Macro vertex_attr_array

macro_rules! vertex_attr_array {
    ($($location:expr => $format:ident),* $(,)?) => { ... };
}

Macro to produce an array of VertexAttribute.

The input is a sequence of pairs of shader locations (expression of type u32) and variant names of VertexFormat.

The return value has type [VertexAttribute; N], where N is the number of inputs.

Offsets are calculated automatically, using the assumption that there is no padding or other data between attributes.

Example

// Suppose that this is our vertex format:
#[repr(C, packed)]
struct Vertex {
    foo: [f32; 2],
    bar: f32,
    baz: [u16; 4],
}

// Then these attributes match it:
let attrs = wgpu::vertex_attr_array![
    0 => Float32x2,
    1 => Float32,
    2 => Uint16x4,
];

// Here's the full data structure the macro produced:
use wgpu::{VertexAttribute as A, VertexFormat as F};
assert_eq!(attrs, [
    A { format: F::Float32x2, offset:  0, shader_location: 0, },
    A { format: F::Float32,   offset:  8, shader_location: 1, },
    A { format: F::Uint16x4,  offset: 12, shader_location: 2, },
]);

See VertexBufferLayout for an example building on this one.