Path: blob/main/crates/bevy_pbr/src/render/pbr_functions.wgsl
6600 views
#define_import_path bevy_pbr::pbr_functions
#import bevy_pbr::{
pbr_types,
pbr_bindings,
mesh_view_bindings as view_bindings,
mesh_view_types,
lighting,
lighting::{LAYER_BASE, LAYER_CLEARCOAT},
transmission,
clustered_forward as clustering,
shadows,
ambient,
irradiance_volume,
mesh_types::{MESH_FLAGS_SHADOW_RECEIVER_BIT, MESH_FLAGS_TRANSMITTED_SHADOW_RECEIVER_BIT},
}
#import bevy_render::maths::{E, powsafe}
#ifdef MESHLET_MESH_MATERIAL_PASS
#import bevy_pbr::meshlet_visibility_buffer_resolve::VertexOutput
#else ifdef PREPASS_PIPELINE
#import bevy_pbr::prepass_io::VertexOutput
#else // PREPASS_PIPELINE
#import bevy_pbr::forward_io::VertexOutput
#endif // PREPASS_PIPELINE
#ifdef ENVIRONMENT_MAP
#import bevy_pbr::environment_map
#endif
#ifdef TONEMAP_IN_SHADER
#import bevy_core_pipeline::tonemapping::{tone_mapping, screen_space_dither}
#endif
// Biasing info needed to sample from a texture. How this is done depends on
// whether we're rendering meshlets or regular meshes.
struct SampleBias {
#ifdef MESHLET_MESH_MATERIAL_PASS
ddx_uv: vec2<f32>,
ddy_uv: vec2<f32>,
#else // MESHLET_MESH_MATERIAL_PASS
mip_bias: f32,
#endif // MESHLET_MESH_MATERIAL_PASS
}
// This is the standard 4x4 ordered dithering pattern from [1].
//
// We can't use `array<vec4<u32>, 4>` because they can't be indexed dynamically
// due to Naga limitations. So instead we pack into a single `vec4` and extract
// individual bytes.
//
// [1]: https://en.wikipedia.org/wiki/Ordered_dithering#Threshold_map
const DITHER_THRESHOLD_MAP: vec4<u32> = vec4(
0x0a020800,
0x060e040c,
0x09010b03,
0x050d070f
);
// Processes a visibility range dither value and discards the fragment if
// needed.
//
// Visibility ranges, also known as HLODs, are crossfades between different
// levels of detail.
//
// The `dither` value ranges from [-16, 16]. When zooming out, positive values
// are used for meshes that are in the process of disappearing, while negative
// values are used for meshes that are in the process of appearing. In other
// words, when the camera is moving backwards, the `dither` value counts up from
// -16 to 0 when the object is fading in, stays at 0 while the object is
// visible, and then counts up to 16 while the object is fading out.
// Distinguishing between negative and positive values allows the dither
// patterns for different LOD levels of a single mesh to mesh together properly.
#ifdef VISIBILITY_RANGE_DITHER
fn visibility_range_dither(frag_coord: vec4<f32>, dither: i32) {
// If `dither` is 0, the object is visible.
if (dither == 0) {
return;
}
// If `dither` is less than -15 or greater than 15, the object is culled.
if (dither <= -16 || dither >= 16) {
discard;
}
// Otherwise, check the dither pattern.
let coords = vec2<u32>(floor(frag_coord.xy)) % 4u;
let threshold = i32((DITHER_THRESHOLD_MAP[coords.y] >> (coords.x * 8)) & 0xff);
if ((dither >= 0 && dither + threshold >= 16) || (dither < 0 && 1 + dither + threshold <= 0)) {
discard;
}
}
#endif
fn alpha_discard(material: pbr_types::StandardMaterial, output_color: vec4<f32>) -> vec4<f32> {
var color = output_color;
let alpha_mode = material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_RESERVED_BITS;
if alpha_mode == pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_OPAQUE {
// NOTE: If rendering as opaque, alpha should be ignored so set to 1.0
color.a = 1.0;
}
#ifdef MAY_DISCARD
// NOTE: `MAY_DISCARD` is only defined in the alpha to coverage case if MSAA
// was off. This special situation causes alpha to coverage to fall back to
// alpha mask.
else if alpha_mode == pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_MASK ||
alpha_mode == pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_ALPHA_TO_COVERAGE {
if color.a >= material.alpha_cutoff {
// NOTE: If rendering as masked alpha and >= the cutoff, render as fully opaque
color.a = 1.0;
} else {
// NOTE: output_color.a < in.material.alpha_cutoff should not be rendered
discard;
}
}
#endif
return color;
}
fn prepare_world_normal(
world_normal: vec3<f32>,
double_sided: bool,
is_front: bool,
) -> vec3<f32> {
var output: vec3<f32> = world_normal;
#ifndef VERTEX_TANGENTS
#ifndef STANDARD_MATERIAL_NORMAL_MAP
// NOTE: When NOT using normal-mapping, if looking at the back face of a double-sided
// material, the normal needs to be inverted. This is a branchless version of that.
output = (f32(!double_sided || is_front) * 2.0 - 1.0) * output;
#endif
#endif
return output;
}
// Calculates the three TBN vectors according to [mikktspace]. Returns a matrix
// with T, B, N columns in that order.
//
// [mikktspace]: http://www.mikktspace.com/
fn calculate_tbn_mikktspace(world_normal: vec3<f32>, world_tangent: vec4<f32>) -> mat3x3<f32> {
// NOTE: The mikktspace method of normal mapping explicitly requires that the world normal NOT
// be re-normalized in the fragment shader. This is primarily to match the way mikktspace
// bakes vertex tangents and normal maps so that this is the exact inverse. Blender, Unity,
// Unreal Engine, Godot, and more all use the mikktspace method. Do not change this code
// unless you really know what you are doing.
// http://www.mikktspace.com/
var N: vec3<f32> = world_normal;
// NOTE: The mikktspace method of normal mapping explicitly requires that these NOT be
// normalized nor any Gram-Schmidt applied to ensure the vertex normal is orthogonal to the
// vertex tangent! Do not change this code unless you really know what you are doing.
// http://www.mikktspace.com/
var T: vec3<f32> = world_tangent.xyz;
var B: vec3<f32> = world_tangent.w * cross(N, T);
#ifdef MESHLET_MESH_MATERIAL_PASS
// https://www.jeremyong.com/graphics/2023/12/16/surface-gradient-bump-mapping/#a-note-on-mikktspace-usage
let inverse_length_n = 1.0 / length(N);
T *= inverse_length_n;
B *= inverse_length_n;
N *= inverse_length_n;
#endif
return mat3x3(T, B, N);
}
fn apply_normal_mapping(
standard_material_flags: u32,
TBN: mat3x3<f32>,
double_sided: bool,
is_front: bool,
in_Nt: vec3<f32>,
) -> vec3<f32> {
// Unpack the TBN vectors.
var T = TBN[0];
var B = TBN[1];
var N = TBN[2];
// Nt is the tangent-space normal.
var Nt = in_Nt;
if (standard_material_flags & pbr_types::STANDARD_MATERIAL_FLAGS_TWO_COMPONENT_NORMAL_MAP) != 0u {
// Only use the xy components and derive z for 2-component normal maps.
Nt = vec3<f32>(Nt.rg * 2.0 - 1.0, 0.0);
Nt.z = sqrt(1.0 - Nt.x * Nt.x - Nt.y * Nt.y);
} else {
Nt = Nt * 2.0 - 1.0;
}
// Normal maps authored for DirectX require flipping the y component
if (standard_material_flags & pbr_types::STANDARD_MATERIAL_FLAGS_FLIP_NORMAL_MAP_Y) != 0u {
Nt.y = -Nt.y;
}
if double_sided && !is_front {
Nt = -Nt;
}
// NOTE: The mikktspace method of normal mapping applies maps the tangent-space normal from
// the normal map texture in this way to be an EXACT inverse of how the normal map baker
// calculates the normal maps so there is no error introduced. Do not change this code
// unless you really know what you are doing.
// http://www.mikktspace.com/
N = Nt.x * T + Nt.y * B + Nt.z * N;
return normalize(N);
}
#ifdef STANDARD_MATERIAL_ANISOTROPY
// Modifies the normal to achieve a better approximate direction from the
// environment map when using anisotropy.
//
// This follows the suggested implementation in the `KHR_materials_anisotropy` specification:
// https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Khronos/KHR_materials_anisotropy/README.md#image-based-lighting
fn bend_normal_for_anisotropy(lighting_input: ptr<function, lighting::LightingInput>) {
// Unpack.
let N = (*lighting_input).layers[LAYER_BASE].N;
let roughness = (*lighting_input).layers[LAYER_BASE].roughness;
let V = (*lighting_input).V;
let anisotropy = (*lighting_input).anisotropy;
let Ba = (*lighting_input).Ba;
var bent_normal = normalize(cross(cross(Ba, V), Ba));
// The `KHR_materials_anisotropy` spec states:
//
// > This heuristic can probably be improved upon
let a = pow(2.0, pow(2.0, 1.0 - anisotropy * (1.0 - roughness)));
bent_normal = normalize(mix(bent_normal, N, a));
// The `KHR_materials_anisotropy` spec states:
//
// > Mixing the reflection with the normal is more accurate both with and
// > without anisotropy and keeps rough objects from gathering light from
// > behind their tangent plane.
let R = normalize(mix(reflect(-V, bent_normal), bent_normal, roughness * roughness));
(*lighting_input).layers[LAYER_BASE].N = bent_normal;
(*lighting_input).layers[LAYER_BASE].R = R;
}
#endif // STANDARD_MATERIAL_ANISOTROPY
// NOTE: Correctly calculates the view vector depending on whether
// the projection is orthographic or perspective.
fn calculate_view(
world_position: vec4<f32>,
is_orthographic: bool,
) -> vec3<f32> {
var V: vec3<f32>;
if is_orthographic {
// Orthographic view vector
V = normalize(vec3<f32>(view_bindings::view.clip_from_world[0].z, view_bindings::view.clip_from_world[1].z, view_bindings::view.clip_from_world[2].z));
} else {
// Only valid for a perspective projection
V = normalize(view_bindings::view.world_position.xyz - world_position.xyz);
}
return V;
}
// Diffuse strength is inversely related to metallicity, specular and diffuse transmission
fn calculate_diffuse_color(
base_color: vec3<f32>,
metallic: f32,
specular_transmission: f32,
diffuse_transmission: f32
) -> vec3<f32> {
return base_color * (1.0 - metallic) * (1.0 - specular_transmission) *
(1.0 - diffuse_transmission);
}
// Remapping [0,1] reflectance to F0
// See https://google.github.io/filament/Filament.html#materialsystem/parameterization/remapping
fn calculate_F0(base_color: vec3<f32>, metallic: f32, reflectance: vec3<f32>) -> vec3<f32> {
return 0.16 * reflectance * reflectance * (1.0 - metallic) + base_color * metallic;
}
#ifndef PREPASS_FRAGMENT
fn apply_pbr_lighting(
in: pbr_types::PbrInput,
) -> vec4<f32> {
var output_color: vec4<f32> = in.material.base_color;
let emissive = in.material.emissive;
// calculate non-linear roughness from linear perceptualRoughness
let metallic = in.material.metallic;
let perceptual_roughness = in.material.perceptual_roughness;
let roughness = lighting::perceptualRoughnessToRoughness(perceptual_roughness);
let ior = in.material.ior;
let thickness = in.material.thickness;
let reflectance = in.material.reflectance;
let diffuse_transmission = in.material.diffuse_transmission;
let specular_transmission = in.material.specular_transmission;
let specular_transmissive_color = specular_transmission * in.material.base_color.rgb;
let diffuse_occlusion = in.diffuse_occlusion;
let specular_occlusion = in.specular_occlusion;
// Neubelt and Pettineo 2013, "Crafting a Next-gen Material Pipeline for The Order: 1886"
let NdotV = max(dot(in.N, in.V), 0.0001);
let R = reflect(-in.V, in.N);
#ifdef STANDARD_MATERIAL_CLEARCOAT
// Do the above calculations again for the clearcoat layer. Remember that
// the clearcoat can have its own roughness and its own normal.
let clearcoat = in.material.clearcoat;
let clearcoat_perceptual_roughness = in.material.clearcoat_perceptual_roughness;
let clearcoat_roughness = lighting::perceptualRoughnessToRoughness(clearcoat_perceptual_roughness);
let clearcoat_N = in.clearcoat_N;
let clearcoat_NdotV = max(dot(clearcoat_N, in.V), 0.0001);
let clearcoat_R = reflect(-in.V, clearcoat_N);
#endif // STANDARD_MATERIAL_CLEARCOAT
let diffuse_color = calculate_diffuse_color(
output_color.rgb,
metallic,
specular_transmission,
diffuse_transmission
);
// Diffuse transmissive strength is inversely related to metallicity and specular transmission, but directly related to diffuse transmission
let diffuse_transmissive_color = output_color.rgb * (1.0 - metallic) * (1.0 - specular_transmission) * diffuse_transmission;
// Calculate the world position of the second Lambertian lobe used for diffuse transmission, by subtracting material thickness
let diffuse_transmissive_lobe_world_position = in.world_position - vec4<f32>(in.world_normal, 0.0) * thickness;
let F0 = calculate_F0(output_color.rgb, metallic, reflectance);
let F_ab = lighting::F_AB(perceptual_roughness, NdotV);
var direct_light: vec3<f32> = vec3<f32>(0.0);
// Transmitted Light (Specular and Diffuse)
var transmitted_light: vec3<f32> = vec3<f32>(0.0);
// Pack all the values into a structure.
var lighting_input: lighting::LightingInput;
lighting_input.layers[LAYER_BASE].NdotV = NdotV;
lighting_input.layers[LAYER_BASE].N = in.N;
lighting_input.layers[LAYER_BASE].R = R;
lighting_input.layers[LAYER_BASE].perceptual_roughness = perceptual_roughness;
lighting_input.layers[LAYER_BASE].roughness = roughness;
lighting_input.P = in.world_position.xyz;
lighting_input.V = in.V;
lighting_input.diffuse_color = diffuse_color;
lighting_input.F0_ = F0;
lighting_input.F_ab = F_ab;
#ifdef STANDARD_MATERIAL_CLEARCOAT
lighting_input.layers[LAYER_CLEARCOAT].NdotV = clearcoat_NdotV;
lighting_input.layers[LAYER_CLEARCOAT].N = clearcoat_N;
lighting_input.layers[LAYER_CLEARCOAT].R = clearcoat_R;
lighting_input.layers[LAYER_CLEARCOAT].perceptual_roughness = clearcoat_perceptual_roughness;
lighting_input.layers[LAYER_CLEARCOAT].roughness = clearcoat_roughness;
lighting_input.clearcoat_strength = clearcoat;
#endif // STANDARD_MATERIAL_CLEARCOAT
#ifdef STANDARD_MATERIAL_ANISOTROPY
lighting_input.anisotropy = in.anisotropy_strength;
lighting_input.Ta = in.anisotropy_T;
lighting_input.Ba = in.anisotropy_B;
#endif // STANDARD_MATERIAL_ANISOTROPY
// And do the same for transmissive if we need to.
#ifdef STANDARD_MATERIAL_DIFFUSE_TRANSMISSION
var transmissive_lighting_input: lighting::LightingInput;
transmissive_lighting_input.layers[LAYER_BASE].NdotV = 1.0;
transmissive_lighting_input.layers[LAYER_BASE].N = -in.N;
transmissive_lighting_input.layers[LAYER_BASE].R = vec3(0.0);
transmissive_lighting_input.layers[LAYER_BASE].perceptual_roughness = 1.0;
transmissive_lighting_input.layers[LAYER_BASE].roughness = 1.0;
transmissive_lighting_input.P = diffuse_transmissive_lobe_world_position.xyz;
transmissive_lighting_input.V = -in.V;
transmissive_lighting_input.diffuse_color = diffuse_transmissive_color;
transmissive_lighting_input.F0_ = vec3(0.0);
transmissive_lighting_input.F_ab = vec2(0.1);
#ifdef STANDARD_MATERIAL_CLEARCOAT
transmissive_lighting_input.layers[LAYER_CLEARCOAT].NdotV = 0.0;
transmissive_lighting_input.layers[LAYER_CLEARCOAT].N = vec3(0.0);
transmissive_lighting_input.layers[LAYER_CLEARCOAT].R = vec3(0.0);
transmissive_lighting_input.layers[LAYER_CLEARCOAT].perceptual_roughness = 0.0;
transmissive_lighting_input.layers[LAYER_CLEARCOAT].roughness = 0.0;
transmissive_lighting_input.clearcoat_strength = 0.0;
#endif // STANDARD_MATERIAL_CLEARCOAT
#ifdef STANDARD_MATERIAL_ANISOTROPY
transmissive_lighting_input.anisotropy = in.anisotropy_strength;
transmissive_lighting_input.Ta = in.anisotropy_T;
transmissive_lighting_input.Ba = in.anisotropy_B;
#endif // STANDARD_MATERIAL_ANISOTROPY
#endif // STANDARD_MATERIAL_DIFFUSE_TRANSMISSION
let view_z = dot(vec4<f32>(
view_bindings::view.view_from_world[0].z,
view_bindings::view.view_from_world[1].z,
view_bindings::view.view_from_world[2].z,
view_bindings::view.view_from_world[3].z
), in.world_position);
let cluster_index = clustering::fragment_cluster_index(in.frag_coord.xy, view_z, in.is_orthographic);
var clusterable_object_index_ranges =
clustering::unpack_clusterable_object_index_ranges(cluster_index);
// Point lights (direct)
for (var i: u32 = clusterable_object_index_ranges.first_point_light_index_offset;
i < clusterable_object_index_ranges.first_spot_light_index_offset;
i = i + 1u) {
let light_id = clustering::get_clusterable_object_id(i);
// If we're lightmapped, disable diffuse contribution from the light if
// requested, to avoid double-counting light.
#ifdef LIGHTMAP
let enable_diffuse =
(view_bindings::clusterable_objects.data[light_id].flags &
mesh_view_types::POINT_LIGHT_FLAGS_AFFECTS_LIGHTMAPPED_MESH_DIFFUSE_BIT) != 0u;
#else // LIGHTMAP
let enable_diffuse = true;
#endif // LIGHTMAP
var shadow: f32 = 1.0;
if ((in.flags & MESH_FLAGS_SHADOW_RECEIVER_BIT) != 0u
&& (view_bindings::clusterable_objects.data[light_id].flags & mesh_view_types::POINT_LIGHT_FLAGS_SHADOWS_ENABLED_BIT) != 0u) {
shadow = shadows::fetch_point_shadow(light_id, in.world_position, in.world_normal);
}
let light_contrib = lighting::point_light(light_id, &lighting_input, enable_diffuse, true);
direct_light += light_contrib * shadow;
#ifdef STANDARD_MATERIAL_DIFFUSE_TRANSMISSION
// NOTE: We use the diffuse transmissive color, the second Lambertian lobe's calculated
// world position, inverted normal and view vectors, and the following simplified
// values for a fully diffuse transmitted light contribution approximation:
//
// roughness = 1.0;
// NdotV = 1.0;
// R = vec3<f32>(0.0) // doesn't really matter
// F_ab = vec2<f32>(0.1)
// F0 = vec3<f32>(0.0)
var transmitted_shadow: f32 = 1.0;
if ((in.flags & (MESH_FLAGS_SHADOW_RECEIVER_BIT | MESH_FLAGS_TRANSMITTED_SHADOW_RECEIVER_BIT)) == (MESH_FLAGS_SHADOW_RECEIVER_BIT | MESH_FLAGS_TRANSMITTED_SHADOW_RECEIVER_BIT)
&& (view_bindings::clusterable_objects.data[light_id].flags & mesh_view_types::POINT_LIGHT_FLAGS_SHADOWS_ENABLED_BIT) != 0u) {
transmitted_shadow = shadows::fetch_point_shadow(light_id, diffuse_transmissive_lobe_world_position, -in.world_normal);
}
let transmitted_light_contrib =
lighting::point_light(light_id, &transmissive_lighting_input, enable_diffuse, true);
transmitted_light += transmitted_light_contrib * transmitted_shadow;
#endif
}
// Spot lights (direct)
for (var i: u32 = clusterable_object_index_ranges.first_spot_light_index_offset;
i < clusterable_object_index_ranges.first_reflection_probe_index_offset;
i = i + 1u) {
let light_id = clustering::get_clusterable_object_id(i);
// If we're lightmapped, disable diffuse contribution from the light if
// requested, to avoid double-counting light.
#ifdef LIGHTMAP
let enable_diffuse =
(view_bindings::clusterable_objects.data[light_id].flags &
mesh_view_types::POINT_LIGHT_FLAGS_AFFECTS_LIGHTMAPPED_MESH_DIFFUSE_BIT) != 0u;
#else // LIGHTMAP
let enable_diffuse = true;
#endif // LIGHTMAP
var shadow: f32 = 1.0;
if ((in.flags & MESH_FLAGS_SHADOW_RECEIVER_BIT) != 0u
&& (view_bindings::clusterable_objects.data[light_id].flags &
mesh_view_types::POINT_LIGHT_FLAGS_SHADOWS_ENABLED_BIT) != 0u) {
shadow = shadows::fetch_spot_shadow(
light_id,
in.world_position,
in.world_normal,
view_bindings::clusterable_objects.data[light_id].shadow_map_near_z,
);
}
let light_contrib = lighting::spot_light(light_id, &lighting_input, enable_diffuse);
direct_light += light_contrib * shadow;
#ifdef STANDARD_MATERIAL_DIFFUSE_TRANSMISSION
// NOTE: We use the diffuse transmissive color, the second Lambertian lobe's calculated
// world position, inverted normal and view vectors, and the following simplified
// values for a fully diffuse transmitted light contribution approximation:
//
// roughness = 1.0;
// NdotV = 1.0;
// R = vec3<f32>(0.0) // doesn't really matter
// F_ab = vec2<f32>(0.1)
// F0 = vec3<f32>(0.0)
var transmitted_shadow: f32 = 1.0;
if ((in.flags & (MESH_FLAGS_SHADOW_RECEIVER_BIT | MESH_FLAGS_TRANSMITTED_SHADOW_RECEIVER_BIT)) == (MESH_FLAGS_SHADOW_RECEIVER_BIT | MESH_FLAGS_TRANSMITTED_SHADOW_RECEIVER_BIT)
&& (view_bindings::clusterable_objects.data[light_id].flags & mesh_view_types::POINT_LIGHT_FLAGS_SHADOWS_ENABLED_BIT) != 0u) {
transmitted_shadow = shadows::fetch_spot_shadow(
light_id,
diffuse_transmissive_lobe_world_position,
-in.world_normal,
view_bindings::clusterable_objects.data[light_id].shadow_map_near_z,
);
}
let transmitted_light_contrib =
lighting::spot_light(light_id, &transmissive_lighting_input, enable_diffuse);
transmitted_light += transmitted_light_contrib * transmitted_shadow;
#endif
}
// directional lights (direct)
let n_directional_lights = view_bindings::lights.n_directional_lights;
for (var i: u32 = 0u; i < n_directional_lights; i = i + 1u) {
// check if this light should be skipped, which occurs if this light does not intersect with the view
// note point and spot lights aren't skippable, as the relevant lights are filtered in `assign_lights_to_clusters`
let light = &view_bindings::lights.directional_lights[i];
// If we're lightmapped, disable diffuse contribution from the light if
// requested, to avoid double-counting light.
#ifdef LIGHTMAP
let enable_diffuse =
((*light).flags &
mesh_view_types::DIRECTIONAL_LIGHT_FLAGS_AFFECTS_LIGHTMAPPED_MESH_DIFFUSE_BIT) !=
0u;
#else // LIGHTMAP
let enable_diffuse = true;
#endif // LIGHTMAP
var shadow: f32 = 1.0;
if ((in.flags & MESH_FLAGS_SHADOW_RECEIVER_BIT) != 0u
&& (view_bindings::lights.directional_lights[i].flags & mesh_view_types::DIRECTIONAL_LIGHT_FLAGS_SHADOWS_ENABLED_BIT) != 0u) {
shadow = shadows::fetch_directional_shadow(i, in.world_position, in.world_normal, view_z);
}
var light_contrib = lighting::directional_light(i, &lighting_input, enable_diffuse);
#ifdef DIRECTIONAL_LIGHT_SHADOW_MAP_DEBUG_CASCADES
light_contrib = shadows::cascade_debug_visualization(light_contrib, i, view_z);
#endif
direct_light += light_contrib * shadow;
#ifdef STANDARD_MATERIAL_DIFFUSE_TRANSMISSION
// NOTE: We use the diffuse transmissive color, the second Lambertian lobe's calculated
// world position, inverted normal and view vectors, and the following simplified
// values for a fully diffuse transmitted light contribution approximation:
//
// roughness = 1.0;
// NdotV = 1.0;
// R = vec3<f32>(0.0) // doesn't really matter
// F_ab = vec2<f32>(0.1)
// F0 = vec3<f32>(0.0)
var transmitted_shadow: f32 = 1.0;
if ((in.flags & (MESH_FLAGS_SHADOW_RECEIVER_BIT | MESH_FLAGS_TRANSMITTED_SHADOW_RECEIVER_BIT)) == (MESH_FLAGS_SHADOW_RECEIVER_BIT | MESH_FLAGS_TRANSMITTED_SHADOW_RECEIVER_BIT)
&& (view_bindings::lights.directional_lights[i].flags & mesh_view_types::DIRECTIONAL_LIGHT_FLAGS_SHADOWS_ENABLED_BIT) != 0u) {
transmitted_shadow = shadows::fetch_directional_shadow(i, diffuse_transmissive_lobe_world_position, -in.world_normal, view_z);
}
let transmitted_light_contrib =
lighting::directional_light(i, &transmissive_lighting_input, enable_diffuse);
transmitted_light += transmitted_light_contrib * transmitted_shadow;
#endif
}
#ifdef STANDARD_MATERIAL_DIFFUSE_TRANSMISSION
// NOTE: We use the diffuse transmissive color, the second Lambertian lobe's calculated
// world position, inverted normal and view vectors, and the following simplified
// values for a fully diffuse transmitted light contribution approximation:
//
// perceptual_roughness = 1.0;
// NdotV = 1.0;
// F0 = vec3<f32>(0.0)
// diffuse_occlusion = vec3<f32>(1.0)
transmitted_light += ambient::ambient_light(diffuse_transmissive_lobe_world_position, -in.N, -in.V, 1.0, diffuse_transmissive_color, vec3<f32>(0.0), 1.0, vec3<f32>(1.0));
#endif
// Diffuse indirect lighting can come from a variety of sources. The
// priority goes like this:
//
// 1. Lightmap (highest)
// 2. Irradiance volume
// 3. Environment map (lowest)
//
// When we find a source of diffuse indirect lighting, we stop accumulating
// any more diffuse indirect light. This avoids double-counting if, for
// example, both lightmaps and irradiance volumes are present.
var indirect_light = vec3(0.0f);
var found_diffuse_indirect = false;
#ifdef LIGHTMAP
indirect_light += in.lightmap_light * diffuse_color;
found_diffuse_indirect = true;
#endif
#ifdef IRRADIANCE_VOLUME
// Irradiance volume light (indirect)
if (!found_diffuse_indirect) {
let irradiance_volume_light = irradiance_volume::irradiance_volume_light(
in.world_position.xyz,
in.N,
&clusterable_object_index_ranges,
);
indirect_light += irradiance_volume_light * diffuse_color * diffuse_occlusion;
found_diffuse_indirect = true;
}
#endif
// Environment map light (indirect)
#ifdef ENVIRONMENT_MAP
// If screen space reflections are going to be used for this material, don't
// accumulate environment map light yet. The SSR shader will do it.
#ifdef SCREEN_SPACE_REFLECTIONS
let use_ssr = perceptual_roughness <=
view_bindings::ssr_settings.perceptual_roughness_threshold;
#else // SCREEN_SPACE_REFLECTIONS
let use_ssr = false;
#endif // SCREEN_SPACE_REFLECTIONS
if (!use_ssr) {
#ifdef STANDARD_MATERIAL_ANISOTROPY
var bent_normal_lighting_input = lighting_input;
bend_normal_for_anisotropy(&bent_normal_lighting_input);
let environment_map_lighting_input = &bent_normal_lighting_input;
#else // STANDARD_MATERIAL_ANISOTROPY
let environment_map_lighting_input = &lighting_input;
#endif // STANDARD_MATERIAL_ANISOTROPY
let environment_light = environment_map::environment_map_light(
environment_map_lighting_input,
&clusterable_object_index_ranges,
found_diffuse_indirect,
);
indirect_light += environment_light.diffuse * diffuse_occlusion +
environment_light.specular * specular_occlusion;
}
#endif // ENVIRONMENT_MAP
// Ambient light (indirect)
// If we are lightmapped, disable the ambient contribution if requested.
// This is to avoid double-counting ambient light. (It might be part of the lightmap)
#ifdef LIGHTMAP
let enable_ambient = view_bindings::lights.ambient_light_affects_lightmapped_meshes != 0u;
#else // LIGHTMAP
let enable_ambient = true;
#endif // LIGHTMAP
if (enable_ambient) {
indirect_light += ambient::ambient_light(in.world_position, in.N, in.V, NdotV, diffuse_color, F0, perceptual_roughness, diffuse_occlusion);
}
// we'll use the specular component of the transmitted environment
// light in the call to `specular_transmissive_light()` below
var specular_transmitted_environment_light = vec3<f32>(0.0);
#ifdef ENVIRONMENT_MAP
#ifdef STANDARD_MATERIAL_DIFFUSE_OR_SPECULAR_TRANSMISSION
// NOTE: We use the diffuse transmissive color, inverted normal and view vectors,
// and the following simplified values for the transmitted environment light contribution
// approximation:
//
// diffuse_color = vec3<f32>(1.0) // later we use `diffuse_transmissive_color` and `specular_transmissive_color`
// NdotV = 1.0;
// R = T // see definition below
// F0 = vec3<f32>(1.0)
// diffuse_occlusion = 1.0
//
// (This one is slightly different from the other light types above, because the environment
// map light returns both diffuse and specular components separately, and we want to use both)
let T = -normalize(
in.V + // start with view vector at entry point
refract(in.V, -in.N, 1.0 / ior) * thickness // add refracted vector scaled by thickness, towards exit point
); // normalize to find exit point view vector
var transmissive_environment_light_input: lighting::LightingInput;
transmissive_environment_light_input.diffuse_color = vec3(1.0);
transmissive_environment_light_input.layers[LAYER_BASE].NdotV = 1.0;
transmissive_environment_light_input.P = in.world_position.xyz;
transmissive_environment_light_input.layers[LAYER_BASE].N = -in.N;
transmissive_environment_light_input.V = in.V;
transmissive_environment_light_input.layers[LAYER_BASE].R = T;
transmissive_environment_light_input.layers[LAYER_BASE].perceptual_roughness = perceptual_roughness;
transmissive_environment_light_input.layers[LAYER_BASE].roughness = roughness;
transmissive_environment_light_input.F0_ = vec3<f32>(1.0);
transmissive_environment_light_input.F_ab = vec2(0.1);
#ifdef STANDARD_MATERIAL_CLEARCOAT
// No clearcoat.
transmissive_environment_light_input.clearcoat_strength = 0.0;
transmissive_environment_light_input.layers[LAYER_CLEARCOAT].NdotV = 0.0;
transmissive_environment_light_input.layers[LAYER_CLEARCOAT].N = in.N;
transmissive_environment_light_input.layers[LAYER_CLEARCOAT].R = vec3(0.0);
transmissive_environment_light_input.layers[LAYER_CLEARCOAT].perceptual_roughness = 0.0;
transmissive_environment_light_input.layers[LAYER_CLEARCOAT].roughness = 0.0;
#endif // STANDARD_MATERIAL_CLEARCOAT
let transmitted_environment_light = environment_map::environment_map_light(
&transmissive_environment_light_input,
&clusterable_object_index_ranges,
false,
);
#ifdef STANDARD_MATERIAL_DIFFUSE_TRANSMISSION
transmitted_light += transmitted_environment_light.diffuse * diffuse_transmissive_color;
#endif // STANDARD_MATERIAL_DIFFUSE_TRANSMISSION
#ifdef STANDARD_MATERIAL_SPECULAR_TRANSMISSION
specular_transmitted_environment_light = transmitted_environment_light.specular * specular_transmissive_color;
#endif // STANDARD_MATERIAL_SPECULAR_TRANSMISSION
#endif // STANDARD_MATERIAL_SPECULAR_OR_DIFFUSE_TRANSMISSION
#endif // ENVIRONMENT_MAP
var emissive_light = emissive.rgb * output_color.a;
// "The clearcoat layer is on top of emission in the layering stack.
// Consequently, the emission is darkened by the Fresnel term."
//
// <https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Khronos/KHR_materials_clearcoat/README.md#emission>
#ifdef STANDARD_MATERIAL_CLEARCOAT
emissive_light = emissive_light * (0.04 + (1.0 - 0.04) * pow(1.0 - clearcoat_NdotV, 5.0));
#endif
emissive_light = emissive_light * mix(1.0, view_bindings::view.exposure, emissive.a);
#ifdef STANDARD_MATERIAL_SPECULAR_TRANSMISSION
transmitted_light += transmission::specular_transmissive_light(in.world_position, in.frag_coord.xyz, view_z, in.N, in.V, F0, ior, thickness, perceptual_roughness, specular_transmissive_color, specular_transmitted_environment_light).rgb;
if (in.material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_ATTENUATION_ENABLED_BIT) != 0u {
// We reuse the `atmospheric_fog()` function here, as it's fundamentally
// equivalent to the attenuation that takes place inside the material volume,
// and will allow us to eventually hook up subsurface scattering more easily
var attenuation_fog: mesh_view_types::Fog;
attenuation_fog.base_color.a = 1.0;
attenuation_fog.be = pow(1.0 - in.material.attenuation_color.rgb, vec3<f32>(E)) / in.material.attenuation_distance;
// TODO: Add the subsurface scattering factor below
// attenuation_fog.bi = /* ... */
transmitted_light = bevy_pbr::fog::atmospheric_fog(
attenuation_fog, vec4<f32>(transmitted_light, 1.0), thickness,
vec3<f32>(0.0) // TODO: Pass in (pre-attenuated) scattered light contribution here
).rgb;
}
#endif
// Total light
output_color = vec4<f32>(
(view_bindings::view.exposure * (transmitted_light + direct_light + indirect_light)) + emissive_light,
output_color.a
);
output_color = clustering::cluster_debug_visualization(
output_color,
view_z,
in.is_orthographic,
clusterable_object_index_ranges,
cluster_index,
);
return output_color;
}
#endif // PREPASS_FRAGMENT
#ifdef DISTANCE_FOG
fn apply_fog(fog_params: mesh_view_types::Fog, input_color: vec4<f32>, fragment_world_position: vec3<f32>, view_world_position: vec3<f32>) -> vec4<f32> {
let view_to_world = fragment_world_position.xyz - view_world_position.xyz;
// `length()` is used here instead of just `view_to_world.z` since that produces more
// high quality results, especially for denser/smaller fogs. we get a "curved"
// fog shape that remains consistent with camera rotation, instead of a "linear"
// fog shape that looks a bit fake
let distance = length(view_to_world);
var scattering = vec3<f32>(0.0);
if fog_params.directional_light_color.a > 0.0 {
let view_to_world_normalized = view_to_world / distance;
let n_directional_lights = view_bindings::lights.n_directional_lights;
for (var i: u32 = 0u; i < n_directional_lights; i = i + 1u) {
let light = view_bindings::lights.directional_lights[i];
scattering += pow(
max(
dot(view_to_world_normalized, light.direction_to_light),
0.0
),
fog_params.directional_light_exponent
) * light.color.rgb * view_bindings::view.exposure;
}
}
if fog_params.mode == mesh_view_types::FOG_MODE_LINEAR {
return bevy_pbr::fog::linear_fog(fog_params, input_color, distance, scattering);
} else if fog_params.mode == mesh_view_types::FOG_MODE_EXPONENTIAL {
return bevy_pbr::fog::exponential_fog(fog_params, input_color, distance, scattering);
} else if fog_params.mode == mesh_view_types::FOG_MODE_EXPONENTIAL_SQUARED {
return bevy_pbr::fog::exponential_squared_fog(fog_params, input_color, distance, scattering);
} else if fog_params.mode == mesh_view_types::FOG_MODE_ATMOSPHERIC {
return bevy_pbr::fog::atmospheric_fog(fog_params, input_color, distance, scattering);
} else {
return input_color;
}
}
#endif // DISTANCE_FOG
#ifdef PREMULTIPLY_ALPHA
fn premultiply_alpha(standard_material_flags: u32, color: vec4<f32>) -> vec4<f32> {
// `Blend`, `Premultiplied` and `Alpha` all share the same `BlendState`. Depending
// on the alpha mode, we premultiply the color channels by the alpha channel value,
// (and also optionally replace the alpha value with 0.0) so that the result produces
// the desired blend mode when sent to the blending operation.
#ifdef BLEND_PREMULTIPLIED_ALPHA
// For `BlendState::PREMULTIPLIED_ALPHA_BLENDING` the blend function is:
//
// result = 1 * src_color + (1 - src_alpha) * dst_color
let alpha_mode = standard_material_flags & pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_RESERVED_BITS;
if alpha_mode == pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_ADD {
// Here, we premultiply `src_color` by `src_alpha`, and replace `src_alpha` with 0.0:
//
// src_color *= src_alpha
// src_alpha = 0.0
//
// We end up with:
//
// result = 1 * (src_alpha * src_color) + (1 - 0) * dst_color
// result = src_alpha * src_color + 1 * dst_color
//
// Which is the blend operation for additive blending
return vec4<f32>(color.rgb * color.a, 0.0);
} else {
// Here, we don't do anything, so that we get premultiplied alpha blending. (As expected)
return color.rgba;
}
#endif
// `Multiply` uses its own `BlendState`, but we still need to premultiply here in the
// shader so that we get correct results as we tweak the alpha channel
#ifdef BLEND_MULTIPLY
// The blend function is:
//
// result = dst_color * src_color + (1 - src_alpha) * dst_color
//
// We premultiply `src_color` by `src_alpha`:
//
// src_color *= src_alpha
//
// We end up with:
//
// result = dst_color * (src_color * src_alpha) + (1 - src_alpha) * dst_color
// result = src_alpha * (src_color * dst_color) + (1 - src_alpha) * dst_color
//
// Which is the blend operation for multiplicative blending with arbitrary mixing
// controlled by the source alpha channel
return vec4<f32>(color.rgb * color.a, color.a);
#endif
}
#endif
// fog, alpha premultiply
// for non-hdr cameras, tonemapping and debanding
fn main_pass_post_lighting_processing(
pbr_input: pbr_types::PbrInput,
input_color: vec4<f32>,
) -> vec4<f32> {
var output_color = input_color;
#ifdef DISTANCE_FOG
// fog
if ((pbr_input.material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_FOG_ENABLED_BIT) != 0u) {
output_color = apply_fog(view_bindings::fog, output_color, pbr_input.world_position.xyz, view_bindings::view.world_position.xyz);
}
#endif // DISTANCE_FOG
#ifdef TONEMAP_IN_SHADER
output_color = tone_mapping(output_color, view_bindings::view.color_grading);
#ifdef DEBAND_DITHER
var output_rgb = output_color.rgb;
output_rgb = powsafe(output_rgb, 1.0 / 2.2);
output_rgb += screen_space_dither(pbr_input.frag_coord.xy);
// This conversion back to linear space is required because our output texture format is
// SRGB; the GPU will assume our output is linear and will apply an SRGB conversion.
output_rgb = powsafe(output_rgb, 2.2);
output_color = vec4(output_rgb, output_color.a);
#endif
#endif
#ifdef PREMULTIPLY_ALPHA
output_color = premultiply_alpha(pbr_input.material.flags, output_color);
#endif
return output_color;
}