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

thermion_dart/lib/src/bindings/src/thermion_dart_ffi.g.dart

@@ -636,7 +636,6 @@ external bool Texture_loadImage(
   int level,
 );
 
-
 @ffi.Native<
     ffi.Bool Function(
         ffi.Pointer<TEngine>,
@@ -651,7 +650,6 @@ external bool Texture_loadImage(
         ffi.Uint32,
         ffi.Uint32,
         ffi.Uint32,
-        ffi.Uint32,
         ffi.Uint32)>(isLeaf: true)
 external bool Texture_setImage(
   ffi.Pointer<TEngine> tEngine,
@@ -664,7 +662,6 @@ external bool Texture_setImage(
   int z_offset,
   int width,
   int height,
-  int channels,
   int depth,
   int bufferFormat,
   int pixelDataType,
@@ -1618,6 +1615,11 @@ external int EntityManager_createEntity(
   ffi.Pointer<TEntityManager> tEntityManager,
 );
 
+@ffi.Native<ffi.Void Function(ffi.Pointer<TFence>)>(isLeaf: true)
+external void Fence_waitAndDestroy(
+  ffi.Pointer<TFence> tFence,
+);
+
 @ffi.Native<ffi.Void Function()>(isLeaf: true)
 external void RenderThread_create();
 
@@ -1941,6 +1943,14 @@ external void Engine_createFenceRenderThread(
       onComplete,
 );
 
+@ffi.Native<ffi.Void Function(ffi.Pointer<TFence>, ffi.Uint32, VoidCallback)>(
+    isLeaf: true)
+external void Fence_waitAndDestroyRenderThread(
+  ffi.Pointer<TFence> tFence,
+  int requestId,
+  VoidCallback onComplete,
+);
+
 @ffi.Native<
     ffi.Void Function(ffi.Pointer<TEngine>, ffi.Pointer<TFence>, ffi.Uint32,
         VoidCallback)>(isLeaf: true)
@@ -2507,7 +2517,6 @@ external void Texture_loadImageRenderThread(
   ffi.Pointer<ffi.NativeFunction<ffi.Void Function(ffi.Bool)>> onComplete,
 );
 
-
 @ffi.Native<
         ffi.Void Function(
             ffi.Pointer<TEngine>,
@@ -2945,6 +2954,17 @@ external bool GltfResourceLoader_loadResources(
   ffi.Pointer<TFilamentAsset> tFilamentAsset,
 );
 
+@ffi.Native<
+    ffi.Void Function(ffi.Pointer<TSkybox>, ffi.Double, ffi.Double, ffi.Double,
+        ffi.Double)>(isLeaf: true)
+external void Skybox_setColor(
+  ffi.Pointer<TSkybox> tSkybox,
+  double r,
+  double g,
+  double b,
+  double a,
+);
+
 @ffi.Native<
     ffi.Bool Function(ffi.Pointer<TRenderableManager>, EntityId, ffi.Int,
         ffi.Pointer<TMaterialInstance>)>(isLeaf: true)

thermion_dart/lib/src/bindings/src/thermion_dart_js_interop.g.dart

@@ -1956,6 +1956,13 @@ extension type NativeLibrary(JSObject _) implements JSObject {
     Pointer<TGltfResourceLoader> tGltfResourceLoader,
     Pointer<TFilamentAsset> tFilamentAsset,
   );
+  external void _Skybox_setColor(
+    Pointer<TSkybox> tSkybox,
+    double r,
+    double g,
+    double b,
+    double a,
+  );
   external int _RenderableManager_setMaterialInstanceAt(
     Pointer<TRenderableManager> tRenderableManager,
     EntityId entityId,
@@ -5509,6 +5516,17 @@ bool GltfResourceLoader_loadResources(
   return result == 1;
 }
 
+void Skybox_setColor(
+  self.Pointer<TSkybox> tSkybox,
+  double r,
+  double g,
+  double b,
+  double a,
+) {
+  final result = _lib._Skybox_setColor(tSkybox.cast(), r, g, b, a);
+  return result;
+}
+
 bool RenderableManager_setMaterialInstanceAt(
   self.Pointer<TRenderableManager> tRenderableManager,
   DartEntityId entityId,

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();
+}

thermion_dart/lib/src/viewer/src/ffi/src/thermion_viewer_ffi.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 import 'package:thermion_dart/src/filament/src/implementation/background_image.dart';
 import 'package:thermion_dart/src/filament/src/implementation/ffi_indirect_light.dart';
 import 'package:thermion_dart/src/filament/src/implementation/ffi_ktx1_bundle.dart';
+import 'package:thermion_dart/src/filament/src/implementation/ffi_skybox.dart';
 import 'package:thermion_dart/src/filament/src/implementation/ffi_swapchain.dart';
 import 'package:thermion_dart/src/filament/src/implementation/ffi_texture.dart';
 import '../../../../filament/src/implementation/ffi_asset.dart';
@@ -229,13 +230,10 @@ class ThermionViewerFFI extends ThermionViewer {
   ///
   @override
   Future setBackgroundColor(double r, double g, double b, double a) async {
-    // we don't want to use the Renderer clearColor, because this only applies
-    // to clearing the swapchain. Even if this Viewer is rendered into the
-    // swapchain, we don't necessarily (?) want to set the clear color,
-    // because that will affect other views.
-    // We therefore use the background image as the color;
-    _backgroundImage ??= await BackgroundImage.create(this, scene);
-    await _backgroundImage!.setBackgroundColor(r, g, b, a);
+    await removeSkybox();
+    _skybox = await FilamentApp.instance!.buildSkybox() as FFISkybox;
+    await scene.setSkybox(_skybox!);
+    await _skybox!.setColor(r, g, b, a);
   }
 
   ///
@@ -252,7 +250,7 @@ class ThermionViewerFFI extends ThermionViewer {
 
   Future? _skyboxTextureUploadComplete;
   FFITexture? _skyboxTexture;
-  Pointer<TSkybox>? _skybox;
+  FFISkybox? _skybox;
 
   ///
   ///
@@ -271,10 +269,11 @@ class ThermionViewerFFI extends ThermionViewer {
 
       _skyboxTexture = await bundle.createTexture() as FFITexture;
 
-      _skybox = await withPointerCallback<TSkybox>((cb) {
-        Engine_buildSkyboxRenderThread(app.engine, _skyboxTexture!.pointer, cb);
-      });
-      Scene_setSkybox(scene.scene, _skybox!);
+      _skybox = await FilamentApp.instance!.buildSkybox(texture: _skyboxTexture)
+          as FFISkybox;
+
+      await scene.setSkybox(_skybox!);
+
       completer.complete();
     }).then((_) async {
       _skyboxTextureUploadComplete = null;
@@ -364,16 +363,7 @@ class ThermionViewerFFI extends ThermionViewer {
       _skyboxTextureUploadComplete = null;
     }
 
-    if (_skybox != null) {
-      await withVoidCallback(
-        (requestId, cb) => Engine_destroySkyboxRenderThread(
-          app.engine,
-          _skybox!,
-          requestId,
-          cb,
-        ),
-      );
-    }
+    await _skybox?.destroy();
     _skybox = null;
     _skyboxTexture = null;
   }

thermion_dart/native/include/c_api/TSkybox.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include "APIExport.h"
+#include "APIBoundaryTypes.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+EMSCRIPTEN_KEEPALIVE void Skybox_setColor(TSkybox* tSkybox, double r, double g, double b, double a);
+
+#ifdef __cplusplus
+}
+#endif
+

thermion_dart/native/src/c_api/TSkybox.cpp

@@ -0,0 +1,30 @@
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#endif 
+
+#include "c_api/TSkybox.h"
+
+#include <filament/math/mat4.h>
+#include <filament/Skybox.h>
+
+#include "Log.hpp"
+
+#ifdef __cplusplus
+namespace thermion
+{
+    extern "C"
+    {
+        using namespace filament;
+#endif
+
+        EMSCRIPTEN_KEEPALIVE void Skybox_setColor(TSkybox *tSkybox, double r, double g, double b, double a)
+        {
+            auto *skybox = reinterpret_cast<filament::Skybox *>(tSkybox);
+            skybox->setColor(filament::math::float4 { static_cast<float>(r), static_cast<float>(g), static_cast<float>(b), static_cast<float>(a) } );
+        }
+        
+
+#ifdef __cplusplus
+    }
+}
+#endif