Apparatus and method for performing hidden surface removal and computer program product

An image processing method comprising:

• calculating a polygon Z value which is a coordinate value in a depth direction of a pixel located at a closest point to a viewpoint among pixels corresponding to vertexes of a polygon which is a unit of drawing;
• calculating a block Z value which is a coordinate value, in the depth direction, of a pixel located at a closest point to the viewpoint in a block, which is a section formed as a part of a drawing area in which an image of three-dimensional computer graphics is drawn, among pixels included in a plane formed by the polygon;
• selecting a Z value of a pixel which is closer to the viewpoint from the polygon Z value and the block Z value, an estimate Z value which is an estimate of a coordinate value in the depth direction of a pixel located at a closest point to the viewpoint in the polygon in the block;
• and
• eliminating drawing of the polygon in the block when a pixel corresponding to the estimate Z value is located at a farther point from the viewpoint than a pixel corresponding to a hierarchical Z value, the hierarchical Z value being a coordinate value, in the depth direction, of a pixel located at a farthest point from the viewpoint among pixels already drawn in the block and being stored in a storing unit.

A computer program product having a computer readable medium including programmed instructions for image processing, wherein the instructions, when executed by a computer, cause the computer to perform:

• calculating a polygon Z value which is a coordinate value in a depth direction of a pixel located at a closest point to a viewpoint among pixels corresponding to vertexes of a polygon which is a unit of drawing;
• calculating a block Z value which is a coordinate value, in the depth direction, of a pixel located at a closest point to the viewpoint in a block, which is a section formed as a part of a drawing area in which an image of three-dimensional computer graphics is drawn, among pixels included in a plane formed by the polygon;
• selecting a Z value of a pixel which is closer to the viewpoint from the polygon Z value and the block Z value, an estimate Z value which is an estimate of a coordinate value in the depth direction of a pixel located at a closest point to the viewpoint in the polygon in the block;
• and
• eliminating drawing of the polygon in the block when a pixel corresponding to the estimate Z value is located at a farther point from the viewpoint than a pixel corresponding to a hierarchical Z value, the hierarchical Z value being a coordinate value, in the depth direction, of a pixel located at a farthest point from the viewpoint among pixels already drawn in the block and being stored in a storing unit.

An image processing apparatus comprising:

• means for storing a hierarchical Z value which is a coordinate value, in a depth direction, of a pixel located at a farthest point from a viewpoint among pixels already drawn in a block, the block being a section formed as a part of a drawing area in which an image of three-dimensional computer graphics is drawn;
• means for calculating a polygon Z value which is a coordinate value, in the depth direction, of a pixel located at a closest point to the viewpoint among pixels corresponding to vertexes of a polygon which is a unit of drawing;
• means for calculating a block Z value which is a coordinate value, in the depth direction, of a pixel located at a closest point to the viewpoint in the block among pixels included in a plane formed by the polygon;
• means for selecting a Z value of a pixel which is closer to the viewpoint from the polygon Z value and the block Z value as an estimate Z value which is an estimate of a coordinate value, in the depth direction, of a pixel located at a closest point to the viewpoint in the polygon in the block;
• and
• means for eliminating drawing of the polygon in the block when a pixel corresponding to the estimate Z value is located at a farther point from the viewpoint than a pixel corresponding to the hierarchical Z value.