JP2736879B2 - 3D graphic data reduction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reducing three-dimensional graphic data, and more particularly to a method for reducing polygon data representing a three-dimensional graphic into groups and reducing unnecessary polygons for each group. Things.

[0002]

2. Description of the Related Art In general, in three-dimensional graphic processing by an arithmetic processing unit, a polygon data format is used in which a three-dimensional surface shape is approximated by combining a large number of polygons called polygons. This polygon data is composed of vertex coordinates and its connection information. By increasing the size and number of polygons, the accuracy of expressing three-dimensional figures can be increased. The amount of data also increases.

Therefore, when transmitting a three-dimensional figure represented by polygon data, the communication time increases as the number of polygons increases. In the case of displaying a moving image of a three-dimensional figure, real-time display becomes difficult because the processing capability of the arithmetic processing unit is limited. For these reasons, it is required to reduce the polygon data in accordance with the accuracy required for expressing the three-dimensional figure and the allowable calculation processing time.

When the polygon data is to be reduced, a normal vector of the polygon to be reduced and a polygon adjacent to the polygon, that is, a vector perpendicular to the polygon surface is calculated, and the angle difference between the two normal vectors is calculated. ,
When the angle difference is equal to or smaller than a predetermined threshold, a method of integrating both polygons into one polygon is considered. In addition, there has been proposed a method of dividing the data into groups according to the amount of reduction, setting a threshold value for each group, and improving the reduction rate.

[0005]

Therefore, in such a conventional three-dimensional graphic data reduction method, the reduction processing is performed based on a predetermined threshold value, and it is difficult to predict the reduction result. Until the required amount of reduction is obtained, it is necessary to set a threshold value for each processing unit such as a group and verify the reduction result by trial and error, and it takes time and effort to obtain the desired result. was there. The present invention has been made to solve such a problem, and an object of the present invention is to provide a three-dimensional graphic data reduction method capable of reducing polygon data at a desired reduction rate according to expression accuracy in a shorter time. The purpose is.

[0006]

In order to achieve such an object, a method for reducing three-dimensional graphic data according to the present invention comprises:
A plurality of reduction processing computers that perform reduction processing of polygon data belonging to a predetermined group in which a predetermined reduction rate is set;
A total processing computer connected to each reduction processing computer via a network and controlling each reduction processing computer is provided,
The general processing computer distributes each polygon data to each reduction processing computer for each group, instructs reduction processing based on the reduction rate set for each group, and collects reduction results from each reduction processing computer Thus, a three-dimensional figure is reconstructed. The integrated processing computer checks the execution environment of the reduction processing in each reduction processing computer, and causes the plurality of reduction processing computers capable of executing the reduction processing to execute the reduction processing in parallel.
Therefore, a predetermined polygon data reduction process is performed by each reduction processing computer based on a predetermined reduction rate for each group. Also, predetermined polygon data reduction processing is performed in parallel by each reduction processing computer.

In addition, a shared storage device that can be shared by the general processing computer and each reduction processing computer is provided, and the reduction results from each reduction processing computer are totaled by the shared storage device. Therefore, the reduction results from each reduction processing computer are totaled in the shared storage device. Further, each reduction processing computer rearranges the sorted polygon data based on a predetermined reduction reference value, and performs reduction processing on polygons corresponding to the reduction rate according to the order. Therefore, the polygon data allocated to each reduction processing computer is rearranged based on the predetermined reduction reference value, and the reduction processing is performed on the polygons corresponding to the reduction rate according to the order. Further, each reduction processing computer saves the rearrangement result of the polygon data, and uses the rearrangement result stored at the time of the next reduction processing. Therefore, the result of rearranging the polygon data is stored and reused in the next reduction processing.

[0008]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram of a three-dimensional graphic data reduction apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 114 denotes a general processing computer that performs general processing of polygon data reduction, and 113 denotes a general processing computer 114. A connection terminal for connecting to the network 115, 123 is a reduction processing computer for performing reduction processing, 124 is a connection terminal for connecting the reduction processing computer 123 to the network 115, and 125 is a general processing computer 114 and a reduction processing computer 1
23 is a shared storage device that can be shared and used.

In the general processing computer 114, reference numeral 102 denotes a CRT for displaying various information; 103, an external storage device for storing a large number of polygon data constituting three-dimensional graphic data as a file; Keyboard 105, a comprehensive processing program 106
And a general processing memory 101 having an internal table 112 required for processing. Reference numeral 101 denotes a CPU which executes a program 106 in the memory 105 in accordance with an instruction input from the keyboard 104 to perform a general processing of polygon data reduction. .

In the general processing program 106, reference numeral 107 denotes a reduction processing computer 123 on the network 115 and an internal table 11 in the general processing computer 114.
2, a computer registration routine for reading polygon data from the external storage device 103, a group distribution routine 109 for transferring data for each group to the reduction processing computer 123, and 1.
10 is a reduction result totaling routine for totalizing the reduction results of the reduction processing computer 123, and 111 is the external storage device 1 for storing the reduction results.
This is a reduction result output routine to be written to the file 03.

In the reduction processing computer 123, 1
Reference numeral 16 denotes a CPU for performing the reduction processing, and 117 denotes a reduction processing memory having a reduction processing program 118. In the reduction processing program 118, 119 is the general processing computer 1
A data receiving routine 120 for receiving polygon data from 14, a data sorting routine 120 for rearranging the polygon data according to the angle difference between the normals of the polygons,
Reference numeral 121 denotes a data reduction routine for performing a reduction process by integrating polygon data according to a reduction rate. Reference numeral 122 denotes a reduction result output routine for returning a reduction result to the general processing computer 114.

Next, the operation of the present invention will be described with reference to FIG. In the general processing computer 114, the keyboard 104
In response to the instruction input from the CPU 101, the CPU 101 executes the general processing program 106. First, a computer registration routine 107 as shown in FIG. 2 is executed. CPU10
1 reads a list of computers connected to the network 115 from the external storage device 103 (step 201),
The execution environment of each computer is checked to determine whether the reduction program can be executed in each computer in the computer list (step 202).

If it is feasible (step 20)
3: YES), the computer is registered in the internal table 112 (step 204), all the computers listed in the computer list are repeatedly examined (step 205), and the process is terminated. Next, the CPU 101
In order to read the three-dimensional graphic data from the external storage device 103, a data reading routine 108 as shown in FIG. 3 is executed.

First, a predetermined three-dimensional graphic data file stored in the external storage device 103 is opened in a readable state (step 301), and vertex data of polygon data stored in the file is read (step 301). Step 302). Fig. 4 shows a 3D graphic data file.
Where 401 is header information indicating a data format such as the number of vertices and the number of polygons, 402 is vertex coordinate information of all polygons, and 403 is a polygon constituting each group and the polygons This is polygon information having a plurality of polygon groups 404 including vertex coordinates.

In this case, the vertex coordinate information 402 includes “vert
The polygon information 403 is described in a range surrounded by “polygon” and “end”, as well as in a range surrounded by “ex” and “end”. In particular, vertex coordinate information 4
02 is a vertex number individually assigned to the extension point,
And coordinate values on the X, Y, and Z axes.

Each polygon data in the polygon information 403 is described for each polygon group 404. The group 404 has a group name (having "g" as a header) and a polygon to which the group belongs. And a vertex number group constituting the polygon. Therefore, step 3
02, vertex coordinate information 402 starting with “vertex” is read into the internal table 112, and then polygon information 403 is read.
, A polygon group 404 is read for each group.

First, a group name starting with "g" of the polygon group 404 is read (step 303), and then polygon data consisting of a plurality of vertex numbers is read and written into the internal table 112 (step 304). This is repeated for all polygon groups 404 (step 305: NO).

When the reading of all the polygon groups 404 is completed (step 305: YES), the three-dimensional graphic data file in the external storage device 103 is closed (step 306). In this way, the data reading routine 108 stores the polygon data from the predetermined three-dimensional graphic data file in the external storage device 103 into the internal table 112 for each group.

Next, the CPU 101 converts the read polygon data into predetermined reduction processing computers 12 for each group.
In order to perform the distribution processing by distributing the group to No. 3, a group distribution routine 109 as shown in FIG. 5 is executed. First, in the computer registration routine 107 described above (see FIG. 2), a computer list of the reduction processing computer 123 registered in the internal table 112 and capable of executing the reduction processing is read (step 501).

Next, an arbitrary polygon data group is assigned to the reduction processing computer 123 capable of executing the reduction processing.
Assignment (step 502), each polygon group 4
04 and the reduction processing target data including the reduction rate are transmitted to each reduction processing computer 123 or the shared storage device 125 (step 503). FIG. 6 is a configuration diagram showing the internal table 112 necessary for the group assignment routine 108, in which reference numeral 601 denotes a reduction processing computer list;
Is a group information list read from the three-dimensional graphic data file.

The reduction processing computer list 601 manages the status of the available reduction processing computers 123. If an arbitrary polygon group 404 has already been allocated, the processing is "in process", and the group information is still allocated. If not, the status is "unused". If the reduction process has already been completed, the status is "output". In the group information list 602, the distribution status of each group is managed. When the distribution is completed, the status is "end", and when the distribution is not completed, the status is "unprocessed".

Based on the reduction processing computer list 601 and the group information list 602, each polygon group 404 is allocated to an arbitrary deletion processing computer 123 (step 504), and according to the end of the distribution of all group data. (Step 504: YES),
The process ends. In this way, the internal table 112
The polygon data read into the data is distributed to an arbitrary deletion processing computer 123 for each group, and the reduction processing computer 123 performs a polygon data reduction process described later.

The reduction rate of each polygon group 404 may be set and input from the keyboard 104 with respect to each polygon group 404 read by the data reading routine 108 described above. May be stored in the external storage device 103 as a file, read out to the internal table 112 as necessary, and transmitted to each reduction processing computer 123.

Next, the CPU 101 executes a reduction result totaling routine 110 as shown in FIG. 7 in order to collect the reduction processing results from each reduction processing computer 123. First, the reduction processing computer list 60 described above (see FIG. 6).
1 (step 701), each reduction processing computer 1
It is determined whether the reduction process in step 23 has been completed (step 7).
02) When all the reduction processes have been completed (step 702: YES), the reduction results are linked.

First, the reduction result is read from each reduction processing computer 123 or the shared storage device 125 (step 703), and each reduction result is connected to one (step 70).
4). This is repeatedly executed for the reduction result of each polygon group 404 (step 705: NO), and upon completion of the connection of all the reduction results (step 705: YE)
S), the process ends.

Subsequently, the CPU 101 stores the reduction results collected in this way as a file in the external storage device 103.
, A reduction result output routine 111 as shown in FIG. 9 is executed. First, a predetermined file for reduction result output is opened in the external storage device 103 (step 801), and based on the reduction results collected and connected, the reduced and unnecessary vertices are stored in the vertex information in the internal table 112. 402 is reduced (step 802), and the reduced vertex information 402 is written to the external storage device 103 (step 803).

Next, after writing the polygon information 403 comprising each polygon group 404 to the external storage device 103 based on the reduction result (step 804), the internal table 112 is cleared (step 805). Is closed (step 806). In this way, polygon data is allocated to each reduction processing computer 123 connected via the network 115 in units of groups, and predetermined polygon data reduction processing is executed in parallel. Since the data is output as a file after the reduced data, the time required for the reduction process can be significantly reduced.

Next, with reference to FIG. 1, the polygon data reduction processing in each reduction processing computer will be described.
The CPU 116 of the reduction processing computer 123 executes a reduction program 118 for predetermined polygon data according to an instruction from the general processing computer 114. First, C
The PU 116 executes a data input routine 119 as shown in FIG. 9 to read the polygon data to be processed.

First, after confirming the connection with the general processing computer 114 (step 901), the vertex information 402 is read directly from the general processing computer 114 via the network 115 or from the shared storage device 125 (step 90).
2). Next, the polygon group 4 allocated in the group allocation processing 109 of the comprehensive processing program 106
04 and read the group information (step 9
03), reading the polygon data constituting the group (step 904), and reading the reduction rate corresponding to the polygon group 404 (step 905).

Subsequently, the CPU 116 sorts the relationship between any two polygons based on the angle difference calculated from the inner product of the normal vectors of adjacent polygons. Execute First, two adjacent polygons are arbitrarily selected, and these polygon data are grouped as a set.
7 is stored in the array secured (step 1001).

Next, a normal vector of each set of polygons stored in the array is obtained (step 1002), and an inner product of these two normal vectors is obtained (step 1003). For example, each of the normal vectors of the two polygons to be any _{set, A = (x a, y} a, z a) B = (x b, y b, z b) and then, these normal vectors A, B When but the angle difference and theta, normal vectors a, inner product of B is, | a || B | cosθ = x a · x b + y a · y b + z a
· A z _b.

Subsequently, the angle difference between the two normal vectors is calculated from the inner product (step 1004). That is, from the equation above inner product, cos [theta] _{is, cosθ = (x a · x} b + y a · y b + z a · z b) /
(| A || B |) However ^{_{| A | = (x a 2}} + y a 2 + z a 2) 1/2 | B | = (x b 2 + y b 2 + z b 2) 1/2 , and the this cosθ The angle difference θ is determined. The polygon sets are sorted (rearranged) in ascending order of the angle difference thus obtained (step 1005), and the sorted result is stored in the shared storage device 125 (step 100).
6).

FIG. 11 is an explanatory diagram showing the operation of the data sorting routine.
4 ", 1106 is an array indicating a set of polygons, 1107 is an angle difference between normal vectors of the polygons forming the set, and 1105 is a pointer array indicating the array 1106. Therefore,
Instead of actually sorting array 1106, array 1
An array 1105 of pointers pointing to each element of
By operating based on the angle difference 1107, each set is sorted by the angle difference.

Next, the CPU 116 executes a data reduction routine 121 as shown in FIG. 12 to reduce polygon data based on the reduction rate. First, the reduction rate read by the aforementioned data input routine 119 is obtained (step 1201), and the aforementioned data sort routine 1 is obtained.
The polygons corresponding to the reduction rate are selected in ascending order of the angle difference sorted by step 20 (step 1202), and the two polygons forming the selected set of polygons are integrated as one polygon (step 1203).

FIG. 13 is an explanatory diagram showing the operation of the data reduction routine 121, and particularly shows a case where the reduction rate is set to 50%. First, based on the pointer array 1105,
A set of 50% from the smaller angle difference 1107, in this case “Polygon 3-4” and “Polygon 2
The set of "3" is selected. Subsequently, “polygon 3-4” and “polygon 2-3” constituting these sets are each integrated as one polygon, and as a result, a polygon 1301 composed of “polygon 1” and a polygon “polygon 2,
A polygon 1302 composed of "3, 4" is generated.

After the polygon data has been reduced in this way, the CPU 116 outputs a result of the reduction, as shown in FIG.
A reduction result output routine 122 shown in FIG. First, after confirming the connection with the integrated processing computer 114 (step 1401), it is directly sent to the integrated processing computer 114 via the network 115 or the shared storage device 125.
, The group name is output (step 1402), and the polygon data after reduction is output (step 14).
03).

As described above, based on the reduction rate set for each group, the two pairs of polygons are selected by the reduction rate in ascending order of the angle difference between the normal vectors of the two polygons forming the pair, and the selected group is formed. Since the polygon data is reduced by integrating one polygon into one polygon, the polygons are grouped in advance based on the expression accuracy required for each part of the three-dimensional figure. Compared with the case where uniform reduction processing is performed on all data, it is possible to obtain a desired reduction rate as a whole while maintaining the expression accuracy required for each part.

Further, since the intermediate result of the reduction processing is stored in the shared storage device 125 connected to the network 115, retransmission of the same data is avoided. further,
Since the result sorted by the data sorting routine 120 of the reduction processing computer 123 is stored in the shared storage device 125, it is possible to omit the sorting processing in the reduction processing from the next time.

[0039]

As described above, according to the present invention, a plurality of reduction processing computers for performing a reduction processing of polygon data belonging to a predetermined group having a predetermined reduction rate, and each reduction processing computer is connected to the network via a network. A total processing computer is connected to control each reduction processing computer. The total processing computer distributes each polygon data to each reduction processing computer for each group, and sets the reduction rate set for each group. , A reduction process is instructed, a reduction result from each reduction processing computer is collected, and a three-dimensional figure is reconstructed. Therefore, predetermined polygon data reduction processing is performed in a distributed manner in each reduction processing computer based on a predetermined reduction rate for each group, and reduction processing is performed based on a conventional predetermined threshold value. In comparison, it is easier to predict the reduction result, and it is not necessary to set a threshold value for each processing unit such as a group and to verify the reduction result until the required reduction amount is obtained. It is possible to reduce the time and labor required until it is obtained.

Further, the execution environment of the reduction processing in each reduction processing computer is checked by the integrated processing computer, and the reduction processing is executed in parallel by a plurality of reduction processing computers capable of executing the reduction processing. Compared with the case where the reduction processing is sequentially performed by two computers, the time required for the reduction processing can be significantly reduced. Further, a shared storage device that can be shared by the integrated processing computer and each reduction processing computer is provided, and the reduction results from each reduction processing computer are totaled by the shared storage device, so that retransmission of the same data is avoided.

Further, each of the reduction processing computers rearranges the sorted polygon data based on a predetermined reduction reference value, and performs the reduction processing on the polygons corresponding to the reduction rate in accordance with the order. It is possible to more accurately reduce polygons according to a preset reduction rate. In addition, each reduction processing computer saves the rearrangement result for polygon data and uses the rearrangement result saved at the next reduction processing. The replacement can be omitted, and the time required for the reduction process can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a three-dimensional graphic data reduction device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a computer registration routine.

FIG. 3 is a flowchart showing a data reading routine.

FIG. 4 is an explanatory diagram showing a configuration of a three-dimensional graphic data file.

FIG. 5 is a flowchart illustrating a group assignment routine.

FIG. 6 is an explanatory diagram showing a computer list and a group information list.

FIG. 7 is a flowchart showing a reduction result totaling routine.

FIG. 8 is a flowchart illustrating a reduction result output routine.

FIG. 9 is a flowchart showing a data input routine.

FIG. 10 is a flowchart showing a data sort routine.

FIG. 11 is an explanatory diagram showing an operation of a data sort routine.

FIG. 12 is a flowchart illustrating a data reduction routine.

FIG. 13 is an explanatory diagram showing an operation of a data reduction routine.

FIG. 14 is a flowchart illustrating a reduction result output routine.

[Explanation of symbols]

101: CPU, 102: CRT, 103: external storage device, 104: keyboard, 105: memory for general processing,
106: Comprehensive processing program, 107: Computer registration routine, 108: Data reading routine, 109: Group allocation routine, 110: Reduction result totaling routine, 111: Reduction result output routine, 112: Internal table, 113: Connection terminal, 114 ... Comprehensive processing computer, 1
15 network, 116 CPU, 117 memory for reduction processing, 120 data sort routine, 121
Data reduction routine, 122... Reduction result output routine,
123: reduction processing computer, 124: connection terminal.

Claims (5)

(57) [Claims] In a three-dimensional graphic data reduction method for reducing unnecessary polygons among polygon data expressing a three-dimensional graphic by combining a large number of polygons, the polygon data belongs to a predetermined group in which a predetermined reduction rate is set. A plurality of reduction processing computers for performing polygon data reduction processing, and a total processing computer connected to each reduction processing computer via a network and controlling each reduction processing computer are provided. Distribute to each reduction processing computer for each group, instruct reduction processing based on the reduction rate set for each group, collect reduction results from each reduction processing computer, and reconstruct a three-dimensional figure A method for reducing three-dimensional graphic data, characterized in that: 2. The three-dimensional graphic data reduction method according to claim 1, wherein the general processing computer checks an execution environment of the reduction processing in each reduction processing computer.
A method for reducing three-dimensional graphic data, wherein a plurality of reduction processing computers capable of executing the reduction processing execute the reduction processing in parallel. 3. The three-dimensional graphic data reduction method according to claim 1, further comprising: a shared storage device that can be shared by the general processing computer and each of the reduction processing computers; and a reduction result from each of the reduction processing computers is stored in the shared storage device. A method for reducing three-dimensional graphic data, characterized in that the totalization is performed. 4. The three-dimensional graphic data reduction method according to claim 1, wherein each reduction processing computer rearranges the sorted polygon data based on a predetermined reduction reference value, and reduces the sorted polygon data by the reduction rate according to the order. A three-dimensional figure data reduction method, wherein a reduction process is performed on the polygons. 5. The three-dimensional graphic data reduction method according to claim 4, wherein each reduction processing computer stores a result of the rearrangement with respect to polygon data,
A method for reducing three-dimensional graphic data, wherein a rearrangement result stored at the next reduction processing is used.