Add defaults to SDF plugin attributes.

Expose diameter and number of teeth for the gear SDF.

PiperOrigin-RevId: 577779297
Change-Id: Iec5890ab7f39080b395cf06a76f9c2216f4f39ed

plugin/sdf/torus.cc

@@ -12,12 +12,14 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include <sstream>
+#include <cstdint>
 #include <optional>
+#include <utility>
 
 #include <mujoco/mjplugin.h>
 #include <mujoco/mjtnum.h>
 #include <mujoco/mujoco.h>
+#include "sdf.h"
 #include "torus.h"
 
 namespace mujoco::plugin::sdf {
@@ -43,19 +45,24 @@ std::optional<Torus> Torus::Create(
 
 // plugin constructor
 Torus::Torus(const mjModel* m, mjData* d, int instance) {
-  radius[0] = strtod(mj_getPluginConfig(m, instance, "radius1"), nullptr);
-  radius[1] = strtod(mj_getPluginConfig(m, instance, "radius2"), nullptr);
+  SdfDefault<TorusAttribute> defattribute;
+
+  for (int i=0; i < TorusAttribute::nattribute; i++) {
+    attribute[i] = defattribute.GetDefault(
+        TorusAttribute::names[i],
+        mj_getPluginConfig(m, instance, TorusAttribute::names[i]));
+  }
 }
 
 // sdf
 mjtNum Torus::Distance(const mjtNum point[3]) const {
-  return distance(point, radius);
+  return distance(point, attribute);
 }
 
 // gradient of sdf
 void Torus::Gradient(mjtNum grad[3], const mjtNum p[3]) const {
   mjtNum len_xy = mju_sqrt(p[0]*p[0] + p[1]*p[1]);
-  mjtNum q = len_xy - radius[0];
+  mjtNum q = len_xy - attribute[0];
   mjtNum grad_q[2] = { p[0] / len_xy, p[1] / len_xy };
   mjtNum len_qz = mju_sqrt(q*q + p[2]*p[2]);
   grad[0] = q*grad_q[0] / mjMAX(len_qz, mjMINVAL);
@@ -71,9 +78,8 @@ void Torus::RegisterPlugin() {
   plugin.name = "mujoco.sdf.torus";
   plugin.capabilityflags |= mjPLUGIN_SDF;
 
-  const char* attributes[] = {"radius1", "radius2", "axis"};
-  plugin.nattribute = sizeof(attributes) / sizeof(attributes[0]);
-  plugin.attributes = attributes;
+  plugin.nattribute = TorusAttribute::nattribute;
+  plugin.attributes = TorusAttribute::names;
   plugin.nstate = +[](const mjModel* m, int instance) { return 0; };
 
   plugin.init = +[](const mjModel* m, mjData* d, int instance) {
@@ -117,8 +123,13 @@ void Torus::RegisterPlugin() {
         aabb[3] = aabb[4] = attributes[0] + attributes[1];
         aabb[5] = attributes[1];
       };
+  plugin.sdf_attribute =
+      +[](mjtNum attribute[], const char* name[], const char* value[]) {
+        SdfDefault<TorusAttribute> defattribute;
+        defattribute.GetDefaults(attribute, name, value);
+      };
 
-      mjp_registerPlugin(&plugin);
+  mjp_registerPlugin(&plugin);
 }
 
 }  // namespace mujoco::plugin::sdf