mirror of
https://github.com/bevyengine/bevy
synced 2024-11-25 22:20:20 +00:00
Separate out PBR lighting, shadows, clustered forward, and utils from pbr.wgsl (#4938)
# Objective - Builds on top of #4901 - Separate out PBR lighting, shadows, clustered forward, and utils from `pbr.wgsl` as part of making the PBR code more reusable and extensible. - See #3969 for details. ## Solution - Add `bevy_pbr::utils`, `bevy_pbr::clustered_forward`, `bevy_pbr::lighting`, `bevy_pbr::shadows` shader imports exposing many shader functions for external use - Split `PI`, `saturate()`, `hsv2rgb()`, and `random1D()` into `bevy_pbr::utils` - Split clustered-forward-specific functions into `bevy_pbr::clustered_forward`, including moving the debug visualization code into a `cluster_debug_visualization()` function in that import - Split PBR lighting functions into `bevy_pbr::lighting` - Split shadow functions into `bevy_pbr::shadows` --- ## Changelog - Added: `bevy_pbr::utils`, `bevy_pbr::clustered_forward`, `bevy_pbr::lighting`, `bevy_pbr::shadows` shader imports exposing many shader functions for external use - Split `PI`, `saturate()`, `hsv2rgb()`, and `random1D()` into `bevy_pbr::utils` - Split clustered-forward-specific functions into `bevy_pbr::clustered_forward`, including moving the debug visualization code into a `cluster_debug_visualization()` function in that import - Split PBR lighting functions into `bevy_pbr::lighting` - Split shadow functions into `bevy_pbr::shadows`
This commit is contained in:
Robert Swain
parent
b333386271
commit
c6222f1acc
6 changed files with 492 additions and 438 deletions
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@ -54,6 +54,14 @@ pub const PBR_TYPES_SHADER_HANDLE: HandleUntyped =
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HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 1708015359337029744);
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pub const PBR_BINDINGS_SHADER_HANDLE: HandleUntyped =
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HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 5635987986427308186);
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pub const UTILS_HANDLE: HandleUntyped =
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HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 1900548483293416725);
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pub const CLUSTERED_FORWARD_HANDLE: HandleUntyped =
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HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 166852093121196815);
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pub const PBR_LIGHTING_HANDLE: HandleUntyped =
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HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 14170772752254856967);
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pub const SHADOWS_HANDLE: HandleUntyped =
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HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 11350275143789590502);
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pub const PBR_SHADER_HANDLE: HandleUntyped =
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HandleUntyped::weak_from_u64(Shader::TYPE_UUID, 4805239651767701046);
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pub const SHADOW_SHADER_HANDLE: HandleUntyped =
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@ -77,6 +85,25 @@ impl Plugin for PbrPlugin {
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"render/pbr_bindings.wgsl",
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Shader::from_wgsl
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);
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load_internal_asset!(app, UTILS_HANDLE, "render/utils.wgsl", Shader::from_wgsl);
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load_internal_asset!(
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app,
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CLUSTERED_FORWARD_HANDLE,
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"render/clustered_forward.wgsl",
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Shader::from_wgsl
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);
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load_internal_asset!(
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app,
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PBR_LIGHTING_HANDLE,
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"render/pbr_lighting.wgsl",
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Shader::from_wgsl
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);
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load_internal_asset!(
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app,
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SHADOWS_HANDLE,
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"render/shadows.wgsl",
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Shader::from_wgsl
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);
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load_internal_asset!(app, PBR_SHADER_HANDLE, "render/pbr.wgsl", Shader::from_wgsl);
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load_internal_asset!(
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app,
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100
crates/bevy_pbr/src/render/clustered_forward.wgsl
Normal file
100
crates/bevy_pbr/src/render/clustered_forward.wgsl
Normal file
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@ -0,0 +1,100 @@
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#define_import_path bevy_pbr::clustered_forward
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// NOTE: Keep in sync with bevy_pbr/src/light.rs
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fn view_z_to_z_slice(view_z: f32, is_orthographic: bool) -> u32 {
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var z_slice: u32 = 0u;
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if (is_orthographic) {
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// NOTE: view_z is correct in the orthographic case
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z_slice = u32(floor((view_z - lights.cluster_factors.z) * lights.cluster_factors.w));
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} else {
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// NOTE: had to use -view_z to make it positive else log(negative) is nan
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z_slice = u32(log(-view_z) * lights.cluster_factors.z - lights.cluster_factors.w + 1.0);
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}
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// NOTE: We use min as we may limit the far z plane used for clustering to be closeer than
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// the furthest thing being drawn. This means that we need to limit to the maximum cluster.
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return min(z_slice, lights.cluster_dimensions.z - 1u);
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}
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fn fragment_cluster_index(frag_coord: vec2<f32>, view_z: f32, is_orthographic: bool) -> u32 {
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let xy = vec2<u32>(floor(frag_coord * lights.cluster_factors.xy));
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let z_slice = view_z_to_z_slice(view_z, is_orthographic);
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// NOTE: Restricting cluster index to avoid undefined behavior when accessing uniform buffer
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// arrays based on the cluster index.
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return min(
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(xy.y * lights.cluster_dimensions.x + xy.x) * lights.cluster_dimensions.z + z_slice,
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lights.cluster_dimensions.w - 1u
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);
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}
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// this must match CLUSTER_COUNT_SIZE in light.rs
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let CLUSTER_COUNT_SIZE = 13u;
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fn unpack_offset_and_count(cluster_index: u32) -> vec2<u32> {
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#ifdef NO_STORAGE_BUFFERS_SUPPORT
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let offset_and_count = cluster_offsets_and_counts.data[cluster_index >> 2u][cluster_index & ((1u << 2u) - 1u)];
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return vec2<u32>(
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// The offset is stored in the upper 32 - CLUSTER_COUNT_SIZE = 19 bits
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(offset_and_count >> CLUSTER_COUNT_SIZE) & ((1u << 32u - CLUSTER_COUNT_SIZE) - 1u),
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// The count is stored in the lower CLUSTER_COUNT_SIZE = 13 bits
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offset_and_count & ((1u << CLUSTER_COUNT_SIZE) - 1u)
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);
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#else
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return cluster_offsets_and_counts.data[cluster_index];
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#endif
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}
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fn get_light_id(index: u32) -> u32 {
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#ifdef NO_STORAGE_BUFFERS_SUPPORT
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// The index is correct but in cluster_light_index_lists we pack 4 u8s into a u32
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// This means the index into cluster_light_index_lists is index / 4
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let indices = cluster_light_index_lists.data[index >> 4u][(index >> 2u) & ((1u << 2u) - 1u)];
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// And index % 4 gives the sub-index of the u8 within the u32 so we shift by 8 * sub-index
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return (indices >> (8u * (index & ((1u << 2u) - 1u)))) & ((1u << 8u) - 1u);
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#else
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return cluster_light_index_lists.data[index];
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#endif
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}
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fn cluster_debug_visualization(
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output_color: vec4<f32>,
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view_z: f32,
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is_orthographic: bool,
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offset_and_count: vec2<u32>,
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cluster_index: u32,
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) -> vec4<f32> {
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// Cluster allocation debug (using 'over' alpha blending)
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#ifdef CLUSTERED_FORWARD_DEBUG_Z_SLICES
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// NOTE: This debug mode visualises the z-slices
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let cluster_overlay_alpha = 0.1;
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var z_slice: u32 = view_z_to_z_slice(view_z, is_orthographic);
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// A hack to make the colors alternate a bit more
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if ((z_slice & 1u) == 1u) {
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z_slice = z_slice + lights.cluster_dimensions.z / 2u;
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}
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let slice_color = hsv2rgb(f32(z_slice) / f32(lights.cluster_dimensions.z + 1u), 1.0, 0.5);
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output_color = vec4<f32>(
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(1.0 - cluster_overlay_alpha) * output_color.rgb + cluster_overlay_alpha * slice_color,
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output_color.a
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);
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#endif // CLUSTERED_FORWARD_DEBUG_Z_SLICES
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#ifdef CLUSTERED_FORWARD_DEBUG_CLUSTER_LIGHT_COMPLEXITY
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// NOTE: This debug mode visualises the number of lights within the cluster that contains
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// the fragment. It shows a sort of lighting complexity measure.
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let cluster_overlay_alpha = 0.1;
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let max_light_complexity_per_cluster = 64.0;
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output_color.r = (1.0 - cluster_overlay_alpha) * output_color.r
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+ cluster_overlay_alpha * smoothStep(0.0, max_light_complexity_per_cluster, f32(offset_and_count[1]));
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output_color.g = (1.0 - cluster_overlay_alpha) * output_color.g
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+ cluster_overlay_alpha * (1.0 - smoothStep(0.0, max_light_complexity_per_cluster, f32(offset_and_count[1])));
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#endif // CLUSTERED_FORWARD_DEBUG_CLUSTER_LIGHT_COMPLEXITY
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#ifdef CLUSTERED_FORWARD_DEBUG_CLUSTER_COHERENCY
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// NOTE: Visualizes the cluster to which the fragment belongs
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let cluster_overlay_alpha = 0.1;
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let cluster_color = hsv2rgb(random1D(f32(cluster_index)), 1.0, 0.5);
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output_color = vec4<f32>(
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(1.0 - cluster_overlay_alpha) * output_color.rgb + cluster_overlay_alpha * cluster_color,
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output_color.a
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);
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#endif // CLUSTERED_FORWARD_DEBUG_CLUSTER_COHERENCY
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return output_color;
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}
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@ -1,412 +1,11 @@
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// From the Filament design doc
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// https://google.github.io/filament/Filament.html#table_symbols
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// Symbol Definition
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// v View unit vector
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// l Incident light unit vector
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// n Surface normal unit vector
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// h Half unit vector between l and v
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// f BRDF
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// f_d Diffuse component of a BRDF
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// f_r Specular component of a BRDF
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// α Roughness, remapped from using input perceptualRoughness
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// σ Diffuse reflectance
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// Ω Spherical domain
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// f0 Reflectance at normal incidence
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// f90 Reflectance at grazing angle
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// χ+(a) Heaviside function (1 if a>0 and 0 otherwise)
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// nior Index of refraction (IOR) of an interface
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// ⟨n⋅l⟩ Dot product clamped to [0..1]
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// ⟨a⟩ Saturated value (clamped to [0..1])
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// The Bidirectional Reflectance Distribution Function (BRDF) describes the surface response of a standard material
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// and consists of two components, the diffuse component (f_d) and the specular component (f_r):
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// f(v,l) = f_d(v,l) + f_r(v,l)
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//
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// The form of the microfacet model is the same for diffuse and specular
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// f_r(v,l) = f_d(v,l) = 1 / { |n⋅v||n⋅l| } ∫_Ω D(m,α) G(v,l,m) f_m(v,l,m) (v⋅m) (l⋅m) dm
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//
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// In which:
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// D, also called the Normal Distribution Function (NDF) models the distribution of the microfacets
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// G models the visibility (or occlusion or shadow-masking) of the microfacets
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// f_m is the microfacet BRDF and differs between specular and diffuse components
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//
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// The above integration needs to be approximated.
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#import bevy_pbr::mesh_view_bindings
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#import bevy_pbr::pbr_bindings
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#import bevy_pbr::mesh_bindings
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let PI: f32 = 3.141592653589793;
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fn saturate(value: f32) -> f32 {
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return clamp(value, 0.0, 1.0);
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}
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// distanceAttenuation is simply the square falloff of light intensity
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// combined with a smooth attenuation at the edge of the light radius
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//
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// light radius is a non-physical construct for efficiency purposes,
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// because otherwise every light affects every fragment in the scene
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fn getDistanceAttenuation(distanceSquare: f32, inverseRangeSquared: f32) -> f32 {
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let factor = distanceSquare * inverseRangeSquared;
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let smoothFactor = saturate(1.0 - factor * factor);
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let attenuation = smoothFactor * smoothFactor;
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return attenuation * 1.0 / max(distanceSquare, 0.0001);
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}
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// Normal distribution function (specular D)
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// Based on https://google.github.io/filament/Filament.html#citation-walter07
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// D_GGX(h,α) = α^2 / { π ((n⋅h)^2 (α2−1) + 1)^2 }
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// Simple implementation, has precision problems when using fp16 instead of fp32
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// see https://google.github.io/filament/Filament.html#listing_speculardfp16
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fn D_GGX(roughness: f32, NoH: f32, h: vec3<f32>) -> f32 {
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let oneMinusNoHSquared = 1.0 - NoH * NoH;
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let a = NoH * roughness;
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let k = roughness / (oneMinusNoHSquared + a * a);
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let d = k * k * (1.0 / PI);
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return d;
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}
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// Visibility function (Specular G)
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// V(v,l,a) = G(v,l,α) / { 4 (n⋅v) (n⋅l) }
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// such that f_r becomes
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// f_r(v,l) = D(h,α) V(v,l,α) F(v,h,f0)
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// where
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// V(v,l,α) = 0.5 / { n⋅l sqrt((n⋅v)^2 (1−α2) + α2) + n⋅v sqrt((n⋅l)^2 (1−α2) + α2) }
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// Note the two sqrt's, that may be slow on mobile, see https://google.github.io/filament/Filament.html#listing_approximatedspecularv
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fn V_SmithGGXCorrelated(roughness: f32, NoV: f32, NoL: f32) -> f32 {
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let a2 = roughness * roughness;
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let lambdaV = NoL * sqrt((NoV - a2 * NoV) * NoV + a2);
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let lambdaL = NoV * sqrt((NoL - a2 * NoL) * NoL + a2);
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let v = 0.5 / (lambdaV + lambdaL);
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return v;
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}
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// Fresnel function
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// see https://google.github.io/filament/Filament.html#citation-schlick94
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// F_Schlick(v,h,f_0,f_90) = f_0 + (f_90 − f_0) (1 − v⋅h)^5
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fn F_Schlick_vec(f0: vec3<f32>, f90: f32, VoH: f32) -> vec3<f32> {
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// not using mix to keep the vec3 and float versions identical
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return f0 + (f90 - f0) * pow(1.0 - VoH, 5.0);
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}
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fn F_Schlick(f0: f32, f90: f32, VoH: f32) -> f32 {
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// not using mix to keep the vec3 and float versions identical
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return f0 + (f90 - f0) * pow(1.0 - VoH, 5.0);
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}
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fn fresnel(f0: vec3<f32>, LoH: f32) -> vec3<f32> {
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// f_90 suitable for ambient occlusion
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// see https://google.github.io/filament/Filament.html#lighting/occlusion
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let f90 = saturate(dot(f0, vec3<f32>(50.0 * 0.33)));
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return F_Schlick_vec(f0, f90, LoH);
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}
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// Specular BRDF
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// https://google.github.io/filament/Filament.html#materialsystem/specularbrdf
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// Cook-Torrance approximation of the microfacet model integration using Fresnel law F to model f_m
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// f_r(v,l) = { D(h,α) G(v,l,α) F(v,h,f0) } / { 4 (n⋅v) (n⋅l) }
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fn specular(f0: vec3<f32>, roughness: f32, h: vec3<f32>, NoV: f32, NoL: f32,
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NoH: f32, LoH: f32, specularIntensity: f32) -> vec3<f32> {
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let D = D_GGX(roughness, NoH, h);
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let V = V_SmithGGXCorrelated(roughness, NoV, NoL);
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let F = fresnel(f0, LoH);
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return (specularIntensity * D * V) * F;
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}
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// Diffuse BRDF
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// https://google.github.io/filament/Filament.html#materialsystem/diffusebrdf
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// fd(v,l) = σ/π * 1 / { |n⋅v||n⋅l| } ∫Ω D(m,α) G(v,l,m) (v⋅m) (l⋅m) dm
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//
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// simplest approximation
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// float Fd_Lambert() {
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// return 1.0 / PI;
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// }
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//
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// vec3 Fd = diffuseColor * Fd_Lambert();
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//
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// Disney approximation
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// See https://google.github.io/filament/Filament.html#citation-burley12
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// minimal quality difference
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fn Fd_Burley(roughness: f32, NoV: f32, NoL: f32, LoH: f32) -> f32 {
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let f90 = 0.5 + 2.0 * roughness * LoH * LoH;
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let lightScatter = F_Schlick(1.0, f90, NoL);
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let viewScatter = F_Schlick(1.0, f90, NoV);
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return lightScatter * viewScatter * (1.0 / PI);
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}
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// From https://www.unrealengine.com/en-US/blog/physically-based-shading-on-mobile
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fn EnvBRDFApprox(f0: vec3<f32>, perceptual_roughness: f32, NoV: f32) -> vec3<f32> {
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let c0 = vec4<f32>(-1.0, -0.0275, -0.572, 0.022);
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let c1 = vec4<f32>(1.0, 0.0425, 1.04, -0.04);
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let r = perceptual_roughness * c0 + c1;
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let a004 = min(r.x * r.x, exp2(-9.28 * NoV)) * r.x + r.y;
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let AB = vec2<f32>(-1.04, 1.04) * a004 + r.zw;
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return f0 * AB.x + AB.y;
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}
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fn perceptualRoughnessToRoughness(perceptualRoughness: f32) -> f32 {
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// clamp perceptual roughness to prevent precision problems
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// According to Filament design 0.089 is recommended for mobile
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// Filament uses 0.045 for non-mobile
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let clampedPerceptualRoughness = clamp(perceptualRoughness, 0.089, 1.0);
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return clampedPerceptualRoughness * clampedPerceptualRoughness;
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}
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// from https://64.github.io/tonemapping/
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// reinhard on RGB oversaturates colors
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fn reinhard(color: vec3<f32>) -> vec3<f32> {
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return color / (1.0 + color);
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}
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fn reinhard_extended(color: vec3<f32>, max_white: f32) -> vec3<f32> {
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let numerator = color * (1.0 + (color / vec3<f32>(max_white * max_white)));
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return numerator / (1.0 + color);
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}
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// luminance coefficients from Rec. 709.
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// https://en.wikipedia.org/wiki/Rec._709
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fn luminance(v: vec3<f32>) -> f32 {
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return dot(v, vec3<f32>(0.2126, 0.7152, 0.0722));
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}
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fn change_luminance(c_in: vec3<f32>, l_out: f32) -> vec3<f32> {
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let l_in = luminance(c_in);
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return c_in * (l_out / l_in);
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}
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fn reinhard_luminance(color: vec3<f32>) -> vec3<f32> {
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let l_old = luminance(color);
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let l_new = l_old / (1.0 + l_old);
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return change_luminance(color, l_new);
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}
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|
||||
fn reinhard_extended_luminance(color: vec3<f32>, max_white_l: f32) -> vec3<f32> {
|
||||
let l_old = luminance(color);
|
||||
let numerator = l_old * (1.0 + (l_old / (max_white_l * max_white_l)));
|
||||
let l_new = numerator / (1.0 + l_old);
|
||||
return change_luminance(color, l_new);
|
||||
}
|
||||
|
||||
// NOTE: Keep in sync with bevy_pbr/src/light.rs
|
||||
fn view_z_to_z_slice(view_z: f32, is_orthographic: bool) -> u32 {
|
||||
var z_slice: u32 = 0u;
|
||||
if (is_orthographic) {
|
||||
// NOTE: view_z is correct in the orthographic case
|
||||
z_slice = u32(floor((view_z - lights.cluster_factors.z) * lights.cluster_factors.w));
|
||||
} else {
|
||||
// NOTE: had to use -view_z to make it positive else log(negative) is nan
|
||||
z_slice = u32(log(-view_z) * lights.cluster_factors.z - lights.cluster_factors.w + 1.0);
|
||||
}
|
||||
// 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.
|
||||
return min(z_slice, lights.cluster_dimensions.z - 1u);
|
||||
}
|
||||
|
||||
fn fragment_cluster_index(frag_coord: vec2<f32>, view_z: f32, is_orthographic: bool) -> u32 {
|
||||
let xy = vec2<u32>(floor(frag_coord * lights.cluster_factors.xy));
|
||||
let z_slice = view_z_to_z_slice(view_z, is_orthographic);
|
||||
// NOTE: Restricting cluster index to avoid undefined behavior when accessing uniform buffer
|
||||
// arrays based on the cluster index.
|
||||
return min(
|
||||
(xy.y * lights.cluster_dimensions.x + xy.x) * lights.cluster_dimensions.z + z_slice,
|
||||
lights.cluster_dimensions.w - 1u
|
||||
);
|
||||
}
|
||||
|
||||
// this must match CLUSTER_COUNT_SIZE in light.rs
|
||||
let CLUSTER_COUNT_SIZE = 13u;
|
||||
fn unpack_offset_and_count(cluster_index: u32) -> vec2<u32> {
|
||||
#ifdef NO_STORAGE_BUFFERS_SUPPORT
|
||||
let offset_and_count = cluster_offsets_and_counts.data[cluster_index >> 2u][cluster_index & ((1u << 2u) - 1u)];
|
||||
return vec2<u32>(
|
||||
// The offset is stored in the upper 32 - CLUSTER_COUNT_SIZE = 19 bits
|
||||
(offset_and_count >> CLUSTER_COUNT_SIZE) & ((1u << 32u - CLUSTER_COUNT_SIZE) - 1u),
|
||||
// The count is stored in the lower CLUSTER_COUNT_SIZE = 13 bits
|
||||
offset_and_count & ((1u << CLUSTER_COUNT_SIZE) - 1u)
|
||||
);
|
||||
#else
|
||||
return cluster_offsets_and_counts.data[cluster_index];
|
||||
#endif
|
||||
}
|
||||
|
||||
fn get_light_id(index: u32) -> u32 {
|
||||
#ifdef NO_STORAGE_BUFFERS_SUPPORT
|
||||
// The index is correct but in cluster_light_index_lists we pack 4 u8s into a u32
|
||||
// This means the index into cluster_light_index_lists is index / 4
|
||||
let indices = cluster_light_index_lists.data[index >> 4u][(index >> 2u) & ((1u << 2u) - 1u)];
|
||||
// And index % 4 gives the sub-index of the u8 within the u32 so we shift by 8 * sub-index
|
||||
return (indices >> (8u * (index & ((1u << 2u) - 1u)))) & ((1u << 8u) - 1u);
|
||||
#else
|
||||
return cluster_light_index_lists.data[index];
|
||||
#endif
|
||||
}
|
||||
|
||||
fn point_light(
|
||||
world_position: vec3<f32>, light: PointLight, roughness: f32, NdotV: f32, N: vec3<f32>, V: vec3<f32>,
|
||||
R: vec3<f32>, F0: vec3<f32>, diffuseColor: vec3<f32>
|
||||
) -> vec3<f32> {
|
||||
let light_to_frag = light.position_radius.xyz - world_position.xyz;
|
||||
let distance_square = dot(light_to_frag, light_to_frag);
|
||||
let rangeAttenuation =
|
||||
getDistanceAttenuation(distance_square, light.color_inverse_square_range.w);
|
||||
|
||||
// Specular.
|
||||
// Representative Point Area Lights.
|
||||
// see http://blog.selfshadow.com/publications/s2013-shading-course/karis/s2013_pbs_epic_notes_v2.pdf p14-16
|
||||
let a = roughness;
|
||||
let centerToRay = dot(light_to_frag, R) * R - light_to_frag;
|
||||
let closestPoint = light_to_frag + centerToRay * saturate(light.position_radius.w * inverseSqrt(dot(centerToRay, centerToRay)));
|
||||
let LspecLengthInverse = inverseSqrt(dot(closestPoint, closestPoint));
|
||||
let normalizationFactor = a / saturate(a + (light.position_radius.w * 0.5 * LspecLengthInverse));
|
||||
let specularIntensity = normalizationFactor * normalizationFactor;
|
||||
|
||||
var L: vec3<f32> = closestPoint * LspecLengthInverse; // normalize() equivalent?
|
||||
var H: vec3<f32> = normalize(L + V);
|
||||
var NoL: f32 = saturate(dot(N, L));
|
||||
var NoH: f32 = saturate(dot(N, H));
|
||||
var LoH: f32 = saturate(dot(L, H));
|
||||
|
||||
let specular_light = specular(F0, roughness, H, NdotV, NoL, NoH, LoH, specularIntensity);
|
||||
|
||||
// Diffuse.
|
||||
// Comes after specular since its NoL is used in the lighting equation.
|
||||
L = normalize(light_to_frag);
|
||||
H = normalize(L + V);
|
||||
NoL = saturate(dot(N, L));
|
||||
NoH = saturate(dot(N, H));
|
||||
LoH = saturate(dot(L, H));
|
||||
|
||||
let diffuse = diffuseColor * Fd_Burley(roughness, NdotV, NoL, LoH);
|
||||
|
||||
// See https://google.github.io/filament/Filament.html#mjx-eqn-pointLightLuminanceEquation
|
||||
// Lout = f(v,l) Φ / { 4 π d^2 }⟨n⋅l⟩
|
||||
// where
|
||||
// f(v,l) = (f_d(v,l) + f_r(v,l)) * light_color
|
||||
// Φ is luminous power in lumens
|
||||
// our rangeAttentuation = 1 / d^2 multiplied with an attenuation factor for smoothing at the edge of the non-physical maximum light radius
|
||||
|
||||
// For a point light, luminous intensity, I, in lumens per steradian is given by:
|
||||
// I = Φ / 4 π
|
||||
// The derivation of this can be seen here: https://google.github.io/filament/Filament.html#mjx-eqn-pointLightLuminousPower
|
||||
|
||||
// NOTE: light.color.rgb is premultiplied with light.intensity / 4 π (which would be the luminous intensity) on the CPU
|
||||
|
||||
// TODO compensate for energy loss https://google.github.io/filament/Filament.html#materialsystem/improvingthebrdfs/energylossinspecularreflectance
|
||||
|
||||
return ((diffuse + specular_light) * light.color_inverse_square_range.rgb) * (rangeAttenuation * NoL);
|
||||
}
|
||||
|
||||
fn directional_light(light: DirectionalLight, roughness: f32, NdotV: f32, normal: vec3<f32>, view: vec3<f32>, R: vec3<f32>, F0: vec3<f32>, diffuseColor: vec3<f32>) -> vec3<f32> {
|
||||
let incident_light = light.direction_to_light.xyz;
|
||||
|
||||
let half_vector = normalize(incident_light + view);
|
||||
let NoL = saturate(dot(normal, incident_light));
|
||||
let NoH = saturate(dot(normal, half_vector));
|
||||
let LoH = saturate(dot(incident_light, half_vector));
|
||||
|
||||
let diffuse = diffuseColor * Fd_Burley(roughness, NdotV, NoL, LoH);
|
||||
let specularIntensity = 1.0;
|
||||
let specular_light = specular(F0, roughness, half_vector, NdotV, NoL, NoH, LoH, specularIntensity);
|
||||
|
||||
return (specular_light + diffuse) * light.color.rgb * NoL;
|
||||
}
|
||||
|
||||
fn fetch_point_shadow(light_id: u32, frag_position: vec4<f32>, surface_normal: vec3<f32>) -> f32 {
|
||||
let light = point_lights.data[light_id];
|
||||
|
||||
// because the shadow maps align with the axes and the frustum planes are at 45 degrees
|
||||
// we can get the worldspace depth by taking the largest absolute axis
|
||||
let surface_to_light = light.position_radius.xyz - frag_position.xyz;
|
||||
let surface_to_light_abs = abs(surface_to_light);
|
||||
let distance_to_light = max(surface_to_light_abs.x, max(surface_to_light_abs.y, surface_to_light_abs.z));
|
||||
|
||||
// The normal bias here is already scaled by the texel size at 1 world unit from the light.
|
||||
// The texel size increases proportionally with distance from the light so multiplying by
|
||||
// distance to light scales the normal bias to the texel size at the fragment distance.
|
||||
let normal_offset = light.shadow_normal_bias * distance_to_light * surface_normal.xyz;
|
||||
let depth_offset = light.shadow_depth_bias * normalize(surface_to_light.xyz);
|
||||
let offset_position = frag_position.xyz + normal_offset + depth_offset;
|
||||
|
||||
// similar largest-absolute-axis trick as above, but now with the offset fragment position
|
||||
let frag_ls = light.position_radius.xyz - offset_position.xyz;
|
||||
let abs_position_ls = abs(frag_ls);
|
||||
let major_axis_magnitude = max(abs_position_ls.x, max(abs_position_ls.y, abs_position_ls.z));
|
||||
|
||||
// NOTE: These simplifications come from multiplying:
|
||||
// projection * vec4(0, 0, -major_axis_magnitude, 1.0)
|
||||
// and keeping only the terms that have any impact on the depth.
|
||||
// Projection-agnostic approach:
|
||||
let zw = -major_axis_magnitude * light.projection_lr.xy + light.projection_lr.zw;
|
||||
let depth = zw.x / zw.y;
|
||||
|
||||
// do the lookup, using HW PCF and comparison
|
||||
// NOTE: Due to the non-uniform control flow above, we must use the Level variant of
|
||||
// textureSampleCompare to avoid undefined behaviour due to some of the fragments in
|
||||
// a quad (2x2 fragments) being processed not being sampled, and this messing with
|
||||
// mip-mapping functionality. The shadow maps have no mipmaps so Level just samples
|
||||
// from LOD 0.
|
||||
#ifdef NO_ARRAY_TEXTURES_SUPPORT
|
||||
return textureSampleCompare(point_shadow_textures, point_shadow_textures_sampler, frag_ls, depth);
|
||||
#else
|
||||
return textureSampleCompareLevel(point_shadow_textures, point_shadow_textures_sampler, frag_ls, i32(light_id), depth);
|
||||
#endif
|
||||
}
|
||||
|
||||
fn fetch_directional_shadow(light_id: u32, frag_position: vec4<f32>, surface_normal: vec3<f32>) -> f32 {
|
||||
let light = lights.directional_lights[light_id];
|
||||
|
||||
// The normal bias is scaled to the texel size.
|
||||
let normal_offset = light.shadow_normal_bias * surface_normal.xyz;
|
||||
let depth_offset = light.shadow_depth_bias * light.direction_to_light.xyz;
|
||||
let offset_position = vec4<f32>(frag_position.xyz + normal_offset + depth_offset, frag_position.w);
|
||||
|
||||
let offset_position_clip = light.view_projection * offset_position;
|
||||
if (offset_position_clip.w <= 0.0) {
|
||||
return 1.0;
|
||||
}
|
||||
let offset_position_ndc = offset_position_clip.xyz / offset_position_clip.w;
|
||||
// No shadow outside the orthographic projection volume
|
||||
if (any(offset_position_ndc.xy < vec2<f32>(-1.0)) || offset_position_ndc.z < 0.0
|
||||
|| any(offset_position_ndc > vec3<f32>(1.0))) {
|
||||
return 1.0;
|
||||
}
|
||||
|
||||
// compute texture coordinates for shadow lookup, compensating for the Y-flip difference
|
||||
// between the NDC and texture coordinates
|
||||
let flip_correction = vec2<f32>(0.5, -0.5);
|
||||
let light_local = offset_position_ndc.xy * flip_correction + vec2<f32>(0.5, 0.5);
|
||||
|
||||
let depth = offset_position_ndc.z;
|
||||
// do the lookup, using HW PCF and comparison
|
||||
// NOTE: Due to non-uniform control flow above, we must use the level variant of the texture
|
||||
// sampler to avoid use of implicit derivatives causing possible undefined behavior.
|
||||
#ifdef NO_ARRAY_TEXTURES_SUPPORT
|
||||
return textureSampleCompareLevel(directional_shadow_textures, directional_shadow_textures_sampler, light_local, depth);
|
||||
#else
|
||||
return textureSampleCompareLevel(directional_shadow_textures, directional_shadow_textures_sampler, light_local, i32(light_id), depth);
|
||||
#endif
|
||||
}
|
||||
|
||||
fn hsv2rgb(hue: f32, saturation: f32, value: f32) -> vec3<f32> {
|
||||
let rgb = clamp(
|
||||
abs(
|
||||
((hue * 6.0 + vec3<f32>(0.0, 4.0, 2.0)) % 6.0) - 3.0
|
||||
) - 1.0,
|
||||
vec3<f32>(0.0),
|
||||
vec3<f32>(1.0)
|
||||
);
|
||||
|
||||
return value * mix( vec3<f32>(1.0), rgb, vec3<f32>(saturation));
|
||||
}
|
||||
|
||||
fn random1D(s: f32) -> f32 {
|
||||
return fract(sin(s * 12.9898) * 43758.5453123);
|
||||
}
|
||||
#import bevy_pbr::utils
|
||||
#import bevy_pbr::clustered_forward
|
||||
#import bevy_pbr::lighting
|
||||
#import bevy_pbr::shadows
|
||||
|
||||
struct FragmentInput {
|
||||
[[builtin(front_facing)]] is_front: bool;
|
||||
|
|
@ -588,40 +187,13 @@ fn fragment(in: FragmentInput) -> [[location(0)]] vec4<f32> {
|
|||
emissive.rgb * output_color.a,
|
||||
output_color.a);
|
||||
|
||||
// Cluster allocation debug (using 'over' alpha blending)
|
||||
#ifdef CLUSTERED_FORWARD_DEBUG_Z_SLICES
|
||||
// NOTE: This debug mode visualises the z-slices
|
||||
let cluster_overlay_alpha = 0.1;
|
||||
var z_slice: u32 = view_z_to_z_slice(view_z, is_orthographic);
|
||||
// A hack to make the colors alternate a bit more
|
||||
if ((z_slice & 1u) == 1u) {
|
||||
z_slice = z_slice + lights.cluster_dimensions.z / 2u;
|
||||
}
|
||||
let slice_color = hsv2rgb(f32(z_slice) / f32(lights.cluster_dimensions.z + 1u), 1.0, 0.5);
|
||||
output_color = vec4<f32>(
|
||||
(1.0 - cluster_overlay_alpha) * output_color.rgb + cluster_overlay_alpha * slice_color,
|
||||
output_color.a
|
||||
output_color = cluster_debug_visualization(
|
||||
output_color,
|
||||
view_z,
|
||||
is_orthographic,
|
||||
offset_and_count,
|
||||
cluster_index,
|
||||
);
|
||||
#endif // CLUSTERED_FORWARD_DEBUG_Z_SLICES
|
||||
#ifdef CLUSTERED_FORWARD_DEBUG_CLUSTER_LIGHT_COMPLEXITY
|
||||
// NOTE: This debug mode visualises the number of lights within the cluster that contains
|
||||
// the fragment. It shows a sort of lighting complexity measure.
|
||||
let cluster_overlay_alpha = 0.1;
|
||||
let max_light_complexity_per_cluster = 64.0;
|
||||
output_color.r = (1.0 - cluster_overlay_alpha) * output_color.r
|
||||
+ cluster_overlay_alpha * smoothStep(0.0, max_light_complexity_per_cluster, f32(offset_and_count[1]));
|
||||
output_color.g = (1.0 - cluster_overlay_alpha) * output_color.g
|
||||
+ cluster_overlay_alpha * (1.0 - smoothStep(0.0, max_light_complexity_per_cluster, f32(offset_and_count[1])));
|
||||
#endif // CLUSTERED_FORWARD_DEBUG_CLUSTER_LIGHT_COMPLEXITY
|
||||
#ifdef CLUSTERED_FORWARD_DEBUG_CLUSTER_COHERENCY
|
||||
// NOTE: Visualizes the cluster to which the fragment belongs
|
||||
let cluster_overlay_alpha = 0.1;
|
||||
let cluster_color = hsv2rgb(random1D(f32(cluster_index)), 1.0, 0.5);
|
||||
output_color = vec4<f32>(
|
||||
(1.0 - cluster_overlay_alpha) * output_color.rgb + cluster_overlay_alpha * cluster_color,
|
||||
output_color.a
|
||||
);
|
||||
#endif // CLUSTERED_FORWARD_DEBUG_CLUSTER_COHERENCY
|
||||
|
||||
// tone_mapping
|
||||
output_color = vec4<f32>(reinhard_luminance(output_color.rgb), output_color.a);
|
||||
|
|
|
|||
255
crates/bevy_pbr/src/render/pbr_lighting.wgsl
Normal file
255
crates/bevy_pbr/src/render/pbr_lighting.wgsl
Normal file
|
|
@ -0,0 +1,255 @@
|
|||
#define_import_path bevy_pbr::lighting
|
||||
|
||||
// From the Filament design doc
|
||||
// https://google.github.io/filament/Filament.html#table_symbols
|
||||
// Symbol Definition
|
||||
// v View unit vector
|
||||
// l Incident light unit vector
|
||||
// n Surface normal unit vector
|
||||
// h Half unit vector between l and v
|
||||
// f BRDF
|
||||
// f_d Diffuse component of a BRDF
|
||||
// f_r Specular component of a BRDF
|
||||
// α Roughness, remapped from using input perceptualRoughness
|
||||
// σ Diffuse reflectance
|
||||
// Ω Spherical domain
|
||||
// f0 Reflectance at normal incidence
|
||||
// f90 Reflectance at grazing angle
|
||||
// χ+(a) Heaviside function (1 if a>0 and 0 otherwise)
|
||||
// nior Index of refraction (IOR) of an interface
|
||||
// ⟨n⋅l⟩ Dot product clamped to [0..1]
|
||||
// ⟨a⟩ Saturated value (clamped to [0..1])
|
||||
|
||||
// The Bidirectional Reflectance Distribution Function (BRDF) describes the surface response of a standard material
|
||||
// and consists of two components, the diffuse component (f_d) and the specular component (f_r):
|
||||
// f(v,l) = f_d(v,l) + f_r(v,l)
|
||||
//
|
||||
// The form of the microfacet model is the same for diffuse and specular
|
||||
// f_r(v,l) = f_d(v,l) = 1 / { |n⋅v||n⋅l| } ∫_Ω D(m,α) G(v,l,m) f_m(v,l,m) (v⋅m) (l⋅m) dm
|
||||
//
|
||||
// In which:
|
||||
// D, also called the Normal Distribution Function (NDF) models the distribution of the microfacets
|
||||
// G models the visibility (or occlusion or shadow-masking) of the microfacets
|
||||
// f_m is the microfacet BRDF and differs between specular and diffuse components
|
||||
//
|
||||
// The above integration needs to be approximated.
|
||||
|
||||
// distanceAttenuation is simply the square falloff of light intensity
|
||||
// combined with a smooth attenuation at the edge of the light radius
|
||||
//
|
||||
// light radius is a non-physical construct for efficiency purposes,
|
||||
// because otherwise every light affects every fragment in the scene
|
||||
fn getDistanceAttenuation(distanceSquare: f32, inverseRangeSquared: f32) -> f32 {
|
||||
let factor = distanceSquare * inverseRangeSquared;
|
||||
let smoothFactor = saturate(1.0 - factor * factor);
|
||||
let attenuation = smoothFactor * smoothFactor;
|
||||
return attenuation * 1.0 / max(distanceSquare, 0.0001);
|
||||
}
|
||||
|
||||
// Normal distribution function (specular D)
|
||||
// Based on https://google.github.io/filament/Filament.html#citation-walter07
|
||||
|
||||
// D_GGX(h,α) = α^2 / { π ((n⋅h)^2 (α2−1) + 1)^2 }
|
||||
|
||||
// Simple implementation, has precision problems when using fp16 instead of fp32
|
||||
// see https://google.github.io/filament/Filament.html#listing_speculardfp16
|
||||
fn D_GGX(roughness: f32, NoH: f32, h: vec3<f32>) -> f32 {
|
||||
let oneMinusNoHSquared = 1.0 - NoH * NoH;
|
||||
let a = NoH * roughness;
|
||||
let k = roughness / (oneMinusNoHSquared + a * a);
|
||||
let d = k * k * (1.0 / PI);
|
||||
return d;
|
||||
}
|
||||
|
||||
// Visibility function (Specular G)
|
||||
// V(v,l,a) = G(v,l,α) / { 4 (n⋅v) (n⋅l) }
|
||||
// such that f_r becomes
|
||||
// f_r(v,l) = D(h,α) V(v,l,α) F(v,h,f0)
|
||||
// where
|
||||
// V(v,l,α) = 0.5 / { n⋅l sqrt((n⋅v)^2 (1−α2) + α2) + n⋅v sqrt((n⋅l)^2 (1−α2) + α2) }
|
||||
// Note the two sqrt's, that may be slow on mobile, see https://google.github.io/filament/Filament.html#listing_approximatedspecularv
|
||||
fn V_SmithGGXCorrelated(roughness: f32, NoV: f32, NoL: f32) -> f32 {
|
||||
let a2 = roughness * roughness;
|
||||
let lambdaV = NoL * sqrt((NoV - a2 * NoV) * NoV + a2);
|
||||
let lambdaL = NoV * sqrt((NoL - a2 * NoL) * NoL + a2);
|
||||
let v = 0.5 / (lambdaV + lambdaL);
|
||||
return v;
|
||||
}
|
||||
|
||||
// Fresnel function
|
||||
// see https://google.github.io/filament/Filament.html#citation-schlick94
|
||||
// F_Schlick(v,h,f_0,f_90) = f_0 + (f_90 − f_0) (1 − v⋅h)^5
|
||||
fn F_Schlick_vec(f0: vec3<f32>, f90: f32, VoH: f32) -> vec3<f32> {
|
||||
// not using mix to keep the vec3 and float versions identical
|
||||
return f0 + (f90 - f0) * pow(1.0 - VoH, 5.0);
|
||||
}
|
||||
|
||||
fn F_Schlick(f0: f32, f90: f32, VoH: f32) -> f32 {
|
||||
// not using mix to keep the vec3 and float versions identical
|
||||
return f0 + (f90 - f0) * pow(1.0 - VoH, 5.0);
|
||||
}
|
||||
|
||||
fn fresnel(f0: vec3<f32>, LoH: f32) -> vec3<f32> {
|
||||
// f_90 suitable for ambient occlusion
|
||||
// see https://google.github.io/filament/Filament.html#lighting/occlusion
|
||||
let f90 = saturate(dot(f0, vec3<f32>(50.0 * 0.33)));
|
||||
return F_Schlick_vec(f0, f90, LoH);
|
||||
}
|
||||
|
||||
// Specular BRDF
|
||||
// https://google.github.io/filament/Filament.html#materialsystem/specularbrdf
|
||||
|
||||
// Cook-Torrance approximation of the microfacet model integration using Fresnel law F to model f_m
|
||||
// f_r(v,l) = { D(h,α) G(v,l,α) F(v,h,f0) } / { 4 (n⋅v) (n⋅l) }
|
||||
fn specular(f0: vec3<f32>, roughness: f32, h: vec3<f32>, NoV: f32, NoL: f32,
|
||||
NoH: f32, LoH: f32, specularIntensity: f32) -> vec3<f32> {
|
||||
let D = D_GGX(roughness, NoH, h);
|
||||
let V = V_SmithGGXCorrelated(roughness, NoV, NoL);
|
||||
let F = fresnel(f0, LoH);
|
||||
|
||||
return (specularIntensity * D * V) * F;
|
||||
}
|
||||
|
||||
// Diffuse BRDF
|
||||
// https://google.github.io/filament/Filament.html#materialsystem/diffusebrdf
|
||||
// fd(v,l) = σ/π * 1 / { |n⋅v||n⋅l| } ∫Ω D(m,α) G(v,l,m) (v⋅m) (l⋅m) dm
|
||||
//
|
||||
// simplest approximation
|
||||
// float Fd_Lambert() {
|
||||
// return 1.0 / PI;
|
||||
// }
|
||||
//
|
||||
// vec3 Fd = diffuseColor * Fd_Lambert();
|
||||
//
|
||||
// Disney approximation
|
||||
// See https://google.github.io/filament/Filament.html#citation-burley12
|
||||
// minimal quality difference
|
||||
fn Fd_Burley(roughness: f32, NoV: f32, NoL: f32, LoH: f32) -> f32 {
|
||||
let f90 = 0.5 + 2.0 * roughness * LoH * LoH;
|
||||
let lightScatter = F_Schlick(1.0, f90, NoL);
|
||||
let viewScatter = F_Schlick(1.0, f90, NoV);
|
||||
return lightScatter * viewScatter * (1.0 / PI);
|
||||
}
|
||||
|
||||
// From https://www.unrealengine.com/en-US/blog/physically-based-shading-on-mobile
|
||||
fn EnvBRDFApprox(f0: vec3<f32>, perceptual_roughness: f32, NoV: f32) -> vec3<f32> {
|
||||
let c0 = vec4<f32>(-1.0, -0.0275, -0.572, 0.022);
|
||||
let c1 = vec4<f32>(1.0, 0.0425, 1.04, -0.04);
|
||||
let r = perceptual_roughness * c0 + c1;
|
||||
let a004 = min(r.x * r.x, exp2(-9.28 * NoV)) * r.x + r.y;
|
||||
let AB = vec2<f32>(-1.04, 1.04) * a004 + r.zw;
|
||||
return f0 * AB.x + AB.y;
|
||||
}
|
||||
|
||||
fn perceptualRoughnessToRoughness(perceptualRoughness: f32) -> f32 {
|
||||
// clamp perceptual roughness to prevent precision problems
|
||||
// According to Filament design 0.089 is recommended for mobile
|
||||
// Filament uses 0.045 for non-mobile
|
||||
let clampedPerceptualRoughness = clamp(perceptualRoughness, 0.089, 1.0);
|
||||
return clampedPerceptualRoughness * clampedPerceptualRoughness;
|
||||
}
|
||||
|
||||
// from https://64.github.io/tonemapping/
|
||||
// reinhard on RGB oversaturates colors
|
||||
fn reinhard(color: vec3<f32>) -> vec3<f32> {
|
||||
return color / (1.0 + color);
|
||||
}
|
||||
|
||||
fn reinhard_extended(color: vec3<f32>, max_white: f32) -> vec3<f32> {
|
||||
let numerator = color * (1.0 + (color / vec3<f32>(max_white * max_white)));
|
||||
return numerator / (1.0 + color);
|
||||
}
|
||||
|
||||
// luminance coefficients from Rec. 709.
|
||||
// https://en.wikipedia.org/wiki/Rec._709
|
||||
fn luminance(v: vec3<f32>) -> f32 {
|
||||
return dot(v, vec3<f32>(0.2126, 0.7152, 0.0722));
|
||||
}
|
||||
|
||||
fn change_luminance(c_in: vec3<f32>, l_out: f32) -> vec3<f32> {
|
||||
let l_in = luminance(c_in);
|
||||
return c_in * (l_out / l_in);
|
||||
}
|
||||
|
||||
fn reinhard_luminance(color: vec3<f32>) -> vec3<f32> {
|
||||
let l_old = luminance(color);
|
||||
let l_new = l_old / (1.0 + l_old);
|
||||
return change_luminance(color, l_new);
|
||||
}
|
||||
|
||||
fn reinhard_extended_luminance(color: vec3<f32>, max_white_l: f32) -> vec3<f32> {
|
||||
let l_old = luminance(color);
|
||||
let numerator = l_old * (1.0 + (l_old / (max_white_l * max_white_l)));
|
||||
let l_new = numerator / (1.0 + l_old);
|
||||
return change_luminance(color, l_new);
|
||||
}
|
||||
|
||||
fn point_light(
|
||||
world_position: vec3<f32>, light: PointLight, roughness: f32, NdotV: f32, N: vec3<f32>, V: vec3<f32>,
|
||||
R: vec3<f32>, F0: vec3<f32>, diffuseColor: vec3<f32>
|
||||
) -> vec3<f32> {
|
||||
let light_to_frag = light.position_radius.xyz - world_position.xyz;
|
||||
let distance_square = dot(light_to_frag, light_to_frag);
|
||||
let rangeAttenuation =
|
||||
getDistanceAttenuation(distance_square, light.color_inverse_square_range.w);
|
||||
|
||||
// Specular.
|
||||
// Representative Point Area Lights.
|
||||
// see http://blog.selfshadow.com/publications/s2013-shading-course/karis/s2013_pbs_epic_notes_v2.pdf p14-16
|
||||
let a = roughness;
|
||||
let centerToRay = dot(light_to_frag, R) * R - light_to_frag;
|
||||
let closestPoint = light_to_frag + centerToRay * saturate(light.position_radius.w * inverseSqrt(dot(centerToRay, centerToRay)));
|
||||
let LspecLengthInverse = inverseSqrt(dot(closestPoint, closestPoint));
|
||||
let normalizationFactor = a / saturate(a + (light.position_radius.w * 0.5 * LspecLengthInverse));
|
||||
let specularIntensity = normalizationFactor * normalizationFactor;
|
||||
|
||||
var L: vec3<f32> = closestPoint * LspecLengthInverse; // normalize() equivalent?
|
||||
var H: vec3<f32> = normalize(L + V);
|
||||
var NoL: f32 = saturate(dot(N, L));
|
||||
var NoH: f32 = saturate(dot(N, H));
|
||||
var LoH: f32 = saturate(dot(L, H));
|
||||
|
||||
let specular_light = specular(F0, roughness, H, NdotV, NoL, NoH, LoH, specularIntensity);
|
||||
|
||||
// Diffuse.
|
||||
// Comes after specular since its NoL is used in the lighting equation.
|
||||
L = normalize(light_to_frag);
|
||||
H = normalize(L + V);
|
||||
NoL = saturate(dot(N, L));
|
||||
NoH = saturate(dot(N, H));
|
||||
LoH = saturate(dot(L, H));
|
||||
|
||||
let diffuse = diffuseColor * Fd_Burley(roughness, NdotV, NoL, LoH);
|
||||
|
||||
// See https://google.github.io/filament/Filament.html#mjx-eqn-pointLightLuminanceEquation
|
||||
// Lout = f(v,l) Φ / { 4 π d^2 }⟨n⋅l⟩
|
||||
// where
|
||||
// f(v,l) = (f_d(v,l) + f_r(v,l)) * light_color
|
||||
// Φ is luminous power in lumens
|
||||
// our rangeAttentuation = 1 / d^2 multiplied with an attenuation factor for smoothing at the edge of the non-physical maximum light radius
|
||||
|
||||
// For a point light, luminous intensity, I, in lumens per steradian is given by:
|
||||
// I = Φ / 4 π
|
||||
// The derivation of this can be seen here: https://google.github.io/filament/Filament.html#mjx-eqn-pointLightLuminousPower
|
||||
|
||||
// NOTE: light.color.rgb is premultiplied with light.intensity / 4 π (which would be the luminous intensity) on the CPU
|
||||
|
||||
// TODO compensate for energy loss https://google.github.io/filament/Filament.html#materialsystem/improvingthebrdfs/energylossinspecularreflectance
|
||||
|
||||
return ((diffuse + specular_light) * light.color_inverse_square_range.rgb) * (rangeAttenuation * NoL);
|
||||
}
|
||||
|
||||
fn directional_light(light: DirectionalLight, roughness: f32, NdotV: f32, normal: vec3<f32>, view: vec3<f32>, R: vec3<f32>, F0: vec3<f32>, diffuseColor: vec3<f32>) -> vec3<f32> {
|
||||
let incident_light = light.direction_to_light.xyz;
|
||||
|
||||
let half_vector = normalize(incident_light + view);
|
||||
let NoL = saturate(dot(normal, incident_light));
|
||||
let NoH = saturate(dot(normal, half_vector));
|
||||
let LoH = saturate(dot(incident_light, half_vector));
|
||||
|
||||
let diffuse = diffuseColor * Fd_Burley(roughness, NdotV, NoL, LoH);
|
||||
let specularIntensity = 1.0;
|
||||
let specular_light = specular(F0, roughness, half_vector, NdotV, NoL, NoH, LoH, specularIntensity);
|
||||
|
||||
return (specular_light + diffuse) * light.color.rgb * NoL;
|
||||
}
|
||||
77
crates/bevy_pbr/src/render/shadows.wgsl
Normal file
77
crates/bevy_pbr/src/render/shadows.wgsl
Normal file
|
|
@ -0,0 +1,77 @@
|
|||
#define_import_path bevy_pbr::shadows
|
||||
|
||||
fn fetch_point_shadow(light_id: u32, frag_position: vec4<f32>, surface_normal: vec3<f32>) -> f32 {
|
||||
let light = point_lights.data[light_id];
|
||||
|
||||
// because the shadow maps align with the axes and the frustum planes are at 45 degrees
|
||||
// we can get the worldspace depth by taking the largest absolute axis
|
||||
let surface_to_light = light.position_radius.xyz - frag_position.xyz;
|
||||
let surface_to_light_abs = abs(surface_to_light);
|
||||
let distance_to_light = max(surface_to_light_abs.x, max(surface_to_light_abs.y, surface_to_light_abs.z));
|
||||
|
||||
// The normal bias here is already scaled by the texel size at 1 world unit from the light.
|
||||
// The texel size increases proportionally with distance from the light so multiplying by
|
||||
// distance to light scales the normal bias to the texel size at the fragment distance.
|
||||
let normal_offset = light.shadow_normal_bias * distance_to_light * surface_normal.xyz;
|
||||
let depth_offset = light.shadow_depth_bias * normalize(surface_to_light.xyz);
|
||||
let offset_position = frag_position.xyz + normal_offset + depth_offset;
|
||||
|
||||
// similar largest-absolute-axis trick as above, but now with the offset fragment position
|
||||
let frag_ls = light.position_radius.xyz - offset_position.xyz;
|
||||
let abs_position_ls = abs(frag_ls);
|
||||
let major_axis_magnitude = max(abs_position_ls.x, max(abs_position_ls.y, abs_position_ls.z));
|
||||
|
||||
// NOTE: These simplifications come from multiplying:
|
||||
// projection * vec4(0, 0, -major_axis_magnitude, 1.0)
|
||||
// and keeping only the terms that have any impact on the depth.
|
||||
// Projection-agnostic approach:
|
||||
let zw = -major_axis_magnitude * light.projection_lr.xy + light.projection_lr.zw;
|
||||
let depth = zw.x / zw.y;
|
||||
|
||||
// do the lookup, using HW PCF and comparison
|
||||
// NOTE: Due to the non-uniform control flow above, we must use the Level variant of
|
||||
// textureSampleCompare to avoid undefined behaviour due to some of the fragments in
|
||||
// a quad (2x2 fragments) being processed not being sampled, and this messing with
|
||||
// mip-mapping functionality. The shadow maps have no mipmaps so Level just samples
|
||||
// from LOD 0.
|
||||
#ifdef NO_ARRAY_TEXTURES_SUPPORT
|
||||
return textureSampleCompare(point_shadow_textures, point_shadow_textures_sampler, frag_ls, depth);
|
||||
#else
|
||||
return textureSampleCompareLevel(point_shadow_textures, point_shadow_textures_sampler, frag_ls, i32(light_id), depth);
|
||||
#endif
|
||||
}
|
||||
|
||||
fn fetch_directional_shadow(light_id: u32, frag_position: vec4<f32>, surface_normal: vec3<f32>) -> f32 {
|
||||
let light = lights.directional_lights[light_id];
|
||||
|
||||
// The normal bias is scaled to the texel size.
|
||||
let normal_offset = light.shadow_normal_bias * surface_normal.xyz;
|
||||
let depth_offset = light.shadow_depth_bias * light.direction_to_light.xyz;
|
||||
let offset_position = vec4<f32>(frag_position.xyz + normal_offset + depth_offset, frag_position.w);
|
||||
|
||||
let offset_position_clip = light.view_projection * offset_position;
|
||||
if (offset_position_clip.w <= 0.0) {
|
||||
return 1.0;
|
||||
}
|
||||
let offset_position_ndc = offset_position_clip.xyz / offset_position_clip.w;
|
||||
// No shadow outside the orthographic projection volume
|
||||
if (any(offset_position_ndc.xy < vec2<f32>(-1.0)) || offset_position_ndc.z < 0.0
|
||||
|| any(offset_position_ndc > vec3<f32>(1.0))) {
|
||||
return 1.0;
|
||||
}
|
||||
|
||||
// compute texture coordinates for shadow lookup, compensating for the Y-flip difference
|
||||
// between the NDC and texture coordinates
|
||||
let flip_correction = vec2<f32>(0.5, -0.5);
|
||||
let light_local = offset_position_ndc.xy * flip_correction + vec2<f32>(0.5, 0.5);
|
||||
|
||||
let depth = offset_position_ndc.z;
|
||||
// do the lookup, using HW PCF and comparison
|
||||
// NOTE: Due to non-uniform control flow above, we must use the level variant of the texture
|
||||
// sampler to avoid use of implicit derivatives causing possible undefined behavior.
|
||||
#ifdef NO_ARRAY_TEXTURES_SUPPORT
|
||||
return textureSampleCompareLevel(directional_shadow_textures, directional_shadow_textures_sampler, light_local, depth);
|
||||
#else
|
||||
return textureSampleCompareLevel(directional_shadow_textures, directional_shadow_textures_sampler, light_local, i32(light_id), depth);
|
||||
#endif
|
||||
}
|
||||
23
crates/bevy_pbr/src/render/utils.wgsl
Normal file
23
crates/bevy_pbr/src/render/utils.wgsl
Normal file
|
|
@ -0,0 +1,23 @@
|
|||
#define_import_path bevy_pbr::utils
|
||||
|
||||
let PI: f32 = 3.141592653589793;
|
||||
|
||||
fn saturate(value: f32) -> f32 {
|
||||
return clamp(value, 0.0, 1.0);
|
||||
}
|
||||
|
||||
fn hsv2rgb(hue: f32, saturation: f32, value: f32) -> vec3<f32> {
|
||||
let rgb = clamp(
|
||||
abs(
|
||||
((hue * 6.0 + vec3<f32>(0.0, 4.0, 2.0)) % 6.0) - 3.0
|
||||
) - 1.0,
|
||||
vec3<f32>(0.0),
|
||||
vec3<f32>(1.0)
|
||||
);
|
||||
|
||||
return value * mix( vec3<f32>(1.0), rgb, vec3<f32>(saturation));
|
||||
}
|
||||
|
||||
fn random1D(s: f32) -> f32 {
|
||||
return fract(sin(s * 12.9898) * 43758.5453123);
|
||||
}
|
||||
Loading…
Reference in a new issue