set tessGeo when collecting custom vertex attributes

core/src/processing/opengl/PShapeOpenGL.java

@@ -2828,15 +2828,21 @@ public class PShapeOpenGL extends PShape {
 
   protected void tessellate() {
     if (root == this && parent == null) { // Root shape
+      boolean initAttr = false;
       if (polyAttribs == null) {
         polyAttribs = PGraphicsOpenGL.newAttributeMap();
-        collectPolyAttribs();
+        initAttr = true;
       }
 
       if (tessGeo == null) {
         tessGeo = PGraphicsOpenGL.newTessGeometry(pg, polyAttribs, PGraphicsOpenGL.RETAINED);
       }
       tessGeo.clear();
+
+      if (initAttr) {
+        collectPolyAttribs();
+      }
+
       for (int i = 0; i < polyAttribs.size(); i++) {
         VertexAttribute attrib = polyAttribs.get(i);
         tessGeo.initAttrib(attrib);
@@ -2854,6 +2860,7 @@ public class PShapeOpenGL extends PShape {
 
   protected void collectPolyAttribs() {
     AttributeMap rootAttribs = root.polyAttribs;
+    tessGeo = root.tessGeo;
 
     if (family == GROUP) {
       for (int i = 0; i < childCount; i++) {