From 387624e1580d4345dcbd3a3ae3a695de94bdd377 Mon Sep 17 00:00:00 2001
From: scrawl <scrawl@baseoftrash.de>
Date: Sat, 26 Sep 2015 01:55:12 +0200
Subject: [PATCH] Add a threshold to AiFollow distance

Idle animations can move the actor around slightly, which sometimes causes AiFollow to constantly toggle between "arrived" and "following" state even when the player isn't moving. Could be observed by summoning a bonelord.
---
 apps/openmw/mwmechanics/aifollow.cpp | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/apps/openmw/mwmechanics/aifollow.cpp b/apps/openmw/mwmechanics/aifollow.cpp
index cd67c6058..d9356da93 100644
--- a/apps/openmw/mwmechanics/aifollow.cpp
+++ b/apps/openmw/mwmechanics/aifollow.cpp
@@ -20,8 +20,9 @@ namespace MWMechanics
 struct AiFollowStorage : AiTemporaryBase
 {
     float mTimer;
+    bool mMoving;
 
-    AiFollowStorage() : mTimer(0.f) {}
+    AiFollowStorage() : mTimer(0.f), mMoving(false) {}
 };
 
 int AiFollow::mFollowIndexCounter = 0;
@@ -64,10 +65,11 @@ bool AiFollow::execute (const MWWorld::Ptr& actor, CharacterController& characte
 
     actor.getClass().getCreatureStats(actor).setDrawState(DrawState_Nothing);
 
+    AiFollowStorage& storage = state.get<AiFollowStorage>();
+
     // AiFollow requires the target to be in range and within sight for the initial activation
     if (!mActive)
     {
-        AiFollowStorage& storage = state.get<AiFollowStorage>();
         storage.mTimer -= duration;
 
         if (storage.mTimer < 0)
@@ -126,7 +128,15 @@ bool AiFollow::execute (const MWWorld::Ptr& actor, CharacterController& characte
     //Set the target destination from the actor
     ESM::Pathgrid::Point dest = target.getRefData().getPosition().pos;
 
-    if(distance(dest, pos.pos[0], pos.pos[1], pos.pos[2]) < followDistance) //Stop when you get close
+    float dist = distance(dest, pos.pos[0], pos.pos[1], pos.pos[2]);
+    const float threshold = 10;
+
+    if (storage.mMoving)  //Stop when you get close
+        storage.mMoving = (dist > followDistance);
+    else
+        storage.mMoving = (dist > followDistance + threshold);
+
+    if(!storage.mMoving)
     {
         actor.getClass().getMovementSettings(actor).mPosition[1] = 0;
 
@@ -141,9 +151,9 @@ bool AiFollow::execute (const MWWorld::Ptr& actor, CharacterController& characte
     }
 
     //Check if you're far away
-    if(distance(dest, pos.pos[0], pos.pos[1], pos.pos[2]) > 450)
+    if(dist > 450)
         actor.getClass().getCreatureStats(actor).setMovementFlag(MWMechanics::CreatureStats::Flag_Run, true); //Make NPC run
-    else if(distance(dest, pos.pos[0], pos.pos[1], pos.pos[2])  < 325) //Have a bit of a dead zone, otherwise npc will constantly flip between running and not when right on the edge of the running threshhold
+    else if(dist  < 325) //Have a bit of a dead zone, otherwise npc will constantly flip between running and not when right on the edge of the running threshhold
         actor.getClass().getCreatureStats(actor).setMovementFlag(MWMechanics::CreatureStats::Flag_Run, false); //make NPC walk
 
     return false;