From 94ee6d683882e7bd8762fa37fafe2c5d88c2c6a0 Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Thu, 30 Mar 2017 13:24:12 -0700
Subject: [PATCH] fix driving motion of collisionless avatars

---
 interface/src/avatar/MyAvatar.cpp             |  5 ++--
 libraries/physics/src/CharacterController.cpp | 30 +++++++++++++------
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/interface/src/avatar/MyAvatar.cpp b/interface/src/avatar/MyAvatar.cpp
index 2aa446045e..7104a14f0a 100755
--- a/interface/src/avatar/MyAvatar.cpp
+++ b/interface/src/avatar/MyAvatar.cpp
@@ -1883,8 +1883,9 @@ void MyAvatar::updateActionMotor(float deltaTime) {
 
     glm::vec3 direction = forward + right;
     CharacterController::State state = _characterController.getState();
-    if (state == CharacterController::State::Hover) {
-        // we're flying --> support vertical motion
+    if (state == CharacterController::State::Hover ||
+            _characterController.getCollisionGroup() == BULLET_COLLISION_GROUP_COLLISIONLESS) {
+        // we can fly --> support vertical motion
         glm::vec3 up = (getDriveKey(TRANSLATE_Y)) * IDENTITY_UP;
         direction += up;
     }
diff --git a/libraries/physics/src/CharacterController.cpp b/libraries/physics/src/CharacterController.cpp
index 40ca3a0826..95fcb27684 100755
--- a/libraries/physics/src/CharacterController.cpp
+++ b/libraries/physics/src/CharacterController.cpp
@@ -400,8 +400,12 @@ void CharacterController::handleChangedCollisionGroup() {
         }
         _pendingFlags &= ~PENDING_FLAG_UPDATE_COLLISION_GROUP;
 
-        if (_state != State::Hover && _rigidBody) {
-            _gravity = _collisionGroup == BULLET_COLLISION_GROUP_COLLISIONLESS ? 0.0f : DEFAULT_CHARACTER_GRAVITY;
+        if (_collisionGroup == BULLET_COLLISION_GROUP_COLLISIONLESS) {
+            _gravity = 0.0f;
+        } else if (_state != State::Hover) {
+            _gravity = (_collisionGroup == BULLET_COLLISION_GROUP_COLLISIONLESS) ? 0.0f : DEFAULT_CHARACTER_GRAVITY;
+        }
+        if (_rigidBody) {
             _rigidBody->setGravity(_gravity * _currentUp);
         }
     }
@@ -630,8 +634,12 @@ void CharacterController::updateState() {
     // rayStart is at center of bottom sphere
     btVector3 rayStart = _position;
 
-    // rayEnd is straight down MAX_FALL_HEIGHT
-    btScalar rayLength = _radius + MAX_FALL_HEIGHT;
+    btScalar rayLength = _radius;
+    if (_collisionGroup == BULLET_COLLISION_GROUP_MY_AVATAR) {
+        rayLength += MAX_FALL_HEIGHT;
+    } else {
+        rayLength += MIN_HOVER_HEIGHT;
+    }
     btVector3 rayEnd = rayStart - rayLength * _currentUp;
 
     ClosestNotMe rayCallback(_rigidBody);
@@ -663,6 +671,7 @@ void CharacterController::updateState() {
     btVector3 velocity = _preSimulationVelocity;
 
     // disable normal state transitions while collisionless
+    const btScalar MAX_WALKING_SPEED = 2.65f;
     if (_collisionGroup == BULLET_COLLISION_GROUP_MY_AVATAR) {
         switch (_state) {
         case State::Ground:
@@ -703,9 +712,8 @@ void CharacterController::updateState() {
             break;
         }
         case State::Hover:
-            btVector3 actualHorizVelocity = velocity - velocity.dot(_currentUp) * _currentUp;
-            const btScalar MAX_WALKING_SPEED = 2.5f;
-            bool flyingFast = _state == State::Hover && actualHorizVelocity.length() > (MAX_WALKING_SPEED * 0.75f);
+            btScalar horizontalSpeed = (velocity - velocity.dot(_currentUp) * _currentUp).length();
+            bool flyingFast = _state == State::Hover && horizontalSpeed > (MAX_WALKING_SPEED * 0.75f);
 
             if ((_floorDistance < MIN_HOVER_HEIGHT) &&
                     !(jumpButtonHeld || flyingFast || (now - _jumpButtonDownStartTime) > JUMP_TO_HOVER_PERIOD)) {
@@ -716,9 +724,13 @@ void CharacterController::updateState() {
             break;
         }
     } else {
-        // in collisionless state switch only between Ground and Hover states
+        // when collisionless: only switch between State::Ground and State::Hover
         if (rayHasHit) {
-            SET_STATE(State::Ground, "collisionless above ground");
+            if (velocity.length() > (MAX_WALKING_SPEED)) {
+                SET_STATE(State::Hover, "collisionless in air");
+            } else {
+                SET_STATE(State::Ground, "collisionless above ground");
+            }
         } else {
             SET_STATE(State::Hover, "collisionless in air");
         }