JP2006346507A - Game apparatus and image processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a game apparatus where a specific object such as a player character can be displayed at all times without damaging the atmosphere of a game field as far as possible. <P>SOLUTION: A character object CH1 is projected first on a screen plane, and drawing is carried out with a circular area with the position of the character object CH1 projected on the screen plane as a center as a mask area. Picture data obtained like this is stored in a main memory as mask data, and utilized when drawing each object in a virtual game space. A transmission flag is set previously to respective field objects OB1 to OB3. The field object OB1 whose transmission flag is 1 is drawn using the mask data, and the character object CH1 and the field objects OB2 and OB3 whose transmission flags are 0 are drawn normally. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a game device and an image processing program, and in particular, when a building image drawn in, for example, a three-dimensional virtual game space and a player character image operated by the player are displayed together, the player character The present invention relates to a game apparatus and an image processing program that have solved the inconvenience of being hidden behind a building.

  In a game developed in a three-dimensional virtual game space, for example, when a player character operated by a player moves between buildings, the player character may be hidden in the building on the game screen. In such a case, it has been common to display the player character by moving the viewpoint. However, depending on the game, it may be preferable to always display a game image as if the virtual game space was viewed from the same direction without moving the viewpoint.

  In the technique described in Patent Document 1, the player character can always be visually recognized on the display screen by performing the permeation process on the wall and the floor only when the player character is overlapped with or near the display position of the player character. ing.

In the technique described in Patent Document 2, it is determined whether or not an obstacle is hiding the subject, and only when the obstacle is hiding the subject, a transparent process is performed on the obstacle, thereby allowing the player on the display screen. The character is always visible.
Japanese Patent No. 2902352 Japanese Patent No. 3141737

  However, in the technique described in Patent Document 1, when the player character is hidden behind the wall of the building, the entire wall is transparently processed, so that the game field atmosphere is greatly changed. Even in the technique described in Patent Document 2, when an object is hidden behind an obstacle, the entire obstacle is transparently processed, and the obstacle that has been displayed disappears suddenly. It will change a lot. In any technique, for each object such as a wall or an obstacle, it is determined whether or not the player character (or subject) is hidden based on the positional relationship with the player character (or subject) or viewpoint. Each object needs to be drawn, and the processing load for determination increases as the number of objects increases.

  Therefore, a main object of the present invention is to provide a game apparatus and an image processing program capable of displaying a specific object such as a player character so as to be always visible without impairing the atmosphere of the game field as much as possible. .

  Another object of the present invention is to appropriately transmit objects such as walls and obstacles without determining whether or not the player character is hidden based on the positional relationship with the player character and the viewpoint. It is to provide a novel game device and an image processing program that can be processed and displayed so that a specific object such as a player character can be visually recognized.

  In order to solve the above problems, the present invention employs the following configuration. Note that the reference numerals, figure numbers, and supplementary explanations in parentheses show the correspondence with the drawings in order to help understanding of the present invention, and do not limit the scope of the present invention.

According to the first aspect of the present invention, one or more first objects and one or more second objects in a three-dimensional virtual game space are displayed by performing perspective projection conversion based on the viewpoint set in the virtual game space. An image processing program for causing a computer (24, 26) of a game device to execute a process of drawing a game image to be displayed on a screen in a drawing buffer area. This game program is stored on the computer in an arrangement position determination step (S10, S14), a calculation step (S24), a mask data generation step (S26), a first object drawing step (S38), and a second object drawing step (S36). Is executed.
The arrangement position determining step arranges the first three-dimensional coordinates and the second objects (OB1, OB2,...) For arranging the first objects (CH1, CH2,...) In the three-dimensional virtual game space. To determine the second three-dimensional arrangement coordinates. Here, the calculation step calculates the two-dimensional coordinates on the display screen by subjecting the first three-dimensional arrangement coordinates to perspective projection conversion based on the viewpoint (FIG. 11). In the mask data generation step, mask data for one screen in which a mask image (an image showing a mask area) having a predetermined shape is drawn at a position in the drawing buffer area corresponding to the two-dimensional coordinates on the display screen (FIG. 12, FIG. 14, 19, 34, and 38). In the first object drawing step, when the first object arranged at the first three-dimensional coordinate is perspective-projected and drawn in the drawing buffer area, the first object is drawn in the drawing buffer area without referring to the mask data. To draw. In the second object drawing step, when the second object arranged at the second three-dimensional coordinate is perspective-projected and drawn in the drawing buffer area, a portion overlapping the mask image is referred to by referring to the mask data The second object is drawn by changing the transmittance of the second object in comparison with the portion not overlapping the mask image (FIG. 13).

  The invention according to claim 2 is the image according to claim 1, wherein the mask image is an image whose color density becomes lighter or darker from the center toward the periphery (FIGS. 14 and 38). In the second object drawing step, the second object is drawn so that the transmittance of the second object changes in accordance with the color density of the mask image at the portion where the mask image and the second object overlap (FIG. 15, FIG. 15). 16).

  According to the first aspect of the present invention, the first three-dimensional coordinates of the first object are perspective-projected, mask data corresponding to one screen is created based on the two-dimensional coordinates after the conversion, and the second The mask data is referred to when the object is drawn, and the transmittance of the second object is changed for the overlapping portion with the mask image. As a result, since there is no process for determining whether or not the first object and the second object overlap, the processing load can be reduced.

  According to the second aspect of the present invention, the mask image has a color density that becomes lighter or darker toward the periphery, and the portion of the second object that corresponds to the color density of the mask image in a portion where the mask image overlaps the second object. The transmittance changes gradually. As a result, it is possible to suppress unnatural appearance due to a part of the second object being transparently displayed.

(First embodiment)
Hereinafter, a game system according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an external view showing a configuration of a game system according to an embodiment of the present invention. As shown in FIG. 1, the game system 10 includes a monitor 12, a game machine body 14, an optical disk 16, a memory card 18, and a controller 20. The optical disc 16 and the external memory card 18 are detachably attached to the game machine body 14. The controller 20 is connected to one of a plurality (four in FIG. 1) of controller port connectors provided on the game machine body 14 via a communication cable. The monitor 12 is connected to the game machine main body 14 by an AV cable or the like. The communication between the game machine body 14 and the controller 20 may be wireless communication.

  The controller 20 is an input device for a player to perform an input operation related to a game, and has a plurality of operation switches. The controller 20 outputs operation data indicating the state of the operation switch to the game machine body 14. The player can operate or move the player character appearing in the game by operating the controller 20.

  The optical disk 16 stores game programs and game data in a fixed manner. When the player plays the game, the optical disc 16 is mounted on the game machine body 14. As a means for storing the game program or the like, any external storage medium such as a DVD-ROM, a CD-ROM, an MO, a memory card, and a ROM cartridge can be used instead of the optical disc 16.

  The game machine body 14 reads a game program recorded on the optical disc 16 and performs processing according to the read game program.

  The monitor 12 displays a game image on the screen based on the video signal output from the game machine body 14. The monitor 12 is provided with a speaker 22, and the speaker 22 outputs a game sound based on an audio signal output from the game machine body 14.

  The memory card 18 includes a rewritable storage medium such as a flash memory as a backup memory, and game save data and the like are recorded in the backup memory.

  FIG. 2 is a block diagram showing an internal configuration of the game machine main body 14. Hereinafter, each part of the game machine body 14 will be described in more detail with reference to FIG.

  The game machine body 14 is provided with a CPU 24 and a memory controller 34 connected thereto. The memory controller 34 is connected to a GPU (graphics processing unit) 26, a main memory 28, a DSP (Digital Signal Processor) 30, and various interfaces. The memory controller 34 controls data transfer between these components.

  At the start of the game, first, the disk drive 46 drives the optical disk 16 mounted on the game machine body 14. The game program stored in the optical disc 16 is read into the main memory 28 via the disc I / F (interface) 44 and the memory controller 34. The game is started when the CPU 24 executes the game program loaded in the main memory 28. When the player performs an input operation using the controller 20 after the game is started, operation data is output from the controller 20 to the game machine body 14. Operation data output from the controller 20 is input to the CPU 24 via the controller I / F 36 and the memory controller 34. The CPU 24 performs a game process based on the input operation data. Game images are generated mainly by the GPU 26, and a DSP 30 is mainly used for generating game sounds. An ARAM (Audio RAM) 32 is used for storing an audio signal.

  The GPU 26 performs calculations related to the coordinates of an object placed in the three-dimensional virtual game space (for example, rotation, enlargement / reduction, transformation of the object, coordinate conversion from the world coordinate system to the camera coordinate system or the screen coordinate system), Further, a game image is generated by drawing an object projected on the screen plane based on texture data or the like (determining the color of a pixel corresponding to the object and writing it in a color buffer). The color buffer is a memory area reserved for holding game image data (RGB data) to be displayed on the monitor 12. In addition to the color buffer, the GPU 26 uses a Z buffer for holding the distance from the viewpoint to the object drawn in the color buffer, or a stencil buffer for the shadow volume technique, if necessary. Generate.

  3 and 4 show a memory map of the main memory 28. FIG. In particular, FIG. 3 is a memory map related to a program, and FIG. 4 is a memory map related to data.

  In FIG. 3, a main game 28 is loaded with a game main program 48, an object movement control program 50, and an image processing program 52 from the optical disc 16.

  The object movement control program 50 is a program for moving an object existing in the three-dimensional virtual game space according to a predetermined algorithm or a user instruction. The image processing program 52 includes a mask generation program 54, a projection program 56, a drawing program 58, and a display control program 60. The mask generation program is a program for causing the CPU 24 and the GPU 26 to generate mask data to be described later. The projection program 56 is a program for causing the CPU 24 and the GPU 26 to project an object existing in the virtual game space onto a predetermined screen plane. Projection methods include perspective projection and parallel projection. The drawing program 58 is a program for causing the CPU 24 or the GPU 26 to draw an object existing in the virtual game space (that is, to write the color of the object in the color buffer). The display control program 60 is a program for causing the CPU 24 or the GPU 26 to output a video signal to the monitor 12 at a constant period based on the image data stored in the color buffer.

  In FIG. 4, the main memory 28 stores an area used as the operation data buffer 62, an area used as the color buffer 64, an area for storing data related to the character object, and data related to the field object. An area for storing mask data 86 to be described later, and an area for storing other data.

  The operation data buffer 62 is a storage area for temporarily storing operation data output from the controller 20. The color buffer 64 is a storage area for temporarily storing color data of the game image displayed on the monitor 12.

  A character object is an object that represents a character that exists in the virtual game space. A player character that is operated by a player, or a non-player character that cannot be operated by the player but controls movement on the computer side in accordance with the movement of the player character. Set as In the present embodiment, it is assumed that there are a plurality of character objects (CH1, CH2, CH3,...) In the virtual game space. In the main memory 28, for each character object, position data 66 indicating the position (three-dimensional coordinates) of the character object in the virtual game space, polygon data 68 defining the shape of the character object, and a pattern of the surface of the character object are defined. Texture data 70 to be stored is held.

  The field object is an object that constitutes a field of the virtual game space, and specifically, a building, a wall, a ground, a road, etc. existing in the virtual game space. In the present embodiment, it is assumed that a plurality of field objects (OB1, OB2, OB3,...) Exist in the virtual game space. The main memory 28 defines, for each field object, position data 78 indicating the position (three-dimensional coordinates) of the field object in the virtual game space, polygon data 80 defining the shape of the field object, and the surface pattern of the field object. Texture data 82 and a transparency flag 84 described later are held.

  5 and 6 are game screen examples according to the first embodiment of the present invention. In FIG. 5, a character object CH1 and field objects OB1 to OB3 arranged in the virtual game space are displayed. When the character object CH1 moves from the position in FIG. 5 in the direction of the arrow, as shown in FIG. 6, only a predetermined area centering on the character object CH1 becomes transparent in the field object OB1, and as a result, the character object CH1 Even when the user moves behind the field object OB1, the user can visually recognize the character object CH1.

  Hereinafter, the flow of processing of the CPU 24 or the GPU 26 executed based on the various programs shown in FIG. 3 will be described with reference to the flowcharts of FIGS.

  In FIG. 7, when the main process is started, initial setting is first performed in step S10. Here, for example, a viewpoint, an object, and a light source are arranged at an initial position in the virtual game space. In step S 12, the operation data output from the controller 20 is stored in the operation data buffer 62. In step S14, the position of each object in the virtual game space is updated based on the object movement control program 50 of FIG. In particular, if the character object CH1 is set as a player character that moves based on the operation of the player's controller 20, the position is updated based on the operation data stored in the operation data buffer 62 in step S12. Of course, the character object CH1 may be set as a non-player character that attacks the player character, for example. At this time, the position of the character object CH1 is updated based on the program stored in advance according to the position of the player character.

  In step S16, a mask generation process is performed based on the mask generation program of FIG. Details of this mask generation processing will be described later. In step S18, drawing processing is performed based on the drawing program 58 of FIG. 3, and as a result, the game image to be displayed on the monitor 12 is stored in the color buffer 64. Details of this drawing processing will also be described later. In step S20, a video signal based on the game image stored in the color buffer 64 is output to the monitor 12 based on the display control program 60 of FIG. 3, and as a result, an image is displayed on the screen of the monitor 12 as a game image. Is done. In step S22, it is determined whether or not the game is over. If the game is continuing, the process returns to step S12. While the game continues, the processing from step S12 to step S18 is repeated at a period of 1/30 second, for example.

  Next, details of the mask generation processing will be described with reference to the flowchart of FIG. Here, description will be made assuming that the viewpoint and each object (character object CH1 and field objects OB1 to OB3) are arranged in the virtual game space as shown in FIG. FIG. 10 shows a state in which the virtual game space is viewed from the direction perpendicular to the line-of-sight direction. In FIG. 10, an object included in a space (view volume) between the near clip plane and the far clip plane is a drawing target. In addition, although the example of drawing an object by perspective projection is shown in the example of FIG. 10, the present invention is not limited to this, and the object may be drawn by parallel projection. As shown in FIG. 6, it is assumed that the transparency flag 84 of the field object OB1 is 1, and the transparency flag 84 of the field object OB2 and the field object OB3 is set to 0.

  When the mask generation process is started, first, in step S24, each character object (character object CH1 in the example of FIG. 5) is projected on the screen plane set in the virtual game space based on the projection program 56 of FIG. The Specifically, the coordinates on the display screen of the monitor 12 corresponding to each character object are obtained by performing perspective projection conversion of the arrangement coordinates (three-dimensional coordinates) of each character object in the three-dimensional virtual game space based on the viewpoint. (Two-dimensional coordinates) is calculated. In the example of FIG. 10, the near clip surface is set as the screen plane, but the present invention is not limited to this. This projection process is typically performed by coordinate-converting the vertex coordinates of the polygons constituting each character object using a predetermined conversion matrix. FIG. 11 shows the result of projecting the character object CH1 on the screen plane. Here, an example in which the polygon constituting the character object CH1 is projected onto the screen plane has been shown, but the present invention is not limited to this, and only the point indicating the position of the character object CH1 may be projected onto the screen plane. .

  In step S26, monochrome image data as shown in FIG. 12 is generated based on the position of each character object projected on the screen plane. Specifically, an image showing a circular area (mask area) as shown in FIG. 12 centering on the position of each character object projected on the screen plane is drawn. The color buffer 64 may be temporarily used for drawing the mask area.

  In step S28, the image data obtained in step S26 is stored in the main memory 28 as mask data. At this time, the resolution of the image data stored as the mask data is not necessarily the same as the resolution of the game image, and may be stored in the main memory 28 after the resolution is lowered than the game image. Thereby, the storage area of the main memory 28 required for storing mask data can be saved. When the mask data with the reduced resolution is used in the drawing process described later, the resolution of the mask data stored in the main memory 28 may be converted to the resolution of the game image.

  Next, details of the drawing process will be described with reference to the flowchart of FIG.

  When the drawing process starts, first, in step S30, a drawing target object to be drawn in the color buffer is determined. Although the drawing order of the objects is arbitrary, if necessary, the drawing order of the objects may be determined in advance, and the objects may be drawn according to the determined order. For example, if an opaque object is drawn and then a semi-transparent object is drawn, transparency processing (alpha composition) becomes relatively easy. Also, for example, if an object far from the viewpoint is drawn first, and then an object close to the viewpoint is drawn, the hidden surface can be deleted without performing the Z test using the Z buffer.

  In step S32, it is determined whether or not the drawing target object determined in step S30 is a character object. If it is a character object, the process proceeds to step S38. If it is not a character object (that is, a field object), the process proceeds to step S34.

  In step S34, with reference to the main memory 28, it is determined whether or not the transparency flag 84 of the field object to be rendered is 0. If the transmission flag 84 is 0, the process proceeds to step S38, and if the transmission flag 84 is not 0 (that is, 1), the process proceeds to step S36.

  In step S36, the drawing target object (here, the field object whose transparency flag is 1) is drawn using the mask data 86 stored in the main memory 28 by the mask generation process described above. Further, the transmittance of each pixel of the drawing target object is determined according to the value of each pixel of the mask image (mask region image) included in the mask data 86 for one screen. Specifically, when a drawing target object arranged in a three-dimensional virtual game space is subjected to perspective projection conversion and drawn in the color buffer 64, the mask area 86 is referred to by referring to the mask data 86 stored in the main memory 28. The transmittance of the object to be drawn in the overlapping portion is changed to 100% (that is, the portion corresponding to the mask area is not drawn in the color buffer 64), and the transmittance of other portions is not changed (that is, normal display). The drawing target object is drawn. For example, when the field object OB1 is drawn using the mask data of FIG. 12, the drawing result is as shown in FIG.

  In step S38, the drawing target object (in this case, the character object or the field object whose transparency flag is 0) is normally set, that is, without referring to the mask data 86 stored in the main memory 28 by the mask generation process described above. Drawn.

  In step S40, it is determined whether or not drawing has been completed (that is, whether or not drawing of all objects included in the view volume has been completed). If the drawing has not been completed, the process returns to step S30 to determine and draw the next drawing target object. When the drawing is completed, the process proceeds to step S20 in FIG. 7, and as a result, for example, a game image as shown in FIG. 6 is displayed on the monitor 12.

  In the present embodiment, the portion corresponding to the mask area of the drawing target object is not drawn, but the present invention is not limited to this. For example, a portion corresponding to the mask area in the drawing target object may be displayed semi-transparently. In this case, the alpha value (the value that determines the transmittance) of the drawing target object corresponding to the mask area may be changed to an appropriate value, and alpha composition based on the changed alpha value may be performed.

  In the present embodiment, binary image data as shown in FIG. 12 is used as mask data. However, the present invention is not limited to this, and image data having a larger number of gradations may be used. FIG. 14 shows an example in the case where image data having four values according to the transmittance is used as mask data. In particular, the mask data in FIG. 14 is mask data that gradually changes the transmittance of the object at the boundary of the mask region. FIG. 15 shows the result of drawing the field object OB1 using this mask data. The transmittance (alpha value) of the field object OB1 is changed according to the value of the mask data, and a game image as shown in FIG. 16 is generated by alpha composition based on the changed alpha value. In the example of FIG. 16, the transmissivity of the portion corresponding to the boundary portion of the mask area in the field object OB1 is gradually changed, so that luxury and beauty can be added as an image expression compared to the example of FIG. .

  In the present embodiment, the mask region is circular. However, the present invention is not limited to this, and the mask region may have any shape (for example, an ellipse, a rectangle, or a star).

  Note that the size of the mask area may be fixed, or may vary according to the size and state of the character object. The size of the mask area may be changed according to the distance from the viewpoint to the character object. In particular, when a game image is generated by perspective projection, for example, when the character object moves in the direction of the arrow in FIG. 17A, the mask area increases as the character object moves away from the viewpoint as shown in FIGS. 17B and 17C. It is preferable to reduce the size of. As a result, a game image with more elaborate image representation can be obtained while always displaying the character object.

  In the example of FIG. 11, there is only one character object projected on the screen plane. Therefore, in FIG. 12, there is only one mask area. However, when there are a plurality of character objects as shown in FIG. As shown in FIG. 19, the mask data is provided with a plurality of mask areas respectively corresponding to the plurality of character objects (here, character objects CH1 and CH2). A game image as shown in FIG. 20 is obtained by drawing a field object (here, field object OB1) having a transparency flag of 1 using the mask data of FIG.

  In this embodiment, the transparency flag 84 of the field object OB1 in FIG. 10 is set to 1, and the transparency flag 84 of the field object OB2 and the field object OB3 is set to 0. However, the value of the transparency flag of the field object Is set appropriately in advance in consideration of the position of the field object and the setting of the viewpoint. For example, for a field object representing the ground, the transparency flag is set to 0 because the character object is not normally hidden behind the ground. On the other hand, for a field object that represents a position higher than the character object, such as a sail of a ship, the transparency flag tends to be hidden when the viewpoint is set above the character object. Set to 1. For a field object that is smaller than the character object or a semi-transparent field object, the transparency flag may be set to 0 because the display of the character object is not greatly prevented.

  Note that if it is allowed to have a game image with a sense of incongruity, transparency processing using mask data may be applied to all field objects without setting a transparency flag. Absent. As a result, at least the character object is necessarily displayed.

  As described above, according to the first embodiment, mask data is generated based on the position of the character object, and the field object is subjected to transparency processing using the mask data, so that the character object can be always displayed. it can.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.

  First, consider a case where a plurality of objects (character objects CH1 to CH3 and field objects OB1 and OB2) are arranged in a three-dimensional virtual game space as shown in FIG. It is assumed that the transparency flag is set to 1 for the field object OB1, and the transparency flag is set to 0 for the field object OB2. Here, when the scene viewed from the viewpoint A in FIG. 21 is drawn using the method of the first embodiment, a game image as shown in FIG. 22 is obtained. In the game image of FIG. 22, each character object CH1 to CH3 is appropriately displayed. However, when the scene viewed from the viewpoint B in FIG. 21 is drawn using the method of the first embodiment, the character objects CH1 and CH2 are not displayed as shown in FIG. Further, a part of the field object OB1 is missing due to the influence of the mask area corresponding to the character object CH1, so that the game image has a sense of incongruity. In the second embodiment, such a problem can be solved.

  In the second embodiment, the transmission process using the mask data is applied only to the field object closer to the viewpoint than the reference position determined in advance. The reference position may be defined by an absolute position in the virtual game space, may be defined by a relative position based on the viewpoint, or may be defined as a position of a specific character object.

  For example, a case will be described in which a plurality of objects (character objects CH1 to CH3 and field objects OB1 and OB2) are arranged in the virtual game space as shown in FIG. 24 and the reference position is set to the position shown in the figure.

  When the scene viewed from the viewpoint A in FIG. 24 is drawn, mask data is generated based on the positions of the character objects CH1 to CH3. The field object OB2 farther from the viewpoint than the reference position is normally drawn. As a result, a game image as shown in FIG. 25 is obtained.

  On the other hand, when the scene viewed from the viewpoint B in FIG. 24 is drawn, mask data is generated based on the positions of the character objects CH1 to CH3, and the field object OB2 closer to the viewpoint (here, the viewpoint B) than the reference position. Transmission processing using mask data is performed, and the field object OB1 farther from the viewpoint than the reference position is normally drawn. As a result, a game image as shown in FIG. 26 is obtained.

  Here, in both the game image of FIG. 25 and the game image of FIG. 26, all the character objects CH1 to CH3 are displayed, and the field object located farther from the viewpoint than the character object is unnaturally missing. There is no end to it.

  Hereinafter, the detailed operation of the second embodiment will be described focusing on the differences from the first embodiment.

  In the second embodiment, the reference position 88 is stored in the main memory 28 as shown in FIG. Here, it is assumed that the reference position is defined by the distance from the viewpoint.

  The drawing process of the second embodiment will be described below with reference to the flowchart of FIG. Note that the flowchart of FIG. 28 shows only a part of the drawing process, and the flowchart of FIG. 9 is used for the remaining steps. In the flowchart of FIG. 28, the same steps as those in the flowchart of FIG. 9 are denoted by the same reference numerals.

  When the drawing target object is determined in step S30 in FIG. 9, it is determined in step S32 in FIG. 28 whether the drawing target object is a character object. If it is a character object, the process proceeds to step S38. If it is not a character object (that is, a field object), the process proceeds to step S42.

  In step S <b> 42, it is determined with reference to the main memory 28 whether the field object to be drawn is closer to the viewpoint than the reference position 88. If the field object to be drawn is closer to the viewpoint than the reference position 88, the process proceeds to step S38. If the field object is farther from the viewpoint than the reference position 88, the process proceeds to step S36.

  In step S36, a drawing target object (here, a field object closer to the viewpoint than the reference position 88) is drawn using the mask data 86 stored in the main memory 28 by the mask generation process.

  In step S38, a drawing target object (here, a character object or a field object farther from the viewpoint than the reference position 88) is drawn normally.

  As a result of the drawing process as described above, a game image as shown in FIG. 25 or 26 is generated.

  In the present embodiment, the reference position is defined by the distance from the viewpoint, but the present invention is not limited to this. For example, as described above, the position of a specific character object may be set as the reference position. In this case, it is necessary to update the reference position 88 stored in the main memory 28 according to the movement of the specific character object.

  As shown in FIG. 29, when there are a plurality of character objects (here, character objects CH1 to CH4) in the virtual game space, the character objects (here, character objects CH1 to CH3) included in the visual volume. It is preferable to set the position of the character object (here, the character object CH3) farthest from the viewpoint as the reference position. As a result, all the character objects included in the view volume are displayed, and a game image with a little uncomfortable feeling (a part of the field object OB3 is not lost in the example of FIG. 29) can be obtained. become. In order to realize this, steps S44 to S46 of FIG. 30 may be executed before the drawing process of step S18 of FIG. Specifically, in step S44, the position of the character object farthest from the viewpoint among the character objects included in the visual volume is acquired. In step S46, the position of the character object acquired in step S44 (which may be an absolute position in the virtual space or a relative position based on the viewpoint) is stored in the main memory 28 as a reference position 88. To do.

  It is also possible to combine the technique of the first embodiment and the technique of the second embodiment. That is, the transparency process using the mask data is applied only to a field object that is closer to the viewpoint than the reference position and has a transparency flag of 1, and the transparency process is not applied to other field objects. May be.

(Third embodiment)
Next, a third embodiment of the present invention will be described.

  First, consider a case where a plurality of objects (character objects CH1 to CH3 and field objects OB1 and OB2) are arranged in a three-dimensional virtual game space as shown in FIG. In this case, regardless of the method of the first embodiment or the method of the second embodiment, the character object CH3 is displayed and falls behind the character objects CH1 and CH2 in the field object OB2. It is impossible to obtain a game image in which a portion is not unnecessarily lost. In the third embodiment, such a problem can be solved.

  In the third embodiment, mask data in which depth information is further added to the mask data as shown in FIGS. 12, 14, and 19 is generated, and the transmission processing is performed using the generated mask data. Is called.

  FIG. 32 is a diagram illustrating the principle of the third embodiment. By adding depth information corresponding to the position of the character object to each mask area of the mask data as shown in FIG. 12, FIG. 14 or FIG. 19, each character object (here, character A mask space extending from the position of the objects CH1 to CH3) toward the viewpoint can be defined. As shown in FIG. 33, the mask space is a space extending from the position of the character object toward the viewpoint in the virtual game space, and its shape is basically a conical shape when the object is drawn by perspective projection. When an object is drawn by parallel projection, it basically has a cylindrical shape. In the drawing process, based on the mask data, the field object is displayed transparent (or semi-transparent) in the mask space as shown in FIG. 33, and the field object is normally displayed in the other space.

  FIG. 34 shows an example of mask data generated in the third embodiment. In the mask generation process according to the third embodiment, a mask area is drawn based on the position of each character object projected onto the screen plane as in the first embodiment. It is determined in accordance with the depth (that is, the distance from the viewpoint to the corresponding character object). In the example of FIG. 34, the darkness of the color of the mask region increases as the depth of the mask space increases. The number of steps of the darkness level of the mask area is arbitrary. Note that the color density of the mask area in the mask data of FIGS. 12 and 14 represents the transmittance, whereas the color density of the mask area in the mask data of FIG. 34 represents the depth of the mask space. Represents. Also, by changing the size of the mask area in the mask data of FIG. 34 at the same time, it is possible to express an image according to FIGS. 17B and 17C. That is, the mask area is drawn smaller as the depth of the mask space increases. By doing so, more advanced image representation is possible. In particular, when it is necessary to distinguish between them, the mask data defining the transmittance as shown in FIGS. 12 and 14 is referred to as color mask data, and the mask defining the depth of the mask space as shown in FIG. The data is referred to as depth mask data.

  In the drawing process, the field objects OB1 and OB2 are drawn using mask data as shown in FIG. Specifically, in each of the field objects OB1 and OB2, the portion that intersects one of the mask spaces has a transmittance of 100% (that is, the portion that intersects the mask space is not drawn in the color buffer 64), and the other portions Each of the field objects OB1 and OB2 is drawn so that the transmittance of the image becomes 0% (that is, normal display). As a result, a game image as shown in FIG. 35 is obtained. In the game image of FIG. 35, the character object CH3 is displayed, and portions of the field objects OB1 and OB2 that are behind the character objects CH1 and CH2 are not unnecessarily lacking.

  Details of the mask generation processing in the third embodiment will be described below with reference to the flowchart of FIG.

  In step S24, as in the first and second embodiments, each character object is projected on the screen plane. In step S48, the position of each mask area is determined based on the position of each character object on the screen plane. In step S50, the color density of each mask area in the mask data is determined according to the distance from the viewpoint to each corresponding character object. In step S52, a mask area is drawn based on the determination results in steps S48 and S50. In step S54, the image data obtained in step S52 is stored in the main memory 28 as mask data.

  Next, details of the drawing process in the third embodiment will be described with reference to the flowchart of FIG. 37 differs from FIG. 9 only in that step S34 is not provided and step S36 is changed to step S56. Therefore, description of steps other than step S56 is omitted here.

  In step S32, it is determined whether the drawing target object is a character object. If it is not a character object (that is, a field object), the process proceeds to step S56. In step S56, the drawing target object (here, the field object) is drawn using the mask data 86 stored in the main memory 28 by the mask generation process. Specifically, of the drawing target object, a portion that hits the mask area when the drawing target object is projected onto the screen plane and that is smaller in distance from the viewpoint than the depth of the mask space indicated by the mask data The drawing target object is drawn so that the transmittance is 100% (that is, not drawn in the color buffer 64) and the transmittance is 0% (that is, normal display) for the other portions.

  In the present embodiment, the field object is drawn using only the depth mask data. However, by using the color mask data in addition to the depth mask data, as shown in FIG. It is also possible to gradually change the transmittance of the portion that hits the boundary. Specifically, in the mask generation process, in addition to the depth mask data of FIG. 34, for example, color mask data as shown in FIG. 38 is generated, and these two mask data are stored in the main memory 28. Then, in the drawing process, based on the depth mask data, the part included in the mask space of the drawing target object is distinguished from the other part, and the part included in the mask space is transmitted through that part according to the color mask data. What is necessary is just to change a rate (alpha value).

  In this embodiment, as shown in FIG. 34, in the depth mask data, the darkness of the color of each mask area is made uniform, but the present invention is not limited to this. For example, when character objects CH1 and CH2 and field objects OB1 and OB2 are arranged in the virtual game space as shown in FIG. 39, it is possible to generate depth mask data as shown in FIG. In FIG. 40, each mask region is drawn so that the color becomes lighter as the distance from each center increases. When the field objects OB1 and OB2 in FIG. 39 are drawn using such depth mask data, a game image as shown in FIG. 41 is obtained. From the game image of FIG. 35, the user cannot determine whether the character object CH3 is positioned in front of or behind the field object OB2. However, according to the game image of FIG. The user can clearly grasp that the field object OB2 is located behind the field object OB2.

1 is an external view of a game system according to an embodiment of the present invention. Internal configuration diagram of game console Part of the memory map of the main memory 28 Part of the memory map of the main memory 28 Game image example according to the first embodiment Game image example according to the first embodiment Flow chart showing the flow of main processing Flow chart showing the flow of mask generation processing Flow chart showing the flow of drawing processing Example of object placement in virtual game space The figure which shows the character object projected on the screen plane in mask data generation processing Example of mask data generated in mask data generation processing The figure which shows the result of drawing a field object using mask data Example of mask data generated in mask data generation processing The figure which shows the result of drawing a field object using mask data Game image example according to the first embodiment Game image example according to the first embodiment Game image example according to the first embodiment Game image example according to the first embodiment Game image example according to the first embodiment Example of mask data generated in mask data generation processing Example game image when multiple character objects are displayed Example of object placement in virtual game space Game image example Game image example Example of object placement in virtual game space Game image example according to the second embodiment Game image example according to the second embodiment Part of the memory map of the main memory 28 according to the second embodiment The flowchart which shows the flow of the drawing process which concerns on 2nd Embodiment. Diagram showing an example of setting the reference position The flowchart which shows the flow of the main process which concerns on the modification of 2nd Embodiment. Example of object placement in virtual game space The figure which shows the principle of 3rd Embodiment Diagram for explaining the mask space Example of depth mask data generated in the third embodiment Game image example according to the third embodiment The flowchart which shows the flow of the mask production | generation process which concerns on 3rd Embodiment. The flowchart which shows the flow of the drawing process which concerns on 3rd Embodiment. Example of color mask data generated in the third embodiment Example of object placement in virtual game space Example of depth mask data generated in the third embodiment Game image example according to the third embodiment Game image example according to the prior art Game image example according to the prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Game system 12 Monitor 14 Game machine main body 16 Optical disk 18 Memory card 20 Controller 22 Speaker 24 CPU
26 GPU
28 Main memory 30 DSP
32 ARAM
34 Memory controller 36 Controller I / F
38 Video I / F
40 External memory I / F
42 Audio I / F
44 Disc I / F
46 disk drives

Claims (2)

A game image for displaying one or more first objects and one or more second objects in a three-dimensional virtual game space on a display screen by performing perspective projection conversion based on a viewpoint set in the virtual game space. Is an image processing program for causing a computer of a game device to execute a process of drawing in a drawing buffer area,
In the computer,
An arrangement position determining step for determining a first three-dimensional coordinate for arranging the first object and a second three-dimensional arrangement coordinate for arranging the second object in the three-dimensional virtual game space;
A calculation step of calculating two-dimensional coordinates on the display screen by performing perspective projection conversion of the first three-dimensional arrangement coordinates based on the viewpoint;
A mask data generation step of generating mask data for one screen in which a mask image of a predetermined shape is drawn at a position in the drawing buffer area corresponding to the two-dimensional coordinates on the display screen;
Drawing the first object in the drawing buffer area without referring to the mask data when the first object placed at the first three-dimensional coordinates is perspective-projected and drawn in the drawing buffer area A first object drawing step, and when the second object arranged at the second three-dimensional coordinates is perspective-projected and drawn in the drawing buffer area, by referring to the mask data, A second object drawing step of drawing the second object by changing the transmittance of the second object in the overlapping portion as compared with the portion not overlapping the mask image;
An image processing program for executing The mask image is an image in which the color density becomes lighter or darker from the center toward the periphery,
The second object drawing step draws the second object so that the transmittance of the second object changes according to the color density of the mask image in a portion where the mask image and the second object overlap. The image processing program according to claim 1.

Images