Base AiFollow activation range on follow distance (bug #7685)

CHANGELOG.md

@@ -103,6 +103,7 @@
     Bug #7665: Alchemy menu is missing the ability to deselect and choose different qualities of an apparatus
     Bug #7675: Successful lock spell doesn't produce a sound
     Bug #7679: Scene luminance value flashes when toggling shaders
+    Bug #7685: Corky sometimes doesn't follow Llovyn Andus
     Bug #7712: Casting doesn't support spells and enchantments with no effects
     Feature #3537: Shader-based water ripples
     Feature #5173: Support for NiFogProperty

apps/openmw/mwmechanics/aifollow.cpp

@@ -119,21 +119,6 @@ namespace MWMechanics
         const osg::Vec3f targetPos(target.getRefData().getPosition().asVec3());
         const osg::Vec3f targetDir = targetPos - actorPos;
 
-        // AiFollow requires the target to be in range and within sight for the initial activation
-        if (!mActive)
-        {
-            storage.mTimer -= duration;
-
-            if (storage.mTimer < 0)
-            {
-                if (targetDir.length2() < 500 * 500 && MWBase::Environment::get().getWorld()->getLOS(actor, target))
-                    mActive = true;
-                storage.mTimer = 0.5f;
-            }
-        }
-        if (!mActive)
-            return false;
-
         // In the original engine the first follower stays closer to the player than any subsequent followers.
         // Followers beyond the first usually attempt to stand inside each other.
         osg::Vec3f::value_type floatingDistance = 0;
@@ -152,6 +137,23 @@ namespace MWMechanics
         floatingDistance += getHalfExtents(actor) * 2;
         short followDistance = static_cast<short>(floatingDistance);
 
+        // AiFollow requires the target to be in range and within sight for the initial activation
+        if (!mActive)
+        {
+            storage.mTimer -= duration;
+
+            if (storage.mTimer < 0)
+            {
+                float activeRange = followDistance + 384.f;
+                if (targetDir.length2() < activeRange * activeRange
+                    && MWBase::Environment::get().getWorld()->getLOS(actor, target))
+                    mActive = true;
+                storage.mTimer = 0.5f;
+            }
+        }
+        if (!mActive)
+            return false;
+
         if (!mAlwaysFollow) // Update if you only follow for a bit
         {
             // Check if we've run out of time