[rs] create_buffer_with_data automatically handles its own alignment requirements

wgpu/src/lib.rs

@@ -1233,15 +1233,24 @@ impl Device {
     /// Creates a new buffer, maps it into host-visible memory, copies data from the given slice,
     /// and finally unmaps it, returning a [`Buffer`].
     pub fn create_buffer_with_data(&self, data: &[u8], usage: BufferUsage) -> Buffer {
-        let size = data.len() as u64;
+        let align = COPY_BUFFER_ALIGNMENT;
+        let unpadded_size = data.len() as u64;
+        let padding = (align - unpadded_size % align) % align;
+        let padded_size = unpadded_size + padding;
+
         let buffer = self.create_buffer(&BufferDescriptor {
             label: None,
-            size,
+            size: padded_size,
             usage,
             mapped_at_creation: true,
         });
-        Context::buffer_get_mapped_range_mut(&*self.context, &buffer.id, 0..size)
-            .copy_from_slice(data);
+
+        let range = Context::buffer_get_mapped_range_mut(&*self.context, &buffer.id, 0..padded_size);
+        range[0..unpadded_size as usize].copy_from_slice(&data);
+        for i in unpadded_size..padded_size {
+            range[i as usize] = 0;
+        }
+
         buffer.unmap();
         buffer
     }