gpu: implement BindGroup

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

gpu/src/BindGroup.zig

@@ -0,0 +1,27 @@
+const BindGroup = @This();
+
+/// The type erased pointer to the BindGroup implementation
+/// Equal to c.WGPUBindGroup for NativeInstance.
+ptr: *anyopaque,
+vtable: *const VTable,
+
+pub const VTable = struct {
+    reference: fn (ptr: *anyopaque) void,
+    release: fn (ptr: *anyopaque) void,
+    // TODO:
+    // WGPU_EXPORT void wgpuBindGroupSetLabel(WGPUBindGroup bindGroup, char const * label);
+};
+
+pub inline fn reference(group: BindGroup) void {
+    group.vtable.reference(group.ptr);
+}
+
+pub inline fn release(group: BindGroup) void {
+    group.vtable.release(group.ptr);
+}
+
+test "syntax" {
+    _ = VTable;
+    _ = reference;
+    _ = release;
+}