1import package::{
2    render::{
3        pbr_prepass_functions,
4        pbr_bindings,
5        pbr_bindings::material,
6        pbr_types,
7        pbr_functions,
8        pbr_functions::SampleBias,
9        mesh_bindings::mesh,
10        mesh_view_bindings::view,
11    },
12    prepass::io as prepass_io,
13};
14
15import bevy_render::bindless::{bindless_samplers_filtering, bindless_textures_2d};
16
17@if(MESHLET_MESH_MATERIAL_PASS)
18import package::meshlet::visibility_buffer_resolve::resolve_vertex_output;
19
20@if(BINDLESS)
21import package::render::pbr_bindings::material_indices;
22
23@if(PREPASS_FRAGMENT)
24@fragment
25fn fragment(
26@if(MESHLET_MESH_MATERIAL_PASS)
27    @builtin(position) frag_coord: vec4<f32>,
28@if(!MESHLET_MESH_MATERIAL_PASS)
29    in: prepass_io::VertexOutput,
30@if(!MESHLET_MESH_MATERIAL_PASS)
31    @builtin(front_facing) is_front: bool,
32) -> prepass_io::FragmentOutput {
33@if(MESHLET_MESH_MATERIAL_PASS)
34    let in = resolve_vertex_output(frag_coord);
35@if(MESHLET_MESH_MATERIAL_PASS)
36    let is_front = true;
37
38@if(!MESHLET_MESH_MATERIAL_PASS && BINDLESS)
39    let slot = mesh[in.instance_index].material_and_lightmap_bind_group_slot & 0xffffu;
40@if(!MESHLET_MESH_MATERIAL_PASS && BINDLESS)
41    let flags = pbr_bindings::material_array[material_indices[slot].material].flags;
42@if(!MESHLET_MESH_MATERIAL_PASS && BINDLESS)
43    let uv_transform = pbr_bindings::material_array[material_indices[slot].material].uv_transform;
44@if(!MESHLET_MESH_MATERIAL_PASS && !BINDLESS)
45    let flags = pbr_bindings::material.flags;
46@if(!MESHLET_MESH_MATERIAL_PASS && !BINDLESS)
47    let uv_transform = pbr_bindings::material.uv_transform;
48
49    // If we're in the crossfade section of a visibility range, conditionally
50    // discard the fragment according to the visibility pattern.
51@if(!MESHLET_MESH_MATERIAL_PASS && VISIBILITY_RANGE_DITHER)
52    pbr_functions::visibility_range_dither(in.position, in.visibility_range_dither);
53
54@if(!MESHLET_MESH_MATERIAL_PASS)
55    pbr_prepass_functions::prepass_sample_color_and_alpha_discard(in);
56
57    var out: prepass_io::FragmentOutput;
58
59@if(UNCLIPPED_DEPTH_ORTHO_EMULATION)
60    out.frag_depth = in.unclipped_depth;
61
62    // NOTE: Unlit bit not set means == 0 is true, so the true case is if lit
63@if(NORMAL_PREPASS)
64    if (flags & pbr_types::STANDARD_MATERIAL_FLAGS_UNLIT_BIT) == 0u {
65        let double_sided = (flags & pbr_types::STANDARD_MATERIAL_FLAGS_DOUBLE_SIDED_BIT) != 0u;
66@if(MESHLET_MESH_MATERIAL_PASS)
67        let mesh_flags = in.mesh_flags;
68@else
69        let mesh_flags = mesh[in.instance_index].flags;
70        let is_logically_front = pbr_functions::winding_corrected_front_facing(mesh_flags, is_front);
71
72        let world_normal = pbr_functions::prepare_world_normal(
73            in.world_normal,
74            double_sided,
75            is_logically_front,
76        );
77
78        var normal = world_normal;
79
80@if(VERTEX_UVS) {
81@if(VERTEX_TANGENTS) {
82@if(STANDARD_MATERIAL_NORMAL_MAP) {
83
84// TODO: Transforming UVs mean we need to apply derivative chain rule for meshlet mesh material pass
85@if(STANDARD_MATERIAL_NORMAL_MAP_UV_B)
86        let uv = (uv_transform * vec3(in.uv_b, 1.0)).xy;
87@else
88        let uv = (uv_transform * vec3(in.uv, 1.0)).xy;
89
90        // Fill in the sample bias so we can sample from textures.
91        var bias: SampleBias;
92@if(MESHLET_MESH_MATERIAL_PASS) {
93        // Apply mip bias by scaling the gradients used by textureSampleGrad.
94        let mip_scale = exp2(view.mip_bias);
95        bias.ddx_uv = in.ddx_uv * mip_scale;
96        bias.ddy_uv = in.ddy_uv * mip_scale;
97}
98@if(!MESHLET_MESH_MATERIAL_PASS)
99        bias.mip_bias = view.mip_bias;
100
101@if(BINDLESS)
102        let texture = bindless_textures_2d[material_indices[slot].normal_map_texture];
103@else
104        let texture = pbr_bindings::normal_map_texture;
105@if(BINDLESS)
106        let sampler_ = bindless_samplers_filtering[material_indices[slot].normal_map_sampler];
107@else
108        let sampler_ = pbr_bindings::normal_map_sampler;
109@if(MESHLET_MESH_MATERIAL_PASS)
110        let Nt =
111            textureSampleGrad(
112                texture,
113                sampler_,
114                uv,
115                bias.ddx_uv,
116                bias.ddy_uv,
117            ).rgb;
118@if(!MESHLET_MESH_MATERIAL_PASS)
119        let Nt =
120            textureSampleBias(
121                texture,
122                sampler_,
123                uv,
124                bias.mip_bias,
125            ).rgb;
126        let TBN = pbr_functions::calculate_tbn_mikktspace(normal, in.world_tangent);
127
128        normal = pbr_functions::apply_normal_mapping(
129            flags,
130            TBN,
131            double_sided,
132            is_logically_front,
133            Nt,
134        );
135
136}
137}
138}
139
140        out.normal = vec4(normal * 0.5 + vec3(0.5), 1.0);
141    } else {
142        out.normal = vec4(in.world_normal * 0.5 + vec3(0.5), 1.0);
143    }
144
145@if(MOTION_VECTOR_PREPASS && MESHLET_MESH_MATERIAL_PASS)
146    out.motion_vector = in.motion_vector;
147@if(MOTION_VECTOR_PREPASS && !MESHLET_MESH_MATERIAL_PASS)
148    out.motion_vector = pbr_prepass_functions::calculate_motion_vector(in.world_position, in.previous_world_position);
149
150    return out;
151}
152@else
153@fragment
154fn fragment(in: prepass_io::VertexOutput) {
155    pbr_prepass_functions::prepass_sample_color_and_alpha_discard(in);
156}