JP2006252292A - Program, information storage medium and image generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a program, an information storage medium and an image generation system for performing the flexible control of hidden-surface elimination. <P>SOLUTION: This image generation system is provided with a rank information storage part for storing rank information for setting the rank of the plotting sequence of a plurality of model objects, a Z buffer for storing the Z value of each pixel and a plotting part for successively plotting the plurality of model objects while referring to the Z value of the Z buffer from the model object whose plotting sequence rank is low to the model object whose plotting sequence rank is high in a plotting sequence following the rank information. The plotting part clears the Z value of the Z buffer generated by plotting the model object in the Kth plotting sequence rank, and plots the model object in the Lth plotting sequence rank whose rank is higher than the Kth plotting sequence rank. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a program, an information storage medium, and an image generation system.

  Conventionally, an image generation system (game system) that generates an image that can be viewed from a virtual camera (a given viewpoint) in an object space (virtual three-dimensional space) in which an object such as a character is set is known. It is popular as a place to experience so-called virtual reality. Taking an image generation system that can enjoy a role-playing game (RPG) as an example, a player operates a character (a model object in a broad sense), which is his or her own character, and moves it on a map in the object space. Enjoy the game by playing against enemy characters, interacting with other characters, and visiting various towns.

  In such an image generation system, the hidden surface removal is generally performed by a Z buffer method using a Z buffer.

However, it has been found that, depending on the type of game, when the hidden surface removal is uniformly performed by such a Z-buffer method, a defect image is generated in which characters appear to overlap each other. For example, in a game that follows the conventional two-dimensional game technique and moves the player's character on a single reference line in a battle scene to play against an enemy character, the characters appear to overlap each other. Images may be generated frequently.
JP 2004-73241 A

  The present invention has been made in view of the above problems, and an object thereof is to provide a program, an information storage medium, and an image generation system that enable flexible control of hidden surface removal. is there.

  The present invention is an image generation system that generates an image, and includes a rank information storage unit that stores rank information for setting the rank of a drawing order of a plurality of model objects, and a Z buffer that stores a Z value of each pixel. A drawing in which the plurality of model objects are sequentially drawn from a model object having a low drawing order rank to a model object having a high drawing order rank, with reference to the Z value of the Z buffer, in the drawing order according to the rank information. The drawing unit has a higher rank than the Kth drawing order rank after clearing the Z value of the Z buffer generated by drawing the model object having the Kth drawing order rank. Draw model objects of the Lth drawing order rank (K and L are arbitrary integers satisfying 1 ≦ K <N, 1 <L ≦ N, and K <L). Relating to an image generation system. The present invention also relates to a program that causes a computer to function as each of the above-described units. The present invention also relates to a computer-readable information storage medium that stores (records) a program that causes a computer to function as each unit.

  According to the present invention, based on rank information, a plurality of model objects are drawn from a model object with a low drawing order rank to a model object with a high drawing order rank. Then, after clearing the Z value of the Z buffer generated by drawing the model object having the Kth drawing order rank, the model object having the Lth drawing order rank having a higher rank is drawn. In this way, even if the arrangement position of the model object of the Kth drawing order rank and the model object of the Lth drawing order rank is the same or close, the model of the Lth drawing order rank It becomes possible to generate an image in which the object is seen on the front side. In each model object, an appropriate hidden surface removal process is performed using a Z buffer. Accordingly, it is possible to provide an image generation system or the like that enables flexible control of hidden surface removal.

  Note that clearing the Z value of the Z buffer means, for example, setting the Z value to a value representing infinity (deleting the Z value). For example, in a system in which the Z value decreases with increasing distance from the virtual camera, the Z value in the Z buffer can be cleared by setting Z = 0. In a system in which the Z value increases toward the back as viewed from the virtual camera, the Z value in the Z buffer can be cleared by setting Z = infinity.

  In the image generation system, the program, and the information storage medium according to the present invention, the drawing unit draws a background object before drawing the plurality of model objects, and stores the Z buffer generated by drawing the background object. The Z value is copied to the work buffer, and the Z value of the Z buffer generated by drawing the model object of the Kth drawing order rank is combined with the work buffer. The Z value may be cleared.

  In this way, it is possible to prevent the Z value generated in the Z buffer by drawing the background object from being lost due to the Z buffer clear process.

  In the image generation system, the program, and the information storage medium according to the present invention, the drawing unit copies the Z value generated in the work buffer to the Z buffer after the drawing of all the plurality of model objects is completed, Based on the Z value copied to the Z buffer, at least one of drawing processing of an object arranged on the near side as viewed from the viewpoint of the plurality of model objects and filtering processing using the Z value are performed. May be.

  In this way, it is possible to perform an appropriate drawing process or a filter process on the near object based on the Z value finally generated in the Z buffer.

  In the image generation system, the program, and the information storage medium according to the present invention, the drawing unit refers to the Z value of the Z buffer when a plurality of model objects belong to the Kth drawing order rank. A plurality of model objects belonging to the Kth drawing order rank are drawn, the Z value of the Z buffer is cleared after drawing, and the model object of the Lth drawing order rank is drawn after clearing. Good.

  In this way, for a plurality of model objects belonging to the same drawing order rank, the hidden surface is appropriately erased using the Z buffer and the image is generated, so the variety degree of the generated image Can be increased.

  In addition, the image generation system, the program, and the information storage medium according to the present invention include a link information storage unit that stores link information for setting at least the number information of model objects belonging to each drawing order rank (link information storage). And the drawing unit may draw a plurality of model objects belonging to the Kth drawing order rank based on the link information.

  In this way, it is possible to realize appropriate drawing processing of the plurality of model objects while determining the number of the plurality of model objects belonging to the same drawing order rank based on the link information.

  In the image generation system, the program, and the information storage medium according to the present invention, a movement / motion process for performing control for moving / moving a plurality of model objects on the reference line on the movement field based on operation information from the operation unit. May be included (the computer may function as a movement / operation processing unit).

  Hereinafter, this embodiment will be described. In addition, this embodiment demonstrated below does not unduly limit the content of this invention described in the claim. In addition, all the configurations described in the present embodiment are not necessarily essential configuration requirements of the present invention.

1. Configuration FIG. 1 shows an example of a functional block diagram of an image generation system (game system) of the present embodiment. Note that the image generation system of the present embodiment may have a configuration in which some of the components (each unit) in FIG. 1 are omitted.

  The operation unit 160 is for a player to input operation data, and the function can be realized by a lever, a button, a steering, a microphone, a touch panel display, or a housing. The storage unit 170 is a work area such as the processing unit 100 or the communication unit 196 or a main memory, and its function can be realized by a RAM (VRAM) or the like.

  The information storage medium 180 (computer-readable medium) stores programs, data, and the like, and functions as an optical disk (CD, DVD), hard disk, memory card, memory cassette, magnetic disk, or memory ( ROM) or the like. The processing unit 100 performs various processes of the present embodiment based on a program (data) stored in the information storage medium 180. That is, the information storage medium 180 stores a program for causing a computer to function as each unit of the present embodiment (a program for causing a computer to execute the processing procedure of each unit).

  The display unit 190 outputs an image generated according to the present embodiment, and its function can be realized by a CRT, LCD (Liquid Crystal Display), touch panel display, HMD (Head Mount Display), or the like. The sound output unit 192 outputs the sound generated by the present embodiment, and its function can be realized by a speaker, headphones, or the like.

  The portable information storage device 194 stores player personal data, game save data, and the like, and examples of the portable information storage device 194 include a memory card and a portable game device. The communication unit 196 performs various controls for communicating with the outside (for example, a host device or other image generation system), and functions thereof are hardware such as various processors or communication ASICs, programs, and the like. It can be realized by.

  Note that a program (data) for causing a computer to function as each unit of the present embodiment is distributed from the information storage medium of the host device (server) to the information storage medium 180 (storage unit 170) via the network and communication unit 196. May be. Use of the information storage medium of such a host device (server) can also be included in the scope of the present invention.

  The processing unit 100 (processor) performs processing such as game processing, image generation processing, or sound generation processing based on operation data and programs from the operation unit 160. Here, as the game process, a process for starting a game when a game start condition is satisfied, a process for advancing the game, a process for placing an object such as a character or a map, a process for displaying an object, and a game result are calculated. There is a process or a process of ending a game when a game end condition is satisfied. The processing unit 100 performs various processes using the storage unit 170 as a work area. The functions of the processing unit 100 can be realized by hardware such as various processors (CPU, DSP, etc.), ASIC (gate array, etc.), and programs.

  The processing unit 100 includes an object space setting unit 110, a movement / motion processing unit 112, a virtual camera control unit 114, a drawing unit 120, and a sound generation unit 130. Note that some of these may be omitted.

  The object space setting unit 110 includes various objects (primitive surfaces such as polygons, free-form surfaces, and subdivision surfaces) representing display objects such as characters, cars, tanks, buildings, trees, columns, walls, and maps (terrain). (Object) is set in the object space. That is, the position and rotation angle (synonymous with direction and direction) of the object (model object) in the world coordinate system are determined, and the rotation angle (X, Y, Z axis around the position (X, Y, Z)) is determined. Arrange objects at (rotation angle).

  The movement / motion processing unit 112 performs a movement / motion calculation (movement / motion simulation) of an object (such as a character, a car, or an airplane). That is, an object (moving object) is moved in the object space or an object is moved based on operation data input by the player through the operation unit 160, a program (movement / motion algorithm), various data (motion data), or the like. Perform processing (motion, animation). Specifically, simulation processing for sequentially obtaining object movement information (position, rotation angle, speed, or acceleration) and motion information (position or rotation angle of each part object) every frame (1/60 seconds) I do. The frame (frame rate) is a unit of time for performing object movement / motion processing (simulation processing) and image generation processing.

  In the present embodiment, the movement / motion processing unit 112 (movement processing unit) determines a plurality of model objects (characters) as a reference on a movement field (movement map, game field) based on operation information from the operation unit 160. Control to move or operate on the line (moving line). For example, when the player instructs the left movement by the operation unit 160, the model object moves to the left on the reference line, and when the player instructs the right movement, the model object moves to the right. When the player instructs an attack using the operation unit 160, the model object (self character) operated by the player performs an action of attacking the enemy model object (enemy character).

  The virtual camera control unit 114 performs a virtual camera (viewpoint) control process for generating an image viewed from a given (arbitrary) viewpoint in the object space. Specifically, a process for controlling the position (X, Y, Z) or the rotation angle (rotation angle about the X, Y, Z axes) of the virtual camera (process for controlling the viewpoint position and the line-of-sight direction) is performed.

  For example, when an object (eg, character, ball, car) is photographed from behind using a virtual camera, the position or rotation angle of the virtual camera (the direction of the virtual camera is set so that the virtual camera follows changes in the position or rotation of the object. ) To control. In this case, the virtual camera can be controlled based on information such as the position, rotation angle, or speed of the object obtained by the movement / motion processing unit 112. Alternatively, the virtual camera may be controlled to rotate at a predetermined rotation angle or to move along a predetermined movement path. In this case, the virtual camera is controlled based on the virtual camera data for specifying the position (movement path) or rotation angle of the virtual camera.

  The drawing unit 120 performs drawing processing based on the results of various processing (game processing) performed by the processing unit 100, thereby generating an image and outputting the image to the display unit 190. In the case of generating a so-called three-dimensional game image, first, geometric processing such as coordinate transformation (world coordinate transformation, camera coordinate transformation), clipping processing, or perspective transformation is performed, and drawing data ( The position coordinates, texture coordinates, color data, normal vector, α value, etc.) of the vertexes of the primitive surface are created. Then, based on the drawing data (primitive surface data), the object (one or a plurality of primitive surfaces) after the perspective transformation (after the geometry processing) is stored in the drawing buffer 172 (frame buffer, work buffer, etc.) in pixel units. Can be drawn in a VRAM). Thereby, an image that can be seen from the virtual camera (given viewpoint) in the object space is generated. Note that the drawing process in the drawing unit 120 may be realized by a so-called pixel shader or vertex shader.

  The drawing unit 120 can perform texture mapping processing, hidden surface removal processing, and α blending processing.

  Here, the texture mapping process is a process of mapping a texture (texel value) stored in the texture storage unit 174 to an object. Specifically, the texture (surface properties such as color and α value) is read from the texture storage unit 174 using the texture coordinates set (given) at the vertices of the object (primitive surface). Then, a texture that is a two-dimensional image or pattern is mapped to the object. In this case, processing for associating pixels and texels, bilinear interpolation (texel interpolation), and the like are performed.

  The hidden surface removal processing is realized by, for example, a Z buffer method (depth comparison method, Z test) using a Z buffer 176 (depth buffer) in which the Z value (depth information) of each pixel is stored. That is, when drawing each pixel of the primitive surface of the object, the Z value (Z value in the camera coordinate system) stored in the Z buffer 176 is referred to. Then, the Z value of the referenced Z buffer 176 is compared with the Z value at the drawing target pixel on the primitive surface, and the Z value at the drawing target pixel is the front side when viewed from the virtual camera (for example, a large value) Z value), the drawing process for the pixel is performed and the Z value in the Z buffer 176 is updated to a new Z value.

  The α blending process is a process performed based on the α value (A value), and includes normal α blending, addition α blending, subtraction α blending, and the like. For example, in the case of normal α blending, the following processing is performed.

R _Q = (1−α) × R ₁ + α × R ₂
G _Q = (1−α) × G ₁ + α × G ₂
B _Q = (1−α) × B ₁ + α × B ₂
On the other hand, in the case of addition α blending, the following processing is performed.

R _Q = R ₁ + α × R ₂
G _Q = G ₁ + α × G ₂
B _Q = B ₁ + α × B ₂
In the case of subtractive α blending, the following processing is performed.

R _Q = R ₁ −α × R ₂
G _Q = G ₁ −α × G ₂
B _Q = B ₁ −α × B ₂
Here, R ₁ , G ₁ , and B ₁ are RGB components of an image (original image) already drawn in the drawing buffer 172 (frame buffer), and R ₂ , G ₂ , and B ₂ are drawing buffers 172. Are RGB components of the image to be drawn. R _Q , G _Q , and B _Q are RGB components of an image obtained by α blending. The α value is information that can be stored in association with each pixel (texel, dot), for example, plus alpha information other than color information. The α value can be used as translucency (equivalent to transparency and opacity) information, mask information, or bump information.

  In the present embodiment, the rank information storage unit 177 of the storage unit 170 stores rank information for setting (designating) the rank of the drawing order of model objects (objects composed of a plurality of part objects). The link information storage unit 178 stores link information for setting at least the number information of model objects belonging to (registered) each drawing order rank.

  The drawing unit 120 uses a frame buffer (drawing) to draw a plurality of model objects from a model object with a low drawing order rank to a model object with a high drawing order rank in a drawing order according to the rank information stored in the rank information storage unit 177. Drawing is performed in one buffer in the buffer 172). At this time, hidden surface removal is performed by the Z buffer method with reference to the Z value of the Z buffer 176. For example, the drawing unit 120 draws a model object having a drawing order rank of RANK = 0, then draws a model object of RANK = 1, and then draws a model object of RANK = 2. If there are a plurality of model objects belonging to the same drawing order rank, after drawing the plurality of model objects, the model object of the next drawing order rank is drawn.

  Then, the drawing unit 120 clears the Z value of the Z buffer 176 generated by, for example, drawing the model object of the Kth drawing order rank (after initialization), and then, more than the Kth drawing order rank. A model object of the Lth drawing order rank (K, L is an arbitrary integer satisfying 1 ≦ K <N, 1 <L ≦ N, and K <L) having a higher rank is drawn. For example, after clearing the Z value of the Z buffer 176 generated by drawing the model object with RANK = 0, the model object with RANK = 1 is drawn. Further, after clearing the Z value of the Z buffer 176 generated by drawing the model object of RANK = 1, the model object of RANK = 2 is drawn.

  More specifically, the drawing unit 120 draws a background object before drawing a plurality of model objects, and uses the Z value of the Z buffer 176 generated by drawing the background object as a work buffer (in the drawing buffer 172). It is copied (saved) in one buffer). Then, the Z value of the Z buffer 176 generated by drawing the model object of the Kth drawing order rank is combined (written) in the work buffer, and the Z value of the Z buffer 176 is cleared after the combining. For example, a model object with RANK = 0 is drawn, and the Z value of the Z buffer 176 generated by the drawing is combined with the work buffer. That is, the Z value plane generated in the work buffer by drawing the background object and the Z value plane of the Z buffer 176 generated by drawing the model object with RANK = 0 are combined. Then, the Z buffer 176 is cleared after the composition. Next, a model object of RANK = 1 is drawn, the Z value of the Z buffer 176 generated by the drawing is combined with the work buffer, and the Z buffer 176 is cleared after the combination.

  A background object to be drawn before drawing a plurality of model objects is an object on the back side as viewed from the viewpoint of the model object, an object constituting a moving field (ground), or the like. That is, for example, when a semi-transparent process is required for a model object, the object may be written behind the model object.

  The drawing unit 120 copies the Z value generated in the work buffer to the Z buffer 176 after drawing of all the plurality of model objects (all model objects for which the drawing order rank is set) is completed. Then, based on the Z value copied to the Z buffer 176, drawing processing of an object (for example, a tree) arranged on the near side as viewed from the viewpoint of the model object is performed. Alternatively, filter processing (depth of field, glare, fog filter, etc.) using the Z value stored in the Z buffer is performed. The filter processing in this case is performed by the filter processing unit 122 included in the drawing unit 120.

  The sound generation unit 130 performs sound processing based on the results of various processes performed by the processing unit 100, generates game sounds such as BGM, sound effects, or sounds, and outputs the game sounds to the sound output unit 192.

  Note that the image generation system of the present embodiment may be a system dedicated to the single player mode in which only one player can play, or may be a system having a multiplayer mode in which a plurality of players can play. Further, when a plurality of players play, game images and game sounds to be provided to the plurality of players may be generated using one terminal, or connected via a network (transmission line, communication line) or the like. Alternatively, it may be generated by distributed processing using a plurality of terminals (game machine, mobile phone).

2. Next, the method of this embodiment will be described with reference to the drawings.

2.1 Problems in which model objects overlap each other Some role-playing games and fighting games follow a conventional two-dimensional game movement control system. For example, in FIG. 2A, model objects OB1 and OB2 (characters in a narrow sense) move on a reference line BL (movement line). Specifically, OB1 moves to the left and right on the reference line BL by the operation of the first player, and OB2 moves to the left and right on the reference line BL by the operation of the second player or computer. And if OB1 and OB2 approach and a player performs attack operation, the battle between OB1 and OB2 will be performed. The reference line BL is a line (for example, ZW = 0) in which the ZW in the world coordinate system is constant, for example. However, the reference line BL may be a line in which ZW is not constant, or may be a curved line as well as a straight line.

  In a normal three-dimensional game, it is common to employ a movement control system in which model objects OB1 and OB2 can move in a free direction on a movement field (ground, map, game space). However, in this movement control system, the degree of freedom of movement of OB1 and OB2 is too high, and the player may be confused by the operation.

  In this regard, according to the movement control system as shown in FIG. 2A, since the degree of freedom of movement of the model objects OB1 and OB2 is only in the horizontal direction (direction on the XW axis), the operation of the player is simplified. it can. In particular, it is desirable for a player who is accustomed to a conventional two-dimensional game movement control system to follow the movement control system as shown in FIG. 2A even for a three-dimensional game.

  However, in the movement control system of FIG. 2A, when the model objects OB1 and OB2 are arranged at the same position (same XW and ZW coordinates) or approach each other, as shown in FIG. 3, the polygons of OB1 and OB2 There is a problem that the two cross each other and overlap each other. For example, in a normal three-dimensional game movement control system, each model object OB1, OB2 has a hit box with a simplified shape. Then, hit check processing between these hit boxes is performed, and OB1 and OB2 are not allowed to be arranged at the same position, so that the problem as shown in FIG. 3 does not occur.

  However, in the movement control system of FIG. 2A, it may be permitted that the model objects OB1 and OB2 are arranged at the same position. In particular, when a plurality of model objects (characters) form a party, the plurality of model objects are often arranged at the same position, so that a problem as shown in FIG. 3 frequently occurs.

  In this case, as one method for solving such a problem in the movement control system of FIG. 2A, a method of shifting the ZW of the model objects OB1 and OB2 as shown in FIG. For example, in FIG. 2B, the ZW of the model object OB1 is shifted in the negative direction, and the ZW of OB2 is shifted in the positive direction.

  However, in the method of FIG. 2B, the perspectives of the model objects OB1 and OB2 are different. That is, as shown in FIG. 2B, when ZW at the viewpoint position of the virtual camera VC is positive and the line-of-sight direction is in the negative direction of ZW, OB1 is viewed from the virtual camera VC (viewpoint). It looks small and OB2 looks big. In particular, when a plurality of model objects on a team form a party and are lined up at the same position, the method of FIG. 2 (B) makes these model objects look different sizes and looks bad. .

2.2 Drawing Based on Rank Information Accordingly, in this embodiment, the concept of rank information RANK for setting (designating and determining) the rank of the drawing order of a plurality of model objects is introduced. For example, in FIG. 4, the model object OB1 belongs to the lowest RANK = 0 (Kth drawing order rank in a broad sense), and RANK = 1 (Lth in a broad sense) has a higher drawing order rank than RANK = 0. OB2 belongs to (drawing order rank). A plurality of model objects OB3 and OB4 belong to the next RANK = 2, OB5, OB6, and OB7 belong to RANK = 3, and OB8 and OB9 belong to RANK = 4.

  In FIG. 4, link information LINK is information for setting (designating or determining) at least the number information of model objects belonging to each drawing order rank. RANK corresponds to a box that can register model objects, and one or more model objects corresponding to LINK can be registered in each RANK. For example, in FIG. 4, RAN with LINK = 0 is registered in RANK = 0. In RANK = 1, OB2 with LINK = 0 is registered. In RANK = 2, OB3 with LINK = 0 and OB4 with LINK = 1 are registered. By referring to the LINK set in each RANK, it is possible to know the number information of the model objects belonging to each RANK. The form of rank information and link information is not limited to that shown in FIG. 4 and various modifications can be made.

  In the present embodiment, model objects are drawn from a model object with a low drawing order rank to a model object with a high drawing order in a drawing order according to the rank information RANK. For example, in FIG. 4, OB1 with RANK = 0 is first drawn, and then OB2 with RANK = 1 is drawn. Then, OB3 and OB4 with RANK = 2 are drawn, and then OB5, OB6 and OB7 with RANK = 3 are drawn. Next, OB8 and OB9 of RANK = 4 are drawn. Note that the drawing order of a plurality of model objects within the same rank is arbitrary. For example, the drawing order of OB5, OB6, and OB7 when RANK = 3 is arbitrary.

  In this embodiment, after clearing the Z value of the Z buffer generated by drawing the model object of the Kth drawing order rank, the Lth drawing order rank that is higher than the Kth drawing order rank. The model object is drawn. For example, as shown in FIG. 5, after clearing the Z value of the Z buffer generated by drawing OB1 with RANK = 0 (Kth drawing order rank), the next RANK = 1 (Lth drawing order). OB2 of (rank) is drawn. For example, in a system in which the Z value (camera coordinate system) decreases as the distance from the virtual camera increases, the Z buffer can be cleared by setting the Z value of the Z buffer to Z = 0. On the other hand, in a system in which the Z value increases with increasing distance from the virtual camera, the Z buffer can be cleared by setting the Z value of the Z buffer to Z = infinity.

  More specifically, in the present embodiment, as indicated by A1 in FIG. 6, a Z object generated by drawing a background object (distant view, moving field object) before drawing a plurality of model objects and drawing the background object. The Z value of the buffer is copied (saved) to the work buffer. Then, as shown at A2, the Z value of the Z buffer generated by drawing OB1 with RANK = 0 (Kth drawing order rank) is combined with the work buffer. Here, the synthesis of the Z value in the work buffer can be realized by updating only the Z value updated by drawing the model object (the area in which the Z value has been updated) on the work buffer.

  Next, as indicated by A3, the Z value of the Z buffer is cleared after the composition to the work buffer. Then, as shown in A4, after clearing the Z value of the Z buffer, OB2 of the next RANK = 1 (Lth drawing order rank) is drawn, and the Z value of the Z buffer generated by this drawing is combined with the work buffer. To do. Then, after the composition, the Z value of the Z buffer is cleared, and the next RANK = 2 OB3 and OB4 are drawn.

  Then, after drawing of all the model objects OB1 to OB9 for which RANK is set, the Z value generated in the work buffer is copied and written back to the Z buffer. Then, based on the Z value copied to the Z buffer, a drawing process is performed for an object arranged on the near side as viewed from the viewpoint of the plurality of model objects. Alternatively, filter processing using the Z value is performed.

  As a filter process in this case, a Z value (Z plane) is converted into an α value (α plane), and a filter process based on the α value obtained by this conversion can be considered. For example, based on the α value obtained by the conversion, the original image (the image obtained by drawing the object after the perspective conversion) and the blurred image are α-blended, so that the depth-of-field filtering process is performed. realizable. Also, fog filtering processing can be realized by combining the original image and the fog color (given color) based on the α value obtained by the conversion. Note that the Z value may be converted into color information, and filter processing based on the color information obtained by this conversion may be performed. The process of converting the Z value into the α value or the color information can be realized by setting the Z value to the index number of the color lookup table CLUT and performing index color / texture mapping using the CLUT.

  FIG. 7 shows an example of an image generated by the method of this embodiment. As shown in FIG. 7, according to the method of the present embodiment, even if the model objects OB1 and OB2 are arranged at the same position (substantially the same position), they are properly erased and displayed. Thus, the problem of FIG. 3 can be solved.

  That is, in FIG. 7, OB1 belongs to RANK = 0, OB2 belongs to RANK = 1, and OB2 has a higher drawing order rank. Therefore, after OB1 is drawn, the Z buffer is cleared and OB2 is drawn after that. For this reason, even if OB1 and OB2 are arranged at the same position (same XW and ZW coordinates), OB2 is always displayed on the near side, and OB1 and OB2 appear to overlap each other. Can be resolved. Therefore, even in the movement control system as shown in FIG. In particular, when OB1 and OB2 form a party with each other, in many cases, OB1 and OB2 face the same direction and are arranged at the same position (substantially the same position) in FIG. According to the method of the embodiment, the occurrence of defects can be effectively prevented.

  2B, the perspectives of OB1 and OB2 are different when the virtual camera VC is arranged as shown in FIG. 2B. There is a problem that OB1 appears small and OB2 appears large.

  On the other hand, according to the method of the present embodiment, it is not necessary to shift the ZW of OB1 and OB2. Accordingly, as shown in FIG. 7, even if OB1 and OB2 are arranged at the same position (substantially the same position), the perspectives of these OB1 and OB2 are the same. Therefore, it is possible to prevent a problem that OB1 looks small and OB2 appears large. Note that the model object movement control method in the present embodiment is not limited to the method shown in FIG. For example, control for moving the model object on a reference line where ZW is not constant may be performed, or control for moving the model object without being limited to the reference line may be performed.

  In the present embodiment, the drawing order rank of the model object is controlled based on the rank information RANK. Therefore, for example, as shown in FIG. 8, it is possible to easily control the display of OB1 on the front side and the display of OB2 on the back side, contrary to FIG. That is, in FIG. 4, since OB1 is set to RANK = 0 and OB2 is set to RANK = 1, an image as shown in FIG. 7 is displayed. On the other hand, if OB2 is set to RANK = 0 and OB1 is set to RANK = 1, an image as shown in FIG. 8 is displayed.

  For example, when a plurality of model objects form a party and fight against an enemy, it is desirable to make the model objects that perform effective techniques such as special techniques stand out. In this embodiment, since the concept of rank information RANK is introduced, such display control can be easily performed. For example, when OB2 takes out a special technique, if RAN of OB2 is set to a high value, OB2 is displayed on the near side as shown in FIG. This makes it possible to effectively show the player the special technique that OB2 delivers. On the other hand, when OB1 takes out a special technique, if RAN of OB1 is set to a high value, OB1 is displayed on the near side as shown in FIG. This makes it possible to effectively show the player the special technique that OB1 delivers.

  Further, according to the method of the present embodiment, as shown in FIG. 9, even when not only two but also three or more model objects are arranged at the same position, an image having no defect can be generated. For example, in FIG. 9, OB1 is set to RANK = 0, OB2 is set to RANK = 1, and OB3 is set to RANK = 2. Therefore, OB1 is displayed on the farthest side, OB3 is displayed on the foremost side, and OB2 is displayed in the meantime. As described above, when three or more model objects are arranged, if the method as shown in FIG. 2B is adopted, a situation in which the difference in size of these model objects becomes more noticeable occurs. According to the embodiment, such a situation can be prevented.

  Further, according to the present embodiment, as described with reference to FIG. 6, the Z value generated by drawing the background is saved in the work buffer, and the Z value obtained by generating each model object is stored in this work buffer. A method is employed in which the Z values synthesized and finally generated in the work buffer are copied back to the Z buffer. Therefore, by using the Z value of the final Z buffer after copying, it is possible to perform an appropriate hidden surface erasing process on the object drawn after the model object is drawn. It is also possible to perform appropriate filter processing using the Z value of the Z buffer after copying.

  That is, in this embodiment, the Z buffer is cleared every time a model object is drawn. Therefore, if the method of copying and saving the Z value of the Z buffer to the work buffer is not adopted, an appropriate hidden surface removal process of the object drawn after the drawing of the model object, or an appropriate value using the Z value of the Z buffer is used. Although there is a possibility that a situation where the filter processing cannot be realized may occur, such a situation can be prevented if the method of FIG. 6 is adopted.

  Further, according to the present embodiment, since a plurality of model objects can belong (register) to the same RANK (Kth drawing order rank), an image as shown in FIG. 10 can be generated. That is, in FIGS. 4 and 10, the model objects OB3 and OB4 belong to the same RANK = 2. In this case, these OB3 and OB4 are drawn with reference to the Z buffer, and then the Z value of the Z buffer is cleared. After the Z buffer is cleared, the next RAN = 3 OB5, OB6, and OB7 are drawn.

  In this way, by allowing a plurality of model objects to belong to the same RANK, more various image representations are possible. For example, in a scene where model objects (characters) battle each other, it is preferable to generate an image in which these objects are displayed in an overlapping manner, rather than generating an image in which OB2 is always visible in front of OB1, as shown in FIG. There is a case.

  Even in such a case, according to the present embodiment, by registering OB3 and OB4 in the same RANK, it is possible to generate an image in which OB3 and OB4 are overlapped as shown in FIG. According to the display of FIG. 10, it is possible to generate an image that looks as if OB3 and OB4 are fighting with arms crossed. Further, for example, when OB3 and OB4 have weapons, hidden surface elimination between these weapons is appropriately performed. Therefore, a natural and realistic image can be generated and the variety of the generated image can be increased.

  When a plurality of model objects belong to the same RANK, the plurality of model objects may be drawn based on the link information LINK as shown in FIG. That is, the number of model objects that need to be drawn in the RANK is determined based on the LINK. Then, after the drawing of the number of model objects is completed, the Z value of the Z buffer is cleared, and the next RANK model object is drawn. Further, when generating an image as shown in FIG. 10, it is possible to employ a method of slightly shifting the Z value of the model object as shown in FIG.

2.3 Detailed Processing Example Next, a detailed processing example of this embodiment will be described with reference to the flowchart of FIG.

  First, a background object (an object behind the character) is drawn (step S1). Examples of the background object include a distant view object such as a sky and a mountain, and a moving field object (map object) such as the ground. Then, as described in A1 of FIG. 6, the Z value of the Z buffer is copied to the work buffer and saved (step S2).

  Next, RANK = 0 is set (step S3), and the Z value of the Z buffer is cleared (step S4). Further, LINK = 0 is set (step S5).

  Next, the current LINK character (model object) is drawn (step S6). For example, when LINK is set as shown in FIG. 4, OB1 with RANK = 0 is drawn. Then, after drawing, LINK is incremented to LINK + 1 (step S7).

  Next, it is determined whether or not drawing of all characters in the rank has been completed (step S8). If not completed, the process returns to step S6, and the processes of steps S6 to S8 are performed for the number of characters. repeat. For example, in FIG. 4, when RANK = 2, the processes of steps S6 to S8 are repeated twice, and when RANK = 3, the processes are repeated three times.

  When drawing of all characters in RANK is completed, the contents of the current Z buffer and the contents of the work buffer are synthesized as described in A2 and A4 of FIG. 6 (step S9). Then, RANK is incremented to RANK + 1 (step S10).

  Next, it is determined whether or not drawing for all ranks has been completed (step S11). If not completed, the process returns to step S4. Then, the processes in steps S4 to S11 are repeated until drawing for all ranks is completed.

  When drawing for all ranks is completed, the Z value of the work buffer is copied (overwritten) to the Z buffer as described in A5 of FIG. 6 (step S12). Then, a background object that is an object on the near side of the character is drawn (step S13). Then, if necessary, filter processing using the Z value of the Z buffer is performed (step S14).

3. Hardware Configuration FIG. 13 shows an example of a hardware configuration that can realize this embodiment. The main processor 900 operates based on a program stored in a CD 982 (information storage medium), a program downloaded via the communication interface 990, a program stored in the ROM 950, or the like, and includes game processing, image processing, sound processing, and the like. Execute. The coprocessor 902 assists the processing of the main processor 900, and executes matrix operation (vector operation) at high speed. For example, when a matrix calculation process is required for a physical simulation for moving or moving an object, a program operating on the main processor 900 instructs (requests) the process to the coprocessor 902.

  The geometry processor 904 performs geometry processing such as coordinate conversion, perspective conversion, light source calculation, and curved surface generation based on an instruction from a program operating on the main processor 900, and executes matrix calculation at high speed. The data decompression processor 906 performs decoding processing of the compressed image data and sound data and accelerates the decoding processing of the main processor 900. Thereby, a moving image compressed by the MPEG method or the like can be displayed on the opening screen or the game screen.

  The drawing processor 910 executes drawing (rendering) processing of an object composed of primitive surfaces such as polygons and curved surfaces. When drawing an object, the main processor 900 uses the DMA controller 970 to pass the drawing data to the drawing processor 910 and, if necessary, transfers the texture to the texture storage unit 924. Then, the drawing processor 910 draws the object in the frame buffer 922 while performing hidden surface removal using a Z buffer or the like based on the drawing data and texture. The drawing processor 910 also performs α blending (translucent processing), depth cueing, mip mapping, fog processing, bilinear filtering, trilinear filtering, anti-aliasing, shading processing, and the like. When an image for one frame is written in the frame buffer 922, the image is displayed on the display 912.

  The sound processor 930 includes a multi-channel ADPCM sound source and the like, generates game sounds such as BGM, sound effects, and sounds, and outputs them through the speaker 932. Data from the game controller 942 and the memory card 944 is input via the serial interface 940.

  The ROM 950 stores system programs and the like. In the case of an arcade game system, the ROM 950 functions as an information storage medium, and various programs are stored in the ROM 950. A hard disk may be used instead of the ROM 950. The RAM 960 is a work area for various processors. The DMA controller 970 controls DMA transfer between the processor and the memory. The CD drive 980 accesses a CD 982 in which programs, image data, sound data, and the like are stored. The communication interface 990 performs data transfer with the outside via a network (communication line, high-speed serial bus).

  Note that the processing of each unit (each unit) in the present embodiment may be realized entirely by hardware, or may be realized by a program stored in an information storage medium or a program distributed via a communication interface. May be. Alternatively, it may be realized by both hardware and a program.

  When the processing of each unit of the present embodiment is realized by both hardware and a program, a program for causing the hardware (computer) to function as each unit of the present embodiment is stored in the information storage medium. . More specifically, the program instructs the processors 902, 904, 906, 910, and 930, which are hardware, and passes data if necessary. Each processor 902, 904, 906, 910, 930 realizes the processing of each unit of the present invention based on the instruction and the passed data.

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term (frame buffer, work buffer, character, etc.) written together with a different term (drawing buffer, model object, etc.) more broadly or synonymously at least once in the specification or drawing is used anywhere in the specification or drawing. Can also be replaced by the different terms.

  Also, the form of rank information, link information, drawing method of model object, setting method of rank to model object, update / clearing method of Z buffer, etc. are not limited to those described in this embodiment, Techniques equivalent to these are also included in the scope of the present invention. For example, it is possible to adopt a method that does not perform the processing of A1, A2, A4, and A5 in FIG.

  The present invention can be applied to various games. Further, the present invention is applied to various image generation systems such as a business game system, a home game system, a large attraction system in which a large number of players participate, a simulator, a multimedia terminal, a system board for generating game images, and a mobile phone. it can.

The example of a functional block diagram of the image generation system of this embodiment. 2A and 2B are explanatory diagrams of a movement control method and a method for solving the problem. The example of the malfunction image by the conventional method. Explanatory drawing of the rank information of this embodiment, and link information. Explanatory drawing of the method of this embodiment. Explanatory drawing of the detailed example of the method of this embodiment. The example of the image produced | generated by this embodiment. The example of the image produced | generated by this embodiment. The example of the image produced | generated by this embodiment. The example of the image produced | generated by this embodiment. The detailed example of the process of this embodiment. The detailed example of the process of this embodiment. Hardware configuration example.

Explanation of symbols

OB1 to OB9 model object 100 processing unit, 110 object space setting unit, 112 movement / motion processing unit,
114 virtual camera control unit, 120 drawing unit, 122 filter processing unit,
130 sound generation unit, 160 operation unit, 170 storage unit, 172 drawing buffer,
174 texture storage unit, 176 Z buffer, 177 rank information storage unit,
178 Link information storage unit, 180 information storage medium, 190 display unit,
192 sound output unit, 194 portable information storage device, 196 communication unit

Claims (8)

A program for generating an image,
A rank information storage unit that stores rank information for setting the rank of the drawing order of a plurality of model objects;
A Z buffer for storing the Z value of each pixel;
As a drawing unit that sequentially draws the plurality of model objects from a model object having a low drawing order rank to a model object having a high drawing order rank in the drawing order according to the rank information, with reference to the Z value of the Z buffer. ,
Make the computer work,
The drawing unit
After clearing the Z value of the Z buffer generated by drawing the model object of the Kth drawing order rank, the Lth drawing order rank (K, L) having a higher rank than the Kth drawing order rank Is a program that draws a model object of 1 ≦ K <N, 1 <L ≦ N, and K <L. In claim 1,
The drawing unit
Draw a background object before drawing the plurality of model objects, copy the Z value of the Z buffer generated by drawing the background object to a work buffer,
A program characterized in that the Z value of the Z buffer generated by drawing the model object of the Kth drawing order rank is combined with the work buffer, and the Z value of the Z buffer is cleared after the combining. . In claim 2,
The drawing unit
After the drawing of all the plurality of model objects is completed, the Z value generated in the work buffer is copied to the Z buffer,
Based on the Z value copied to the Z buffer, at least one of drawing processing of an object arranged closer to the viewpoint than the plurality of model objects and filtering processing using the Z value is performed. A featured program. In any one of Claims 1 thru | or 3,
The drawing unit
When a plurality of model objects belong to the Kth drawing order rank, a plurality of model objects belonging to the Kth drawing order rank are drawn with reference to the Z value of the Z buffer, and after drawing A program that clears the Z value of the Z buffer and draws the model object of the Lth drawing order rank after clearing. In claim 4,
As a link information storage unit for storing link information for setting at least the number information of model objects belonging to each drawing order rank,
Make the computer work,
The drawing unit
A program for drawing a plurality of model objects belonging to the Kth drawing order rank based on the link information. In any one of Claims 1 thru | or 5,
Based on operation information from the operation unit, as a movement / motion processing unit that performs control to move / operate multiple model objects on the reference line on the movement field,
A program characterized by causing a computer to function.   A computer-readable information storage medium, wherein the program according to any one of claims 1 to 6 is stored. An image generation system for generating an image,
A rank information storage unit that stores rank information for setting the rank of the drawing order of a plurality of model objects;
A Z buffer for storing the Z value of each pixel;
A drawing unit that sequentially draws the plurality of model objects in a drawing order according to the rank information from a model object having a low drawing order rank to a model object having a high drawing order rank while referring to a Z value of the Z buffer; Including
The drawing unit
After clearing the Z value of the Z buffer generated by drawing the model object of the Kth drawing order rank, the Lth drawing order rank (K, L) having a higher rank than the Kth drawing order rank Is a model object of 1 ≦ K <N, 1 <L ≦ N, and K <L.