From b414243baa82c7c9ff24565795cf18748c0f761d Mon Sep 17 00:00:00 2001
From: Robin KAY <komadori@gekkou.co.uk>
Date: Sat, 14 Jan 2023 02:02:14 +0000
Subject: [PATCH] Add render_layers example.

---
 Cargo.toml                |   6 +-
 examples/render_layers.rs | 127 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 132 insertions(+), 1 deletion(-)
 create mode 100644 examples/render_layers.rs

diff --git a/Cargo.toml b/Cargo.toml
index 3c5dae0..4208a66 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -39,9 +39,13 @@ path = "examples/shapes.rs"
 name = "pieces"
 path = "examples/pieces.rs"
 
+[[example]]
+name = "render_layers"
+path = "examples/render_layers.rs"
+
 [[example]]
 name = "animated_fox"
 path = "examples/animated_fox.rs"
 required-features = [
     "bevy/animation", "bevy/bevy_gltf", "bevy/png", "bevy/bevy_scene"
-]
+]
\ No newline at end of file
diff --git a/examples/render_layers.rs b/examples/render_layers.rs
new file mode 100644
index 0000000..71e1d2b
--- /dev/null
+++ b/examples/render_layers.rs
@@ -0,0 +1,127 @@
+use std::f32::consts::PI;
+
+use bevy::{
+    core_pipeline::clear_color::ClearColorConfig,
+    prelude::{shape::Torus, *},
+    render::{camera::Viewport, view::RenderLayers},
+    window::close_on_esc,
+};
+use bevy_mod_outline::{OutlineBundle, OutlinePlugin, OutlineRenderLayers, OutlineVolume};
+
+#[bevy_main]
+fn main() {
+    App::new()
+        .insert_resource(Msaa { samples: 4 })
+        .insert_resource(ClearColor(Color::BLACK))
+        .add_plugins(DefaultPlugins)
+        .add_plugin(OutlinePlugin)
+        .add_startup_system(setup)
+        .add_system(close_on_esc)
+        .add_system(set_camera_viewports)
+        .run();
+}
+
+const OBJECT_LAYER_ID: u8 = 1;
+const OUTLINE_LAYER_ID: u8 = 2;
+
+#[derive(Copy, Clone, Component)]
+struct CameraMode {
+    object_layer: bool,
+    outline_layer: bool,
+}
+
+fn setup(
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+) {
+    // Add torus using the regular surface normals for outlining
+    commands
+        .spawn(PbrBundle {
+            mesh: meshes.add(Mesh::from(Torus {
+                radius: 0.6,
+                ring_radius: 0.2,
+                subdivisions_segments: 40,
+                subdivisions_sides: 20,
+            })),
+            material: materials.add(Color::rgb(0.1, 0.1, 0.9).into()),
+            transform: Transform::from_rotation(Quat::from_rotation_x(0.5 * PI))
+                .with_translation(0.8 * Vec3::Y),
+            ..default()
+        })
+        .insert(OutlineBundle {
+            outline: OutlineVolume {
+                visible: true,
+                colour: Color::WHITE,
+                width: 10.0,
+            },
+            ..default()
+        })
+        .insert(RenderLayers::layer(OBJECT_LAYER_ID))
+        .insert(OutlineRenderLayers(RenderLayers::layer(OUTLINE_LAYER_ID)));
+
+    // Add plane and light source
+    commands.spawn(PbrBundle {
+        mesh: meshes.add(Mesh::from(bevy::prelude::shape::Plane { size: 5.0 })),
+        material: materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
+        ..default()
+    });
+    commands.insert_resource(AmbientLight {
+        color: Color::WHITE,
+        brightness: 1.0,
+    });
+
+    // Add cameras for different combinations of render-layers
+    for i in 0..4 {
+        let object_layer = i & 1 == 1;
+        let outline_layer = (i >> 1) & 1 == 1;
+        let mut layers = RenderLayers::default();
+        if object_layer {
+            layers = layers.with(OBJECT_LAYER_ID);
+        }
+        if outline_layer {
+            layers = layers.with(OUTLINE_LAYER_ID);
+        }
+        commands
+            .spawn(Camera3dBundle {
+                camera: Camera {
+                    priority: i,
+                    ..default()
+                },
+                camera_3d: Camera3d {
+                    clear_color: if i > 0 {
+                        ClearColorConfig::None
+                    } else {
+                        ClearColorConfig::Default
+                    },
+                    ..default()
+                },
+                transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
+                ..default()
+            })
+            .insert(CameraMode {
+                object_layer,
+                outline_layer,
+            })
+            .insert(layers);
+    }
+}
+
+fn set_camera_viewports(windows: Res<Windows>, mut query: Query<(&mut Camera, &CameraMode)>) {
+    if windows.is_changed() {
+        // Divide window into quadrants
+        let win = windows.primary();
+        let size = UVec2::new(win.physical_width() / 2, win.physical_height() / 2);
+        for (mut camera, mode) in query.iter_mut() {
+            let offset = UVec2::new(
+                if mode.object_layer { size.x } else { 0 },
+                if mode.outline_layer { size.y } else { 0 },
+            );
+            camera.viewport = Some(Viewport {
+                physical_position: offset,
+                physical_size: size,
+                ..default()
+            });
+        }
+    }
+}