From 474d53835cec0ad6e054dca3c97c98ae2dcff9f0 Mon Sep 17 00:00:00 2001
From: Daniel Adams <70986246+msub2@users.noreply.github.com>
Date: Sat, 17 Aug 2024 15:49:40 -1000
Subject: [PATCH] Surface predicted display time on Frame object (#240)

Signed-off-by: Daniel Adams <msub2official@gmail.com>
---
 webxr-api/frame.rs    | 3 +++
 webxr/glwindow/mod.rs | 1 +
 webxr/headless/mod.rs | 1 +
 webxr/openxr/mod.rs   | 1 +
 4 files changed, 6 insertions(+)

diff --git a/webxr-api/frame.rs b/webxr-api/frame.rs
index 7f0a3cf..2589953 100644
--- a/webxr-api/frame.rs
+++ b/webxr-api/frame.rs
@@ -33,6 +33,9 @@ pub struct Frame {
 
     /// The hit test results for this frame, if any
     pub hit_test_results: Vec<HitTestResult>,
+
+    /// The average point in time this XRFrame is expected to be displayed on the devices' display
+    pub predicted_display_time: f64,
 }
 
 #[derive(Clone, Debug)]
diff --git a/webxr/glwindow/mod.rs b/webxr/glwindow/mod.rs
index 586bdd4..28eb76b 100644
--- a/webxr/glwindow/mod.rs
+++ b/webxr/glwindow/mod.rs
@@ -192,6 +192,7 @@ impl DeviceAPI for GlWindowDevice {
             events: vec![],
             sub_images,
             hit_test_results: vec![],
+            predicted_display_time: 0.0,
         })
     }
 
diff --git a/webxr/headless/mod.rs b/webxr/headless/mod.rs
index d0decaa..f00ff60 100644
--- a/webxr/headless/mod.rs
+++ b/webxr/headless/mod.rs
@@ -362,6 +362,7 @@ impl HeadlessDeviceData {
             events: vec![],
             sub_images,
             hit_test_results: vec![],
+            predicted_display_time: 0.0,
         }
     }
 
diff --git a/webxr/openxr/mod.rs b/webxr/openxr/mod.rs
index da4dcb2..da9d275 100644
--- a/webxr/openxr/mod.rs
+++ b/webxr/openxr/mod.rs
@@ -1469,6 +1469,7 @@ impl DeviceAPI for OpenXrDevice {
             events: vec![],
             sub_images,
             hit_test_results: vec![],
+            predicted_display_time: frame_state.predicted_display_time.as_nanos() as f64,
         };
 
         if let Some(right_select) = right.select {