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//! Vertex and index buffers.
use std::mem;
use super::id;
/// Identifier for an index or vertex buffer.
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
pub struct BufferId(id::Id);
impl BufferId {
/// Get the next id.
pub(crate) fn next() -> Self {
Self(id::next())
}
}
/// Buffer source.
pub enum BufferSource<'a, T> {
/// A slice of data.
Slice(&'a [T]),
/// An empty pre-allocated buffer.
Empty {
/// Size in bytes of buffer.
size: usize,
},
}
impl<'a, T> BufferSource<'a, T> {
/// Empty buffer of `elements * size_of::<T>` bytes.
pub fn empty(elements: usize) -> BufferSource<'a, T> {
BufferSource::Empty {
size: elements * mem::size_of::<T>(),
}
}
/// Buffer from a slice of `T`.
pub fn slice(data: &'a [T]) -> BufferSource<'a, T> {
BufferSource::Slice(data)
}
}
/// Type of object the buffer holds.
#[derive(Clone, Copy, Debug, PartialEq)]
pub enum BufferKind {
Vertex,
Index,
}
/// How the buffer will be used.
#[derive(Clone, Copy, Debug, PartialEq)]
pub enum BufferUsage {
/// Buffer will never be updated.
Immutable,
/// Buffer will be updated occasionally.
Dynamic,
/// Buffer will be updated often.
Stream,
}