From 22d3d65ed536ceed221b594f14fac71b4161d490 Mon Sep 17 00:00:00 2001
From: Riccardo Zaglia <riccardo.zaglia5@gmail.com>
Date: Fri, 17 Jan 2025 22:31:28 +0100
Subject: [PATCH] Add Max prediction setting

---
 alvr/client_core/src/connection.rs | 2 ++
 alvr/client_core/src/lib.rs        | 8 ++++----
 alvr/session/src/settings.rs       | 8 ++++++++
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/alvr/client_core/src/connection.rs b/alvr/client_core/src/connection.rs
index 8050cac1fd..3c3e8db1a9 100644
--- a/alvr/client_core/src/connection.rs
+++ b/alvr/client_core/src/connection.rs
@@ -70,6 +70,7 @@ pub struct ConnectionContext {
     pub view_params: RwLock<[ViewParams; 2]>,
     pub uses_multimodal_protocol: RelaxedAtomic,
     pub velocities_multiplier: RwLock<f32>,
+    pub max_prediction: RwLock<Duration>,
 }
 
 fn set_hud_message(event_queue: &Mutex<VecDeque<ClientCoreEvent>>, message: &str) {
@@ -205,6 +206,7 @@ fn connection_pipeline(
     let negotiated_config = stream_config.negotiated_config;
 
     *ctx.velocities_multiplier.write() = settings.extra.velocities_multiplier;
+    *ctx.max_prediction.write() = Duration::from_millis(settings.headset.max_prediction_ms);
 
     *ctx.statistics_manager.lock() = Some(StatisticsManager::new(
         settings.connection.statistics_history_size,
diff --git a/alvr/client_core/src/lib.rs b/alvr/client_core/src/lib.rs
index 106adc3f24..81d4fbd3fc 100644
--- a/alvr/client_core/src/lib.rs
+++ b/alvr/client_core/src/lib.rs
@@ -42,8 +42,6 @@ use storage::Config;
 pub use alvr_system_info::Platform;
 pub use logging_backend::init_logging;
 
-pub const MAX_PREDICTION: Duration = Duration::from_millis(100);
-
 pub enum ClientCoreEvent {
     UpdateHudMessage(String),
     StreamingStarted(Box<StreamConfig>),
@@ -236,10 +234,12 @@ impl ClientCoreContext {
     ) {
         dbg_client_core!("send_tracking");
 
+        let max_prediction = *self.connection_context.max_prediction.read();
+
         let target_timestamp = if let Some(stats) =
             &*self.connection_context.statistics_manager.lock()
         {
-            poll_timestamp + Duration::max(stats.average_total_pipeline_latency(), MAX_PREDICTION)
+            poll_timestamp + Duration::max(stats.average_total_pipeline_latency(), max_prediction)
         } else {
             poll_timestamp
         };
@@ -266,7 +266,7 @@ impl ClientCoreContext {
                 motion.angular_velocity = Vec3::ZERO;
             } else if let Some(stats) = &*self.connection_context.statistics_manager.lock() {
                 let tracker_timestamp = poll_timestamp
-                    + Duration::max(stats.tracker_prediction_offset(), MAX_PREDICTION);
+                    + Duration::max(stats.tracker_prediction_offset(), max_prediction);
 
                 *motion = motion.predict(poll_timestamp, tracker_timestamp);
             }
diff --git a/alvr/session/src/settings.rs b/alvr/session/src/settings.rs
index 5dc39959ff..2447bb4859 100644
--- a/alvr/session/src/settings.rs
+++ b/alvr/session/src/settings.rs
@@ -1109,6 +1109,13 @@ Tilted: the world gets tilted when long pressing the oculus button. This is usef
     #[schema(flag = "steamvr-restart")]
     #[schema(strings(display_name = "VMC"))]
     pub vmc: Switch<VMCConfig>,
+
+    #[schema(strings(
+        help = "Maximum prediction for head and controllers. Used to avoid too much jitter during loading."
+    ))]
+    #[schema(flag = "real-time")]
+    #[schema(gui(slider(min = 0, max = 500, step = 10)), suffix = "ms")]
+    pub max_prediction_ms: u64,
 }
 
 #[derive(SettingsSchema, Serialize, Deserialize, Clone, Copy)]
@@ -1823,6 +1830,7 @@ pub fn session_settings_default() -> SettingsDefault {
             rotation_recentering_mode: RotationRecenteringModeDefault {
                 variant: RotationRecenteringModeDefaultVariant::Yaw,
             },
+            max_prediction_ms: 100,
         },
         connection: ConnectionConfigDefault {
             stream_protocol: SocketProtocolDefault {