Rename mjDSBL_AUTORESETNAN to mjDSBL_AUTORESET.

- Expose in MJCF.
- Add documentation.
- Improve handling in simulate.

PiperOrigin-RevId: 657606140
Change-Id: I6a27c2f4842d7d4ae32642f2a6255e5f8f1f605a

simulate/main.cc

@@ -199,6 +199,16 @@ void scanPluginLibraries() {
 
 //------------------------------------------- simulation -------------------------------------------
 
+const char* Diverged(int disableflags, const mjData* d) {
+  if (disableflags & mjDSBL_AUTORESET) {
+    for (mjtWarning w : {mjWARN_BADQACC, mjWARN_BADQVEL, mjWARN_BADQPOS}) {
+      if (d->warning[w].number > 0) {
+        return mju_warningText(w, d->warning[w].lastinfo);
+      }
+    }
+  }
+  return nullptr;
+}
 
 mjModel* LoadModel(const char* file, mj::Simulate& sim) {
   // this copy is needed so that the mju::strlen call below compiles
@@ -356,7 +366,13 @@ void PhysicsLoop(mj::Simulate& sim) {
 
             // run single step, let next iteration deal with timing
             mj_step(m, d);
-            stepped = true;
+            const char* message = Diverged(m->opt.disableflags, d);
+            if (message) {
+              sim.run = 0;
+              mju::strcpy_arr(sim.load_error, message);
+            } else {
+              stepped = true;
+            }
           }
 
           // in-sync: step until ahead of cpu
@@ -381,7 +397,13 @@ void PhysicsLoop(mj::Simulate& sim) {
 
               // call mj_step
               mj_step(m, d);
-              stepped = true;
+              const char* message = Diverged(m->opt.disableflags, d);
+              if (message) {
+                sim.run = 0;
+                mju::strcpy_arr(sim.load_error, message);
+              } else {
+                stepped = true;
+              }
 
               // break if reset
               if (d->time < prevSim) {

simulate/simulate.cc

@@ -739,18 +739,12 @@ void MakePhysicsSection(mj::Simulate* sim) {
   for (int i=0; i<mjNDISABLE; i++) {
     mju::strcpy_arr(defFlag[0].name, mjDISABLESTRING[i]);
     defFlag[0].pdata = sim->disable + i;
-    if ((1 << i) == mjDSBL_AUTORESETNAN) {
-      defFlag[0].state = 0;
-    } else {
-      defFlag[0].state = 2;
-    }
     mjui_add(&sim->ui0, defFlag);
   }
   mjui_add(&sim->ui0, defEnableFlags);
   for (int i=0; i<mjNENABLE; i++) {
     mju::strcpy_arr(defFlag[0].name, mjENABLESTRING[i]);
     defFlag[0].pdata = sim->enable + i;
-    defFlag[0].state = 2;
     mjui_add(&sim->ui0, defFlag);
   }
   // add contact override
@@ -1956,6 +1950,7 @@ void Simulate::Sync() {
   if (pending_.reset) {
     mj_resetData(m_, d_);
     mj_forward(m_, d_);
+    load_error[0] = '\0';
     update_profiler = true;
     update_sensor = true;
     scrub_index = 0;