bevy/crates/bevy_pbr/src/material.rs

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use crate::{AlphaMode, PbrPipeline, StandardMaterialFlags};
use bevy_app::{App, Plugin};
use bevy_asset::{AddAsset, Handle, HandleUntyped};
use bevy_ecs::system::{lifetimeless::SRes, SystemParamItem};
use bevy_math::Vec4;
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use bevy_reflect::TypeUuid;
use bevy_render::{
color::Color,
render_asset::{PrepareAssetError, RenderAsset, RenderAssetPlugin, RenderAssets},
render_resource::{BindGroup, Buffer, BufferInitDescriptor, BufferUsages},
renderer::RenderDevice,
texture::Image,
};
use crevice::std140::{AsStd140, Std140};
use wgpu::{BindGroupDescriptor, BindGroupEntry, BindingResource};
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pub const DEFAULT_STANDARD_MATERIAL_HANDLE: HandleUntyped =
HandleUntyped::weak_from_u64(StandardMaterial::TYPE_UUID, 13142262394054731189);
/// A material with "standard" properties used in PBR lighting
/// Standard property values with pictures here
/// <https://google.github.io/filament/Material%20Properties.pdf>.
///
/// May be created directly from a [`Color`] or an [`Image`].
#[derive(Debug, Clone, TypeUuid)]
#[uuid = "7494888b-c082-457b-aacf-517228cc0c22"]
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pub struct StandardMaterial {
/// Doubles as diffuse albedo for non-metallic, specular for metallic and a mix for everything
/// in between. If used together with a base_color_texture, this is factored into the final
/// base color as `base_color * base_color_texture_value`
pub base_color: Color,
pub base_color_texture: Option<Handle<Image>>,
// Use a color for user friendliness even though we technically don't use the alpha channel
// Might be used in the future for exposure correction in HDR
pub emissive: Color,
pub emissive_texture: Option<Handle<Image>>,
/// Linear perceptual roughness, clamped to [0.089, 1.0] in the shader
/// Defaults to minimum of 0.089
/// If used together with a roughness/metallic texture, this is factored into the final base
/// color as `roughness * roughness_texture_value`
pub perceptual_roughness: f32,
/// From [0.0, 1.0], dielectric to pure metallic
/// If used together with a roughness/metallic texture, this is factored into the final base
/// color as `metallic * metallic_texture_value`
pub metallic: f32,
pub metallic_roughness_texture: Option<Handle<Image>>,
/// Specular intensity for non-metals on a linear scale of [0.0, 1.0]
/// defaults to 0.5 which is mapped to 4% reflectance in the shader
pub reflectance: f32,
pub normal_map_texture: Option<Handle<Image>>,
pub occlusion_texture: Option<Handle<Image>>,
pub double_sided: bool,
pub unlit: bool,
pub alpha_mode: AlphaMode,
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}
impl Default for StandardMaterial {
fn default() -> Self {
StandardMaterial {
base_color: Color::rgb(1.0, 1.0, 1.0),
base_color_texture: None,
emissive: Color::BLACK,
emissive_texture: None,
// This is the minimum the roughness is clamped to in shader code
// See <https://google.github.io/filament/Filament.html#materialsystem/parameterization/>
// It's the minimum floating point value that won't be rounded down to 0 in the
// calculations used. Although technically for 32-bit floats, 0.045 could be
// used.
perceptual_roughness: 0.089,
// Few materials are purely dielectric or metallic
// This is just a default for mostly-dielectric
metallic: 0.01,
metallic_roughness_texture: None,
// Minimum real-world reflectance is 2%, most materials between 2-5%
// Expressed in a linear scale and equivalent to 4% reflectance see
// <https://google.github.io/filament/Material%20Properties.pdf>
reflectance: 0.5,
occlusion_texture: None,
normal_map_texture: None,
double_sided: false,
unlit: false,
alpha_mode: AlphaMode::Opaque,
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}
}
}
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impl From<Color> for StandardMaterial {
fn from(color: Color) -> Self {
StandardMaterial {
base_color: color,
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..Default::default()
}
}
}
impl From<Handle<Image>> for StandardMaterial {
fn from(texture: Handle<Image>) -> Self {
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StandardMaterial {
base_color_texture: Some(texture),
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..Default::default()
}
}
}
/// The GPU representation of the uniform data of a [`StandardMaterial`].
#[derive(Clone, Default, AsStd140)]
pub struct StandardMaterialUniformData {
/// Doubles as diffuse albedo for non-metallic, specular for metallic and a mix for everything
/// in between.
pub base_color: Vec4,
// Use a color for user friendliness even though we technically don't use the alpha channel
// Might be used in the future for exposure correction in HDR
pub emissive: Vec4,
/// Linear perceptual roughness, clamped to [0.089, 1.0] in the shader
/// Defaults to minimum of 0.089
pub roughness: f32,
/// From [0.0, 1.0], dielectric to pure metallic
pub metallic: f32,
/// Specular intensity for non-metals on a linear scale of [0.0, 1.0]
/// defaults to 0.5 which is mapped to 4% reflectance in the shader
pub reflectance: f32,
pub flags: u32,
/// When the alpha mode mask flag is set, any base color alpha above this cutoff means fully opaque,
/// and any below means fully transparent.
pub alpha_cutoff: f32,
}
/// This plugin adds the [`StandardMaterial`] asset to the app.
pub struct StandardMaterialPlugin;
impl Plugin for StandardMaterialPlugin {
fn build(&self, app: &mut App) {
app.add_plugin(RenderAssetPlugin::<StandardMaterial>::default())
.add_asset::<StandardMaterial>();
}
}
/// The GPU representation of a [`StandardMaterial`].
#[derive(Debug, Clone)]
pub struct GpuStandardMaterial {
/// A buffer containing the [`StandardMaterialUniformData`] of the material.
pub buffer: Buffer,
/// The bind group specifying how the [`StandardMaterialUniformData`] and
/// all the textures of the material are bound.
pub bind_group: BindGroup,
pub has_normal_map: bool,
pub flags: StandardMaterialFlags,
pub base_color_texture: Option<Handle<Image>>,
pub alpha_mode: AlphaMode,
}
impl RenderAsset for StandardMaterial {
type ExtractedAsset = StandardMaterial;
type PreparedAsset = GpuStandardMaterial;
type Param = (
SRes<RenderDevice>,
SRes<PbrPipeline>,
SRes<RenderAssets<Image>>,
);
fn extract_asset(&self) -> Self::ExtractedAsset {
self.clone()
}
fn prepare_asset(
material: Self::ExtractedAsset,
(render_device, pbr_pipeline, gpu_images): &mut SystemParamItem<Self::Param>,
) -> Result<Self::PreparedAsset, PrepareAssetError<Self::ExtractedAsset>> {
let (base_color_texture_view, base_color_sampler) = if let Some(result) = pbr_pipeline
.mesh_pipeline
.get_image_texture(gpu_images, &material.base_color_texture)
{
result
} else {
return Err(PrepareAssetError::RetryNextUpdate(material));
};
let (emissive_texture_view, emissive_sampler) = if let Some(result) = pbr_pipeline
.mesh_pipeline
.get_image_texture(gpu_images, &material.emissive_texture)
{
result
} else {
return Err(PrepareAssetError::RetryNextUpdate(material));
};
let (metallic_roughness_texture_view, metallic_roughness_sampler) = if let Some(result) =
pbr_pipeline
.mesh_pipeline
.get_image_texture(gpu_images, &material.metallic_roughness_texture)
{
result
} else {
return Err(PrepareAssetError::RetryNextUpdate(material));
};
let (normal_map_texture_view, normal_map_sampler) = if let Some(result) = pbr_pipeline
.mesh_pipeline
.get_image_texture(gpu_images, &material.normal_map_texture)
{
result
} else {
return Err(PrepareAssetError::RetryNextUpdate(material));
};
let (occlusion_texture_view, occlusion_sampler) = if let Some(result) = pbr_pipeline
.mesh_pipeline
.get_image_texture(gpu_images, &material.occlusion_texture)
{
result
} else {
return Err(PrepareAssetError::RetryNextUpdate(material));
};
let mut flags = StandardMaterialFlags::NONE;
if material.base_color_texture.is_some() {
flags |= StandardMaterialFlags::BASE_COLOR_TEXTURE;
}
if material.emissive_texture.is_some() {
flags |= StandardMaterialFlags::EMISSIVE_TEXTURE;
}
if material.metallic_roughness_texture.is_some() {
flags |= StandardMaterialFlags::METALLIC_ROUGHNESS_TEXTURE;
}
if material.occlusion_texture.is_some() {
flags |= StandardMaterialFlags::OCCLUSION_TEXTURE;
}
if material.double_sided {
flags |= StandardMaterialFlags::DOUBLE_SIDED;
}
if material.unlit {
flags |= StandardMaterialFlags::UNLIT;
}
let has_normal_map = material.normal_map_texture.is_some();
// NOTE: 0.5 is from the glTF default - do we want this?
let mut alpha_cutoff = 0.5;
match material.alpha_mode {
AlphaMode::Opaque => flags |= StandardMaterialFlags::ALPHA_MODE_OPAQUE,
AlphaMode::Mask(c) => {
alpha_cutoff = c;
flags |= StandardMaterialFlags::ALPHA_MODE_MASK
}
AlphaMode::Blend => flags |= StandardMaterialFlags::ALPHA_MODE_BLEND,
};
let value = StandardMaterialUniformData {
base_color: material.base_color.as_linear_rgba_f32().into(),
emissive: material.emissive.into(),
roughness: material.perceptual_roughness,
metallic: material.metallic,
reflectance: material.reflectance,
flags: flags.bits(),
alpha_cutoff,
};
let value_std140 = value.as_std140();
let buffer = render_device.create_buffer_with_data(&BufferInitDescriptor {
label: Some("pbr_standard_material_uniform_buffer"),
usage: BufferUsages::UNIFORM | BufferUsages::COPY_DST,
contents: value_std140.as_bytes(),
});
let bind_group = render_device.create_bind_group(&BindGroupDescriptor {
entries: &[
BindGroupEntry {
binding: 0,
resource: buffer.as_entire_binding(),
},
BindGroupEntry {
binding: 1,
resource: BindingResource::TextureView(base_color_texture_view),
},
BindGroupEntry {
binding: 2,
resource: BindingResource::Sampler(base_color_sampler),
},
BindGroupEntry {
binding: 3,
resource: BindingResource::TextureView(emissive_texture_view),
},
BindGroupEntry {
binding: 4,
resource: BindingResource::Sampler(emissive_sampler),
},
BindGroupEntry {
binding: 5,
resource: BindingResource::TextureView(metallic_roughness_texture_view),
},
BindGroupEntry {
binding: 6,
resource: BindingResource::Sampler(metallic_roughness_sampler),
},
BindGroupEntry {
binding: 7,
resource: BindingResource::TextureView(occlusion_texture_view),
},
BindGroupEntry {
binding: 8,
resource: BindingResource::Sampler(occlusion_sampler),
},
BindGroupEntry {
binding: 9,
resource: BindingResource::TextureView(normal_map_texture_view),
},
BindGroupEntry {
binding: 10,
resource: BindingResource::Sampler(normal_map_sampler),
},
],
label: Some("pbr_standard_material_bind_group"),
layout: &pbr_pipeline.material_layout,
});
Ok(GpuStandardMaterial {
buffer,
bind_group,
flags,
has_normal_map,
base_color_texture: material.base_color_texture,
alpha_mode: material.alpha_mode,
})
}
}