Three-dimensional graphics drawing apparatus

Claim 1

A 3-dimensional graphics drawing apparatus comprising: texture pattern memory means for storing a texture pattern in an address designated by 2-dimensional ST texture coordinates (s, t), said texture pattern constructed by a set of a plurality of kinds of texture pixels; display memory means for storing said texture pixels into an address designated by 2-dimensional XY display coordinates (X, Y) corresponding to a display screen and a 2-dimensional image of a surface shape of a 3-dimensional object formed by a set of polygons; enlargement mode setting means for setting an enlargement mode of a magnification N in which each of a plurality of pixels constructing said polygons is increased by N in the vertical direction and by N in the lateral direction in said display memory means; surface shape coordinate generating means for generating of 2-dimensional UV surface shape coordinates (u,v) defined by projecting a 3-dimensional object defined by set of said polygons which has been enlarged N times and to which said 2-dimensional texture pattern which has been enlarged N times has been adhered; conversion coefficient generating means for generating initial values of ST texture coordinates (s 0 , t 0 ) and increased amount values (K 1 , K 2 ) for coordinate conversion between polygon vertex coordinate values (u, v) and vertex coordinate values for the ST texture coordinates (s, t) corresponding to said vertex coordinate values (u, v); S coordinate register means for holding an S coordinate initial value (s 0 ); S coordinate increased amount register means for holding an increased amount value (K 1 ); S coordinate loop circuit means for adding the S coordinate initial value (s 0 ) and the increased amount value (K 1 ) each time an inputted coordinate value (u) of the UV surface shape coordinates (u, v) is between the vertexes, and for causing the result of the addition to be held as a new S coordinate initial value (s 0 ) in said S coordinate register means; S coordinate variation selecting circuit means for selecting and outputting a variation amount (.increment.s) designated by XY display coordinates (x, y) corresponding to the UV surface shape coordinates (u, v) and giving a variation of random coordinate positions when said enlargement mode is set; S coordinate variation adding means for supplying a stirred coordinate value (s+.increment.s) obtained by adding the variation value (.increment.s) to the S coordinate initial value (s 0 ) to said texture pattern memory means; T coordinate register means for holding a T coordinate initial value (t 0 ); T coordinate increased amount register means for holding an increased amount value (K 2 ); T coordinate loop circuit means for adding the T coordinate initial value (t 0 ) and the increased amount value (K 2 ) each time an inputted coordinate value (v) of the UV surface shape coordinates is between the vertexes, and for causing the result of the addition to be held as a new T coordinate initial value (t 0 ); T coordinate variation selecting circuit means for selecting and outputting a variation value (.increment.t) designated by XY display coordinates (x, y) corresponding to UV surface shape coordinates (u, v) and giving a variation of random coordinate positions when the enlargement mode is set; and T coordinate variation adding means for supplying a stirred coordinate value (t+.increment.t) obtained by adding the variation value (.increment.t) to the T coordinate initial value (t 0 ) to said texture pattern memory means, wherein the texture pixels are read out from said texture pattern memory means and display by the designation of said stirred coordinate values (s+.increment.s, t+.increment.t) of said S coordinate variation adding means and said T coordinate variation adding means, thereby making a random distribution in a boundary portion of each of the texture pixels which were enlarged to N times.