Update Solid and Shell plugins to use FlexComp.

PiperOrigin-RevId: 573755821
Change-Id: I3b8d7fb27f0e940038fa9fd2b26ecc746df4f7ac

src/engine/engine_collision_driver.c

@@ -1814,6 +1814,8 @@ void mj_collideFlexSAP(const mjModel* m, mjData* d, int f) {
 
 // test a geom and an elem for collision, add to contact list
 void mj_collideGeomElem(const mjModel* m, mjData* d, int g, int f, int e) {
+  TM_START;
+
   mjtNum margin = mj_assignMargin(m, mju_max(m->geom_margin[g], m->flex_margin[f]));
   int dim = m->flex_dim[f], type = m->geom_type[g];
   int num;
@@ -1927,6 +1929,9 @@ void mj_collideGeomElem(const mjModel* m, mjData* d, int g, int f, int e) {
 
   // move arena pointer back to the end of the contact array
   resetArena(d);
+
+  // add duration without incrementing counter
+  TM_ADD(mjTIMER_COL_NARROW);
 }
 
 
@@ -1934,6 +1939,7 @@ void mj_collideGeomElem(const mjModel* m, mjData* d, int g, int f, int e) {
 // test two elems for collision, add to contact list
 void mj_collideElems(const mjModel* m, mjData* d, int f1, int e1, int f2, int e2) {
   TM_START;
+
   mjtNum margin = mj_assignMargin(m, mju_max(m->flex_margin[f1], m->flex_margin[f2]));
   int dim1 = m->flex_dim[f1], dim2 = m->flex_dim[f2];
   int num;

src/engine/engine_core_smooth.c

@@ -537,9 +537,7 @@ void mj_flex(const mjModel* m, mjData* d) {
   // compute lengths and Jacobians of edges
   for (int f=0; f < m->nflex; f++) {
     // skip if edges cannot generate forces
-    if (m->flex_rigid[f] ||
-        (m->flex_edgeequality[f] == 0 &&
-         m->flex_edgestiffness[f] == 0 && m->flex_edgedamping[f] == 0)) {
+    if (m->flex_rigid[f]) {
       continue;
     }
 

src/engine/engine_sensor.c

@@ -948,11 +948,11 @@ void mj_energyPos(const mjModel* m, mjData* d) {
     }
   }
 
-  // add flex-level springs
+  // add flex-level springs for dim=1 (dim>1 requires plugins)
   if (!mjDISABLED(mjDSBL_PASSIVE)) {
     for (int i=0; i < m->nflex; i++) {
       stiffness = m->flex_edgestiffness[i];
-      if (m->flex_rigid[i] || stiffness == 0) {
+      if (m->flex_rigid[i] || stiffness == 0 || m->flex_dim[i] > 1) {
         continue;
       }