initial work to split into dart_filament and flutter_filament

dart_filament/example_cli/bin/example_cli.dart

@@ -0,0 +1,42 @@
+import 'dart:ffi';
+import 'dart:io';
+import 'package:dart_filament/dart_filament/swift/swift_bindings.g.dart';
+import 'package:dart_filament/dart_filament/utils/dart_resources.dart';
+import 'package:ffi/ffi.dart';
+import 'package:dart_filament/dart_filament.dart';
+import 'package:dart_filament/dart_filament/dart_filament.g.dart';
+
+void main() async {
+  var testDir = File(Platform.script.toFilePath()).parent.path;
+  final lib = DartFilamentTexture1(DynamicLibrary.open(
+      '../native/lib/macos/swift/libdartfilamenttexture.dylib'));
+  final object = DartFilamentTexture.new1(lib);
+  object.initWithWidth_height_(500, 500);
+
+  final resourceLoader = calloc<ResourceLoaderWrapper>(1);
+  var loadToOut = NativeCallable<
+      Void Function(Pointer<Char>,
+          Pointer<ResourceBuffer>)>.listener(DartResourceLoader.loadResource);
+
+  resourceLoader.ref.loadToOut = loadToOut.nativeFunction;
+  var freeResource = NativeCallable<Void Function(ResourceBuffer)>.listener(
+      DartResourceLoader.freeResource);
+  resourceLoader.ref.freeResource = freeResource.nativeFunction;
+
+  var viewer = FilamentViewer(resourceLoader: resourceLoader);
+
+  await viewer.initialized;
+  await viewer.createSwapChain(500, 500);
+  await viewer.createRenderTarget(500, 500, object.metalTextureAddress);
+  await viewer.updateViewportAndCameraProjection(500, 500);
+
+  var outDir = Directory("$testDir/skybox");
+  outDir.createSync();
+  await viewer.setRecordingOutputDirectory(outDir.path);
+  await viewer.setRecording(true);
+  await viewer.loadSkybox(
+      "file:///$testDir/../../../flutter_filament/example/assets/default_env/default_env_skybox.ktx");
+  await Future.delayed(Duration(milliseconds: 16));
+  await viewer.render();
+  await viewer.dispose();
+}