JP3233640B2 - Clipping processing device, three-dimensional simulator device, and clipping processing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a clipping processing device, a three-dimensional simulator using the clipping processing device, and a clipping processing method.

[Background Art] Conventionally, various types of three-dimensional simulators have been known for use in, for example, a three-dimensional game or a simulator for controlling an airplane or various vehicles. Such 3
The three-dimensional object 300 shown in FIG.
Is stored in the apparatus in advance. The three-dimensional object 300 represents a display object such as a landscape that the player (viewer) 302 can see through the screen 306. And this display object is a three-dimensional object
The pseudo three-dimensional image (projected image) 308 is transformed into a screen 3 by performing perspective projection transformation of the image information of 300 on the screen 306.
The image is displayed on 06. In this device, the player 302
However, when an operation such as rotation and translation is performed using the operation panel 304, a predetermined three-dimensional calculation process is performed based on the operation signal. Specifically, first, the player 30
Calculation processing is performed to determine how the viewpoint position, line-of-sight direction of the second, or the position, direction, etc. of the moving body on which the player 302 rides change. Next, an arithmetic process is performed to determine how the image of the three-dimensional object 300 looks on the screen 306 in accordance with the change in the viewpoint position, the line of sight, and the like. The above arithmetic processing is performed in real time following the operation of the player 302. This allows the player 302 to
It is possible to see in real time a change in the viewpoint or the direction of the line of sight or a change in the scenery or the like due to a change in the position or direction of the moving body on which the user is riding as a pseudo three-dimensional image, and simulate a virtual three-dimensional space. You will be able to experience it.

FIG. 18 shows an example of the configuration of such a three-dimensional simulator device. In the following description, the description will be given taking a case where the three-dimensional simulator device is applied to a three-dimensional game as an example.

As shown in FIG. 18, this three-dimensional simulator device
Operation unit 510, virtual three-dimensional space calculation unit 500, image synthesis unit 51
2, composed of CRT518.

In the virtual three-dimensional space calculation unit 500, a virtual three-dimensional space is set according to an operation signal from the operation unit 510 and a gate program stored in the central processing unit 506. That is, an operation of locating the three-dimensional object 300 at which position and in which direction is performed.

The image synthesizing unit 512 includes an image supply unit 514 and an image forming unit 516. Then, the image synthesizing unit 512 synthesizes the image of the pseudo three-dimensional image according to the setting information of the virtual three-dimensional space by the virtual three-dimensional space calculation unit 500.

By the way, in the present three-dimensional simulator device, the three-dimensional object forming the virtual three-dimensional space is represented as a polyhedron divided into three-dimensional polygons. For example, in FIG. 17, a three-dimensional object 300 is a three-dimensional polygon (1) to (6).
(Polygons (4) to (6) are not shown) are represented as polyhedrons. Then, the coordinates of each vertex of the three-dimensional polygon, accompanying data, and the like (hereinafter, referred to as vertex image information) are stored in the three-dimensional image information storage unit 552.

In the image supply unit 514, various calculations such as rotation and translation, and various coordinate conversions such as perspective projection conversion are performed on the vertex image information in accordance with the setting information of the virtual three-dimensional space calculation unit 500. Then, the vertex image information for which the arithmetic processing has been completed is
After being rearranged in a predetermined order, the image is output to the image forming unit 516.

The image forming section 516 includes a polygon generating circuit 570 and a pallet circuit 580. The polygon generating circuit 570 includes a contour point calculating section 324 and a line processor 326. In the image forming unit 516, a calculation process of filling all the dots inside the polygon with predetermined color data or the like is performed in the following procedure.

That is, first, the contour point calculation unit 324 calculates left and right contour points, which are intersections between the contour line of the polygon and the scanning line. Next, the line processor 326 paints the portion surrounded by these left and right contour points with the designated color data. Thereafter, the filled color data is subjected to RGB conversion in the palette circuit 580, and is output and displayed from the CRT 518.

Now, in the three-dimensional simulator apparatus having the above configuration, the following calculation is performed by the image supply unit 514.

That is, taking the driving game as an example, as shown in FIG. 19, the three-dimensional objects 300 and 3 representing the steering wheel, the building, the signboard, and the like read from the three-dimensional image information storage unit 552.
33 and 334 are arranged on a three-dimensional space represented by a world coordinate system (XW, YW, ZW). Thereafter, the image information representing these three-dimensional objects is coordinate-transformed into a viewpoint coordinate system (Xv, Yv, Zv) based on the viewpoint of the player 302.

Next, image processing called clipping processing is performed. Here, the clipping process means that the player 30
Image information outside the field of view 2 (or outside the field of view of a window opened in three-dimensional space), ie, clipping planes 1, 2,.
Image processing for removing image information outside an area surrounded by 3, 4, 5, and 6 (hereinafter referred to as a display area 20).
That is, the image information required for the subsequent processing by the three-dimensional simulator is only the image information within the field of view of the player 302. Therefore, if other information is removed in advance, the load of subsequent processing can be reduced. That is, since objects exist in all directions around 360 degrees around the player 302, if only objects within the field of view are processed, the amount of data to be processed thereafter is greatly reduced, and in particular, In a three-dimensional simulator apparatus that performs image processing in real time, the image processing is indispensable.

This will be described in more detail with reference to FIG. That is, image information of an object outside the field of view of the player 302 (outside the display area 20), for example, a three-dimensional object 334 representing a signboard or the like passing out of view and passing behind is removed. This removal processing is performed on the clipping surfaces 1 to 6
Is determined by determining whether each of the surfaces is inside or outside the display area, and removing only objects outside of all the surfaces.

On the other hand, in the three-dimensional object 333 such as a building at the boundary of the display area 20, the part outside the display area 20 is removed, and only the part inside the display area 20 is used for the subsequent image processing. You. Further, the image information of the three-dimensional object 300 such as the handle completely included in the display area 20 is used as it is for subsequent image processing.

Finally, the perspective projection transformation to the screen coordinate system (XS, YS) is performed only on the object within the display area 20,
After that, a sorting process is performed.

As described above, since the clipping process can greatly reduce the image data used for the image processing after the clipping process, it is an essential image process in this kind of three-dimensional simulator device. .

However, as shown in FIG. 19, this clipping process must be performed for all of the clipping planes 1 to 6, and in practice, in the three-dimensional operation unit 316, the speed of the entire circuit is most limited. Image processing.

In particular, in a three-dimensional simulator device which must perform image processing of a pseudo three-dimensional image in real time, that is, a device in which a display screen is switched every (1/60) second, for example, a decrease in speed directly decreases the image quality. It becomes a big problem. Therefore, speeding up and optimizing such clipping processing is a major technical problem in this type of three-dimensional simulator.

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-described technical problems, and has as its object to provide a high-speed clipping processing apparatus which is particularly suitable for a three-dimensional simulator apparatus which performs image processing in real time. Is to provide.

In order to achieve the above object, the present invention provides a clipping processing apparatus for performing a clipping process using a plurality of clipping planes on a three-dimensional object represented by a set of a plurality of polygons. Means for storing index data for specifying the clipping plane to be used,
Means for storing the priority of the clipping plane by storing the index data from the highest storage location to the lower storage location of the storage means in the order in which the clipping process is performed; and storing the priority of the index data in the priority storage means. Means for setting an initial value; means for reading the index data of the clipping plane from the priority storage means; priority changing means for changing the index data read by the reading means and writing it back to the priority storage means; Clipping operation means for performing a clipping operation process on a polygon to be processed by using a clipping surface designated by index data sequentially read from the highest storage location of the storage means by the reading means, An inside / outside determination unit configured to determine whether a polygon to be processed is located in a surface area, a boundary area, or a non-display area of the clipping surface; and the inside / outside determination unit sets the polygon to a boundary area. Means for calculating an internal dividing point between the polygon and the clipping plane when it is determined to be present, and invalidating the polygon when the polygon is determined to be in the display outside area by the inside / outside determination means. Means for performing an arithmetic operation, wherein the priority changing means determines that the processing target polygon is located in a non-display area of the clipping plane by the clipping arithmetic means. Is transferred to the uppermost storage location of the storage means.

According to the present invention, the initial value of the index data is set in the priority storage means by the initial value setting means. If it is determined that the polygon to be processed is located outside the display area of the clipping plane, the index data of the clipping plane is transferred to the highest storage location of the storage unit. As a result, when the clipping process is connected to polygons included in the same three-dimensional object and performed, the priority written in the priority storage unit is optimized. As a result, the clipping processing time can be statistically reduced, and the clipping processing speed can be greatly improved. As a result, it is possible to provide a clipping processing device most suitable for a three-dimensional simulator device that performs image synthesis in real time.

Also, the present invention is characterized in that when the priority changing means determines that the polygon to be processed is located in a non-display area of the clipping plane by the clipping calculating means, the index data of the clipping plane is stored in the storage means. And the index data stored from the highest storage location to the storage location one level higher than the storage location of the transferred index data is sequentially decremented to the lowermost storage location. It is characterized by including means for transferring to a storage location.

According to the present invention, if the polygon to be processed is determined to be in the non-display area of the clipping plane, the index data of the clipping plane is only transferred to the highest storage location of the storage unit. Instead, the other index data is sequentially moved down and transferred to a lower storage location. As a result, the index data of the clipping plane that is easy to clip out
The data is stored sequentially from the top of the storage means.
As a result, for example, even if clipping out cannot be performed by the clipping plane specified by the top index data, clipping out can be performed by the clipping plane specified by the next index data, and the clipping processing time is further reduced. It becomes possible.

Further, the present invention provides a method for performing the clipping process on a polygon constituting a three-dimensional object.
The apparatus further includes means for performing pre-processing on the entire three-dimensional object, wherein the pre-processing means sets a zone for trivial clipping having a predetermined width formed so as to include the clipping plane, and And a pre-processing determination unit that determines whether the three-dimensional object is located in the display region or the non-display region of the zone. If determined, the clipping process for the polygons constituting the three-dimensional object is omitted, and if determined to be in the boundary area of the zone, the clipping process is performed for the polygons constituting the three-dimensional object. Means for designating the application.

According to the present invention, the three-dimensional object is
It is determined whether the zone for the trivial clipping is in the display area, the boundary area, or the non-display area. If it is determined that the three-dimensional object is in the display area or the non-display area of the zone, the clipping processing of the polygon included in the three-dimensional object is not performed. As a result, the total amount of processing can be significantly reduced, and the clipping processing speed can be significantly improved.

Also, the present invention provides a perspective projection conversion process for a polygon to be processed, wherein the interior dividing point computing unit included in the clipping computing unit changes an operation coefficient used for the interior dividing point calculation. Characterized in that it includes means for applying

According to the present invention, not only the clipping processing but also the perspective projection conversion processing can be performed by one clipping processing apparatus, so that the hardware can be downsized. As a result, it is possible to improve the cost performance of the apparatus. In addition, the present invention sets the initial value set by the initial value setting means for each three-dimensional object in accordance with the display state of the three-dimensional object composed of polygons. Is included.

According to the present invention, the initial value of the priority can be set for each three-dimensional object. Therefore, by changing the initial value according to the display state of the three-dimensional object, it is possible to perform an optimal clipping process. Becomes

In addition, the present invention provides a 3
A three-dimensional simulator device, characterized by including at least an image synthesizing means for synthesizing a view image viewed by a viewer in a virtual three-dimensional space using the polygons subjected to the clipping processing by the clipping processing device.

ADVANTAGE OF THE INVENTION According to this invention, the number of polygons which need to be processed by an image synthesis means can be reduced sharply by performing a clipping process by a clipping processing apparatus, and the three-dimensional simulator apparatus which can perform real-time image synthesis is provided. It can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a preferred example of a clipping processing device according to the present invention.

FIG. 2 is a block diagram showing an example of a three-dimensional simulator to which the clipping processing device according to the present invention is applied.

FIG. 3 is a schematic explanatory diagram illustrating the concept of texture mapping.

FIGS. 4A and 4B show an example of a data format of data handled by the present embodiment.

FIG. 5 is a block diagram illustrating an example of an image supply unit to which the clipping processing device according to the present invention is applied.

FIGS. 6A, 6B, and 6C are schematic explanatory diagrams illustrating a case where the clipping processing apparatus according to the present embodiment is used in the reentrant mode.

FIGS. 7A, 7B, 7C, and 7D are schematic explanatory diagrams showing an example of initial mode designation data, priority designation data, and a rewriting operation of a clipping register.

FIGS. 8A, 8B, 8C, 8D, and 8E are schematic explanatory diagrams showing an application example of the clipping processing device according to the present embodiment.

FIG. 9 is a block diagram showing a configuration of a clipping processing device when performing a trivial clipping process.

FIG. 10 is a schematic explanatory diagram for explaining a technique of the trivial clipping process.

FIG. 11 is a block diagram showing a specific circuit configuration of a priority register (priority storage means).

FIG. 12 is a block diagram illustrating a specific circuit configuration of the priority changing unit.

FIGS. 13A, 13B, 13C, and 13D are schematic explanatory diagrams showing operations of the decode signal and the priority register.

FIG. 14 is a schematic explanatory diagram for explaining a clipping calculation method in the clipping calculation unit.

FIG. 15 is a block diagram illustrating a specific circuit configuration of the clipping operation unit.

FIGS. 16 (A), (B), (C) and (D) are schematic illustrations for explaining an improvement in processing speed by priority change and parallel connection.

FIG. 17 is a schematic explanatory diagram for explaining the concept of a conventional three-dimensional simulator device.

FIG. 18 is a schematic block diagram showing a configuration of a conventional three-dimensional simulator device.

FIG. 19 is a schematic explanatory diagram for describing an image processing operation in the image supply unit.

BEST MODE FOR CARRYING OUT THE INVENTION (Table of contents of the embodiment) 1.3 Description of the whole simulator device 2. Description of image supply unit (1) Initial setting (2) Transfer of frame data (3) Transfer of object data (4) Operation in coordinate conversion unit, etc. 3. Description of clipping processing device (1) Configuration and operation (2) Application example (3) Trivial clipping / reject 4. Specific example (1) Priority change unit, priority register, etc. 2) Clipping calculation unit (3) Improvement of processing speed by priority change and parallel connection 1.3 Overall description of 1.3D simulator First, the entire 3D simulator will be described.

As shown in FIG. 2, the present three-dimensional simulator apparatus includes an operation unit 412, a virtual three-dimensional space calculation unit 413, an image synthesis unit 401,
It includes RT446. Further, the image synthesizing unit 401 includes an image supply unit 410 and an image forming unit 428. In the following description, a case where the present three-dimensional simulator device is applied to a three-dimensional game will be described as an example.

In the virtual three-dimensional space calculation unit 413, a virtual three-dimensional space is set based on a game program stored in the central processing unit 414 and an operation signal from the operation unit 412. More specifically, virtual three-dimensional space setting information composed of position / direction information of three-dimensional objects (for example, enemy airplanes, mountains, buildings, etc.) constituting a virtual three-dimensional space, position / view direction information of a player, and the like. Is calculated and output to the image supply unit 410 in the image synthesis unit 401.

In the image supply unit 410, predetermined arithmetic processing is performed in accordance with the virtual three-dimensional space setting information. Specifically, arithmetic processing such as coordinate conversion from the absolute coordinate system to the viewpoint coordinate system, clipping processing, perspective projection conversion, sorting processing, and the like are performed, and data is output to the image format unit 428. In this case, the output data is expressed as data divided for each polygon, and specifically, is configured from vertex image information such as position coordinates, texture coordinates, and other accompanying information of each vertex of the polygon. . The image supply unit 41
Details of the configuration and operation of 0 will be described later.

The image forming unit 428 calculates image information inside the polygon based on the vertex image information given for each vertex of the polygon, and outputs this to the CRT 446.

In the three-dimensional simulator apparatus of the present embodiment, image synthesis is performed by a method called a texture mapping method and a Gouraud shading method in order to more efficiently synthesize a high-quality image. Hereinafter, the concepts of these techniques will be briefly described.

FIG. 3 shows the concept of the texture mapping method.

Conventionally, when an image is formed by combining, for example, a lattice-like or striped pattern on each surface of a three-dimensional object 332 as shown in FIG. )-(80) (3-dimensional polygon (41)-(80)
Are not shown), and image processing is performed on all of these polygons. The reason for this is that in the conventional three-dimensional simulator device, a color in one polygon can be painted only with one designated color. As a result, when synthesizing a high-quality image on which a complicated pattern or the like is applied, the number of polygons increases significantly. Therefore, it is practically impossible to synthesize such a high-quality image. It was possible.

Therefore, in the present three-dimensional simulator apparatus, processing such as rotation, translation, and perspective transformation of the three-dimensional object 332 and processing such as clipping are performed for each of the three-dimensional polygons A, B, and C constituting each surface (specifically, (Each vertex of each three-dimensional polygon), a lattice-like pattern, and a stripe-like pattern are treated as textures, and are processed separately from polygon processing. That is, as shown in FIG.
8 is provided with a texture information storage unit 442, in which texture information to be attached to each three-dimensional polygon,
That is, image information such as a lattice pattern or a stripe pattern is stored.

Then, the address of the texture information storage unit 442 specifying the texture information is given as the texture coordinates VTX and VTY of each vertex of each three-dimensional polygon. Specifically, as shown in FIG. 3, for each vertex of polygon A, (VTX0, VTY0), (VTX1, VTY1), (VTX2, VTY
2), (VTX3, VTY3) texture coordinates are set.

The processor unit 430 in the image forming unit 428 obtains the texture coordinates TX and TY for all the dots in the polygon from the texture coordinates VTX and VTY of each vertex.
Then, based on the determined texture coordinates TX and TY, the corresponding texture information is read from the texture information storage unit 442 and output to the pallet & mixer circuit 444.
This makes it possible to synthesize an image of a three-dimensional object on which a texture such as a lattice or a stripe is applied as shown in FIG.

Further, in the present three-dimensional simulator, the three-dimensional object 332 is represented as a cluster of three-dimensional polygons as described above. Therefore, the continuity of the luminance information at the boundary of each three-dimensional polygon becomes a problem. For example, when trying to represent a sphere using a plurality of three-dimensional polygons, 3
If all the dots in the three-dimensional polygon are set to the same luminance, a situation occurs in which the boundary of each three-dimensional polygon is not expressed as “roundness”, although the user actually wants to express “roundness”.
Therefore, the three-dimensional simulator avoids this by a method called Gouraud shading.
In this method, the luminance information VBRI0 to VBRI3 of each vertex is given to each vertex of the three-dimensional polygon as shown in FIG.
When the image is finally displayed in step 8, the luminance information V of each vertex
From BRI0 to VBRI3, luminance information for all dots in the three-dimensional polygon is obtained by interpolation.

As described above, the three-dimensional simulator apparatus is configured to perform high-quality and high-speed image processing using the texture mapping method and the Gouraud shading method. Thus, the image information of the polygon is configured as data in which a plurality of data such as vertex display coordinates, vertex texture coordinates, and vertex luminance information of the polygon are linked. Further, there are object data which is data common to the same three-dimensional object, and frame data which is data common within the same frame. FIG. 4 shows an example of these data formats. Therefore, the data that is divided into a plurality of pieces of data as shown in FIG.
One of the major technical issues is how to perform processing efficiently and properly.

Note that, in order to simplify the description, as shown in FIG.
Z3 is represented as X0 to Z3.

2. Description of Image Supply Unit The image supply unit 410 includes, as shown in FIG.
It includes a dimensional image information storage unit 416, a coordinate conversion unit 418, a clipping processing unit 420, an output format conversion unit 421, and a sorting processing unit 422.

Hereinafter, the configuration and operation of the image supply unit 410 will be described by taking, as an example, a case where the present three-dimensional simulator apparatus is applied to a driving game.

(1) Initial setting When the power of the present three-dimensional simulator is turned on, the virtual three-dimensional space calculation unit 413 (central processing unit 414) switches to the processing unit 41.
Through 5, image information of a three-dimensional object representing a racing car, a steering wheel, a road, and the like, which are components of the driving game, is written to the three-dimensional image information storage unit 416. The present three-dimensional simulator apparatus performs various image calculation processes such as coordinate conversion, rotation, and translation on the image information of the three-dimensional object to form a driving virtual three-dimensional space.

When the three-dimensional image information storage unit 416 is a ROM,
This writing is not required.

(2) Transfer of frame data Viewpoint information common to all three-dimensional objects, that is, information on a player's viewpoint position, angle, and viewing angle, monitor information, and the like is provided every field, for example, every (1/60) second. The updated data is transferred from the virtual three-dimensional space calculation unit 413 to the coordinate conversion unit 418 via the processing unit 415. The coordinate conversion unit 418 performs various coordinate conversions based on the data.

Also, information such as the angle and size of the monitor is transferred to the clipping processing device 420 as data for clipping processing. The clipping processing device 420 calculates a clipping plane or the like on which clipping processing is performed based on the data, and performs clipping processing.

These transferred data are called frame data, and are set at the head of each frame as shown in FIG.

(3) Transfer of Object Data In order to form a virtual three-dimensional space, a racing car, a steering wheel,
Various three-dimensional objects such as roads must be arranged at predetermined positions in a virtual three-dimensional space. Therefore, an object number and position information indicating which three-dimensional object is to be arranged and where is needed. These object numbers, position information, and the like are stored in a virtual three-dimensional space operation unit.
Transferred from 413 to the processing unit 415.

Next, using the object number as an address,
The image information of the corresponding three-dimensional object is read from the three-dimensional image information storage unit 416. That is, for example, when the object number designates a racing car, the image information of the racing car is read from the three-dimensional image information storage unit 416. In the three-dimensional image information storage unit 416, image information of a racing car or the like is represented and stored as a set (polyhedron) of a plurality of polygons. Processing unit
The data format forming unit 415 forms data called object data and polygon data from the read data by the data format forming unit 417, and sequentially transfers the data to the coordinate conversion unit 418 and below.

Here, the object data refers to data composed of position information, rotation information, other attached data, and the like of a racing car that is a three-dimensional object. The polygon data is data obtained by dividing the image information of the racing car into polygons, and is data composed of vertex coordinates, vertex texture coordinates, vertex luminance information, and other attached data of polygons. These data are sent to the next stage by the data format forming unit 417 in a data format as shown in FIG.

The object data includes data for setting a clipping plane for each object, as described later.

(4) Operation in Coordinate Conversion Unit and the Like The coordinate conversion unit 418 is based on the viewpoint information of the player transferred from the processing unit 415 and the object data including the racing car position information and the rotation information transferred from the processing unit 415. Next, various coordinate transformations are performed on the polygon data. That is, rotation of the polygon data in the local coordinate system, translation to the world coordinate system, rotation to the viewpoint coordinate system, and the like are performed.

The clipping processing device 420 performs a clipping process on the polygon data on which the coordinate conversion has been completed. The plane equation for performing the clipping process is calculated using the one transferred as the frame data as described above. The details of the clipping process will be described later.

The output format conversion unit 421 performs a process of format-converting a polygon transformed into a polygon by the clipping process into, for example, a quadrilateral polygon.
The format-converted data is output to the next-stage sorting processing unit 422.

3. Description of Clipping Processing Apparatus (1) Configuration and Operation As shown in FIG. 1, the clipping processing apparatus 420 according to the present embodiment includes a priority register (priority storage unit) 170 for storing index data of a clipping plane according to priority. A reading unit 190 for reading index data from the priority register 170, a priority changing unit 160 for changing data of the priority register 170, a selector 150, a selector
An initial value setting unit 152 that sets an initial value in a priority register from data input from 150, a control unit 154 that performs overall control, and a clipping operation unit 200 are included.

In the clipping operation unit 200, actual clipping processing and perspective projection conversion are performed. Specifically, FIG.
As shown in FIG. 5, for each of the clipping planes 1 to 6, for each of the polygons constituting the three-dimensional objects 300, 333, and 334, an inside / outside determination is made as to whether the polygon is inside or outside the display area 20. Will be

For example, since all the polygons forming the three-dimensional object 334 are completely outside the display area 20, these pieces of image information are removed from data to be subjected to subsequent image processing. Since all the polygons of the three-dimensional object 300 are within the display area 20, these pieces of image information are used as they are for subsequent image processing. Further, in the three-dimensional object 333 at the boundary of the display area 20, the part outside the display area 20 is removed, and only the part inside the display area 20 is used for the subsequent image processing. In this case, a point internally divided by the boundary is calculated, thereby forming new polygon data.

Finally, the perspective projection transformation to the screen coordinate system (XS, YS) is performed only on the object within the display area 20,
Data is sent to the next stage. In this case, since the clipping process and the perspective projection transformation are mathematically similar computation processes, the clipping computation unit 200 is configured to perform the clipping process and the perspective projection transformation with exactly the same configuration.

By the way, the clipping processing device 420 according to the present embodiment,
The clipping processing and the perspective projection conversion using the plurality of clipping planes are configured to be performed by one or a plurality of clipping processing apparatuses.

The connections shown in FIG. 1 and FIG. 5 show connections in the case where clipping processing and perspective projection conversion are performed on all clipping planes by only one clipping processing device 420. In the case of such a connection configuration, the clipping processing device 420 operates as follows.

That is, as shown in FIG. 6A, after outputting the processed data, new data is input, and the clipping process is performed on the clipping plane to be performed first. Thereafter, the input and output are connected to form an inner loop as shown in FIG. As a result, the data clipped by the first clipping plane is returned to the input, and the returned data is subjected to clipping processing by the next clipping plane.

In this way, after the clipping process is sequentially performed in accordance with the predetermined order of the clipping plane, finally, the perspective projection conversion is performed, the inner loop is released, and the data is transmitted to the output format conversion unit 421 in the next stage. Is output.

Hereinafter, the mode in which the inner loop is formed and the previously processed data is returned to the input and the clipping process and the perspective projection conversion are sequentially performed is referred to as a reentrant mode.

FIG. 6C shows an example in which the clipping processing device is provided in a plurality of stages and the above processing is performed. In this case, for example, in the first-stage clipping processing device 420a, the clipping process using the first three clipping surfaces is performed, and in the second-stage clipping processing device 420b,
The clipping process and perspective projection conversion of the remaining three surfaces are performed. In this way, the clipping devices are connected in series,
If processing between the respective clipping processing devices is performed by pipeline processing, the clipping processing speed can be greatly improved. However, in this case, since the number of clipping processing devices increases, it is advantageous to perform clipping processing with only one clipping processing device in terms of hardware saving.

The priority register 170 stores data for specifying the order of the clipping planes in which the clipping process is performed in the clipping processing device. Specifically, index data that specifies a clipping plane on which clipping processing is performed is stored in the processing order.

The initial value setting unit 152 sets an initial value in the priority register 170. The setting of the initial value is performed by initial mode designation data and priority designation data selected and input by the selector 150. . Here, the initial mode designation data is data set when the entire three-dimensional simulator device is reset. Further, the priority designation data is included in the object data shown in FIG. 4, and thereby, it is possible to designate the priority of the clipping plane in units of three-dimensional objects.

FIG. 7A shows an example of the initial mode designation data and the priority designation data. This data is
For example, it is composed of 8-bit data. Bits 0 to 6 are used to specify a clipping plane, and bit 7 is used to specify whether or not to perform perspective projection conversion. When each bit is '0', it means that no designation is made, and when each bit is '1', it means that designation is made. Further, the order of the clipping process and the perspective projection conversion process is specified to be performed in order from the LSB of the bit shown in FIG.

Thus, when the initial mode designation data is set as shown in FIG. 7A, bits 1, 2, 3, 7
Is '1', which means that clipping processing is performed in the order of clipping planes 1, 2, and 3, and then perspective projection conversion is performed and output.

As shown in FIG. 19, the clipping process in the three-dimensional space is actually sufficient if there are at most six clipping planes. However, in the present embodiment, as shown in FIG. 7A, the clipping processing for up to seven surfaces can be performed. This is effective, for example, when the present three-dimensional simulator apparatus is applied to a game or the like and a video effect such as the disappearance of a game character on a wall or the like. In other words, by setting the remaining clipping plane on this wall or the like, it is possible to produce a video effect such that the character disappears or slips through this wall.

When the power of the three-dimensional simulator is turned on, initial mode designation data is input to the initial value setting unit 152. Then, for example, when the initial mode designation data is data having the contents shown in FIG. 7A, the priority register 170 uses the initial value setting unit 152 to set the initial state (1, 2) as shown in FIG. , 3 and 7). As a result, the clipping process is performed on the first polygon in the order of the clipping planes 1, 2, and 3, and finally the perspective projection conversion is performed.

Here, it is assumed that a clip-out for a certain polygon has occurred on the clipping plane 2. Then, the processing by the clipping processing device 420 is interrupted, and the data written in the priority register 170 is changed by the priority changing unit 160. More specifically, as shown in FIG. 7 (C), the contents of the priority register 170 are such that the clipping plane 2 comes first, and the processing order of the clipping plane 1 is lowered by one. , 1, 3, and 7 are changed in this order. As a result, the subsequent clipping processing for the polygon is performed in the order of the clipping planes 2, 1, and 3.

Next, when clipping out occurs on the clipping plane 3, the contents of the priority register 170 are changed as shown in FIG.
Are changed in the order of 3, 2, 1, and 7.

When the clipping process for all the polygons constituting the three-dimensional object is completed in this manner, the priority designation data corresponding to the next three-dimensional object to be processed is stored in the priority register 170 via the initial value setting unit 152. Is set. However, the setting of the initial value for each three-dimensional object by the priority designation data is arbitrary, and it is not always necessary to set this for each three-dimensional object. If not set, the subsequent polygon clipping processing is performed according to the contents of the priority register 170 set last.

This priority designation data is included in the object data, and specifically, is shown in FIG.
The three-dimensional object is stored in the three-dimensional image information storage unit 416 as accompanying data for each three-dimensional object. The priority designation data is set in advance by a program for forming a virtual three-dimensional space, for example.
That is, the place to be arranged in the virtual three-dimensional space is determined to some extent. Therefore, if this priority designation data is set for a three-dimensional object in which the clipping plane to be clipped can be expected to some extent, the clipping processing speed Can be greatly improved.

(2) Example of Application Now, in the present embodiment, the speed of the clipping process is greatly increased by the above-described method. Hereinafter, it will be described how this method is effective in increasing the speed of the clipping process, as shown in FIG. This will be described with reference to A) to (D).

FIGS. 8 (A) to 8 (D) show 2
An example in which clipping processing is performed in a dimensional space is shown. In the figure, an area surrounded by the clipping planes 1 to 4 is referred to as a display area 20. vice versa,
An area outside the display area 20 is referred to as a non-display area 18. Further, an area on the boundary between the clipping planes 1 to 4 is referred to as a boundary area 19.

At this time, first, consider a case where the clipping process is performed on the polygon 32 forming the three-dimensional object 30 in the order of the clipping planes 1, 2, 3, and 4 in FIG. In this case, clipping planes 1, 2,
In the clipping process of No. 3, since all the vertices of the polygon 32 are determined to be in the display area 20, the clipping is not performed depending on these clipping planes. Therefore, in this case, three unit times are required so far. However, on the next clipping plane 4,
Since it is determined that all the vertices of the polygon 32 are in the non-display area 18, the polygon 32 is clipped out. As a result, the clipping process eventually required four unit times.

However, the processing actually required here is only the processing for the last clipping plane 4, and all subsequent processing is useless. Therefore, how to reduce this useless processing becomes an issue.

By the way, an object (a three-dimensional object) has a certain size as a general property, and polygons constituting the same three-dimensional object are statistically “close”.
It can be said that there is. In other words, if one polygon forming the three-dimensional object clips out on a certain clipping plane, the other polygons forming the same three-dimensional object have a high probability of clipping out on the clipping plane. it can.
Therefore, when a certain polygon is clipped out on the clipping plane 4, the processing time of other polygons in the same object can be statistically reduced by performing clipping processing from the clipping plane.

This method is based on the arrangement of the three-dimensional object 30 in FIG.
When applied to the arrangement shown in FIG. When the polygon 32 is clipped out by the clipping plane 4, the contents of the priority register 170 are changed in the order of 4, 1, 2, 3, and 7, as shown in FIG. Therefore, the clipping processing of the next polygon 34 starts from the clipping plane 4 and is clipped out first. Therefore, three unit times are saved. Similarly, for the polygons 36 and 38, three unit times are saved. As a result, the processing time of the first polygon 32 is not different from the case where this method is not used, but the processing time of the second and subsequent polygons 32 to 38 is completely wasteful and becomes one unit time. Therefore, when the number of polygons is sufficiently large, the processing time required for the three-dimensional object 30 is reduced to about 1/4 compared with the case where this method is not used.

When this method is applied to the case where the arrangement of the three-dimensional object 40 is the arrangement shown in FIG. 8C, the following is obtained. When the polygon 42 is clipped out by the clipping plane 4, the contents of the priority register 170 are changed so that the order of the clipping planes to be processed becomes 4, 1, 2, 3 as shown in FIG. You.

Next, for example, if the clipping process of the polygon 44 is performed, the polygon 44 is not clipped out by the clipping surface 4 but clipped out by the clipping surface 2. Therefore, priority register 17
The contents of 0 are changed in the order of 2, 4, 1, and 3. In this case, the clipping plane 4 previously clipped out is moved down by one rank. Then, for example, if the clipping processing of the polygon 46 is performed, the clipping cannot be performed by the clipping plane 2, but can be clipped by the clipping plane 4 stored in the next order in the priority register 170. Accordingly, although processing cannot be performed in the shortest one unit time, processing can be performed in two unit times, thereby saving processing time.

In this embodiment, as described above, the optimal clipping plane order is determined in advance for each three-dimensional object.
Initial setting can be made by priority designation data. That is, for example, it is assumed that the three-dimensional object 40 illustrated in FIG. 8C has a high possibility of being clipped out by the clipping planes 4 and 2 due to the configuration of the formed virtual three-dimensional space. In this case, the priority designation data in the object data of the three-dimensional object 40 is changed to the processing order of the clipping plane, for example, 4,
By designating the polygons to be 2, 1, and 3, it is possible to save the processing time required when processing the polygon 42.

Further, the processing time can be saved by the present method is not limited to the case where the clipping process is continuously performed on polygons in the same three-dimensional object.
For example, the present method is also effective in saving processing time, even when the order of performing image processing is set in advance by a game program or the like so that the three-dimensional objects are located in as close order as possible. Specifically, for example, in FIG. 8E, a game program or the like is set to perform processing in the order of the three-dimensional objects 60, 62, and 64 that are close to each other. Accordingly, the data format shown in FIG. 4 formed by the data format forming unit 417 is formed so as to be in the order of the three-dimensional objects 60, 62, and 64. By doing so, if the three-dimensional object 60 is clipped out to the clipping plane 4 first, the possibility that the three-dimensional object 60 that should be near the clipping plane 4 is clipped out by the clipping plane 4 increases. This makes it possible to save processing time.

(3) Trivial Accept / Reject Now, in the above-described method, if all the polygons 52 to 58 are in the display area 20 like the three-dimensional object 50 shown in FIG. On the other hand, a processing time of 4 unit time is required.

In this case, the trivial accept
This can be dealt with by combining a reject method (hereinafter, referred to as a trivial clipping process) with the above method.

FIG. 9 shows a configuration diagram when this trivial clipping process is used. As shown in the drawing, when the trivial clipping process is performed, the configuration of the present embodiment has a configuration in which a preprocessing unit 280 is further included in the configuration of FIG.

The preprocessing unit 280 includes a preprocessing determination unit 282 that performs an inside / outside determination based on a trivial clipping plane, and a designation data generation unit 284 that forms designation data to be output to the initial value setting unit 152 based on the determination result. Be composed.

Next, the operation of the preprocessing unit 280 will be described with reference to FIG. It should be noted that FIG.
An application example in a dimensional space is shown.

First, in the preprocessing determination unit 282, the coordinate value of the representative point of the three-dimensional object 50 and the object length L are read. As the coordinates of the representative point, for example, an average value of the vertex coordinates of the three-dimensional object is used. Also, the object length L
For example, among the lengths between the vertices of the three-dimensional object, the maximum length is used. The representative point and the object length L are set as a part of the object data shown in FIG.

With this setting, the three-dimensional object 50 is simulated as a circle having a center coordinate of the representative value and a diameter L (a sphere in a three-dimensional space).

Next, the preprocessing determination unit 282 sets a zone for trivial clipping formed by the trivial clipping surfaces 11 to 14 and 21 to 24 (shaded portion in FIG. 10). Then, the three-dimensional object 50 imitated by the circle (sphere) includes a boundary area 27 which is an area on the zone, a display area 26 which is an inner area surrounded by the zone, and a display which is an area outside the zone. It is determined which of the outer regions 28 is located.
Here, the trivial clipping planes 11 to 14 are clipping planes set inside the clipping planes 1 to 4 by the maximum length ML, and the trivial clipping planes 21 to 24 are
This is a clipping plane set outside the clipping planes 1 to 4 by the maximum length ML. Note that the maximum length ML refers to the maximum value of the object length L of all three-dimensional objects.

By this inside / outside determination, for example, it is determined that the three-dimensional object 50 in FIG. 10 is in the display area 26, and the polygons 52 to 58 constituting this are determined to be in the display area 26 and do not need the clipping process. . Therefore, in this case, the designated data generating unit 284 forms designated data (for example, data which becomes '10000000' in FIG. 7A) that performs only perspective projection conversion and does not perform clipping, and sets the initial value. It is output to the unit 152. The initial value setting unit 152 sets the initial value of the process for the three-dimensional object 50 in the priority register 170 based on the specified data. As a result,
The data of the polygons 52 to 58 are output after only the perspective projection conversion is performed in the clipping calculation unit 200.

Similarly, the three-dimensional object 30 is determined to be in the non-display area 28 by the inside / outside determination, and the polygons 32 to 38 are determined to be in the non-display area 28 and do not require clipping processing. Therefore, in this case, the designated data generating unit 284 designates the designated data for which neither the perspective projection conversion nor the clipping process is performed (for example, '00 in FIG. 7A).
000000 ') is output to the initial value setting unit 152. With this designation data, the initial value of the process for the three-dimensional object 30 is set in the priority register 170. As a result, the data of the polygons 32 to 38 are not subjected to any processing in the clipping operation unit 200.

Similarly, the three-dimensional object 40 is determined to be in the boundary area 27 by the inside / outside determination, and the polygons 42 to 48 are determined to require clipping processing. In this case, no designated data is formed in the designated data generating unit 284. Therefore, the clipping process for the polygons 42 to 48 is efficiently performed by the above-described method of sequentially changing the priority.

As described above, in the present embodiment, a very efficient clipping process can be performed by combining the method of sequentially changing the priority and the method of performing the trivial clipping process. That is, the preprocessing unit 280
Since only the perspective projection conversion needs to be performed on the polygon determined to be in the display area 26 by the rough inside / outside determination, the processing is completed in only one unit time. Further, no processing is required for the polygons that are determined to be in the non-display area 28, so that the processing time is only the processing time required for the pre-processing. In addition, for the polygons that are determined to be in the boundary area 27, most of the polygons are processed in 1-2 unit time except for the polygons that are processed first by the above-described method of sequentially changing the priority. Processing can be performed.

4. Specific Examples (1) Priority Change Unit, Priority Register, etc. FIG. 11 shows a specific circuit configuration of the priority register 170, and FIG. Detailed connection status is shown.

As shown in FIG. 11, the priority register 170
It comprises eight 3-bit registers 171 to 178 for storing the priority of the clipping plane, and OR circuits 181 to 188 for permitting data writing to these registers.

As shown in the figure, the registers 171 to 178 are serially connected, are clock-driven by a CLK signal, and are reset at power-on by a RES signal. The input data DIN [2: 0] is input to the first register 171.

Next, the select signal SA input to the terminal SA of the register
When any of [7: 0] is asserted, the terminal DA is selected as input data of the corresponding register. As a result, the output data of the preceding register is loaded into the register, and the data is shifted. vice versa,
When the select signal SA [7: 0] input to the terminal SA is negated, the terminal DB is selected as input data of the register. As a result, the own output data is fed back and input to the register as it is, and the register holds the previous data as it is.

Here, the assertion means a signal state in which a terminal is turned on, and the negation means a signal state in which a terminal is turned off.

The enable signals ENALL input from the control unit 154 and the load signals ENL [7: 0] input from the priority change unit 160 are connected to the OR circuits 181 to 188. When the enable signal ENALL is asserted, the input of the load signal ENL [7: 0] is prohibited, and all the registers 171 to 178 are shifted. Conversely, when the enable signal ENALL is negated, the input of the load signal ENL [7: 0] is enabled.

The priority change unit 160 includes a counter 162, a decoder
164, an AND circuit 166, and a selector 168.

The counter 162 is a 3-bit synchronous counter.
Clocked by the LK signal and reset at power-on by the RES signal. Then, the count enable signal COEN
Is asserted, it is counted up by the next CLK signal. When the clear permission signal CLEN is asserted, it is cleared in synchronization with the next CLK signal.

The counter 162 stores how many times the clipping process is currently performed in the reentrant mode. For example, the following is an example of a clipping processing device 420a that performs clipping processing on three surfaces in the connection state shown in FIG. 6C. That is, when polygon data to be processed is newly input, the data stored in the counter 162 is (000),
In this state, the first clipping process is performed on the polygon data. When the first clipping process is completed, the count permission signal COEN input from the control unit 154 is asserted, and the data stored in the counter 162 becomes (001). Similarly, when the second clipping process ends, the stored data becomes (010), and the third clipping process is performed in this state. Finally, when the third processing is completed, the clear permission signal CLEN is asserted, and the stored data is cleared to (000) again.

By the above operation, the counter 162 plays the following two roles. The first role is to specify a clipping plane (or perspective projection conversion mode) for which clip processing is to be performed at present. That is, the output of the counter 162 is input to the reading unit 190 as a 3-bit read code REC [2: 0]. Then, the priority reading unit 190 uses the read code REC [2: 0] to select one of the outputs Q0 to Q7 of the priority register 170.
Select what should be the clipping plane designation data SAD [2: 0]. Thereby, the clipping operation unit at the subsequent stage
Index data specifying the clipping plane (or perspective projection conversion mode) for which clipping processing is to be performed at present is output to 200.

The second role of the counter 162 is to generate a signal for rewriting the priority register 170 when clipout occurs. Specifically, counter 16
The output of 2 is input to the decoder 164 as shown in FIG.
Then, in the decoder 164, the 3
An 8-bit write code WRC [7: 0] as shown in FIG. 13A is generated from the bit data. The write code WRC [7: 0] is supplied to the load signal ENL via the AND circuit 166.
[7: 0] is input to the priority register 170. In the priority register, this load signal ENL
[7: 0] determines which register is to be rewritten.

The selector 168 controls the initial value input from the initial value setting unit 152 or the reading unit 190 under the control of the control unit 154.
Plane specification data SAD [2: 0] output from
(Specifically, data for specifying a clipped plane clipped out) has a function of selecting one of them.

Next, the operation of these circuits will be described with reference to FIGS.

(A) Initialization First, in the initial state, that is, at the time of turning on the power or at the start of processing for each three-dimensional object, the initial value setting unit 15
2 is input with initial mode designation data (when power is turned on) or priority designation data (when starting three-dimensional object processing). At this time, for example, as shown in FIG. 13B, data (10101110) is stored in the initial value setting unit 152.
Is entered. This means clipping plane 1,
Perform clipping processing on 2, 3, and 5, and then
This means that perspective projection conversion (7) is performed and output. The initial value setting unit 152 encodes this data into a 3-bit value and outputs the value to the selector 168. Specifically (111),
The values of (101), (011), (010), (001), ie 7,
It is encoded into a 3-bit code representing 5, 3, 2, 1.

In the selector 168, according to a control signal from the control unit 154,
Terminal B is selected, and the encoded data is input. In this case, the enable signals of all the signals from the control unit 154 are ENALL = 0. Therefore,
As described above, all the registers 171 to 178 in the priority register 170 are in the shift state. As a result, the data from the selector 168 is sequentially shifted and input to the registers 171 to 178. Then, in this example, '1' is stored in the register 171 and '2' is stored in the register 172.
Is '3' in register 173, '5' in register 174,
'7' is set in 175, and the registers 176 to 178 are in an undetermined state.

(B) Normal operation After the above initial settings are completed, the clipping process is started. During normal operation, ENMASK = 0, ENALL =
It is 1. As a result, the write code WRC [7: 0]
Are all masked and the load signal is ENL [7: 0]
Are all '0', and therefore the selector signal SA [7:
0] are all '0'. As a result, the registers 171 to 178 are all in the holding state, and the data of “12357” is held.

Next, the read code REC output from the counter 162
[2: 0] are sequentially counted up. As a result, in the reading unit 190, the outputs Q7 to Q1 of the priority register 170 are sequentially selected. As a result, in this example, clipping processing is performed in the order of the clipping planes 1, 2, 3, and 5, and finally Perspective projection transformation (7) is performed.

(C) When Clipout Occurs It is assumed that a polygon is clipped out on the clipping plane 3 during the normal operation described above.
Then, the control unit 154 sets EMASK = 1, and the AND circuit
166 becomes conductive, and the load signal ENL [7: 0] up to the clipping plane where the clipping process is currently being performed is asserted. Specifically, as shown in FIG. 13 (C), ENL [7]
~ ENL [5] becomes '1'. As a result, registers 171 to 17
3 is in the shift state, and the registers 174 to 178 are in the holding state.

Then, the selector 168 selects the terminal A, and the register 173 storing the instruction data of the clipping plane 3 is stored.
Are connected to the first-stage register 171 via the selector 168 as shown in FIG.

Then, since the registers 171 to 173 are shifted by the next clock, the order of the data stored in the registers 171 to 173 is changed from "1", 2 "3" to "3" as shown in FIG. 1''2 '
Is changed to That is, the data indicating the clipping plane on which the clipping process is currently being performed is stored in the first-stage register. The reduced instruction data will be loaded.

It should be noted that since the perspective projection conversion process must be performed after all clipping processes have been completed, EMASK = 0 during the perspective projection conversion process, and the contents of the priority register 170 are not updated.

By the above operation, for example, when a certain polygon is clipped out on the clipping plane 3, the next polygon is processed from the clipping plane 3, and the speeding up of the clipping processing can be greatly improved. In this case, the order of the clipping planes is reduced by one. Thus, for example, a clipping plane that previously had a clipping out will only move down to the second order. As a result, even if it is not clipped out by the topmost clipping plane,
Since the possibility of clipping out by the next-ranked clipping plane increases, clipping processing can be speeded up and optimized.

(2) Clipping Operation Unit Next, a specific configuration and operation of the clipping operation unit 200 will be described.

First, a method of the clipping process in the present embodiment will be described below with reference to FIG. FIG. 14 shows a case where the polygon 70 is clipped by the clipping plane 1. In the figure, v0 = (X0, Y0, Z0), v1 = (X
1, Y1, Z1), v2 = (X2, Y2, Z2), v3 = (X3, Y3, Z
3) is the vertex coordinates of the polygon 10, and h (V) = aX + b
X + cZ + d is a plane equation of the clipping plane 1.

(A) Judgment of inside / outside of each vertex coordinate At the same time as the input of the polygon data, inside / outside judgment as to whether the vertex coordinates V0 to V3 are in the area outside or inside the clipping plane 1 is performed. For this purpose, first, the following calculation is performed.

h (V0) = aX0 + bY0 + cZ0 + dh (V1) = aX1 + bY1 + cZ1 + dh (V2) = aX2 + bY2 + cZ2 + dh (V3) = aX3 + bY3 + cZ3 + d By the above operation, if h (Vn) .ltoreq.0, it is determined that h (Vn) .ltoreq.0 if the above-mentioned operation indicates that V (n) ≤0. If h (Vn)> 0, it is determined that Vn is in the non-display area. For example, in FIG. 14, since h (V0) and h (V3)> 0, it is determined that V0 and V3 are in the non-display area, and V (V1), h (V2) ≦ 0,
1, V2 is determined to be in the display area.

(B) Calculation of Internal Dividing Points In FIG. 14, for the polygon 72 for which all vertices are determined to be in the display area, all vertices are directly subjected to the next processing (for example, clipping processing or perspective projection conversion for the next plane). Will be done. For the polygon 74 for which all vertices are determined to be in the non-display area, all vertices are excluded from the target of the next processing.

On the other hand, for the polygon 70 clipped by the clipping plane 1, clipping points, that is, internally dividing points Vk and Vl are obtained. Then, the vertices V0 and V3 are excluded from the target of the subsequent processing. Instead, the internally dividing points Vk and Vl are set as the vertices of the polygon 70, and are used for the subsequent processing.

In order to obtain the internal dividing points Vk and Vl, first, the respective internal dividing ratios tk and tl are obtained by the following arithmetic expressions.

tk (| h (V0) |) / (| h (V1) -h (V0) |) tl (| h (V2) |) / (| h (V3) -h (V2) |) Using the internal division ratios tk and tl, the internal division points Vk and Vl are obtained by the following arithmetic expressions.

Vk = V0 + tk (V1−V0) Vl = V2 + tl (V3−V2) All the calculations of the above-mentioned inner dividing points have been described using the example of the inner dividing point calculation of the vertex coordinates. For the texture coordinates and vertex luminance information, the subdivision point is obtained by clipping. In the above description, the number of vertices of a polygon has been described by taking a polygon having four vertices as an example. However, the present invention is not limited to this, and a clipping process can be performed on a polygon having any n vertices. . Therefore, in this case, the above-mentioned arithmetic expression can be represented by the following general expression, and the output data Wout is obtained thereby.

Wout = Wa + ti (Wb−Wa) W: vertex luminance coordinates I0 to In, vertex texture coordinates TX0, T
Y0 to TXn, TYn, vertex coordinates X0, Y0, Z0 to Xn, Yn, and Zn which are clipped a, b: Point number between two points to be clipped ti: Internal division ratio at that time In the clipping processing device of the example, the data to be directly used for the next processing without performing the clipping processing is calculated by setting ti = 0 in the above equation.

Further, in the clipping processing device of the present embodiment, the processing is speeded up by performing pipeline processing of (A) the inside / outside determination and (B) the calculation of the inner dividing point.

(C) Configuration and Operation of Clipping Calculation Unit The clipping calculation unit 200 includes an inside / outside determination unit 210, an inside division point calculation unit 230, and an output multiplexer 260 as shown in FIG.

In the present embodiment, the calculation process in the inside / outside determination unit 210,
The arithmetic processing in the internally dividing point arithmetic unit 230 is performed by pipeline processing. The inside / outside determination section 210 performs an inside / outside determination operation on the input polygon data sequentially, and is controlled so that the latest data to be subjected to the inside division point calculation section 230 is always sent to the inside division point calculation section 230. The reason for using such a control method is as follows. That is, in this type of three-dimensional simulator device, the number of polygons for which the internal dividing point calculation is to be performed usually changes depending on the operation state of the player. On the other hand, since the internal division operation unit 230 performs an operation such as division, more operation processing time is required as compared with the internal / external determination unit 210. Therefore, in order to perform the arithmetic processing at the optimum speed in such a situation, it is necessary that the inside / outside determination unit 210 is always controlled so that the latest data can be output to the internal dividing point calculation unit 230. Become.

Further, the clipping processing device 420 according to the present embodiment,
With the reentrant mode described above, one clipping processing device 420 can perform clipping processing using a plurality of clipping planes. In this case, the output multiplexer 260 re-inputs the clipped polygon data to the input unit 212,
Clipping processing using a plurality of clipping planes can be performed on the same polygon data.

The inside / outside determination unit 210 includes an input unit 212, a polygon data register 214, a plane equation calculation unit 216, and a clipping instruction unit 218.
It is comprised including.

In the input unit 212, from the frame data, object data, and polygon data input from the coordinate transformation unit 418,
The clipping calculation unit 200 extracts necessary data and performs various data format conversions.

For example, the angle, size, and the like of a monitor that displays an image are extracted from the frame data, and the coefficients and the like of a plane equation for performing clipping are extracted. Further, data necessary for processing for each object is extracted from the object data. Also, from the polygon data, the vertex coordinates, vertex texture coordinates, vertex luminance information, etc. of the polygon are extracted, and the necessary data format conversion is performed.
The vertex coordinates are output to the plane equation calculation unit 216, and the vertex coordinates, the vertex texture coordinates, the vertex luminance information, and the like are output to the polygon data register 214.

The polygon data register 214 sequentially stores the vertex coordinates, vertex texture coordinates, vertex luminance information, and the like input from the input unit 212 and, according to the instruction of the clipping instructing unit 218, converts the data into the internal dividing point calculating unit 230 or the output multiplexer. Output to 260.

In the plane equation calculation unit 216, as described in the calculation method, the inside / outside determination is performed on the full-length point coordinates vn of the polygon according to the following calculation formula. Where the coefficients a, b,
c and d are set by the frame data.
Also, which clipping plane is to be operated by the plane equation, that is, which clipping plane is to be operated in order is determined by the data read by the reading unit 190.

h (Vn) = aXn + bYn + cZn + d If the above operation results in h (vn) ≦ 0, vn
Is determined to be in the display area, and when h (vn)> 0, vn is determined to be in the non-display area.

The clipping instructing unit 218 stores the index data of each vertex of the polygon in the display area or the non-display area. Then, when all the vertices of the polygon are determined to be in the non-display area, the polygon data register 214 is instructed to invalidate the polygon data.

If all vertices are in the display area,
Instruct the polygon data register 214 to output the polygon data to the output multiplexer.

If it is determined that the polygon is in the boundary area of the clipping plane, that is, if it is determined that the polygon is internally divided by the clipping plane, the polygon data is output to the polygon data register 214 and to the internal division point calculation unit 230. To instruct. In this case, the clipping instructing unit 218 calculates h (Vm) and h (Vn) (hereinafter, h (Vn)) calculated by the plane equation calculating unit 216.
hm, hn) to the internally dividing point calculation unit 230.

The clipping instructing unit 218 also generates data necessary for data control and the like in the internally dividing point calculating unit 230. Further, when the current mode is a mode for performing perspective projection conversion, various instructions are given so that the calculation in the internally dividing point calculation unit 230 is a perspective projection conversion calculation.

The internal dividing point calculation unit 230 includes absolute value calculation units 232 and 234, selectors 236 and 238, division unit 240, subtraction unit 242, 0 mask unit 244,
It is configured to include one mask unit 246, multiplication unit 248, and addition unit 250.

In the absolute value calculation units 232 and 234, | hm−hn | and | hm are respectively obtained from hm and hn output from the clipping instruction unit 218.
Is calculated and output to the division unit 240 via the selectors 236 and 238. The division unit 240 calculates the internal division ratio ti = | hm | / | hm-hn | from these data, and outputs the result to the multiplication unit 248.

The subtraction unit 242 calculates Wb−Wa from the polygon data Wa and Wb output from the polygon data register 214 and outputs the result to the multiplication unit 248. Here, Wa and Wb include not only vertex coordinates of the polygon but also vertex texture coordinates and vertex luminance information. This is because these data are necessary for the later image processing calculation when the polygon is internally divided.

The multiplication unit 248 calculates ti (Wb−Wb) from the ti and Wb−Wa.
a) is calculated and output to the adder 250.

The adder 250 calculates Wout = Wa + ti (Wb-Wa) from Wa and the ti (Wb-Wa). This means that the internal dividing point has been obtained.

In addition, the internally dividing point calculation unit 230 can perform not only the internally dividing point calculation but also the perspective projection conversion calculation. In this case, Wa and h are respectively selected by the selectors 236 and 238, and the data is masked by the 0 mask unit 244 and the 1 mask unit 246, respectively, and '0' and '1' are set.
As a result, the above arithmetic expressions are expressed as Wa = 0, Wb-Wa = 1, ti
= H / Wa, and Wout = h / Wa is calculated, whereby the perspective projection transformation is performed. As described above, in the present embodiment, the perspective projection conversion can be performed together by using the circuit configuration for performing the internal dividing point calculation. Therefore, it is not necessary to newly provide a circuit for performing the perspective projection conversion, and it is possible to greatly reduce hardware. In particular, it is advantageous in that a large-scale circuit such as the division unit 240 can be used together.

The calculation result Wout in the internal dividing point calculation unit 230 is input to the output multiplexer 260. The output multiplexer 260 returns the operation result to the input unit when the clipping process by another clipping plane for the polygon still remains. This operation is repeated until the processing of all clipping planes stored in the priority register and the perspective projection conversion are completed. Then, when the processing of the last clipping plane or the perspective projection conversion is completed, the data is output to the output format unit 421 at the next stage.

(3) Improvement of Processing Speed by Changing Priority and Parallel Connection FIG. 16A shows a case where a clipping process is performed by a conventional clipping device. That is, in the related art, the clipping process is performed by connecting five clipping processing devices 400a to 400e and the perspective projection conversion circuit 402 in series (in the case of clipping by five planes). The processing time in this case is hereinafter referred to as one unit time.

On the other hand, in the clipping processing device according to the present embodiment, it is possible to process this with one clipping processing device 420 as shown in FIG. Further, as shown in FIG. 4C, depending on the situation of the screen to be synthesized, a plurality of, for example, two clipping processing units 42 may be used.
It is also possible to process by 0a and 420b. Hereinafter, it will be described how the clipping processing apparatus according to the present embodiment is effective for improving the speed.

Now, in the clipping processing device according to the present embodiment, as shown in FIG.
To 420f can be connected in parallel, so that the polygon data can be processed in parallel. Even with such a connection, the processing can be performed by the same number of clipping processing devices as the number of clipping processing devices required for the conventional clipping process in FIG.

With the configuration shown in FIG.
By using the reject method, for example, when it is determined that all polygons need only perspective projection transformation without clipping, clipping processing can be performed at six times the speed of the related art. In addition, even when the state is not ideal, as described below, this connection configuration is very effective in improving the processing speed.

For example, when the present three-dimensional simulator apparatus is applied to a game, the clipping processing of polygons during the game does not have to be performed for all clipping planes for all polygons. The ratio changes depending on the state of the screen. For example, the ratio is as follows.

No need for clipping 70% One-side clipping required 20% Two-side clipping required 8% Three or more clipping required 2% Now, in this case, the approximate time required for clipping is as follows: Show. In other words, the time required for the clipping process is calculated as
P0 (no clipping required, only perspective projection transformation)
PP5 (necessary 5 plane clipping processing, including perspective projection transformation) can be expressed by the following equation.

1 × P0 + 2P1 + 3P2 + 6P5 (k) For simplicity, clipping on three or more surfaces is assumed to be clipped on all five surfaces.

Here, substituting the typical ratio mentioned above,
(K) is 1 × 0.7 + 2 × 0.2 + 0.08 + 6 × 0.02 = 1.46. If this is distributed to the six clipping processors connected in parallel, the result is 1.46 / 6 = 0.233. Since the conventional clipping processing apparatus shown in FIG. 16A requires one unit time, the processing speed is increased by about 4.1 times.

It should be noted that the number of clipping processing devices has not changed compared to FIG. This speed is made possible by dynamically changing the contents of the polygon clipping process. However, in an extreme case, for example, when all the polygons need to be clipped, there is no difference in speed as compared with FIG.

However, even in such a case, the processing speed can be prevented from lowering by the above-described function of internally changing the priority of the clipping surface. Hereinafter, this will be described.

Clipping process is 3 for all polygons
Suppose you need a surface. This is true even when one three-dimensional object composed of a plurality of polygons becomes like this. In this case, as it is, the processing requires four loops (including perspective projection conversion), and FIG.
The processing speed is improved only by 6/4 = 1.5 times as compared with (A). However, at this time, it is assumed that 95% of the processed polygons are actually clipped out on one surface. This frequently occurs when the clipping process is actually performed. It is assumed that polygons to be clipped out first are arranged as conditions, and polygons to be clipped out are arranged subsequently.

In this case, the first polygon clipped out is 4
Twice the time is required. However, the subsequent polygons are processed first on the clipped-out clipping plane by using the above-described method of changing the priority, so that clipping occurs immediately, so that only one unit time is required. The processing time in this case is 0.05 × 4 + 0.95 × 1 = 1.15, assuming that the number of polygons is sufficiently large. This is 4 / 1.15 = 3.4 times when the priority of the clipping plane is not changed, and 1.5 × 3.4 = 5.1 (times) as compared with the case of FIG. 16 (A). Therefore, a value very close to the ideal state (6 times)
Is obtained.

In other words, even if the processing is originally slowed down by the function of changing the priority of the clipping plane, it can be considerably prevented.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

For example, in the present invention, the operation method of the clipping process performed by the clipping operation unit is not limited to the above-described operation method, and an operation method using various algorithms can be used.

Further, as the priority storage means in the present invention, not only a register formed by a flip-flop or the like, but also a memory such as an SRAM or a DRAM as long as it can store at least the priority (index data). You may use it.

Further, the three-dimensional simulator device of the present invention can be applied to various things such as a business game machine, a home game device, a flight simulator, a driving simulator used in a driving school, and the like. Further, the present invention can be applied to a large attraction type game device and a simulation device in which a large number of players participate.

In the present invention, the arithmetic processing performed in the virtual three-dimensional space arithmetic means, the image synthesizing means, the clipping processing device and the like may be performed using a dedicated image processing device, or may be performed using a general-purpose microcomputer, DSP, or the like. The processing may be performed using software.

Further, the calculation processing performed by the virtual three-dimensional space calculation means, the image synthesis means, and the like is not limited to those described in the present embodiment.

Further, the three-dimensional simulator apparatus of the present invention includes a configuration in which a pseudo three-dimensional image obtained by image synthesis is displayed on a display called a head mounted display (HMD).

Claims (20)

(57) [Claims] 1. A clipping processing apparatus for performing a clipping process using a plurality of clipping planes on a three-dimensional object represented by a set of a plurality of polygons, wherein the clipping plane used for the clipping processing is designated. Means for storing index data for storing the priority of the clipping plane by storing the index data in the order of performing the clipping process from the highest storage location to the lower storage location of the storage means, Means for setting an initial value of the index data in the priority storage means; means for reading index data of a clipping plane from the priority storage means; and changing the index data read by the reading means to change the priority. Memory Using a priority changing unit that writes back to a column, and a clipping calculation process performed on the polygon to be processed by using the clipping plane specified by the index data sequentially read from the highest storage location of the storage unit by the reading unit. An internal / external determination unit for determining whether a polygon to be processed is located in a surface area, a boundary area, or a non-display area of the clipping plane; and When the polygon is determined to be in the boundary area by the means, the means for calculating the internal dividing point between the polygon and the clipping plane is determined, and the polygon is determined by the interior / external determination means to be in the display outside area. Means for performing an arithmetic process for invalidating the polygon in the case, If the priority changing unit determines that the polygon to be processed is in the non-display area of the clipping plane by the clipping calculation unit, the index data of the clipping plane is stored in the highest storage location of the storage unit. A clipping processing device comprising means for transferring. 2. The clipping plane index data according to claim 1, wherein the priority changing unit determines that the processing target polygon is located outside the display area of the clipping plane by the clipping calculation unit. Is transferred to the highest storage location of the storage means, and the index data stored from the highest storage location to the storage location one level higher than the storage location of the transferred index data is sequentially transferred. A clipping processing device comprising means for decrementing and transferring to a lower storage location. 3. The apparatus according to claim 1, further comprising: means for performing pre-processing on the entire three-dimensional object before performing the clipping processing on the polygons constituting the three-dimensional object; Before setting a trivial clipping zone having a predetermined width formed so as to include the clipping plane, and before determining whether the three-dimensional object is in a display area, a boundary area, or a non-display area of the zone. When the processing determining means and the preprocessing determining means determine that the three-dimensional object is in the display area or the non-display area of the zone, the clipping processing for the polygons constituting the three-dimensional object is omitted. , If it is determined to be in the boundary area for the zone, Means for designating that clipping processing is to be performed on polygons constituting an original object. 4. The apparatus according to claim 2, further comprising: means for performing pre-processing on the entire three-dimensional object before performing the clipping processing on polygons constituting the three-dimensional object; Before setting a trivial clipping zone having a predetermined width formed so as to include the clipping plane, and before determining whether the three-dimensional object is in a display area, a boundary area, or a non-display area of the zone. When the processing determining means and the preprocessing determining means determine that the three-dimensional object is in the display area or the non-display area of the zone, the clipping processing for the polygons constituting the three-dimensional object is omitted. , If it is determined to be in the boundary area for the zone, Means for designating that clipping processing is to be performed on polygons constituting an original object. 5. The polygon according to claim 1, wherein said interior dividing point computing means included in said clipping computing section changes an operation coefficient used for said interior dividing point computation to obtain a polygon to be processed. A clipping processing device comprising means for performing a perspective projection conversion process. 6. The polygon according to claim 2, wherein said internal dividing point calculating means included in said clipping calculating means changes a calculation coefficient used for said internal dividing point calculation to obtain a polygon to be processed. A clipping processing device comprising means for performing a perspective projection conversion process. 7. A polygon as a processing target according to claim 3, wherein said internally dividing point calculating means included in said clipping calculating means changes an arithmetic coefficient used for said internally dividing point calculation. A clipping processing device comprising means for performing a perspective projection conversion process. 8. The polygon according to claim 4, wherein said internal dividing point calculating means included in said clipping calculating means changes a calculation coefficient used for said internal dividing point calculation to obtain a polygon to be processed. A clipping processing device comprising means for performing a perspective projection conversion process. 9. The apparatus according to claim 1, further comprising means for setting an initial value set by said initial value setting means for each three-dimensional object according to a display state of a three-dimensional object formed by polygons. Clipping processing device. 10. The apparatus according to claim 2, further comprising means for setting an initial value set by said initial value setting means for each three-dimensional object according to a display state of a three-dimensional object formed by polygons. Clipping processing device. 11. The apparatus according to claim 3, further comprising means for setting an initial value set by said initial value setting means for each three-dimensional object according to a display state of a three-dimensional object constituted by polygons. Clipping processing device. 12. The apparatus according to claim 4, further comprising means for setting an initial value set by said initial value setting means for each three-dimensional object according to a display state of a three-dimensional object formed by polygons. Clipping processing device. 13. The apparatus according to claim 5, further comprising means for setting an initial value set by said initial value setting means for each three-dimensional object according to a display state of a three-dimensional object formed by polygons. Clipping processing device. 14. The apparatus according to claim 6, further comprising means for setting an initial value set by said initial value setting means for each three-dimensional object according to a display state of a three-dimensional object constituted by polygons. Clipping processing device. 15. The apparatus according to claim 7, further comprising means for setting an initial value set by said initial value setting means for each three-dimensional object according to a display state of a three-dimensional object formed by polygons. Clipping processing device. 16. The apparatus according to claim 8, further comprising means for setting an initial value set by said initial value setting means for each three-dimensional object according to a display state of a three-dimensional object constituted by polygons. Clipping processing device. 17. A three-dimensional simulator including the clipping processing device according to any one of claims 1 to 16, wherein a viewer in a virtual three-dimensional space is used by using a polygon subjected to clipping processing by the clipping processing device. A three-dimensional simulator apparatus comprising at least image synthesizing means for synthesizing a visual field image viewed from the outside. 18. A clipping processing method for performing a clipping process on a three-dimensional object represented by a set of a plurality of polygons using a priority storage unit that stores a priority of a clipping surface used for the clipping process, wherein Setting an initial value of the priority of the clipping plane in the storage unit; and displaying the polygon to be processed using the clipping plane in order from the clipping plane with the highest priority stored in the priority storage unit. Determining whether the polygon is in a boundary area or a non-display area; and, if the determination step determines that the polygon to be processed is in the boundary area, an internal dividing point between the polygon and the clipping plane. Calculate A clipping operation step of performing an operation for invalidating the polygon when it is determined that the polygon is in the non-display area; and a polygon to be processed by the clipping operation step is displayed in the non-display area of the clipping plane. If it is determined that there is, the step of changing the priority of the priority storage means so that the priority of the clipping plane is the highest. 19. The method according to claim 18, further comprising: before performing the clipping process on the polygons constituting the three-dimensional object, performing a pre-process on the entire three-dimensional object. Setting a zone for trivial clipping of a predetermined width formed so as to include a surface, and determining whether the three-dimensional object is in a display area, a boundary area, or a non-display area of the zone; If it is determined in the determination step that the three-dimensional object is in the display area or the non-display area for the zone, clipping processing for polygons constituting the three-dimensional object is omitted, and the boundary area for the zone is If it is determined that there is a Clipping processing method characterized in that with respect to the polygons constituting the-objects and a step of specifying the performing clipping processing. 20. The method according to claim 18, wherein the initial value set in the initial value setting step is set for each three-dimensional object according to a display state of the three-dimensional object constituted by polygons. Clipping treatment method.