From 1848ac8ac7e59e36b3dd0c9441405892e508db3a Mon Sep 17 00:00:00 2001
From: Stephen Gutekanst <stephen@hexops.com>
Date: Thu, 11 Aug 2022 06:25:55 -0700
Subject: [PATCH] gpu: make CommandEncoder.writeBuffer use a slice helper

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
---
 gpu/README.md               |  2 +-
 gpu/src/command_encoder.zig | 17 +++++++++++++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/gpu/README.md b/gpu/README.md
index 93b98534..ceb3c8dd 100644
--- a/gpu/README.md
+++ b/gpu/README.md
@@ -152,6 +152,7 @@ Some WebGPU APIs expose slices as pointers and lengths, we either wrap these to
 The slice helpers are:
 
 * `Adapter.enumerateFeaturesOwned`
+* `CommandEncoder.writeBuffer`
 * `Queue.writeTexture`
 * `Queue.writeBuffer`
 
@@ -217,7 +218,6 @@ The following are definitive candidates for helpers we haven't implemented yet:
 
 * `gpu.Buffer.getConstMappedRange` (slices)
 * `gpu.Buffer.getMappedRange` (slices)
-* `gpu.CommandEncoder.writeBuffer` (slices)
 * `gpu.ComputePassEncoder.setBindGroup` (slice param)
 * `gpu.Device.enumerateFeatures` (owned slice)
 * `gpu.RenderBundleEncoder.setBindGroup` (slice param)
diff --git a/gpu/src/command_encoder.zig b/gpu/src/command_encoder.zig
index a2de1ac1..1d95182d 100644
--- a/gpu/src/command_encoder.zig
+++ b/gpu/src/command_encoder.zig
@@ -81,8 +81,21 @@ pub const CommandEncoder = opaque {
         Impl.commandEncoderSetLabel(command_encoder, label);
     }
 
-    pub inline fn writeBuffer(command_encoder: *CommandEncoder, buffer: *Buffer, buffer_offset: u64, data: [*]const u8, size: u64) void {
-        Impl.commandEncoderWriteBuffer(command_encoder, buffer, buffer_offset, data, size);
+    pub inline fn writeBuffer(
+        command_encoder: *CommandEncoder,
+        buffer: *Buffer,
+        buffer_offset_bytes: u64,
+        data_slice: anytype,
+    ) void {
+        Impl.commandEncoderWriteBuffer(
+            command_encoder,
+            buffer,
+            buffer_offset_bytes,
+            data,
+            size,
+            @ptrCast([*]const u8, data_slice.ptr),
+            @intCast(u64, data_slice.len) * @sizeOf(std.meta.Elem(@TypeOf(data_slice))),
+        );
     }
 
     pub inline fn writeTimestamp(command_encoder: *CommandEncoder, query_set: *QuerySet, query_index: u32) void {