From f5c503a3aaeaa24062bc15af90e9b0f002bf6912 Mon Sep 17 00:00:00 2001
From: Jarrod Doyle <thejarroddoyle@gmail.com>
Date: Sat, 23 Mar 2024 10:55:54 +0000
Subject: [PATCH] Add buffer extension trait

---
 src/gfx/buffer.rs | 26 ++++++++++++++++++++++++++
 src/gfx/mod.rs    |  2 +-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/gfx/buffer.rs b/src/gfx/buffer.rs
index 1b4c73c..441f2e3 100644
--- a/src/gfx/buffer.rs
+++ b/src/gfx/buffer.rs
@@ -1,3 +1,5 @@
+use std::ops::RangeBounds;
+
 use bytemuck::NoUninit;
 use wgpu::util::DeviceExt;
 
@@ -71,3 +73,27 @@ impl<'a> BulkBufferBuilder<'a> {
         buffers
     }
 }
+
+pub trait BufferExt {
+    fn get_mapped_range<S: RangeBounds<wgpu::BufferAddress>, T: bytemuck::Pod>(
+        &self,
+        context: &Context,
+        bounds: S,
+    ) -> Vec<T>;
+}
+
+impl BufferExt for wgpu::Buffer {
+    fn get_mapped_range<S: RangeBounds<wgpu::BufferAddress>, T: bytemuck::Pod>(
+        &self,
+        context: &Context,
+        bounds: S,
+    ) -> Vec<T> {
+        let slice = self.slice(bounds);
+        slice.map_async(wgpu::MapMode::Read, |_| {});
+        context.device.poll(wgpu::Maintain::Wait);
+        let data: Vec<T> = bytemuck::cast_slice(slice.get_mapped_range().as_ref()).to_vec();
+        self.unmap();
+
+        data
+    }
+}
diff --git a/src/gfx/mod.rs b/src/gfx/mod.rs
index 49baf37..f6507eb 100644
--- a/src/gfx/mod.rs
+++ b/src/gfx/mod.rs
@@ -6,7 +6,7 @@ mod texture;
 
 pub use self::{
     bind_group::{BindGroupBuilder, BindGroupLayoutBuilder},
-    buffer::BulkBufferBuilder,
+    buffer::{BufferExt, BulkBufferBuilder},
     context::Context,
     renderer::Renderer,
     texture::{Texture, TextureBuilder},