JP4535299B2 - GAME DEVICE, DATA PROCESSING METHOD, AND RECORDING MEDIUM - Google Patents

Description

  The present invention relates to a video game apparatus. In particular, the present invention relates to a game device capable of performing more realistic image expression with a game device installed in an amusement center or home, and an image processing device used therefor.

  With the advance of computer technology, video game devices using computer graphics technology have been widely used. This type of video game device is widely accepted by users. Many different game devices have been devised, and various game software corresponding to them has been supplied.

  In order to allow the user to enjoy the video game more, it is desired that the image be displayed on the screen with a more realistic expression. For example, in a vehicle race such as a car race, it is desirable that the movement of the vehicle or the background is naturally expressed.

  One element for expressing this natural movement is control of data reading when data in a wide game space is read from a recording medium such as a CD-ROM into a memory in the game apparatus and displayed.

  Even in the same game space, when a character moves slowly like RPG (role playing game) or moves to another place in an instant, data processing is temporarily stopped and data is read. Therefore, it is very easy to control the reading of such data.

  However, in the case of a car racing game or the like, for example, in the case of a car racing game or the like, the continuous movement of the character has a huge amount of background data that must be read along with the movement of the vehicle. It becomes very troublesome. For example, once image processing is stopped and data is read as in RPG, the game is stopped and cannot be established as a car racing game. On the other hand, reading all background data of a wide game space from a CD-ROM or the like into a memory is impossible as a practical problem from the viewpoint of the memory capacity and the time required for reading.

  Therefore, in the case of a game that displays a screen in which a character moves at a high speed like a conventional car racing game, the background data is divided into areas along the traveling path, and the background data of the necessary area is pre-read. While processing the image.

  However, a game that can be dealt with by this prefetching method is a car racing game in which a vehicle as a moving object runs on a predetermined course (running path). In this case, when the vehicle passes a certain point in the course, the background data of the next area is stored in the free memory area. In recent car racing games or car games, a game characterized by a player being able to run a vehicle in any direction within the game space has begun to appear. In the case of such a game, it is left to the player's operation to travel in a plurality of branched traveling paths, or on grasslands that are not originally traveling paths. In other words, it is very difficult for the device to simply determine a block of a traveling path that will run in the near future from the current vehicle speed and vehicle position and to prefetch background data.

  Therefore, in the present invention, in a game where a player can move an object such as a vehicle in an arbitrary direction in the game space, the background data necessary for image processing is reliably obtained in each case while using a relatively simple technique. It is an object of the present invention to provide a smooth, stable and high-quality game image by prefetching.

  In order to achieve this object, the present invention provides a game in which background data necessary for a game in which a moving body moving in a virtual three-dimensional space is displayed together with a background is read from storage means into a work memory prior to image processing. In the apparatus, pre-reading means for pre-reading the background data from the storage means using a reference line set at a predetermined distance from the limit line in the visual field direction of the display is provided.

  According to another aspect of the present invention, in the game device, the storage unit stores the background data by dividing the background data into a plurality of areas in advance, and the prefetch unit stores the reference line in any of the areas. And a reading means for reading the background data of the area determined to be applied to the reference line by the determining means into the work memory.

  According to still another aspect of the present invention, in the game device, the plurality of areas are stored in the storage means by dividing the content of background data into types of backgrounds and divided into substantially equal areas, respectively, and While the work memory has a plurality of memory blocks set to the same storage capacity, the reading means has n or more (n is a positive integer value) background data of each area according to the data amount. Means for storing in the memory block;

  In still another embodiment, the reading means determines whether the work memory block is an empty area, and when the determination results in determining that the work memory block is an empty area, Means for sequentially storing the data in at least one memory block.

  According to another aspect, in the game device, whether the moving body exists in each area corresponding to a memory block in which the background data of the work memory is stored, or whether there is an area within the field of view. Count means for detecting whether or not the memory block has a free area, and when the read means determines that there is no free space in the memory block, the counter means counts each of the memory blocks. Deciding means for deciding a memory block as a storage destination in which the background data is stored.

  According to still another aspect, in the game apparatus, the reading unit includes a determining unit that determines the plurality of consecutive memory blocks when the background data to be stored requires a plurality of memory blocks.

  In still another embodiment, the determining means is a means for comparing the count values for the plurality of consecutive memory blocks to determine the plurality of consecutive memory blocks exhibiting the highest value or the lowest value.

  Further, according to another aspect of the present invention, in the game device described above, the determining means calculates an average value of the count values for the plurality of consecutive memory blocks, and the calculated value is the highest value or the lowest value. The means for determining the plurality of consecutive memory blocks exhibiting Still another embodiment is a vehicle in which the moving body moves in the virtual three-dimensional space in the game device.

  Another invention for achieving the object is a game apparatus in which background data necessary for a game for displaying a moving body moving in a virtual three-dimensional space together with a background is read from a storage means into a work memory prior to image processing. In the data processing method, the background data is pre-read from the recording medium using a reference line set at a position a predetermined distance away from the limit line in the visual field direction of the display.

  The present invention is further characterized in that it is an information recording medium on which the background data and a program for executing each means are recorded.

  As described above, according to the present invention, in a game in which a player can move an object such as a vehicle in an arbitrary direction in the game space, background data as much as necessary for image processing is obtained in a relatively simple manner. Each time, it is possible to provide a smooth, stable, high-quality game image by prefetching each time.

1 is an overall perspective view of a game device according to an embodiment of the present invention. It is a block diagram which shows the electrical schematic structure of this game device. It is the figure which divided the example of the topography (background) created in a game space. It is a schematic diagram which shows an example which divided the topographic map into areas. It is a figure which illustrates typically a part of memory block set to the main memory as a work memory. It is a figure explaining the positional relationship specific of the reading start line (reference line) and area concerning prefetching. It is a flowchart which shows the outline | summary of the prefetch control process performed by CPU. It is a figure explaining an example of the data storage to the memory block accompanying prefetch. It is a figure explaining another example of the data storage to the memory block accompanying prefetch.

  Next, a game device according to an embodiment of the present invention will be described with reference to FIGS.

  The game apparatus according to this embodiment is a car racing game in which a vehicle as an object is moved in a virtual three-dimensional space (game space). In particular, the traveling path of the vehicle is branched and reaches a destination. However, there are many directions, and it is difficult to specify which route to select, or a car game that can run in any direction in places where the route is not clearly defined, such as grasslands and villages. provide.

  Hereinafter, this game apparatus will be described. FIG. 1 shows an overview of the game apparatus according to this embodiment, and FIG. 2 shows an electrical hardware block diagram thereof.

  As shown in FIG. 1, the game device is configured by connecting a game device body 1, a controller 2, and a subunit 3 to each other.

  The game apparatus body 1 is a control apparatus body that controls the progress of the game. The game apparatus main body 1 can be connected to a plurality of controllers 2 via a connector C. The game apparatus main body 1 includes a CD-ROM drive 11 so that a recording medium (storage means) such as a CD-ROM can be detachably mounted.

  The controller 2 has a configuration as an operation unit operated by a player, and includes an operation button group 21, a cross key 22, an analog direction key 23, an R trigger switch 24, and the like, and a connection cord 4 having a connector P. The game apparatus main body 1 can be connected. These operation units constitute a handle, an accelerator, a brake, a shift lever, and the like necessary for moving the vehicle as a moving object in the three-dimensional virtual space. The player appropriately operates these operation units while watching the monitor screen during the game. As a result, the operation information is transmitted to a later-described CPU of the game apparatus body 1, and the vehicle can be driven in an arbitrary direction in the game space under the control of the CPU.

  In addition, the controller 2 includes a backup memory 3 that is detachable.

  The game apparatus body 1 has a configuration similar to a computer apparatus, and includes a CPU block 30, a video block 31, a sound block 32, a communication device 33, and the like as shown in FIG.

  The CPU block 30 includes a bus aviator 300, a CPU 301, a main memory 302, a ROM 303 and a CD-ROM drive 11. The bus aviator 300 is configured to control transmission / reception of data by allocating a bus occupation time to devices connected to each other via a bus. The CPU 301 is configured to be accessible to the backup memory 3 via the main memory 302, ROM 303, CD-ROM drive 11, video block 31 and sound block 32, and controller 2.

  The CPU 301 can perform various processes and controls necessary for executing the game, transfer image data to the graphic memory 311, and transfer sound data to the sound memory 321. The ROM 303 is a storage area for the initial program loader. The ROM 303 is an element constituting a recording medium, and a program necessary for the processing of the CPU 301 is recorded in advance. In addition, a CD-ROM or the like may be used as this recording medium.

  The CD-ROM drive 11 uses a CD-ROM as a recording medium for data supplied from the outside. The CD-ROM stores a main game program, various necessary data, and background data (texture data or polygon data), and these data are read into the main memory 302 as necessary. Various other recording media may be used instead of this CD-ROM. The program and background data may be transferred to the main memory via the communication device 33. With this setting, data can be transferred from a fixed disk of a remote server.

  The video block 31 includes a VDP (Video Display Processor) 310, a graphic memory 311, and a video encoder 312. With these configurations, the video block 31 performs generation of polygon image data (vehicle as an object), drawing of a background image (mapping of texture data), synthesis of polygon image data on the background image, clipping processing, and the like. The video encoder 312 is configured to be able to convert the image data generated by the VDP 310 into a predetermined television signal such as the NTSC system or the PAL system and output it to a main monitor 35 (such as a cathode ray tube of a television receiver) connected to the outside. Yes.

  The sound block 32 includes a sound processor 320, a sound memory 321, and a D / A converter 322. With these configurations, the sound block 32 is configured to be able to output sound signals by performing speech synthesis based on waveform data. The D / A converter 322 is configured to convert the audio data generated by the sound processor 320 into an analog signal and output the analog signal to a speaker 34 (a speaker of a television receiver or a speaker of an audio device) connected to the outside. .

  The communication device 33 is, for example, a modem or a terminal adapter. The communication device 33 is configured to be connectable to the game apparatus body 1 and can function as an adapter for connecting the game apparatus body 1 and an external line. The communication device 33 can receive data transmitted from a game supply server such as an Internet server connected to the public line network, and supply the data to the bus of the CPU block 30. The public line network may be a subscriber line, a dedicated line, or wired radio.

  Next, the operation of this embodiment will be described focusing on reading background data from the CD-ROM into the main memory 302. This reading is executed by the prefetching method according to the present invention under the control of the CPU 301.

  First, a description will be given from the relationship between the terrain map as background data set for performing the prefetching and the memory blocks assigned to the predetermined areas of the main memory 302 and set to the same storage capacity.

  FIG. 3 shows an example of a terrain map depicted in a virtual three-dimensional space that can be used in the car racing game of this game apparatus. This figure shows the xz plane of the world coordinate system, and the thick black line on this map represents the main travel path R. The running road R is characterized by a large number of branch roads as compared with a car racing game that circulates a normal fixed route. In addition, the road R travels in a great many types and numbers of fields such as urban areas, villages, and grasslands, and is able to travel outside the road R and travel in any direction. Yes.

  Now, a plurality of areas are assumed by dividing a terrain map including a travel route so as to have almost the same area for each type of field. Thereby, areas AR1, AR2, AR3,... Divided by thin lines in FIG. Of these plural areas, as an example, 16 adjacent areas AR1, AR2,..., AR16 are represented as a topographic map (background data) as shown in FIG. For example, the area AR1 is determined as a grassy field, and the area AR2 is determined as a village field. Considering that the amount of data (background data amount) is different because the objects to be arranged differ depending on the type of field, the area indicates the number of blocks of the storage area required when writing to the main memory. Is one block in the memory, two blocks in the memory if the area is a village or town, and three blocks in the memory if the area is a city.

  FIG. 5 shows an example of this data writing. From the top of the figure, the terrain data for the grassland area is stored using 1 block, the terrain data for the village area is stored using 2 blocks in succession, and the terrain data for the urban area is stored using 3 blocks continuously. The Each block MB has the same storage capacity. In this block MB, a count value area of the software counter CT processed by the CPU 301 is set, and the count value is written. This counter CT periodically determines whether there is a vehicle in each area AR corresponding to each block MB in the main memory, or whether there is a background area in the field of view of the camera. The count value of the counter CT of the block MB storing the terrain data of the area that is not present or does not exist in the field of view is incremented for each such determination. For this reason, the count value of the counter CT of the block MB corresponding to the area AR with less traveling of the vehicle becomes higher. Therefore, by checking this count value, it can be seen how frequently the vehicle travels in the corresponding area AR. Even if there are a plurality of blocks MB corresponding to one area AR, the count values are the same between the blocks.

  An area for prefetching is searched for the terrain data divided in this way, and this search method is illustrated in FIG. Now, it is assumed that the vehicle VL is traveling in the village area of the area AR6. In this vehicle VL, a field of view with a predetermined viewing angle θ along the traveling direction is set. A visual field limit line LN1 serving as a clipping position at the time of display is set at a predetermined distance in front of the visual field. Further, in this field of view, a read start line LN2 that constitutes a part of the prefetch function of the present invention is set at a predetermined distance in front of the field limit line LN1.

  This reading start line LN2 is a detection body that precedes in order to determine an area where the pre-reading of terrain data starts. When this line LN2 represents each area by its circumscribed circle, it identifies which circumscribed circle (area) the line LN2 in the field of view is (or enters) and has the identified circumscribed circle Is used as a prefetch target area. In the case of FIG. 6, since the reading start line LN2 is applied to both the circumscribed circle of the city area AR10 and the village area AR11 next to it, it can be determined that the pre-reading areas at the present time are both AR10 and AR11.

  Based on this pre-reading technique, an example of processing of terrain data (background data) reading executed by the CPU 301 will be described with reference to FIG. This process is executed by a timer interruption method at regular intervals, for example.

  First, the CPU 301 reads the player's operation information, and specifies the current vehicle position and traveling direction on the xz plane of the world coordinate system.

  Next, when the CPU 301 sees the field of view along the traveling direction from the current vehicle position (viewpoint), the reading start range, that is, the reading start area in any new area AR (the background data has not yet been read). Whether or not the start line LN2 has entered is determined by the method using the circumscribed circle of the area described above (step S3). When this determination is NO, the reading start line LN2 has not yet entered the new area AR, and the process is returned to the main routine as it is.

  On the other hand, when the determination in step S3 is YES, that is, when the read start line LN2 enters one or more new areas AR, the memory blocks that are unused in the main memory 302 and that are continuous as many as necessary. It is determined whether or not there is an MB (step S4). However, when the number of memory blocks necessary for storing the background data = 1, “necessary number of consecutive memory blocks” means one memory block. If the determination in step S4 is YES, the background data (terrain data) is read from the new area AR and written to the free memory block.

  On the other hand, when the CPU 301 makes a NO determination in step S4, that is, when there is no necessary number of consecutive unused memory blocks, the CPU 301 uses the used memory blocks MB,. It is determined whether or not there is a required number of memory blocks that continuously store background data of one city area (step S6). When this determination is YES, the count values associated with the memory block MB are compared with each other, and the background data of the new area AR is stored in the memory block having the largest value (step S7). If the count value is large, it can be assumed that the background data of the memory block has been used less frequently and will be used in the future. For this reason, the background data of such a memory block is preferentially updated to new background data.

  On the other hand, when the determination in step S6 is NO, the memory blocks in which the background data is continuously stored across a plurality of types of areas are searched, and these are combined and the required number of blocks is set to 1. More than one set is secured (step S8). Next, for each set of such consecutive memory blocks, the average value of the count values of each set of memory blocks is calculated (step S9). Next, the CPU 301 compares the calculated count values to determine a set of memory blocks having the largest count value, and stores background data of a new area AR in each memory block of the set (step S10). The reason for searching for a set of memory blocks having the largest count value is the same as described above.

  8 and 9 schematically show an example of the above-described prefetch process. In these drawings, a single circle indicates a block in which background data (terrain data) read in the past is stored, and a double circle indicates background data of an area where a vehicle currently exists. Or a block in which background data of an area within the field of view from the area is stored. An asterisk (*) indicates that the block continuously stores background data of one area (connected with a minus sign). Further, the + symbol indicates an unused block.

  The example of FIG. 8 shows how the background data of a new area AR is stored using the unused (empty) memory block MB in the main memory 302 (step of FIG. 7). (See S3-S5). It is assumed that the vehicle has already moved to a new area.

  On the other hand, the example of FIG. 9 shows a state in which a memory block MB having background data stored in the past is updated with new background data. That is, after a new area is detected and past continuous background data is updated with the background data, the vehicle has already moved into the new area. In particular, the example of FIG. 9 illustrates a state where four consecutive memory blocks are required as a destination for securing background data of a new area. For this reason, the average value of the count values is calculated through the processing of steps S3, S4, S6, S8 to S10 in FIG. 6-9 were selected. At this time, the adjacent memory block NO. 10 is treated as an empty block. As described above, the background data (for example, the background data of blocks No. 6 to 10) read after the background data (for example, the background data of blocks No. 1 to 5) read earlier is erased first. This is because the course of the vehicle is not linear, and is often advanced by so-called meandering or zigzag running in which it directly enters an area read in the past from another course.

Since the background data (topography data) are preread, CPU 301 is able to control and command the image processing of a car racing game using this as operation information. In such pre-reading processing, the pre-reading start line is set a predetermined distance away from the visibility limit line and the area where the vehicle travels is reliably detected. Detection, that is, prefetching can be performed. Therefore, it is not necessary to increase the storage capacity of the main memory in the apparatus, and of course, it is not necessary to stop the image processing and read the background data. Therefore, on the screen displayed on the monitor 35 by the image processing using the background data, there is no missing image and the like, and a high quality and stable vehicle traveling screen can be displayed.

  In the above-described embodiment, the prefetch start line for prefetch detection has been described as being linear, but it may be arcuate with respect to the viewpoint. The determination as to whether or not the prefetch start line has entered a new area may be made by comparing the rectangular area itself with the position of the prefetch start line without setting a circumscribed circle in the area.

  Furthermore, the handling of the count value of the counter representing the frequency of use of the background data of the memory block is, after detecting that the vehicle does not exist in the corresponding area at regular time intervals, contrary to the above, the count value is changed from the constant value. You may make it decrement. Further, the count value area may be set in a predetermined area of the main memory in association with each block MB without being set in the block MB.

DESCRIPTION OF SYMBOLS 1 Game apparatus main body 2 Controller 11 CD-ROM driver 30 CPU block 31 Video block 32 Sound block 35 Monitor 301 CPU (also serves as a counter means)
302 Main memory (also serves as work memory)
312 Video encoder 303 ROM

Claims (9)

By reading out the game program stored in the detachably mounted storage means and executing the game program, the game screen based on the virtual three-dimensional space is displayed on the display means, and the player is displayed on the game screen. A game device for executing a game capable of selecting a movement path in an arbitrary direction in accordance with an operation on an operation means performed by
The storage means stores a plurality of terrain data,
The game device includes:
A setting means for setting a plurality of areas that can be selected as a moving path by the moving body in the virtual three-dimensional space, corresponding to the plurality of terrain data;
The viewpoint in the virtual three-dimensional space is set to the position of the moving body, the field of view viewed from the viewpoint is set to the traveling direction of the moving body, and the plurality of areas are set based on operation data input from the operating means. Terrain that develops forward in the traveling direction of the moving body that moves in any of the areas , and that is within a limit line set at a predetermined distance from the viewpoint within the viewing angle of the visual field, Image processing means for displaying on the display means;
In response to the operation of the operating means of the player,
(A) identifying a current position and a traveling direction of the moving body in an area where the moving body exists ;
(B) as viewed from said viewpoint in the field of view angle in setting the reference line at a position on the far only Jo Tokoro distance further than the limit line,
(C) detecting an area that is within the viewing angle and includes the reference line;
(D) Among the areas detected in (c), an area in which the corresponding terrain data is not read into the work memory is specified, and the terrain data of the specified area is read from the storage means and stored in the work memory. Read,
Execution means for executing processing at regular intervals;
With
When the current position and / or traveling direction is changed by the movement of the moving body and one of the areas detected in (c) enters the limit line, the image processing means A game apparatus, wherein the topography corresponding to the area previously read is used to display the topography within the limit line based on the current position on the display means. The game device according to claim 1,
The plurality of terrain data is stored in the storage means according to the type of terrain,
The work memory is set with a plurality of memory blocks having the same storage capacity,
The terrain data read from the storage means is read into one or more memory blocks of the plurality of memory blocks according to the amount of data based on the terrain type of the terrain data. . The game device according to claim 2,
When reading the terrain data of the area specified in (d) into the work memory,
It is determined whether there is one or more memory blocks that are unused in the plurality of memory blocks set in the work memory and that correspond to the amount of topographic data in the specified area, and the one or more memory blocks When it is determined that there is a game device, the terrain data of the specified area is read into the one or more memory blocks. The game device according to claim 3,
A plurality of count units respectively corresponding to the plurality of memory blocks;
Periodically determine whether the moving object exists in the area corresponding to the memory block in which the terrain data is already stored, or whether the area exists within the viewing angle; A counting means for counting a count value in the counting unit corresponding to an area where the moving body does not exist or the area is determined not to exist within the viewing angle;
With
When reading the terrain data of the area specified in (d) into the work memory,
Unused and, if it is determined that one or more memory blocks corresponding to the data amount of topographical data of said specified area is not, on the basis of the count value that is counted to each of the plurality of count unit, the One or more memory blocks in which terrain data is already stored are determined, and the terrain data of the specified area is read into the determined one or more memory blocks. The game device according to claim 4, wherein
One or more memory blocks in which the topography data that is determined based on the count value is already stored, compares the count value counted in the counting section, the highest count value among the count value or A game apparatus characterized in that the lowest count value is determined to be one or more memory blocks corresponding to a counting unit counting. The game device according to claim 4, wherein
Said count one or more memory blocks in which the topography data that is determined is already stored on the basis of the value, to search the memory block stored terrain data is continuously across the areas of the plurality of types, the The retrieved memory blocks are combined to secure one or more sets of one or more memory blocks, and the count value of each set is based on the count value counted by the count unit corresponding to the one or more sets of memory blocks. The average value is calculated, and a set of one or more memory blocks corresponding to the counting unit in which the highest count value or the lowest count value among the calculated count values is counted is determined. apparatus. The game device according to any one of claims 1 to 6,
The game apparatus, wherein the moving body is a vehicle that moves in the virtual three-dimensional space. Having means to read out a detachably mounted game data stored in the storage unit has to display a game screen based on the virtual three-dimensional space on the display means, the player makes to the game screen operation a data processing method executed in a computer device that performs any direction of the movement path of which can be selected game in accordance with an operation performed on the device,
The storage means stores a plurality of terrain data,
In the CPU provided in the computer device,
Setting a plurality of areas that can be selected as a moving path by the moving body in the virtual three-dimensional space in correspondence with the plurality of terrain data;
The viewpoint in the virtual three-dimensional space is set to the position of the moving body, the field of view viewed from the viewpoint is set to the traveling direction of the moving body, and the plurality of areas are set based on operation data input from the operating means. Terrain that develops forward in the traveling direction of the moving body that moves in any of the areas , and that is within a limit line set at a predetermined distance from the viewpoint within the viewing angle of the visual field, Displaying on the display means;
In response to the operation of the operating means of the player,
(A) identifying a current position and a traveling direction of the moving body in an area where the moving body exists ;
(B) as viewed from said viewpoint in the field of view angle in setting the reference line at a position on the far only Jo Tokoro distance further than the limit line,
(C) detecting an area that is within the viewing angle and includes the reference line;
(D) Among the areas detected in (c), an area in which the corresponding terrain data is not read into the work memory is specified, and the terrain data of the specified area is read from the storage means and stored in the work memory. Read,
A step of executing the processing at regular intervals;
From changing the current position and / or the direction by the movement of the front Symbol mobile, when said one of said areas detected in (c) has entered the limit line, is read earlier in the work memory Displaying the topography within the limit line based on the current position on the display means, using the topography data corresponding to the area that has been ,
Data processing method, wherein for the execution. Having means to read out a detachably mounted a plurality of terrain data and programs stored in the recording medium, and displays a game screen based on the virtual three-dimensional space on a display means, game for the game screen In a CPU provided in a computer device that executes a game capable of selecting a movement path in an arbitrary direction in accordance with an operation on an operation means performed by a person ,
A step of pre-Symbol mobile in a virtual three-dimensional space is set a selectable plurality of areas so as to correspond to the plurality of terrain data as a moving path,
The viewpoint in the virtual three-dimensional space is set to the position of the moving body, the field of view viewed from the viewpoint is set to the traveling direction of the moving body, and the plurality of areas are set based on operation data input from the operating means. Terrain that develops forward in the traveling direction of the moving body that moves in any of the areas , and that is within a limit line set at a predetermined distance from the viewpoint within the viewing angle of the visual field, and displaying on said display means,
In response to the operation of the operating means of the player,
(A) identifying a current position and a traveling direction of the moving body in an area where the moving body exists ;
(B) as viewed from said viewpoint in the field of view angle in setting the reference line at a position on the far only Jo Tokoro distance further than the limit line,
(C) detecting an area that is within the viewing angle and includes the reference line;
(D) Among the areas detected in (c), an area in which the corresponding terrain data is not read into the work memory is specified, and the terrain data of the specified area is read from the recording medium and stored in the work memory. Read,
A step of executing the processing at regular intervals ;
From changing the current position and / or the direction by the movement of the front Symbol mobile, when said one of said areas detected in (c) has entered the limit line, is read earlier in the work memory Displaying the topography within the limit line based on the current position on the display means, using the topography data corresponding to the area that has been ,
The computer-readable recording medium which recorded the program which performs this .

Images