From e3bfe4270c63e7fa09a6440e9238b79d18a793f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jakub=20Hlusi=C4=8Dka?= <Limeth@users.noreply.github.com>
Date: Sun, 16 Sep 2018 23:44:36 +0200
Subject: [PATCH] Add a `reinterpret` function to `BufferSlice` (#1038)

Add a `reinterpret` function to `BufferSlice`
---
 CHANGELOG.md                |  3 ++-
 vulkano/src/buffer/slice.rs | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1b4d9745..69663c6d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,8 +1,9 @@
 # Unreleased (Breaking)
 
-- Split 'PersistentDescriptorSetError::MissingUsage' into 'MissingImageUsage' and 'MissingBufferUsage'
+- Split `PersistentDescriptorSetError::MissingUsage` into `MissingImageUsage` and `MissingBufferUsage`
   each with a matching enum indicating the usage that was missing.
 - Fix instance_count when using draw_index with instance buffers
+- Added a `reinterpret` function to `BufferSlice`
 
 # Version 0.10.0 (2018-08-10)
 
diff --git a/vulkano/src/buffer/slice.rs b/vulkano/src/buffer/slice.rs
index fa4cb4d4..4d8983a4 100644
--- a/vulkano/src/buffer/slice.rs
+++ b/vulkano/src/buffer/slice.rs
@@ -132,6 +132,38 @@ impl<T: ?Sized, B> BufferSlice<T, B> {
             size: size,
         }
     }
+
+    /// Changes the `T` generic parameter of the `BufferSlice` to the desired type. This can be
+    /// useful when you have a buffer with various types of data and want to create a typed slice
+    /// of a region that contains a single type of data.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use std::sync::Arc;
+    /// # use vulkano::buffer::BufferSlice;
+    /// # use vulkano::buffer::immutable::ImmutableBuffer;
+    /// # struct VertexImpl;
+    /// let blob_slice: BufferSlice<[u8], Arc<ImmutableBuffer<[u8]>>> = return;
+    /// let vertex_slice: BufferSlice<[VertexImpl], Arc<ImmutableBuffer<[u8]>>> = unsafe {
+    ///     blob_slice.reinterpret::<[VertexImpl]>()
+    /// };
+    /// ```
+    ///
+    /// # Safety
+    ///
+    /// Correct `offset` and `size` must be ensured before using this `BufferSlice` on the device.
+    /// See `BufferSlice::slice` for adjusting these properties.
+    #[inline]
+    pub unsafe fn reinterpret<R: ?Sized>(self) -> BufferSlice<R, B>
+    {
+        BufferSlice {
+            marker: PhantomData,
+            resource: self.resource,
+            offset: self.offset,
+            size: self.size,
+        }
+    }
 }
 
 impl<T, B> BufferSlice<[T], B> {