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 @@ class EngineWrap final {
    }
 };
 
+// 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 @@ class Game final : public Singleton <Game> {
       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);

inc/yapb.h

@@ -355,6 +355,8 @@ class Bot final {
    Array <edict_t *> m_ignoredBreakable {}; // list of ignored breakables
    Array <edict_t *> m_hostages {}; // pointer to used hostage entities
 
+   UniquePtr <class PlayerHitboxEnumerator> m_hitboxEnumerator {};
+
    Path *m_path {}; // pointer to the current path node
    String m_chatBuffer {}; // space for strings (say text...)
    Frustum::Planes m_viewFrustum {};
@@ -407,6 +409,8 @@ class Bot final {
    bool isWeaponRestrictedAMX (int wid);
    bool isInViewCone (const Vector &origin);
    bool checkBodyParts (edict_t *target);
+   bool checkBodyPartsWithOffsets (edict_t *target);
+   bool checkBodyPartsWithHitboxes (edict_t *target);
    bool seesEnemy (edict_t *player);
    bool hasActiveGoal ();
    bool advanceMovement ();

src/combat.cpp

@@ -13,6 +13,7 @@ ConVar cv_check_enemy_rendering ("check_enemy_rendering", "0", "Enables or disab
 ConVar cv_check_enemy_invincibility ("check_enemy_invincibility", "0", "Enables or disables checking enemy invincibility. Useful for some mods.");
 ConVar cv_stab_close_enemies ("stab_close_enemies", "1", "Enables or disables bot ability to stab the enemy with knife if bot is in good condition.");
 ConVar cv_use_engine_pvs_check ("use_engine_pvs_check", "0", "Use engine to check potential visibility of an enemy.");
+ConVar cv_use_hitbox_enemy_targeting ("use_hitbox_enemy_targeting", "0", "Use hitbox-based enemy targeting, instead of offset based. Use with the yb_use_engine_pvs_check enabled to reduce CPU usage.");
 
 ConVar mp_friendlyfire ("mp_friendlyfire", nullptr, Var::GameRef);
 ConVar sv_gravity ("sv_gravity", nullptr, Var::GameRef);
@@ -137,6 +138,14 @@ bool Bot::checkBodyParts (edict_t *target) {
       return false;
    }
 
+   // hitboxes requested ?
+   if (game.is (GameFlags::HasStudioModels) && cv_use_hitbox_enemy_targeting) {
+      return checkBodyPartsWithHitboxes (target);
+   }
+   return checkBodyPartsWithOffsets (target);
+}
+
+bool Bot::checkBodyPartsWithOffsets (edict_t *target) {
    TraceResult result {};
    const auto &eyes = getEyesPos ();
 
@@ -215,6 +224,77 @@ bool Bot::checkBodyParts (edict_t *target) {
    return false;
 }
 
+bool Bot::checkBodyPartsWithHitboxes (edict_t *target) {
+   const auto self = pev->pContainingEntity;
+   const auto refersh = m_frameInterval * 1.5f;
+
+   TraceResult result {};
+   const auto &eyes = getEyesPos ();
+
+   const auto hitsTarget = [&] () -> bool {
+      return result.flFraction >= 1.0f || result.pHit == target;
+   };
+
+   // creatures can't hurt behind anything
+   const auto ignoreFlags = m_isCreature ? TraceIgnore::None : TraceIgnore::Everything;
+
+   // get the stomach hitbox
+   m_enemyParts = Visibility::None;
+   game.testLine (eyes, m_hitboxEnumerator->get (target, PlayerPart::Stomach, refersh), ignoreFlags, self, &result);
+
+   if (hitsTarget ()) {
+      m_enemyParts |= Visibility::Body;
+      m_enemyOrigin = result.vecEndPos;
+   }
+
+   // get the stomach hitbox
+   m_enemyParts = Visibility::None;
+   game.testLine (eyes, m_hitboxEnumerator->get (target, PlayerPart::Head, refersh), ignoreFlags, self, &result);
+
+   if (hitsTarget ()) {
+      m_enemyParts |= Visibility::Head;
+      m_enemyOrigin = result.vecEndPos;
+   }
+
+   if (m_enemyParts != Visibility::None) {
+      return true;
+   }
+
+   // get the left hitbox
+   m_enemyParts = Visibility::None;
+   game.testLine (eyes, m_hitboxEnumerator->get (target, PlayerPart::LeftArm, refersh), ignoreFlags, self, &result);
+
+   if (hitsTarget ()) {
+      m_enemyParts |= Visibility::Other;
+      m_enemyOrigin = result.vecEndPos;
+
+      return true;
+   }
+
+   // get the right hitbox
+   m_enemyParts = Visibility::None;
+   game.testLine (eyes, m_hitboxEnumerator->get (target, PlayerPart::RightArm, refersh), ignoreFlags, self, &result);
+
+   if (hitsTarget ()) {
+      m_enemyParts |= Visibility::Other;
+      m_enemyOrigin = result.vecEndPos;
+
+      return true;
+   }
+
+   // get the feet spot
+   m_enemyParts = Visibility::None;
+   game.testLine (eyes, m_hitboxEnumerator->get (target, PlayerPart::Feet, refersh), ignoreFlags, self, &result);
+
+   if (hitsTarget ()) {
+      m_enemyParts |= Visibility::Other;
+      m_enemyOrigin = result.vecEndPos;
+
+      return true;
+   }
+   return false;
+}
+
 bool Bot::seesEnemy (edict_t *player) {
    auto isBehindSmokeClouds = [&] (const Vector &pos) {
       if (cv_smoke_grenade_checks.as <int> () == 2) {

src/engine.cpp

@@ -835,6 +835,11 @@ bool Game::loadCSBinary () {
             m_gameFlags &= ~GameFlags::Modern;
          }
 
+         // allow to enable hitbox-based aiming on fresh games
+         if (is (GameFlags::Modern)) {
+            m_gameFlags |= GameFlags::HasStudioModels;
+         }
+
          if (is (GameFlags::Metamod)) {
             return false;
          }
@@ -1404,3 +1409,131 @@ float LightMeasure::getLightLevel (const Vector &point) {
 float LightMeasure::getSkyColor () {
    return static_cast <float> (Color (sv_skycolor_r.as <int> (), sv_skycolor_g.as <int> (), sv_skycolor_b.as <int> ()).avg ());
 }
+
+Vector PlayerHitboxEnumerator::get (edict_t *ent, int part, float updateTimestamp) {
+   auto parts = &m_parts[game.indexOfEntity (ent) % kGameMaxPlayers];
+
+   if (game.time () > updateTimestamp) {
+      update (ent);
+      parts->updated = game.time () + updateTimestamp;
+   }
+
+   switch (part) {
+   default:
+   case PlayerPart::Head:
+      return parts->head;
+
+   case PlayerPart::Stomach:
+      return parts->stomach;
+
+   case PlayerPart::LeftArm:
+      return parts->left;
+
+   case PlayerPart::RightArm:
+      return parts->right;
+
+   case PlayerPart::Feet:
+      return parts->feet;
+
+   case PlayerPart::RightLeg:
+      return { parts->right.x, parts->right.y, parts->feet.z };
+
+   case PlayerPart::LeftLeg:
+      return { parts->left.x, parts->left.y, parts->feet.z };
+   }
+}
+
+void PlayerHitboxEnumerator::update (edict_t *ent) {
+   constexpr auto kInvalidHitbox = -1;
+
+   if (!util.isAlive (ent)) {
+      return;
+   }
+   // get info about player
+   auto parts = &m_parts[game.indexOfEntity (ent) % kGameMaxPlayers];
+
+   // set the feet without bones
+   parts->feet = ent->v.origin;
+
+   constexpr auto kStandFeet = 34.0f;
+   constexpr auto kCrouchFeet = 14.0f;
+
+   // legs position isn't calculated to reduce cpu usage, just use some universal feet spot
+   if (ent->v.flags & FL_DUCKING) {
+      parts->feet.z = ent->v.origin.z - kCrouchFeet;
+   }
+   else {
+      parts->feet.z = ent->v.origin.z - kStandFeet;
+   }
+
+   auto getHitbox = [&kInvalidHitbox] (studiohdr_t *hdr, mstudiobbox_t *bb, int part) {
+      int hitbox = kInvalidHitbox;
+
+      for (auto i = 0; i < hdr->numhitboxes; ++i) {
+         const auto set = &bb[i];
+
+         if (set->group != part) {
+            continue;
+         }
+         hitbox = i;
+         break;
+      }
+      return hitbox;
+   };
+   auto model = engfuncs.pfnGetModelPtr (ent);
+   auto studiohdr = reinterpret_cast <studiohdr_t *> (model);
+
+   // this can be null ?
+   if (model && studiohdr) {
+      auto bboxset = reinterpret_cast <mstudiobbox_t *> (reinterpret_cast <uint8_t *> (studiohdr) + studiohdr->hitboxindex);
+
+      // get the head
+      auto hitbox = getHitbox (studiohdr, bboxset, PlayerPart::Head);
+
+      if (hitbox != kInvalidHitbox) {
+         engfuncs.pfnGetBonePosition (ent, bboxset[hitbox].bone, parts->head, nullptr);
+
+         parts->head.z += bboxset[hitbox].bbmax.z;
+         parts->head = { ent->v.origin.x, ent->v.origin.y, parts->head.z };
+      }
+      hitbox = kInvalidHitbox;
+
+      // get the body (stomach)
+      hitbox = getHitbox (studiohdr, bboxset, PlayerPart::Stomach);
+
+      if (hitbox != kInfiniteDistance) {
+         engfuncs.pfnGetBonePosition (ent, bboxset[hitbox].bone, parts->stomach, nullptr);
+      }
+      hitbox = kInvalidHitbox;
+
+      // get the left (arm)
+      hitbox = getHitbox (studiohdr, bboxset, PlayerPart::LeftArm);
+
+      if (hitbox != kInfiniteDistance) {
+         engfuncs.pfnGetBonePosition (ent, bboxset[hitbox].bone, parts->left, nullptr);
+      }
+
+      // get the right (arm)
+      hitbox = getHitbox (studiohdr, bboxset, PlayerPart::RightArm);
+
+      if (hitbox != kInfiniteDistance) {
+         engfuncs.pfnGetBonePosition (ent, bboxset[hitbox].bone, parts->right, nullptr);
+      }
+      return;
+   }
+   else {
+      game.clearGameFlag (GameFlags::HasStudioModels); // yes, only a single fail will disable this
+   }
+
+   parts->head = ent->v.origin + ent->v.view_ofs;
+   parts->stomach = ent->v.origin;
+
+   parts->left = parts->head;
+   parts->right = parts->head;
+}
+
+void PlayerHitboxEnumerator::reset () {
+   for (auto &part : m_parts) {
+      part = {};
+   }
+}

src/manager.cpp

@@ -1229,6 +1229,9 @@ Bot::Bot (edict_t *bot, int difficulty, int personality, int team, int skin) {
    // init async planner
    m_planner = cr::makeUnique <AStarAlgo> (graph.length ());
 
+   // init player models parts enumerator
+   m_hitboxEnumerator = cr::makeUnique <PlayerHitboxEnumerator> ();
+
    // bot is not kicked by rotation
    m_kickedByRotation = false;
 
@@ -1241,7 +1244,6 @@ Bot::Bot (edict_t *bot, int difficulty, int personality, int team, int skin) {
    newRound ();
 }
 
-
 void Bot::clearAmmoInfo () {
    plat.bzero (&m_ammoInClip, sizeof (m_ammoInClip));
    plat.bzero (&m_ammo, sizeof (m_ammo));
@@ -1545,6 +1547,7 @@ void Bot::newRound () {
    m_followWaitTime = 0.0f;
 
    m_hostages.clear ();
+   m_hitboxEnumerator->reset ();
 
    m_approachingLadderTimer.invalidate ();
    m_forgetLastVictimTimer.invalidate ();