1 files changed, 2 insertions, 0 deletions
diff --git a/progs/glsl/twoside.c b/progs/glsl/twoside.c
index 06488bd1759..9ebc4ec3607 100644
--- a/progs/glsl/twoside.c
+++ b/progs/glsl/twoside.c
@@ -12,6 +12,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>
+#include <GL/glew.h>
 #include <GL/gl.h>
 #include <GL/glut.h>
 #include <GL/glext.h>
@@ -293,6 +294,7 @@ main(int argc, char *argv[])
    glutInitWindowSize(WinWidth, WinHeight);
    glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
    win = glutCreateWindow(argv[0]);
+   glewInit();
    glutReshapeFunc(Reshape);
    glutKeyboardFunc(Key);
    glutDisplayFunc(Redisplay);