A video game apparatus used as a three-dimensional imaging apparatus includes a CPU. The CPU works together with a GPU to generate and display a game image. More specifically, some objects are arranged in a virtual three-dimensional space. The virtual three-dimensional space is converted into a viewpoint coordinate and then projected and converted. After the projection conversion, determination points are set corresponding to a specific object, and the degree to which the specific object is hidden is calculated on the basis of a Z value of the specific object and the Z values of the determination points. At least one aspect of the display may be changed according to the degree to which the specific object is hidden.