add viewer/windows files

windows/include/polyvox_filament/polyvox_filament_plugin.h

@@ -0,0 +1,23 @@
+#ifndef FLUTTER_PLUGIN_POLYVOX_FILAMENT_PLUGIN_H_
+#define FLUTTER_PLUGIN_POLYVOX_FILAMENT_PLUGIN_H_
+
+#include <flutter_plugin_registrar.h>
+
+#ifdef FLUTTER_PLUGIN_IMPL
+#define FLUTTER_PLUGIN_EXPORT __declspec(dllexport)
+#else
+#define FLUTTER_PLUGIN_EXPORT __declspec(dllimport)
+#endif
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+FLUTTER_PLUGIN_EXPORT void PolyvoxFilamentPluginRegisterWithRegistrar(
+    FlutterDesktopPluginRegistrarRef registrar);
+
+#if defined(__cplusplus)
+}  // extern "C"
+#endif
+
+#endif  // FLUTTER_PLUGIN_POLYVOX_FILAMENT_PLUGIN_H_