bevy/crates/bevy_pbr/src/light.rs
robtfm 5af746457e fix cluster tiling calculations (#4148)
# Objective

fix cluster tilesize and tilecount calculations.
Fixes https://github.com/bevyengine/bevy/issues/4127 & https://github.com/bevyengine/bevy/issues/3596

## Solution

- calculate tilesize as smallest integers such that dimensions.xy() tiles will cover the screen
- calculate final dimensions as smallest integers such that final dimensions * tilesize will cover the screen

there is more cleanup that could be done in these functions. a future PR will likely remove the tilesize completely, so this is just a minimal change set to fix the current bug at small screen sizes

Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2022-03-10 01:14:21 +00:00

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use std::collections::HashSet;
use bevy_asset::Assets;
use bevy_ecs::prelude::*;
use bevy_math::{Mat4, UVec2, UVec3, Vec2, Vec3, Vec3Swizzles, Vec4, Vec4Swizzles};
use bevy_reflect::Reflect;
use bevy_render::{
camera::{Camera, CameraProjection, OrthographicProjection},
color::Color,
prelude::Image,
primitives::{Aabb, CubemapFrusta, Frustum, Sphere},
view::{ComputedVisibility, RenderLayers, Visibility, VisibleEntities},
};
use bevy_transform::components::GlobalTransform;
use bevy_utils::tracing::warn;
use bevy_window::Windows;
use crate::{
calculate_cluster_factors, CubeMapFace, CubemapVisibleEntities, ViewClusterBindings,
CUBE_MAP_FACES, MAX_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)]
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(Clone, Debug)]
pub struct PointLightShadowMap {
pub size: usize,
}
impl Default for PointLightShadowMap {
fn default() -> Self {
Self { size: 1024 }
}
}
/// A Directional light.
///
/// Directional lights don't exist in reality but they are a good
/// approximation for light sources VERY far away, like the sun or
/// the moon.
///
/// Valid values for `illuminance` are:
///
/// | Illuminance (lux) | Surfaces illuminated by |
/// |-------------------|------------------------------------------------|
/// | 0.0001 | Moonless, overcast night sky (starlight) |
/// | 0.002 | Moonless clear night sky with airglow |
/// | 0.050.3 | 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)]
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(Clone, Debug)]
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(Debug)]
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)]
pub struct NotShadowCaster;
/// Add this component to make a [`Mesh`](bevy_render::mesh::Mesh) not receive shadows.
#[derive(Component)]
pub struct NotShadowReceiver;
#[derive(Debug, Hash, PartialEq, Eq, Clone, SystemLabel)]
pub enum SimulationLightSystems {
AddClusters,
AssignLightsToClusters,
UpdateDirectionalLightFrusta,
UpdatePointLightFrusta,
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 {
/// Use the camera far-plane to determine the z-depth of the furthest cluster layer
CameraFarPlane,
/// 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 => 0.0,
ClusterConfig::Single => 1.0e9, // FIXME note can't use f32::MAX as the aabb explodes
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::Constant(1.0e9), // FIXME note can't use f32::MAX as the aabb explodes
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)]
pub struct Clusters {
/// Tile size
pub(crate) tile_size: UVec2,
/// Number of clusters in x / y / z in the view frustum
pub(crate) axis_slices: 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,
aabbs: Vec<Aabb>,
pub(crate) lights: Vec<VisiblePointLights>,
}
impl Clusters {
fn new(tile_size: UVec2, screen_size: UVec2, z_slices: u32, near: f32, far: f32) -> Self {
let mut clusters = Self {
tile_size,
axis_slices: Default::default(),
near,
far,
aabbs: Default::default(),
lights: Default::default(),
};
clusters.update(tile_size, screen_size, z_slices);
clusters
}
fn from_screen_size_and_dimensions(
screen_size: UVec2,
dimensions: UVec3,
near: f32,
far: f32,
) -> Self {
debug_assert!(screen_size.x > 0 && screen_size.y > 0);
debug_assert!(dimensions.x > 0 && dimensions.y > 0 && dimensions.z > 0);
Clusters::new(
(screen_size.as_vec2() / dimensions.xy().as_vec2())
.ceil()
.as_uvec2(),
screen_size,
dimensions.z,
near,
far,
)
}
fn update(&mut self, tile_size: UVec2, screen_size: UVec2, z_slices: u32) {
self.tile_size = tile_size;
self.axis_slices = (screen_size.as_vec2() / tile_size.as_vec2())
.ceil()
.as_uvec2()
.extend(z_slices);
// NOTE: Maximum 4096 clusters due to uniform buffer size constraints
debug_assert!(self.axis_slices.x * self.axis_slices.y * self.axis_slices.z <= 4096);
}
}
fn clip_to_view(inverse_projection: Mat4, clip: Vec4) -> Vec4 {
let view = inverse_projection * clip;
view / view.w
}
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)
}
// 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)
}
pub fn add_clusters(
mut commands: Commands,
cameras: Query<(Entity, Option<&ClusterConfig>), (With<Camera>, Without<Clusters>)>,
) {
for (entity, config) in cameras.iter() {
let config = config.copied().unwrap_or_default();
// actual settings here don't matter - they will be overwritten in assign_lights_to_clusters
let clusters = Clusters::from_screen_size_and_dimensions(UVec2::ONE, UVec3::ONE, 1.0, 1.0);
commands.entity(entity).insert_bundle((clusters, config));
}
}
fn update_clusters(
screen_size: UVec2,
camera: &Camera,
cluster_dimensions: UVec3,
clusters: &mut Clusters,
near: f32,
far: f32,
) {
let is_orthographic = camera.projection_matrix.w_axis.w == 1.0;
let inverse_projection = camera.projection_matrix.inverse();
// Don't update clusters if screen size is 0.
if screen_size.x == 0 || screen_size.y == 0 {
return;
}
*clusters =
Clusters::from_screen_size_and_dimensions(screen_size, cluster_dimensions, near, far);
let screen_size = screen_size.as_vec2();
let tile_size_u32 = clusters.tile_size;
let tile_size = tile_size_u32.as_vec2();
// Calculate view space AABBs
// NOTE: It is important that these are iterated in a specific order
// so that we can calculate the cluster index in the fragment shader!
// I (Rob Swain) choose to scan along rows of tiles in x,y, and for each tile then scan
// along z
let mut aabbs = Vec::with_capacity(
(clusters.axis_slices.y * clusters.axis_slices.x * clusters.axis_slices.z) as usize,
);
for y in 0..clusters.axis_slices.y {
for x in 0..clusters.axis_slices.x {
for z in 0..clusters.axis_slices.z {
aabbs.push(compute_aabb_for_cluster(
near,
far,
tile_size,
screen_size,
inverse_projection,
is_orthographic,
clusters.axis_slices,
UVec3::new(x, y, z),
));
}
}
}
clusters.aabbs = aabbs;
}
#[derive(Clone, Component, Debug, Default)]
pub struct VisiblePointLights {
pub entities: Vec<Entity>,
}
impl VisiblePointLights {
pub fn from_light_count(count: usize) -> Self {
Self {
entities: Vec::with_capacity(count),
}
}
pub fn iter(&self) -> impl DoubleEndedIterator<Item = &Entity> {
self.entities.iter()
}
pub fn len(&self) -> usize {
self.entities.len()
}
pub fn is_empty(&self) -> bool {
self.entities.is_empty()
}
}
fn view_z_to_z_slice(
cluster_factors: Vec2,
z_slices: f32,
view_z: f32,
is_orthographic: bool,
) -> u32 {
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).clamp(0.0, z_slices - 1.0)
as u32
}
}
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::new(0.5, -0.5) + Vec2::splat(0.5)).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 as f32,
view_z,
is_orthographic,
);
xy.as_uvec2()
.extend(z_slice)
.clamp(UVec3::ZERO, cluster_dimensions - UVec3::ONE)
}
// Calculate bounds for the light using a view space aabb.
// Returns a (Vec3, Vec3) containing min and max 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: (inverse_view_transform * light_sphere.center.extend(1.0)).xyz(),
half_extents: Vec3::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),
);
// pack unadjusted z depth into the vecs
let (aabb_min, aabb_max) = (
light_aabb_ndc_min.xy().extend(light_aabb_view_min.z),
light_aabb_ndc_max.xy().extend(light_aabb_view_max.z),
);
// clamp to ndc coords
(
aabb_min.clamp(
Vec3::new(-1.0, -1.0, f32::MIN),
Vec3::new(1.0, 1.0, f32::MAX),
),
aabb_max.clamp(
Vec3::new(-1.0, -1.0, f32::MIN),
Vec3::new(1.0, 1.0, f32::MAX),
),
)
}
// Sort point lights with shadows enabled first, then by a stable key so that the index
// can be used to render at most `MAX_POINT_LIGHT_SHADOW_MAPS` point light shadows and
// we keep a stable set of lights visible
pub(crate) fn point_light_order(
(entity_1, shadows_enabled_1): (&Entity, &bool),
(entity_2, shadows_enabled_2): (&Entity, &bool),
) -> std::cmp::Ordering {
shadows_enabled_1
.cmp(shadows_enabled_2)
.reverse()
.then_with(|| entity_1.cmp(entity_2))
}
#[derive(Clone, Copy)]
// data required for assigning lights to clusters
pub(crate) struct PointLightAssignmentData {
entity: Entity,
translation: Vec3,
range: f32,
shadows_enabled: bool,
}
// 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<VisiblePointLights>,
windows: Res<Windows>,
images: Res<Assets<Image>>,
mut views: Query<(
Entity,
&GlobalTransform,
&Camera,
&Frustum,
&ClusterConfig,
&mut Clusters,
)>,
lights_query: Query<(Entity, &GlobalTransform, &PointLight, &Visibility)>,
mut lights: Local<Vec<PointLightAssignmentData>>,
mut max_point_lights_warning_emitted: Local<bool>,
) {
// collect just the relevant light query data into a persisted vec to avoid reallocating each frame
lights.extend(
lights_query
.iter()
.filter(|(.., visibility)| visibility.is_visible)
.map(
|(entity, transform, light, _visibility)| PointLightAssignmentData {
entity,
translation: transform.translation,
shadows_enabled: light.shadows_enabled,
range: light.range,
},
),
);
if lights.len() > MAX_POINT_LIGHTS {
lights.sort_by(|light_1, light_2| {
point_light_order(
(&light_1.entity, &light_1.shadows_enabled),
(&light_2.entity, &light_2.shadows_enabled),
)
});
// 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_POINT_LIGHTS + 1 {
false
} else {
let light_sphere = Sphere {
center: light.translation,
radius: light.range,
};
let light_in_view = frusta
.iter()
.any(|frustum| frustum.intersects_sphere(&light_sphere));
if light_in_view {
lights_in_view_count += 1;
}
light_in_view
}
});
if lights.len() > MAX_POINT_LIGHTS && !*max_point_lights_warning_emitted {
warn!("MAX_POINT_LIGHTS ({}) exceeded", MAX_POINT_LIGHTS);
*max_point_lights_warning_emitted = true;
}
lights.truncate(MAX_POINT_LIGHTS);
}
let light_count = lights.len();
let mut global_lights_set = HashSet::with_capacity(light_count);
for (view_entity, view_transform, camera, frustum, config, mut clusters) in views.iter_mut() {
if matches!(config, ClusterConfig::None) {
commands.entity(view_entity).remove::<VisiblePointLights>();
continue;
}
let view_transform = view_transform.compute_matrix();
let inverse_view_transform = view_transform.inverse();
let is_orthographic = camera.projection_matrix.w_axis.w == 1.0;
let screen_size_u32 = camera.target.get_physical_size(&windows, &images);
let screen_size_u32 = screen_size_u32.unwrap_or_default();
if screen_size_u32.x == 0 || screen_size_u32.y == 0 {
continue;
}
let mut cluster_dimensions = config.dimensions_for_screen_size(screen_size_u32);
let far_z = match config.far_z_mode() {
ClusterFarZMode::CameraFarPlane => camera.far,
ClusterFarZMode::MaxLightRange => {
let inverse_view_row_2 = inverse_view_transform.row(2);
lights
.iter()
.map(|light| {
-inverse_view_row_2.dot(light.translation.extend(1.0)) + light.range
})
.reduce(f32::max)
.unwrap_or(0.0)
}
ClusterFarZMode::Constant(far) => far,
};
let first_slice_depth = match cluster_dimensions.z {
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,
cluster_dimensions.z as f32,
is_orthographic,
);
let max_indices = ViewClusterBindings::MAX_INDICES;
if config.dynamic_resizing() {
let mut cluster_index_estimate = 0.0;
for light in lights.iter() {
let light_sphere = Sphere {
center: light.translation,
radius: light.range,
};
// Check if the light is within the view frustum
if !frustum.intersects_sphere(&light_sphere) {
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,
cluster_dimensions.z as f32,
light_aabb_min.z,
is_orthographic,
);
let z_cluster_max = view_z_to_z_slice(
cluster_factors,
cluster_dimensions.z as f32,
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(cluster_dimensions.x as f32, 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 > 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 = max_indices as f32 / cluster_index_estimate as f32;
let xy_ratio = index_ratio.sqrt();
cluster_dimensions.x =
((cluster_dimensions.x as f32 * xy_ratio).floor() as u32).max(1);
cluster_dimensions.y =
((cluster_dimensions.y as f32 * xy_ratio).floor() as u32).max(1);
}
}
update_clusters(
screen_size_u32,
camera,
cluster_dimensions,
&mut clusters,
first_slice_depth,
far_z,
);
// NOTE: This is here to avoid bugs in future due to update_clusters() having updated clusters.axis_slices
// but cluster_dimensions has a different configuration.
#[allow(unused_assignments)]
{
cluster_dimensions = clusters.axis_slices;
}
let cluster_count = clusters.aabbs.len();
let mut clusters_lights =
vec![VisiblePointLights::from_light_count(light_count); cluster_count];
let mut visible_lights = Vec::with_capacity(light_count);
for light in lights.iter() {
let light_sphere = Sphere {
center: light.translation,
radius: light.range,
};
// Check if the light is within the view frustum
if !frustum.intersects_sphere(&light_sphere) {
continue;
}
// NOTE: The light intersects the frustum so it must be visible and part of the global set
global_lights_set.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.axis_slices,
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.axis_slices,
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));
for y in min_cluster.y..=max_cluster.y {
let row_offset = y * clusters.axis_slices.x;
for x in min_cluster.x..=max_cluster.x {
let col_offset = (row_offset + x) * clusters.axis_slices.z;
for z in min_cluster.z..=max_cluster.z {
// NOTE: cluster_index = (y * dim.x + x) * dim.z + z
let cluster_index = (col_offset + z) as usize;
let cluster_aabb = &clusters.aabbs[cluster_index];
if light_sphere.intersects_obb(cluster_aabb, &view_transform) {
clusters_lights[cluster_index].entities.push(light.entity);
}
}
}
}
}
for cluster_lights in &mut clusters_lights {
cluster_lights.entities.shrink_to_fit();
}
clusters.lights = clusters_lights;
visible_lights.shrink_to_fit();
commands.entity(view_entity).insert(VisiblePointLights {
entities: visible_lights,
});
}
global_lights.entities = global_lights_set.into_iter().collect();
lights.clear();
}
pub fn update_directional_light_frusta(
mut views: Query<
(
&GlobalTransform,
&DirectionalLight,
&mut Frustum,
&Visibility,
),
Or<(Changed<GlobalTransform>, Changed<DirectionalLight>)>,
>,
) {
for (transform, directional_light, mut frustum, visibility) in views.iter_mut() {
// 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<VisiblePointLights>,
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 }| GlobalTransform::identity().looking_at(*target, *up))
.collect::<Vec<_>>();
let global_lights_set = global_lights
.entities
.iter()
.copied()
.collect::<HashSet<_>>();
for (entity, transform, point_light, mut cubemap_frusta) 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 !point_light.shadows_enabled || !global_lights_set.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 = GlobalTransform::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 check_light_mesh_visibility(
visible_point_lights: Query<&VisiblePointLights>,
mut point_lights: Query<(
&PointLight,
&GlobalTransform,
&CubemapFrusta,
&mut CubemapVisibleEntities,
Option<&RenderLayers>,
)>,
mut directional_lights: Query<(
&DirectionalLight,
&Frustum,
&mut VisibleEntities,
Option<&RenderLayers>,
&Visibility,
)>,
mut visible_entity_query: Query<
(
Entity,
&Visibility,
&mut ComputedVisibility,
Option<&RenderLayers>,
Option<&Aabb>,
Option<&GlobalTransform>,
),
Without<NotShadowCaster>,
>,
) {
// Directonal lights
for (directional_light, frustum, mut visible_entities, maybe_view_mask, visibility) in
directional_lights.iter_mut()
{
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 || !visibility.is_visible {
continue;
}
let view_mask = maybe_view_mask.copied().unwrap_or_default();
for (
entity,
visibility,
mut computed_visibility,
maybe_entity_mask,
maybe_aabb,
maybe_transform,
) in visible_entity_query.iter_mut()
{
if !visibility.is_visible {
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()) {
continue;
}
}
computed_visibility.is_visible = true;
visible_entities.entities.push(entity);
}
// TODO: check for big changes in visible entities len() vs capacity() (ex: 2x) and resize
// to prevent holding unneeded memory
}
// Point lights
for visible_lights in visible_point_lights.iter() {
for light_entity in visible_lights.entities.iter().copied() {
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: transform.translation,
radius: point_light.range,
};
for (
entity,
visibility,
mut computed_visibility,
maybe_entity_mask,
maybe_aabb,
maybe_transform,
) in visible_entity_query.iter_mut()
{
if !visibility.is_visible {
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) {
computed_visibility.is_visible = true;
visible_entities.entities.push(entity);
}
}
} else {
computed_visibility.is_visible = true;
for visible_entities in cubemap_visible_entities.iter_mut() {
visible_entities.entities.push(entity);
}
}
}
// TODO: check for big changes in visible entities len() vs capacity() (ex: 2x) and resize
// to prevent holding unneeded memory
}
}
}
}
#[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 clusters = Clusters::from_screen_size_and_dimensions(screen_size, dims, 5.0, 1000.0);
// check we cover the screen
assert!(clusters.tile_size.x * clusters.axis_slices.x >= screen_size.x);
assert!(clusters.tile_size.y * clusters.axis_slices.y >= screen_size.y);
// check a smaller number of clusters would not cover the screen
assert!(clusters.tile_size.x * (clusters.axis_slices.x - 1) < screen_size.x);
assert!(clusters.tile_size.y * (clusters.axis_slices.y - 1) < screen_size.y);
// check a smaller tilesize would not cover the screen
assert!((clusters.tile_size.x - 1) * clusters.axis_slices.x < screen_size.x);
assert!((clusters.tile_size.y - 1) * clusters.axis_slices.y < screen_size.y);
// check we don't have more clusters than pixels
assert!(clusters.axis_slices.x <= screen_size.x);
assert!(clusters.axis_slices.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.axis_slices.x * clusters.axis_slices.y * clusters.axis_slices.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.axis_slices.x * clusters.axis_slices.y * clusters.axis_slices.z
<= 4096
);
let screen_size = UVec2::new(y, x);
let clusters = test_cluster_tiling(ClusterConfig::default(), screen_size);
assert!(
clusters.axis_slices.x * clusters.axis_slices.y * clusters.axis_slices.z
<= 4096
);
}
}
}
}