Reset free camera when loading a new model.

PiperOrigin-RevId: 871622663
Change-Id: I1f1a4681752f7436c7bc7adbe64dcea286c5620c

src/experimental/studio/app.cc

@@ -149,6 +149,7 @@ void App::RequestModelLoad(std::string model_file) {
 void App::RequestModelReload() {
   if (model_kind_ == kModelFromFile) {
     pending_load_ = model_path_;
+    preserve_camera_on_load_ = true;
   }
 }
 
@@ -199,6 +200,16 @@ void App::OnModelLoaded(std::string filename, ModelKind model_kind) {
   const int state_size = mj_stateSize(model, mjSTATE_INTEGRATION);
   history_.Init(state_size);
 
+  if (!preserve_camera_on_load_) {
+    const int model_cam = model->vis.global.cameraid;
+    if (model_cam >= 0 && model_cam < model->ncam) {
+      ui_.camera_idx = platform::SetCamera(model, &camera_, model_cam);
+    } else {
+      mjv_defaultFreeCamera(model, &camera_);
+    }
+  }
+  preserve_camera_on_load_ = false;
+
   // Initialize the speed based on the model's default real-time setting.
   float min_error = FLT_MAX;
   const float desired = mju_log(100 * model->vis.global.realtime);

src/experimental/studio/app.h

@@ -232,6 +232,7 @@ class App {
   std::string load_error_;
   std::string step_error_;
   std::optional<std::string> pending_load_;
+  bool preserve_camera_on_load_ = false;
   ModelKind model_kind_ = kEmptyModel;
 
   std::unique_ptr<platform::Window> window_;