gpu: implement Sampler

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

gpu/src/Sampler.zig

@@ -0,0 +1,27 @@
+const Sampler = @This();
+
+/// The type erased pointer to the Sampler implementation
+/// Equal to c.WGPUSampler 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 wgpuSamplerSetLabel(WGPUSampler sampler, char const * label);
+};
+
+pub inline fn reference(sampler: Sampler) void {
+    sampler.vtable.reference(sampler.ptr);
+}
+
+pub inline fn release(sampler: Sampler) void {
+    sampler.vtable.release(sampler.ptr);
+}
+
+test "syntax" {
+    _ = VTable;
+    _ = reference;
+    _ = release;
+}