spirv_backend/support.rs: remove the re-export of DimensionedSlice

also add some docs

crates/spirv_backend/src/adapt.rs

@@ -1,12 +1,12 @@
 use spirv_std::RuntimeArray;
 
-use coremem_types::step::{StepEContext, StepHContext, VolumeSampleNeg, VolumeSamplePos};
+use coremem_types::dim::DimensionedSlice;
 use coremem_types::mat::Material;
 use coremem_types::real::Real;
-use coremem_types::step::SimMeta;
+use coremem_types::step::{SimMeta, StepEContext, StepHContext, VolumeSampleNeg, VolumeSamplePos};
 use coremem_types::vec::{Vec3, Vec3u};
 
-use crate::support::{DimensionedSlice, SizedArray};
+use crate::support::SizedArray;
 
 pub(crate) fn step_h<R: Real, M: Material<R>>(
     idx: Vec3u,

crates/spirv_backend/src/support.rs

@@ -1,16 +1,19 @@
 use core::ops::{Index, IndexMut};
 
-// TODO: remove this re-export
-pub use coremem_types::dim::DimensionedSlice;
-
 use spirv_std::RuntimeArray;
 
+/// this is intended to wrap an unsized array with a length and provide safe indexing operations
+/// into it. it behaves quite similar to a native rust slice, and ideally we'd just use that but
+/// spirv support for slices is poor.
 pub struct SizedArray<T> {
     items: T,
     len: usize,
 }
 
 impl<T> SizedArray<T> {
+    /// construct the slice from some other collection and the number of items in said collection.
+    /// safety: caller must validate that it's safe to index all `len` elements in the underlying
+    /// collection.
     pub unsafe fn new(items: T, len: usize) -> Self {
         Self { items, len }
     }