| 摘要 |
PURPOSE:To always ensure a complete drawing job with no misdrawing at all by delivering selectively the Z value of a Z buffer when the coincidence is obtained between the output of a register which designates a pattern drawing surface and the output of a buffer storing the information on said drawing surface and then delivering the Z value directly from a drawing device in case said coincidence is not obtained. CONSTITUTION:A Z buffer 3 stores the Z coordinates of a pattern whose hidden surface is erased in response to the X and Y coordinates among those 3-dimensional coordinates X, Y and Z delivered from a vector drawing device. Containing such buffer 3, a graphic display device draws a pattern on another pattern. This display device includes a plane iD register 11 which designates a surface where a pattern is drawn in a drawing state, a P buffer 12 which stores the information on the surface that is decided by the points corresponding to the X and Y values on a pattern, and a means which selects the Z value of the buffer 3 when the coincidence is obtained between the outputs of the register 11 and the buffer 12 and then selects the Z value delivered from the vector drawing device for output when no said coincidence is obtained. Thus it is possible to avoid the misdrawing caused by the interpolation of each Z value when a pattern is drawn. |
