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bevy/crates/bevy_pbr/src/light.rs
Yoh Deadfall 8b9aa2cceb Freeing memory held by visible entities vector (#3009) 
- Freeing unused memory held by visible entities
- Fixed comment style

# Objective

With Rust 1.56 it's possible to shrink vectors to a specified capacity. Visibility system had a comment before asking for that feature to free unused memory by a vector if its capacity is two times larger than the length.

## Solution

Shrinking the vector of visible entities to the nearest power of 2 elements next to `len()`, if capacity exceeds it more than two times.
2022-10-31 15:36:08 +00:00

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use std::collections::HashSet;
use bevy_ecs::prelude::*;
use bevy_math::{Mat4, UVec2, UVec3, Vec2, Vec3, Vec3A, Vec3Swizzles, Vec4, Vec4Swizzles};
use bevy_reflect::prelude::*;
use bevy_render::{
camera::{Camera, CameraProjection, OrthographicProjection},
color::Color,
extract_resource::ExtractResource,
primitives::{Aabb, CubemapFrusta, Frustum, Plane, Sphere},
render_resource::BufferBindingType,
renderer::RenderDevice,
view::{ComputedVisibility, RenderLayers, VisibleEntities},
};
use bevy_transform::{components::GlobalTransform, prelude::Transform};
use bevy_utils::tracing::warn;
use crate::{
calculate_cluster_factors, spot_light_projection_matrix, spot_light_view_matrix, CubeMapFace,
CubemapVisibleEntities, ViewClusterBindings, CLUSTERED_FORWARD_STORAGE_BUFFER_COUNT,
CUBE_MAP_FACES, MAX_UNIFORM_BUFFER_POINT_LIGHTS, POINT_LIGHT_NEAR_Z,
};
/// A light that emits light in all directions from a central point.
///
/// Real-world values for `intensity` (luminous power in lumens) based on the electrical power
/// consumption of the type of real-world light are:
///
/// | Luminous Power (lumen) (i.e. the intensity member) | Incandescent non-halogen (Watts) | Incandescent halogen (Watts) | Compact fluorescent (Watts) | LED (Watts |
/// |------|-----|----|--------|-------|
/// | 200 | 25 | | 3-5 | 3 |
/// | 450 | 40 | 29 | 9-11 | 5-8 |
/// | 800 | 60 | | 13-15 | 8-12 |
/// | 1100 | 75 | 53 | 18-20 | 10-16 |
/// | 1600 | 100 | 72 | 24-28 | 14-17 |
/// | 2400 | 150 | | 30-52 | 24-30 |
/// | 3100 | 200 | | 49-75 | 32 |
/// | 4000 | 300 | | 75-100 | 40.5 |
///
/// Source: [Wikipedia](https://en.wikipedia.org/wiki/Lumen_(unit)#Lighting)
#[derive(Component, Debug, Clone, Copy, Reflect)]
#[reflect(Component, Default)]
pub struct PointLight {
pub color: Color,
pub intensity: f32,
pub range: f32,
pub radius: f32,
pub shadows_enabled: bool,
pub shadow_depth_bias: f32,
/// A bias applied along the direction of the fragment's surface normal. It is scaled to the
/// shadow map's texel size so that it can be small close to the camera and gets larger further
/// away.
pub shadow_normal_bias: f32,
}
impl Default for PointLight {
fn default() -> Self {
PointLight {
color: Color::rgb(1.0, 1.0, 1.0),
/// Luminous power in lumens
intensity: 800.0, // Roughly a 60W non-halogen incandescent bulb
range: 20.0,
radius: 0.0,
shadows_enabled: false,
shadow_depth_bias: Self::DEFAULT_SHADOW_DEPTH_BIAS,
shadow_normal_bias: Self::DEFAULT_SHADOW_NORMAL_BIAS,
}
}
}
impl PointLight {
pub const DEFAULT_SHADOW_DEPTH_BIAS: f32 = 0.02;
pub const DEFAULT_SHADOW_NORMAL_BIAS: f32 = 0.6;
}
#[derive(Resource, Clone, Debug, Reflect)]
#[reflect(Resource)]
pub struct PointLightShadowMap {
pub size: usize,
}
impl Default for PointLightShadowMap {
fn default() -> Self {
Self { size: 1024 }
}
}
/// A light that emits light in a given direction from a central point.
/// Behaves like a point light in a perfectly absorbant housing that
/// shines light only in a given direction. The direction is taken from
/// the transform, and can be specified with [`Transform::looking_at`](bevy_transform::components::Transform::looking_at).
#[derive(Component, Debug, Clone, Copy, Reflect)]
#[reflect(Component, Default)]
pub struct SpotLight {
pub color: Color,
pub intensity: f32,
pub range: f32,
pub radius: f32,
pub shadows_enabled: bool,
pub shadow_depth_bias: f32,
/// A bias applied along the direction of the fragment's surface normal. It is scaled to the
/// shadow map's texel size so that it can be small close to the camera and gets larger further
/// away.
pub shadow_normal_bias: f32,
/// Angle defining the distance from the spot light direction to the outer limit
/// of the light's cone of effect.
/// `outer_angle` should be < `PI / 2.0`.
/// `PI / 2.0` defines a hemispherical spot light, but shadows become very blocky as the angle
/// approaches this limit.
pub outer_angle: f32,
/// Angle defining the distance from the spot light direction to the inner limit
/// of the light's cone of effect.
/// Light is attenuated from `inner_angle` to `outer_angle` to give a smooth falloff.
/// `inner_angle` should be <= `outer_angle`
pub inner_angle: f32,
}
impl SpotLight {
pub const DEFAULT_SHADOW_DEPTH_BIAS: f32 = 0.02;
pub const DEFAULT_SHADOW_NORMAL_BIAS: f32 = 0.6;
}
impl Default for SpotLight {
fn default() -> Self {
// a quarter arc attenuating from the centre
Self {
color: Color::rgb(1.0, 1.0, 1.0),
/// Luminous power in lumens
intensity: 800.0, // Roughly a 60W non-halogen incandescent bulb
range: 20.0,
radius: 0.0,
shadows_enabled: false,
shadow_depth_bias: Self::DEFAULT_SHADOW_DEPTH_BIAS,
shadow_normal_bias: Self::DEFAULT_SHADOW_NORMAL_BIAS,
inner_angle: 0.0,
outer_angle: std::f32::consts::FRAC_PI_4,
}
}
}
/// 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.
///
/// The light shines along the forward direction of the entity's transform. With a default transform
/// this would be along the negative-Z axis.
///
/// 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(Component, Debug, Clone, Reflect)]
#[reflect(Component, Default)]
pub struct DirectionalLight {
pub color: Color,
/// Illuminance in lux
pub illuminance: f32,
pub shadows_enabled: bool,
pub shadow_projection: OrthographicProjection,
pub shadow_depth_bias: f32,
/// A bias applied along the direction of the fragment's surface normal. It is scaled to the
/// shadow map's texel size so that it is automatically adjusted to the orthographic projection.
pub shadow_normal_bias: 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,
shadows_enabled: false,
shadow_projection: OrthographicProjection {
left: -size,
right: size,
bottom: -size,
top: size,
near: -size,
far: size,
..Default::default()
},
shadow_depth_bias: Self::DEFAULT_SHADOW_DEPTH_BIAS,
shadow_normal_bias: Self::DEFAULT_SHADOW_NORMAL_BIAS,
}
}
}
impl DirectionalLight {
pub const DEFAULT_SHADOW_DEPTH_BIAS: f32 = 0.02;
pub const DEFAULT_SHADOW_NORMAL_BIAS: f32 = 0.6;
}
#[derive(Resource, Clone, Debug, Reflect)]
#[reflect(Resource)]
pub struct DirectionalLightShadowMap {
pub size: usize,
}
impl Default for DirectionalLightShadowMap {
fn default() -> Self {
#[cfg(feature = "webgl")]
return Self { size: 2048 };
#[cfg(not(feature = "webgl"))]
return Self { size: 4096 };
}
}
/// An ambient light, which lights the entire scene equally.
#[derive(Resource, Clone, Debug, ExtractResource, Reflect)]
#[reflect(Resource)]
pub struct AmbientLight {
pub color: Color,
/// A direct scale factor multiplied with `color` before being passed to the shader.
pub brightness: f32,
}
impl Default for AmbientLight {
fn default() -> Self {
Self {
color: Color::rgb(1.0, 1.0, 1.0),
brightness: 0.05,
}
}
}
/// Add this component to make a [`Mesh`](bevy_render::mesh::Mesh) not cast shadows.
#[derive(Component, Reflect, Default)]
#[reflect(Component, Default)]
pub struct NotShadowCaster;
/// Add this component to make a [`Mesh`](bevy_render::mesh::Mesh) not receive shadows.
#[derive(Component, Reflect, Default)]
#[reflect(Component, Default)]
pub struct NotShadowReceiver;
#[derive(Debug, Hash, PartialEq, Eq, Clone, SystemLabel)]
pub enum SimulationLightSystems {
AddClusters,
AssignLightsToClusters,
UpdateLightFrusta,
CheckLightVisibility,
}
// Clustered-forward rendering notes
// The main initial reference material used was this rather accessible article:
// http://www.aortiz.me/2018/12/21/CG.html
// Some inspiration was taken from “Practical Clustered Shading” which is part 2 of:
// https://efficientshading.com/2015/01/01/real-time-many-light-management-and-shadows-with-clustered-shading/
// (Also note that Part 3 of the above shows how we could support the shadow mapping for many lights.)
// The z-slicing method mentioned in the aortiz article is originally from Tiago Sousa’s Siggraph 2016 talk about Doom 2016:
// http://advances.realtimerendering.com/s2016/Siggraph2016_idTech6.pdf
/// Configure the far z-plane mode used for the furthest depth slice for clustered forward
/// rendering
#[derive(Debug, Copy, Clone)]
pub enum ClusterFarZMode {
/// Calculate the required maximum z-depth based on currently visible lights.
/// Makes better use of available clusters, speeding up GPU lighting operations
/// at the expense of some CPU time and using more indices in the cluster light
/// index lists.
MaxLightRange,
/// Constant max z-depth
Constant(f32),
}
/// Configure the depth-slicing strategy for clustered forward rendering
#[derive(Debug, Copy, Clone)]
pub struct ClusterZConfig {
/// Far `Z` plane of the first depth slice
pub first_slice_depth: f32,
/// Strategy for how to evaluate the far `Z` plane of the furthest depth slice
pub far_z_mode: ClusterFarZMode,
}
impl Default for ClusterZConfig {
fn default() -> Self {
Self {
first_slice_depth: 5.0,
far_z_mode: ClusterFarZMode::MaxLightRange,
}
}
}
/// Configuration of the clustering strategy for clustered forward rendering
#[derive(Debug, Copy, Clone, Component)]
pub enum ClusterConfig {
/// Disable light cluster calculations for this view
None,
/// One single cluster. Optimal for low-light complexity scenes or scenes where
/// most lights affect the entire scene.
Single,
/// Explicit `X`, `Y` and `Z` counts (may yield non-square `X/Y` clusters depending on the aspect ratio)
XYZ {
dimensions: UVec3,
z_config: ClusterZConfig,
/// Specify if clusters should automatically resize in `X/Y` if there is a risk of exceeding
/// the available cluster-light index limit
dynamic_resizing: bool,
},
/// Fixed number of `Z` slices, `X` and `Y` calculated to give square clusters
/// with at most total clusters. For top-down games where lights will generally always be within a
/// short depth range, it may be useful to use this configuration with 1 or few `Z` slices. This
/// would reduce the number of lights per cluster by distributing more clusters in screen space
/// `X/Y` which matches how lights are distributed in the scene.
FixedZ {
total: u32,
z_slices: u32,
z_config: ClusterZConfig,
/// Specify if clusters should automatically resize in `X/Y` if there is a risk of exceeding
/// the available cluster-light index limit
dynamic_resizing: bool,
},
}
impl Default for ClusterConfig {
fn default() -> Self {
// 24 depth slices, square clusters with at most 4096 total clusters
// use max light distance as clusters max `Z`-depth, first slice extends to 5.0
Self::FixedZ {
total: 4096,
z_slices: 24,
z_config: ClusterZConfig::default(),
dynamic_resizing: true,
}
}
}
impl ClusterConfig {
fn dimensions_for_screen_size(&self, screen_size: UVec2) -> UVec3 {
match &self {
ClusterConfig::None => UVec3::ZERO,
ClusterConfig::Single => UVec3::ONE,
ClusterConfig::XYZ { dimensions, .. } => *dimensions,
ClusterConfig::FixedZ {
total, z_slices, ..
} => {
let aspect_ratio = screen_size.x as f32 / screen_size.y as f32;
let mut z_slices = *z_slices;
if *total < z_slices {
warn!("ClusterConfig has more z-slices than total clusters!");
z_slices = *total;
}
let per_layer = *total as f32 / z_slices as f32;
let y = f32::sqrt(per_layer / aspect_ratio);
let mut x = (y * aspect_ratio) as u32;
let mut y = y as u32;
// check extremes
if x == 0 {
x = 1;
y = per_layer as u32;
}
if y == 0 {
x = per_layer as u32;
y = 1;
}
UVec3::new(x, y, z_slices)
}
}
}
fn first_slice_depth(&self) -> f32 {
match self {
ClusterConfig::None | ClusterConfig::Single => 0.0,
ClusterConfig::XYZ { z_config, .. } | ClusterConfig::FixedZ { z_config, .. } => {
z_config.first_slice_depth
}
}
}
fn far_z_mode(&self) -> ClusterFarZMode {
match self {
ClusterConfig::None => ClusterFarZMode::Constant(0.0),
ClusterConfig::Single => ClusterFarZMode::MaxLightRange,
ClusterConfig::XYZ { z_config, .. } | ClusterConfig::FixedZ { z_config, .. } => {
z_config.far_z_mode
}
}
}
fn dynamic_resizing(&self) -> bool {
match self {
ClusterConfig::None | ClusterConfig::Single => false,
ClusterConfig::XYZ {
dynamic_resizing, ..
}
| ClusterConfig::FixedZ {
dynamic_resizing, ..
} => *dynamic_resizing,
}
}
}
#[derive(Component, Debug, Default)]
pub struct Clusters {
/// Tile size
pub(crate) tile_size: UVec2,
/// Number of clusters in `X` / `Y` / `Z` in the view frustum
pub(crate) dimensions: UVec3,
/// Distance to the far plane of the first depth slice. The first depth slice is special
/// and explicitly-configured to avoid having unnecessarily many slices close to the camera.
pub(crate) near: f32,
pub(crate) far: f32,
pub(crate) lights: Vec<VisiblePointLights>,
}
impl Clusters {
fn update(&mut self, screen_size: UVec2, requested_dimensions: UVec3) {
debug_assert!(
requested_dimensions.x > 0 && requested_dimensions.y > 0 && requested_dimensions.z > 0
);
let tile_size = (screen_size.as_vec2() / requested_dimensions.xy().as_vec2())
.ceil()
.as_uvec2()
.max(UVec2::ONE);
self.tile_size = tile_size;
self.dimensions = (screen_size.as_vec2() / tile_size.as_vec2())
.ceil()
.as_uvec2()
.extend(requested_dimensions.z)
.max(UVec3::ONE);
// NOTE: Maximum 4096 clusters due to uniform buffer size constraints
debug_assert!(self.dimensions.x * self.dimensions.y * self.dimensions.z <= 4096);
}
fn clear(&mut self) {
self.tile_size = UVec2::ONE;
self.dimensions = UVec3::ZERO;
self.near = 0.0;
self.far = 0.0;
self.lights.clear();
}
}
fn clip_to_view(inverse_projection: Mat4, clip: Vec4) -> Vec4 {
let view = inverse_projection * clip;
view / view.w
}
pub fn add_clusters(
mut commands: Commands,
cameras: Query<(Entity, Option<&ClusterConfig>), (With<Camera>, Without<Clusters>)>,
) {
for (entity, config) in &cameras {
let config = config.copied().unwrap_or_default();
// actual settings here don't matter - they will be overwritten in assign_lights_to_clusters
commands
.entity(entity)
.insert((Clusters::default(), config));
}
}
#[derive(Clone, Component, Debug, Default)]
pub struct VisiblePointLights {
pub(crate) entities: Vec<Entity>,
pub point_light_count: usize,
pub spot_light_count: usize,
}
impl VisiblePointLights {
#[inline]
pub fn iter(&self) -> impl DoubleEndedIterator<Item = &Entity> {
self.entities.iter()
}
#[inline]
pub fn len(&self) -> usize {
self.entities.len()
}
#[inline]
pub fn is_empty(&self) -> bool {
self.entities.is_empty()
}
}
// NOTE: Keep in sync with bevy_pbr/src/render/pbr.wgsl
fn view_z_to_z_slice(
cluster_factors: Vec2,
z_slices: u32,
view_z: f32,
is_orthographic: bool,
) -> u32 {
let z_slice = if is_orthographic {
// NOTE: view_z is correct in the orthographic case
((view_z - cluster_factors.x) * cluster_factors.y).floor() as u32
} else {
// NOTE: had to use -view_z to make it positive else log(negative) is nan
((-view_z).ln() * cluster_factors.x - cluster_factors.y + 1.0) as u32
};
// NOTE: We use min as we may limit the far z plane used for clustering to be closeer than
// the furthest thing being drawn. This means that we need to limit to the maximum cluster.
z_slice.min(z_slices - 1)
}
// NOTE: Keep in sync as the inverse of view_z_to_z_slice above
fn z_slice_to_view_z(
near: f32,
far: f32,
z_slices: u32,
z_slice: u32,
is_orthographic: bool,
) -> f32 {
if is_orthographic {
return -near - (far - near) * z_slice as f32 / z_slices as f32;
}
// Perspective
if z_slice == 0 {
0.0
} else {
-near * (far / near).powf((z_slice - 1) as f32 / (z_slices - 1) as f32)
}
}
fn ndc_position_to_cluster(
cluster_dimensions: UVec3,
cluster_factors: Vec2,
is_orthographic: bool,
ndc_p: Vec3,
view_z: f32,
) -> UVec3 {
let cluster_dimensions_f32 = cluster_dimensions.as_vec3();
let frag_coord = (ndc_p.xy() * VEC2_HALF_NEGATIVE_Y + VEC2_HALF).clamp(Vec2::ZERO, Vec2::ONE);
let xy = (frag_coord * cluster_dimensions_f32.xy()).floor();
let z_slice = view_z_to_z_slice(
cluster_factors,
cluster_dimensions.z,
view_z,
is_orthographic,
);
xy.as_uvec2()
.extend(z_slice)
.clamp(UVec3::ZERO, cluster_dimensions - UVec3::ONE)
}
const VEC2_HALF: Vec2 = Vec2::splat(0.5);
const VEC2_HALF_NEGATIVE_Y: Vec2 = Vec2::new(0.5, -0.5);
/// Calculate bounds for the light using a view space aabb.
/// Returns a `(Vec3, Vec3)` containing minimum and maximum with
/// `X` and `Y` in normalized device coordinates with range `[-1, 1]`
/// `Z` in view space, with range `[-inf, -f32::MIN_POSITIVE]`
fn cluster_space_light_aabb(
inverse_view_transform: Mat4,
projection_matrix: Mat4,
light_sphere: &Sphere,
) -> (Vec3, Vec3) {
let light_aabb_view = Aabb {
center: Vec3A::from(inverse_view_transform * light_sphere.center.extend(1.0)),
half_extents: Vec3A::splat(light_sphere.radius),
};
let (mut light_aabb_view_min, mut light_aabb_view_max) =
(light_aabb_view.min(), light_aabb_view.max());
// Constrain view z to be negative - i.e. in front of the camera
// When view z is >= 0.0 and we're using a perspective projection, bad things happen.
// At view z == 0.0, ndc x,y are mathematically undefined. At view z > 0.0, i.e. behind the camera,
// the perspective projection flips the directions of the axes. This breaks assumptions about
// use of min/max operations as something that was to the left in view space is now returning a
// coordinate that for view z in front of the camera would be on the right, but at view z behind the
// camera is on the left. So, we just constrain view z to be < 0.0 and necessarily in front of the camera.
light_aabb_view_min.z = light_aabb_view_min.z.min(-f32::MIN_POSITIVE);
light_aabb_view_max.z = light_aabb_view_max.z.min(-f32::MIN_POSITIVE);
// Is there a cheaper way to do this? The problem is that because of perspective
// the point at max z but min xy may be less xy in screenspace, and similar. As
// such, projecting the min and max xy at both the closer and further z and taking
// the min and max of those projected points addresses this.
let (
light_aabb_view_xymin_near,
light_aabb_view_xymin_far,
light_aabb_view_xymax_near,
light_aabb_view_xymax_far,
) = (
light_aabb_view_min,
light_aabb_view_min.xy().extend(light_aabb_view_max.z),
light_aabb_view_max.xy().extend(light_aabb_view_min.z),
light_aabb_view_max,
);
let (
light_aabb_clip_xymin_near,
light_aabb_clip_xymin_far,
light_aabb_clip_xymax_near,
light_aabb_clip_xymax_far,
) = (
projection_matrix * light_aabb_view_xymin_near.extend(1.0),
projection_matrix * light_aabb_view_xymin_far.extend(1.0),
projection_matrix * light_aabb_view_xymax_near.extend(1.0),
projection_matrix * light_aabb_view_xymax_far.extend(1.0),
);
let (
light_aabb_ndc_xymin_near,
light_aabb_ndc_xymin_far,
light_aabb_ndc_xymax_near,
light_aabb_ndc_xymax_far,
) = (
light_aabb_clip_xymin_near.xyz() / light_aabb_clip_xymin_near.w,
light_aabb_clip_xymin_far.xyz() / light_aabb_clip_xymin_far.w,
light_aabb_clip_xymax_near.xyz() / light_aabb_clip_xymax_near.w,
light_aabb_clip_xymax_far.xyz() / light_aabb_clip_xymax_far.w,
);
let (light_aabb_ndc_min, light_aabb_ndc_max) = (
light_aabb_ndc_xymin_near
.min(light_aabb_ndc_xymin_far)
.min(light_aabb_ndc_xymax_near)
.min(light_aabb_ndc_xymax_far),
light_aabb_ndc_xymin_near
.max(light_aabb_ndc_xymin_far)
.max(light_aabb_ndc_xymax_near)
.max(light_aabb_ndc_xymax_far),
);
// clamp to ndc coords without depth
let (aabb_min_ndc, aabb_max_ndc) = (
light_aabb_ndc_min.xy().clamp(NDC_MIN, NDC_MAX),
light_aabb_ndc_max.xy().clamp(NDC_MIN, NDC_MAX),
);
// pack unadjusted z depth into the vecs
(
aabb_min_ndc.extend(light_aabb_view_min.z),
aabb_max_ndc.extend(light_aabb_view_max.z),
)
}
fn screen_to_view(screen_size: Vec2, inverse_projection: Mat4, screen: Vec2, ndc_z: f32) -> Vec4 {
let tex_coord = screen / screen_size;
let clip = Vec4::new(
tex_coord.x * 2.0 - 1.0,
(1.0 - tex_coord.y) * 2.0 - 1.0,
ndc_z,
1.0,
);
clip_to_view(inverse_projection, clip)
}
const NDC_MIN: Vec2 = Vec2::NEG_ONE;
const NDC_MAX: Vec2 = Vec2::ONE;
// Calculate the intersection of a ray from the eye through the view space position to a z plane
fn line_intersection_to_z_plane(origin: Vec3, p: Vec3, z: f32) -> Vec3 {
let v = p - origin;
let t = (z - Vec3::Z.dot(origin)) / Vec3::Z.dot(v);
origin + t * v
}
#[allow(clippy::too_many_arguments)]
fn compute_aabb_for_cluster(
z_near: f32,
z_far: f32,
tile_size: Vec2,
screen_size: Vec2,
inverse_projection: Mat4,
is_orthographic: bool,
cluster_dimensions: UVec3,
ijk: UVec3,
) -> Aabb {
let ijk = ijk.as_vec3();
// Calculate the minimum and maximum points in screen space
let p_min = ijk.xy() * tile_size;
let p_max = p_min + tile_size;
let cluster_min;
let cluster_max;
if is_orthographic {
// Use linear depth slicing for orthographic
// Convert to view space at the cluster near and far planes
// NOTE: 1.0 is the near plane due to using reverse z projections
let p_min = screen_to_view(
screen_size,
inverse_projection,
p_min,
1.0 - (ijk.z / cluster_dimensions.z as f32),
)
.xyz();
let p_max = screen_to_view(
screen_size,
inverse_projection,
p_max,
1.0 - ((ijk.z + 1.0) / cluster_dimensions.z as f32),
)
.xyz();
cluster_min = p_min.min(p_max);
cluster_max = p_min.max(p_max);
} else {
// Convert to view space at the near plane
// NOTE: 1.0 is the near plane due to using reverse z projections
let p_min = screen_to_view(screen_size, inverse_projection, p_min, 1.0);
let p_max = screen_to_view(screen_size, inverse_projection, p_max, 1.0);
let z_far_over_z_near = -z_far / -z_near;
let cluster_near = if ijk.z == 0.0 {
0.0
} else {
-z_near * z_far_over_z_near.powf((ijk.z - 1.0) / (cluster_dimensions.z - 1) as f32)
};
// NOTE: This could be simplified to:
// cluster_far = cluster_near * z_far_over_z_near;
let cluster_far = if cluster_dimensions.z == 1 {
-z_far
} else {
-z_near * z_far_over_z_near.powf(ijk.z / (cluster_dimensions.z - 1) as f32)
};
// Calculate the four intersection points of the min and max points with the cluster near and far planes
let p_min_near = line_intersection_to_z_plane(Vec3::ZERO, p_min.xyz(), cluster_near);
let p_min_far = line_intersection_to_z_plane(Vec3::ZERO, p_min.xyz(), cluster_far);
let p_max_near = line_intersection_to_z_plane(Vec3::ZERO, p_max.xyz(), cluster_near);
let p_max_far = line_intersection_to_z_plane(Vec3::ZERO, p_max.xyz(), cluster_far);
cluster_min = p_min_near.min(p_min_far).min(p_max_near.min(p_max_far));
cluster_max = p_min_near.max(p_min_far).max(p_max_near.max(p_max_far));
}
Aabb::from_min_max(cluster_min, cluster_max)
}
// Sort lights by
// - point-light vs spot-light, so that we can iterate point lights and spot lights in contiguous blocks in the fragment shader,
// - then those with shadows enabled first, so that the index can be used to render at most `point_light_shadow_maps_count`
// point light shadows and `spot_light_shadow_maps_count` spot light shadow maps,
// - then by entity as a stable key to ensure that a consistent set of lights are chosen if the light count limit is exceeded.
pub(crate) fn point_light_order(
(entity_1, shadows_enabled_1, is_spot_light_1): (&Entity, &bool, &bool),
(entity_2, shadows_enabled_2, is_spot_light_2): (&Entity, &bool, &bool),
) -> std::cmp::Ordering {
is_spot_light_1
.cmp(is_spot_light_2) // pointlights before spot lights
.then_with(|| shadows_enabled_2.cmp(shadows_enabled_1)) // shadow casters before non-casters
.then_with(|| entity_1.cmp(entity_2)) // stable
}
#[derive(Clone, Copy)]
// data required for assigning lights to clusters
pub(crate) struct PointLightAssignmentData {
entity: Entity,
transform: GlobalTransform,
range: f32,
shadows_enabled: bool,
spot_light_angle: Option<f32>,
}
impl PointLightAssignmentData {
pub fn sphere(&self) -> Sphere {
Sphere {
center: self.transform.translation_vec3a(),
radius: self.range,
}
}
}
#[derive(Resource, Default)]
pub struct GlobalVisiblePointLights {
entities: HashSet<Entity>,
}
impl GlobalVisiblePointLights {
#[inline]
pub fn iter(&self) -> impl Iterator<Item = &Entity> {
self.entities.iter()
}
#[inline]
pub fn contains(&self, entity: Entity) -> bool {
self.entities.contains(&entity)
}
}
// NOTE: Run this before update_point_light_frusta!
#[allow(clippy::too_many_arguments)]
pub(crate) fn assign_lights_to_clusters(
mut commands: Commands,
mut global_lights: ResMut<GlobalVisiblePointLights>,
mut views: Query<(
Entity,
&GlobalTransform,
&Camera,
&Frustum,
&ClusterConfig,
&mut Clusters,
Option<&mut VisiblePointLights>,
)>,
point_lights_query: Query<(Entity, &GlobalTransform, &PointLight, &ComputedVisibility)>,
spot_lights_query: Query<(Entity, &GlobalTransform, &SpotLight, &ComputedVisibility)>,
mut lights: Local<Vec<PointLightAssignmentData>>,
mut cluster_aabb_spheres: Local<Vec<Option<Sphere>>>,
mut max_point_lights_warning_emitted: Local<bool>,
render_device: Option<Res<RenderDevice>>,
) {
let render_device = match render_device {
Some(render_device) => render_device,
None => return,
};
global_lights.entities.clear();
lights.clear();
// collect just the relevant light query data into a persisted vec to avoid reallocating each frame
lights.extend(
point_lights_query
.iter()
.filter(|(.., visibility)| visibility.is_visible())
.map(
|(entity, transform, point_light, _visibility)| PointLightAssignmentData {
entity,
transform: GlobalTransform::from_translation(transform.translation()),
shadows_enabled: point_light.shadows_enabled,
range: point_light.range,
spot_light_angle: None,
},
),
);
lights.extend(
spot_lights_query
.iter()
.filter(|(.., visibility)| visibility.is_visible())
.map(
|(entity, transform, spot_light, _visibility)| PointLightAssignmentData {
entity,
transform: *transform,
shadows_enabled: spot_light.shadows_enabled,
range: spot_light.range,
spot_light_angle: Some(spot_light.outer_angle),
},
),
);
let clustered_forward_buffer_binding_type =
render_device.get_supported_read_only_binding_type(CLUSTERED_FORWARD_STORAGE_BUFFER_COUNT);
let supports_storage_buffers = matches!(
clustered_forward_buffer_binding_type,
BufferBindingType::Storage { .. }
);
if lights.len() > MAX_UNIFORM_BUFFER_POINT_LIGHTS && !supports_storage_buffers {
lights.sort_by(|light_1, light_2| {
point_light_order(
(
&light_1.entity,
&light_1.shadows_enabled,
&light_1.spot_light_angle.is_some(),
),
(
&light_2.entity,
&light_2.shadows_enabled,
&light_2.spot_light_angle.is_some(),
),
)
});
// check each light against each view's frustum, keep only those that affect at least one of our views
let frusta: Vec<_> = views
.iter()
.map(|(_, _, _, frustum, _, _, _)| *frustum)
.collect();
let mut lights_in_view_count = 0;
lights.retain(|light| {
// take one extra light to check if we should emit the warning
if lights_in_view_count == MAX_UNIFORM_BUFFER_POINT_LIGHTS + 1 {
false
} else {
let light_sphere = light.sphere();
let light_in_view = frusta
.iter()
.any(|frustum| frustum.intersects_sphere(&light_sphere, true));
if light_in_view {
lights_in_view_count += 1;
}
light_in_view
}
});
if lights.len() > MAX_UNIFORM_BUFFER_POINT_LIGHTS && !*max_point_lights_warning_emitted {
warn!(
"MAX_UNIFORM_BUFFER_POINT_LIGHTS ({}) exceeded",
MAX_UNIFORM_BUFFER_POINT_LIGHTS
);
*max_point_lights_warning_emitted = true;
}
lights.truncate(MAX_UNIFORM_BUFFER_POINT_LIGHTS);
}
for (view_entity, camera_transform, camera, frustum, config, clusters, mut visible_lights) in
&mut views
{
let clusters = clusters.into_inner();
if matches!(config, ClusterConfig::None) {
if visible_lights.is_some() {
commands.entity(view_entity).remove::<VisiblePointLights>();
}
clusters.clear();
continue;
}
let screen_size = if let Some(screen_size) = camera.physical_viewport_size() {
screen_size
} else {
clusters.clear();
continue;
};
let mut requested_cluster_dimensions = config.dimensions_for_screen_size(screen_size);
let view_transform = camera_transform.compute_matrix();
let inverse_view_transform = view_transform.inverse();
let is_orthographic = camera.projection_matrix().w_axis.w == 1.0;
let far_z = match config.far_z_mode() {
ClusterFarZMode::MaxLightRange => {
let inverse_view_row_2 = inverse_view_transform.row(2);
lights
.iter()
.map(|light| {
-inverse_view_row_2.dot(light.transform.translation().extend(1.0))
+ light.range
})
.reduce(f32::max)
.unwrap_or(0.0)
}
ClusterFarZMode::Constant(far) => far,
};
let first_slice_depth = match (is_orthographic, requested_cluster_dimensions.z) {
(true, _) => {
// NOTE: Based on glam's Mat4::orthographic_rh(), as used to calculate the orthographic projection
// matrix, we can calculate the projection's view-space near plane as follows:
// component 3,2 = r * near and 2,2 = r where r = 1.0 / (near - far)
// There is a caveat here that when calculating the projection matrix, near and far were swapped to give
// reversed z, consistent with the perspective projection. So,
// 3,2 = r * far and 2,2 = r where r = 1.0 / (far - near)
// rearranging r = 1.0 / (far - near), r * (far - near) = 1.0, r * far - 1.0 = r * near, near = (r * far - 1.0) / r
// = (3,2 - 1.0) / 2,2
(camera.projection_matrix().w_axis.z - 1.0) / camera.projection_matrix().z_axis.z
}
(false, 1) => config.first_slice_depth().max(far_z),
_ => config.first_slice_depth(),
};
// NOTE: Ensure the far_z is at least as far as the first_depth_slice to avoid clustering problems.
let far_z = far_z.max(first_slice_depth);
let cluster_factors = calculate_cluster_factors(
first_slice_depth,
far_z,
requested_cluster_dimensions.z as f32,
is_orthographic,
);
if config.dynamic_resizing() {
let mut cluster_index_estimate = 0.0;
for light in &lights {
let light_sphere = light.sphere();
// Check if the light is within the view frustum
if !frustum.intersects_sphere(&light_sphere, true) {
continue;
}
// calculate a conservative aabb estimate of number of clusters affected by this light
// this overestimates index counts by at most 50% (and typically much less) when the whole light range is in view
// it can overestimate more significantly when light ranges are only partially in view
let (light_aabb_min, light_aabb_max) = cluster_space_light_aabb(
inverse_view_transform,
camera.projection_matrix(),
&light_sphere,
);
// since we won't adjust z slices we can calculate exact number of slices required in z dimension
let z_cluster_min = view_z_to_z_slice(
cluster_factors,
requested_cluster_dimensions.z,
light_aabb_min.z,
is_orthographic,
);
let z_cluster_max = view_z_to_z_slice(
cluster_factors,
requested_cluster_dimensions.z,
light_aabb_max.z,
is_orthographic,
);
let z_count =
z_cluster_min.max(z_cluster_max) - z_cluster_min.min(z_cluster_max) + 1;
// calculate x/y count using floats to avoid overestimating counts due to large initial tile sizes
let xy_min = light_aabb_min.xy();
let xy_max = light_aabb_max.xy();
// multiply by 0.5 to move from [-1,1] to [-0.5, 0.5], max extent of 1 in each dimension
let xy_count = (xy_max - xy_min)
* 0.5
* Vec2::new(
requested_cluster_dimensions.x as f32,
requested_cluster_dimensions.y as f32,
);
// add up to 2 to each axis to account for overlap
let x_overlap = if xy_min.x <= -1.0 { 0.0 } else { 1.0 }
+ if xy_max.x >= 1.0 { 0.0 } else { 1.0 };
let y_overlap = if xy_min.y <= -1.0 { 0.0 } else { 1.0 }
+ if xy_max.y >= 1.0 { 0.0 } else { 1.0 };
cluster_index_estimate +=
(xy_count.x + x_overlap) * (xy_count.y + y_overlap) * z_count as f32;
}
if cluster_index_estimate > ViewClusterBindings::MAX_INDICES as f32 {
// scale x and y cluster count to be able to fit all our indices
// we take the ratio of the actual indices over the index estimate.
// this not not guaranteed to be small enough due to overlapped tiles, but
// the conservative estimate is more than sufficient to cover the
// difference
let index_ratio = ViewClusterBindings::MAX_INDICES as f32 / cluster_index_estimate;
let xy_ratio = index_ratio.sqrt();
requested_cluster_dimensions.x =
((requested_cluster_dimensions.x as f32 * xy_ratio).floor() as u32).max(1);
requested_cluster_dimensions.y =
((requested_cluster_dimensions.y as f32 * xy_ratio).floor() as u32).max(1);
}
}
clusters.update(screen_size, requested_cluster_dimensions);
clusters.near = first_slice_depth;
clusters.far = far_z;
// NOTE: Maximum 4096 clusters due to uniform buffer size constraints
debug_assert!(
clusters.dimensions.x * clusters.dimensions.y * clusters.dimensions.z <= 4096
);
let inverse_projection = camera.projection_matrix().inverse();
for lights in &mut clusters.lights {
lights.entities.clear();
lights.point_light_count = 0;
lights.spot_light_count = 0;
}
let cluster_count =
(clusters.dimensions.x * clusters.dimensions.y * clusters.dimensions.z) as usize;
clusters
.lights
.resize_with(cluster_count, VisiblePointLights::default);
// initialize empty cluster bounding spheres
cluster_aabb_spheres.clear();
cluster_aabb_spheres.extend(std::iter::repeat(None).take(cluster_count));
// Calculate the x/y/z cluster frustum planes in view space
let mut x_planes = Vec::with_capacity(clusters.dimensions.x as usize + 1);
let mut y_planes = Vec::with_capacity(clusters.dimensions.y as usize + 1);
let mut z_planes = Vec::with_capacity(clusters.dimensions.z as usize + 1);
if is_orthographic {
let x_slices = clusters.dimensions.x as f32;
for x in 0..=clusters.dimensions.x {
let x_proportion = x as f32 / x_slices;
let x_pos = x_proportion * 2.0 - 1.0;
let view_x = clip_to_view(inverse_projection, Vec4::new(x_pos, 0.0, 1.0, 1.0)).x;
let normal = Vec3::X;
let d = view_x * normal.x;
x_planes.push(Plane::new(normal.extend(d)));
}
let y_slices = clusters.dimensions.y as f32;
for y in 0..=clusters.dimensions.y {
let y_proportion = 1.0 - y as f32 / y_slices;
let y_pos = y_proportion * 2.0 - 1.0;
let view_y = clip_to_view(inverse_projection, Vec4::new(0.0, y_pos, 1.0, 1.0)).y;
let normal = Vec3::Y;
let d = view_y * normal.y;
y_planes.push(Plane::new(normal.extend(d)));
}
} else {
let x_slices = clusters.dimensions.x as f32;
for x in 0..=clusters.dimensions.x {
let x_proportion = x as f32 / x_slices;
let x_pos = x_proportion * 2.0 - 1.0;
let nb = clip_to_view(inverse_projection, Vec4::new(x_pos, -1.0, 1.0, 1.0)).xyz();
let nt = clip_to_view(inverse_projection, Vec4::new(x_pos, 1.0, 1.0, 1.0)).xyz();
let normal = nb.cross(nt);
let d = nb.dot(normal);
x_planes.push(Plane::new(normal.extend(d)));
}
let y_slices = clusters.dimensions.y as f32;
for y in 0..=clusters.dimensions.y {
let y_proportion = 1.0 - y as f32 / y_slices;
let y_pos = y_proportion * 2.0 - 1.0;
let nl = clip_to_view(inverse_projection, Vec4::new(-1.0, y_pos, 1.0, 1.0)).xyz();
let nr = clip_to_view(inverse_projection, Vec4::new(1.0, y_pos, 1.0, 1.0)).xyz();
let normal = nr.cross(nl);
let d = nr.dot(normal);
y_planes.push(Plane::new(normal.extend(d)));
}
}
let z_slices = clusters.dimensions.z;
for z in 0..=z_slices {
let view_z = z_slice_to_view_z(first_slice_depth, far_z, z_slices, z, is_orthographic);
let normal = -Vec3::Z;
let d = view_z * normal.z;
z_planes.push(Plane::new(normal.extend(d)));
}
let mut update_from_light_intersections = |visible_lights: &mut Vec<Entity>| {
for light in &lights {
let light_sphere = light.sphere();
// Check if the light is within the view frustum
if !frustum.intersects_sphere(&light_sphere, true) {
continue;
}
// NOTE: The light intersects the frustum so it must be visible and part of the global set
global_lights.entities.insert(light.entity);
visible_lights.push(light.entity);
// note: caching seems to be slower than calling twice for this aabb calculation
let (light_aabb_xy_ndc_z_view_min, light_aabb_xy_ndc_z_view_max) =
cluster_space_light_aabb(
inverse_view_transform,
camera.projection_matrix(),
&light_sphere,
);
let min_cluster = ndc_position_to_cluster(
clusters.dimensions,
cluster_factors,
is_orthographic,
light_aabb_xy_ndc_z_view_min,
light_aabb_xy_ndc_z_view_min.z,
);
let max_cluster = ndc_position_to_cluster(
clusters.dimensions,
cluster_factors,
is_orthographic,
light_aabb_xy_ndc_z_view_max,
light_aabb_xy_ndc_z_view_max.z,
);
let (min_cluster, max_cluster) =
(min_cluster.min(max_cluster), min_cluster.max(max_cluster));
// What follows is the Iterative Sphere Refinement algorithm from Just Cause 3
// Persson et al, Practical Clustered Shading
// http://newq.net/dl/pub/s2015_practical.pdf
// NOTE: A sphere under perspective projection is no longer a sphere. It gets
// stretched and warped, which prevents simpler algorithms from being correct
// as they often assume that the widest part of the sphere under projection is the
// center point on the axis of interest plus the radius, and that is not true!
let view_light_sphere = Sphere {
center: Vec3A::from(inverse_view_transform * light_sphere.center.extend(1.0)),
radius: light_sphere.radius,
};
let spot_light_dir_sin_cos = light.spot_light_angle.map(|angle| {
let (angle_sin, angle_cos) = angle.sin_cos();
(
(inverse_view_transform * light.transform.back().extend(0.0)).truncate(),
angle_sin,
angle_cos,
)
});
let light_center_clip =
camera.projection_matrix() * view_light_sphere.center.extend(1.0);
let light_center_ndc = light_center_clip.xyz() / light_center_clip.w;
let cluster_coordinates = ndc_position_to_cluster(
clusters.dimensions,
cluster_factors,
is_orthographic,
light_center_ndc,
view_light_sphere.center.z,
);
let z_center = if light_center_ndc.z <= 1.0 {
Some(cluster_coordinates.z)
} else {
None
};
let y_center = if light_center_ndc.y > 1.0 {
None
} else if light_center_ndc.y < -1.0 {
Some(clusters.dimensions.y + 1)
} else {
Some(cluster_coordinates.y)
};
for z in min_cluster.z..=max_cluster.z {
let mut z_light = view_light_sphere.clone();
if z_center.is_none() || z != z_center.unwrap() {
// The z plane closer to the light has the larger radius circle where the
// light sphere intersects the z plane.
let z_plane = if z_center.is_some() && z < z_center.unwrap() {
z_planes[(z + 1) as usize]
} else {
z_planes[z as usize]
};
// Project the sphere to this z plane and use its radius as the radius of a
// new, refined sphere.
if let Some(projected) = project_to_plane_z(z_light, z_plane) {
z_light = projected;
} else {
continue;
}
}
for y in min_cluster.y..=max_cluster.y {
let mut y_light = z_light.clone();
if y_center.is_none() || y != y_center.unwrap() {
// The y plane closer to the light has the larger radius circle where the
// light sphere intersects the y plane.
let y_plane = if y_center.is_some() && y < y_center.unwrap() {
y_planes[(y + 1) as usize]
} else {
y_planes[y as usize]
};
// Project the refined sphere to this y plane and use its radius as the
// radius of a new, even more refined sphere.
if let Some(projected) =
project_to_plane_y(y_light, y_plane, is_orthographic)
{
y_light = projected;
} else {
continue;
}
}
// Loop from the left to find the first affected cluster
let mut min_x = min_cluster.x;
loop {
if min_x >= max_cluster.x
|| -get_distance_x(
x_planes[(min_x + 1) as usize],
y_light.center,
is_orthographic,
) + y_light.radius
> 0.0
{
break;
}
min_x += 1;
}
// Loop from the right to find the last affected cluster
let mut max_x = max_cluster.x;
loop {
if max_x <= min_x
|| get_distance_x(
x_planes[max_x as usize],
y_light.center,
is_orthographic,
) + y_light.radius
> 0.0
{
break;
}
max_x -= 1;
}
let mut cluster_index = ((y * clusters.dimensions.x + min_x)
* clusters.dimensions.z
+ z) as usize;
if let Some((view_light_direction, angle_sin, angle_cos)) =
spot_light_dir_sin_cos
{
for x in min_x..=max_x {
// further culling for spot lights
// get or initialize cluster bounding sphere
let cluster_aabb_sphere = &mut cluster_aabb_spheres[cluster_index];
let cluster_aabb_sphere = if let Some(sphere) = cluster_aabb_sphere
{
&*sphere
} else {
let aabb = compute_aabb_for_cluster(
first_slice_depth,
far_z,
clusters.tile_size.as_vec2(),
screen_size.as_vec2(),
inverse_projection,
is_orthographic,
clusters.dimensions,
UVec3::new(x, y, z),
);
let sphere = Sphere {
center: aabb.center,
radius: aabb.half_extents.length(),
};
*cluster_aabb_sphere = Some(sphere);
cluster_aabb_sphere.as_ref().unwrap()
};
// test -- based on https://bartwronski.com/2017/04/13/cull-that-cone/
let spot_light_offset = Vec3::from(
view_light_sphere.center - cluster_aabb_sphere.center,
);
let spot_light_dist_sq = spot_light_offset.length_squared();
let v1_len = spot_light_offset.dot(view_light_direction);
let distance_closest_point = (angle_cos
* (spot_light_dist_sq - v1_len * v1_len).sqrt())
- v1_len * angle_sin;
let angle_cull =
distance_closest_point > cluster_aabb_sphere.radius;
let front_cull = v1_len > cluster_aabb_sphere.radius + light.range;
let back_cull = v1_len < -cluster_aabb_sphere.radius;
if !angle_cull && !front_cull && !back_cull {
// this cluster is affected by the spot light
clusters.lights[cluster_index].entities.push(light.entity);
clusters.lights[cluster_index].spot_light_count += 1;
}
cluster_index += clusters.dimensions.z as usize;
}
} else {
for _ in min_x..=max_x {
// all clusters within range are affected by point lights
clusters.lights[cluster_index].entities.push(light.entity);
clusters.lights[cluster_index].point_light_count += 1;
cluster_index += clusters.dimensions.z as usize;
}
}
}
}
}
};
// reuse existing visible lights Vec, if it exists
if let Some(visible_lights) = visible_lights.as_mut() {
visible_lights.entities.clear();
update_from_light_intersections(&mut visible_lights.entities);
} else {
let mut entities = Vec::new();
update_from_light_intersections(&mut entities);
commands.entity(view_entity).insert(VisiblePointLights {
entities,
..Default::default()
});
}
}
}
// NOTE: This exploits the fact that a x-plane normal has only x and z components
fn get_distance_x(plane: Plane, point: Vec3A, is_orthographic: bool) -> f32 {
if is_orthographic {
point.x - plane.d()
} else {
// Distance from a point to a plane:
// signed distance to plane = (nx * px + ny * py + nz * pz + d) / n.length()
// NOTE: For a x-plane, ny and d are 0 and we have a unit normal
// = nx * px + nz * pz
plane.normal_d().xz().dot(point.xz())
}
}
// NOTE: This exploits the fact that a z-plane normal has only a z component
fn project_to_plane_z(z_light: Sphere, z_plane: Plane) -> Option<Sphere> {
// p = sphere center
// n = plane normal
// d = n.p if p is in the plane
// NOTE: For a z-plane, nx and ny are both 0
// d = px * nx + py * ny + pz * nz
// = pz * nz
// => pz = d / nz
let z = z_plane.d() / z_plane.normal_d().z;
let distance_to_plane = z - z_light.center.z;
if distance_to_plane.abs() > z_light.radius {
return None;
}
Some(Sphere {
center: Vec3A::from(z_light.center.xy().extend(z)),
// hypotenuse length = radius
// pythagorus = (distance to plane)^2 + b^2 = radius^2
radius: (z_light.radius * z_light.radius - distance_to_plane * distance_to_plane).sqrt(),
})
}
// NOTE: This exploits the fact that a y-plane normal has only y and z components
fn project_to_plane_y(y_light: Sphere, y_plane: Plane, is_orthographic: bool) -> Option<Sphere> {
let distance_to_plane = if is_orthographic {
y_plane.d() - y_light.center.y
} else {
-y_light.center.yz().dot(y_plane.normal_d().yz())
};
if distance_to_plane.abs() > y_light.radius {
return None;
}
Some(Sphere {
center: y_light.center + distance_to_plane * y_plane.normal(),
radius: (y_light.radius * y_light.radius - distance_to_plane * distance_to_plane).sqrt(),
})
}
pub fn update_directional_light_frusta(
mut views: Query<
(
&GlobalTransform,
&DirectionalLight,
&mut Frustum,
&ComputedVisibility,
),
(
Or<(Changed<GlobalTransform>, Changed<DirectionalLight>)>,
// Prevents this query from conflicting with camera queries.
Without<Camera>,
),
>,
) {
for (transform, directional_light, mut frustum, visibility) in &mut views {
// The frustum is used for culling meshes to the light for shadow mapping
// so if shadow mapping is disabled for this light, then the frustum is
// not needed.
if !directional_light.shadows_enabled || !visibility.is_visible() {
continue;
}
let view_projection = directional_light.shadow_projection.get_projection_matrix()
* transform.compute_matrix().inverse();
*frustum = Frustum::from_view_projection(
&view_projection,
&transform.translation(),
&transform.back(),
directional_light.shadow_projection.far(),
);
}
}
// NOTE: Run this after assign_lights_to_clusters!
pub fn update_point_light_frusta(
global_lights: Res<GlobalVisiblePointLights>,
mut views: Query<
(Entity, &GlobalTransform, &PointLight, &mut CubemapFrusta),
Or<(Changed<GlobalTransform>, Changed<PointLight>)>,
>,
) {
let projection =
Mat4::perspective_infinite_reverse_rh(std::f32::consts::FRAC_PI_2, 1.0, POINT_LIGHT_NEAR_Z);
let view_rotations = CUBE_MAP_FACES
.iter()
.map(|CubeMapFace { target, up }| Transform::IDENTITY.looking_at(*target, *up))
.collect::<Vec<_>>();
for (entity, transform, point_light, mut cubemap_frusta) in &mut views {
// The frusta are used for culling meshes to the light for shadow mapping
// so if shadow mapping is disabled for this light, then the frusta are
// not needed.
// Also, if the light is not relevant for any cluster, it will not be in the
// global lights set and so there is no need to update its frusta.
if !point_light.shadows_enabled || !global_lights.entities.contains(&entity) {
continue;
}
// ignore scale because we don't want to effectively scale light radius and range
// by applying those as a view transform to shadow map rendering of objects
// and ignore rotation because we want the shadow map projections to align with the axes
let view_translation = Transform::from_translation(transform.translation());
let view_backward = transform.back();
for (view_rotation, frustum) in view_rotations.iter().zip(cubemap_frusta.iter_mut()) {
let view = view_translation * *view_rotation;
let view_projection = projection * view.compute_matrix().inverse();
*frustum = Frustum::from_view_projection(
&view_projection,
&transform.translation(),
&view_backward,
point_light.range,
);
}
}
}
pub fn update_spot_light_frusta(
global_lights: Res<GlobalVisiblePointLights>,
mut views: Query<
(Entity, &GlobalTransform, &SpotLight, &mut Frustum),
Or<(Changed<GlobalTransform>, Changed<SpotLight>)>,
>,
) {
for (entity, transform, spot_light, mut frustum) in views.iter_mut() {
// The frusta are used for culling meshes to the light for shadow mapping
// so if shadow mapping is disabled for this light, then the frusta are
// not needed.
// Also, if the light is not relevant for any cluster, it will not be in the
// global lights set and so there is no need to update its frusta.
if !spot_light.shadows_enabled || !global_lights.entities.contains(&entity) {
continue;
}
// ignore scale because we don't want to effectively scale light radius and range
// by applying those as a view transform to shadow map rendering of objects
let view_backward = transform.back();
let spot_view = spot_light_view_matrix(transform);
let spot_projection = spot_light_projection_matrix(spot_light.outer_angle);
let view_projection = spot_projection * spot_view.inverse();
*frustum = Frustum::from_view_projection(
&view_projection,
&transform.translation(),
&view_backward,
spot_light.range,
);
}
}
pub fn check_light_mesh_visibility(
visible_point_lights: Query<&VisiblePointLights>,
mut point_lights: Query<(
&PointLight,
&GlobalTransform,
&CubemapFrusta,
&mut CubemapVisibleEntities,
Option<&RenderLayers>,
)>,
mut spot_lights: Query<(
&SpotLight,
&GlobalTransform,
&Frustum,
&mut VisibleEntities,
Option<&RenderLayers>,
)>,
mut directional_lights: Query<
(
&DirectionalLight,
&Frustum,
&mut VisibleEntities,
Option<&RenderLayers>,
&ComputedVisibility,
),
Without<SpotLight>,
>,
mut visible_entity_query: Query<
(
Entity,
&mut ComputedVisibility,
Option<&RenderLayers>,
Option<&Aabb>,
Option<&GlobalTransform>,
),
(Without<NotShadowCaster>, Without<DirectionalLight>),
>,
) {
fn shrink_entities(visible_entities: &mut VisibleEntities) {
// Check that visible entities capacity() is no more than two times greater than len()
let capacity = visible_entities.entities.capacity();
let reserved = capacity
.checked_div(visible_entities.entities.len())
.map_or(0, |reserve| {
if reserve > 2 {
capacity / (reserve / 2)
} else {
capacity
}
});
visible_entities.entities.shrink_to(reserved);
}
// Directional lights
for (
directional_light,
frustum,
mut visible_entities,
maybe_view_mask,
light_computed_visibility,
) in &mut directional_lights
{
visible_entities.entities.clear();
// NOTE: If shadow mapping is disabled for the light then it must have no visible entities
if !directional_light.shadows_enabled || !light_computed_visibility.is_visible() {
continue;
}
let view_mask = maybe_view_mask.copied().unwrap_or_default();
for (entity, mut computed_visibility, maybe_entity_mask, maybe_aabb, maybe_transform) in
&mut visible_entity_query
{
if !computed_visibility.is_visible_in_hierarchy() {
continue;
}
let entity_mask = maybe_entity_mask.copied().unwrap_or_default();
if !view_mask.intersects(&entity_mask) {
continue;
}
// If we have an aabb and transform, do frustum culling
if let (Some(aabb), Some(transform)) = (maybe_aabb, maybe_transform) {
if !frustum.intersects_obb(aabb, &transform.compute_matrix(), true) {
continue;
}
}
computed_visibility.set_visible_in_view();
visible_entities.entities.push(entity);
}
shrink_entities(&mut visible_entities);
}
for visible_lights in &visible_point_lights {
for light_entity in visible_lights.entities.iter().copied() {
// Point lights
if let Ok((
point_light,
transform,
cubemap_frusta,
mut cubemap_visible_entities,
maybe_view_mask,
)) = point_lights.get_mut(light_entity)
{
for visible_entities in cubemap_visible_entities.iter_mut() {
visible_entities.entities.clear();
}
// NOTE: If shadow mapping is disabled for the light then it must have no visible entities
if !point_light.shadows_enabled {
continue;
}
let view_mask = maybe_view_mask.copied().unwrap_or_default();
let light_sphere = Sphere {
center: Vec3A::from(transform.translation()),
radius: point_light.range,
};
for (
entity,
mut computed_visibility,
maybe_entity_mask,
maybe_aabb,
maybe_transform,
) in &mut visible_entity_query
{
if !computed_visibility.is_visible_in_hierarchy() {
continue;
}
let entity_mask = maybe_entity_mask.copied().unwrap_or_default();
if !view_mask.intersects(&entity_mask) {
continue;
}
// If we have an aabb and transform, do frustum culling
if let (Some(aabb), Some(transform)) = (maybe_aabb, maybe_transform) {
let model_to_world = transform.compute_matrix();
// Do a cheap sphere vs obb test to prune out most meshes outside the sphere of the light
if !light_sphere.intersects_obb(aabb, &model_to_world) {
continue;
}
for (frustum, visible_entities) in cubemap_frusta
.iter()
.zip(cubemap_visible_entities.iter_mut())
{
if frustum.intersects_obb(aabb, &model_to_world, true) {
computed_visibility.set_visible_in_view();
visible_entities.entities.push(entity);
}
}
} else {
computed_visibility.set_visible_in_view();
for visible_entities in cubemap_visible_entities.iter_mut() {
visible_entities.entities.push(entity);
}
}
}
for visible_entities in cubemap_visible_entities.iter_mut() {
shrink_entities(visible_entities);
}
}
// Spot lights
if let Ok((point_light, transform, frustum, mut visible_entities, maybe_view_mask)) =
spot_lights.get_mut(light_entity)
{
visible_entities.entities.clear();
// NOTE: If shadow mapping is disabled for the light then it must have no visible entities
if !point_light.shadows_enabled {
continue;
}
let view_mask = maybe_view_mask.copied().unwrap_or_default();
let light_sphere = Sphere {
center: Vec3A::from(transform.translation()),
radius: point_light.range,
};
for (
entity,
mut computed_visibility,
maybe_entity_mask,
maybe_aabb,
maybe_transform,
) in visible_entity_query.iter_mut()
{
if !computed_visibility.is_visible_in_hierarchy() {
continue;
}
let entity_mask = maybe_entity_mask.copied().unwrap_or_default();
if !view_mask.intersects(&entity_mask) {
continue;
}
// If we have an aabb and transform, do frustum culling
if let (Some(aabb), Some(transform)) = (maybe_aabb, maybe_transform) {
let model_to_world = transform.compute_matrix();
// Do a cheap sphere vs obb test to prune out most meshes outside the sphere of the light
if !light_sphere.intersects_obb(aabb, &model_to_world) {
continue;
}
if frustum.intersects_obb(aabb, &model_to_world, true) {
computed_visibility.set_visible_in_view();
visible_entities.entities.push(entity);
}
} else {
computed_visibility.set_visible_in_view();
visible_entities.entities.push(entity);
}
}
shrink_entities(&mut visible_entities);
}
}
}
}
#[cfg(test)]
mod test {
use super::*;
fn test_cluster_tiling(config: ClusterConfig, screen_size: UVec2) -> Clusters {
let dims = config.dimensions_for_screen_size(screen_size);
// note: near & far do not affect tiling
let mut clusters = Clusters::default();
clusters.update(screen_size, dims);
// check we cover the screen
assert!(clusters.tile_size.x * clusters.dimensions.x >= screen_size.x);
assert!(clusters.tile_size.y * clusters.dimensions.y >= screen_size.y);
// check a smaller number of clusters would not cover the screen
assert!(clusters.tile_size.x * (clusters.dimensions.x - 1) < screen_size.x);
assert!(clusters.tile_size.y * (clusters.dimensions.y - 1) < screen_size.y);
// check a smaller tilesize would not cover the screen
assert!((clusters.tile_size.x - 1) * clusters.dimensions.x < screen_size.x);
assert!((clusters.tile_size.y - 1) * clusters.dimensions.y < screen_size.y);
// check we don't have more clusters than pixels
assert!(clusters.dimensions.x <= screen_size.x);
assert!(clusters.dimensions.y <= screen_size.y);
clusters
}
#[test]
// check tiling for small screen sizes
fn test_default_cluster_setup_small_screensizes() {
for x in 1..100 {
for y in 1..100 {
let screen_size = UVec2::new(x, y);
let clusters = test_cluster_tiling(ClusterConfig::default(), screen_size);
assert!(
clusters.dimensions.x * clusters.dimensions.y * clusters.dimensions.z <= 4096
);
}
}
}
#[test]
// check tiling for long thin screen sizes
fn test_default_cluster_setup_small_x() {
for x in 1..10 {
for y in 1..5000 {
let screen_size = UVec2::new(x, y);
let clusters = test_cluster_tiling(ClusterConfig::default(), screen_size);
assert!(
clusters.dimensions.x * clusters.dimensions.y * clusters.dimensions.z <= 4096
);
let screen_size = UVec2::new(y, x);
let clusters = test_cluster_tiling(ClusterConfig::default(), screen_size);
assert!(
clusters.dimensions.x * clusters.dimensions.y * clusters.dimensions.z <= 4096
);
}
}
}
}
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