Make change non-breaking per haroonq's feedback

src/render/classic/render_context.c

@@ -14,6 +14,7 @@
 
 #include "render/classic/render_context.h"
 
+#include <inttypes.h>  // IWYU pragma: keep
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -1298,6 +1299,44 @@ static void makeFont(mjrContext* con, int fontscale) {
   }
 }
 
+// make materials, just for those that have textures
+static void makeMaterial(const mjModel* m, mjrContext* con) {
+  memset(con->mat_texid, -1, sizeof(con->mat_texid));
+  memset(con->mat_texuniform, 0, sizeof(con->mat_texuniform));
+  memset(con->mat_texrepeat, 0, sizeof(con->mat_texrepeat));
+
+  // find skybox texture
+  for (int i=0; i < m->ntex; i++) {
+    if (m->tex_type[i] == mjTEXTURE_SKYBOX) {
+      if (m->nmat >= mjMAXMATERIAL-2) {
+        mju_error("With skybox, maximum number of materials is %d, got %" PRId64,
+                  mjMAXMATERIAL-1, m->nmat);
+      }
+      for (int j=0; j < mjNTEXROLE; j++) {
+        con->mat_texid[mjNTEXROLE * (mjMAXMATERIAL-1) + j] = -1;
+      }
+      con->mat_texid[mjNTEXROLE * (mjMAXMATERIAL-1) + mjTEXROLE_RGB] = i;
+
+      break;
+    }
+  }
+
+  if (m->nmat >= mjMAXMATERIAL-1) {
+    mju_error("Maximum number of materials is %d, got %" PRId64, mjMAXMATERIAL, m->nmat);
+  }
+  for (int i=0; i < m->nmat; i++) {
+    if (m->mat_texid[i*mjNTEXROLE + mjTEXROLE_RGB] >= 0) {
+      for (int j=0; j < mjNTEXROLE; j++) {
+        con->mat_texid[i*mjNTEXROLE + j] = m->mat_texid[i*mjNTEXROLE + 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];
+    }
+  }
+}
+
+
 // make textures
 static void makeTexture(const mjModel* m, mjrContext* con) {
   // checks size
@@ -1600,6 +1639,7 @@ void mjr_makeContext_offSize(const mjModel* m, mjrContext* con, int fontscale,
   // make everything
   makeOff(con);
   makeShadow(m, con);
+  makeMaterial(m, con);
   makeTexture(m, con);
   makePlane(m, con);
   makeMesh(m, con);

src/render/classic/render_gl3.c

@@ -61,10 +61,19 @@ enum {
 // enable/disable texture mapping
 static void settexture(int type, int state, const mjrContext* con, const mjvGeom* geom) {
   float plane[4], scl[2];
-  int texid = -1;
+  int texid = -1, texuniform = 0;
+  float texrepeat[2] = {0, 0};
   if (geom) {
-    if (geom->matid >= 0) {
+    if (geom->texid >= 0) {
       texid = geom->texid;
+      texuniform = geom->texuniform;
+      texrepeat[0] = geom->texrepeat[0];
+      texrepeat[1] = geom->texrepeat[1];
+    } else if (geom->matid >= 0) {
+      texid = con->mat_texid[mjNTEXROLE * geom->matid + mjTEXROLE_RGB];
+      texuniform = con->mat_texuniform[geom->matid];
+      texrepeat[0] = con->mat_texrepeat[geom->matid*2];
+      texrepeat[1] = con->mat_texrepeat[geom->matid*2+1];
     }
   }
 
@@ -119,8 +128,8 @@ static void settexture(int type, int state, const mjrContext* con, const mjvGeom
       glBindTexture(GL_TEXTURE_2D, con->texture[texid]);
 
       // determine scaling, adjust for pre-scaled geoms
-      scl[0] = geom->texrepeat[0];
-      scl[1] = geom->texrepeat[1];
+      scl[0] = texrepeat[0];
+      scl[1] = texrepeat[1];
       if (geom->dataid >= 0) {
         if (geom->size[0] > 0) {
           scl[0] = scl[0] / mju_max(mjMINVAL, geom->size[0]);
@@ -132,7 +141,7 @@ static void settexture(int type, int state, const mjrContext* con, const mjvGeom
       }
 
       // uniform: repeat relative to spatial units rather than object
-      if (geom->texuniform) {
+      if (texuniform) {
         if (geom->size[0] > 0) {
           scl[0] = scl[0] * geom->size[0];
         }
@@ -171,11 +180,11 @@ static void settexture(int type, int state, const mjrContext* con, const mjvGeom
 
       // set mapping : cube
       if (type == mjtexREGULAR) {
-        mjr_setf4(plane, geom->texuniform ? geom->size[0] : 1, 0, 0, 0);
+        mjr_setf4(plane, texuniform ? geom->size[0] : 1, 0, 0, 0);
         glTexGenfv(GL_S, GL_OBJECT_PLANE, plane);
-        mjr_setf4(plane, 0, geom->texuniform ? geom->size[1] : 1, 0, 0);
+        mjr_setf4(plane, 0, texuniform ? geom->size[1] : 1, 0, 0);
         glTexGenfv(GL_T, GL_OBJECT_PLANE, plane);
-        mjr_setf4(plane, 0, 0, geom->texuniform ? geom->size[2] : 1, 0);
+        mjr_setf4(plane, 0, 0, texuniform ? geom->size[2] : 1, 0);
         glTexGenfv(GL_R, GL_OBJECT_PLANE, plane);
       }