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bevy_pbr2: Add support for configurable shadow map sizes (#2700)
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# Objective

Add support for configurable shadow map sizes

## Solution

- Add `DirectionalLightShadowMap` and `PointLightShadowMap` resources, which just have size members, to the app world, and add `Extracted*` counterparts to the render world
- Use the configured sizes when rendering shadow maps
- Default sizes remain the same - 4096 for directional light shadow maps, 1024 for point light shadow maps (which are cube maps so 6 faces at 1024x1024 per light)
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@superdump
superdump committed Aug 25, 2021
1 parent 9898469 commit f368bf7
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Showing 3 changed files with 60 additions and 20 deletions.
4 changes: 3 additions & 1 deletion pipelined/bevy_pbr2/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,9 @@ pub struct PbrPlugin;
impl Plugin for PbrPlugin {
fn build(&self, app: &mut App) {
app.add_plugin(StandardMaterialPlugin)
.init_resource::<AmbientLight>();
.init_resource::<AmbientLight>()
.init_resource::<DirectionalLightShadowMap>()
.init_resource::<PointLightShadowMap>();

let render_app = app.sub_app(RenderApp);
render_app
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22 changes: 22 additions & 0 deletions pipelined/bevy_pbr2/src/light.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,17 @@ impl PointLight {
pub const DEFAULT_SHADOW_NORMAL_BIAS: f32 = 0.5;
}

#[derive(Clone, Debug)]
pub struct PointLightShadowMap {
pub size: usize,
}

impl Default for PointLightShadowMap {
fn default() -> Self {
Self { size: 1024 }
}
}

/// A Directional light.
///
/// Directional lights don't exist in reality but they are a good
Expand Down Expand Up @@ -113,6 +124,17 @@ impl DirectionalLight {
pub const DEFAULT_SHADOW_NORMAL_BIAS: f32 = 0.6;
}

#[derive(Clone, Debug)]
pub struct DirectionalLightShadowMap {
pub size: usize,
}

impl Default for DirectionalLightShadowMap {
fn default() -> Self {
Self { size: 4096 }
}
}

/// Ambient light.
#[derive(Debug)]
pub struct AmbientLight {
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54 changes: 35 additions & 19 deletions pipelined/bevy_pbr2/src/render/light.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,7 @@
use crate::{AmbientLight, DirectionalLight, ExtractedMeshes, MeshMeta, PbrShaders, PointLight};
use crate::{
AmbientLight, DirectionalLight, DirectionalLightShadowMap, ExtractedMeshes, MeshMeta,
PbrShaders, PointLight, PointLightShadowMap,
};
use bevy_core_pipeline::Transparent3dPhase;
use bevy_ecs::{prelude::*, system::SystemState};
use bevy_math::{const_vec3, Mat4, Vec3, Vec4};
Expand Down Expand Up @@ -34,6 +37,8 @@ pub struct ExtractedPointLight {
shadow_normal_bias: f32,
}

pub type ExtractedPointLightShadowMap = PointLightShadowMap;

pub struct ExtractedDirectionalLight {
color: Color,
illuminance: f32,
Expand All @@ -43,6 +48,8 @@ pub struct ExtractedDirectionalLight {
shadow_normal_bias: f32,
}

pub type ExtractedDirectionalLightShadowMap = DirectionalLightShadowMap;

#[repr(C)]
#[derive(Copy, Clone, AsStd140, Default, Debug)]
pub struct GpuPointLight {
Expand Down Expand Up @@ -81,16 +88,8 @@ pub struct GpuLights {
// NOTE: this must be kept in sync with the same constants in pbr.frag
pub const MAX_POINT_LIGHTS: usize = 10;
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,
};
pub const DIRECTIONAL_SHADOW_SIZE: Extent3d = Extent3d {
width: 4096,
height: 4096,
depth_or_array_layers: MAX_DIRECTIONAL_LIGHTS as u32,
};
pub const POINT_SHADOW_LAYERS: u32 = (6 * MAX_POINT_LIGHTS) as u32;
pub const DIRECTIONAL_SHADOW_LAYERS: u32 = MAX_DIRECTIONAL_LIGHTS as u32;
pub const SHADOW_FORMAT: TextureFormat = TextureFormat::Depth32Float;

pub struct ShadowShaders {
Expand Down Expand Up @@ -222,21 +221,27 @@ impl FromWorld for ShadowShaders {
pub fn extract_lights(
mut commands: Commands,
ambient_light: Res<AmbientLight>,
point_light_shadow_map: Res<PointLightShadowMap>,
directional_light_shadow_map: Res<DirectionalLightShadowMap>,
point_lights: Query<(Entity, &PointLight, &GlobalTransform)>,
directional_lights: Query<(Entity, &DirectionalLight, &GlobalTransform)>,
) {
commands.insert_resource(ExtractedAmbientLight {
color: ambient_light.color,
brightness: ambient_light.brightness,
});
commands.insert_resource::<ExtractedPointLightShadowMap>(point_light_shadow_map.clone());
commands.insert_resource::<ExtractedDirectionalLightShadowMap>(
directional_light_shadow_map.clone(),
);
// This is the point light shadow map texel size for one face of the cube as a distance of 1.0
// world unit from the light.
// point_light_texel_size = 2.0 * 1.0 * tan(PI / 4.0) / cube face width in texels
// PI / 4.0 is half the cube face fov, tan(PI / 4.0) = 1.0, so this simplifies to:
// point_light_texel_size = 2.0 / cube face width in texels
// NOTE: When using various PCF kernel sizes, this will need to be adjusted, according to:
// https://catlikecoding.com/unity/tutorials/custom-srp/point-and-spot-shadows/
let point_light_texel_size = 2.0 / POINT_SHADOW_SIZE.width as f32;
let point_light_texel_size = 2.0 / point_light_shadow_map.size as f32;
for (entity, point_light, transform) in point_lights.iter() {
commands.get_or_spawn(entity).insert(ExtractedPointLight {
color: point_light.color,
Expand Down Expand Up @@ -265,7 +270,8 @@ pub fn extract_lights(
directional_light.shadow_projection.top
- directional_light.shadow_projection.bottom,
);
let directional_light_texel_size = largest_dimension / DIRECTIONAL_SHADOW_SIZE.width as f32;
let directional_light_texel_size =
largest_dimension / directional_light_shadow_map.size as f32;
commands
.get_or_spawn(entity)
.insert(ExtractedDirectionalLight {
Expand Down Expand Up @@ -366,6 +372,8 @@ pub fn prepare_lights(
mut light_meta: ResMut<LightMeta>,
views: Query<Entity, With<RenderPhase<Transparent3dPhase>>>,
ambient_light: Res<ExtractedAmbientLight>,
point_light_shadow_map: Res<ExtractedPointLightShadowMap>,
directional_light_shadow_map: Res<ExtractedDirectionalLightShadowMap>,
point_lights: Query<&ExtractedPointLight>,
directional_lights: Query<&ExtractedDirectionalLight>,
) {
Expand All @@ -380,7 +388,11 @@ pub fn prepare_lights(
let point_light_depth_texture = texture_cache.get(
&render_device,
TextureDescriptor {
size: POINT_SHADOW_SIZE,
size: Extent3d {
width: point_light_shadow_map.size as u32,
height: point_light_shadow_map.size as u32,
depth_or_array_layers: POINT_SHADOW_LAYERS,
},
mip_level_count: 1,
sample_count: 1,
dimension: TextureDimension::D2,
Expand All @@ -392,7 +404,11 @@ pub fn prepare_lights(
let directional_light_depth_texture = texture_cache.get(
&render_device,
TextureDescriptor {
size: DIRECTIONAL_SHADOW_SIZE,
size: Extent3d {
width: directional_light_shadow_map.size as u32,
height: directional_light_shadow_map.size as u32,
depth_or_array_layers: DIRECTIONAL_SHADOW_LAYERS,
},
mip_level_count: 1,
sample_count: 1,
dimension: TextureDimension::D2,
Expand Down Expand Up @@ -451,8 +467,8 @@ pub fn prepare_lights(
),
},
ExtractedView {
width: POINT_SHADOW_SIZE.width,
height: POINT_SHADOW_SIZE.height,
width: point_light_shadow_map.size as u32,
height: point_light_shadow_map.size as u32,
transform: view_translation * view_rotation,
projection,
},
Expand Down Expand Up @@ -537,8 +553,8 @@ pub fn prepare_lights(
pass_name: format!("shadow pass directional light {}", i),
},
ExtractedView {
width: DIRECTIONAL_SHADOW_SIZE.width,
height: DIRECTIONAL_SHADOW_SIZE.height,
width: directional_light_shadow_map.size as u32,
height: directional_light_shadow_map.size as u32,
transform: GlobalTransform::from_matrix(view.inverse()),
projection,
},
Expand Down

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