gpu: implement Buffer

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

gpu/src/Buffer.zig

@@ -0,0 +1,32 @@
+const Buffer = @This();
+
+/// The type erased pointer to the Buffer implementation
+/// Equal to c.WGPUBuffer 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 wgpuBufferDestroy(WGPUBuffer buffer);
+    // WGPU_EXPORT void const * wgpuBufferGetConstMappedRange(WGPUBuffer buffer, size_t offset, size_t size);
+    // WGPU_EXPORT void * wgpuBufferGetMappedRange(WGPUBuffer buffer, size_t offset, size_t size);
+    // WGPU_EXPORT void wgpuBufferMapAsync(WGPUBuffer buffer, WGPUMapModeFlags mode, size_t offset, size_t size, WGPUBufferMapCallback callback, void * userdata);
+    // WGPU_EXPORT void wgpuBufferSetLabel(WGPUBuffer buffer, char const * label);
+    // WGPU_EXPORT void wgpuBufferUnmap(WGPUBuffer buffer);
+};
+
+pub inline fn reference(buffer: Buffer) void {
+    buffer.vtable.reference(buffer.ptr);
+}
+
+pub inline fn release(buffer: Buffer) void {
+    buffer.vtable.release(buffer.ptr);
+}
+
+test "syntax" {
+    _ = VTable;
+    _ = reference;
+    _ = release;
+}