check if attribute is active

core/src/processing/opengl/PGraphicsOpenGL.java

@@ -2586,6 +2586,7 @@ public class PGraphicsOpenGL extends PGraphics {
         }
 
         for (VertexAttribute attrib: polyAttribs.values()) {
+          if (!attrib.active()) continue;
           attrib.updateLoc(shader);
           attrib.bind(pgl);
           shader.setAttributeVBO(attrib.glLoc, attrib.glName,
@@ -2596,7 +2597,10 @@ public class PGraphicsOpenGL extends PGraphics {
         shader.draw(glPolyIndex, icount, ioffset);
       }
 
-      for (VertexAttribute attrib: polyAttribs.values()) attrib.unbind(pgl);
+      for (VertexAttribute attrib: polyAttribs.values()) {
+        if (!attrib.active()) continue;
+        attrib.unbind(pgl);
+      }
       shader.unbind();
     }
     unbindPolyBuffers();
@@ -7137,6 +7141,10 @@ public class PGraphicsOpenGL extends PGraphics {
       pgl.disableVertexAttribArray(glLoc);
     }
 
+    boolean active() {
+      return -1 < glLoc;
+    }
+
     void updateLoc(PShader shader) {
       if (glLoc == -1) glLoc = shader.getAttributeLoc(name);
     }

core/src/processing/opengl/PShapeOpenGL.java

@@ -4903,6 +4903,7 @@ public class PShapeOpenGL extends PShape {
       }
 
       for (VertexAttribute attrib: polyAttribs.values()) {
+        if (!attrib.active()) continue;
         attrib.updateLoc(shader);
         attrib.bind(pgl);
         shader.setAttributeVBO(attrib.glLoc, attrib.glName,
@@ -4913,8 +4914,13 @@ public class PShapeOpenGL extends PShape {
       shader.draw(root.glPolyIndex, icount, ioffset);
     }
 
-    for (VertexAttribute attrib: polyAttribs.values()) attrib.unbind(pgl);
-    if (shader != null && shader.bound()) shader.unbind();
+    for (VertexAttribute attrib: polyAttribs.values()) {
+      if (!attrib.active()) continue;
+      attrib.unbind(pgl);
+    }
+    if (shader != null && shader.bound()) {
+      shader.unbind();
+    }
   }