1//! The shader that goes with `extended_material_bindless.rs`.
2//!
3//! This code demonstrates how to write shaders that are compatible with both
4//! bindless and non-bindless mode. See the `@if(BINDLESS)` blocks.
5
6import bevy_pbr::render::{
7    forward_io::{FragmentOutput, VertexOutput},
8    mesh_bindings::mesh,
9    pbr_fragment::pbr_input_from_standard_material,
10    pbr_functions::{apply_pbr_lighting, main_pass_post_lighting_processing},
11};
12import bevy_render::bindless::{bindless_samplers_filtering, bindless_textures_2d};
13
14@if(BINDLESS)
15import bevy_pbr::render::pbr_bindings::{material_array, material_indices};
16@else
17import bevy_pbr::render::pbr_bindings::material;
18
19/// Stores the indices of the bindless resources in the bindless resource arrays,
20/// for the `ExampleBindlessExtension` fields.
21struct ExampleBindlessExtendedMaterialIndices {
22    /// The index of the `ExampleBindlessExtendedMaterial` data in
23    /// `example_extended_material`.
24    material: u32,
25    /// The index of the texture we're going to modulate the base color with in
26    /// the `bindless_textures_2d` array.
27    modulate_texture: u32,
28    /// The index of the sampler we're going to sample the modulated texture with
29    /// in the `bindless_samplers_filtering` array.
30    modulate_texture_sampler: u32,
31}
32
33/// Plain data associated with this example material.
34struct ExampleBindlessExtendedMaterial {
35    /// The color that we multiply the base color, base color texture, and
36    /// modulated texture with.
37    modulate_color: vec4<f32>,
38}
39
40/// The indices of the bindless resources in the bindless resource arrays, for
41/// the `ExampleBindlessExtension` fields.
42@if(BINDLESS) {
43@group(constants::MATERIAL_BIND_GROUP) @binding(100) var<storage> example_extended_material_indices: array<ExampleBindlessExtendedMaterialIndices>;
44/// An array that holds the `ExampleBindlessExtendedMaterial` plain old data,
45/// indexed by `ExampleBindlessExtendedMaterialIndices.material`.
46@group(constants::MATERIAL_BIND_GROUP) @binding(101) var<storage> example_extended_material: array<ExampleBindlessExtendedMaterial>;
47}
48// In non-bindless mode, we simply use a uniform for the plain old data.
49@else {
50@group(constants::MATERIAL_BIND_GROUP) @binding(50) var<uniform> example_extended_material: ExampleBindlessExtendedMaterial;
51@group(constants::MATERIAL_BIND_GROUP) @binding(51) var modulate_texture: texture_2d<f32>;
52@group(constants::MATERIAL_BIND_GROUP) @binding(52) var modulate_sampler: sampler;
53}
54
55@fragment
56fn fragment(
57    in: VertexOutput,
58    @builtin(front_facing) is_front: bool,
59) -> FragmentOutput {
60    // Fetch the material slot. We'll use this in turn to fetch the bindless
61    // indices from `example_extended_material_indices`.
62    @if(BINDLESS)
63    let slot = mesh[in.instance_index].material_and_lightmap_bind_group_slot & 0xffffu;
64
65    // Generate a `PbrInput` struct from the `StandardMaterial` bindings.
66    var pbr_input = pbr_input_from_standard_material(in, is_front);
67
68    // Calculate the UV for the texture we're about to sample.
69    @if(BINDLESS)
70    let uv_transform = material_array[material_indices[slot].material].uv_transform;
71    @else
72    let uv_transform = material.uv_transform;
73    let uv = (uv_transform * vec3(in.uv, 1.0)).xy;
74
75    // Multiply the base color by the `modulate_texture` and `modulate_color`.
76    // Notice how we fetch the texture, sampler, and plain extended material
77    // data from the appropriate arrays.
78    @if(BINDLESS)
79    pbr_input.material.base_color *= textureSample(
80        bindless_textures_2d[example_extended_material_indices[slot].modulate_texture],
81        bindless_samplers_filtering[
82            example_extended_material_indices[slot].modulate_texture_sampler
83        ],
84        uv
85    ) * example_extended_material[example_extended_material_indices[slot].material].modulate_color;
86    @else
87    pbr_input.material.base_color *= textureSample(modulate_texture, modulate_sampler, uv) *
88        example_extended_material.modulate_color;
89
90    var out: FragmentOutput;
91    // Apply lighting.
92    out.color = apply_pbr_lighting(pbr_input);
93    // Apply in-shader post processing (fog, alpha-premultiply, and also
94    // tonemapping, debanding if the camera is non-HDR). Note this does not
95    // include fullscreen postprocessing effects like bloom.
96    out.color = main_pass_post_lighting_processing(pbr_input, out.color);
97    return out;
98}