| 摘要 |
PROBLEM TO BE SOLVED: To stabilize appearance probability of an advance notice image regardless of a display state of a background image by preventing situations that an advance notice image cannot be displayed.SOLUTION: Background images B2 are provided with six first specific parts P with the length X intervals, and a display region G relatively moves leftward with respect to the background images B2. When the background image B2 moves rightward for a distance X, a first specific part P2 and a second specific part Q2 move rightward together for the distance X and are positioned away from the display region G, and a first specific part P3 and a second specific part Q3 are positioned in the display region G. A plurality of first specific parts P and second specific parts Q are provided for the background image B2 so that at least one of them is normally displayed on a region in the background image B2 displayed on an image display device. A performance control CPU determines, on the basis of an advance notice determination ratio of "a first advance notice image", whether or not to display the first advance notice image on the first specific part even when any of the first specific parts P is displayed on the image display device. |
