diff --git a/core/src/processing/core/PShape.java b/core/src/processing/core/PShape.java
index 768553079..a9b28eaa9 100644
--- a/core/src/processing/core/PShape.java
+++ b/core/src/processing/core/PShape.java
@@ -115,6 +115,9 @@ public class PShape implements PConstants {
   static public final String NO_VERTICES_ERROR =
     "getVertexCount() only works with PATH or GEOMETRY shapes";
 
+  public static final String NOT_A_SIMPLE_VERTEX =
+      "%1$s can not be called on quadratic or bezier vertices";
+
   // boundary box of this shape
   //protected float x;
   //protected float y;
diff --git a/core/src/processing/opengl/PShapeOpenGL.java b/core/src/processing/opengl/PShapeOpenGL.java
index 3ddead7ce..6cfdb1008 100644
--- a/core/src/processing/opengl/PShapeOpenGL.java
+++ b/core/src/processing/opengl/PShapeOpenGL.java
@@ -1708,14 +1708,25 @@ public class PShapeOpenGL extends PShape {
       return;
     }
 
+    if (vertexCodes[index] != VERTEX) {
+      PGraphics.showWarning(NOT_A_SIMPLE_VERTEX, "setVertex()");
+      return;
+    }
+
     // TODO: in certain cases (kind = TRIANGLE, etc) the correspondence between
     // input and tessellated vertices is 1-1, so in those cases re-tessellation
     // wouldn't be necessary. But in order to reasonable take care of that
     // situation, we would need a complete rethinking of the rendering architecture
     // in Processing :-)
-    inGeo.vertices[3 * index + 0] = x;
-    inGeo.vertices[3 * index + 1] = y;
-    inGeo.vertices[3 * index + 2] = z;
+    if (family == PATH) {
+      vertices[index][X] = x;
+      vertices[index][Y] = y;
+      if (is3D) vertices[index][Z] = z;
+    } else {
+      inGeo.vertices[3 * index + 0] = x;
+      inGeo.vertices[3 * index + 1] = y;
+      inGeo.vertices[3 * index + 2] = z;
+    }
     markForTessellation();
   }