Add GPUComandEncoder.fillBuffer() (#2208)

litherum · web-flow · commit cee9ad6c4def · 2021-10-26T22:51:57.000Z
Add GPUComandEncoder.fillBuffer() (#2208) Fixes #1968. In the future, we can add a 4th parameter, `value`, of type `octet` or `byte`. For now, though, the group seems to have just agreed on zeroing, rather than filling with a particular byte. There are two commits in this PR, one that requires `GPUBufferUsage.STORAGE` on the buffer, and a second that relaxes this requirement because of #1968 (comment).
diff --git a/spec/index.bs b/spec/index.bs
@@ -5527,6 +5527,11 @@ interface GPUCommandEncoder {
         GPUImageCopyTexture destination,
         GPUExtent3D copySize);
 
+    undefined fillBuffer(
+        GPUBuffer destination,
+        GPUSize64 destinationOffset,
+        GPUSize64 size);
+
     undefined pushDebugGroup(USVString groupLabel);
     undefined popDebugGroup();
     undefined insertDebugMarker(USVString markerLabel);
@@ -5982,6 +5987,38 @@ dictionary GPUImageCopyExternalImage {
         </div>
 </dl>
 
+### Buffer Fills ### {#buffer-fills}
+
+<dl dfn-type=method dfn-for=GPUCommandEncoder>
+    : <dfn>fillBuffer(destination, destinationOffset, size)</dfn>
+    ::
+        Encode a command into the {{GPUCommandEncoder}} that fills a sub-region of a
+        {{GPUBuffer}} with zeros.
+
+        <div algorithm=GPUCommandEncoder.fillBuffer>
+            **Called on:** {{GPUCommandEncoder}} |this|.
+
+            **Arguments:**
+            <pre class=argumentdef for="GPUCommandEncoder/fillBuffer(destination, destinationOffset, size)">
+                |destination|: The {{GPUBuffer}} to write to.
+                |destinationOffset|: Offset in bytes into |destination| to place the data.
+                |size|: Bytes to copy.
+            </pre>
+
+            **Returns:** {{undefined}}
+
+            If any of the following conditions are unsatisfied, generate a validation error and stop.
+            <div class=validusage>
+                - |this|.{{GPUCommandEncoder/[[state]]}} is {{encoder state/open}}.
+                - |destination| is [$valid to use with$] |this|.
+                - |destination|.{{GPUBuffer/[[usage]]}} contains {{GPUBufferUsage/COPY_DST}}.
+                - |size| is a multiple of 4.
+                - |destinationOffset| is a multiple of 4.
+                - |destination|.{{GPUBuffer/[[size]]}} is greater than or equal to (|destinationOffset| + |size|).
+            </div>
+        </div>
+</dl>
+
 ### Image Copies ### {#image-copies}
 
 WebGPU provides {{GPUCommandEncoder/copyBufferToTexture()}} for buffer-to-texture copies and
