gpu: implement RenderBundle

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

gpu/src/RenderBundle.zig

@@ -0,0 +1,26 @@
+const RenderBundle = @This();
+
+/// The type erased pointer to the RenderBundle implementation
+/// Equal to c.WGPURenderBundle for NativeInstance.
+ptr: *anyopaque,
+vtable: *const VTable,
+
+pub const VTable = struct {
+    reference: fn (ptr: *anyopaque) void,
+    release: fn (ptr: *anyopaque) void,
+    // TODO:
+};
+
+pub inline fn reference(bundle: RenderBundle) void {
+    bundle.vtable.reference(bundle.ptr);
+}
+
+pub inline fn release(bundle: RenderBundle) void {
+    bundle.vtable.release(bundle.ptr);
+}
+
+test "syntax" {
+    _ = VTable;
+    _ = reference;
+    _ = release;
+}