Macro pipeline

macro_rules! pipeline {
    { @len } => { ... };
    { @len $last:tt } => { ... };
    { @len $first:tt $( $rest:tt )+ } => { ... };
    { @texturefmt $var:ident , SURFACE } => { ... };
    { @texturefmt $var:ident , $fragmentfmt:ident } => { ... };
    { $struct:ident =>
        bind_groups : [
            $( $bindgroupnum:tt => $bindgroup:ty ),* $(,)?
        ],
        vertex_types: [
            $( $vertexnum:tt => $vertexty:ty ),* $(,)?
        ],
        fragment_targets: [
            $( $fragmentnum:tt => $blend:ident $mask:ident as $fragmentfmt:ident ),* $(,)?
        ],
        push_constants: [
            $( $pushfrom:literal .. $pushto:literal @ $pushshaderstage:ident ),* $(,)?
        ],
        depth: $depthfmt:expr,
        cull: $cull:expr,
    } => { ... };
}

Define a pipeline, with internal bind group types.

You need to number each field and include the total count of bind groups, it’s just a limitation of macros.

pipeline! { ThingPipeline {
    bind_groups: [
        0 StuffBindGroup,
        1 CameraBindGroup,
        2 TextureBindGroup,
    ],
} }

let thing_pipeline = StuffBindGroup::new(...);
queue.write_buffer(&stuff_bind_group.something_else_buffer, 0, &[1, 2, 3, ..]);