From bd13dcedddb8203a575d3423273c9e58d565540d Mon Sep 17 00:00:00 2001
From: Robert Swain <robert.swain@gmail.com>
Date: Thu, 8 Jul 2021 04:49:33 +0200
Subject: [PATCH] Directional light and shadow (#6)

Directional light and shadow
---
 Cargo.toml                                    |   4 +
 .../src/components/global_transform.rs        |   2 +-
 .../src/components/transform.rs               |   2 +-
 crates/crevice/src/glam.rs                    |   1 +
 examples/3d/3d_scene_pipelined.rs             |  57 +++-
 examples/3d/cornell_box_pipelined.rs          | 178 +++++++++++++
 pipelined/bevy_pbr2/src/bundle.rs             |  12 +-
 pipelined/bevy_pbr2/src/light.rs              |  77 +++++-
 pipelined/bevy_pbr2/src/render/light.rs       | 247 +++++++++++++++---
 pipelined/bevy_pbr2/src/render/mod.rs         |  46 +++-
 pipelined/bevy_pbr2/src/render/pbr.wgsl       |  77 +++++-
 11 files changed, 638 insertions(+), 65 deletions(-)
 create mode 100644 examples/3d/cornell_box_pipelined.rs

diff --git a/Cargo.toml b/Cargo.toml
index 129a443f1b205..4d9cf45a81f20 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -143,6 +143,10 @@ path = "examples/3d/3d_scene.rs"
 name = "3d_scene_pipelined"
 path = "examples/3d/3d_scene_pipelined.rs"
 
+[[example]]
+name = "cornell_box_pipelined"
+path = "examples/3d/cornell_box_pipelined.rs"
+
 [[example]]
 name = "load_gltf"
 path = "examples/3d/load_gltf.rs"
diff --git a/crates/bevy_transform/src/components/global_transform.rs b/crates/bevy_transform/src/components/global_transform.rs
index ceca829bc74f6..51ec76fbee68a 100644
--- a/crates/bevy_transform/src/components/global_transform.rs
+++ b/crates/bevy_transform/src/components/global_transform.rs
@@ -169,7 +169,7 @@ impl GlobalTransform {
     #[doc(hidden)]
     #[inline]
     pub fn rotate(&mut self, rotation: Quat) {
-        self.rotation *= rotation;
+        self.rotation = rotation * self.rotation;
     }
 
     /// Multiplies `self` with `transform` component by component, returning the
diff --git a/crates/bevy_transform/src/components/transform.rs b/crates/bevy_transform/src/components/transform.rs
index f4a538d30ecb8..43515ed39a908 100644
--- a/crates/bevy_transform/src/components/transform.rs
+++ b/crates/bevy_transform/src/components/transform.rs
@@ -181,7 +181,7 @@ impl Transform {
     /// Rotates the transform by the given rotation.
     #[inline]
     pub fn rotate(&mut self, rotation: Quat) {
-        self.rotation *= rotation;
+        self.rotation = rotation * self.rotation;
     }
 
     /// Multiplies `self` with `transform` component by component, returning the
diff --git a/crates/crevice/src/glam.rs b/crates/crevice/src/glam.rs
index 18fe4cbf677d6..aa57061ffad06 100644
--- a/crates/crevice/src/glam.rs
+++ b/crates/crevice/src/glam.rs
@@ -42,6 +42,7 @@ macro_rules! glam_vectors {
 }
 
 glam_vectors! {
+    glam::UVec4, UVec4, (x, y, z, w),
     glam::Vec2, Vec2, (x, y),
     glam::Vec3, Vec3, (x, y, z),
     glam::Vec4, Vec4, (x, y, z, w),
diff --git a/examples/3d/3d_scene_pipelined.rs b/examples/3d/3d_scene_pipelined.rs
index 97801d9796fbd..b3b37efba0271 100644
--- a/examples/3d/3d_scene_pipelined.rs
+++ b/examples/3d/3d_scene_pipelined.rs
@@ -4,10 +4,13 @@ use bevy::{
     ecs::prelude::*,
     input::Input,
     math::{Quat, Vec3},
-    pbr2::{PbrBundle, PointLight, PointLightBundle, StandardMaterial},
+    pbr2::{
+        AmbientLight, DirectionalLight, DirectionalLightBundle, PbrBundle, PointLight,
+        PointLightBundle, StandardMaterial,
+    },
     prelude::{App, Assets, BuildChildren, KeyCode, Transform},
     render2::{
-        camera::PerspectiveCameraBundle,
+        camera::{OrthographicProjection, PerspectiveCameraBundle},
         color::Color,
         mesh::{shape, Mesh},
     },
@@ -21,6 +24,7 @@ fn main() {
         .add_plugin(LogDiagnosticsPlugin::default())
         .add_startup_system(setup.system())
         .add_system(movement.system())
+        .add_system(animate_light_direction.system())
         .run();
 }
 
@@ -32,11 +36,15 @@ fn setup(
     mut meshes: ResMut<Assets<Mesh>>,
     mut materials: ResMut<Assets<StandardMaterial>>,
 ) {
+    commands.insert_resource(AmbientLight {
+        color: Color::ORANGE_RED,
+        brightness: 0.02,
+    });
     // plane
     commands.spawn_bundle(PbrBundle {
-        mesh: meshes.add(Mesh::from(shape::Plane { size: 5.0 })),
+        mesh: meshes.add(Mesh::from(shape::Plane { size: 10.0 })),
         material: materials.add(StandardMaterial {
-            base_color: Color::INDIGO,
+            base_color: Color::WHITE,
             perceptual_roughness: 1.0,
             ..Default::default()
         }),
@@ -46,7 +54,7 @@ fn setup(
     let mut transform = Transform::from_xyz(2.5, 2.5, 0.0);
     transform.rotate(Quat::from_rotation_z(std::f32::consts::FRAC_PI_2));
     commands.spawn_bundle(PbrBundle {
-        mesh: meshes.add(Mesh::from(shape::Plane { size: 5.0 })),
+        mesh: meshes.add(Mesh::from(shape::Box::new(5.0, 0.15, 5.0))),
         transform,
         material: materials.add(StandardMaterial {
             base_color: Color::INDIGO,
@@ -59,7 +67,7 @@ fn setup(
     let mut transform = Transform::from_xyz(0.0, 2.5, -2.5);
     transform.rotate(Quat::from_rotation_x(std::f32::consts::FRAC_PI_2));
     commands.spawn_bundle(PbrBundle {
-        mesh: meshes.add(Mesh::from(shape::Plane { size: 5.0 })),
+        mesh: meshes.add(Mesh::from(shape::Box::new(5.0, 0.15, 5.0))),
         transform,
         material: materials.add(StandardMaterial {
             base_color: Color::INDIGO,
@@ -76,7 +84,7 @@ fn setup(
                 base_color: Color::PINK,
                 ..Default::default()
             }),
-            transform: Transform::from_xyz(0.0, 1.0, 0.0),
+            transform: Transform::from_xyz(0.0, 0.5, 0.0),
             ..Default::default()
         })
         .insert(Movable);
@@ -174,14 +182,45 @@ fn setup(
             });
         });
 
+    const HALF_SIZE: f32 = 10.0;
+    commands.spawn_bundle(DirectionalLightBundle {
+        directional_light: DirectionalLight {
+            // Configure the projection to better fit the scene
+            shadow_projection: OrthographicProjection {
+                left: -HALF_SIZE,
+                right: HALF_SIZE,
+                bottom: -HALF_SIZE,
+                top: HALF_SIZE,
+                near: -10.0 * HALF_SIZE,
+                far: 10.0 * HALF_SIZE,
+                ..Default::default()
+            },
+            ..Default::default()
+        },
+        transform: Transform {
+            translation: Vec3::new(0.0, 2.0, 0.0),
+            rotation: Quat::from_rotation_x(-1.2),
+            ..Default::default()
+        },
+        ..Default::default()
+    });
+
     // camera
     commands.spawn_bundle(PerspectiveCameraBundle {
-        transform: Transform::from_xyz(-2.0, 5.0, 7.5)
-            .looking_at(Vec3::new(0.0, 2.0, 0.0), Vec3::Y),
+        transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
         ..Default::default()
     });
 }
 
+fn animate_light_direction(
+    time: Res<Time>,
+    mut query: Query<&mut Transform, With<DirectionalLight>>,
+) {
+    for mut transform in query.iter_mut() {
+        transform.rotate(Quat::from_rotation_y(time.delta_seconds() * 0.5));
+    }
+}
+
 fn movement(
     input: Res<Input<KeyCode>>,
     time: Res<Time>,
diff --git a/examples/3d/cornell_box_pipelined.rs b/examples/3d/cornell_box_pipelined.rs
new file mode 100644
index 0000000000000..b30a160b3206f
--- /dev/null
+++ b/examples/3d/cornell_box_pipelined.rs
@@ -0,0 +1,178 @@
+use bevy::{
+    diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
+    ecs::prelude::*,
+    math::{Mat4, Quat, Vec3},
+    pbr2::{
+        AmbientLight, DirectionalLight, DirectionalLightBundle, PbrBundle, PointLight,
+        PointLightBundle, StandardMaterial,
+    },
+    prelude::{App, Assets, BuildChildren, Transform},
+    render2::{
+        camera::{OrthographicProjection, PerspectiveCameraBundle},
+        color::Color,
+        mesh::{shape, Mesh},
+    },
+    PipelinedDefaultPlugins,
+};
+
+fn main() {
+    App::new()
+        .add_plugins(PipelinedDefaultPlugins)
+        .add_plugin(FrameTimeDiagnosticsPlugin::default())
+        .add_plugin(LogDiagnosticsPlugin::default())
+        .add_startup_system(setup.system())
+        .run();
+}
+
+/// set up a simple 3D scene
+fn setup(
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+) {
+    let box_size = 2.0;
+    let box_thickness = 0.15;
+    let box_offset = (box_size + box_thickness) / 2.0;
+
+    // left - red
+    let mut transform = Transform::from_xyz(-box_offset, box_offset, 0.0);
+    transform.rotate(Quat::from_rotation_z(std::f32::consts::FRAC_PI_2));
+    commands.spawn_bundle(PbrBundle {
+        mesh: meshes.add(Mesh::from(shape::Box::new(
+            box_size,
+            box_thickness,
+            box_size,
+        ))),
+        transform,
+        material: materials.add(StandardMaterial {
+            base_color: Color::rgb(0.63, 0.065, 0.05),
+            ..Default::default()
+        }),
+        ..Default::default()
+    });
+    // right - green
+    let mut transform = Transform::from_xyz(box_offset, box_offset, 0.0);
+    transform.rotate(Quat::from_rotation_z(std::f32::consts::FRAC_PI_2));
+    commands.spawn_bundle(PbrBundle {
+        mesh: meshes.add(Mesh::from(shape::Box::new(
+            box_size,
+            box_thickness,
+            box_size,
+        ))),
+        transform,
+        material: materials.add(StandardMaterial {
+            base_color: Color::rgb(0.14, 0.45, 0.091),
+            ..Default::default()
+        }),
+        ..Default::default()
+    });
+    // bottom - white
+    commands.spawn_bundle(PbrBundle {
+        mesh: meshes.add(Mesh::from(shape::Box::new(
+            box_size + 2.0 * box_thickness,
+            box_thickness,
+            box_size,
+        ))),
+        material: materials.add(StandardMaterial {
+            base_color: Color::rgb(0.725, 0.71, 0.68),
+            ..Default::default()
+        }),
+        ..Default::default()
+    });
+    // top - white
+    let transform = Transform::from_xyz(0.0, 2.0 * box_offset, 0.0);
+    commands.spawn_bundle(PbrBundle {
+        mesh: meshes.add(Mesh::from(shape::Box::new(
+            box_size + 2.0 * box_thickness,
+            box_thickness,
+            box_size,
+        ))),
+        transform,
+        material: materials.add(StandardMaterial {
+            base_color: Color::rgb(0.725, 0.71, 0.68),
+            ..Default::default()
+        }),
+        ..Default::default()
+    });
+    // back - white
+    let mut transform = Transform::from_xyz(0.0, box_offset, -box_offset);
+    transform.rotate(Quat::from_rotation_x(std::f32::consts::FRAC_PI_2));
+    commands.spawn_bundle(PbrBundle {
+        mesh: meshes.add(Mesh::from(shape::Box::new(
+            box_size + 2.0 * box_thickness,
+            box_thickness,
+            box_size + 2.0 * box_thickness,
+        ))),
+        transform,
+        material: materials.add(StandardMaterial {
+            base_color: Color::rgb(0.725, 0.71, 0.68),
+            ..Default::default()
+        }),
+        ..Default::default()
+    });
+
+    // ambient light
+    commands.insert_resource(AmbientLight {
+        color: Color::WHITE,
+        brightness: 0.02,
+    });
+    // top light
+    commands
+        .spawn_bundle(PbrBundle {
+            mesh: meshes.add(Mesh::from(shape::Plane { size: 0.4 })),
+            transform: Transform::from_matrix(Mat4::from_scale_rotation_translation(
+                Vec3::ONE,
+                Quat::from_rotation_x(std::f32::consts::PI),
+                Vec3::new(0.0, box_size + 0.5 * box_thickness, 0.0),
+            )),
+            material: materials.add(StandardMaterial {
+                base_color: Color::WHITE,
+                emissive: Color::WHITE * 100.0,
+                ..Default::default()
+            }),
+            ..Default::default()
+        })
+        .with_children(|builder| {
+            builder.spawn_bundle(PointLightBundle {
+                point_light: PointLight {
+                    color: Color::WHITE,
+                    shadow_bias_min: 0.00001,
+                    shadow_bias_max: 0.0001,
+                    intensity: 25.0,
+                    ..Default::default()
+                },
+                transform: Transform::from_translation((box_thickness + 0.05) * Vec3::Y),
+                ..Default::default()
+            });
+        });
+    // directional light
+    const HALF_SIZE: f32 = 10.0;
+    commands
+        .spawn_bundle(DirectionalLightBundle {
+            directional_light: DirectionalLight {
+                illuminance: 10000.0,
+                shadow_bias_min: 0.00001,
+                shadow_bias_max: 0.0001,
+                shadow_projection: OrthographicProjection {
+                    left: -HALF_SIZE,
+                    right: HALF_SIZE,
+                    bottom: -HALF_SIZE,
+                    top: HALF_SIZE,
+                    near: -10.0 * HALF_SIZE,
+                    far: 10.0 * HALF_SIZE,
+                    ..Default::default()
+                },
+                ..Default::default()
+            },
+            transform: Transform::from_rotation(Quat::from_rotation_x(-std::f32::consts::PI / 2.0)),
+            ..Default::default()
+        });
+
+    // camera
+    commands
+        .spawn_bundle(PerspectiveCameraBundle {
+            transform: Transform::from_xyz(0.0, box_offset, 4.0)
+                .looking_at(Vec3::new(0.0, box_offset, 0.0), Vec3::Y),
+            ..Default::default()
+        });
+}
diff --git a/pipelined/bevy_pbr2/src/bundle.rs b/pipelined/bevy_pbr2/src/bundle.rs
index 933384edd6ded..cc7a6b51987d1 100644
--- a/pipelined/bevy_pbr2/src/bundle.rs
+++ b/pipelined/bevy_pbr2/src/bundle.rs
@@ -1,4 +1,4 @@
-use crate::{PointLight, StandardMaterial};
+use crate::{DirectionalLight, PointLight, StandardMaterial};
 use bevy_asset::Handle;
 use bevy_ecs::bundle::Bundle;
 use bevy_render2::mesh::Mesh;
@@ -23,10 +23,18 @@ impl Default for PbrBundle {
     }
 }
 
-/// A component bundle for "light" entities
+/// A component bundle for "point light" entities
 #[derive(Debug, Bundle, Default)]
 pub struct PointLightBundle {
     pub point_light: PointLight,
     pub transform: Transform,
     pub global_transform: GlobalTransform,
 }
+
+/// A component bundle for "directional light" entities
+#[derive(Debug, Bundle, Default)]
+pub struct DirectionalLightBundle {
+    pub directional_light: DirectionalLight,
+    pub transform: Transform,
+    pub global_transform: GlobalTransform,
+}
diff --git a/pipelined/bevy_pbr2/src/light.rs b/pipelined/bevy_pbr2/src/light.rs
index d2451abb8b262..71109c906b4ac 100644
--- a/pipelined/bevy_pbr2/src/light.rs
+++ b/pipelined/bevy_pbr2/src/light.rs
@@ -1,15 +1,14 @@
-use bevy_ecs::reflect::ReflectComponent;
-use bevy_reflect::Reflect;
-use bevy_render2::color::Color;
+use bevy_render2::{camera::OrthographicProjection, color::Color};
 
 /// A light that emits light in all directions from a central point.
-#[derive(Debug, Clone, Copy, Reflect)]
-#[reflect(Component)]
+#[derive(Debug, Clone, Copy)]
 pub struct PointLight {
     pub color: Color,
     pub intensity: f32,
     pub range: f32,
     pub radius: f32,
+    pub shadow_bias_min: f32,
+    pub shadow_bias_max: f32,
 }
 
 impl Default for PointLight {
@@ -19,10 +18,78 @@ impl Default for PointLight {
             intensity: 200.0,
             range: 20.0,
             radius: 0.0,
+            shadow_bias_min: Self::DEFAULT_SHADOW_BIAS_MIN,
+            shadow_bias_max: Self::DEFAULT_SHADOW_BIAS_MAX,
         }
     }
 }
 
+impl PointLight {
+    pub const DEFAULT_SHADOW_BIAS_MIN: f32 = 0.00005;
+    pub const DEFAULT_SHADOW_BIAS_MAX: f32 = 0.002;
+}
+
+/// A Directional light.
+///
+/// Directional lights don't exist in reality but they are a good
+/// approximation for light sources VERY far away, like the sun or
+/// the moon.
+///
+/// Valid values for `illuminance` are:
+///
+/// | Illuminance (lux) | Surfaces illuminated by                        |
+/// |-------------------|------------------------------------------------|
+/// | 0.0001            | Moonless, overcast night sky (starlight)       |
+/// | 0.002             | Moonless clear night sky with airglow          |
+/// | 0.05–0.3          | Full moon on a clear night                     |
+/// | 3.4               | Dark limit of civil twilight under a clear sky |
+/// | 20–50             | Public areas with dark surroundings            |
+/// | 50                | Family living room lights                      |
+/// | 80                | Office building hallway/toilet lighting        |
+/// | 100               | Very dark overcast day                         |
+/// | 150               | Train station platforms                        |
+/// | 320–500           | Office lighting                                |
+/// | 400               | Sunrise or sunset on a clear day.              |
+/// | 1000              | Overcast day; typical TV studio lighting       |
+/// | 10,000–25,000     | Full daylight (not direct sun)                 |
+/// | 32,000–100,000    | Direct sunlight                                |
+///
+/// Source: [Wikipedia](https://en.wikipedia.org/wiki/Lux)
+#[derive(Debug, Clone)]
+pub struct DirectionalLight {
+    pub color: Color,
+    pub illuminance: f32,
+    pub shadow_projection: OrthographicProjection,
+    pub shadow_bias_min: f32,
+    pub shadow_bias_max: f32,
+}
+
+impl Default for DirectionalLight {
+    fn default() -> Self {
+        let size = 100.0;
+        DirectionalLight {
+            color: Color::rgb(1.0, 1.0, 1.0),
+            illuminance: 100000.0,
+            shadow_projection: OrthographicProjection {
+                left: -size,
+                right: size,
+                bottom: -size,
+                top: size,
+                near: -size,
+                far: size,
+                ..Default::default()
+            },
+            shadow_bias_min: Self::DEFAULT_SHADOW_BIAS_MIN,
+            shadow_bias_max: Self::DEFAULT_SHADOW_BIAS_MAX,
+        }
+    }
+}
+
+impl DirectionalLight {
+    pub const DEFAULT_SHADOW_BIAS_MIN: f32 = 0.00005;
+    pub const DEFAULT_SHADOW_BIAS_MAX: f32 = 0.002;
+}
+
 // Ambient light color.
 #[derive(Debug)]
 pub struct AmbientLight {
diff --git a/pipelined/bevy_pbr2/src/render/light.rs b/pipelined/bevy_pbr2/src/render/light.rs
index e25686d97bdae..6328339a9b931 100644
--- a/pipelined/bevy_pbr2/src/render/light.rs
+++ b/pipelined/bevy_pbr2/src/render/light.rs
@@ -1,7 +1,8 @@
-use crate::{AmbientLight, ExtractedMeshes, MeshMeta, PbrShaders, PointLight};
+use crate::{AmbientLight, DirectionalLight, ExtractedMeshes, MeshMeta, PbrShaders, PointLight};
 use bevy_ecs::{prelude::*, system::SystemState};
 use bevy_math::{const_vec3, Mat4, Vec3, Vec4};
 use bevy_render2::{
+    camera::CameraProjection,
     color::Color,
     core_pipeline::Transparent3dPhase,
     mesh::Mesh,
@@ -28,11 +29,22 @@ pub struct ExtractedPointLight {
     range: f32,
     radius: f32,
     transform: GlobalTransform,
+    shadow_bias_min: f32,
+    shadow_bias_max: f32,
+}
+
+pub struct ExtractedDirectionalLight {
+    color: Color,
+    illuminance: f32,
+    direction: Vec3,
+    projection: Mat4,
+    shadow_bias_min: f32,
+    shadow_bias_max: f32,
 }
 
 #[repr(C)]
 #[derive(Copy, Clone, AsStd140, Default, Debug)]
-pub struct GpuLight {
+pub struct GpuPointLight {
     color: Vec4,
     // proj: Mat4,
     position: Vec3,
@@ -40,30 +52,51 @@ pub struct GpuLight {
     radius: f32,
     near: f32,
     far: f32,
+    shadow_bias_min: f32,
+    shadow_bias_max: f32,
+}
+
+#[repr(C)]
+#[derive(Copy, Clone, AsStd140, Default, Debug)]
+pub struct GpuDirectionalLight {
+    view_projection: Mat4,
+    color: Vec4,
+    dir_to_light: Vec3,
+    shadow_bias_min: f32,
+    shadow_bias_max: f32,
 }
 
 #[repr(C)]
 #[derive(Copy, Clone, Debug, AsStd140)]
 pub struct GpuLights {
     // TODO: this comes first to work around a WGSL alignment issue. We need to solve this issue before releasing the renderer rework
-    lights: [GpuLight; MAX_POINT_LIGHTS],
+    point_lights: [GpuPointLight; MAX_POINT_LIGHTS],
+    directional_lights: [GpuDirectionalLight; MAX_DIRECTIONAL_LIGHTS],
     ambient_color: Vec4,
-    len: u32,
+    n_point_lights: u32,
+    n_directional_lights: u32,
 }
 
-// NOTE: this must be kept in sync MAX_POINT_LIGHTS in pbr.frag
+// NOTE: this must be kept in sync with the same constants in pbr.frag
 pub const MAX_POINT_LIGHTS: usize = 10;
-pub const SHADOW_SIZE: Extent3d = Extent3d {
+pub const MAX_DIRECTIONAL_LIGHTS: usize = 1;
+pub const POINT_SHADOW_SIZE: Extent3d = Extent3d {
     width: 1024,
     height: 1024,
-    depth_or_array_layers: 6 * MAX_POINT_LIGHTS as u32,
+    depth_or_array_layers: (6 * MAX_POINT_LIGHTS) as u32,
+};
+pub const DIRECTIONAL_SHADOW_SIZE: Extent3d = Extent3d {
+    width: 4096,
+    height: 4096,
+    depth_or_array_layers: MAX_DIRECTIONAL_LIGHTS as u32,
 };
 pub const SHADOW_FORMAT: TextureFormat = TextureFormat::Depth32Float;
 
 pub struct ShadowShaders {
     pub pipeline: RenderPipeline,
     pub view_layout: BindGroupLayout,
-    pub light_sampler: Sampler,
+    pub point_light_sampler: Sampler,
+    pub directional_light_sampler: Sampler,
 }
 
 // TODO: this pattern for initializing the shaders / pipeline isn't ideal. this should be handled by the asset system
@@ -160,7 +193,17 @@ impl FromWorld for ShadowShaders {
         ShadowShaders {
             pipeline,
             view_layout,
-            light_sampler: render_device.create_sampler(&SamplerDescriptor {
+            point_light_sampler: render_device.create_sampler(&SamplerDescriptor {
+                address_mode_u: AddressMode::ClampToEdge,
+                address_mode_v: AddressMode::ClampToEdge,
+                address_mode_w: AddressMode::ClampToEdge,
+                mag_filter: FilterMode::Linear,
+                min_filter: FilterMode::Linear,
+                mipmap_filter: FilterMode::Nearest,
+                compare: Some(CompareFunction::LessEqual),
+                ..Default::default()
+            }),
+            directional_light_sampler: render_device.create_sampler(&SamplerDescriptor {
                 address_mode_u: AddressMode::ClampToEdge,
                 address_mode_v: AddressMode::ClampToEdge,
                 address_mode_w: AddressMode::ClampToEdge,
@@ -178,21 +221,36 @@ impl FromWorld for ShadowShaders {
 pub fn extract_lights(
     mut commands: Commands,
     ambient_light: Res<AmbientLight>,
-    lights: Query<(Entity, &PointLight, &GlobalTransform)>,
+    point_lights: Query<(Entity, &PointLight, &GlobalTransform)>,
+    directional_lights: Query<(Entity, &DirectionalLight, &GlobalTransform)>,
 ) {
     commands.insert_resource(ExtractedAmbientLight {
         color: ambient_light.color,
         brightness: ambient_light.brightness,
     });
-    for (entity, light, transform) in lights.iter() {
+    for (entity, point_light, transform) in point_lights.iter() {
         commands.get_or_spawn(entity).insert(ExtractedPointLight {
-            color: light.color,
-            intensity: light.intensity,
-            range: light.range,
-            radius: light.radius,
+            color: point_light.color,
+            intensity: point_light.intensity,
+            range: point_light.range,
+            radius: point_light.radius,
             transform: *transform,
+            shadow_bias_min: point_light.shadow_bias_min,
+            shadow_bias_max: point_light.shadow_bias_max,
         });
     }
+    for (entity, directional_light, transform) in directional_lights.iter() {
+        commands
+            .get_or_spawn(entity)
+            .insert(ExtractedDirectionalLight {
+                color: directional_light.color,
+                illuminance: directional_light.illuminance,
+                direction: transform.forward(),
+                projection: directional_light.shadow_projection.get_projection_matrix(),
+                shadow_bias_min: directional_light.shadow_bias_min,
+                shadow_bias_max: directional_light.shadow_bias_max,
+            });
+    }
 }
 
 // Can't do `Vec3::Y * -1.0` because mul isn't const
@@ -239,13 +297,28 @@ const CUBE_MAP_FACES: [CubeMapFace; 6] = [
     },
 ];
 
+fn face_index_to_name(face_index: usize) -> &'static str {
+    match face_index {
+        0 => "+x",
+        1 => "-x",
+        2 => "+y",
+        3 => "-y",
+        4 => "+z",
+        5 => "-z",
+        _ => "invalid",
+    }
+}
+
 pub struct ViewLight {
     pub depth_texture_view: TextureView,
+    pub pass_name: String,
 }
 
 pub struct ViewLights {
-    pub light_depth_texture: Texture,
-    pub light_depth_texture_view: TextureView,
+    pub point_light_depth_texture: Texture,
+    pub point_light_depth_texture_view: TextureView,
+    pub directional_light_depth_texture: Texture,
+    pub directional_light_depth_texture_view: TextureView,
     pub lights: Vec<Entity>,
     pub gpu_light_binding_index: u32,
 }
@@ -263,7 +336,8 @@ pub fn prepare_lights(
     mut light_meta: ResMut<LightMeta>,
     views: Query<Entity, With<RenderPhase<Transparent3dPhase>>>,
     ambient_light: Res<ExtractedAmbientLight>,
-    lights: Query<&ExtractedPointLight>,
+    point_lights: Query<&ExtractedPointLight>,
+    directional_lights: Query<&ExtractedDirectionalLight>,
 ) {
     // PERF: view.iter().count() could be views.iter().len() if we implemented ExactSizeIterator for archetype-only filters
     light_meta
@@ -273,10 +347,22 @@ pub fn prepare_lights(
     let ambient_color = ambient_light.color.as_rgba_linear() * ambient_light.brightness;
     // set up light data for each view
     for entity in views.iter() {
-        let light_depth_texture = texture_cache.get(
+        let point_light_depth_texture = texture_cache.get(
+            &render_device,
+            TextureDescriptor {
+                size: POINT_SHADOW_SIZE,
+                mip_level_count: 1,
+                sample_count: 1,
+                dimension: TextureDimension::D2,
+                format: SHADOW_FORMAT,
+                usage: TextureUsage::RENDER_ATTACHMENT | TextureUsage::SAMPLED,
+                label: None,
+            },
+        );
+        let directional_light_depth_texture = texture_cache.get(
             &render_device,
             TextureDescriptor {
-                size: SHADOW_SIZE,
+                size: DIRECTIONAL_SHADOW_SIZE,
                 mip_level_count: 1,
                 sample_count: 1,
                 dimension: TextureDimension::D2,
@@ -289,12 +375,14 @@ pub fn prepare_lights(
 
         let mut gpu_lights = GpuLights {
             ambient_color: ambient_color.into(),
-            len: lights.iter().len() as u32,
-            lights: [GpuLight::default(); MAX_POINT_LIGHTS],
+            n_point_lights: point_lights.iter().len() as u32,
+            n_directional_lights: directional_lights.iter().len() as u32,
+            point_lights: [GpuPointLight::default(); MAX_POINT_LIGHTS],
+            directional_lights: [GpuDirectionalLight::default(); MAX_DIRECTIONAL_LIGHTS],
         };
 
         // TODO: this should select lights based on relevance to the view instead of the first ones that show up in a query
-        for (light_index, light) in lights.iter().enumerate().take(MAX_POINT_LIGHTS) {
+        for (light_index, light) in point_lights.iter().enumerate().take(MAX_POINT_LIGHTS) {
             let projection =
                 Mat4::perspective_rh(std::f32::consts::FRAC_PI_2, 1.0, 0.1, light.range);
 
@@ -308,7 +396,7 @@ pub fn prepare_lights(
                 let view_rotation = GlobalTransform::identity().looking_at(*target, *up);
 
                 let depth_texture_view =
-                    light_depth_texture
+                    point_light_depth_texture
                         .texture
                         .create_view(&TextureViewDescriptor {
                             label: None,
@@ -324,10 +412,17 @@ pub fn prepare_lights(
                 let view_light_entity = commands
                     .spawn()
                     .insert_bundle((
-                        ViewLight { depth_texture_view },
+                        ViewLight {
+                            depth_texture_view,
+                            pass_name: format!(
+                                "shadow pass point light {} {}",
+                                light_index,
+                                face_index_to_name(face_index)
+                            ),
+                        },
                         ExtractedView {
-                            width: SHADOW_SIZE.width,
-                            height: SHADOW_SIZE.height,
+                            width: POINT_SHADOW_SIZE.width,
+                            height: POINT_SHADOW_SIZE.height,
                             transform: view_translation * view_rotation,
                             projection,
                         },
@@ -337,7 +432,7 @@ pub fn prepare_lights(
                 view_lights.push(view_light_entity);
             }
 
-            gpu_lights.lights[light_index] = GpuLight {
+            gpu_lights.point_lights[light_index] = GpuPointLight {
                 // premultiply color by intensity
                 // we don't use the alpha at all, so no reason to multiply only [0..3]
                 color: (light.color.as_rgba_linear() * light.intensity).into(),
@@ -347,11 +442,83 @@ pub fn prepare_lights(
                 near: 0.1,
                 far: light.range,
                 // proj: projection,
+                shadow_bias_min: light.shadow_bias_min,
+                shadow_bias_max: light.shadow_bias_max,
             };
         }
 
-        let light_depth_texture_view =
-            light_depth_texture
+        for (i, light) in directional_lights
+            .iter()
+            .enumerate()
+            .take(MAX_DIRECTIONAL_LIGHTS)
+        {
+            // direction is negated to be ready for N.L
+            let dir_to_light = -light.direction;
+
+            // convert from illuminance (lux) to candelas
+            //
+            // exposure is hard coded at the moment but should be replaced
+            // by values coming from the camera
+            // see: https://google.github.io/filament/Filament.html#imagingpipeline/physicallybasedcamera/exposuresettings
+            const APERTURE: f32 = 4.0;
+            const SHUTTER_SPEED: f32 = 1.0 / 250.0;
+            const SENSITIVITY: f32 = 100.0;
+            let ev100 =
+                f32::log2(APERTURE * APERTURE / SHUTTER_SPEED) - f32::log2(SENSITIVITY / 100.0);
+            let exposure = 1.0 / (f32::powf(2.0, ev100) * 1.2);
+            let intensity = light.illuminance * exposure;
+
+            // NOTE: A directional light seems to have to have an eye position on the line along the direction of the light
+            //       through the world origin. I (Rob Swain) do not yet understand why it cannot be translated away from this.
+            let view = Mat4::look_at_rh(Vec3::ZERO, light.direction, Vec3::Y);
+            // NOTE: This orthographic projection defines the volume within which shadows from a directional light can be cast
+            let projection = light.projection;
+
+            gpu_lights.directional_lights[i] = GpuDirectionalLight {
+                // premultiply color by intensity
+                // we don't use the alpha at all, so no reason to multiply only [0..3]
+                color: (light.color.as_rgba_linear() * intensity).into(),
+                dir_to_light,
+                // NOTE: * view is correct, it should not be view.inverse() here
+                view_projection: projection * view,
+                shadow_bias_min: light.shadow_bias_min,
+                shadow_bias_max: light.shadow_bias_max,
+            };
+
+            let depth_texture_view =
+                directional_light_depth_texture
+                    .texture
+                    .create_view(&TextureViewDescriptor {
+                        label: None,
+                        format: None,
+                        dimension: Some(TextureViewDimension::D2),
+                        aspect: TextureAspect::All,
+                        base_mip_level: 0,
+                        mip_level_count: None,
+                        base_array_layer: i as u32,
+                        array_layer_count: NonZeroU32::new(1),
+                    });
+
+            let view_light_entity = commands
+                .spawn()
+                .insert_bundle((
+                    ViewLight {
+                        depth_texture_view,
+                        pass_name: format!("shadow pass directional light {}", i),
+                    },
+                    ExtractedView {
+                        width: DIRECTIONAL_SHADOW_SIZE.width,
+                        height: DIRECTIONAL_SHADOW_SIZE.height,
+                        transform: GlobalTransform::from_matrix(view.inverse()),
+                        projection,
+                    },
+                    RenderPhase::<ShadowPhase>::default(),
+                ))
+                .id();
+            view_lights.push(view_light_entity);
+        }
+        let point_light_depth_texture_view =
+            point_light_depth_texture
                 .texture
                 .create_view(&TextureViewDescriptor {
                     label: None,
@@ -363,10 +530,24 @@ pub fn prepare_lights(
                     base_array_layer: 0,
                     array_layer_count: None,
                 });
+        let directional_light_depth_texture_view = directional_light_depth_texture
+            .texture
+            .create_view(&TextureViewDescriptor {
+                label: None,
+                format: None,
+                dimension: Some(TextureViewDimension::D2Array),
+                aspect: TextureAspect::All,
+                base_mip_level: 0,
+                mip_level_count: None,
+                base_array_layer: 0,
+                array_layer_count: None,
+            });
 
         commands.entity(entity).insert(ViewLights {
-            light_depth_texture: light_depth_texture.texture,
-            light_depth_texture_view,
+            point_light_depth_texture: point_light_depth_texture.texture,
+            point_light_depth_texture_view,
+            directional_light_depth_texture: directional_light_depth_texture.texture,
+            directional_light_depth_texture_view,
             lights: view_lights,
             gpu_light_binding_index: light_meta.view_gpu_lights.push(gpu_lights),
         });
@@ -419,7 +600,7 @@ impl Node for ShadowPassNode {
                     .get_manual(world, view_light_entity)
                     .unwrap();
                 let pass_descriptor = RenderPassDescriptor {
-                    label: Some("shadow_pass"),
+                    label: Some(&view_light.pass_name),
                     color_attachments: &[],
                     depth_stencil_attachment: Some(RenderPassDepthStencilAttachment {
                         view: &view_light.depth_texture_view,
diff --git a/pipelined/bevy_pbr2/src/render/mod.rs b/pipelined/bevy_pbr2/src/render/mod.rs
index 9494ee2a614a8..94d9f1507554d 100644
--- a/pipelined/bevy_pbr2/src/render/mod.rs
+++ b/pipelined/bevy_pbr2/src/render/mod.rs
@@ -66,13 +66,13 @@ impl FromWorld for PbrShaders {
                     ty: BindingType::Buffer {
                         ty: BufferBindingType::Uniform,
                         has_dynamic_offset: true,
-                        // TODO: change this to ViewUniform::std140_size_static once crevice fixes this!
+                        // TODO: change this to GpuLights::std140_size_static once crevice fixes this!
                         // Context: https://github.com/LPGhatguy/crevice/issues/29
-                        min_binding_size: BufferSize::new(512),
+                        min_binding_size: BufferSize::new(1024),
                     },
                     count: None,
                 },
-                // Shadow Texture Array
+                // Point Shadow Texture Cube Array
                 BindGroupLayoutEntry {
                     binding: 2,
                     visibility: ShaderStage::FRAGMENT,
@@ -83,7 +83,7 @@ impl FromWorld for PbrShaders {
                     },
                     count: None,
                 },
-                // Shadow Texture Array Sampler
+                // Point Shadow Texture Array Sampler
                 BindGroupLayoutEntry {
                     binding: 3,
                     visibility: ShaderStage::FRAGMENT,
@@ -93,6 +93,27 @@ impl FromWorld for PbrShaders {
                     },
                     count: None,
                 },
+                // Directional Shadow Texture Array
+                BindGroupLayoutEntry {
+                    binding: 4,
+                    visibility: ShaderStage::FRAGMENT,
+                    ty: BindingType::Texture {
+                        multisampled: false,
+                        sample_type: TextureSampleType::Depth,
+                        view_dimension: TextureViewDimension::D2Array,
+                    },
+                    count: None,
+                },
+                // Directional Shadow Texture Array Sampler
+                BindGroupLayoutEntry {
+                    binding: 5,
+                    visibility: ShaderStage::FRAGMENT,
+                    ty: BindingType::Sampler {
+                        comparison: true,
+                        filtering: true,
+                    },
+                    count: None,
+                },
             ],
             label: None,
         });
@@ -379,7 +400,6 @@ pub fn extract_meshes(
                     continue;
                 }
             }
-
             if let Some(ref image) = material.emissive_texture {
                 if !images.contains(image) {
                     continue;
@@ -537,11 +557,23 @@ pub fn queue_meshes(
                 },
                 BindGroupEntry {
                     binding: 2,
-                    resource: BindingResource::TextureView(&view_lights.light_depth_texture_view),
+                    resource: BindingResource::TextureView(
+                        &view_lights.point_light_depth_texture_view,
+                    ),
                 },
                 BindGroupEntry {
                     binding: 3,
-                    resource: BindingResource::Sampler(&shadow_shaders.light_sampler),
+                    resource: BindingResource::Sampler(&shadow_shaders.point_light_sampler),
+                },
+                BindGroupEntry {
+                    binding: 4,
+                    resource: BindingResource::TextureView(
+                        &view_lights.directional_light_depth_texture_view,
+                    ),
+                },
+                BindGroupEntry {
+                    binding: 5,
+                    resource: BindingResource::Sampler(&shadow_shaders.directional_light_sampler),
                 },
             ],
             label: None,
diff --git a/pipelined/bevy_pbr2/src/render/pbr.wgsl b/pipelined/bevy_pbr2/src/render/pbr.wgsl
index fa2f555db6dbe..3bc711fb06a3a 100644
--- a/pipelined/bevy_pbr2/src/render/pbr.wgsl
+++ b/pipelined/bevy_pbr2/src/render/pbr.wgsl
@@ -95,6 +95,16 @@ struct PointLight {
     radius: f32;
     near: f32;
     far: f32;
+    shadow_bias_min: f32;
+    shadow_bias_max: f32;
+};
+
+struct DirectionalLight {
+    view_projection: mat4x4<f32>;
+    color: vec4<f32>;
+    direction_to_light: vec3<f32>;
+    shadow_bias_min: f32;
+    shadow_bias_max: f32;
 };
 
 [[block]]
@@ -102,8 +112,10 @@ struct Lights {
     // NOTE: this array size must be kept in sync with the constants defined bevy_pbr2/src/render/light.rs
     // TODO: this can be removed if we move to storage buffers for light arrays
     point_lights: array<PointLight, 10>;
+    directional_lights: array<DirectionalLight, 1>;
     ambient_color: vec4<f32>;
-    num_lights: u32;
+    n_point_lights: u32;
+    n_directional_lights: u32;
 };
 
 let FLAGS_BASE_COLOR_TEXTURE_BIT: u32         = 1u;
@@ -117,9 +129,13 @@ let FLAGS_UNLIT_BIT: u32                      = 32u;
 [[group(0), binding(1)]]
 var lights: Lights;
 [[group(0), binding(2)]]
-var shadow_textures: texture_depth_cube_array;
+var point_shadow_textures: texture_depth_cube_array;
 [[group(0), binding(3)]]
-var shadow_textures_sampler: sampler_comparison;
+var point_shadow_textures_sampler: sampler_comparison;
+[[group(0), binding(4)]]
+var directional_shadow_textures: texture_depth_2d_array;
+[[group(0), binding(5)]]
+var directional_shadow_textures_sampler: sampler_comparison;
 
 [[group(2), binding(0)]]
 var material: StandardMaterial;
@@ -348,7 +364,22 @@ fn point_light(
     return ((diffuse + specular_light) * light.color.rgb) * (rangeAttenuation * NoL);
 }
 
-fn fetch_shadow(light_id: i32, frag_position: vec4<f32>) -> f32 {
+fn directional_light(light: DirectionalLight, roughness: f32, NdotV: f32, normal: vec3<f32>, view: vec3<f32>, R: vec3<f32>, F0: vec3<f32>, diffuseColor: vec3<f32>) -> vec3<f32> {
+    let incident_light = light.direction_to_light.xyz;
+
+    let half_vector = normalize(incident_light + view);
+    let NoL = saturate(dot(normal, incident_light));
+    let NoH = saturate(dot(normal, half_vector));
+    let LoH = saturate(dot(incident_light, half_vector));
+
+    let diffuse = diffuseColor * Fd_Burley(roughness, NdotV, NoL, LoH);
+    let specularIntensity = 1.0;
+    let specular_light = specular(F0, roughness, half_vector, NdotV, NoL, NoH, LoH, specularIntensity);
+
+    return (specular_light + diffuse) * light.color.rgb * NoL;
+}
+
+fn fetch_point_shadow(light_id: i32, frag_position: vec4<f32>, shadow_bias: f32) -> f32 {
     let light = lights.point_lights[light_id];
 
     // because the shadow maps align with the axes and the frustum planes are at 45 degrees
@@ -382,7 +413,22 @@ fn fetch_shadow(light_id: i32, frag_position: vec4<f32>) -> f32 {
     //       mip-mapping functionality. The shadow maps have no mipmaps so Level just samples
     //       from LOD 0.
     let bias = 0.0001;
-    return textureSampleCompareLevel(shadow_textures, shadow_textures_sampler, frag_ls, i32(light_id), depth - bias);
+    return textureSampleCompareLevel(point_shadow_textures, point_shadow_textures_sampler, frag_ls, i32(light_id), depth - shadow_bias);
+}
+
+fn fetch_directional_shadow(light_id: i32, homogeneous_coords: vec4<f32>, shadow_bias: f32) -> f32 {
+    if (homogeneous_coords.w <= 0.0) {
+        return 1.0;
+    }
+    // compensate for the Y-flip difference between the NDC and texture coordinates
+    let flip_correction = vec2<f32>(0.5, -0.5);
+    let proj_correction = 1.0 / homogeneous_coords.w;
+    // compute texture coordinates for shadow lookup
+    let light_local = homogeneous_coords.xy * flip_correction * proj_correction + vec2<f32>(0.5, 0.5);
+    // do the lookup, using HW PCF and comparison
+    // NOTE: Due to non-uniform control flow above, we must use the level variant of the texture
+    //       sampler to avoid use of implicit derivatives causing possible undefined behavior.
+    return textureSampleCompareLevel(directional_shadow_textures, directional_shadow_textures_sampler, light_local, i32(light_id), homogeneous_coords.z * proj_correction - shadow_bias);
 }
 
 struct FragmentInput {
@@ -471,10 +517,27 @@ fn fragment(in: FragmentInput) -> [[location(0)]] vec4<f32> {
 
         // accumulate color
         var light_accum: vec3<f32> = vec3<f32>(0.0);
-        for (var i: i32 = 0; i < i32(lights.num_lights); i = i + 1) {
+        let n_point_lights = i32(lights.n_point_lights);
+        let n_directional_lights = i32(lights.n_directional_lights);
+        for (var i: i32 = 0; i < n_point_lights; i = i + 1) {
             let light = lights.point_lights[i];
             let light_contrib = point_light(in.world_position.xyz, light, roughness, NdotV, N, V, R, F0, diffuse_color);
-            let shadow = fetch_shadow(i, in.world_position);
+            let dir_to_light = normalize(light.position.xyz - in.world_position.xyz);
+            let shadow_bias = max(
+                light.shadow_bias_max * (1.0 - dot(in.world_normal, dir_to_light)),
+                light.shadow_bias_min
+            );
+            let shadow = fetch_point_shadow(i, in.world_position, shadow_bias);
+            light_accum = light_accum + light_contrib * shadow;
+        }
+        for (var i: i32 = 0; i < n_directional_lights; i = i + 1) {
+            let light = lights.directional_lights[i];
+            let light_contrib = directional_light(light, roughness, NdotV, N, V, R, F0, diffuse_color);
+            let shadow_bias = max(
+                light.shadow_bias_max * (1.0 - dot(in.world_normal, light.direction_to_light.xyz)),
+                light.shadow_bias_min
+            );
+            let shadow = fetch_directional_shadow(i, light.view_projection * in.world_position, shadow_bias);
             light_accum = light_accum + light_contrib * shadow;
         }