
+   void reset ();
+};
+
 // provides utility functions to not call original engine (less call-cost)
 class Game final : public Singleton <Game> {
 public:
@@ -353,6 +389,11 @@ public:
       m_gameFlags |= type;
    }
 
+   // clears game flag
+   void clearGameFlag (const int type) {
+      m_gameFlags &= ~type;
+   }
+
    // gets the map type
    bool mapIs (const int type) const {
       return !!(m_mapFlags & type);