| 摘要 |
An object of the invention is to draw the scope of shadows of a solid body, generated by light and illuminated regions of the solid body, formed by light, on a display device at high speed and with accuracy by means of a less and simple operation. A process of generating a shadow in 3-D computer graphics comprises the steps of forming a solid body as a shadow space of a polygon by causing respective vertices of the polygon to be shifted in the vector direction of the light rays to the boundary of the drawing space, increasing luminance within a scope of faces on the back side of the solid body as seen from the point of view at the time of drawing with respect to respective faces composing the solid body by adding to the extent of a constant for luminance adjustment to the luminance within the scope of the faces on the back side of the solid body, and decreasing luminance within a scope of faces on the front side of the solid body as seen from the point of view at the time of drawing by subtracting to the extent of the constant for luminance adjustment from the luminance thereof, wherein a change of luminance with respect to the polygon which is a shaded face is prohibited after processing of the shaded face.
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