diff --git a/render/GlutRender.cpp b/render/GlutRender.cpp
index 28a4d74..fdc4fae 100644
--- a/render/GlutRender.cpp
+++ b/render/GlutRender.cpp
@@ -17,7 +17,7 @@ void GlutRender::init(int* argc, char** argv,
         int wid, int hei, const char* win_name)
 {
    glutInit(argc, argv);
-   glutInitDisplayMode(GLUT_DOUBLE);
+   glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH);
    glutInitWindowSize(wid, hei);
    glutCreateWindow(win_name);