bevy/crates/bevy_pbr/src/render/pbr_fragment.wgsl

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#define_import_path bevy_pbr::pbr_fragment
update shader imports (#10180) # Objective - bump naga_oil to 0.10 - update shader imports to use rusty syntax ## Migration Guide naga_oil 0.10 reworks the import mechanism to support more syntax to make it more rusty, and test for item use before importing to determine which imports are modules and which are items, which allows: - use rust-style imports ``` #import bevy_pbr::{ pbr_functions::{alpha_discard as discard, apply_pbr_lighting}, mesh_bindings, } ``` - import partial paths: ``` #import part::of::path ... path::remainder::function(); ``` which will call to `part::of::path::remainder::function` - use fully qualified paths without importing: ``` // #import bevy_pbr::pbr_functions bevy_pbr::pbr_functions::pbr() ``` - use imported items without qualifying ``` #import bevy_pbr::pbr_functions::pbr // for backwards compatibility the old style is still supported: // #import bevy_pbr::pbr_functions pbr ... pbr() ``` - allows most imported items to end with `_` and numbers (naga_oil#30). still doesn't allow struct members to end with `_` or numbers but it's progress. - the vast majority of existing shader code will work without changes, but will emit "deprecated" warnings for old-style imports. these can be suppressed with the `allow-deprecated` feature. - partly breaks overrides (as far as i'm aware nobody uses these yet) - now overrides will only be applied if the overriding module is added as an additional import in the arguments to `Composer::make_naga_module` or `Composer::add_composable_module`. this is necessary to support determining whether imports are modules or items.
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#import bevy_pbr::{
pbr_functions,
pbr_bindings,
pbr_types,
prepass_utils,
mesh_bindings::mesh,
mesh_view_bindings::view,
parallax_mapping::parallaxed_uv,
lightmap::lightmap,
update shader imports (#10180) # Objective - bump naga_oil to 0.10 - update shader imports to use rusty syntax ## Migration Guide naga_oil 0.10 reworks the import mechanism to support more syntax to make it more rusty, and test for item use before importing to determine which imports are modules and which are items, which allows: - use rust-style imports ``` #import bevy_pbr::{ pbr_functions::{alpha_discard as discard, apply_pbr_lighting}, mesh_bindings, } ``` - import partial paths: ``` #import part::of::path ... path::remainder::function(); ``` which will call to `part::of::path::remainder::function` - use fully qualified paths without importing: ``` // #import bevy_pbr::pbr_functions bevy_pbr::pbr_functions::pbr() ``` - use imported items without qualifying ``` #import bevy_pbr::pbr_functions::pbr // for backwards compatibility the old style is still supported: // #import bevy_pbr::pbr_functions pbr ... pbr() ``` - allows most imported items to end with `_` and numbers (naga_oil#30). still doesn't allow struct members to end with `_` or numbers but it's progress. - the vast majority of existing shader code will work without changes, but will emit "deprecated" warnings for old-style imports. these can be suppressed with the `allow-deprecated` feature. - partly breaks overrides (as far as i'm aware nobody uses these yet) - now overrides will only be applied if the overriding module is added as an additional import in the arguments to `Composer::make_naga_module` or `Composer::add_composable_module`. this is necessary to support determining whether imports are modules or items.
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}
#ifdef SCREEN_SPACE_AMBIENT_OCCLUSION
update shader imports (#10180) # Objective - bump naga_oil to 0.10 - update shader imports to use rusty syntax ## Migration Guide naga_oil 0.10 reworks the import mechanism to support more syntax to make it more rusty, and test for item use before importing to determine which imports are modules and which are items, which allows: - use rust-style imports ``` #import bevy_pbr::{ pbr_functions::{alpha_discard as discard, apply_pbr_lighting}, mesh_bindings, } ``` - import partial paths: ``` #import part::of::path ... path::remainder::function(); ``` which will call to `part::of::path::remainder::function` - use fully qualified paths without importing: ``` // #import bevy_pbr::pbr_functions bevy_pbr::pbr_functions::pbr() ``` - use imported items without qualifying ``` #import bevy_pbr::pbr_functions::pbr // for backwards compatibility the old style is still supported: // #import bevy_pbr::pbr_functions pbr ... pbr() ``` - allows most imported items to end with `_` and numbers (naga_oil#30). still doesn't allow struct members to end with `_` or numbers but it's progress. - the vast majority of existing shader code will work without changes, but will emit "deprecated" warnings for old-style imports. these can be suppressed with the `allow-deprecated` feature. - partly breaks overrides (as far as i'm aware nobody uses these yet) - now overrides will only be applied if the overriding module is added as an additional import in the arguments to `Composer::make_naga_module` or `Composer::add_composable_module`. this is necessary to support determining whether imports are modules or items.
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#import bevy_pbr::mesh_view_bindings::screen_space_ambient_occlusion_texture
#import bevy_pbr::gtao_utils::gtao_multibounce
#endif
#ifdef PREPASS_PIPELINE
update shader imports (#10180) # Objective - bump naga_oil to 0.10 - update shader imports to use rusty syntax ## Migration Guide naga_oil 0.10 reworks the import mechanism to support more syntax to make it more rusty, and test for item use before importing to determine which imports are modules and which are items, which allows: - use rust-style imports ``` #import bevy_pbr::{ pbr_functions::{alpha_discard as discard, apply_pbr_lighting}, mesh_bindings, } ``` - import partial paths: ``` #import part::of::path ... path::remainder::function(); ``` which will call to `part::of::path::remainder::function` - use fully qualified paths without importing: ``` // #import bevy_pbr::pbr_functions bevy_pbr::pbr_functions::pbr() ``` - use imported items without qualifying ``` #import bevy_pbr::pbr_functions::pbr // for backwards compatibility the old style is still supported: // #import bevy_pbr::pbr_functions pbr ... pbr() ``` - allows most imported items to end with `_` and numbers (naga_oil#30). still doesn't allow struct members to end with `_` or numbers but it's progress. - the vast majority of existing shader code will work without changes, but will emit "deprecated" warnings for old-style imports. these can be suppressed with the `allow-deprecated` feature. - partly breaks overrides (as far as i'm aware nobody uses these yet) - now overrides will only be applied if the overriding module is added as an additional import in the arguments to `Composer::make_naga_module` or `Composer::add_composable_module`. this is necessary to support determining whether imports are modules or items.
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#import bevy_pbr::prepass_io::VertexOutput
#else
update shader imports (#10180) # Objective - bump naga_oil to 0.10 - update shader imports to use rusty syntax ## Migration Guide naga_oil 0.10 reworks the import mechanism to support more syntax to make it more rusty, and test for item use before importing to determine which imports are modules and which are items, which allows: - use rust-style imports ``` #import bevy_pbr::{ pbr_functions::{alpha_discard as discard, apply_pbr_lighting}, mesh_bindings, } ``` - import partial paths: ``` #import part::of::path ... path::remainder::function(); ``` which will call to `part::of::path::remainder::function` - use fully qualified paths without importing: ``` // #import bevy_pbr::pbr_functions bevy_pbr::pbr_functions::pbr() ``` - use imported items without qualifying ``` #import bevy_pbr::pbr_functions::pbr // for backwards compatibility the old style is still supported: // #import bevy_pbr::pbr_functions pbr ... pbr() ``` - allows most imported items to end with `_` and numbers (naga_oil#30). still doesn't allow struct members to end with `_` or numbers but it's progress. - the vast majority of existing shader code will work without changes, but will emit "deprecated" warnings for old-style imports. these can be suppressed with the `allow-deprecated` feature. - partly breaks overrides (as far as i'm aware nobody uses these yet) - now overrides will only be applied if the overriding module is added as an additional import in the arguments to `Composer::make_naga_module` or `Composer::add_composable_module`. this is necessary to support determining whether imports are modules or items.
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#import bevy_pbr::forward_io::VertexOutput
#endif
// prepare a basic PbrInput from the vertex stage output, mesh binding and view binding
fn pbr_input_from_vertex_output(
in: VertexOutput,
is_front: bool,
double_sided: bool,
) -> pbr_types::PbrInput {
var pbr_input: pbr_types::PbrInput = pbr_types::pbr_input_new();
pbr_input.flags = mesh[in.instance_index].flags;
pbr_input.is_orthographic = view.projection[3].w == 1.0;
pbr_input.V = pbr_functions::calculate_view(in.world_position, pbr_input.is_orthographic);
pbr_input.frag_coord = in.position;
pbr_input.world_position = in.world_position;
#ifdef VERTEX_COLORS
pbr_input.material.base_color = in.color;
#endif
pbr_input.world_normal = pbr_functions::prepare_world_normal(
in.world_normal,
double_sided,
is_front,
);
#ifdef LOAD_PREPASS_NORMALS
update shader imports (#10180) # Objective - bump naga_oil to 0.10 - update shader imports to use rusty syntax ## Migration Guide naga_oil 0.10 reworks the import mechanism to support more syntax to make it more rusty, and test for item use before importing to determine which imports are modules and which are items, which allows: - use rust-style imports ``` #import bevy_pbr::{ pbr_functions::{alpha_discard as discard, apply_pbr_lighting}, mesh_bindings, } ``` - import partial paths: ``` #import part::of::path ... path::remainder::function(); ``` which will call to `part::of::path::remainder::function` - use fully qualified paths without importing: ``` // #import bevy_pbr::pbr_functions bevy_pbr::pbr_functions::pbr() ``` - use imported items without qualifying ``` #import bevy_pbr::pbr_functions::pbr // for backwards compatibility the old style is still supported: // #import bevy_pbr::pbr_functions pbr ... pbr() ``` - allows most imported items to end with `_` and numbers (naga_oil#30). still doesn't allow struct members to end with `_` or numbers but it's progress. - the vast majority of existing shader code will work without changes, but will emit "deprecated" warnings for old-style imports. these can be suppressed with the `allow-deprecated` feature. - partly breaks overrides (as far as i'm aware nobody uses these yet) - now overrides will only be applied if the overriding module is added as an additional import in the arguments to `Composer::make_naga_module` or `Composer::add_composable_module`. this is necessary to support determining whether imports are modules or items.
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pbr_input.N = prepass_utils::prepass_normal(in.position, 0u);
#else
pbr_input.N = normalize(pbr_input.world_normal);
#endif
return pbr_input;
}
// Prepare a full PbrInput by sampling all textures to resolve
// the material members
fn pbr_input_from_standard_material(
in: VertexOutput,
is_front: bool,
) -> pbr_types::PbrInput {
let double_sided = (pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_DOUBLE_SIDED_BIT) != 0u;
var pbr_input: pbr_types::PbrInput = pbr_input_from_vertex_output(in, is_front, double_sided);
pbr_input.material.flags = pbr_bindings::material.flags;
pbr_input.material.base_color *= pbr_bindings::material.base_color;
pbr_input.material.deferred_lighting_pass_id = pbr_bindings::material.deferred_lighting_pass_id;
#ifdef VERTEX_UVS
var uv = in.uv;
#ifdef VERTEX_TANGENTS
if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_DEPTH_MAP_BIT) != 0u) {
let V = pbr_input.V;
let N = in.world_normal;
let T = in.world_tangent.xyz;
let B = in.world_tangent.w * cross(N, T);
// Transform V from fragment to camera in world space to tangent space.
let Vt = vec3(dot(V, T), dot(V, B), dot(V, N));
uv = parallaxed_uv(
pbr_bindings::material.parallax_depth_scale,
pbr_bindings::material.max_parallax_layer_count,
pbr_bindings::material.max_relief_mapping_search_steps,
uv,
// Flip the direction of Vt to go toward the surface to make the
// parallax mapping algorithm easier to understand and reason
// about.
-Vt,
);
}
#endif // VERTEX_TANGENTS
if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_BASE_COLOR_TEXTURE_BIT) != 0u) {
pbr_input.material.base_color *= textureSampleBias(pbr_bindings::base_color_texture, pbr_bindings::base_color_sampler, uv, view.mip_bias);
}
#endif // VERTEX_UVS
pbr_input.material.flags = pbr_bindings::material.flags;
// NOTE: Unlit bit not set means == 0 is true, so the true case is if lit
if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_UNLIT_BIT) == 0u) {
pbr_input.material.reflectance = pbr_bindings::material.reflectance;
`StandardMaterial` Light Transmission (#8015) # Objective <img width="1920" alt="Screenshot 2023-04-26 at 01 07 34" src="https://user-images.githubusercontent.com/418473/234467578-0f34187b-5863-4ea1-88e9-7a6bb8ce8da3.png"> This PR adds both diffuse and specular light transmission capabilities to the `StandardMaterial`, with support for screen space refractions. This enables realistically representing a wide range of real-world materials, such as: - Glass; (Including frosted glass) - Transparent and translucent plastics; - Various liquids and gels; - Gemstones; - Marble; - Wax; - Paper; - Leaves; - Porcelain. Unlike existing support for transparency, light transmission does not rely on fixed function alpha blending, and therefore works with both `AlphaMode::Opaque` and `AlphaMode::Mask` materials. ## Solution - Introduces a number of transmission related fields in the `StandardMaterial`; - For specular transmission: - Adds logic to take a view main texture snapshot after the opaque phase; (in order to perform screen space refractions) - Introduces a new `Transmissive3d` phase to the renderer, to which all meshes with `transmission > 0.0` materials are sent. - Calculates a light exit point (of the approximate mesh volume) using `ior` and `thickness` properties - Samples the snapshot texture with an adaptive number of taps across a `roughness`-controlled radius enabling “blurry” refractions - For diffuse transmission: - Approximates transmitted diffuse light by using a second, flipped + displaced, diffuse-only Lambertian lobe for each light source. ## To Do - [x] Figure out where `fresnel_mix()` is taking place, if at all, and where `dielectric_specular` is being calculated, if at all, and update them to use the `ior` value (Not a blocker, just a nice-to-have for more correct BSDF) - To the _best of my knowledge, this is now taking place, after 964340cdd. The fresnel mix is actually "split" into two parts in our implementation, one `(1 - fresnel(...))` in the transmission, and `fresnel()` in the light implementations. A surface with more reflectance now will produce slightly dimmer transmission towards the grazing angle, as more of the light gets reflected. - [x] Add `transmission_texture` - [x] Add `diffuse_transmission_texture` - [x] Add `thickness_texture` - [x] Add `attenuation_distance` and `attenuation_color` - [x] Connect values to glTF loader - [x] `transmission` and `transmission_texture` - [x] `thickness` and `thickness_texture` - [x] `ior` - [ ] `diffuse_transmission` and `diffuse_transmission_texture` (needs upstream support in `gltf` crate, not a blocker) - [x] Add support for multiple screen space refraction “steps” - [x] Conditionally create no transmission snapshot texture at all if `steps == 0` - [x] Conditionally enable/disable screen space refraction transmission snapshots - [x] Read from depth pre-pass to prevent refracting pixels in front of the light exit point - [x] Use `interleaved_gradient_noise()` function for sampling blur in a way that benefits from TAA - [x] Drill down a TAA `#define`, tweak some aspects of the effect conditionally based on it - [x] Remove const array that's crashing under HLSL (unless a new `naga` release with https://github.com/gfx-rs/naga/pull/2496 comes out before we merge this) - [ ] Look into alternatives to the `switch` hack for dynamically indexing the const array (might not be needed, compilers seem to be decent at expanding it) - [ ] Add pipeline keys for gating transmission (do we really want/need this?) - [x] Tweak some material field/function names? ## A Note on Texture Packing _This was originally added as a comment to the `specular_transmission_texture`, `thickness_texture` and `diffuse_transmission_texture` documentation, I removed it since it was more confusing than helpful, and will likely be made redundant/will need to be updated once we have a better infrastructure for preprocessing assets_ Due to how channels are mapped, you can more efficiently use a single shared texture image for configuring the following: - R - `specular_transmission_texture` - G - `thickness_texture` - B - _unused_ - A - `diffuse_transmission_texture` The `KHR_materials_diffuse_transmission` glTF extension also defines a `diffuseTransmissionColorTexture`, that _we don't currently support_. One might choose to pack the intensity and color textures together, using RGB for the color and A for the intensity, in which case this packing advice doesn't really apply. --- ## Changelog - Added a new `Transmissive3d` render phase for rendering specular transmissive materials with screen space refractions - Added rendering support for transmitted environment map light on the `StandardMaterial` as a fallback for screen space refractions - Added `diffuse_transmission`, `specular_transmission`, `thickness`, `ior`, `attenuation_distance` and `attenuation_color` to the `StandardMaterial` - Added `diffuse_transmission_texture`, `specular_transmission_texture`, `thickness_texture` to the `StandardMaterial`, gated behind a new `pbr_transmission_textures` cargo feature (off by default, for maximum hardware compatibility) - Added `Camera3d::screen_space_specular_transmission_steps` for controlling the number of “layers of transparency” rendered for transmissive objects - Added a `TransmittedShadowReceiver` component for enabling shadows in (diffusely) transmitted light. (disabled by default, as it requires carefully setting up the `thickness` to avoid self-shadow artifacts) - Added support for the `KHR_materials_transmission`, `KHR_materials_ior` and `KHR_materials_volume` glTF extensions - Renamed items related to temporal jitter for greater consistency ## Migration Guide - `SsaoPipelineKey::temporal_noise` has been renamed to `SsaoPipelineKey::temporal_jitter` - The `TAA` shader def (controlled by the presence of the `TemporalAntiAliasSettings` component in the camera) has been replaced with the `TEMPORAL_JITTER` shader def (controlled by the presence of the `TemporalJitter` component in the camera) - `MeshPipelineKey::TAA` has been replaced by `MeshPipelineKey::TEMPORAL_JITTER` - The `TEMPORAL_NOISE` shader def has been consolidated with `TEMPORAL_JITTER`
2023-10-31 20:59:02 +00:00
pbr_input.material.ior = pbr_bindings::material.ior;
pbr_input.material.attenuation_color = pbr_bindings::material.attenuation_color;
pbr_input.material.attenuation_distance = pbr_bindings::material.attenuation_distance;
pbr_input.material.alpha_cutoff = pbr_bindings::material.alpha_cutoff;
`StandardMaterial` Light Transmission (#8015) # Objective <img width="1920" alt="Screenshot 2023-04-26 at 01 07 34" src="https://user-images.githubusercontent.com/418473/234467578-0f34187b-5863-4ea1-88e9-7a6bb8ce8da3.png"> This PR adds both diffuse and specular light transmission capabilities to the `StandardMaterial`, with support for screen space refractions. This enables realistically representing a wide range of real-world materials, such as: - Glass; (Including frosted glass) - Transparent and translucent plastics; - Various liquids and gels; - Gemstones; - Marble; - Wax; - Paper; - Leaves; - Porcelain. Unlike existing support for transparency, light transmission does not rely on fixed function alpha blending, and therefore works with both `AlphaMode::Opaque` and `AlphaMode::Mask` materials. ## Solution - Introduces a number of transmission related fields in the `StandardMaterial`; - For specular transmission: - Adds logic to take a view main texture snapshot after the opaque phase; (in order to perform screen space refractions) - Introduces a new `Transmissive3d` phase to the renderer, to which all meshes with `transmission > 0.0` materials are sent. - Calculates a light exit point (of the approximate mesh volume) using `ior` and `thickness` properties - Samples the snapshot texture with an adaptive number of taps across a `roughness`-controlled radius enabling “blurry” refractions - For diffuse transmission: - Approximates transmitted diffuse light by using a second, flipped + displaced, diffuse-only Lambertian lobe for each light source. ## To Do - [x] Figure out where `fresnel_mix()` is taking place, if at all, and where `dielectric_specular` is being calculated, if at all, and update them to use the `ior` value (Not a blocker, just a nice-to-have for more correct BSDF) - To the _best of my knowledge, this is now taking place, after 964340cdd. The fresnel mix is actually "split" into two parts in our implementation, one `(1 - fresnel(...))` in the transmission, and `fresnel()` in the light implementations. A surface with more reflectance now will produce slightly dimmer transmission towards the grazing angle, as more of the light gets reflected. - [x] Add `transmission_texture` - [x] Add `diffuse_transmission_texture` - [x] Add `thickness_texture` - [x] Add `attenuation_distance` and `attenuation_color` - [x] Connect values to glTF loader - [x] `transmission` and `transmission_texture` - [x] `thickness` and `thickness_texture` - [x] `ior` - [ ] `diffuse_transmission` and `diffuse_transmission_texture` (needs upstream support in `gltf` crate, not a blocker) - [x] Add support for multiple screen space refraction “steps” - [x] Conditionally create no transmission snapshot texture at all if `steps == 0` - [x] Conditionally enable/disable screen space refraction transmission snapshots - [x] Read from depth pre-pass to prevent refracting pixels in front of the light exit point - [x] Use `interleaved_gradient_noise()` function for sampling blur in a way that benefits from TAA - [x] Drill down a TAA `#define`, tweak some aspects of the effect conditionally based on it - [x] Remove const array that's crashing under HLSL (unless a new `naga` release with https://github.com/gfx-rs/naga/pull/2496 comes out before we merge this) - [ ] Look into alternatives to the `switch` hack for dynamically indexing the const array (might not be needed, compilers seem to be decent at expanding it) - [ ] Add pipeline keys for gating transmission (do we really want/need this?) - [x] Tweak some material field/function names? ## A Note on Texture Packing _This was originally added as a comment to the `specular_transmission_texture`, `thickness_texture` and `diffuse_transmission_texture` documentation, I removed it since it was more confusing than helpful, and will likely be made redundant/will need to be updated once we have a better infrastructure for preprocessing assets_ Due to how channels are mapped, you can more efficiently use a single shared texture image for configuring the following: - R - `specular_transmission_texture` - G - `thickness_texture` - B - _unused_ - A - `diffuse_transmission_texture` The `KHR_materials_diffuse_transmission` glTF extension also defines a `diffuseTransmissionColorTexture`, that _we don't currently support_. One might choose to pack the intensity and color textures together, using RGB for the color and A for the intensity, in which case this packing advice doesn't really apply. --- ## Changelog - Added a new `Transmissive3d` render phase for rendering specular transmissive materials with screen space refractions - Added rendering support for transmitted environment map light on the `StandardMaterial` as a fallback for screen space refractions - Added `diffuse_transmission`, `specular_transmission`, `thickness`, `ior`, `attenuation_distance` and `attenuation_color` to the `StandardMaterial` - Added `diffuse_transmission_texture`, `specular_transmission_texture`, `thickness_texture` to the `StandardMaterial`, gated behind a new `pbr_transmission_textures` cargo feature (off by default, for maximum hardware compatibility) - Added `Camera3d::screen_space_specular_transmission_steps` for controlling the number of “layers of transparency” rendered for transmissive objects - Added a `TransmittedShadowReceiver` component for enabling shadows in (diffusely) transmitted light. (disabled by default, as it requires carefully setting up the `thickness` to avoid self-shadow artifacts) - Added support for the `KHR_materials_transmission`, `KHR_materials_ior` and `KHR_materials_volume` glTF extensions - Renamed items related to temporal jitter for greater consistency ## Migration Guide - `SsaoPipelineKey::temporal_noise` has been renamed to `SsaoPipelineKey::temporal_jitter` - The `TAA` shader def (controlled by the presence of the `TemporalAntiAliasSettings` component in the camera) has been replaced with the `TEMPORAL_JITTER` shader def (controlled by the presence of the `TemporalJitter` component in the camera) - `MeshPipelineKey::TAA` has been replaced by `MeshPipelineKey::TEMPORAL_JITTER` - The `TEMPORAL_NOISE` shader def has been consolidated with `TEMPORAL_JITTER`
2023-10-31 20:59:02 +00:00
// emissive
// TODO use .a for exposure compensation in HDR
var emissive: vec4<f32> = pbr_bindings::material.emissive;
#ifdef VERTEX_UVS
if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_EMISSIVE_TEXTURE_BIT) != 0u) {
emissive = vec4<f32>(emissive.rgb * textureSampleBias(pbr_bindings::emissive_texture, pbr_bindings::emissive_sampler, uv, view.mip_bias).rgb, 1.0);
}
#endif
pbr_input.material.emissive = emissive;
// metallic and perceptual roughness
var metallic: f32 = pbr_bindings::material.metallic;
var perceptual_roughness: f32 = pbr_bindings::material.perceptual_roughness;
#ifdef VERTEX_UVS
if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_METALLIC_ROUGHNESS_TEXTURE_BIT) != 0u) {
let metallic_roughness = textureSampleBias(pbr_bindings::metallic_roughness_texture, pbr_bindings::metallic_roughness_sampler, uv, view.mip_bias);
// Sampling from GLTF standard channels for now
metallic *= metallic_roughness.b;
perceptual_roughness *= metallic_roughness.g;
}
#endif
pbr_input.material.metallic = metallic;
pbr_input.material.perceptual_roughness = perceptual_roughness;
`StandardMaterial` Light Transmission (#8015) # Objective <img width="1920" alt="Screenshot 2023-04-26 at 01 07 34" src="https://user-images.githubusercontent.com/418473/234467578-0f34187b-5863-4ea1-88e9-7a6bb8ce8da3.png"> This PR adds both diffuse and specular light transmission capabilities to the `StandardMaterial`, with support for screen space refractions. This enables realistically representing a wide range of real-world materials, such as: - Glass; (Including frosted glass) - Transparent and translucent plastics; - Various liquids and gels; - Gemstones; - Marble; - Wax; - Paper; - Leaves; - Porcelain. Unlike existing support for transparency, light transmission does not rely on fixed function alpha blending, and therefore works with both `AlphaMode::Opaque` and `AlphaMode::Mask` materials. ## Solution - Introduces a number of transmission related fields in the `StandardMaterial`; - For specular transmission: - Adds logic to take a view main texture snapshot after the opaque phase; (in order to perform screen space refractions) - Introduces a new `Transmissive3d` phase to the renderer, to which all meshes with `transmission > 0.0` materials are sent. - Calculates a light exit point (of the approximate mesh volume) using `ior` and `thickness` properties - Samples the snapshot texture with an adaptive number of taps across a `roughness`-controlled radius enabling “blurry” refractions - For diffuse transmission: - Approximates transmitted diffuse light by using a second, flipped + displaced, diffuse-only Lambertian lobe for each light source. ## To Do - [x] Figure out where `fresnel_mix()` is taking place, if at all, and where `dielectric_specular` is being calculated, if at all, and update them to use the `ior` value (Not a blocker, just a nice-to-have for more correct BSDF) - To the _best of my knowledge, this is now taking place, after 964340cdd. The fresnel mix is actually "split" into two parts in our implementation, one `(1 - fresnel(...))` in the transmission, and `fresnel()` in the light implementations. A surface with more reflectance now will produce slightly dimmer transmission towards the grazing angle, as more of the light gets reflected. - [x] Add `transmission_texture` - [x] Add `diffuse_transmission_texture` - [x] Add `thickness_texture` - [x] Add `attenuation_distance` and `attenuation_color` - [x] Connect values to glTF loader - [x] `transmission` and `transmission_texture` - [x] `thickness` and `thickness_texture` - [x] `ior` - [ ] `diffuse_transmission` and `diffuse_transmission_texture` (needs upstream support in `gltf` crate, not a blocker) - [x] Add support for multiple screen space refraction “steps” - [x] Conditionally create no transmission snapshot texture at all if `steps == 0` - [x] Conditionally enable/disable screen space refraction transmission snapshots - [x] Read from depth pre-pass to prevent refracting pixels in front of the light exit point - [x] Use `interleaved_gradient_noise()` function for sampling blur in a way that benefits from TAA - [x] Drill down a TAA `#define`, tweak some aspects of the effect conditionally based on it - [x] Remove const array that's crashing under HLSL (unless a new `naga` release with https://github.com/gfx-rs/naga/pull/2496 comes out before we merge this) - [ ] Look into alternatives to the `switch` hack for dynamically indexing the const array (might not be needed, compilers seem to be decent at expanding it) - [ ] Add pipeline keys for gating transmission (do we really want/need this?) - [x] Tweak some material field/function names? ## A Note on Texture Packing _This was originally added as a comment to the `specular_transmission_texture`, `thickness_texture` and `diffuse_transmission_texture` documentation, I removed it since it was more confusing than helpful, and will likely be made redundant/will need to be updated once we have a better infrastructure for preprocessing assets_ Due to how channels are mapped, you can more efficiently use a single shared texture image for configuring the following: - R - `specular_transmission_texture` - G - `thickness_texture` - B - _unused_ - A - `diffuse_transmission_texture` The `KHR_materials_diffuse_transmission` glTF extension also defines a `diffuseTransmissionColorTexture`, that _we don't currently support_. One might choose to pack the intensity and color textures together, using RGB for the color and A for the intensity, in which case this packing advice doesn't really apply. --- ## Changelog - Added a new `Transmissive3d` render phase for rendering specular transmissive materials with screen space refractions - Added rendering support for transmitted environment map light on the `StandardMaterial` as a fallback for screen space refractions - Added `diffuse_transmission`, `specular_transmission`, `thickness`, `ior`, `attenuation_distance` and `attenuation_color` to the `StandardMaterial` - Added `diffuse_transmission_texture`, `specular_transmission_texture`, `thickness_texture` to the `StandardMaterial`, gated behind a new `pbr_transmission_textures` cargo feature (off by default, for maximum hardware compatibility) - Added `Camera3d::screen_space_specular_transmission_steps` for controlling the number of “layers of transparency” rendered for transmissive objects - Added a `TransmittedShadowReceiver` component for enabling shadows in (diffusely) transmitted light. (disabled by default, as it requires carefully setting up the `thickness` to avoid self-shadow artifacts) - Added support for the `KHR_materials_transmission`, `KHR_materials_ior` and `KHR_materials_volume` glTF extensions - Renamed items related to temporal jitter for greater consistency ## Migration Guide - `SsaoPipelineKey::temporal_noise` has been renamed to `SsaoPipelineKey::temporal_jitter` - The `TAA` shader def (controlled by the presence of the `TemporalAntiAliasSettings` component in the camera) has been replaced with the `TEMPORAL_JITTER` shader def (controlled by the presence of the `TemporalJitter` component in the camera) - `MeshPipelineKey::TAA` has been replaced by `MeshPipelineKey::TEMPORAL_JITTER` - The `TEMPORAL_NOISE` shader def has been consolidated with `TEMPORAL_JITTER`
2023-10-31 20:59:02 +00:00
var specular_transmission: f32 = pbr_bindings::material.specular_transmission;
#ifdef PBR_TRANSMISSION_TEXTURES_SUPPORTED
if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_SPECULAR_TRANSMISSION_TEXTURE_BIT) != 0u) {
specular_transmission *= textureSample(pbr_bindings::specular_transmission_texture, pbr_bindings::specular_transmission_sampler, uv).r;
}
#endif
pbr_input.material.specular_transmission = specular_transmission;
var thickness: f32 = pbr_bindings::material.thickness;
#ifdef PBR_TRANSMISSION_TEXTURES_SUPPORTED
if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_THICKNESS_TEXTURE_BIT) != 0u) {
thickness *= textureSample(pbr_bindings::thickness_texture, pbr_bindings::thickness_sampler, uv).g;
}
#endif
// scale thickness, accounting for non-uniform scaling (e.g. a “squished” mesh)
thickness *= length(
(transpose(mesh[in.instance_index].model) * vec4(pbr_input.N, 0.0)).xyz
);
pbr_input.material.thickness = thickness;
var diffuse_transmission = pbr_bindings::material.diffuse_transmission;
#ifdef PBR_TRANSMISSION_TEXTURES_SUPPORTED
if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_DIFFUSE_TRANSMISSION_TEXTURE_BIT) != 0u) {
diffuse_transmission *= textureSample(pbr_bindings::diffuse_transmission_texture, pbr_bindings::diffuse_transmission_sampler, uv).a;
}
#endif
pbr_input.material.diffuse_transmission = diffuse_transmission;
// occlusion
// TODO: Split into diffuse/specular occlusion?
var occlusion: vec3<f32> = vec3(1.0);
#ifdef VERTEX_UVS
if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_OCCLUSION_TEXTURE_BIT) != 0u) {
occlusion = vec3(textureSampleBias(pbr_bindings::occlusion_texture, pbr_bindings::occlusion_sampler, uv, view.mip_bias).r);
}
#endif
#ifdef SCREEN_SPACE_AMBIENT_OCCLUSION
let ssao = textureLoad(screen_space_ambient_occlusion_texture, vec2<i32>(in.position.xy), 0i).r;
let ssao_multibounce = gtao_multibounce(ssao, pbr_input.material.base_color.rgb);
occlusion = min(occlusion, ssao_multibounce);
#endif
pbr_input.occlusion = occlusion;
// N (normal vector)
#ifndef LOAD_PREPASS_NORMALS
pbr_input.N = pbr_functions::apply_normal_mapping(
pbr_bindings::material.flags,
pbr_input.world_normal,
double_sided,
is_front,
#ifdef VERTEX_TANGENTS
#ifdef STANDARDMATERIAL_NORMAL_MAP
in.world_tangent,
#endif
#endif
#ifdef VERTEX_UVS
uv,
#endif
view.mip_bias,
);
#endif
#ifdef LIGHTMAP
pbr_input.lightmap_light = lightmap(
in.uv_b,
pbr_bindings::material.lightmap_exposure,
in.instance_index);
#endif
}
return pbr_input;
}