diff --git a/libc3/window/sdl2/demo/window_sdl2_demo.c b/libc3/window/sdl2/demo/window_sdl2_demo.c
index e5668e4..91ce296 100644
--- a/libc3/window/sdl2/demo/window_sdl2_demo.c
+++ b/libc3/window/sdl2/demo/window_sdl2_demo.c
@@ -327,6 +327,7 @@ bool window_sdl2_demo_resize (s_window_sdl2 *window,
(void) window;
assert(glGetError() == GL_NO_ERROR);
gl_ortho_resize(&g_ortho, 0, w, 0, h, -1, 1);
+ glViewport(0, 0, w, h);
assert(glGetError() == GL_NO_ERROR);
return true;
}