From 37696fb38f9d1196b91b37982984de2c65b18832 Mon Sep 17 00:00:00 2001
From: praydog <praydog@praydog.com>
Date: Sun, 10 Dec 2023 00:30:45 -0800
Subject: [PATCH] VR: Possible fix for player view being flung out of existence

---
 src/mods/VR.cpp                    | 16 ++++------------
 src/mods/vr/runtimes/OpenVR.cpp    |  1 +
 src/mods/vr/runtimes/OpenXR.cpp    |  6 +++++-
 src/mods/vr/runtimes/VRRuntime.hpp |  1 +
 4 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/src/mods/VR.cpp b/src/mods/VR.cpp
index 11087879b..bf2994f69 100644
--- a/src/mods/VR.cpp
+++ b/src/mods/VR.cpp
@@ -1342,24 +1342,16 @@ void VR::update_hmd_state() {
     // Update the poses used for the game
     // If we used the data directly from the WaitGetPoses call, we would have to lock a different mutex and wait a long time
     // This is because the WaitGetPoses call is blocking, and we don't want to block any game logic
-    {
+    if (runtime->wants_reset_origin && runtime->ready() && runtime->got_first_valid_poses) {
         std::unique_lock _{ runtime->pose_mtx };
+        set_rotation_offset(glm::identity<glm::quat>());
+        m_standing_origin = get_position_unsafe(vr::k_unTrackedDeviceIndex_Hmd);
 
-        if (runtime->wants_reset_origin && runtime->ready()) {
-            set_rotation_offset(glm::identity<glm::quat>());
-            m_standing_origin = get_position_unsafe(vr::k_unTrackedDeviceIndex_Hmd);
-
-            runtime->wants_reset_origin = false;
-        }
+        runtime->wants_reset_origin = false;
     }
 
     runtime->update_matrices(m_nearz, m_farz);
 
-    // On first run, set the standing origin to the headset position
-    if (!runtime->got_first_poses) {
-        m_standing_origin = get_position(vr::k_unTrackedDeviceIndex_Hmd);
-    }
-
     runtime->got_first_poses = true;
 
     // Forcefully update the camera transform after submitting the frame
diff --git a/src/mods/vr/runtimes/OpenVR.cpp b/src/mods/vr/runtimes/OpenVR.cpp
index 65c427bcd..94ed8dd36 100644
--- a/src/mods/vr/runtimes/OpenVR.cpp
+++ b/src/mods/vr/runtimes/OpenVR.cpp
@@ -12,6 +12,7 @@ VRRuntime::Error OpenVR::synchronize_frame() {
     auto ret = vr::VRCompositor()->WaitGetPoses(this->real_render_poses.data(), vr::k_unMaxTrackedDeviceCount, this->real_game_poses.data(), vr::k_unMaxTrackedDeviceCount);
 
     if (ret == vr::VRCompositorError_None) {
+        this->got_first_valid_poses = true;
         this->got_first_sync = true;
     }
 
diff --git a/src/mods/vr/runtimes/OpenXR.cpp b/src/mods/vr/runtimes/OpenXR.cpp
index ab86f8d2e..21bf3126d 100644
--- a/src/mods/vr/runtimes/OpenXR.cpp
+++ b/src/mods/vr/runtimes/OpenXR.cpp
@@ -63,7 +63,7 @@ VRRuntime::Error OpenXR::update_poses() {
 
     const auto display_time = this->frame_state.predictedDisplayTime + (XrDuration)(this->frame_state.predictedDisplayPeriod * this->prediction_scale);
 
-    if (display_time == 0) {
+    if (display_time <= 1000) {
         return VRRuntime::Error::SUCCESS;
     }
 
@@ -108,6 +108,10 @@ VRRuntime::Error OpenXR::update_poses() {
         }
     }
 
+    if (!this->got_first_valid_poses) {
+        this->got_first_valid_poses = (this->view_space_location.locationFlags & (XR_SPACE_LOCATION_POSITION_VALID_BIT | XR_SPACE_LOCATION_ORIENTATION_VALID_BIT)) != 0;
+    }
+
     this->needs_pose_update = false;
     this->got_first_poses = true;
     return VRRuntime::Error::SUCCESS;
diff --git a/src/mods/vr/runtimes/VRRuntime.hpp b/src/mods/vr/runtimes/VRRuntime.hpp
index 783b97fed..6fb56fdc1 100644
--- a/src/mods/vr/runtimes/VRRuntime.hpp
+++ b/src/mods/vr/runtimes/VRRuntime.hpp
@@ -111,6 +111,7 @@ struct VRRuntime {
     // will return VRCompositorError_DoNotHaveFocus
     bool needs_pose_update{true};
     bool got_first_poses{false};
+    bool got_first_valid_poses{false};
     bool got_first_sync{false};
     bool handle_pause{false};
     bool wants_reset_origin{true};