1 files changed, 1 insertions, 1 deletions
diff --git a/progs/trivial/tri-blend.c b/progs/trivial/tri-blend.c
index 284d15fd3c..58c451c976 100644
--- a/progs/trivial/tri-blend.c
+++ b/progs/trivial/tri-blend.c
@@ -132,7 +132,7 @@ void keyboard(unsigned char key, int x, int y)
 int main(int argc, char** argv)
 {
    glutInit(&argc, argv);
-   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
+   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_ALPHA);
    glutInitWindowSize (200, 200);
    glutCreateWindow (argv[0]);
    init();