Struct web_glitz::pipeline::graphics::IndexBuffer

pub struct IndexBuffer<T> { /* fields omitted */ }

A GPU-accessible memory buffer that contains an indexed list for indexed drawing.

Very similar to a [Buffer] but exclusively for data used for indexed drawing. For security reasons, WebGL implementations require that index buffer never reference out of bounds vertices. To ensure this, the browser will perform additional checks on the indices in index buffers. To ensure that these checks needs only be done for index buffers (and not all buffers), a dichotomy was introduced that treats index buffers differently from buffers intended for different uses (e.g. a vertex data buffer, a uniform buffer, or a transform feedback buffer), where an index buffers may only ever be bound as an index buffer, never as a different kind of buffer, whereas other buffer kinds may be used for multiple ends. Additionally, index buffers are not allowed to perform GPU copy commands; only upload commands are permitted, where after each upload the browser will have to reevaluate the range of indices contained in the buffer (or buffer sub-region) when it is next used to draw. In short, for index data use an IndexBuffer; for all other ends use an ordinary [Buffer].

Example

use web_glitz::pipeline::graphics::IndexBuffer;
use web_glitz::buffer::UsageHint;

let index_buffer: IndexBuffer<u16> = context.create_index_buffer([1, 2, 3, 4], UsageHint::StreamDraw);

Implementations

impl<T> IndexBuffer<T>

pub fn usage_hint(&self) -> UsageHint

Returns the UsageHint that was specified for this IndexBuffer when it was created.

See UsageHint for details.

pub fn len(&self) -> usize

Returns the number of indices contained in this IndexBuffer.

pub fn get<R>(&self, range: R) -> Option<IndexBufferView<'_, T>> where
    R: IndexBufferSliceRange<T>, 

Returns an IndexBufferView on a slice of the indices this IndexBuffer based on the given range or None if the range is out of bounds

Examples

use web_glitz::pipeline::graphics::IndexBuffer;
use web_glitz::buffer::UsageHint;

let index_buffer: IndexBuffer<u16> = context.create_index_buffer([1, 2, 3, 4], UsageHint::StreamDraw);

index_buffer.get(1..3); // Some IndexBufferView<[f32]> containing `[2.0, 3.0]`
index_buffer.get(..2); // Some IndexBufferView<[f32]> containing `[1.0 2.0]`

pub unsafe fn get_unchecked<R>(&self, index: R) -> IndexBufferView<'_, T> where
    R: IndexBufferSliceRange<T>, 

Returns an IndexBufferView on a slice of the indices this IndexBuffer based on the given range, without performing any bounds checks

Examples

use web_glitz::pipeline::graphics::IndexBuffer;
use web_glitz::buffer::UsageHint;

let index_buffer: IndexBuffer<u16> = context.create_index_buffer([1, 2, 3, 4], UsageHint::StreamDraw);

unsafe { index_buffer.get_unchecked(1..3) }; // IndexBufferView<[f32]> containing `[2.0, 3.0]`

Unsafe

Only safe if range is in bounds. See [get] for a safe alternative.

impl<T> IndexBuffer<T> where
    T: IndexFormat, 

pub fn upload_command<D>(&self, index_data: D) -> IndexBufferUploadCommand<T, D> where
    D: Borrow<[T]> + Send + Sync + 'static, 

Returns a command which, when executed will replace the indices contained in this IndexBuffer with the indices in given index_data.

If the index_data contains fewer elements than this IndexBuffer, then only the first N elements will be replaced, where N is the number of elements in the given index_data.

If the index_data contains more elements than this IndexBuffer, then only the first M elements in the index_data will be used to update this IndexBuffer, where M is the number of elements in the IndexBuffer.

impl<T> IndexBuffer<MaybeUninit<T>> where
    T: IndexFormat, 

pub fn upload_command<D>(
    &self,
    index_data: D
) -> IndexBufferUploadCommand<MaybeUninit<T>, D> where
    D: Borrow<[MaybeUninit<T>]> + Send + Sync + 'static, 

Returns a command which, when executed will replace the indices contained in this IndexBuffer with the indices in given index_data.

If the index_data contains fewer elements than this IndexBuffer, then only the first N elements will be replaced, where N is the number of elements in the given index_data.

If the index_data contains more elements than this IndexBuffer, then only the first M elements in the index_data will be used to update this IndexBuffer, where M is the number of elements in the IndexBuffer.

impl<T> IndexBuffer<MaybeUninit<T>> where
    T: IndexFormat, 

pub unsafe fn assume_init(self) -> IndexBuffer<T>

Converts to IndexBuffer<T>.

Safety

Any tasks that read from the buffer after assume_init was called, must only be executed after the buffer was initialized. Note that certain tasks may wait on GPU fences and allow a runtime to progress other tasks while its waiting on the fence. As such, submitting your initialization tasks as part of a task that includes fencing (these are typically tasks that include "download" commands), may not guarantee that the buffer was initialized before any tasks that are submitted later will begin executing.

Trait Implementations

impl<'a, T> From<&'a IndexBuffer<T>> for IndexBufferView<'a, T>

fn from(buffer: &'a IndexBuffer<T>) -> IndexBufferView<'a, T>

Performs the conversion.

impl<T> Hash for IndexBuffer<T>

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl<'a, T> IndexData for &'a IndexBuffer<T> where
    T: IndexFormat, 

fn descriptor(&self) -> IndexDataDescriptor

Returns a descriptor of the index data.

impl<T> PartialEq<IndexBuffer<T>> for IndexBuffer<T>

fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

#[must_use]fn ne(&self, other: &Rhs) -> bool

This method tests for !=.