Allow studio to search for models in predetermined search paths.

A future CL will allow users to specify search paths in their settings.

PiperOrigin-RevId: 846240293
Change-Id: I1a1a4027d0fc85004a12fe01a406f50fd929f3e4

src/experimental/studio/app.cc

@@ -201,10 +201,12 @@ void App::LoadModel(std::string data, ContentType type) {
       // Store the file path as the model name. Note that we use this model name
       // to perform reload operations.
       model_name_ = std::move(data);
-      if (model_name_.ends_with(".mjb")) {
-        model_ = mj_loadModel(model_name_.c_str(), 0);
-      } else if (model_name_.ends_with(".xml")) {
-        spec_ = mj_parseXML(model_name_.c_str(), nullptr, err, sizeof(err));
+      const std::string resolved_file =
+        platform::ResolveFile(model_name_, search_paths_);
+    if (resolved_file.ends_with(".mjb")) {
+        model_ = mj_loadModel(resolved_file.c_str(), 0);
+      } else if (resolved_file.ends_with(".xml")) {
+        spec_ = mj_parseXML(resolved_file.c_str(), nullptr, err, sizeof(err));
         if (spec_ && err[0] == 0) {
           model_ = mj_compile(spec_, nullptr);
         }

src/experimental/studio/app.h

@@ -185,6 +185,8 @@ class App {
   platform::SimProfiler profiler_;
   platform::SimHistory history_;
 
+  std::vector<std::string> search_paths_;
+
   mjSpec* spec_ = nullptr;
   mjModel* model_ = nullptr;
   mjData* data_ = nullptr;