Abstract:
Disclosed is a game system comprising a monitor ( 3 ) that outputs the game screen display, a touch panel ( 5 ), and an external memory device ( 20 ) that stores sequence data ( 28 ) which records the operation timing for touch operation of a touch panel ( 5 ). The game system displays an object ( 60 ) that corresponds to the operation timing and an operation reference indicator ( 55 ) that corresponds to the current time in the game and guides the player&#39;s touch operation by reducing the distance between the object ( 60 ) and the operation reference indicator ( 55 ) according to the difference between the operation timing and the current time and by moving the object ( 60 ) such that the object ( 60 ) matches the operation reference indicator ( 55 ) at the operation timing. The game system also changes the distance between the object ( 60 ) and the operation reference indicator ( 55 ) in accordance with predetermined conditions.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a national stage application of PCT/JP2011/055828, filed Mar. 11, 2011, which claims priority to Japanese Patent Application No. 2010-058108, filed Mar. 15, 2010, the disclosures of which are hereby incorporated by reference in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to a game system in which an operation timing of an operating unit disposed in an input device is indicated to a player, a control method of controlling a computer and a storage medium storing a computer program a computer program used thereof. 
     BACKGROUND ART 
     There have been known game systems in which an operation timing of an operating unit disposed in an input device is indicated to a player in tune with a rhythm of music. Of the game systems, there is a game system including an obstructing device that hides a part of an operation indication mark used to indicate an operation timing during the progress of a game (for example, see Patent Literature 1). Besides, another background art related to the invention is disclosed in Patent Literature 2.
     Patent Literature 1: Japanese Patent No. 3031676 and Patent Literature 2: Japanese Patent No. 2922509.   

     SUMMARY OF INVENTION 
     Technical Problem 
     In the game machine disclosed in Patent Literature 1, a timing mark serving as an operation indication mark moves toward a lower end serving as an operation reference mark. And, an obstruction of hiding a part of the operation indication mark is made to change a difficulty level of a game, and thus amusement of a game is improved. However, the operation indication mark merely moves to reduce a distance from the lower end with the lapse of time. For this reason, a development of a game is easily predicted. 
     In this regard, the invention is directed to provide a game system, a control method of controlling a computer and a storage medium storing a computer program used therein, which are capable of changing the distance between the operation indication mark and the operation reference mark according to a predetermined condition. 
     Solution to Problem 
     A game system of the present invention comprises: an input device that includes at least one operating unit; a display device that displays and outputs a game screen; a sequence data storage device that stores sequence data in which operation timing of the operating unit during a game is described; and an operation guide device that guides a player to operate the operating unit by causing an operation indication mark corresponding to the operation timing and an operation reference mark corresponding to a current time in the game to be displayed on the game screen based on the sequence data, generating relative displacement along a predetermined path according to the progress of the game between the operation indication mark and the operation reference mark such that a distance between the operation indication mark and the operation reference mark decreases based on a time difference between an operation timing guided through the operation indication mark and the current time, and the operation indication mark matches with the operation reference mark at the operation timing guided through the operation indication mark, and wherein the operation guide device includes a distance change device that changes a distance between the operation reference mark and the operation indication mark according to a predetermined condition. 
     According to the present invention, the distance between the operation reference mark and the operation indication mark can be changed according to a predetermined condition. For this reason, for example, the distance between the operation reference mark and the operation indication mark can be not only decreased but also increased. Thus, compared to the game development of the conventional game in which the distance between the operation reference mark and the operation indication mark is only decreased, it is difficult to predict the game development. For this reason, compared to the conventional game, the player further focuses his/her attention to change of the operation indication mark or the like. Thus, amusement of a game can be improved. 
     In an aspect of the game system of the present invention, the distance change device may use a predetermined operation as the predetermined condition, and change the distance between the operation reference mark and the operation indication mark in response to the predetermined operation. In this case, since the distance between the operation reference mark and the operation indication mark is changed in response to the player&#39;s operation, it is possible to make the player easily recognize relevance between a change in the distance between the operation reference mark and the operation indication mark and a predetermined operation. 
     The change in the distance between the operation reference mark and the operation indication mark may be made in an arbitrary manner. For example, in an aspect of the game system of the present invention, the distance change device may change the distance between the operation reference mark and the operation indication mark by changing a direction of the relative displacement along the predetermined path between the operation indication mark and the operation reference mark up to a predetermined position in a reverse direction. Further, in this aspect, the operation guide device may further include a direction change device that generates the relative displacement in an original direction from the predetermined position such that the operation indication mark matches with the operation reference mark at operation timing described in the sequence data. In this case, a direction of the relative displacement may be changed to a reverse direction, that is, a direction in which the distance between the operation indication mark and the operation reference mark increases, up to the predetermined position. Further, it is possible to return the relative displacement to the original direction in which the distance between the operation reference mark and the operation indication mark decreases from the predetermined position again according to the lapse of time, and the operation indication mark matches with the operation reference mark at the operation timing so that the operation timing can be guided. Thus, a new game development can be provided. 
     Further, any displacement may be generated as the relative displacement along a predetermined path between the operation indication mark and the operation reference mark. For example, in an aspect of the game system of the present invention, the operation guide device may move the operation indication mark toward the operation reference mark as the relative displacement along the predetermined path. 
     In an aspect of the game system of the present invention, the game system may further comprise an evaluating device that evaluates an operation in at least one operating unit based on timing of the operation on the operating unit and the operation timing designated in the sequence data. In this case, the timing of the operation on the operating unit can be evaluated based on the operation timing described in the sequence data. Thus, amusement of the game can be further improved. Furthermore, in this aspect, the distance change device may use an evaluation result of the evaluating device as the predetermined condition, and change the distance between the operation reference mark and the operation indication mark according to the evaluation result. In this case, the evaluation result on the player&#39;s operation can be reflected in a change in the distance between the operation reference mark and the operation indication mark. 
     In an aspect of the game system of the present invention, the input device may include a plurality of operating units, the operation timing may be described in the sequence data so as to be associated with information designating any one of the plurality of operating units, and the operation guide device may generate the relative displacement along the predetermined path in an aspect in which an operating unit corresponding to each operation timing can be discriminated. In this case, the distance between the operation reference mark and the operation indication mark can be changed in an aspect in which a correspondence relation with each operating unit can be discriminated. 
     Any aspect may be used as the aspect in which an operating unit corresponding to each operation timing can be discriminated. For example, in an aspect of the game system of the invention, the operation guide device may generate the relative displacement along the predetermined path in a aspect in which an operating unit corresponding to each operation timing can be discriminated by displaying a plurality of paths each of which is discriminated for each operating unit and corresponds to each operating unit on the game screen as the predetermined path. 
     Further, any device may be used as the input device. For example, in an aspect of the game system of the present invention, a touch panel arranged on the display device so as to cover the game screen may be used as the input device. 
     In an aspect of the game system of the present invention, the game system may further comprise: an audio output device that reproduces and outputs a game sound; a music data storage device that stores music data for reproducing music; and a music reproducing device that causes the audio output device to reproduce the music based on the music data, and wherein the operation timing of the operating unit during reproduction of the music is described in the sequence data. In this case, it is possible to achieve a music game in which displacement occurs such that the operation indication mark matches with the operation reference mark at an operation timing corresponding to a rhythm of the music, and the distance between the operation reference mark and the operation indication mark can be changed according to a predetermined condition. 
     A control method of controlling a computer of the present invention is a control method of controlling a computer which is incorporated in a game system comprising: an input device that includes at least one operating unit; a display device that displays and outputs a game screen; a sequence data storage device that stores sequence data in which operation timing of the operating unit during a game is described, wherein the control method of controlling the computer comprises the steps: an operation guide step that guides a player to operate the operating unit by causing an operation indication mark corresponding to the operation timing and an operation reference mark corresponding to a current time in the game to be displayed on the game screen based on the sequence data, generating relative displacement along a predetermined path according to the progress of the game between the operation indication mark and the operation reference mark such that a distance between the operation indication mark and the operation reference mark decreases based on a time difference between an operation timing guided through the operation indication mark and the current time, and the operation indication mark matches with the operation reference mark at the operation timing guided through the operation indication mark; and a distance change step that changes a distance between the operation reference mark and the operation indication mark according to a predetermined condition in the operation guide step. 
     A storage medium storing a computer program for a game system of the present invention is a storage medium storing a computer program for a game system comprising: an input device that includes at least one operating unit; a display device that displays and outputs a game screen; a sequence data storage device that stores sequence data in which operation timing of the operating unit during a game is described, wherein the computer program is configured to cause a computer which is incorporated in the game system to serve as; an operation guide device that guides a player to operate the operating unit by causing an operation indication mark corresponding to the operation timing and an operation reference mark corresponding to a current time in the game to be displayed on the game screen based on the sequence data, generating relative displacement along a predetermined path according to the progress of the game between the operation indication mark and the operation reference mark such that a distance between the operation indication mark and the operation reference mark decreases based on a time difference between an operation timing guided through the operation indication mark and the current time, and the operation indication mark matches with the operation reference mark at the operation timing guided through the operation indication mark, and the computer program is configured to further cause the operation guide device to serve as; a distance change device that changes a distance between the operation reference mark and the operation indication mark according to a predetermined condition. It is possible to actualize the game system of the present invention by executing the control method of controlling a computer of the present invention or the computer program for a game system. 
     Advantageous Effects of Invention 
     As described above, according to the present invention, it is possible to change the distance between the operation indication mark and the operation reference mark according to a predetermined condition. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram illustrating an example of a game machine to which a game system according to an embodiment of the invention is applied. 
         FIG. 2  is a functional block diagram of a game machine. 
         FIG. 3  is a diagram schematically illustrating a game screen. 
         FIG. 4  is a diagram schematically illustrating a game screen when an appropriate touch operation is executed. 
         FIG. 5  is a diagram schematically illustrating a game screen after a predetermined time elapses from a state of  FIG. 4 . 
         FIG. 6  is a diagram illustrating an example of content of sequence data. 
         FIG. 7  is a diagram illustrating an example of a flowchart of a sequence process routine. 
         FIG. 8  is a diagram illustrating an example of a flowchart of an object assignment process routine. 
         FIG. 9  is a diagram illustrating an example of a flowchart of an operation evaluation routine. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of a game system according to the invention will be described.  FIG. 1  is a diagram illustrating a game machine for business use to which a game system according to an embodiment of the invention is applied. As illustrated in  FIG. 1 , a game machine  1  includes a casing  2 , and a monitor  3  serving as a display device arranged, obliquely toward a player P side, on the top surface of the casing  2 . A transparent touch panel  5  serving as an input device is superimposed on the surface of the monitor  3 . The touch panel  5  is a known input device that outputs a signal corresponding to a contact position when the player P contacts the touch panel  5  with his/her finger or the like. In addition, the game machine  1  includes various kinds of input devices and output devices disposed in a typical game machine for business use such as a button used to make a selection or a decision, a power switch, a volume operation switch, and a power lamp, which are not illustrated in  FIG. 1 . 
       FIG. 2  is a functional block diagram of the game machine  1 . As illustrated in  FIG. 2 , a control unit  10  serving as a computer is disposed in the casing  2 . The control unit  10  includes a game control unit  11  serving as a control host, a display control unit  12  that operates according to an output from the game control unit  11 , and an audio output control unit  13 . The game control unit  11  is configured as a unit in which a microprocessor is combined with various kinds of peripheral devices such as an internal storage device (for example, a read only memory (ROM) or a random access memory (RAM)) necessary for an operation of the microprocessor. The display control unit  12  causes a predetermined image to be displayed on the monitor  3  by rendering an image corresponding to image data provided from the game control unit  11  in a frame buffer and then outputting a video signal corresponding to the rendered image to the monitor  3 . The audio output control unit  13  causes a predetermined sound (including music or the like) to be reproduced from a speaker  14  serving as an audio output device by generating an audio reproduction signal corresponding to audio reproduction data provided from the game control unit  11  and then outputting the generated audio reproduction signal to the speaker  14  connected to the control unit  10 . 
     An external storage device  20  is connected to the game control unit  11 . As the external storage device  20 , there is used a storage medium in which data remains stored even when power is not supplied such as an optical storage medium including a digital versatile disc-read only memory (DVD-ROM) and a compact disc-read only memory (CD-ROM), a non-volatile semiconductor memory device including an electrically erasable programmable read-only memory (EEPROM). 
     A game program  21  and game data  22  are stored in the external storage device  20 . The game program  21  is a computer program necessary for the game machine  1  to execute a music game according to a predetermined procedure, and includes a sequence control module  23  and an evaluating module  24  in order to achieve a function according to the invention. When the game machine  1  is activated, the game control unit  11  executes various kinds of initial settings necessary to operate the game machine  1  by executing an operation program stored in an internal storage device thereof, and then sets an environment in which a music game is executed according to the game program  21  by reading the game program  21  from the external storage device  20  and then executing the game program  21 . When the sequence control module  23  of the game program  21  is executed by the game control unit  11 , a sequence processing unit  15  is generated in the game control unit  11 . Further, when the evaluating module  24  of the game program  21  is executed by the game control unit  11 , an operation evaluating unit  16  is generated in the game control unit  11 . The sequence processing unit  15  and the operation evaluating unit  16  are logical devices actualized by a combination of computer hardware and a computer program. The sequence processing unit  15  executes a music game process which includes instructing the player to make an operation in tune with reproduction of music selected by the player, generating a sound effect in response to the player&#39;s operation, or the like. The operation evaluating unit  16  executes a process which includes evaluating the player&#39;s operation and then controlling a game based on an evaluation result, or the like. In addition, the game program  21  includes various kinds of program modules necessary to execute a music game in addition to the modules  23  and  24 , and logical devices corresponding to the modules are generated in the game control unit  11  although not illustrated. 
     The game data  22  includes various pieces of data to be referred to when a music game is executed according to the game program  21 . For example, the game data  22  includes music data  25 , sound effect data  26 , and image data  27 . The music data  25  is data necessary to cause music which is a target of a game to be reproduced and output from the speaker  14 .  FIG. 2  illustrates a single kind of music data  25 , but the player can actually select a piece of music to be played from among a plurality of pieces of music. In the game data  22 , one or more pieces of music data  25  are recorded in association with information identifying each piece of music. The sound effect data  26  is data in which each of one or more types of sound effects to be output from the speaker  14  in response to the player&#39;s operation is recorded in associated with a unique code for each sound effect. Sounds of musical instruments and various kinds of sounds are included as the sound effect. Pieces of sound effect data which are equal in number to a predetermined octave number and have different musical pitches according to a sound type are prepared. The image data  27  is data for causing a background image, various kinds of objects or icons, and the like in a game screen to be displayed on the monitor  3 . 
     The game data  22  further includes sequence data  28 . The sequence data  28  is data used to define an operation timing to be indicated to the player. At least one sequence data  28  is prepared for a single music data. The details of the sequence data  28  will be described later. 
     Next, an outline of a music game executed by the game machine  1  will be described. The game machine  1  is configured as a music game machine of a type that evaluates an operation timing thereof or the like when the player executes an operation in tune with music. A game screen is displayed on the monitor  3  while the music game is being executed through the game machine  1 .  FIG. 3  is a diagram schematically illustrating the game screen. As illustrated in  FIG. 3 , a plurality of lanes SR serving as a predetermined path, which extend in a vertical direction, are displayed on the game screen  50 . The plurality of lanes SR are visually separated by means such as three separator lines SS of a first lane SR 1 , a second lane SR 2 , and a third lane SR 3  arranged in order from the left. An operation reference mark  55  is displayed on lower end portions of the three lanes SR so as to cross the lanes SR 1 , SR 2 , and SR 3 . Further, an upper reference line UL is displayed on the upper side of the three lanes SR so as to cross the lanes SR 1 , SR 2 , and SR 3  at the position apart from the upper end portions of the lanes SR 1 , SR 2 , and SR 3  by a predetermined distance. During execution of a music game, that is, during the progress of reproduction of music, objects  60  serving as an operation indication mark are displayed on the lanes SR 1 , SR 2 , and SR 3  according to the sequence data  28 . 
     The object  60  appears from the upper end portion of each of the lanes SR 1 , SR 2 , and SR 3  at an appropriate timing in a piece of music, passes through the upper reference line UL, and moves toward the operation reference mark  55  at the lower side according to the progress of a piece of music as indicated by an arrow A in  FIG. 3 . The player is required to perform a touch operation of touching the operation reference mark  55  of the lane SR on which the object  60  is displayed in tune with an arrival of the object  60  at the operation reference mark  55 . Here, when the player performs the touch operation, a time difference between a time at which the object  60  matches with the operation reference mark and a time at which the player performs the touch operation is detected. The smaller the time difference is, the higher the player&#39;s operation is evaluated. Further, a sound effect corresponding to each object  60  is reproduced from the speaker  14  in response to the touch operation. In the example of  FIG. 3 , the objects  60  are displayed on the upper side of the first lane SR 1  and the middle portion of the third lane SR 3 , respectively, and are moving toward the operation reference mark  55 . It is preferable that the player touch the operation reference mark  55  positioned on the third lane SR 3 , for example, in tune with an arrival of the object  60  at the operation reference mark  55  of the third lane SR 3 . In this embodiment, three operating units are formed by combination of the operation reference mark  55  and the lanes SR 1 , SR 2 , and SR 3  displayed on the monitor  3 , and the touch panel  5  superimposed thereon. Further, in the following, the operation reference mark  55  or each of the lanes SR 1 , SR 2 , and SR 3  may be used as a term representing the operating unit. 
     Further, when an appropriate touch operation is executed in tune with an arrival of each object  60  at the operation reference mark  55 , the object  60  moves back up to a predetermined position SL present in a direction in which the object  60  has moved along the lane SR on which the appropriate touch operation is executed, that is, in an upper direction.  FIG. 4  is a diagram schematically illustrating a game screen when the appropriate touch operation is executed.  FIG. 4  illustrates an example in which an appropriate operation is performed on the third lane SR 3 , that is, the example in which the touch operation is performed on the operation reference mark positioned on the third lane SR 3  in tune with an arrival of the object  60  at the operation reference mark  55 . As illustrated in  FIG. 4 , in third lane SR 3 , the object  60  on which the appropriate touch operation has been executed moves back toward the upstream side in the moving direction in response to the touch operation. An arrow B in  FIG. 4  represents a direction in which the object  60  on which the appropriate touch operation has been executed moves back. And, after the object  60  moves back to the predetermined position SL indicated by a dashed line above the upper reference line UL, the object  60  moves downward, that is, toward the operation reference mark  55  again along the third lane SR 3  in order to indicate new operation timing. In addition, in  FIGS. 4 and 5 , the predetermined position SL is indicated by the dashed line, but the predetermined position SL is not displayed on the actual game screen. For this reason, the upper reference line UL is provided as a reference to the predetermined position SL. 
       FIG. 5  is a diagram schematically illustrating a game screen after a predetermined time elapses from the state of  FIG. 4 . As illustrated in  FIG. 5 , the object  60  that has moved up to a part above the upper reference line UL in the third lane SR 3  moves toward the operation reference mark  55  again right up to the operation reference mark  55 . The player is required to perform an appropriate operation again in tune with an arrival of the object  60  at the operation reference mark  55 . Then, when the appropriate operation is executed on the object  60 , the object  60  moves upward again. In other words, as long as the appropriate touch operation is executed, the object  60  repeats upward retreat movement and downward movement. 
     Meanwhile, the object  60  on which the appropriate touch operation has not been executed passes through the operation reference mark  55  and then disappears from the game screen  50 . Then, a new object  60  appears from the upper end portion, and moves toward the operation reference mark  55 . The example of  FIG. 5  illustrates a state directly before the object  60  of the second lane SR 2  which is the object  60  on which the appropriate touch operation has not been executed disappears from the game screen  50 . Further,  FIG. 5  illustrates the example in which the appropriate operation has not been executed on the object  60  displayed on the first lane SR 1  in  FIG. 4 . In this case, in the first lane SR 1 , a new object  60  appears from the upper end portion, and moves toward the operation reference mark  55  at the lower side as illustrated in  FIG. 5 . As described above, a game is played such that the player executes an appropriate operation on the object  60  moving downward from the upper side at an appropriate timing, and when an appropriate operation has been executed, an object returned to the upper side is repeatedly used as the object  60  indicating new operation timing. 
     Next, the details of the sequence data  28  will be described with reference to  FIG. 6 . The sequence data  28  includes a condition definition portion  28   a  and an operation sequence portion  28   b  as illustrated in  FIG. 6 . In the condition definition portion  28   a , there is described information designating an execution condition of a game that differs according to a piece of music, such as information designating the tempo, a beat, a track of music, a sound effect to be generated when the touch operation is performed on the object  60 , or the like. In addition, in  FIG. 6 , the condition definition portion  28   a  is provided in the head portion of the sequence data  28 , but the condition definition portion  28   a  may be added to an appropriate intermediate position of the operation sequence portion  28   b . Thus, processes including a change of the tempo of music, an assignment of a sound effect, or the like can be achieved. 
     Meanwhile, in the operation sequence portion  28   b , operation timing of lanes SR are described in association with information designating any one of lanes SR 1 , SR 2 , and SR 3 . As partially illustrated in  FIG. 6 , the operation sequence portion  28   b  is configured as a set of a plurality of records in which a timing (operation timing) to perform an operation in music is associated with information designating each of lanes SR 1 , SR 2 , and SR 3  (corresponding to the operating unit). The operation timing is described such that a bar number in music, beats, and a value representing a time in a beat are separated by a comma. A time in a beat represents an elapsed time from the head of one beat, and is represented by the number of units, from the head of the beat, obtained by equally dividing the time length of one beat into n unit times. For example, when n is 100 and ¼ has elapsed from the head of a second beat in a second beat of a first bar of a piece of music is designated as an operation timing or a display start timing, “01,2,025” is described. 
     For the lanes SR 1 , SR 2 , and SR 3 , “lane  1 ” is described when the first lane SR 1  is designated, “lane 2 ” is described when the second lane SR 2  is designated, and “lane 3 ” is described when the third lane SR 3  is designated. In the example of  FIG. 6 , an operation timing and an operating unit are designated such that the touch operation is performed on the operation reference mark  55  on the third lane SR 3  at a starting point in time (000) of a fourth beat of a first bar, the touch operation is performed on the operation reference mark  55  on the second lane SR 2  at a timing in which “010” has elapsed from the starting point in time of the fourth beat of the first bar, and the touch operation is performed on the operation reference mark  55  on the third lane SR 3  at a timing in which “016” has elapsed from the starting point in time of the fourth beat of the first bar. The sequence processing unit  15  of the game control unit  11  controls a display of each of the lanes SR 1 , SR 2 , and SR 3  such that the operation reference mark  55  matches with the object  60  at an operation timing designated by the sequence data  28 . 
     Next, a process of the game control unit  11  when the game machine  1  executes a music game will be described. The game control unit  11  reads the game program  21  and performs initial setting necessary to execute a music game, and then is on standby for a game start instruction from the player. For example, the game start instruction includes an operation specifying data used in a game such as selection of a piece of music to be played in a game or a difficulty level. A procedure receiving the instruction may be the same as in a known game. 
     When a game start is instructed, the game control unit  11  causes reproduction of the music to be started through the speaker  14  by reading the music data  25  corresponding to music selected by the player and outputting the read music data  25  to the audio output control unit  13 . Through this operation, the control unit  10  functions as a music reproducing device. Further, the game control unit  11  causes the game screen  50  to be displayed on the monitor  3  by reading the sequence data  28  corresponding to the player&#39;s selection in synchronization with reproduction of the music, generating image data necessary for the game screen  50  with reference to the image data  27 , and outputting the generated image data to the display control unit  12 . Further, as processes necessary to display the game screen  50  or the like during execution of the music game, the game control unit  11  repeatedly executes a sequence process routine illustrated in  FIG. 7 , an object assignment process routine illustrated in  FIG. 8 , and an operation evaluation routine illustrated in  FIG. 9  in a predetermined cycle. In addition, the sequence processing unit  15  handles the routines of  FIGS. 7 and 8 , and the operation evaluating unit  16  handles the operation evaluation routine of  FIG. 9 . 
       FIG. 7  illustrates an example of a flowchart of the sequence process routine executed by the sequence processing unit  15 . When the routine of  FIG. 7  starts, in step S 1 , the sequence processing unit  15  of the game control unit  11  first acquires a current time in the music. For example, clocking starts, by an internal clock of the game control unit  11 , from a reproduction start point in time of the music, and the current time is acquired based on a value of the internal clock. Subsequently, in step S 2 , the sequence processing unit  15  acquires data of operation timing present in a time length corresponding to a display range of the game screen  50  from the sequence data  28 . For example, the display range is set to a time range of about two bars of the music from the current time to the future. 
     Next, in step S 3 , the sequence processing unit  15  executes an assignment of the object  60  corresponding to each acquired operation timing. For example, this assignment is achieved by executing the routine of  FIG. 8 .  FIG. 8  illustrates an example of a flowchart of an assignment process routine executed by the sequence processing unit  15 . The sequence processing unit  15  executes the routine of  FIG. 8  on each of acquired operation timings. When the routine of  FIG. 8  is started, in step S 11 , the sequence processing unit  15  determines whether or not the object  60  has been already assigned to an operation timing of a target. When the determination result is positive, that is, when it is determined that the object  60  has been already assigned to an operation timing of a target, the subsequent process is skipped, and the current routine ends. In addition, an example of determining the presence or absence of the assignment will be described in detail in subsequent step S 13 . 
     When the determination result in step S 11  is negative, the sequence processing unit  15  proceeds to step S 12 . In step S 12 , the lane SR on which an operation timing of a target is to be displayed is determined based on the description of the sequence data  28 , and it is determined whether or not a retreating object  60  is present in the determined lane SR within a predetermined time period. The retreating object  60  represents the object  60  that moves back up to a part above the upper reference line UL in the third lane SR 3  in the example of  FIG. 4 . The details of processing of the retreating object  60  will be described with reference to the routine of  FIG. 9 . Further, when an operation timing of a target is assigned to the retreating object  60 , as a predetermined time period, there is set a time period in which trouble such as the high speed which is inappropriate for indicating operation timing or the like does not occur. For example, at the stage in which the assignment process is being executed, in the cases such as a case that the retreating object  60  is positioned above the upper reference line UL, a case that the retreating object  60  is positioned within a predetermined range from the upper reference line UL, or the like, the predetermined time period may be set to correspond to the position of the retreating object  60 . Alternatively, a condition of a predetermined time period may be omitted. When the determination result in step S 12  is negative, that is, when it is determined that no retreating object  60  is present in the lane SR of the target within a predetermined time period, the sequence processing unit  15  proceeds to step S 13 . On the other hand, when the determination result is positive, the sequence processing unit  15  proceeds to step S 14 . 
     In step S 13 , the sequence processing unit  15  assigns a new object  60  to an operation timing of a target, and then ends the current routine. For example, this assignment is achieved such that the sequence processing unit  15  adds object information used for distinction from the retreating object  60  to the operation timing. For example, information such as “A” may be added as the object information. Further, based on the presence or absence of the object information, in step S 11 , the sequence processing unit  15  can determine whether or not the object  60  has been already assigned to an operation timing of a target. 
     Meanwhile, in step S 14 , the sequence processing unit  15  assigns the retreating object  60  to the operation timing of the target, and ends the current routine. For example, this assignment can be achieved by adding the object information to the operation timing as described above. Further, in this case, for example, “S” may be used as object information corresponding to the retreating object  60 . 
     In addition, the assignment process of the object  60  is not limited to the above-described example. For example, when the retreating object  60  is present in the lane SR corresponding to the operation timing of the target, the assignment can be also achieved by correcting an appearance position at which a next object  60  appears to the predetermined position SL above the upper reference line UL up to which the retreating object  60  moves upward. In this case, the retreating object  60  disappears at the predetermined position SL to which the retreating object  60  has moved back along the moving direction, a new object  60  indicating a next operation timing appears at the disappearance position, and the new object  60  moves toward the operation reference mark  55  to arrive at the appropriate timing. Thus, a rendering effect by which a single object  60  repeatedly moves up and down can be made. 
     Referring back to the routine of  FIG. 7 , subsequently, in step S 4 , the sequence processing unit  15  calculates coordinates of each object  60  which has been subjected to the assignment in step S 3  in the game screen  50 . For example, this calculation is performed as follows. Among the lanes SR 1 , SR 2 , and SR 3 , the lane on which the object  60  is to be arranged is determined based on a designation of any one of the lanes SR 1 , SR 2 , and SR 3  associated with an operation timing corresponding to each object  60 , that is, a designation of any one of “lane 1 ” to “lane 3 ” in the example of  FIG. 6 . Next, the position of each object  60  from the operation reference mark  55  in the time axis direction (that is, the moving direction of the object  60 ) is determined based on a time difference between each operation timing and a current time. Through this operation, it is possible to acquire coordinates of each object  60  necessary to arrange each object  60  on the designated one of the lanes SR 1 , SR 2 , and SR 3  along the time axis from the operation reference mark  55 . Further, at this time, coordinates of the retreating object  60  are calculated by considering the predetermined position SL above the upper reference line UL to which the retreating object  60  moves up as the appearance position. 
     Next, in step S 5 , the sequence processing unit  15  generates image data necessary to render the game screen  50  based on the coordinates of each object  60  calculated in step S 4 . Specifically, the image data that causes each object  60  to be arranged at the calculated coordinates is generated. Subsequently, in step S 6 , the sequence processing unit  15  outputs the image data to the display control unit  12 . As a result, the game screen  50  is displayed on the monitor  3 . When the process of step S 6  ends, the sequence processing unit  15  ends the current sequence process routine. By repeatedly executing the above process, the objects  60  are displayed to move along the lanes SR 1 , SR 2 , and SR 3  such that the object  60  arrives at the operation reference mark  55  at operation timing described in the sequence data  28 . Further, when the appropriate operation is executed on the operation reference mark  55  at an appropriate timing, the retreating object  60  that moves back up to the predetermined position SL above the upper reference line UL and then moves toward the operation reference mark  55  again is displayed to move toward the operation reference mark  55  to match with the operation reference mark  55  at a new operation timing as the object  60  indicating the new operation timing. 
     Next, the operation evaluation routine of  FIG. 9  will be described. When the operation evaluation routine of  FIG. 9  starts, in step S 21 , the operation evaluating unit  16  first determines the presence or absence of the touch operation on the operation reference mark  55  with reference to an output signal of the touch panel  5 . At this time, when the position other than the operation reference mark  55  is touched, it is determined that there is no touch operation. When it is determined that there is no touch operation, the operation evaluating unit  16  ends the current routine. On the other hand, when it is determined that there is the touch operation, the operation evaluating unit  16  proceeds to step S 22 . In step S 22 , the operation evaluating unit  16  determines the position of the operation reference mark  55  at which the touch operation is performed based on the position signal output from the touch panel  5 , and then further determines whether or not the determined position of the operation reference mark  55  is an appropriate position. At this time, the operation evaluating unit  16  first specifies a lane SR corresponding to a nearest operation timing described in the sequence data  28 , that is, a lane SR corresponding to an operation timing which is closest in time in the sequence data  28 . And, the operation evaluating unit  16  employs the position of the operation reference mark  55  on the lane SR corresponding to the specified operation timing as an appropriate position. Thus, the operation evaluating unit  16  compares the position of the operation reference mark  55  on the lane SR corresponding to the operation timing which is closest in time in the sequence data  28  with the position of the operation reference mark  55  at which the touch operation has been performed, and determines whether or not the position of the touch operation is appropriate. When the determination result in step S 22  is positive, the operation evaluating unit  16  proceeds to step S 23 . On the other hand, when the determination result is negative, the operation evaluating unit  16  skips the subsequent process, and ends the current routine. 
     In step S 23 , the operation evaluating unit  16  determines timing (a time in music) at which the touch operation is performed. Subsequently, in step S 24 , the operation evaluating unit  16  specifies a nearest operation timing described in the sequence data  28 , that is, an operation timing which is closest in time in the sequence data  28 , and acquires a time difference between the operation timing and a time at which the touch operation has been made. Next, in step S 25 , the operation evaluating unit  16  determines whether or not the player&#39;s operation is appropriate by determining whether or not the time difference is within an evaluation range. A predetermined time range before and after an operation timing of a comparison target is set as the evaluation range. For example, a plurality of steps of levels is set centering on the operation timing, and a time range in which the levels are set is used as the evaluation range. When it is determined in step S 25  that the time difference is outside the evaluation range, the operation evaluating unit  16  ends the current routine. On the other hand, when it is determined that the time difference is within the evaluation range, the operation evaluating unit  16  proceeds to step S 26 . 
     In step S 26 , the operation evaluating unit  16  starts a display of a backward movement that the object  60  arriving at the operation reference mark  55  moves back toward the predetermined position SL above the upper reference line UL. As a result, the object  60  starts to move toward the predetermined position SL above the upper reference line UL in an upper direction which is a direction reverse to the moving direction. This object  60  serves as the retreating object  60  in the routines of  FIGS. 8 and 9 . In step S 27 , the operation evaluating unit  16  decides an evaluation on the player&#39;s touch operation based on the time difference acquired in step S 24 . For example, this evaluation is achieved by determining whether or not a timing of the touch operation belongs to any one of a plurality of levels set in the time range. A plurality of levels are set such that the time range is divided in units of predetermined time periods, and the touch operation that belongs to a division close to an operation timing of each division is highly evaluated. Thereafter, the operation evaluating unit  16  proceeds to step S 28 , and controls an output to the display control unit  12  such that the evaluation result is displayed on the game screen  50 . When the process of step S 28  is completed, the operation evaluating unit  16  ends the current routine. 
     As described above, according to the game machine of this embodiment, the object  60  starts to move back in a direction reverse to the moving direction in response to the appropriate touch operation. And, the object  60  that has moved back starts to move toward the operation reference mark  55  from the predetermined position SL again in order to indicate a new operation timing. In other words, the distance between the object  60  and the operation reference mark  55  can be not only decreased but also increased. Further, since the operation timing is guided using the object  60  that repeatedly moves forward or backward with respect to the operation reference mark  55 , the player needs to take the course of the object  60  after the touch operation into account. For this reason, compared to when the object  60  just moves toward the operation reference mark  55  to reduce the distance, a new game element can be added. Thus, amusement of a game can be improved. 
     In the above embodiment, the external storage device  20  of the game machine  1  serves as a music data storage device and a sequence data storage device. Further, the control unit  10  serves as an operation guide device and a direction change device by causing the sequence processing unit  15  to execute the routines of  FIGS. 7 and 8 . Furthermore, the control unit  10  serves as a distance change device and an evaluating device by causing the operation evaluating unit  16  to execute the routine of  FIG. 9 . 
     The invention is not limited to the above embodiment and can be embodied in appropriate embodiments. In the above embodiment, an evaluation result of the player&#39;s touch operation is used as the predetermined condition. And, when the touch operation is appropriate, backward movement and forward movement with respect to the operation reference mark are repeatedly executed. In this case, an evaluation may be executed based on the number of times that the object  60  repeats backward movement and forward movement with respect to the operation reference mark. For example, an evaluation may be executed such that a bonus score is given each time the number of repetition times reaches 10 times, 20 times, or the like. 
     Further, in the above embodiment, an evaluation result of the player&#39;s touch operation is used as the predetermined condition, but the invention is not limited to this example. For example, the presence or absence of the player&#39;s touch operation may be used as the predetermined condition instead of the evaluation result. Further, various kinds of conditions may be used as the predetermined condition according to a game progress condition such as an option for the progress of a game or the development of a game. 
     In the above embodiment, an intermediate state of the backward movement of the object  60  that retreats upward from the operation reference mark  55  to the predetermined position SL above the upper reference line UL is also displayed, but the intermediate movement state may not be displayed. In other words, the intermediate state of the backward movement of the object  60  that started to move backward is not displayed, and instead, a display may be performed such that the object  60  instantly moves to the predetermined position SL of a target position above the upper reference line UL. 
     In the above embodiment, the object  60  serving as the operation indication mark moves toward the operation reference mark  55 , but the invention is not limited to this embodiment. For example, the operation reference mark may move toward the operation indication mark, or both the operation reference mark and the operation indication mark may be displaced. 
     Further, in the above embodiment, it is possible to discriminate an operating unit corresponding to each operation timing by using a lane discriminated for each operating unit, but the present invention is not limited to this embodiment. For example, each operating unit may be discriminated using an operation indication mark that differs in color, shape, or the like according to each operating unit. Further, in the above embodiment, a plurality of operating units is disposed, but the present invention is not limited to this embodiment. The present invention can be applied even when a single operating unit is disposed. 
     In the above embodiment, the touch panel is used as the input device, but the input device is not limited to this embodiment. For example, as long as an operating unit is disposed like a controller in which a plurality of push buttons serving as an operating unit are provided, input devices having various configurations may be used. 
     In the above embodiments, the game machine  1  is configured as a music game machine in which music is reproduced, and an operation indication mark moves toward an operation reference mark based on a played time of the music. However, the present invention is not limited to this embodiment. The game machine  1  can execute various kinds of games as long as operation timing is indicated through a video. Furthermore, the game system of the invention may be actualized in appropriate embodiments such as a game machine for business use installed in commercial facilities, a stationary game machine for home use, a portable game machine, or a game system implemented using a network. 
     REFERENCE SIGNS LIST 
     
         
           1 : Game machine 
           3 : Monitor (display device) 
           5 : Touch panel (input device and operating unit) 
           14 : Speaker (audio output device) 
           10 : Control unit (computer, operation guide device, distance change device, direction change device, evaluating device, and music reproducing device) 
           20 : External storage device (music data storage device and sequence data storage device) 
           21 : Game program 
           22 : Game data 
           25 : Music data 
           28 : Sequence data 
           50 : Game screen 
           55 : Operation reference mark 
           60 : Object (operation indication mark) 
         SR 1 : First lane (predetermined path) 
         SR 2 : Second lane (predetermined path) 
         SR 3 : Third lane (predetermined path) 
         SL: Predetermined position 
         UL: Upper reference line