Easy screenrecording plugin (#21237)

# Objective

- Followup on #21235
- See
mockersf/bevy@easy-screenshots...mockersf:bevy:easy-screenrecording
for what's new
- Be able to record videos from Bevy in a consistent manner

## Solution

- Make a new `EasyScreenRecordPlugin` in the dev tools

## Testing

- Add to any example
```
        .add_plugins(bevy::dev_tools::EasyScreenRecordPlugin::default())
```
- Run the example with the feature `bevy_internal/screenrecording`
enabled
- press the space bar
- wait for it...
- press the space bar again
- screen recording! 🎉 
- almost... you now have a h264 file. VLC can read them, but they are
not the most friendly format
- `ffmpeg` is our friend! `for file in *.h264; do ffmpeg -i $file
$file.mp4; done`
- you now have a .mp4 file that can be shared anywhere!

---

## Showcase

directly taken by Bevy


https://github.com/user-attachments/assets/217f5093-9443-40e5-b2ce-33f65f6a56c6

Author: mockersf

.github/actions/install-linux-deps/action.yml

@@ -33,6 +33,10 @@ inputs:
     description: Install xkb (libxkbcommon-dev)
     required: false
     default: "false"
+  x264:
+    description: Install x264 (libx264-dev)
+    required: false
+    default: "false"
 runs:
   using: composite
   steps:
@@ -47,3 +51,4 @@ runs:
         ${{ fromJSON(inputs.udev) && 'libudev-dev' || '' }}
         ${{ fromJSON(inputs.wayland) && 'libwayland-dev' || '' }}
         ${{ fromJSON(inputs.xkb) && 'libxkbcommon-dev' || '' }}
+        ${{ fromJSON(inputs.x264) && 'libx264-164 libx264-dev' || '' }}

.github/workflows/ci.yml

@@ -83,6 +83,7 @@ jobs:
         with:
           wayland: true
           xkb: true
+          x264: true
       - name: CI job
         # See tools/ci/src/main.rs for the commands this runs
         run: cargo run -p ci -- lints
@@ -371,6 +372,7 @@ jobs:
         with:
           wayland: true
           xkb: true
+          x264: true
       - name: Build and check doc
         # See tools/ci/src/main.rs for the commands this runs
         run: cargo run -p ci -- doc

crates/bevy_dev_tools/Cargo.toml

@@ -10,6 +10,7 @@ keywords = ["bevy"]
 
 [features]
 bevy_ci_testing = ["serde", "ron"]
+screenrecording = ["x264"]
 webgl = ["bevy_render/webgl"]
 webgpu = ["bevy_render/webgpu"]
 
@@ -21,6 +22,7 @@ bevy_camera = { path = "../bevy_camera", version = "0.18.0-dev" }
 bevy_color = { path = "../bevy_color", version = "0.18.0-dev" }
 bevy_diagnostic = { path = "../bevy_diagnostic", version = "0.18.0-dev" }
 bevy_ecs = { path = "../bevy_ecs", version = "0.18.0-dev" }
+bevy_image = { path = "../bevy_image", version = "0.18.0-dev" }
 bevy_input = { path = "../bevy_input", version = "0.18.0-dev" }
 bevy_math = { path = "../bevy_math", version = "0.18.0-dev" }
 bevy_picking = { path = "../bevy_picking", version = "0.18.0-dev" }
@@ -38,6 +40,7 @@ bevy_state = { path = "../bevy_state", version = "0.18.0-dev" }
 serde = { version = "1.0", features = ["derive"], optional = true }
 ron = { version = "0.12", optional = true }
 tracing = { version = "0.1", default-features = false, features = ["std"] }
+x264 = { version = "0.5.0", optional = true }
 
 [lints]
 workspace = true

crates/bevy_dev_tools/src/easy_screenshot.rs

@@ -1,10 +1,26 @@
+#[cfg(feature = "screenrecording")]
+use core::time::Duration;
 use std::time::{SystemTime, UNIX_EPOCH};
+#[cfg(feature = "screenrecording")]
+use std::{fs::File, io::Write, sync::mpsc::channel};
 
 use bevy_app::{App, Plugin, Update};
 use bevy_ecs::prelude::*;
+#[cfg(feature = "screenrecording")]
+use bevy_image::Image;
 use bevy_input::{common_conditions::input_just_pressed, keyboard::KeyCode};
+#[cfg(feature = "screenrecording")]
+use bevy_render::view::screenshot::ScreenshotCaptured;
 use bevy_render::view::screenshot::{save_to_disk, Screenshot};
+#[cfg(feature = "screenrecording")]
+use bevy_time::Time;
 use bevy_window::{PrimaryWindow, Window};
+#[cfg(feature = "screenrecording")]
+use tracing::info;
+#[cfg(feature = "screenrecording")]
+use x264::{Colorspace, Encoder, Setup};
+#[cfg(feature = "screenrecording")]
+pub use x264::{Preset, Tune};
 
 /// File format the screenshot will be saved in
 #[derive(Clone, Copy)]
@@ -65,3 +81,179 @@ impl Plugin for EasyScreenshotPlugin {
         );
     }
 }
+
+#[cfg(feature = "screenrecording")]
+/// Add this plugin to your app to enable easy screen recording.
+pub struct EasyScreenRecordPlugin {
+    /// The key to toggle recording.
+    pub toggle: KeyCode,
+    /// h264 encoder preset
+    pub preset: Preset,
+    /// h264 encoder tune
+    pub tune: Tune,
+    /// target frame time
+    pub frame_time: Duration,
+}
+
+#[cfg(feature = "screenrecording")]
+impl Default for EasyScreenRecordPlugin {
+    fn default() -> Self {
+        EasyScreenRecordPlugin {
+            toggle: KeyCode::Space,
+            preset: Preset::Medium,
+            tune: Tune::Animation,
+            frame_time: Duration::from_millis(33),
+        }
+    }
+}
+
+#[cfg(feature = "screenrecording")]
+enum RecordCommand {
+    Start(String, Preset, Tune),
+    Stop,
+    Frame(Image),
+}
+
+#[cfg(feature = "screenrecording")]
+/// Controls screen recording
+#[derive(Message)]
+pub enum RecordScreen {
+    /// Starts screen recording
+    Start,
+    /// Stops screen recording
+    Stop,
+}
+
+#[cfg(feature = "screenrecording")]
+impl Plugin for EasyScreenRecordPlugin {
+    fn build(&self, app: &mut App) {
+        let (tx, rx) = channel::<RecordCommand>();
+
+        let frame_time = self.frame_time;
+
+        std::thread::spawn(move || {
+            let mut encoder: Option<Encoder> = None;
+            let mut setup = None;
+            let mut file: Option<File> = None;
+            let mut frame = 0;
+            loop {
+                let Ok(next) = rx.recv() else {
+                    break;
+                };
+                match next {
+                    RecordCommand::Start(name, preset, tune) => {
+                        info!("starting recording at {}", name);
+                        file = Some(File::create(name).unwrap());
+                        setup = Some(Setup::preset(preset, tune, false, true).high());
+                    }
+                    RecordCommand::Stop => {
+                        info!("stopping recording");
+                        if let Some(encoder) = encoder.take() {
+                            let mut flush = encoder.flush();
+                            let mut file = file.take().unwrap();
+                            while let Some(result) = flush.next() {
+                                let (data, _) = result.unwrap();
+                                file.write_all(data.entirety()).unwrap();
+                            }
+                        }
+                    }
+                    RecordCommand::Frame(image) => {
+                        if let Some(setup) = setup.take() {
+                            let mut new_encoder = setup
+                                .fps((1000 / frame_time.as_millis()) as u32, 1)
+                                .build(Colorspace::RGB, image.width() as i32, image.height() as i32)
+                                .unwrap();
+                            let headers = new_encoder.headers().unwrap();
+                            file.as_mut()
+                                .unwrap()
+                                .write_all(headers.entirety())
+                                .unwrap();
+                            encoder = Some(new_encoder);
+                        }
+                        if let Some(encoder) = encoder.as_mut() {
+                            let pts = (frame_time.as_millis() * frame) as i64;
+
+                            frame += 1;
+                            let (data, _) = encoder
+                                .encode(
+                                    pts,
+                                    x264::Image::rgb(
+                                        image.width() as i32,
+                                        image.height() as i32,
+                                        &image.try_into_dynamic().unwrap().to_rgb8(),
+                                    ),
+                                )
+                                .unwrap();
+                            file.as_mut().unwrap().write_all(data.entirety()).unwrap();
+                        }
+                    }
+                }
+            }
+        });
+
+        let frame_time = self.frame_time;
+
+        app.add_message::<RecordScreen>().add_systems(
+            Update,
+            (
+                (move |mut messages: MessageWriter<RecordScreen>, mut recording: Local<bool>| {
+                    *recording = !*recording;
+                    if *recording {
+                        messages.write(RecordScreen::Start);
+                    } else {
+                        messages.write(RecordScreen::Stop);
+                    }
+                })
+                .run_if(input_just_pressed(self.toggle)),
+                {
+                    let tx = tx.clone();
+                    let preset = self.preset;
+                    let tune = self.tune;
+                    move |mut commands: Commands,
+                          mut recording: Local<bool>,
+                          mut messages: MessageReader<RecordScreen>,
+                          window: Single<&Window, With<PrimaryWindow>>,
+                          current_screenshot: Query<(), With<Screenshot>>,
+                          mut virtual_time: ResMut<Time<bevy_time::Virtual>>| {
+                        match messages.read().last() {
+                            Some(RecordScreen::Start) => {
+                                let since_the_epoch = SystemTime::now()
+                                    .duration_since(UNIX_EPOCH)
+                                    .expect("time should go forward");
+                                let filename = format!(
+                                    "{}-{}.h264",
+                                    window.title,
+                                    since_the_epoch.as_millis(),
+                                );
+                                tx.send(RecordCommand::Start(filename, preset, tune))
+                                    .unwrap();
+                                *recording = true;
+                                virtual_time.pause();
+                            }
+                            Some(RecordScreen::Stop) => {
+                                tx.send(RecordCommand::Stop).unwrap();
+                                *recording = false;
+                                virtual_time.unpause();
+                            }
+                            _ => {}
+                        }
+                        if *recording && current_screenshot.single().is_err() {
+                            let tx = tx.clone();
+                            commands.spawn(Screenshot::primary_window()).observe(
+                                move |screenshot_captured: On<ScreenshotCaptured>,
+                                      mut virtual_time: ResMut<Time<bevy_time::Virtual>>,
+                                      mut time: ResMut<Time<()>>| {
+                                    let img = screenshot_captured.image.clone();
+                                    tx.send(RecordCommand::Frame(img)).unwrap();
+                                    virtual_time.advance_by(frame_time);
+                                    *time = virtual_time.as_generic();
+                                },
+                            );
+                        }
+                    }
+                },
+            )
+                .chain(),
+        );
+    }
+}

crates/bevy_internal/Cargo.toml

@@ -430,6 +430,8 @@ hotpatching = ["bevy_app/hotpatching", "bevy_ecs/hotpatching"]
 
 debug = ["bevy_utils/debug", "bevy_ecs/debug"]
 
+screenrecording = ["bevy_dev_tools/screenrecording"]
+
 [dependencies]
 # bevy (no_std)
 bevy_app = { path = "../bevy_app", version = "0.18.0-dev", default-features = false, features = [

release-content/release-notes/easy_marketing_material.md

@@ -0,0 +1,9 @@
+---
+title: Helpers to Produce Marketing Material
+authors: ["@mockersf"]
+pull_requests: [21235, 21237]
+---
+
+Bevy can take a screenshot of what's rendered since 0.11. This is now easier to setup to help you create marketing material, so that you can take screenshot with consistent formatting with the new `EasyScreenshotPlugin`. With its default settings, once you add this plugin to your application, a PNG screenshot will be taken when you press the `PrintScreen` key. You can change the trigger key, or the screenshot format between PNG, JPEG or BMP.
+
+It is now possible to record a movie from Bevy, with the new `EasyScreenRecordPlugin`. This plugins add a toggle key, space bar by default, that will toggle screen recording. Recording can also be started and stopped programmatically with the `RecordScreen` messages.