Move texture block copy out of render context so it can be modified online via mjmodel

Author: bd-pmorais

doc/APIreference/APIglobals.rst

@@ -583,9 +583,6 @@ Defined in `mjrender.h <https://github.com/google-deepmind/mujoco/blob/main/incl
    * - ``mjMAXTEXTURE``
      - 1000
      - Maximum number of textures allowed.
-   * - ``mjMAXMATERIAL``
-     - 1000
-     - Maximum number of materials with textures.
 
 
 .. _glNumericUI:

doc/changelog.rst

@@ -32,6 +32,15 @@ General
      exclusively in the compressed sparse row (CSR) format ``mjData.M``.
    - :ref:`mju_round` now breaks ties away from zero rather than towards :math:`+\infty`. This only affects
      negative half-integers, e.g. ``mju_round(-2.5)`` now returns -3 rather than -2.
+   - Removed the ``mjMAXMATERIAL`` constant. The classic renderer no longer caps the number of textured materials.
+
+.. admonition:: Breaking ABI changes
+   :class: attention
+
+   - Removed ``mat_texid``, ``mat_texuniform`` and ``mat_texrepeat`` from ``mjrContext``; the equivalent per-geom fields
+     ``texid``, ``texuniform`` and ``texrepeat`` were added to ``mjvGeom``, populated from the model each frame by
+     :ref:`mjv_updateScene`. The classic renderer now resolves them live, so runtime material changes (e.g. domain
+     randomization) no longer require rebuilding the render context.
 
 Version 3.10.0 (June 22, 2026)
 ------------------------------

include/mujoco/mjrender.h

@@ -24,7 +24,6 @@ extern "C" {
 
 #define mjNAUX          10        // number of auxiliary buffers
 #define mjMAXTEXTURE    1000      // maximum number of textures
-#define mjMAXMATERIAL   1000      // maximum number of materials with textures
 
 //---------------------------------- primitive types (mjt) -----------------------------------------
 
@@ -170,11 +169,6 @@ typedef struct mjrContext_ {        // custom OpenGL context
   unsigned int auxColor[mjNAUX];    // auxiliary color buffer
   unsigned int auxColor_r[mjNAUX];  // auxiliary color buffer for resolving
 
-  // materials with textures
-  int mat_texid[mjMAXMATERIAL*mjNTEXROLE]; // material texture ids (-1: no texture)
-  int mat_texuniform[mjMAXMATERIAL];       // uniform cube mapping
-  float mat_texrepeat[mjMAXMATERIAL*2];    // texture repetition for 2d mapping
-
   // texture objects and info
   int ntexture;                            // number of allocated textures
   int textureType[mjMAXTEXTURE];           // type of texture (mjtTexture) (ntexture)

include/mujoco/mjvisualize.h

@@ -229,6 +229,8 @@ typedef struct mjvGeom_ {         // abstract geom
   int      objid;                 // mujoco object id; -1 for decor
   int      category;              // visual category
   int      matid;                 // material id; -1: no textured material
+  int      texid;                 // texture id; -1: none
+  int      texuniform;            // uniform cube mapping
   int      texcoord;              // mesh or flex geom has texture coordinates
   int      segid;                 // segmentation id; -1: not shown
 
@@ -243,6 +245,7 @@ typedef struct mjvGeom_ {         // abstract geom
   float    specular;              // specular coef
   float    shininess;             // shininess coef
   float    reflectance;           // reflectance coef
+  float    texrepeat[2];          // texture repetition for 2d mapping
 
   char     label[100];            // text label
 

python/mujoco/introspect/structs.py

@@ -10140,6 +10140,16 @@
                  type=ValueType(name='int'),
                  doc='material id; -1: no textured material',
              ),
+             StructFieldDecl(
+                 name='texid',
+                 type=ValueType(name='int'),
+                 doc='texture id; -1: none',
+             ),
+             StructFieldDecl(
+                 name='texuniform',
+                 type=ValueType(name='int'),
+                 doc='uniform cube mapping',
+             ),
              StructFieldDecl(
                  name='texcoord',
                  type=ValueType(name='int'),
@@ -10202,6 +10212,14 @@
                  type=ValueType(name='float'),
                  doc='reflectance coef',
              ),
+             StructFieldDecl(
+                 name='texrepeat',
+                 type=ArrayType(
+                     inner_type=ValueType(name='float'),
+                     extents=(2,),
+                 ),
+                 doc='texture repetition for 2d mapping',
+             ),
              StructFieldDecl(
                  name='label',
                  type=ArrayType(
@@ -11178,30 +11196,6 @@
                  ),
                  doc='auxiliary color buffer for resolving',
              ),
-             StructFieldDecl(
-                 name='mat_texid',
-                 type=ArrayType(
-                     inner_type=ValueType(name='int'),
-                     extents=(10000,),
-                 ),
-                 doc='material texture ids (-1: no texture)',
-             ),
-             StructFieldDecl(
-                 name='mat_texuniform',
-                 type=ArrayType(
-                     inner_type=ValueType(name='int'),
-                     extents=(1000,),
-                 ),
-                 doc='uniform cube mapping',
-             ),
-             StructFieldDecl(
-                 name='mat_texrepeat',
-                 type=ArrayType(
-                     inner_type=ValueType(name='float'),
-                     extents=(2000,),
-                 ),
-                 doc='texture repetition for 2d mapping',
-             ),
              StructFieldDecl(
                  name='ntexture',
                  type=ValueType(name='int'),

python/mujoco/render.cc

@@ -54,9 +54,6 @@ class MjWrapper<raw::MjrContext> : public WrapperBase<raw::MjrContext> {
   X(auxFBO_r);
   X(auxColor);
   X(auxColor_r);
-  X(mat_texid);
-  X(mat_texuniform);
-  X(mat_texrepeat);
   X(textureType);
   X(texture);
   X(skinvertVBO);
@@ -98,9 +95,6 @@ MjrContextWrapper::MjWrapper()
       X(auxFBO_r),
       X(auxColor),
       X(auxColor_r),
-      X(mat_texid),
-      X(mat_texuniform),
-      X(mat_texrepeat),
       X(textureType),
       X(texture),
       X_SKIN(skinvertVBO),
@@ -125,9 +119,6 @@ MjrContextWrapper::MjWrapper(const MjModelWrapper& model, int fontscale)
       X(auxFBO_r),
       X(auxColor),
       X(auxColor_r),
-      X(mat_texid),
-      X(mat_texuniform),
-      X(mat_texrepeat),
       X(textureType),
       X(texture),
       X_SKIN(skinvertVBO),
@@ -228,9 +219,6 @@ PYBIND11_MODULE(_render, pymodule, pybind11::mod_gil_not_used()) {
   X(auxFBO_r);
   X(auxColor);
   X(auxColor_r);
-  X(mat_texid);
-  X(mat_texuniform);
-  X(mat_texrepeat);
   X(textureType);
   X(texture);
   X(skinvertVBO);

python/mujoco/structs.cc

@@ -1185,6 +1185,8 @@ This is useful for example when the MJB is not available as a file on disk.)"));
   X(objid);
   X(category);
   X(matid);
+  X(texid);
+  X(texuniform);
   X(texcoord);
   X(segid);
   X(emission);
@@ -1201,6 +1203,7 @@ This is useful for example when the MJB is not available as a file on disk.)"));
   X(pos);
   X(mat);
   X(rgba);
+  X(texrepeat);
 #undef X
 
   DefinePyStr(mjvGeom, "label", &raw::MjvGeom::label);

python/mujoco/structs.h

@@ -832,6 +832,7 @@ class MjWrapper<raw::MjvGeom> : public WrapperBase<raw::MjvGeom> {
   X(pos);
   X(mat);
   X(rgba);
+  X(texrepeat);
   #undef X
 };
 

python/mujoco/structs_wrappers.cc

@@ -1193,7 +1193,8 @@ MjvGeomWrapper::MjWrapper()
         static_assert(sizeof(ptr_->mat) == sizeof(ptr_->mat[0]) * 9);
         return InitPyArray(std::array{3, 3}, ptr_->mat, owner_);
       }()),
-      X(rgba) {
+      X(rgba),
+      X(texrepeat) {
   mjv_initGeom(ptr_, mjGEOM_NONE, nullptr, nullptr, nullptr, nullptr);
 }
 
@@ -1205,7 +1206,8 @@ MjvGeomWrapper::MjWrapper(raw::MjvGeom* ptr, py::handle owner)
         static_assert(sizeof(ptr_->mat) == sizeof(ptr_->mat[0]) * 9);
         return InitPyArray(std::array{3, 3}, ptr_->mat, owner_);
       }()),
-      X(rgba) {}
+      X(rgba),
+      X(texrepeat) {}
 #undef X
 
 MjvGeomWrapper::MjWrapper(const MjvGeomWrapper& other) : MjvGeomWrapper() {

src/engine/engine_vis_visualize.c

@@ -241,6 +241,10 @@ static void setMaterial(const mjModel* m, mjvGeom* geom, int matid, const float*
   // set texture
   if (flags[mjVIS_TEXTURE] && matid >= 0) {
     geom->matid = matid;
+    geom->texid = m->mat_texid[matid*mjNTEXROLE + mjTEXROLE_RGB];
+    geom->texuniform = m->mat_texuniform[matid];
+    geom->texrepeat[0] = m->mat_texrepeat[2*matid];
+    geom->texrepeat[1] = m->mat_texrepeat[2*matid+1];
   }
 
   // scale alpha for dynamic geoms only
@@ -379,6 +383,10 @@ void mjv_initGeom(mjvGeom* geom, int type, const mjtNum* size,
   // set defaults that cannot be assigned via this function
   geom->dataid       = -1;
   geom->matid        = -1;
+  geom->texid        = -1;
+  geom->texuniform   = 0;
+  geom->texrepeat[0] = 0;
+  geom->texrepeat[1] = 0;
   geom->texcoord     = 0;
   geom->emission     = 0;
   geom->specular     = 0.5;