gpu: add RenderBundleEncoder.Descriptor.init slice helper

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

gpu/README.md

@@ -172,6 +172,7 @@ And, to initialize data structures with slices in them, the following helpers ar
 * `Device.Descriptor.init`
 * `PipelineLayout.Descriptor.init`
 * `QuerySet.Descriptor.init`
+* `RenderBundleEncoder.Descriptor.init`
 
 ### Typed callbacks
 

gpu/src/render_bundle_encoder.zig

@@ -11,13 +11,34 @@ pub const RenderBundleEncoder = opaque {
     pub const Descriptor = extern struct {
         next_in_chain: ?*const ChainedStruct = null,
         label: ?[*:0]const u8 = null,
-        // TODO: slice helper
         color_formats_count: u32 = 0,
         color_formats: ?[*]const Texture.Format = null,
         depth_stencil_format: Texture.Format = .undef,
         sample_count: u32 = 1,
         depth_read_only: bool = false,
         stencil_read_only: bool = false,
+
+        /// Provides a slightly friendlier Zig API to initialize this structure.
+        pub inline fn init(v: struct {
+            next_in_chain: ?*const ChainedStruct = null,
+            label: ?[*:0]const u8 = null,
+            color_formats: ?[]const Texture.Format = null,
+            depth_stencil_format: Texture.Format = .undef,
+            sample_count: u32 = 1,
+            depth_read_only: bool = false,
+            stencil_read_only: bool = false,
+        }) Descriptor {
+            return .{
+                .next_in_chain = v.next_in_chain,
+                .label = v.label,
+                .color_formats_count = if (v.color_formats) |e| @intCast(u32, e.len) else 0,
+                .color_formats = if (v.color_formats) |e| e.ptr else null,
+                .depth_stencil_format = v.depth_stencil_format,
+                .sample_count = v.sample_count,
+                .depth_read_only = v.depth_read_only,
+                .stencil_read_only = v.stencil_read_only,
+            };
+        }
     };
 
     /// Default `instance_count`: 1