公开(公告)号：JPH0273479A

公开(公告)日：1990-03-13

申请号：JP22444888

申请日：1988-09-09

Applicant: IBM JAPAN

Inventor： MATSUMOTO TAKASHI

IPC: G06T15/60 ,  G06T15/10 ,  G09B9/30

Abstract: PURPOSE:To realize the direct decision of the shadow of a recessing object to omit the necessity to divide a recessing object into the projecting objects and at the same time to simplify the decision and generation of the shadows to increase the processing speed of a graphic processor by providing a pseudo hidden surface erasing part, a hidden surface erasing part, a shading part, etc. CONSTITUTION:When the normal polygons are supplied to a hidden surface erasing part 9 and a shading part 10, the part 10 produces the pixel value that undergone the shading based on the span data and updates the data on a pixel value buffer 12 with reflection of the process of the part 9. While the span data on each shadow polygon are successively supplied to a pseudo hidden surface erasing part 13. Then the part 13 evolves the depth data on the shadow polygon and compares it with the depth data on a Z buffer 11 that is decided after the hidden surface is erased at each pixel position. The result of this comparison is inputted to a changing part 16 via a temporary shadow finding (TSF) flag buffer 14 and a final shadow finding (FSF) flag buffer 15. Then the input pixel value is changed for execution of a shadowing process. Thus it is not required to divide a recessing object into the projecting objects and at the same time the processing speed is increased for a graphic processor.

公开(公告)号：JPH02132572A

公开(公告)日：1990-05-22

申请号：JP28569888

申请日：1988-11-14

Applicant: IBM JAPAN

Inventor： MATSUMOTO TAKASHI

IPC: G06T11/00 ,  G06T15/30

Abstract: PURPOSE:To produce a picture at a high speed by comparing a depth value with a value stored in a buffer to perform a clipping operation to an optional three-dimensional area when a display subject is evolved to a pixel. CONSTITUTION:Plural buffers are prepared to store the depth value for each pixel of a screen, and the depth value of the interface of a clipping area is evolved and stored in the same procedure as the evolution of the component surface of a display subject. Then an object serving as the display subject is evolved into the data for each pixel, and it is decided whether the corresponding data belongs to the object set in the slipping area or not by using the depth value of the interface in the buffer. If so, the data may possibly be displayed on the screen and it is decided whether the data should be displayed on the screen or not after the erasion of a hidden surface. If not, the data is disused since the object has no possibility of display in terms of the relevant pixel. Thus it is possible to produce a picture undergone a three-dimensional clipping operation at a high speed.