From b1c906e66f0e16d6a8bd0fbba88b89a289194b93 Mon Sep 17 00:00:00 2001
From: Robert Swain <robert.swain@gmail.com>
Date: Wed, 2 Dec 2020 16:28:51 +0100
Subject: [PATCH 1/5] Display fps and frame time in text_debug example

---
 examples/ui/text_debug.rs | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/examples/ui/text_debug.rs b/examples/ui/text_debug.rs
index 856e934efd0a8..aed3ff774817b 100644
--- a/examples/ui/text_debug.rs
+++ b/examples/ui/text_debug.rs
@@ -1,10 +1,13 @@
-use bevy::prelude::*;
-extern crate rand;
+use bevy::{
+    diagnostic::{Diagnostics, FrameTimeDiagnosticsPlugin},
+    prelude::*,
+};
 
 /// This example is for debugging text layout
 fn main() {
     App::build()
         .add_plugins(DefaultPlugins)
+        .add_plugin(FrameTimeDiagnosticsPlugin)
         .add_startup_system(infotext_system)
         .add_system(change_text_system)
         .run();
@@ -83,7 +86,7 @@ fn infotext_system(commands: &mut Commands, asset_server: Res<AssetServer>) {
                 value: "This text changes in the bottom right".to_string(),
                 font: font.clone(),
                 style: TextStyle {
-                    font_size: 50.0,
+                    font_size: 30.0,
                     color: Color::WHITE,
                     alignment: TextAlignment::default(),
                 },
@@ -120,11 +123,23 @@ fn infotext_system(commands: &mut Commands, asset_server: Res<AssetServer>) {
     });
 }
 
-fn change_text_system(mut query: Query<(&mut Text, &TextChanges)>) {
+fn change_text_system(
+    time: Res<Time>,
+    diagnostics: Res<Diagnostics>,
+    mut query: Query<(&mut Text, &TextChanges)>,
+) {
     for (mut text, _text_changes) in query.iter_mut() {
+        let mut fps = 0.0;
+        if let Some(fps_diagnostic) = diagnostics.get(FrameTimeDiagnosticsPlugin::FPS) {
+            if let Some(fps_avg) = fps_diagnostic.average() {
+                fps = fps_avg;
+            }
+        }
+
         text.value = format!(
-            "This text changes in the bottom right {}",
-            rand::random::<u16>(),
+            "This text changes in the bottom right - {:.1} fps, {:.3} ms/frame",
+            fps,
+            time.delta_seconds_f64() * 1000.0,
         );
     }
 }

From b9a584a2f3d9eda80aa98626b329749fe18cee66 Mon Sep 17 00:00:00 2001
From: Robert Swain <robert.swain@gmail.com>
Date: Wed, 2 Dec 2020 16:29:20 +0100
Subject: [PATCH 2/5] Disable vsync in text_debug example to show frame time /
 fps performance

---
 examples/ui/text_debug.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/examples/ui/text_debug.rs b/examples/ui/text_debug.rs
index aed3ff774817b..b250f95706c2c 100644
--- a/examples/ui/text_debug.rs
+++ b/examples/ui/text_debug.rs
@@ -6,6 +6,10 @@ use bevy::{
 /// This example is for debugging text layout
 fn main() {
     App::build()
+        .add_resource(WindowDescriptor {
+            vsync: false,
+            ..Default::default()
+        })
         .add_plugins(DefaultPlugins)
         .add_plugin(FrameTimeDiagnosticsPlugin)
         .add_startup_system(infotext_system)

From 8df4bb1e35c09964fcd18dd435656ebc6799ea7e Mon Sep 17 00:00:00 2001
From: Robert Swain <robert.swain@gmail.com>
Date: Wed, 2 Dec 2020 16:42:15 +0100
Subject: [PATCH 3/5] Display average frame time

---
 examples/ui/text_debug.rs | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/examples/ui/text_debug.rs b/examples/ui/text_debug.rs
index b250f95706c2c..93c76e7f8c850 100644
--- a/examples/ui/text_debug.rs
+++ b/examples/ui/text_debug.rs
@@ -140,10 +140,17 @@ fn change_text_system(
             }
         }
 
+        let mut frame_time = time.delta_seconds_f64();
+        if let Some(frame_time_diagnostic) = diagnostics.get(FrameTimeDiagnosticsPlugin::FRAME_TIME) {
+            if let Some(frame_time_avg) = frame_time_diagnostic.average() {
+                frame_time = frame_time_avg;
+            }
+        }
+
         text.value = format!(
             "This text changes in the bottom right - {:.1} fps, {:.3} ms/frame",
             fps,
-            time.delta_seconds_f64() * 1000.0,
+            frame_time * 1000.0,
         );
     }
 }

From 8ba3bd97c22ec3c7d66058fc93b7fc91dc8fecb0 Mon Sep 17 00:00:00 2001
From: Robert Swain <robert.swain@gmail.com>
Date: Thu, 3 Dec 2020 00:01:05 +0100
Subject: [PATCH 4/5] Fix formatting in text_debug example

---
 examples/ui/text_debug.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/examples/ui/text_debug.rs b/examples/ui/text_debug.rs
index 93c76e7f8c850..f5db35f5b90a3 100644
--- a/examples/ui/text_debug.rs
+++ b/examples/ui/text_debug.rs
@@ -141,7 +141,8 @@ fn change_text_system(
         }
 
         let mut frame_time = time.delta_seconds_f64();
-        if let Some(frame_time_diagnostic) = diagnostics.get(FrameTimeDiagnosticsPlugin::FRAME_TIME) {
+        if let Some(frame_time_diagnostic) = diagnostics.get(FrameTimeDiagnosticsPlugin::FRAME_TIME)
+        {
             if let Some(frame_time_avg) = frame_time_diagnostic.average() {
                 frame_time = frame_time_avg;
             }

From df0c25bb0cc8208d8a0e0d3217184e0a88a1c962 Mon Sep 17 00:00:00 2001
From: Robert Swain <robert.swain@gmail.com>
Date: Thu, 3 Dec 2020 00:01:26 +0100
Subject: [PATCH 5/5] Use With query for unused component in text_debug example

---
 examples/ui/text_debug.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/examples/ui/text_debug.rs b/examples/ui/text_debug.rs
index f5db35f5b90a3..ffa1078038e54 100644
--- a/examples/ui/text_debug.rs
+++ b/examples/ui/text_debug.rs
@@ -130,9 +130,9 @@ fn infotext_system(commands: &mut Commands, asset_server: Res<AssetServer>) {
 fn change_text_system(
     time: Res<Time>,
     diagnostics: Res<Diagnostics>,
-    mut query: Query<(&mut Text, &TextChanges)>,
+    mut query: Query<&mut Text, With<TextChanges>>,
 ) {
-    for (mut text, _text_changes) in query.iter_mut() {
+    for mut text in query.iter_mut() {
         let mut fps = 0.0;
         if let Some(fps_diagnostic) = diagnostics.get(FrameTimeDiagnosticsPlugin::FPS) {
             if let Some(fps_avg) = fps_diagnostic.average() {