Add support for multiple textures in one material (mjModel).

PiperOrigin-RevId: 648732764
Change-Id: I29b60dd62a069789a32017ff0d55e36b57e0052b

doc/includes/references.h

@@ -1220,7 +1220,7 @@ struct mjModel_ {
   int*      tex_pathadr;          // address of texture asset path; -1: none  (ntex x 1)
 
   // materials
-  int*      mat_texid;            // texture id; -1: none                     (nmat x 1)
+  int*      mat_texid;            // indices of textures; -1: none            (nmat x mjNTEXMAT)
   mjtByte*  mat_texuniform;       // make texture cube uniform                (nmat x 1)
   float*    mat_texrepeat;        // texture repetition for 2d mapping        (nmat x 2)
   float*    mat_emission;         // emission (x rgb)                         (nmat x 1)
@@ -2792,7 +2792,7 @@ struct mjvFigure_ {               // abstract 2D figure passed to OpenGL rendere
 
   // line data
   int     linepnt[mjMAXLINE];     // number of points in line; (0) disable
-  float   linedata[mjMAXLINE][2*mjMAXLINEPNT]; // line data (x,y)
+  float   linedata[mjMAXLINE][2*mjMAXLINEPNT];  // line data (x,y)
 
   // output from renderer
   int     xaxispixel[2];          // range of x-axis in pixels

include/mujoco/mjmodel.h

@@ -935,7 +935,7 @@ struct mjModel_ {
   int*      tex_pathadr;          // address of texture asset path; -1: none  (ntex x 1)
 
   // materials
-  int*      mat_texid;            // texture id; -1: none                     (nmat x 1)
+  int*      mat_texid;            // indices of textures; -1: none            (nmat x mjNTEXMAT)
   mjtByte*  mat_texuniform;       // make texture cube uniform                (nmat x 1)
   float*    mat_texrepeat;        // texture repetition for 2d mapping        (nmat x 2)
   float*    mat_emission;         // emission (x rgb)                         (nmat x 1)

include/mujoco/mjvisualize.h

@@ -394,7 +394,7 @@ struct mjvFigure_ {               // abstract 2D figure passed to OpenGL rendere
 
   // line data
   int     linepnt[mjMAXLINE];     // number of points in line; (0) disable
-  float   linedata[mjMAXLINE][2*mjMAXLINEPNT]; // line data (x,y)
+  float   linedata[mjMAXLINE][2*mjMAXLINEPNT];  // line data (x,y)
 
   // output from renderer
   int     xaxispixel[2];          // range of x-axis in pixels

include/mujoco/mjxmacro.h

@@ -413,7 +413,7 @@
     X   ( int,     tex_adr,               ntex,          1                    ) \
     X   ( mjtByte, tex_rgb,               ntexdata,      1                    ) \
     XMJV( int,     tex_pathadr,           ntex,          1                    ) \
-    XMJV( int,     mat_texid,             nmat,          1                    ) \
+    XMJV( int,     mat_texid,             nmat,          mjNTEXMAT            ) \
     XMJV( mjtByte, mat_texuniform,        nmat,          1                    ) \
     XMJV( float,   mat_texrepeat,         nmat,          2                    ) \
     XMJV( float,   mat_emission,          nmat,          1                    ) \

introspect/structs.py

@@ -2950,7 +2950,7 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                  type=PointerType(
                      inner_type=ValueType(name='int'),
                  ),
-                 doc='texture id; -1: none                     (nmat x 1)',
+                 doc='indices of textures; -1: none            (nmat x mjNTEXMAT)',  # pylint: disable=line-too-long
              ),
              StructFieldDecl(
                  name='mat_texuniform',

python/mujoco/indexer_xmacro.h

@@ -168,7 +168,7 @@
   X( float,   light_, specular,      nlight,  3 )
 
 #define MJMODEL_MATERIAL                   \
-  X( int,     mat_, texid,       nmat, 1 ) \
+  X( int,     mat_, texid,       nmat, mjNTEXMAT ) \
   X( mjtByte, mat_, texuniform,  nmat, 1 ) \
   X( float,   mat_, texrepeat,   nmat, 2 ) \
   X( float,   mat_, emission,    nmat, 1 ) \

python/mujoco/usd/exporter.py

@@ -233,7 +233,7 @@ class USDExporter:
     assert geom_name not in self.geom_name2usd
 
     texture_file = (
-        self.texture_files[self.model.mat_texid[geom.matid]]
+        self.texture_files[self.model.mat_texid[mujoco.mjNTEXMAT*geom.matid]]
         if geom.matid != -1
         else None
     )

src/render/render_context.c

@@ -1307,8 +1307,10 @@ static void makeMaterial(const mjModel* m, mjrContext* con) {
     mju_error("Maximum number of materials is %d", mjMAXMATERIAL);
   }
   for (int i=0; i < m->nmat; i++) {
-    if (m->mat_texid[i] >= 0) {
-      con->mat_texid[i*mjNTEXMAT] = m->mat_texid[i];
+    if (m->mat_texid[i*mjNTEXMAT] >= 0) {
+      for (int j=0; j < mjNTEXMAT; j++) {
+        con->mat_texid[i*mjNTEXMAT + j] = m->mat_texid[i*mjNTEXMAT + j];
+      }
       con->mat_texuniform[i] = m->mat_texuniform[i];
       con->mat_texrepeat[2*i] = m->mat_texrepeat[2*i];
       con->mat_texrepeat[2*i+1] = m->mat_texrepeat[2*i+1];
@@ -1321,6 +1323,10 @@ static void makeMaterial(const mjModel* m, mjrContext* con) {
         mju_error("With skybox, maximum number of materials is %d", mjMAXMATERIAL);
       }
       con->mat_texid[mjNTEXMAT * (mjMAXMATERIAL-1)] = i;
+      for (int j=1; j < mjNTEXMAT; j++) {
+        con->mat_texid[mjNTEXMAT * (mjMAXMATERIAL-1) + j] = -1;
+      }
+
       break;
     }
   }

src/user/user_model.cc

@@ -2481,7 +2481,10 @@ void mjCModel::CopyObjects(mjModel* m) {
     mjCMaterial* pmat = materials_[i];
 
     // set fields
-    m->mat_texid[i] = pmat->texid;
+    m->mat_texid[mjNTEXMAT*i] = pmat->texid;
+    for (int j=1; j<mjNTEXMAT; j++) {
+      m->mat_texid[mjNTEXMAT*i+j] = -1;
+    }
     m->mat_texuniform[i] = pmat->texuniform;
     mjuu_copyvec(m->mat_texrepeat+2*i, pmat->texrepeat, 2);
     m->mat_emission[i] = pmat->emission;