A projector includes a coordinate acquiring unit configured to acquire a coordinate of a position pointed by a pointer, a sub-processor configured to render an image on the basis of the coordinate, and a main processor configured to output image data of the image rendered by the sub-processor. The projector performs, according to a predetermined condition, using the main processor, rendering in the same manner as the sub-processor on the basis of the acquired input coordinate, superimposes the rendered image on the rendered image output by the sub-processor to generate a superimposed image, and outputs the superimposed image.