Struct bevy::render::render_resource::std140::Sizer

pub struct Sizer { /* private fields */ }

Type that computes the buffer size needed by a series of std140 types laid out.

This type works well well when paired with Writer, precomputing a buffer’s size to alleviate the need to dynamically re-allocate buffers.

Example

struct Frob {
    vec3 size;
    float frobiness;
}

buffer FROBS {
    uint len;
    Frob[] frobs;
} frobs;

use bevy_crevice::std140::{self, AsStd140};

#[derive(AsStd140)]
struct Frob {
    size: mint::Vector3<f32>,
    frobiness: f32,
}

// Many APIs require that buffers contain at least enough space for all
// fixed-size bindiongs to a buffer as well as one element of any arrays, if
// there are any.
let mut sizer = std140::Sizer::new();
sizer.add::<u32>();
sizer.add::<Frob>();

let buffer = create_buffer_with_size(sizer.len());

Implementations

impl Sizer

pub fn new() -> Sizer

Create a new Sizer.

pub fn add<T>(&mut self) -> usize where
    T: AsStd140, 

Add a type’s necessary padding and size to the Sizer. Returns the offset into the buffer where that type would be written.

pub fn len(&self) -> usize

Returns the number of bytes required to contain all the types added to the Sizer.