Three-dimensional shape data transforming apparatus

DETAILED DESCRIPTION It is therefore an object of the present invention to provide a 3D shape data transforming apparatus capable of reducing the amount of computations in transforming an original shape into an approximate shape and thereby achieving highly efficient processing.
In accordance with an aspect of the present invention, there is provided a three-dimensional shape data transforming apparatus comprising: shape storage means for storing shape data; a frame buffer made of a plurality of pixels for storing color information; a Z buffer for storing depth values (Z values) and corresponding to the pixels of the frame buffer; image generation means for projecting an original shape represented by shape data in the shape storage means onto a predetermined projection surface to prepare an image, the image generation means further storing color information into the frame buffer and depth values into the Z buffer; and vertex determination means for making the original shape correspond to an approximate shape (i.
e.
, shape before transformation) constituted by a plurality of designation points represented by two-dimensional coordinates, the vertex determination means further determining the coordinates of the vertexes to which the designation points are made to correspond in accordance with the two-dimensional coordinates of the corresponding designation points and with the corresponding depth values in the Z buffer.
The data constituted by the vertexes whose three-dimensional coordinates are determined by the vertex determination means are used as the data about the approximate shape representing the transformed original shape.
The invention as embodied above makes it possible to obtain, based on the depth values computed by the image generation means upon image generation and stored in the Z buffer, the coordinates of the vertexes constituting the approximate shape (i.
e.
, shape after transformation) made of a plurality of vertexes represented by three-dimensional coordinates.
The process eliminates the need for performing computations for intersection judgment as required by conventional apparatuses