JPS62152077A - Segment managing device - Google Patents

Abstract

PURPOSE:To operate the segment management at a high speed by providing an associative memory storing coordinate data for left/right ridge lines constituting a projected active polygon and an adder to update the coordinate data. CONSTITUTION:A vertical coordinate Yend of an end point of each line segment deciding the boundary of a projected polygon constituting a three-dimensional object, a horizontal coordinate X at a present scanning line position, a depth coordinate Z, a horizontal coordinate displacement dX/dY as each advance of one scanning line, a depth coordinate displacement dZ/dY and an effective data flag V are stored in an associative memory 1 by using a polygon number as a key. A current scan line position Ycur is stored in a current vertical coordinate register 2. The effective segment information is read sequentially from the memory 1, the coordinate Yend is fed to a comparator 5 via a selector 4, compared with the position Ycur in the register 2. When Ycur<Yend, an adder 7 adds (X+dX/dY) and (Z+dZ/dY) and the result is written in the memory 1 via a selector 6 for the revision. When Ycur>=Yend, the flag V is reset and the result is written.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a segment management device in a three-dimensional computer graphics device that projects and displays a three-dimensional polyhedral object on a two-dimensional screen while performing hidden surface processing. be.

Conventional technology When displaying a composite of three-dimensional objects on a two-dimensional screen, the phenomenon in which an object in the foreground hides part or all of an object further back must be handled in some way to create a raster image. The color and brightness of each pixel must be output to the display device in the order of scanning. Such three-dimensional graphics devices generally have a configuration as shown in FIG.

First, the coordinate conversion/perspective conversion device 11 converts the coordinates of each vertex of an object defined as a polyhedron on the world coordinate system to the coordinate system seen from the viewpoint, and outputs data in the regular device coordinate system. In the regular device coordinate system, the entire visible region is mapped inside a cube whose coordinate axes x, y, and z have lengths of 1. Next, the display control device 12 performs hidden surface processing on a plane (polygon) made up of vertices having these converted coordinate values, and then outputs brightness information to the display device 16. The Watkins method has been known as a method for configuring this display control device. This method is Gee, Nis, Watkins.

``A real-time visible surface algorithm''.

University of Utah, Department of Computer Science.

UT EC-CS C-70-101, June 1970, and Fujio Yamaguchi.

6 Graphic processing engineering using computer displays” 1 Nikkan Kogyosha, 1981, Section 5.7.9 (PP, 281-292) This method is explained in detail in the display control device 12 in Fig. The processing program within is separated into a segment management section 13 and a hidden surface processing section 14.

The hidden surface processing unit 14 performs hidden surface processing based on depth data (gradient) for each scan line corresponding to the rask scan of the display device 15, and the segment management unit 13 changes the depth data every time the scan line changes. The starting point and ending point on each scan line of the polygon are calculated and output to the hidden surface processing unit 14. Fig. 3 shows this situation, and Fig. a shows the X-axis and Y-axis of the normal device coordinates on the display device. 16
This normal device coordinate system corresponds to the horizontal and vertical axes of A view taken from the front is shown in FIG. 3 (1), and a cross section at Y=y is shown in FIG. 3C. The hidden surface processing unit 14 in FIG. 2 performs hidden surface processing by paying attention to the coordinates of both end points of the segment 21 (the intersection line of the polygon 20 and the scan line surface) in FIG. 3C, especially the depth data Ze and zr. The segment management unit 13 in FIG. 2 follows the constantly changing scan line in FIG.
Output to 4. This segment management unit 13 utilizes the fact that the ridge line constituted by the polygon 20 is always a straight line.
The processing flow is as shown in FIG. Polygon that intersects the current scan line surface (active polygon)
This information is stored in the main memory in a list structure and managed. When a new scan line is created, if a new ridge line enters (becomes active), this list is updated 2 and added to it, and if there is a ridge line to leave, the list is updated again. Remove. Then perform hidden surface processing on all active polygons,
Calculate X=X+dX/dY Z=Z+dZ/dY degrees for all ridges for the next scan line. If dX/dY and dZ/dY are calculated in advance, the calculations can be made incrementally each time the scan line changes, so the program can be executed at high speed.

Problems to be Solved by the Invention However, the above configuration has the disadvantage that there is a limit to speedup because the active polygon table having a list structure in the main memory is managed by a sequential processing processor. was.

In view of this point, it is an object of the present invention to provide a segment management device that can perform the segment management described above at high speed.

゛Means for Solving the Problems The present invention is a segment management device equipped with an associative memory for storing coordinate data of left and right ridge lines constituting a convex active polygon, and an adder for updating this coordinate data. be.

Effects According to the present invention, with the above-described configuration, while the polygon is active for the scan line, the x and z coordinate values of the left and right ridge lines and their displacement information (dX/dY).

dZ/dY) in the associative memory, and each time the scan line changes, if there is an approach ridge line, write it into the associative memory using the polygon number as a key, and then write the current X for all active polygon segments.

Two coordinates are read out, and at the same time, displacement information is added to these using an adder for areas other than the exit ridge line, and the result is written into the associative memory again.

Embodiment FIG. 1 shows a block diagram of a segment management device in an embodiment of the present invention. In FIG. 1, 1 is an associative memory, 2 is a current vertical coordinate register, 3 is an incrementer, and 4 and 6 are selector, 5 is vertical coordinate comparator, 7
is an adder.

The operation of the segment management device of this embodiment configured as described above will be described below.

The associative memory 1 stores the X coordinate, 2 coordinate, and the X coordinate at the time of the current scan line for each of the left and right ridge lines, and the X coordinate when the scan line moves to the next line.

z Locus mo change i, dX/dY, dZ/dY, and the Y coordinate of the end point of the ridge line (Yend” valid data flag (
V), and can be read/written associatively using the polygon number PN as a key. The current scan line position (Ycur) is stored in the current vertical coordinate register 2.

From the front stage of the segment management device of the present invention, line segment information (belonging polygon number, Coordinates of the starting point (X
,,Y,,Z,).

and the vertical coordinate Y of the end point. , horizontal displacement dX/dY of the crest line
, depth displacement (dZ/dY) are supplied.

First, the comparator 5 inputs the above Y via the selector 4.
and the data YCur of the current vertical coordinate register 2, and if they match, the line segment information is written as an approach ridge line into the associative memory using the polygon number as a key. If there is no corresponding valid polygon number, it will be newly registered as a new segment, and if there is, it will be written to the invalid one of the left and right crest line data storage areas, and the segment information will be updated. For the data written at this time, the valid data flag CVe(vr) is turned ON.

Next, valid segment information is sequentially read from the associative memory, and among them, the polygon number PN and left and right horizontal and depth coordinates (X, Ze, Xr, Zr) are output to the outside of the system. These data become input data for the next-stage hidden surface processing device. Of the segment information leaked at this time, the end point vertical coordinates Y/end and rend of the left and right ridge lines are supplied to the comparator 5 via the selector 4, and are also compared with Ycu. If Ycur < Y$end, then X, 7
= X e+ΔXe/ΔY, Zl=Zt2+Δz,/
When ΔY or Ycur<Yrond, xr zero xr + ΔX, /Δy, zr=z, +Δzr/ΔY
is calculated by the adder 7, and the result is written to the associative memory 6 via the selector 6 for updating. However, if YCur≧
Y,, nd, or Y. When ur≧Yrend - This means that this crest line is delayed, so turn off the valid data flags (V or vr) corresponding to the left and right and write to the above associative memory.O Perform all of the above associative memory update procedures. When completed for the valid segment of the current vertical coordinate register 2
The content Ycur is incremented by 1 by the incrementer 3 and written into the current vertical coordinate register 2 again, and the process moves on to the next scan line.

As described above, according to this embodiment, by managing active polygons using an associative memory, it is possible to significantly speed up processing.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, according to the present invention, segment management of active polygons in a method of performing hidden surface processing in units of scan lines can be extremely speeded up, and its practical effects are significant.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a segment management device according to an embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams of the basic concept of a three-dimensional graphics device to which the present invention relates, and FIG. 4 is a block diagram of a segment management device according to an embodiment of the present invention. It is a flow diagram of a management part. 1... Content addressable memory, 2... Current vertical coordinate register, 6... Vertical coordinate comparator, 7.
...Adder. Figure 1 Figure 3 φ0

Claims (1)

[Claims] A three-dimensional object is constructed in a three-dimensional computer graphics device that scans and displays an object defined in a three-dimensional space horizontally on a two-dimensional screen of a raster scan type display device while performing hidden surface processing. The vertical coordinate (
Y_e_n_d), horizontal coordinate (X), depth coordinate (Z) at the current scan line position, horizontal coordinate displacement (dX/dY) for each scan line progress, depth coordinate displacement (
dZ/dY) and a valid data flag indicating that these data are valid for the left and right ridge lines of the polygon, and an associative memory that can read and write using the polygon number as a key and the current scan line position. (Y_c_u_r) and the starting point (2
The endpoints (the one with the smallest vertical coordinate) are fed in order from outside the system, and the belonging polygon number,
When the starting point vertical coordinate matches the contents of the current vertical coordinate register (Y_c_u_r) in the line segment information that has vertical, horizontal, and depth coordinate data of the starting point and ending point,
A means for registering this line segment information in the associative memory, and after the registration procedure, sequentially reading out valid segment information from the associative memory, polygon numbers, horizontal coordinates of left and right ridge lines,
means for outputting depth coordinates outside the system; a comparator for comparing the end point vertical coordinates of the left and right ridge lines among the simultaneously read segment information with the contents of the current vertical coordinate register (Y_c_u_r); The output is Y_c_u
When _r<Y_e_n_d, d is added to the corresponding X and Z data of the left and right crest lines among the read segment information.
means for adding each of X/dY and dZ/dY, writing and updating the data together with the valid data flag in the associative memory, turning off the valid data flag for the rest, and writing in the associative memory; and everything in the associative memory. A segment management device characterized by comprising means for incrementing the current vertical coordinate register by 1 when the updating procedure is completed for the valid data.