diff --git a/generic-pc/glfb.cpp b/generic-pc/glfb.cpp
index d993a3b..fb34b42 100644
--- a/generic-pc/glfb.cpp
+++ b/generic-pc/glfb.cpp
@@ -352,6 +352,18 @@ void GLFbPC::render()
                mReInit = false;
                mX = &_mX[mFullscreen];
                mY = &_mY[mFullscreen];
+               lt_info("%s: mX:%d\n", __func__, *mX);
+               if (*mX <= 0)
+               {
+                       lt_info("%s: fix mX:%d => 1280\n", __func__, *mX);
+                       *mX = 1280;
+               }
+               lt_info("%s: mY:%d\n", __func__, *mY);
+               if (*mY <= 0)
+               {
+                       lt_info("%s: fix mY:%d => 720\n", __func__, *mY);
+                       *mY = 720;
+               }
                if (mFullscreen) {
                        int x = glutGet(GLUT_SCREEN_WIDTH);
                        int y = glutGet(GLUT_SCREEN_HEIGHT);