Hold an empty weapon on its empty idle

src/game/shared/neo/weapons/weapon_neobasecombatweapon.cpp

@@ -941,6 +941,22 @@ void CNEOBaseCombatWeapon::DryFire()
 	m_flNextPrimaryAttack = gpGlobals->curtime + GetFastestDryRefireTime(); // SequenceDuration();
 }
 
+// An empty weapon idles on its empty sequence where the model has one, such as a pistol with its slide held back
+bool CNEOBaseCombatWeapon::SendWeaponAnim(int iActivity)
+{
+	if (iActivity == ACT_VM_IDLE && UsesClipsForAmmo1() && m_iClip1 <= 0 && HasEmptyIdle())
+	{
+		iActivity = ACT_VM_IDLE_EMPTY;
+	}
+
+	return BaseClass::SendWeaponAnim(iActivity);
+}
+
+bool CNEOBaseCombatWeapon::HasEmptyIdle()
+{
+	return SelectWeightedSequence(ACT_VM_IDLE_EMPTY) != ACTIVITY_NOT_AVAILABLE;
+}
+
 void CNEOBaseCombatWeapon::PrimaryAttack(void)
 {
 	if (ShootingIsPrevented())
@@ -1064,6 +1080,12 @@ void CNEOBaseCombatWeapon::PrimaryAttack(void)
 		m_iPrimaryAmmoCount -= info.m_iShots;
 	}
 
+	// the last round's shot goes straight on to the empty idle when it ends
+	if (UsesClipsForAmmo1() && m_iClip1 <= 0 && HasEmptyIdle())
+	{
+		SetWeaponIdleTime(gpGlobals->curtime + SequenceDuration());
+	}
+
 	info.m_flDistance = MAX_TRACE_LENGTH;
 	info.m_iAmmoType = m_iPrimaryAmmoType;
 	info.m_iTracerFreq = UsesTracers() ? 1 : 0;

src/game/shared/neo/weapons/weapon_neobasecombatweapon.h

@@ -191,6 +191,7 @@ class CNEOBaseCombatWeapon : public CBaseHL2MPCombatWeapon
 #endif
 
 	virtual void DryFire(void);
+	virtual bool SendWeaponAnim(int iActivity) override;
 
 	virtual Activity GetPrimaryAttackActivity(void) override;
 #ifdef CLIENT_DLL
@@ -292,6 +293,7 @@ class CNEOBaseCombatWeapon : public CBaseHL2MPCombatWeapon
 
 private:
 	CNEOBaseCombatWeapon(const CNEOBaseCombatWeapon &other);
+	bool HasEmptyIdle();
 
 };