From 335c60e6b8afd91e7cda6eb1ccca34668286a545 Mon Sep 17 00:00:00 2001
From: Anthony Thibault <tony@highfidelity.io>
Date: Fri, 5 Oct 2018 17:29:25 -0700
Subject: [PATCH] Reduce the glitches of far away animating avatars

Currently, the avatars that are further then 10 meters away have a
very aggressive 15 degree rotation threshold, used to reduce the
amount of rotation joint changes sent over the network.

This PR tunes both the distances and rotation thresholds used for
this LOD culling.
---
 libraries/avatars/src/AvatarData.cpp |  8 +++++---
 libraries/avatars/src/AvatarData.h   | 21 ++++++++++++---------
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/libraries/avatars/src/AvatarData.cpp b/libraries/avatars/src/AvatarData.cpp
index 5fb4ef3156..5930b79074 100644
--- a/libraries/avatars/src/AvatarData.cpp
+++ b/libraries/avatars/src/AvatarData.cpp
@@ -206,11 +206,13 @@ float AvatarData::getDistanceBasedMinRotationDOT(glm::vec3 viewerPosition) const
     if (distance < AVATAR_DISTANCE_LEVEL_1) {
         result = AVATAR_MIN_ROTATION_DOT;
     } else if (distance < AVATAR_DISTANCE_LEVEL_2) {
-        result = ROTATION_CHANGE_15D;
+        result = ROTATION_CHANGE_2D;
     } else if (distance < AVATAR_DISTANCE_LEVEL_3) {
-        result = ROTATION_CHANGE_45D;
+        result = ROTATION_CHANGE_4D;
     } else if (distance < AVATAR_DISTANCE_LEVEL_4) {
-        result = ROTATION_CHANGE_90D;
+        result = ROTATION_CHANGE_6D;
+    } else if (distance < AVATAR_DISTANCE_LEVEL_5) {
+        result = ROTATION_CHANGE_15D;
     }
     return result;
 }
diff --git a/libraries/avatars/src/AvatarData.h b/libraries/avatars/src/AvatarData.h
index 860772b7c9..46489451f7 100644
--- a/libraries/avatars/src/AvatarData.h
+++ b/libraries/avatars/src/AvatarData.h
@@ -309,16 +309,19 @@ const float AVATAR_SEND_FULL_UPDATE_RATIO = 0.02f;
 const float AVATAR_MIN_ROTATION_DOT = 0.9999999f;
 const float AVATAR_MIN_TRANSLATION = 0.0001f;
 
-const float ROTATION_CHANGE_15D = 0.9914449f;
-const float ROTATION_CHANGE_45D = 0.9238795f;
-const float ROTATION_CHANGE_90D = 0.7071068f;
-const float ROTATION_CHANGE_179D = 0.0087266f;
-
-const float AVATAR_DISTANCE_LEVEL_1 = 10.0f;
-const float AVATAR_DISTANCE_LEVEL_2 = 100.0f;
-const float AVATAR_DISTANCE_LEVEL_3 = 1000.0f;
-const float AVATAR_DISTANCE_LEVEL_4 = 10000.0f;
+// quaternion dot products
+const float ROTATION_CHANGE_2D = 0.99984770f; // 2 degrees
+const float ROTATION_CHANGE_4D = 0.99939083f; // 4 degrees
+const float ROTATION_CHANGE_6D = 0.99862953f; // 6 degrees
+const float ROTATION_CHANGE_15D = 0.99144486f; // 15 degrees
+const float ROTATION_CHANGE_179D = 0.00872653f; // 179 degrees
 
+// rotation culling distance thresholds
+const float AVATAR_DISTANCE_LEVEL_1 = 12.5f; // meters
+const float AVATAR_DISTANCE_LEVEL_2 = 16.6f; // meters
+const float AVATAR_DISTANCE_LEVEL_3 = 25.0f; // meters
+const float AVATAR_DISTANCE_LEVEL_4 = 50.0f; // meters
+const float AVATAR_DISTANCE_LEVEL_5 = 200.0f; // meters
 
 // Where one's own Avatar begins in the world (will be overwritten if avatar data file is found).
 // This is the start location in the Sandbox (xyz: 6270, 211, 6000).