bevy/crates/bevy_pbr/src/light.rs
Kurt Kühnert 701ed8c59f Increase the MAX_DIRECTIONAL_LIGHTS from 1 to 10 (#6066)
# Objective

Currently we are limiting the amount of direction lights in a scene to one.

## Solution

Increase the amount of direction lights from 1 to 10. 
This still is not a perfect solution, but should unblock many use cases.
We could probably just store the directional lights similar to the point lights in an storage buffer, allowing for an variable amount of directional lights.


Co-authored-by: Kurt Kühnert <51823519+Ku95@users.noreply.github.com>
2022-11-03 07:09:51 +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 |
/// | 0.050.3 | Full moon on a clear night |
/// | 3.4 | Dark limit of civil twilight under a clear sky |
/// | 2050 | 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 |
/// | 320500 | Office lighting |
/// | 400 | Sunrise or sunset on a clear day. |
/// | 1000 | Overcast day; typical TV studio lighting |
/// | 10,00025,000 | Full daylight (not direct sun) |
/// | 32,000100,000 | 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 Sousas 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
}
// Sort lights by
// - those with shadows enabled first, so that the index can be used to render at most `directional_light_shadow_maps_count`
// directional light shadows
// - 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 directional_light_order(
(entity_1, shadows_enabled_1): (&Entity, &bool),
(entity_2, shadows_enabled_2): (&Entity, &bool),
) -> std::cmp::Ordering {
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
);
}
}
}
}