diff --git a/util/test/demos/gl/gl_mesh_zoo.cpp b/util/test/demos/gl/gl_mesh_zoo.cpp
index 38f2cc6b0..cd6480996 100644
--- a/util/test/demos/gl/gl_mesh_zoo.cpp
+++ b/util/test/demos/gl/gl_mesh_zoo.cpp
@@ -323,7 +323,7 @@ void main()
       glBufferSubData(GL_DRAW_INDIRECT_BUFFER, sizeof(cmd), sizeof(cmd), &cmd);
       glBufferSubData(GL_PARAMETER_BUFFER, 0, sizeof(count), &count);
 
-      glMultiDrawElementsIndirectCount(GL_TRIANGLES, GL_UNSIGNED_INT, NULL, NULL, 4,
+      glMultiDrawElementsIndirectCount(GL_TRIANGLES, GL_UNSIGNED_INT, NULL, (GLintptr)0, 4,
                                        sizeof(DrawElementsIndirectCommand));
 
       glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo);
diff --git a/util/test/demos/gl/gl_test_linux.cpp b/util/test/demos/gl/gl_test_linux.cpp
index ba8b5fc91..11b2c1761 100644
--- a/util/test/demos/gl/gl_test_linux.cpp
+++ b/util/test/demos/gl/gl_test_linux.cpp
@@ -230,7 +230,7 @@ void OpenGLGraphicsTest::ActivateContext(GraphicsWindow *win, void *ctx)
 
   if(ctx == NULL)
   {
-    glXMakeContextCurrent(x11win->xlib.display, NULL, NULL, NULL);
+    glXMakeContextCurrent(x11win->xlib.display, (GLXDrawable)NULL, (GLXDrawable)NULL, NULL);
     return;
   }