Image processing unit and method including blending processing

Abstract

The present invention allows executing blending processing for translucent polygons sequentially from the polygon at the front. The present invention is characterized in that rendering processing for translucent polygons is executed sequentially from the polygon at the front in the display screen. Therefore when color data T and opacity &agr; are provided to the nth polygon of the polygons sequentially arranged from the front in the display screen, components for the opacity &agr; of the nth polygon out of the color data T of the nth polygon is added to the image data D up to the (n−1)th polygon according to the accumulated transparency value X of the (n−1) number of polygons positioned at the front for rendering processing. This rendering processing is executed for all polygons, and the final image data D is used as image data for display. In accordance with the above image processing, translucent polygons can be sequentially processed from the front, so rendering processing of important polygons positioned at the front in a display screen is not omitted, even if the time between frames is short. Therefore images with smooth movement can be reproduced without stopping movement of important characters comprised of polygons. The above image processing can be applied to general blending processing as well.