| 摘要 |
Apparatus and methods for displaying two and three dimensional graphics within a plurality of windows on a display system. The display system includes a central processing unit (CPU) which provides RGB data to a bit-mapped display memory coupled to a cathode ray tube (CRT) display. A Z-buffer memory is provided with a Z-value for each RGB data point corresponding to a point on the object to be displayed. The Z-buffer is organized such that the value of the entire n bit buffer (0 through 2n-1) identifies the window in which the graphics and/or text is displayed. For windows in which only two dimensional (2D) graphics/text is displayed, the Z-value is the same for both the window and each RGB point of the image. For windows which display three dimensional (3D) graphics, a range of Z-values for the buffer are provided which define the window boundaries. Images to be displayed within a 3D window must have Z-values which fall within the particular window's Z-value range. Within each window traditional Z-buffering techniques are utilized to provide hidden surface elimination. The apparatus and methods also permit the use of hither and yon planes to selectively view cross-sections of objects within a 3D window.
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