1//! Example of a fragment shader for an ExtendedMaterial<StandardMaterial, E> setup to
2//! correctly handle order independent transparency.
3//! See examples/3d/order_independent_transpatency.rs
4
5// In our case we're always transparent and so forward rendered, but
6// this is the general setup if it's not always the case.
7@if(PREPASS_PIPELINE)
8import bevy_pbr::{
9    prepass::io::{VertexOutput, FragmentOutput},
10};
11@else // PREPASS_PIPELINE
12import bevy_pbr::render::{
13    forward_io::{VertexOutput, FragmentOutput},
14};
15
16@if(MATERIAL_OIT_ENABLED)
17import bevy_core_pipeline::oit::draw::oit_draw;
18@if(MATERIAL_OIT_ENABLED)
19import bevy_pbr::render::pbr_types;
20@if(MATERIAL_OIT_ENABLED)
21import bevy_pbr::render::pbr_fragment::pbr_input_from_standard_material;
22
23/// The material parameters
24struct Colors {
25    color1: vec4<f32>,
26    color2: vec4<f32>,
27};
28
29@group(constants::MATERIAL_BIND_GROUP) @binding(100) var<uniform> material: Colors;
30
31@fragment
32fn fragment(
33    in: VertexOutput,
34) -> FragmentOutput {
35    var out: FragmentOutput;
36
37    // This produces a checkered pattern along the uv isolines filled with the two colors
38    let grid = vec2u(in.uv * 30.0f) % 2;
39    out.color = select(material.color1, material.color2, (grid.x + grid.y == 1));
40
41@if(MATERIAL_OIT_ENABLED) {
42    let pbr_input = pbr_input_from_standard_material(in, false);
43    let alpha_mode = pbr_input.material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_RESERVED_BITS;
44    if alpha_mode == pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_BLEND {
45        // The fragments will only be drawn during the oit resolve pass.
46        oit_draw(in.position, vec4(out.color.rgb * out.color.a, out.color.a));
47        discard;
48    }
49    // Both `Premultiplied` and `Add` colors are premultiplied in `premultiply_alpha()`
50    if alpha_mode == pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_PREMULTIPLIED
51        || alpha_mode == pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_ADD {
52        // The fragments will only be drawn during the oit resolve pass.
53        oit_draw(in.position, out.color);
54        discard;
55    }
56}
57
58    return out;
59}