1#import bevy_pbr::{
2    pbr_types,
3    pbr_functions::alpha_discard,
4    pbr_fragment::pbr_input_from_standard_material,
5    decal::clustered::apply_decal_base_color,
6}
7
8#ifdef PREPASS_PIPELINE
9#import bevy_pbr::{
10    prepass_io::{VertexOutput, FragmentOutput},
11    pbr_deferred_functions::deferred_output,
12}
13#else
14#import bevy_pbr::{
15    forward_io::{VertexOutput, FragmentOutput},
16    pbr_functions,
17    pbr_functions::{apply_pbr_lighting, main_pass_post_lighting_processing},
18    pbr_types::STANDARD_MATERIAL_FLAGS_UNLIT_BIT,
19}
20#endif
21
22#ifdef MESHLET_MESH_MATERIAL_PASS
23#import bevy_pbr::meshlet_visibility_buffer_resolve::resolve_vertex_output
24#endif
25
26#ifdef OIT_ENABLED
27#import bevy_core_pipeline::oit::oit_draw
28#endif // OIT_ENABLED
29
30#ifdef FORWARD_DECAL
31#import bevy_pbr::decal::forward::get_forward_decal_info
32#endif
33
34@fragment
35fn fragment(
36#ifdef MESHLET_MESH_MATERIAL_PASS
37    @builtin(position) frag_coord: vec4<f32>,
38#else
39    vertex_output: VertexOutput,
40    @builtin(front_facing) is_front: bool,
41#endif
42) -> FragmentOutput {
43#ifdef MESHLET_MESH_MATERIAL_PASS
44    let vertex_output = resolve_vertex_output(frag_coord);
45    let is_front = true;
46#endif
47
48    var in = vertex_output;
49
50    // If we're in the crossfade section of a visibility range, conditionally
51    // discard the fragment according to the visibility pattern.
52#ifdef VISIBILITY_RANGE_DITHER
53    pbr_functions::visibility_range_dither(in.position, in.visibility_range_dither);
54#endif
55
56#ifdef FORWARD_DECAL
57    let forward_decal_info = get_forward_decal_info(in);
58    in.world_position = forward_decal_info.world_position;
59    in.uv = forward_decal_info.uv;
60#endif
61
62    // generate a PbrInput struct from the StandardMaterial bindings
63    var pbr_input = pbr_input_from_standard_material(in, is_front);
64
65    // alpha discard
66    pbr_input.material.base_color = alpha_discard(pbr_input.material, pbr_input.material.base_color);
67
68    // clustered decals
69    pbr_input.material.base_color = apply_decal_base_color(
70        in.world_position.xyz,
71        in.position.xy,
72        pbr_input.material.base_color
73    );
74
75#ifdef PREPASS_PIPELINE
76    // write the gbuffer, lighting pass id, and optionally normal and motion_vector textures
77    let out = deferred_output(in, pbr_input);
78#else
79    // in forward mode, we calculate the lit color immediately, and then apply some post-lighting effects here.
80    // in deferred mode the lit color and these effects will be calculated in the deferred lighting shader
81    var out: FragmentOutput;
82    if (pbr_input.material.flags & STANDARD_MATERIAL_FLAGS_UNLIT_BIT) == 0u {
83        out.color = apply_pbr_lighting(pbr_input);
84    } else {
85        out.color = pbr_input.material.base_color;
86    }
87
88    // apply in-shader post processing (fog, alpha-premultiply, and also tonemapping, debanding if the camera is non-hdr)
89    // note this does not include fullscreen postprocessing effects like bloom.
90    out.color = main_pass_post_lighting_processing(pbr_input, out.color);
91#endif
92
93#ifdef OIT_ENABLED
94    let alpha_mode = pbr_input.material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_RESERVED_BITS;
95    if alpha_mode != pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_OPAQUE {
96        // The fragments will only be drawn during the oit resolve pass.
97        oit_draw(in.position, out.color);
98        discard;
99    }
100#endif // OIT_ENABLED
101
102#ifdef FORWARD_DECAL
103        out.color.a = min(forward_decal_info.alpha, out.color.a);
104#endif
105
106        return out;
107}