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 `#ifdef BINDLESS` blocks.
5
6#import bevy_pbr::{
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}
12#import bevy_render::bindless::{bindless_samplers_filtering, bindless_textures_2d}
13
14#ifdef BINDLESS
15#import bevy_pbr::pbr_bindings::{material_array, material_indices}
16#else   // BINDLESS
17#import bevy_pbr::pbr_bindings::material
18#endif  // BINDLESS
19
20// Stores the indices of the bindless resources in the bindless resource arrays,
21// for the `ExampleBindlessExtension` fields.
22struct ExampleBindlessExtendedMaterialIndices {
23    // The index of the `ExampleBindlessExtendedMaterial` data in
24    // `example_extended_material`.
25    material: u32,
26    // The index of the texture we're going to modulate the base color with in
27    // the `bindless_textures_2d` array.
28    modulate_texture: u32,
29    // The index of the sampler we're going to sample the modulated texture with
30    // in the `bindless_samplers_filtering` array.
31    modulate_texture_sampler: u32,
32}
33
34// Plain data associated with this example material.
35struct ExampleBindlessExtendedMaterial {
36    // The color that we multiply the base color, base color texture, and
37    // modulated texture with.
38    modulate_color: vec4<f32>,
39}
40
41#ifdef BINDLESS
42
43// The indices of the bindless resources in the bindless resource arrays, for
44// the `ExampleBindlessExtension` fields.
45@group(2) @binding(100) var<storage> example_extended_material_indices:
46    array<ExampleBindlessExtendedMaterialIndices>;
47// An array that holds the `ExampleBindlessExtendedMaterial` plain old data,
48// indexed by `ExampleBindlessExtendedMaterialIndices.material`.
49@group(2) @binding(101) var<storage> example_extended_material:
50    array<ExampleBindlessExtendedMaterial>;
51
52#else   // BINDLESS
53
54// In non-bindless mode, we simply use a uniform for the plain old data.
55@group(2) @binding(50) var<uniform> example_extended_material: ExampleBindlessExtendedMaterial;
56@group(2) @binding(51) var modulate_texture: texture_2d<f32>;
57@group(2) @binding(52) var modulate_sampler: sampler;
58
59#endif  // BINDLESS
60
61@fragment
62fn fragment(
63    in: VertexOutput,
64    @builtin(front_facing) is_front: bool,
65) -> FragmentOutput {
66#ifdef BINDLESS
67    // Fetch the material slot. We'll use this in turn to fetch the bindless
68    // indices from `example_extended_material_indices`.
69    let slot = mesh[in.instance_index].material_and_lightmap_bind_group_slot & 0xffffu;
70#endif  // BINDLESS
71
72    // Generate a `PbrInput` struct from the `StandardMaterial` bindings.
73    var pbr_input = pbr_input_from_standard_material(in, is_front);
74
75    // Calculate the UV for the texture we're about to sample.
76#ifdef BINDLESS
77    let uv_transform = material_array[material_indices[slot].material].uv_transform;
78#else   // BINDLESS
79    let uv_transform = material.uv_transform;
80#endif  // BINDLESS
81    let uv = (uv_transform * vec3(in.uv, 1.0)).xy;
82
83    // Multiply the base color by the `modulate_texture` and `modulate_color`.
84#ifdef BINDLESS
85    // Notice how we fetch the texture, sampler, and plain extended material
86    // data from the appropriate arrays.
87    pbr_input.material.base_color *= textureSample(
88        bindless_textures_2d[example_extended_material_indices[slot].modulate_texture],
89        bindless_samplers_filtering[
90            example_extended_material_indices[slot].modulate_texture_sampler
91        ],
92        uv
93    ) * example_extended_material[example_extended_material_indices[slot].material].modulate_color;
94#else   // BINDLESS
95    pbr_input.material.base_color *= textureSample(modulate_texture, modulate_sampler, uv) *
96        example_extended_material.modulate_color;
97#endif  // BINDLESS
98
99    var out: FragmentOutput;
100    // Apply lighting.
101    out.color = apply_pbr_lighting(pbr_input);
102    // Apply in-shader post processing (fog, alpha-premultiply, and also
103    // tonemapping, debanding if the camera is non-HDR). Note this does not
104    // include fullscreen postprocessing effects like bloom.
105    out.color = main_pass_post_lighting_processing(pbr_input, out.color);
106    return out;
107}