Patent ID: 6750863
Filing Date: 2004-06-15
Classification: G06T

Abstract:
A method of adjusting luminance by light at high speed in rendering 3-D computer graphics, wherein in a process of generating a shadow in 3-D computer graphics, a solid body is drawn in a drawing space as a target for drawing, and subsequently, the process of generating the shadow is executed with respect to a polygon facing away from light rays among all polygons composing the solid body existing in the drawing space, said process comprising the steps of:forming a solid body as a shadow space of the 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; and 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 a constant value for luminance adjustment to the luminance within the scope of the faces on the back side of the solid body, while-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 value for luminance adjustment from the luminance within the scope of the faces on the front side of the solid body, wherein, when a polygon does not exist in the shadow space of the solid body, luminance of respective faces of the solid body is rendered to be in a state undergoing no change and, when the polygon exists in the shadow space of the solid body, a drawing process by hidden surface removal is not applied to the respective faces of the solid body, more backward than the polygon, as seen from the point of view at the time of drawing, and luminance in a region of hidden surface removal is not rendered brighter by the constant value, thereby executing a process of rendering luminance within the scope of a face of the solid body, lying in a forward position of the polygon as seen from the front face thereof, subtracted consequentially by the constant value, and creating a state equivalent to that where the shadow of the polygon is projected on the polygon from the viewpoint of representation, so that drawing of the shadow of the polygon is implemented on the polygon at high speed and with accuracy.