Bots skip weapons they cannot reach when scavenging

src/game/server/neo/bot/behavior/neo_bot_seek_weapon.cpp

@@ -9,6 +9,42 @@
 static constexpr int BOT_WEP_PREF_RANK_UNPREFERRED = -1;
 static constexpr int BOT_WEP_PREF_RANK_EMPTY = -2;
 
+// A weapon lies on a nav area when it is over the area, or at most half a player's width past its edge
+// (nav_generate areas often stop short of wall boundaries),
+static constexpr float BOT_WEP_MAX_OUTSIDE_AREA = HalfHumanWidth;
+// and at most this far above the area's surface (such as a desk or crate surface)
+static constexpr float BOT_WEP_MAX_HEIGHT_ABOVE_AREA = 32.0f;
+// or this far below it (a nav area's plane is rarely an exact flush fit with a stairway's steps)
+static constexpr float BOT_WEP_MAX_DEPTH_BELOW_AREA = 8.0f;
+static constexpr float BOT_WEP_AREA_SEARCH_RANGE = 64.0f;
+
+//---------------------------------------------------------------------------------------------
+// Weapons can come to rest where no nav area exists: in a pit, behind a counter, out of a window
+static CNavArea *GetWeaponNavArea( CBaseEntity *pWeapon )
+{
+	const Vector vecWeapon = pWeapon->WorldSpaceCenter();
+	CNavArea *pArea = TheNavMesh->GetNearestNavArea( vecWeapon, false, BOT_WEP_AREA_SEARCH_RANGE, true, false );
+	if ( !pArea )
+	{
+		return nullptr;
+	}
+
+	Vector vecClosest;
+	pArea->GetClosestPointOnArea( vecWeapon, &vecClosest );
+	if ( ( vecWeapon - vecClosest ).Length2D() > BOT_WEP_MAX_OUTSIDE_AREA )
+	{
+		return nullptr;
+	}
+
+	const float flHeightAboveArea = vecWeapon.z - vecClosest.z;
+	if ( flHeightAboveArea > BOT_WEP_MAX_HEIGHT_ABOVE_AREA || flHeightAboveArea < -BOT_WEP_MAX_DEPTH_BELOW_AREA )
+	{
+		return nullptr;
+	}
+
+	return pArea;
+}
+
 //---------------------------------------------------------------------------------------------
 bool IsUndroppablePrimary( CBaseCombatWeapon *pPrimary )
 {
@@ -174,14 +210,17 @@ CBaseEntity *FindNearestPrimaryWeapon( const CNEOBot *me, bool bAllowDropGhost,
 
 			if ( bBetterFound )
 			{
+				// A path to an off-mesh weapon ends with a straight walk to it, over whatever lies between
+				CNavArea *pWepArea = GetWeaponNavArea( pEntity );
+				if ( !pWepArea )
+				{
+					continue;
+				}
+
 				// Check if weapon candidate is in PVS of me
-				if ( pMyArea )
+				if ( pMyArea && !pMyArea->IsPotentiallyVisible( pWepArea ) )
 				{
-					CNavArea *pWepArea = TheNavMesh->GetNavArea( pEntity->WorldSpaceCenter() );
-					if ( pWepArea && !pMyArea->IsPotentiallyVisible( pWepArea ) )
-					{
-						continue;
-					}
+					continue;
 				}
 
 				flClosestDistSq = flDistSq;
@@ -201,6 +240,36 @@ CNEOBotSeekWeapon::CNEOBotSeekWeapon( CBaseEntity *pTargetWeapon, CNEOIgnoredWea
 	m_pIgnoredWeapons = pIgnoredWeapons;
 }
 
+//---------------------------------------------------------------------------------------------
+// Remember a weapon the bot failed to reach, so the next scavenge does not pick it again
+void CNEOBotSeekWeapon::IgnoreTargetWeapon( void )
+{
+	if ( !m_hTargetWeapon || !m_pIgnoredWeapons || m_pIgnoredWeapons->Has( m_hTargetWeapon ) )
+	{
+		return;
+	}
+
+	m_pIgnoredWeapons->Add( m_hTargetWeapon );
+}
+
+//---------------------------------------------------------------------------------------------
+// Only a full path to the weapon's nav area: a partial one ends with a straight walk from the edge of the mesh
+bool CNEOBotSeekWeapon::PathToTargetWeapon( CNEOBot *me )
+{
+	// The weapon may have been knocked off the mesh since it was chosen
+	const CNavArea *pWepArea = GetWeaponNavArea( m_hTargetWeapon );
+	if ( !pWepArea )
+	{
+		m_path.Invalidate();
+		return false;
+	}
+
+	// Stay on the area: from its edge a bot still touches a weapon lying against the wall beyond it
+	Vector vecGoal;
+	pWepArea->GetClosestPointOnArea( m_hTargetWeapon->WorldSpaceCenter(), &vecGoal );
+	return CNEOBotPathCompute( me, m_path, vecGoal, FASTEST_ROUTE, PATH_NO_LENGTH_LIMIT, PATH_TRUNCATE_INCOMPLETE_PATH );
+}
+
 //---------------------------------------------------------------------------------------------
 CBaseEntity *CNEOBotSeekWeapon::FindAndPathToWeapon( CNEOBot *me )
 {
@@ -209,19 +278,16 @@ CBaseEntity *CNEOBotSeekWeapon::FindAndPathToWeapon( CNEOBot *me )
 		m_hTargetWeapon = FindNearestPrimaryWeapon( me, false, m_pIgnoredWeapons );
 	}
 
-	if ( m_hTargetWeapon )
-	{
-		if ( !CNEOBotPathCompute( me, m_path, m_hTargetWeapon->GetAbsOrigin(), FASTEST_ROUTE ) || !m_path.IsValid() )
-		{
-			m_hTargetWeapon = nullptr;
-			m_path.Invalidate();
-		}
-	}
-	else
+	if ( !m_hTargetWeapon )
 	{
 		// no weapon found
 		m_path.Invalidate();
 	}
+	else if ( !PathToTargetWeapon( me ) )
+	{
+		IgnoreTargetWeapon();
+		m_hTargetWeapon = nullptr;
+	}
 
 	return m_hTargetWeapon;
 }
@@ -250,6 +316,14 @@ ActionResult< CNEOBot >	CNEOBotSeekWeapon::OnStart( CNEOBot *me, Action< CNEOBot
 		return Done("No valid replacement primary found");
 	}
 
+	// Check the path before a ghost carrier drops the ghost for this weapon
+	if ( !PathToTargetWeapon( me ) )
+	{
+		IgnoreTargetWeapon();
+		return Done( "No full path to the weapon" );
+	}
+	m_repathTimer.Start( RandomFloat( 1.0f, 2.0f ) );
+
 	auto *pNeoPrimary = assert_cast<CNEOBaseCombatWeapon *>( pPrimary );
 	if ( pNeoPrimary && ( pNeoPrimary->GetNeoWepBits() & NEO_WEP_GHOST ) )
 	{
@@ -271,14 +345,16 @@ ActionResult< CNEOBot >	CNEOBotSeekWeapon::Update( CNEOBot *me, float interval )
 
 	if ( m_giveUpTimer.IsElapsed() )
 	{
+		IgnoreTargetWeapon();
 		return Done("Gave up seeking weapon");
 	}
 
 	if ( !m_repathTimer.HasStarted() || m_repathTimer.IsElapsed() )
 	{
-		if ( !CNEOBotPathCompute( me, m_path, m_hTargetWeapon->GetAbsOrigin(), FASTEST_ROUTE ) )
+		if ( !PathToTargetWeapon( me ) )
 		{
-			return Done("Unable to find a path to the nearest primary weapon");
+			IgnoreTargetWeapon();
+			return Done( "No full path to the weapon" );
 		}
 		m_repathTimer.Start( RandomFloat( 1.0f, 2.0f ) );
 	}
@@ -292,10 +368,7 @@ ActionResult< CNEOBot >	CNEOBotSeekWeapon::Update( CNEOBot *me, float interval )
 	const float flMaxEndpointDistSqr = 150.0f * 150.0f;
 	if ( m_path.GetEndPosition().DistToSqr( m_hTargetWeapon->GetAbsOrigin() ) > flMaxEndpointDistSqr )
 	{
-		if ( m_pIgnoredWeapons && !m_pIgnoredWeapons->Has( m_hTargetWeapon ) )
-		{
-			m_pIgnoredWeapons->Add( m_hTargetWeapon );
-		}
+		IgnoreTargetWeapon();
 		return Done("Weapon is unreachable (path doesn't get close enough)");
 	}
 
@@ -354,6 +427,7 @@ ActionResult< CNEOBot > CNEOBotSeekWeapon::OnResume( CNEOBot *me, Action< CNEOBo
 //---------------------------------------------------------------------------------------------
 EventDesiredResult< CNEOBot > CNEOBotSeekWeapon::OnStuck( CNEOBot *me )
 {
+	IgnoreTargetWeapon();
 	m_hTargetWeapon = nullptr;
 	m_repathTimer.Invalidate();
 	FindAndPathToWeapon(me);
@@ -369,6 +443,7 @@ EventDesiredResult< CNEOBot > CNEOBotSeekWeapon::OnMoveToSuccess( CNEOBot *me, c
 //---------------------------------------------------------------------------------------------
 EventDesiredResult< CNEOBot > CNEOBotSeekWeapon::OnMoveToFailure( CNEOBot *me, const Path *path, MoveToFailureType reason )
 {
+	IgnoreTargetWeapon();
 	m_hTargetWeapon = nullptr;
 	m_repathTimer.Invalidate();
 	FindAndPathToWeapon(me);

src/game/server/neo/bot/behavior/neo_bot_seek_weapon.h

@@ -46,5 +46,7 @@ class CNEOBotSeekWeapon : public Action< CNEOBot >
 	CountdownTimer m_repathTimer;
 	CountdownTimer m_giveUpTimer;
 
+	bool PathToTargetWeapon( CNEOBot *me );
 	CBaseEntity *FindAndPathToWeapon( CNEOBot *me );
+	void IgnoreTargetWeapon( void );
 };

src/game/server/neo/bot/neo_bot_path_compute.cpp

@@ -34,6 +34,12 @@ static void CNEOBotReservePath(CNEOBot* me, PathFollower& path)
 	}
 }
 
+// A path that stops short of the goal is only wanted if the caller asked for partial paths
+static bool IsPathUsable(const PathFollower& path, bool reachedGoal, bool includeGoalIfPathFails)
+{
+	return path.IsValid() && (reachedGoal || includeGoalIfPathFails);
+}
+
 // By default, assumes that we would prefer to have partial paths even if we can't make a full path
 // to accomodate scenarios like getting as close as possible to a hazard area but not into it
 // Set includeGoalIfPathFails to false if you need to get the full path (or nothing on failure)
@@ -42,22 +48,24 @@ bool CNEOBotPathCompute(CNEOBot* bot, PathFollower& path, const Vector& goal, Ro
 	Assert(goal.IsValid());
 
 	CNEOBotPathCost cost_with_reservations(bot, route);
-	path.Compute(bot, goal, cost_with_reservations, maxPathLength, includeGoalIfPathFails, requireGoalArea);
-	if (path.IsValid())
+	bool reachedGoal = path.Compute(bot, goal, cost_with_reservations, maxPathLength, includeGoalIfPathFails, requireGoalArea);
+	if (IsPathUsable(path, reachedGoal, includeGoalIfPathFails))
 	{
 		CNEOBotReservePath(bot, path);
 		return true;
 	}
 
 	CNEOBotPathCost cost_without_reservations(bot, FASTEST_ROUTE);
 	cost_without_reservations.m_bIgnoreReservations = true;
-	path.Compute(bot, goal, cost_without_reservations, maxPathLength, includeGoalIfPathFails, requireGoalArea);
-	if (path.IsValid())
+	reachedGoal = path.Compute(bot, goal, cost_without_reservations, maxPathLength, includeGoalIfPathFails, requireGoalArea);
+	if (IsPathUsable(path, reachedGoal, includeGoalIfPathFails))
 	{
 		CNEOBotReservePath(bot, path);
 		return true;
 	}
 
+	// Path::Compute leaves a partial path valid even when told not to append the goal
+	path.Invalidate();
 	return false;
 }