Improve error/warning display in studio.

PiperOrigin-RevId: 940299502
Change-Id: I8b13e2f984627a638a01b52f7dadca43f2c2ca80

src/experimental/platform/sim/model_holder.cc

@@ -17,7 +17,7 @@
 #include <cstddef>
 #include <cstring>
 #include <memory>
-#include <span>
+#include <span>  // NOLINT
 #include <string_view>
 
 #include <mujoco/mujoco.h>
@@ -89,6 +89,11 @@ void ModelHolder::PostInit() {
       SetLoadError(mjs_getError(spec_));
       return;
     }
+    int num_warnings = mjs_numWarnings(spec_);
+    for (int i = 0; i < num_warnings; ++i) {
+      if (!warning_.empty()) warning_ += '\n';
+      warning_ += mjs_getWarning(spec_, i);
+    }
   }
   data_ = mj_makeData(model_);
   if (!data_) {

src/experimental/platform/sim/model_holder.h

@@ -17,7 +17,8 @@
 
 #include <memory>
 #include <cstddef>
-#include <span>
+#include <span>  // NOLINT
+#include <string>
 #include <string_view>
 
 #include <mujoco/mujoco.h>
@@ -56,6 +57,9 @@ class ModelHolder {
   // Returns the error message if the model failed to load.
   std::string_view error() const { return error_; }
 
+  // Returns the warning message(s), newline-separated.
+  std::string_view warning() const { return warning_; }
+
   // Releases ownership of the underlying MuJoCo structures. Callers are now
   // responsible for calling the appropriate `mj_delete*` function on these
   // objects.
@@ -78,6 +82,7 @@ class ModelHolder {
   mjModel* model_ = nullptr;
   mjData* data_ = nullptr;
   char error_[1000] = "";
+  std::string warning_;
 };
 }  // namespace mujoco::platform
 

src/experimental/platform/ux/imgui_widgets.cc

@@ -505,18 +505,6 @@ void DrawTextAt(const char* text, float x, float y, float z) {
 }
 namespace {
 
-float MeasureTextWidth(const char* text) {
-  float max_width = 0.0f;
-  const char* start = text;
-  while (*start) {
-    const char* end = start;
-    while (*end && *end != '\n') ++end;
-    max_width = std::max(max_width, ImGui::CalcTextSize(start, end).x);
-    start = *end ? end + 1 : end;
-  }
-  return max_width;
-}
-
 void SetNextWindowPosInside(OverlayPos pos, ImVec4 rect) {
   // compute anchor point and pivot from position enum
   ImVec2 anchor, pivot;
@@ -584,7 +572,7 @@ void TextOverlay(const char* id, OverlayPos pos, ImVec4 workspace_rect,
   float scale = ImGui::GetWindowDpiScale();
   float padding = 30.0f * scale;
   float max_width = std::max(0.0f, workspace_rect.z - 20.0f);
-  float text_width = MeasureTextWidth(text) * font_scale;
+  float text_width = ImGui::CalcTextSize(text).x * font_scale;
   float min_target = std::min(min_width * scale, max_width);
   float target = 0.0f;
   if (text_width + padding > max_width || min_width > 0.0f) {

src/experimental/studio/app.cc

@@ -196,13 +196,16 @@ void App::OnModelLoaded(std::string filename, ModelKind model_kind) {
   step_error_ = "";
   edit_error_ = "";
 
+  if (!model_holder_->warning().empty()) {
+    load_error_ = model_holder_->warning();
+  }
   model_path_ = std::move(filename);
 
   if (model_kind_ == kEmptyModel) {
     step_control_.SetPauseState(PauseState::kUnpaused);
   }
   model_kind_ = model_kind;
-  if (model_kind_ == kEmptyModel) {
+  if (model_kind_ == kEmptyModel || !load_error_.empty()) {
     step_control_.SetPauseState(PauseState::kNormalPaused);
   }
 
@@ -240,6 +243,7 @@ void App::OnModelLoaded(std::string filename, ModelKind model_kind) {
     }
   });
   tmp_.update_threadpool = true;
+  last_pause_state_ = step_control_.GetPauseState();
 }
 
 void App::UpdateFilePaths(const std::string& resolved_path) {
@@ -377,6 +381,12 @@ bool App::Update() {
 
   ProcessPendingLoads();
 
+  PauseState current_pause = step_control_.GetPauseState();
+  if (current_pause != last_pause_state_) {
+    load_error_ = "";
+    last_pause_state_ = current_pause;
+  }
+
   // Only update the simulation if a popup window is not open. Note that the
   // simulation itself will only update if it is not paused.
   if (tmp_.file_dialog == UiTempState::FileDialog_None) {
@@ -987,6 +997,40 @@ void App::BuildGui() {
     ImGui::End();
   }
 
+  if (!load_error_.empty()) {
+    const float scale = ImGui::GetWindowDpiScale();
+    const float max_line_width =
+        ImGui::CalcTextSize(load_error_.c_str()).x;
+    const float padding = 30.0f * scale;
+    const float max_workspace_width = std::max(0.0f, workspace_rect.z - 20.0f);
+    const float min_target_width = std::min(350.0f * scale, max_workspace_width);
+    const float target_width = std::clamp(max_line_width + padding,
+                                          min_target_width, max_workspace_width);
+
+    if (platform::BeginOverlay("WarningOverlay", platform::OverlayPos::kBottom,
+                               workspace_rect, target_width, 0.8f)) {
+      const bool is_dark = ImGui::GetStyle().Colors[ImGuiCol_WindowBg].x < 0.5f;
+      if (!model_holder_->warning().empty()) {
+        const ImVec4 warning_color = is_dark ? ImVec4(1.0f, 0.8f, 0.2f, 1.0f)
+                                             : ImVec4(0.7f, 0.45f, 0.0f, 1.0f);
+        ImGui::TextColored(warning_color, "Warning:");
+      } else {
+        const ImVec4 error_color = is_dark ? ImVec4(1.0f, 0.4f, 0.4f, 1.0f)
+                                           : ImVec4(0.8f, 0.1f, 0.1f, 1.0f);
+        ImGui::TextColored(error_color, "Compiler Error:");
+      }
+      ImGui::Separator();
+      if (max_line_width + padding > max_workspace_width) {
+        ImGui::PushTextWrapPos(max_workspace_width - padding);
+        ImGui::TextUnformatted(load_error_.c_str());
+        ImGui::PopTextWrapPos();
+      } else {
+        ImGui::TextUnformatted(load_error_.c_str());
+      }
+    }
+    platform::EndOverlay();
+  }
+
   if (tmp_.info) {
     const float scale = ImGui::GetWindowDpiScale();
     if (platform::BeginOverlay("Info", platform::OverlayPos::kBottomLeft,
@@ -1890,9 +1934,6 @@ void App::StatusBarGui() {
     if (!step_error_.empty()) {
       ImGui::SameLine();
       ImGui::Text(" | Step Error: %s", step_error_.c_str());
-    } else if (!load_error_.empty()) {
-      ImGui::SameLine();
-      ImGui::Text(" | Load Error: %s", load_error_.c_str());
     } else if (!edit_error_.empty()) {
       ImGui::SameLine();
       ImGui::Text(" | Edit Error: %s", edit_error_.c_str());

src/experimental/studio/app.h

@@ -247,6 +247,8 @@ class App {
   std::string load_error_;
   std::string step_error_;
   std::string edit_error_;
+  platform::StepControl::PauseState last_pause_state_ =
+      platform::StepControl::PauseState::kNormalPaused;
 
   std::optional<std::string> pending_load_;
   std::function<void()> pending_op_;