Add metallic and roughness scalar attributes to materials.

Rename `light_radius` -> `light_bulbradius`, make the default value 0.02.

PiperOrigin-RevId: 627032170
Change-Id: I1e01e2eca028c0aefc2e7dc384e8b34abac184aa

src/user/user_api.h

@@ -347,7 +347,6 @@ typedef struct _mjsLight {         // light specification
   // frame
   double pos[3];                   // position
   double dir[3];                   // direction
-  double radius;                   // radius
   mjtCamLight mode;                // tracking mode
   mjString targetbody;             // target body for targeting
 
@@ -355,6 +354,7 @@ typedef struct _mjsLight {         // light specification
   mjtByte active;                  // is light active
   mjtByte directional;             // is light directional or spot
   mjtByte castshadow;              // does light cast shadows
+  double bulbradius;               // bulb radius, for soft shadows
   float attenuation[3];            // OpenGL attenuation (quadratic model)
   float cutoff;                    // OpenGL cutoff
   float exponent;                  // OpenGL exponent
@@ -515,6 +515,8 @@ typedef struct _mjsMaterial {      // material specification
   float specular;                  // specular
   float shininess;                 // shininess
   float reflectance;               // reflectance
+  float metallic;                  // metallic
+  float roughness;                 // roughness
   float rgba[4];                   // rgba
   mjString info;                   // message appended to compiler errors
 } mjsMaterial;

src/user/user_init.cc

@@ -218,6 +218,7 @@ void mjs_defaultLight(mjsLight& light) {
 
   // intrinsics
   light.castshadow = 1;
+  light.bulbradius = 0.02;
   light.active = 1;
   light.dir[2] = -1;
   light.attenuation[0] = 1;
@@ -305,6 +306,8 @@ void mjs_defaultMaterial(mjsMaterial& material) {
   material.specular = 0.5;
   material.shininess = 0.5;
   material.reflectance = 0;
+  material.metallic = 1.0;
+  material.roughness = 1.0;
   material.rgba[0] = material.rgba[1] = material.rgba[2] = material.rgba[3] = 1;
 }
 

src/user/user_model.cc

@@ -2070,7 +2070,7 @@ void mjCModel::CopyTree(mjModel* m) {
       m->light_active[lid] = (mjtByte)pl->active;
       copyvec(m->light_pos+3*lid, pl->pos, 3);
       copyvec(m->light_dir+3*lid, pl->dir, 3);
-      m->light_radius[lid] = pl->radius;
+      m->light_bulbradius[lid] = pl->bulbradius;
       copyvec(m->light_attenuation+3*lid, pl->attenuation, 3);
       m->light_cutoff[lid] = pl->cutoff;
       m->light_exponent[lid] = pl->exponent;
@@ -2487,6 +2487,8 @@ void mjCModel::CopyObjects(mjModel* m) {
     m->mat_specular[i] = pmat->specular;
     m->mat_shininess[i] = pmat->shininess;
     m->mat_reflectance[i] = pmat->reflectance;
+    m->mat_metallic[i] = pmat->metallic;
+    m->mat_roughness[i] = pmat->roughness;
     copyvec(m->mat_rgba+4*i, pmat->rgba, 4);
   }