1import package::mesh2d::{
2    vertex_output::VertexOutput,
3    view_bindings::view,
4    bindings::mesh,
5};
6import bevy_render::bindless::{bindless_samplers_filtering, bindless_textures_2d};
7
8@if(TONEMAP_IN_SHADER)
9import bevy_core_pipeline::tonemapping;
10@if(SRGB_OUTPUT)
11import bevy_render::color_operations::linear_to_srgb;
12@if(OKLAB_OUTPUT)
13import bevy_render::color_operations::linear_rgb_to_oklab;
14
15struct ColorMaterial {
16    color: vec4<f32>,
17    uv_transform: mat3x3<f32>,
18    /// 'flags' is a bit field indicating various options. u32 is 32 bits so we have up to 32 options.
19    flags: u32,
20    alpha_cutoff: f32,
21};
22
23@if(BINDLESS) {
24/// The index table for bindless operation.
25struct ColorMaterialBindings {
26    material: u32,          // 0
27    color_texture: u32,     // 1
28    color_sampler: u32,     // 2
29}
30
31@group(constants::MATERIAL_BIND_GROUP) @binding(0) var<storage> color_material_indices:
32    array<ColorMaterialBindings>;
33@group(constants::MATERIAL_BIND_GROUP) @binding(10) var<storage> color_materials: array<ColorMaterial>;
34}
35@else {
36@group(constants::MATERIAL_BIND_GROUP) @binding(0) var<uniform> material: ColorMaterial;
37@group(constants::MATERIAL_BIND_GROUP) @binding(1) var texture: texture_2d<f32>;
38@group(constants::MATERIAL_BIND_GROUP) @binding(2) var texture_sampler: sampler;
39}
40
41const COLOR_MATERIAL_FLAGS_TEXTURE_BIT: u32              = 1u;
42const COLOR_MATERIAL_FLAGS_ALPHA_MODE_RESERVED_BITS: u32 = 3221225472u; // (0b11u32 << 30)
43const COLOR_MATERIAL_FLAGS_ALPHA_MODE_OPAQUE: u32        = 0u;          // (0u32 << 30)
44const COLOR_MATERIAL_FLAGS_ALPHA_MODE_MASK: u32          = 1073741824u; // (1u32 << 30)
45const COLOR_MATERIAL_FLAGS_ALPHA_MODE_BLEND: u32         = 2147483648u; // (2u32 << 30)
46
47@fragment
48fn fragment(
49    in: VertexOutput,
50) -> @location(0) vec4<f32> {
51    let slot = mesh[in.instance_index].material_bind_group_slot;
52
53@if(BINDLESS)
54    var output_color: vec4<f32> = color_materials[color_material_indices[slot].material].color;
55@else
56    var output_color: vec4<f32> = material.color;
57
58@if(VERTEX_COLORS)
59    output_color = output_color * in.color;
60
61@if(BINDLESS)
62    let uv_transform = color_materials[color_material_indices[slot].material].uv_transform;
63@else
64    let uv_transform = material.uv_transform;
65@if(BINDLESS)
66    let flags = color_materials[color_material_indices[slot].material].flags;
67@else
68    let flags = material.flags;
69@if(BINDLESS)
70    let alpha_cutoff = color_materials[color_material_indices[slot].material].alpha_cutoff;
71@else
72    let alpha_cutoff = material.alpha_cutoff;
73
74    let uv = (uv_transform * vec3(in.uv, 1.0)).xy;
75
76    if ((flags & COLOR_MATERIAL_FLAGS_TEXTURE_BIT) != 0u) {
77        @if(BINDLESS)
78        output_color = output_color * textureSample(
79            bindless_textures_2d[color_material_indices[slot].color_texture],
80            bindless_samplers_filtering[color_material_indices[slot].color_sampler],
81            uv
82        );
83        @else
84        output_color = output_color * textureSample(texture, texture_sampler, uv);
85    }
86
87    output_color = alpha_discard(flags, alpha_cutoff, output_color);
88
89@if(TONEMAP_IN_SHADER)
90    output_color = tonemapping::tone_mapping(output_color, view.color_grading);
91@if(SRGB_OUTPUT)
92    output_color = vec4(linear_to_srgb(output_color.rgb), output_color.a);
93@if(OKLAB_OUTPUT)
94    output_color = vec4(linear_rgb_to_oklab(output_color.rgb), output_color.a);
95    return output_color;
96}
97
98fn alpha_discard(flags: u32, alpha_cutoff: f32, output_color: vec4<f32>) -> vec4<f32> {
99    var color = output_color;
100    let alpha_mode = flags & COLOR_MATERIAL_FLAGS_ALPHA_MODE_RESERVED_BITS;
101    if alpha_mode == COLOR_MATERIAL_FLAGS_ALPHA_MODE_OPAQUE {
102        // NOTE: If rendering as opaque, alpha should be ignored so set to 1.0
103        color.a = 1.0;
104    }
105    else {
106        @if(MAY_DISCARD)
107        if alpha_mode == COLOR_MATERIAL_FLAGS_ALPHA_MODE_MASK {
108           if color.a >= alpha_cutoff {
109                // NOTE: If rendering as masked alpha and >= the cutoff, render as fully opaque
110                color.a = 1.0;
111            } else {
112                // NOTE: output_color.a < in.material.alpha_cutoff should not be rendered
113                discard;
114            }
115        }
116    }
117
118    return color;
119}