JPS63200276A - Picking processor - Google Patents

Abstract

PURPOSE:To select a 3-dimensional pattern at a high speed by controlling the depth of a specific area defined after a cursor with use of a 2-split searching method. CONSTITUTION:A conversion matrix generating part 14 outputs a conversion matrix to define a specific area around a cursor moving over a 2-dimensional space of a display screen and to convert the specific area into a normal device space. A coordinate transforming circuit 3 performs matrix arithmetic by means of said transforming matrix. While a clipping circuit 4 performs clipping jobs. A depth control part 13-6 decides the clipping identification signal outputted from the circuit 4 and updates both a depth minimum register 13-1 and a depth maximum register 13-2. Then a specific area depth register 9 is updated by the output of an average value arithmetic circuit 13-1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a picking processing device for a three-dimensional graphics display device.

BACKGROUND OF THE INVENTION There is no literature that directly describes the picking process of a three-dimensional graphics display device. It is well known that the picking process is carried out in principle by determining the shape that generates a new vertex (hereinafter referred to as being clipped) when clipping is performed in a minute area around the cursor. This is shown in the literature. "Graphic Processing Engineering Using Computer Displays" by Yamaguchi, Nikkan Kogyo Shimbun, PP138-145. Figure 2 shows the picking process of a two-dimensional graphics display device. When clipping is performed in a minute area around the cursor, polygon 1 is clipped and polygon 2 is not clipped, making it easy to distinguish between the two. This method of performing clipping using a minute area around the cursor and determining the polygon to be clipped is effective.

When this method is applied to three-dimensional graphics, clipping is performed using minute solids around the cursor, and the polygon to be clipped is determined.

A conventional system for identifying and outputting clipping by minute solids around a cursor and clipped polygons is shown in the following document. J Erotic Club Clark, The
Geometry Engine: Abinirnisai Geometry System for Graphics”, comp
uter Graphics.

Human CM, Mol 1 e, $3, pp127-
133.19820 Although a specific configuration diagram of the picking processing device is not described, a configuration diagram that can be easily inferred is shown in FIG. 1 is a polygon vertex memory that stores the coordinate data of each vertex of a polygon defined in the three-dimensional world coordinate system;
2 is a transformation matrix storage memory that stores a 4-by-4 matrix for converting from a 3-dimensional world coordinate system to a 3-dimensional normal/device coordinate system, and 3 is a 4-by-4 matrix stored in the transformation matrix storage memory 2. This is a coordinate conversion circuit that converts the coordinates of each vertex stored in the polygon vertex memory 1. 4 is the regular device space (-1≦X≦1.-1≦Y
≦1゜0≦2≦1), an X clipping circuit 5 that clips on the plane x=-1 and the plane x=1, and a Y clipping circuit that clips on the plane Y=-1 and the plane Y=1. 6. Plane Z=o and z=1 and IJ, pink 2 clipping circuit 7
It consists of a cascade of .

8 is a cursor coordinate register for storing cursor coordinates;
It is composed of three registers 8-1 to 8-3 that store X, Y, and Z coordinate values (Xc, Yc, Zc).

9 is a specific area register that stores the size of a specific area defined around the cursor, a specific area width register 9-1 that stores the width (ΔX), and a specific area height register 9-2 that stores the height (Δy). , depth (Δ2) are stored in a specific area depth register 9-3. 1Q is a viewpoint coordinate register that stores the viewpoint coordinates for viewing a figure defined in the 3D world coordinate system, and the X, Y, Z coordinate values (Xs, Y
e, Ze) are stored in three registers 1o-1~
Consists of 1o-3. 11 is the cursor coordinate register 8
This is a transformation matrix generation unit that generates a coordinate transformation matrix of 4 rows and 4 columns from the specific area register 9 and viewpoint coordinate register 10.

In the above configuration, in order to display a polygon in a three-dimensional space, the transformation matrix generation unit 10 generates a 4-by-4 matrix for visual field transformation and perspective transformation from the contents of the viewpoint coordinate register 10, and converts the matrix into a transformation matrix storage memory 2. Store it in

The coordinate transformation circuit 3 transforms each vertex data stored in the polygon vertex memory 1 as shown in equation (1) using the 4 rows and 4 columns matrix hIJ stored in the transformation matrix storage memory 2.

However, X, Y, and Z are coordinate values before conversion, X', Y'.

Z' is the coordinate value after transformation. By clipping the output of the coordinate conversion circuit 3 with a clipping circuit 4, display data in the regular device space is obtained.

Next, during picking processing to select one of the displayed polygons, a polygon that is clipped by a minute specific area defined around the cursor is determined. Figure 4 shows the picking process. Polygons 1, 2, and 3 are displayed overlapping each other on the display screen, but at the cursor position shown in Figure 4, polygon 1 is clipped in a specific area around the cursor, so it is necessary to select polygon 1. be.

To achieve this, a coordinate transformation is further performed to convert the specific area around the cursor into the normal device space, and a polygon to be clipped in the normal device space is selected. The necessary coordinate transformation here can be accomplished by calculating the result of a transformation matrix that transforms the cursor position to the origin and a transformation matrix that expands the specific area into the regular device space. Therefore, coordinate transformation may be performed as shown in equation (4).

In the configuration shown in FIG. 3, when a pinking process request occurs, the conversion matrix generation unit 11 generates a cursor coordinate register 8.
A conversion matrix corresponding to equation (4) is generated from the contents of the specific area register 9. The matrix calculation of equation (4) is executed by the coordinate conversion circuit 3, and clipped by the clipping circuit 4. At this time, the clipping circuit 4 outputs a clipping identification signal for identifying the clipped polygon. Therefore, a desired polygon can be selected by observing the clipping identification signal.

Problems to be Solved by the Invention However, with such a configuration, polygon 1 cannot be selected unless a minute specific area is set at the position shown in FIG. Therefore, the thickness of the specific area cannot be made too large.

Therefore, in order for the user to select a desired polygon, it is necessary to delicately adjust the three-dimensional position of the cursor, resulting in a problem that picking is not easy to use.

In view of the above-mentioned problems, the present invention improves the usability of the user by moving the cursor only in the two-dimensional space of the display screen, and also automatically moves the polygon that is displayed in the foreground on the display screen. It is an object of the present invention to provide a picking processing device that can perform selection at high speed.

Means for Solving the Problems The present invention provides a coordinate conversion circuit that performs matrix operations of a 4-by-4 matrix, a clipping circuit that clips polygons in a three-dimensional regular device space, and a clipping identification output from the clipping circuit. A specific area depth output unit that uses signals to update the depth of a specific area defined around the cursor, and a 4-by-4 matrix that converts the specific area into normal device space from the cursor coordinates and the size of the specific area. The picking processing device includes a conversion matrix generation section.

Function The present invention has such a configuration, so that two parts of the display screen can be
A conversion matrix generation unit defines a specific area around a cursor that moves on a dimensional space, and outputs a conversion matrix for converting the specific area into a regular device space. Using this, a coordinate transformation circuit performs matrix calculations, and a clipping circuit performs clipping. At this time, the clipping identification signal is observed by the specific area depth output unit, and the depth of the specific area is controlled until only one polygon is clipped. The closest polygon in the list can be automatically selected. Moreover, since the depth of the specific area is controlled by the binary search method, high-speed selection is possible.

Embodiment FIG. 1 is a block diagram of a picking processing apparatus in an embodiment of the present invention. In FIG. 1, 1 is a polygon vertex memory, 2 is a transformation matrix storage memory, 3 is a coordinate transformation circuit, 4 is a clipping circuit, 5 is an X clipping circuit, 6
7 is a Y clipping circuit, 7 is a Z clipping circuit, 9 is a specific area register, and 10 is a viewpoint coordinate register, which have the same configuration as shown in FIG. 3. 12 is a cursor coordinate register that stores the display position of the cursor;
Unlike the configuration in the figure, the X coordinate value (Xc) and Y coordinate value (Y
It consists of two registers 12-1 and 12-2 that store c). Reference numeral 13 denotes a specific area depth output unit, which includes a minimum depth register 13-1 for storing the minimum value of the depth variation range (ΔZmin), a minimum depth register 13-1 for storing the minimum value of the depth variation range (ΔZmax);
), the maximum depth register 13-2 stores ΔZ wi
Average value calculation circuit 13-3 that calculates the average value of n and Δz wax o, input buffer 13-4 to the minimum depth register 13-1, input buffer 13-6 to the maximum depth register 13-2, specific area depth output The depth control section 13-6 controls the entire section 13. 14 is a transformation matrix generation unit that generates a coordinate transformation matrix of 4 rows and 4 columns from the cursor coordinate register 12, the specific area register 9, and the viewpoint coordinate register 1o.

The operation of this embodiment will be explained below. FIG. 6 shows the picking process for selecting one of the displayed polygons. Polygons 1, 2, and 3 are displayed overlapping each other on the display screen, but at the cursor position shown in Figure 5, it is necessary to select polygon 1, which is the closest polygon behind the cursor. be. To achieve this, consider a small area around the mud cursor with width ΔX and height Δy, and depth Δ2.
Select polygons that are clipped at a specific area with . The coordinate transformation required here has the same format as equation (4), but since the movement of the cursor is limited to the area on the display screen (Zc=O), it becomes equation (5).

In the configuration shown in FIG. 1, when a picking process request occurs, the conversion matrix generation unit 14 generates a cursor coordinate register 1.
2 and the contents of the specific area register 9, a conversion matrix corresponding to equation (5) is generated. The matrix calculation of equation (5) is executed by the coordinate conversion circuit 3, and clipped by the clipping circuit 4. At this time, the clipping circuit 4 identifies the clipped polygon and outputs an IJ sobbing identification signal. The clipping identification signal is input to the specific area depth output unit 13, a new depth is set in the specific area depth register 9-3, and the conversion matrix generation unit 14 again converts the 4 rows and 4 columns matrix corresponding to equation (6). generate. The above series of operations are repeatedly controlled by the specific area depth output unit 13 until the number of polygons to be clipped is one.

Next, the operation of the specific area depth output section 13 will be explained in detail. When a picking processing request occurs, the depth control unit 13
-6, set "o" in the minimum depth register 13-1 and "1" in the maximum depth register 13-2.
Controls two input cover sofas 13-4 and 13-5.

The average value calculation circuit 13-3 outputs “1” regardless of the input value.
” is output, and the specified area depth register 9
-3 is set to "1" and a computation start signal is sent to the conversion matrix generation section 14. When all polygons on one screen are clipped in a specific area with a depth of "1", there are three cases: when there is no polygon to be clipped, when there is only one polygon, and when there are two or more polygons. FIG. 6 shows an X-Z plan view formed by a cross section of the plane Y=Yc defined by the Y coordinate of the cursor position in each case. In FIG. 6, the polygon is a line of intersection with Y=Yc, and the specific area is indicated by a diagonally shaded rectangle with a width ΔX and a depth Δ2. When the depth is "1" and there is no polygon to be clipped (Figure 6a), there is no polygon to be selected, and when there is only one polygon to be clipped (Figure 6b) Beam IJ The polygon that has been removed is the polygon to be selected, and in either case, the picking process is completed in one process. If there are two or more polygons to be clipped (FIG. 6C), the specific area depth register 9
-3 is stored in the maximum depth register 13-2, the average value calculation circuit 13-3 is activated, and the minimum depth register 13-3 is activated.
-1 and the average value of the contents of the maximum depth register 13-2 are calculated to update the contents of the specific area depth register 9-3. The above control is repeated until there is only one polygon to be clipped, but there may be cases where there is no more polygon to be clipped. In that case, the specific area depth register 9-3
The contents of are stored in the minimum depth register 13-1, and subsequent control is performed. This depth control is shown in Figure 6 C-1 to Q.
-4.

As described above, according to this embodiment, the clipping identification signal output from the clipping circuit 4 is transmitted to the depth controller 13.
-6 makes a judgment, updates the minimum depth register 13-1 and the maximum depth register 13-2, and average value calculation circuit 13-3
The specific area depth register 9-3 is updated by the output. Therefore, the depth of a specific area defined behind the cursor moving on the display screen can be automatically controlled using the binary search method, and only the one polygon displayed in the foreground can be selected.

Effects of the Invention As described above, according to the present invention, it is possible to move the cursor on the display screen and select the polygon displayed in the foreground, thereby realizing a picking processing device that is easy for the user to use. Furthermore, since the depth of a specific area defined behind the cursor is controlled using a binary search method, high-speed selection is possible. Nowadays, there is an increasing demand for interactive systems using 3D graphics display devices, and the picking processing device of the present invention, which is easy to use and enables high-speed 3D figure selection, has a practical effect. big.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a picking processing device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of picking in a two-dimensional graphics display device, FIG. 3 is a block diagram of a conventional picking processing device, and FIG. 4 5 is an explanatory diagram of picking in a conventional picking processing device, FIG. 5 is an explanatory diagram of picking in a picking processing device according to an embodiment of the present invention, and FIG. 6 is an explanatory diagram of depth control by a specific area output unit. . 1... Polygon vertex memory, 2... Transformation matrix storage memory, 3... Coordinate transformation circuit,
4... Clipping circuit, 9-1...
Specific area width register, 9-2... Specific area height register, 9-3... Specific area depth register, 12... Cursor coordinate register, 13...
...Specific area depth output section, 13-1...
Minimum depth register, 13-2...Maximum depth register, 13-3...Average value calculation circuit, 13
-6...Depth control section, 14...Conversion mask) IJ space generation section. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Fig. 2 Fig. 3 Fig. 4 Fig. 5 Gakoshishimenga (and -0) Fig. 6 (Fushen-X Chichibari-Z)

Claims (2)

[Claims] (1) A polygon vertex memory that stores the coordinate data of each vertex of a polygon defined in the 3D world coordinate system, and a 4-by-4 matrix that converts from the 3D world coordinate system to the 3D regular device coordinate system. a coordinate transformation circuit that performs a matrix operation for coordinate transformation from the contents of the polygon vertex memory and the contents of the transformation matrix storage memory; and a three-dimensional regular device output from the coordinate transformation circuit. A clipping circuit that clips a polygon defined by a coordinate system in regular device space and outputs a clipping identification signal for the polygon with new vertices, and a cursor coordinate that stores the display position of a cursor that moves on the display screen. a specific area width register that stores the width of a specific area defined around the cursor, a specific area height register that stores the height of the specific area, and a specific area depth register that stores the depth of the specific area. , a specific area depth output unit that updates the value of the specific area depth register using the clipping identification signal output from the clipping circuit; and the content of the cursor coordinate register, the content of the specific area width register, and the specific area height. and a conversion matrix generation unit that generates a 4-by-4 matrix for converting the specific area into a regular device space from the contents of the depth register and the specific area depth register, and stores the matrix in the conversion matrix storage memory. Features of picking processing equipment. (2) The specific area depth output unit includes a minimum depth register that stores the minimum value of the depth variation range, a maximum depth register that stores the maximum value of the depth variation range, and a value of the minimum depth register and the maximum depth register. An average value calculation circuit that calculates an average value and stores it in the specific area depth register, and a clipping identification signal output from the clipping circuit indicate that two or more polygons have generated new vertices in the specific area. If there is no polygon that generates a new vertex in the specific area, the contents of the specific area depth register are stored in the minimum depth register. and a depth control unit that updates the depth of the specific area, respectively, and updates the contents of the specific area depth register until the number of polygons that generate new vertices in the specific area is one. The picking processing device according to item 1.