implement TSkybox and use setColor method to set the background color, rather than the image

thermion_dart/lib/src/filament/src/implementation/ffi_filament_app.dart

@@ -1,6 +1,7 @@
 import 'dart:async';
 
 import 'package:thermion_dart/src/filament/src/implementation/ffi_camera.dart';
+import 'package:thermion_dart/src/filament/src/implementation/ffi_skybox.dart';
 import 'package:thermion_dart/src/filament/src/interface/scene.dart';
 import 'package:thermion_dart/src/filament/src/implementation/ffi_asset.dart';
 import 'package:thermion_dart/src/filament/src/implementation/ffi_gizmo.dart';
@@ -10,6 +11,7 @@ import 'package:thermion_dart/src/filament/src/implementation/ffi_scene.dart';
 import 'package:thermion_dart/src/filament/src/implementation/ffi_swapchain.dart';
 import 'package:thermion_dart/src/filament/src/implementation/ffi_texture.dart';
 import 'package:thermion_dart/src/filament/src/implementation/ffi_view.dart';
+import 'package:thermion_dart/src/filament/src/interface/skybox.dart';
 import 'package:thermion_dart/src/utils/src/matrix.dart';
 import 'package:thermion_dart/thermion_dart.dart';
 import 'package:logging/logging.dart';
@@ -1207,5 +1209,17 @@ class FFIFilamentApp extends FilamentApp<Pointer> {
         Vector3(bb.halfExtentX, bb.halfExtentY, bb.halfExtentZ));
   }
 
-
+  /// Builds an (empty) [Skybox] instance. This will not be attached to any scene until
+  /// [setSkybox] is called.
+  ///
+  Future<Skybox> buildSkybox({Texture? texture = null}) async {
+    final ptr = await withPointerCallback<TSkybox>((cb) {
+      Engine_buildSkyboxRenderThread(
+        engine,
+        (texture as FFITexture?)?.pointer ?? nullptr,
+        cb,
+      );
+    });
+    return FFISkybox(ptr);
+  }
 }

thermion_dart/lib/src/filament/src/implementation/ffi_scene.dart

@@ -1,6 +1,8 @@
 import 'package:thermion_dart/src/filament/src/implementation/ffi_asset.dart';
 import 'package:thermion_dart/src/filament/src/implementation/ffi_indirect_light.dart';
+import 'package:thermion_dart/src/filament/src/implementation/ffi_skybox.dart';
 import 'package:thermion_dart/src/filament/src/interface/scene.dart';
+import 'package:thermion_dart/src/filament/src/interface/skybox.dart';
 import 'package:thermion_dart/thermion_dart.dart';
 import 'package:logging/logging.dart';
 
@@ -153,4 +155,11 @@ class FFIScene extends Scene {
   Future<IndirectLight?> getIndirectLight() async {
     return _indirectLight;
   }
+
+  ///
+  ///
+  ///
+  Future setSkybox(Skybox skybox) async {
+    Scene_setSkybox(scene, (skybox as FFISkybox).pointer);
+  }
 }

thermion_dart/lib/src/filament/src/implementation/ffi_skybox.dart

@@ -0,0 +1,26 @@
+import 'package:thermion_dart/src/filament/src/implementation/ffi_filament_app.dart';
+import 'package:thermion_dart/src/filament/src/interface/skybox.dart';
+import 'package:thermion_dart/thermion_dart.dart';
+
+class FFISkybox extends Skybox {
+  final Pointer<TSkybox> pointer;
+
+  FFISkybox(this.pointer);
+
+  @override
+  Future setColor(double r, double g, double b, double a) async {
+    Skybox_setColor(pointer, r, g, b, a);
+  }
+
+  @override
+  Future destroy() async {
+    await withVoidCallback(
+      (requestId, cb) => Engine_destroySkyboxRenderThread(
+        (FilamentApp.instance as FFIFilamentApp).engine,
+        pointer,
+        requestId,
+        cb,
+      ),
+    );
+  }
+}

thermion_dart/lib/src/filament/src/interface/filament_app.dart

@@ -1,4 +1,5 @@
 import 'package:thermion_dart/src/filament/src/interface/scene.dart';
+import 'package:thermion_dart/src/filament/src/interface/skybox.dart';
 import 'package:thermion_dart/thermion_dart.dart';
 
 class FilamentConfig<T, U> {
@@ -344,19 +345,23 @@ abstract class FilamentApp<T> {
   Future<Matrix4> getWorldTransform(ThermionEntity entity);
 
   /// Sets the render priority for [entity].
-  /// [priority] should be be between 0 and 7, with 0 meaning highest priority 
+  /// [priority] should be be between 0 and 7, with 0 meaning highest priority
   /// (rendered first) and 7 meaning lowest priority (rendered last).
   ///
   Future setPriority(ThermionEntity entity, int priority);
 
-  /// Gets the number of primitives for [entity] (which is assumed to be 
+  /// Gets the number of primitives for [entity] (which is assumed to be
   /// have a renderable component attached)
   ///
   Future<int> getPrimitiveCount(ThermionEntity entity);
 
-  /// Gets the bounding box for [entity] (which is assumed to be 
+  /// Gets the bounding box for [entity] (which is assumed to be
   /// have a renderable component attached).
   ///
   Future<Aabb3> getBoundingBox(ThermionEntity entity);
 
+  /// Builds a [Skybox] instance. This will not be attached to any scene until
+  /// [setSkybox] is called.
+  ///
+  Future<Skybox> buildSkybox({Texture? texture = null});
 }

thermion_dart/lib/src/filament/src/interface/scene.dart

@@ -1,3 +1,4 @@
+import 'package:thermion_dart/src/filament/src/interface/skybox.dart';
 import 'package:thermion_dart/thermion_dart.dart';
 
 abstract class Scene {
@@ -49,4 +50,11 @@ abstract class Scene {
   Future<IndirectLight?> getIndirectLight() {
     throw UnimplementedError();
   }
+
+  ///
+  ///
+  ///
+  Future setSkybox(Skybox skybox) {
+    throw UnimplementedError();
+  }
 }

thermion_dart/lib/src/filament/src/interface/skybox.dart

@@ -0,0 +1,11 @@
+abstract class Skybox {
+  ///
+  ///
+  ///
+  Future setColor(double r, double g, double b, double a);
+
+  ///
+  ///
+  ///
+  Future destroy();
+}