Dynamic model editing.

PiperOrigin-RevId: 640838852
Change-Id: I559b1d60f2a3a2d866788d4006be31757454c619

src/engine/engine_io.c

@@ -1093,7 +1093,7 @@ static void mj_setPtrData(const mjModel* m, mjData* d) {
 
 
 // initialize plugins, copy into d (required for deletion)
-static void _initPlugin(const mjModel* m, mjData* d) {
+void mj_initPlugin(const mjModel* m, mjData* d) {
   d->nplugin = m->nplugin;
   for (int i = 0; i < m->nplugin; ++i) {
     d->plugin[i] = m->plugin[i];
@@ -1203,7 +1203,7 @@ mjData* mj_makeData(const mjModel* m) {
   mjData* d = NULL;
   mj_makeRawData(&d, m);
   if (d) {
-    _initPlugin(m, d);
+    mj_initPlugin(m, d);
     mj_resetData(m, d);
   }
   return d;
@@ -1219,7 +1219,7 @@ mjData* mj_copyData(mjData* dest, const mjModel* m, const mjData* src) {
   // allocate new data if needed
   if (!dest) {
     mj_makeRawData(&dest, m);
-    _initPlugin(m, dest);
+    mj_initPlugin(m, dest);
   }
 
   // check sizes

src/engine/engine_io.h

@@ -110,6 +110,9 @@ MJAPI void mj_resetDataKeyframe(const mjModel* m, mjData* d, int key);
 // mjData arena allocate
 MJAPI void* mj_arenaAllocByte(mjData* d, size_t bytes, size_t alignment);
 
+// init plugins
+MJAPI void mj_initPlugin(const mjModel* m, mjData* d);
+
 #ifndef ADDRESS_SANITIZER
 
 // mjData mark stack frame