| 摘要 |
PURPOSE:To erase quickly a hidden surface and a hidden line by classifying a graphic into a triangle from its vertex and diagonal line and taking the vertex coordinates, an outward normal vector and the infinite apocenter of the vector for data. CONSTITUTION:When two independent graphic data to be displayed are outputted from a host computer 2, a triangle dividing processing part 1 classifies each graphic into a triangle with the aid of the diagonal line and obtains the vertex coordinates of a triangle forming each graphic model. On the other hand, coordinate data on the vertex of the triangle of the triangle, which is liable to intervene the triangle is outputted to a coordinate converting circuit 3 to obtain the coordinates of the projected image. Data on the displayed triangle and the projected image is transmitted to a sorting out circuit 4, and such decision is made whether or not the triangle develops the intervension. When the intervention occurs, data relating to the projected image is outputted to an intervention decision processing part 5. With respect to the side where the side of the displayed triangle and that of the projected image intersect each other, the processing part 5 calculates coordinates of the intersection. According to the arithmetic result, a shape deciding circuit 10 returns the data to the processing part 1 when the graphic is the one having more than four vertexes. |
