Patent ID: 7948487
Filing Date: 2011-05-24
Classification: G06T

Abstract:
1. An occlusion culling method, for performing on a computer graphics system, for excluding a hidden object that is behind another object, as seen from a point of view, from being rendered, when given a plurality of computer-generated objects, the method comprising: providing a processor readable memory comprising a Z-buffer, which contains Z values for determining a positional relationship between the objects in a depth direction, each Z value indicating a depth, from a point of view, for units of pixels; providing, for a target object being to be determined whether or not there is a possibility of being rendered, an external volume which includes the target object thereinside, and an internal volume, which is included inside and excludes the surfaces of the target object, the edge of the internal volume having no adjoining polygons attached thereto; comparing the Z values of rasterized pixels of the internal volume to be rendered with the Z values of corresponding pixels stored in the Z-buffer, and updating the Z values of the corresponding pixels in the Z-buffer with the Z values of the rasterized pixels of the internal volume to be rendered if the Z values of the rasterized pixels of the internal volume to be rendered indicate lying closer to the point of view than the Z values of the corresponding pixels in the Z-buffer do; and determining that the target object has a possibility of being rendered if it turns out that at least one of the rasterized pixels of the external volume to be rendered has a Z value that indicates lying closer to the point of view than the Z value of a corresponding pixel stored in the Z-buffer does.