move the dimensioned indexing out of spirv_backend and into coremem_types

this allows us to use it from the CPU implementation.

crates/spirv_backend/src/support.rs

@@ -1,8 +1,9 @@
 use core::ops::{Index, IndexMut};
 
-use spirv_std::RuntimeArray;
+// TODO: remove this re-export
+pub use coremem_types::dim::DimensionedSlice;
 
-use coremem_types::vec::Vec3u;
+use spirv_std::RuntimeArray;
 
 pub struct SizedArray<T> {
     items: T,
@@ -45,62 +46,3 @@ impl<'a, T> IndexMut<usize> for SizedArray<&'a mut RuntimeArray<T>> {
     }
 }
 
-pub struct DimensionedSlice<T> {
-    dim: Vec3u,
-    items: T,
-}
-
-impl<T> DimensionedSlice<T> {
-    pub fn new(dim: Vec3u, items: T) -> Self {
-        Self { dim, items }
-    }
-}
-
-impl<'a, T: Index<usize> + ?Sized> Index<Vec3u> for DimensionedSlice<&'a T> {
-    type Output=T::Output;
-
-    fn index(&self, idx: Vec3u) -> &Self::Output {
-        let idx = index(idx, self.dim);
-        &self.items[idx]
-    }
-}
-
-impl<'a, T: Index<usize> + ?Sized> Index<Vec3u> for DimensionedSlice<&'a mut T> {
-    type Output=T::Output;
-
-    fn index(&self, idx: Vec3u) -> &Self::Output {
-        let idx = index(idx, self.dim);
-        &self.items[idx]
-    }
-}
-
-impl<'a, T: IndexMut<usize> + ?Sized> IndexMut<Vec3u> for DimensionedSlice<&'a mut T> {
-    fn index_mut(&mut self, idx: Vec3u) -> &mut Self::Output {
-        let idx = index(idx, self.dim);
-        &mut self.items[idx]
-    }
-}
-
-fn index(loc: Vec3u, dim: Vec3u) -> usize {
-    ((loc.z()*dim.y() + loc.y())*dim.x() + loc.x()) as usize
-}
-
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    #[test]
-    fn test_index() {
-        let dim = Vec3u::new(2, 3, 7);
-        assert_eq!(index(Vec3u::new(0, 0, 0), dim), 0);
-        assert_eq!(index(Vec3u::new(1, 0, 0), dim), 1);
-        assert_eq!(index(Vec3u::new(0, 1, 0), dim), 2);
-        assert_eq!(index(Vec3u::new(1, 1, 0), dim), 3);
-        assert_eq!(index(Vec3u::new(0, 2, 0), dim), 4);
-        assert_eq!(index(Vec3u::new(0, 0, 1), dim), 6);
-        assert_eq!(index(Vec3u::new(1, 0, 1), dim), 7);
-        assert_eq!(index(Vec3u::new(0, 1, 1), dim), 8);
-        assert_eq!(index(Vec3u::new(1, 2, 1), dim), 11);
-        assert_eq!(index(Vec3u::new(1, 2, 2), dim), 17);
-    }
-}