add createRenderTargetRenderThread

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

@@ -1487,6 +1487,19 @@ external void Viewer_captureRenderTargetRenderThread(
   ffi.Pointer<ffi.NativeFunction<ffi.Void Function()>> onComplete,
 );
 
+@ffi.Native<
+    ffi.Pointer<TRenderTarget> Function(
+        ffi.Pointer<TViewer>, ffi.IntPtr, ffi.Uint32, ffi.Uint32, 
+        ffi.Pointer<ffi.NativeFunction<ffi.Void Function(ffi.Pointer<TRenderTarget>)>>
+        )>(isLeaf: true)
+external ffi.Pointer<TRenderTarget> Viewer_createRenderTargetRenderThread(
+  ffi.Pointer<TViewer> viewer,
+  int texture,
+  int width,
+  int height,
+  ffi.Pointer<ffi.NativeFunction<ffi.Void Function(ffi.Pointer<TRenderTarget>)>> onComplete,
+);
+
 @ffi.Native<
     ffi.Void Function(ffi.Pointer<TViewer>,
         ffi.Pointer<ffi.NativeFunction<ffi.Void Function()>>)>(isLeaf: true)

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

@@ -101,8 +101,10 @@ class ThermionViewerFFI extends ThermionViewer {
   ///
   Future<RenderTarget> createRenderTarget(
       int width, int height, int textureHandle) async {
-    final renderTarget =
+    final renderTarget = await withPointerCallback<TRenderTarget>((cb) {
-        Viewer_createRenderTarget(_viewer!, textureHandle, width, height);
+      Viewer_createRenderTargetRenderThread(_viewer!, textureHandle, width, height, cb);
+    });
+        
     return FFIRenderTarget(renderTarget, _viewer!);
   }
 

thermion_dart/native/include/ThermionDartRenderThreadApi.h

@@ -36,6 +36,7 @@ extern "C"
     EMSCRIPTEN_KEEPALIVE void Viewer_captureRenderTargetRenderThread(TViewer *viewer, TView* view,  TSwapChain* swapChain, TRenderTarget* renderTarget, uint8_t* out, void (*onComplete)());
     EMSCRIPTEN_KEEPALIVE void Viewer_requestFrameRenderThread(TViewer *viewer, void(*onComplete)());
     EMSCRIPTEN_KEEPALIVE void Viewer_loadIblRenderThread(TViewer *viewer, const char *iblPath, float intensity, void(*onComplete)());
+    EMSCRIPTEN_KEEPALIVE void Viewer_createRenderTargetRenderThread(TViewer *viewer, intptr_t texture, uint32_t width, uint32_t height, void(*onComplete)(TRenderTarget*));
     
     EMSCRIPTEN_KEEPALIVE void View_setToneMappingRenderThread(TView *tView, TEngine *tEngine, thermion::ToneMapping toneMapping);
     EMSCRIPTEN_KEEPALIVE void View_setBloomRenderThread(TView *tView, double bloom);

thermion_dart/native/src/ThermionDartRenderThreadApi.cpp

@@ -263,6 +263,16 @@ extern "C"
       auto fut = _rl->add_task(lambda);
   }
 
+  EMSCRIPTEN_KEEPALIVE void Viewer_createRenderTargetRenderThread(TViewer *viewer, intptr_t texture, uint32_t width, uint32_t height, void(*onComplete)(TRenderTarget*)) {
+    std::packaged_task<void()> lambda(
+        [=]() mutable
+        {
+          auto renderTarget = Viewer_createRenderTarget(viewer, texture, width, height);
+          onComplete(renderTarget);
+        });
+      auto fut = _rl->add_task(lambda);
+  }
+
   EMSCRIPTEN_KEEPALIVE void
   set_frame_interval_render_thread(TViewer *viewer, float frameIntervalInMilliseconds)
   {