Filled scene to generate nonblack image

Author: bugsweeper

examples/app/headless_renderer.rs

@@ -80,6 +80,8 @@ fn main() {
 
 fn setup(
     mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
     mut images: ResMut<Assets<Image>>,
     mut scene_controller: ResMut<frame_capture::scene::SceneController>,
     render_device: Res<RenderDevice>,
@@ -89,16 +91,49 @@ fn setup(
         &mut images,
         &render_device,
         &mut scene_controller,
-        15,
+        // pre_roll_frames should be big enought for full scene render,
+        // but the bigger it is, the longer example will run.
+        // To visualize stages of scene rendering change this param to 0
+        // and change AppConfig::single_image to false in main
+        // Stages are:
+        // 1. Transparent image
+        // 2. Few black box images
+        // 3. Fully rendered scene images
+        // Exact number depends on device speed, device load and scene size
+        30,
         "main_scene".into(),
     );
 
-    // Scene is empty, but you can add any mesh to generate non black box picture
+    // Scene example for non black box picture
+    // circular base
+    commands.spawn(PbrBundle {
+        mesh: meshes.add(Circle::new(4.0)),
+        material: materials.add(Color::WHITE),
+        transform: Transform::from_rotation(Quat::from_rotation_x(-std::f32::consts::FRAC_PI_2)),
+        ..default()
+    });
+    // cube
+    commands.spawn(PbrBundle {
+        mesh: meshes.add(Cuboid::new(1.0, 1.0, 1.0)),
+        material: materials.add(Color::srgb_u8(124, 144, 255)),
+        transform: Transform::from_xyz(0.0, 0.5, 0.0),
+        ..default()
+    });
+    // light
+    commands.spawn(PointLightBundle {
+        point_light: PointLight {
+            shadows_enabled: true,
+            ..default()
+        },
+        transform: Transform::from_xyz(4.0, 8.0, 4.0),
+        ..default()
+    });
 
     commands.spawn(Camera3dBundle {
-        transform: Transform::from_xyz(0.0, 6., 12.0).looking_at(Vec3::new(0., 1., 0.), Vec3::Y),
+        transform: Transform::from_xyz(-2.5, 4.5, 9.0).looking_at(Vec3::ZERO, Vec3::Y),
         tonemapping: Tonemapping::None,
         camera: Camera {
+            // render to image
             target: render_target,
             ..default()
         },
@@ -469,10 +504,16 @@ mod frame_capture {
 
                     // We don't want to block the main world on this,
                     // so we use try_recv which attempts to receive without blocking
+                    let mut image_data = Vec::new();
                     while let Ok(data) = receiver.try_recv() {
+                        // image generation could be faster than saving to fs,
+                        // that's why use only last of them
+                        image_data = data;
+                    }
+                    if !image_data.is_empty() {
                         for image in images_to_save.iter() {
                             let img_bytes = images.get_mut(image.id()).unwrap();
-                            img_bytes.data = data.clone();
+                            img_bytes.data = image_data.clone();
 
                             let img = match img_bytes.clone().try_into_dynamic() {
                                 Ok(img) => img.to_rgba8(),
@@ -492,7 +533,6 @@ mod frame_capture {
                         }
                         if scene_controller.single_image {
                             app_exit_writer.send(AppExit::Success);
-                            break;
                         }
                     }
                 } else {