| 摘要 |
PURPOSE:To shorten a calculation time by masking cubic element data positioned closer to a visual point as compared to the depth position of a cutting surface by means of a masking circuit and obtaining the depth position of cubic element data including a cut substance most close to the visual point by means of a priority encoder. CONSTITUTION:The titled memory is provided with a memory cell array 1 for storing cubic element data directly expressing the shape of a substance by an external cubic element data processor and a line decoder 2 for selecting a corresponding line based on a picture element address signal obtained from an external video signal control circuit. The memory is also provided with the masking circuit 4 for masking cubic element data closer to the visual point as compared to the depth position on a picture element position corresponding to a cutting surface for cutting a substance against the selected cubic element data and the priority encoder 5 for outputting a depth position including the substance close to the visual point out of the masked cubic element data. Consequently, the hidden-surface erasing processing of a cutting shape of a curve having a complexed shape can be rapidly displayed. |
