wde_pbr/deferred/pbr_material.rs
1use bevy::{
2 ecs::system::{SystemParamItem, lifetimeless::SRes},
3 prelude::*
4};
5use wde_renderer::prelude::*;
6
7use crate::prelude::PbrBatchesMarker;
8
9/// Marker component to indicate that an entity's transform should be included in the [PbrSsboTransform] updates.
10/// This automatically adds the [PbrBatchesMarker] (and thus the [PbrSsboTransformMarker]) to the entity.
11#[derive(Component, Reflect, Clone)]
12#[reflect(Component)]
13#[require(PbrBatchesMarker)]
14pub struct PbrMaterial3d<T: RenderBinding + Asset>(pub Handle<T>);
15
16/// Uniform structure for PBR material data.
17///
18/// The structure sent to the GPU is the following :
19/// ```wgsl
20/// struct Material3dUniform {
21/// flags: vec4<f32>, // Flags indicating material textures (1.0 = present, 0.0 = absent) - albedo, metallic-roughness, normal, occlusion
22/// albedo: vec4<f32>, // Albedo color of the material (r, g, b)
23/// metallic: f32, // Metallic intensity of the material
24/// roughness: f32, // Roughness intensity of the material
25/// _padding: vec2<f32>, // Unused padding to align to 16 bytes
26/// };
27///
28/// @group(2) @binding(0) var<uniform> pbr_material: PbrMaterialUniform; /// Material uniform buffer
29/// @group(2) @binding(1) var albedo_texture: texture_2d<f32>; /// Albedo texture (r, g, b)
30/// @group(2) @binding(2) var albedo_sampler: sampler; /// Albedo texture sampler
31/// @group(2) @binding(3) var metallic_roughness_texture: texture_2d<f32>; /// Metallic-roughness texture (b = metallic, g = roughness)
32/// @group(2) @binding(4) var metallic_roughness_sampler: sampler; /// Metallic-roughness texture sampler
33/// @group(2) @binding(5) var normal_texture: texture_2d<f32>; /// Normal texture (x, y, z)
34/// @group(2) @binding(6) var normal_sampler: sampler; /// Normal texture sampler
35/// @group(2) @binding(7) var occlusion_texture: texture_2d<f32>; /// Occlusion texture (r)
36/// @group(2) @binding(8) var occlusion_sampler: sampler; /// Occlusion texture sampler
37/// ```
38#[repr(C)]
39#[derive(Default, Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
40pub(crate) struct PbrMaterialUniform {
41 /// Flags indicating material textures (1.0 = present, 0.0 = absent) - albedo, metallic-roughness, normal, occlusion
42 pub flags: [f32; 4],
43 /// Albedo color of the material (r, g, b).
44 pub albedo: [f32; 4],
45 /// Metallic intensity of the material.
46 pub metallic: f32,
47 /// Roughness intensity of the material.
48 pub roughness: f32,
49 /// Unused padding to align to 16 bytes.
50 _padding: [f32; 2]
51}
52
53/// How a [PbrMaterial] is composited.
54#[derive(Default, Debug, Clone, Copy, PartialEq, Eq, Reflect)]
55pub enum PbrAlphaMode {
56 /// Written to the G-buffer and lit by the deferred lighting pass.
57 #[default]
58 Opaque,
59 /// Forward-lit and alpha-blended in the transparent pass. Does not cast shadows.
60 Blend
61}
62
63/// Describes a physically based rendering material.
64/// It contains the material properties such as albedo color, metallic and roughness intensity, as well as the textures for these properties. It also contains a uniform buffer that is automatically created and updated with the material data, which can be used in the shader to access the material properties.
65/// The [PbrMaterial3d] component is a wrapper around a handle to a [PbrMaterial] asset, which also adds the [PbrSsboTransformMarker] to the entity, indicating that its transform should be included in the [PbrSsboTransform](crate::prelude::PbrSsboTransform) updates.
66#[derive(Asset, Clone, TypePath)]
67pub struct PbrMaterial {
68 pub label: String,
69
70 /// The albedo color of the material instance (r, g, b).
71 /// The alpha channel is the opacity when `alpha_mode` is [PbrAlphaMode::Blend], unused otherwise.
72 pub albedo: (f32, f32, f32, f32),
73 /// The albedo texture of the material instance. If `None`, the material will use the albedo color.
74 pub albedo_t: Option<Handle<Texture>>,
75
76 /// The metallic intensity of the material instance.
77 pub metallic: f32,
78 /// The roughness intensity of the material instance.
79 pub roughness: f32,
80 /// The metallic-roughness texture of the material instance. If `None`, the material will use the metallic and roughness scalar intensity.
81 /// The metallic value is stored in the blue channel, and the roughness value is stored in the green channel.
82 pub metallic_roughness_t: Option<Handle<Texture>>,
83
84 /// The normal texture of the material instance.
85 /// The normal map is expected to be in tangent space.
86 /// The alpha channel is unused.
87 pub normal_t: Option<Handle<Texture>>,
88 /// The occlusion texture of the material instance.
89 /// The occlusion value is stored in the red channel.
90 pub occlusion_t: Option<Handle<Texture>>,
91
92 /// An optional stencil value to set the stencil buffer to when rendering the material.
93 pub stencil_value: Option<u32>,
94
95 /// Whether the material is drawn opaque in the G-buffer or alpha-blended in the transparent pass.
96 pub alpha_mode: PbrAlphaMode,
97
98 /// The buffer containing the material data. It is automatically created and updated if not set.
99 pub uniform_buffer: Option<Handle<Buffer>>,
100 /// Uniform bytes last written to `uniform_buffer`, so `describe` (which reruns on every retry
101 /// attempt, not just on an actual material change) doesn't recreate the buffer - and orphan a
102 /// not-yet-ready one - on every attempt.
103 pub last_uniform: Option<Vec<u8>>
104}
105impl Default for PbrMaterial {
106 fn default() -> Self {
107 PbrMaterial {
108 label: "pbr-material".to_string(),
109
110 albedo: (1.0, 1.0, 1.0, 0.0),
111 albedo_t: None,
112
113 metallic: 1.0,
114 roughness: 1.0,
115 metallic_roughness_t: None,
116
117 normal_t: None,
118 occlusion_t: None,
119
120 stencil_value: None,
121
122 alpha_mode: PbrAlphaMode::Opaque,
123
124 uniform_buffer: None,
125 last_uniform: None
126 }
127 }
128}
129impl RenderBinding for PbrMaterial {
130 type Params = (SRes<AssetServer>, SRes<PlaceholderTexture>);
131
132 fn describe(
133 &mut self,
134 (asset_server, placeholder_tex): &SystemParamItem<Self::Params>,
135 builder: &mut RenderBindingBuilder
136 ) {
137 // Create the uniform buffer
138 let uniform = PbrMaterialUniform {
139 flags: [
140 if self.albedo_t.is_some() { 1.0 } else { 0.0 },
141 if self.metallic_roughness_t.is_some() {
142 1.0
143 } else {
144 0.0
145 },
146 if self.normal_t.is_some() { 1.0 } else { 0.0 },
147 if self.occlusion_t.is_some() { 1.0 } else { 0.0 }
148 ],
149 albedo: [self.albedo.0, self.albedo.1, self.albedo.2, self.albedo.3],
150 metallic: self.metallic,
151 roughness: self.roughness,
152 _padding: [0.0, 0.0]
153 };
154 // `describe` reruns on every retry attempt (not just when the material asset actually
155 // changed) - recreating the buffer unconditionally used to orphan a not-yet-ready one on
156 // every attempt, so it could never converge. Only recreating it when the uniform content
157 // actually changed keeps a pending buffer stable across retries, while still refreshing a
158 // real change (e.g. `albedo_t` set after the first `describe` call used to leave
159 // `flags.x` at 0 forever).
160 let content = bytemuck::cast_slice(&[uniform]).to_vec();
161 if self.uniform_buffer.is_none() || self.last_uniform.as_deref() != Some(&content[..]) {
162 let uniform_handle = asset_server.add(Buffer {
163 label: format!("{}-uniform-buffer", self.label),
164 size: std::mem::size_of::<PbrMaterialUniform>(),
165 usage: BufferUsage::UNIFORM | BufferUsage::COPY_DST,
166 content: Some(content.clone())
167 });
168 self.uniform_buffer = Some(uniform_handle);
169 self.last_uniform = Some(content);
170 }
171
172 // Build the material
173 builder.add_buffer_from_id(Some(self.uniform_buffer.as_ref().unwrap().id()));
174 if let Some(albedo_t) = &self.albedo_t {
175 builder.add_texture_view_from_id(Some(albedo_t.id()));
176 builder.add_texture_sampler_from_id(Some(albedo_t.id()));
177 } else {
178 builder.add_texture_view_from_id(Some(placeholder_tex.0.id()));
179 builder.add_texture_sampler_from_id(Some(placeholder_tex.0.id()));
180 }
181 if let Some(metallic_roughness_t) = &self.metallic_roughness_t {
182 builder.add_texture_view_from_id(Some(metallic_roughness_t.id()));
183 builder.add_texture_sampler_from_id(Some(metallic_roughness_t.id()));
184 } else {
185 builder.add_texture_view_from_id(Some(placeholder_tex.0.id()));
186 builder.add_texture_sampler_from_id(Some(placeholder_tex.0.id()));
187 }
188 if let Some(normal_t) = &self.normal_t {
189 builder.add_texture_view_from_id(Some(normal_t.id()));
190 builder.add_texture_sampler_from_id(Some(normal_t.id()));
191 } else {
192 builder.add_texture_view_from_id(Some(placeholder_tex.0.id()));
193 builder.add_texture_sampler_from_id(Some(placeholder_tex.0.id()));
194 }
195 if let Some(occlusion_t) = &self.occlusion_t {
196 builder.add_texture_view_from_id(Some(occlusion_t.id()));
197 builder.add_texture_sampler_from_id(Some(occlusion_t.id()));
198 } else {
199 builder.add_texture_view_from_id(Some(placeholder_tex.0.id()));
200 builder.add_texture_sampler_from_id(Some(placeholder_tex.0.id()));
201 }
202 }
203
204 fn label(&self) -> &str {
205 &self.label
206 }
207}