JP4592043B2 - Image generation system, program, and information storage medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image generation system, a program, and an information storage medium.
[0002]
[Background Art and Problems to be Solved by the Invention]
Conventionally, an image generation system (game system) that generates an image that can be seen from a virtual camera (a given viewpoint) in an object space that is a virtual three-dimensional space is known. Popular. Taking an image generation system capable of enjoying a role-playing game (RPG) as an example, a player operates a character (object), which is his or her own character, and moves it on a map in the object space to play against an enemy character. Play games, interact with other characters, and visit various towns.
[0003]
Now, in such an image generation system, it is an important issue to generate a more realistic image in order to improve the player's virtual reality. Therefore, it is desirable that an irregular display object such as a flame or smoke generated during the game can be expressed with a realistic image.
[0004]
As a technique for expressing such an irregular display object such as a flame, the following techniques can be considered.
[0005]
In the first method, a flame is expressed using a flame polygon to which a texture of a flame picture is mapped.
[0006]
However, in this first method, when the flame polygon is viewed from various directions, the player is informed that the shape of the flame polygon is planar, and the virtual reality of the player is reduced.
[0007]
In the second method, a so-called particle system is used. That is, an irregularly shaped flame is represented by a set of flame particles that have attribute information such as position and color and that are generated, moved, and disappear according to a given rule.
[0008]
However, such a particle system has a drawback that the processing load of the image generation system becomes very heavy.
[0009]
The present invention has been made in view of the above problems, and an object thereof is to provide an image generation system, a program, and an information storage medium that can generate a realistic image of a display object with a small processing load. There is.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides an image generation system for generating an image, wherein an object including first to Nth primitive surfaces is set in an object space, and the object includes the first Means for determining a drawing order for the first to Nth primitive surfaces according to a relative direction relationship between at least one of the first to Nth primitive surfaces and the orientation of the virtual camera; And means for drawing the first to Nth primitive surfaces in the determined drawing order. The program according to the present invention is a program usable by a computer (a program embodied in an information storage medium or a carrier wave), and causes the computer to realize the above means (makes the computer function as the above means). And An information storage medium according to the present invention is an information storage medium readable (usable) by a computer, and includes a program for causing the computer to realize the above means (functioning the computer as the above means). And
[0011]
According to the present invention, an object including the first to Nth primitive surfaces is set (arranged) in the object space, and an image that can be seen from the virtual camera is generated in the object space.
[0012]
According to the present invention, the drawing order (sort order) for the first to Nth primitive planes according to the relative directional relationship (angle or inner product value, etc.) between the primitive plane of the object and the orientation of the virtual camera. Are determined, and the first to Nth primitive surfaces are drawn in the determined drawing order.
[0013]
As described above, according to the present invention, the drawing order of primitive surfaces can be determined only by determining the relative directional relationship between the primitive surfaces and the orientation of the virtual camera. Therefore, it is possible to determine the drawing order of the primitive plane with a much smaller processing load than the method of determining the drawing order based on the depth value or the like.
[0014]
The image generation system, program, and information storage medium according to the present invention are characterized in that the first to Nth primitive surfaces are drawn in the drawing order while being α-combined.
[0015]
In this way, it is possible to realize an α composition process with no contradiction of primitive surfaces.
[0016]
The α value set for the primitive surface may also be determined according to the relative direction relationship between the primitive surface and the orientation of the virtual camera.
[0017]
In the image generation system, the program, and the information storage medium according to the present invention, the object includes a J-th primitive surface intersecting the first to N-th primitive surfaces, and the J-th primitive surface is drawn first. Then, the first to Nth primitive surfaces are drawn.
[0018]
In this way, it is not necessary to determine the drawing order for the Jth primitive surface, and the processing load can be reduced.
[0019]
In this case, an object having a configuration in which a plurality of first to Nth primitive surfaces are arranged radially from a reference line may be employed. Further, the Jth primitive surface may intersect so as to be in contact with the end sides of the first to Nth primitive surfaces, or may intersect between the upper end side and the lower end side of the first to Nth primitive surfaces. You may do it.
[0020]
In the image generation system, the program, and the information storage medium according to the present invention, the first to Nth primitive surfaces are radially arranged from a reference line, and are divided by the first to Nth primitive surfaces. In the Mth particle area, a plurality of particle primitives that disappear at a given lifetime are generated.
[0021]
In this way, it is possible to express a display object that is more voluminous and looks three-dimensional than in the case where an object is simply composed of primitive surfaces.
[0022]
The present invention is also an image generation system for generating an image, and performs a process of generating a plurality of particle primitives that disappear at a given lifetime in each particle area of the first to Mth particle areas. Means for determining the drawing order for the first to M-th particle areas, and means for drawing the particle primitives generated in the particle area in order from the particle area having the highest drawing order priority. It is characterized by including. The program according to the present invention is a program usable by a computer (a program embodied in an information storage medium or a carrier wave), and causes the computer to realize the above means (makes the computer function as the above means). And
An information storage medium according to the present invention is an information storage medium readable (usable) by a computer, and includes a program for causing the computer to realize the above means (functioning the computer as the above means). And
[0023]
According to the present invention, for example, when the priority of the drawing order of the first particle area is the highest, drawing is first performed for the particle primitive generated in the first particle area. After that, drawing is performed on the particle primitive generated in the particle area having the next highest priority in the drawing order.
[0024]
In this way, it is possible to remarkably reduce the load of the drawing order determination process, compared to the technique of sorting and drawing all the particle primitives at once.
[0025]
An image generation system, a program, and an information storage medium according to the present invention include at least one primitive surface among the first to Nth primitive surfaces that divide the first to Mth particle areas and the orientation of the virtual camera. The drawing order for the first to M-th particle areas or the drawing for the first to M-th particle areas and the first to N-th primitive planes according to the relative directional relationship The order is determined.
[0026]
In this way, the drawing order for the particle area and the primitive surface can be determined only by determining the relative direction relationship between the primitive surface and the orientation of the virtual camera. Therefore, the drawing order of the particle area and the primitive surface can be determined with a much smaller processing load than the method of determining the drawing order based on the depth value or the like.
[0027]
The image generation system, the program, and the information storage medium according to the present invention may be configured such that a particle primitive generated in an Lth (1 ≦ L ≦ M) particle area in the first to Mth particle areas is The movement is limited so as to move within the Lth particle area.
[0028]
In this way, it is possible to prevent the particle primitive generated in the Lth particle area from entering another particle area, and the problem that the particle primitive is drawn in the wrong drawing order. Can be prevented.
[0029]
The image generation system, the program, and the information storage medium according to the present invention are characterized in that the movement of the particle primitive is limited by controlling at least one of the initial speed and the life of the particle primitive.
[0030]
In this way, it is possible to limit the movement of particle primitives with a low-load process that only limits the initial speed and lifetime.
[0031]
In the present invention, an object including the first to N-th primitive planes is set in the object space, and at least one of the first to N-th primitive planes included in the object and the orientation of the virtual camera The drawing order of the first to Nth primitive faces may be determined according to the relative directional relationship, and the first to Nth primitive faces may be drawn in the determined drawing order. .
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present embodiment will be described with reference to the drawings.
[0033]
In addition, this embodiment demonstrated below does not limit the content of this invention described in the claim at all. Further, not all of the configurations described in the present embodiment are essential as a solution means of the present invention.
[0034]
1. Constitution
FIG. 1 shows an example of a functional block diagram of the image generation system (game system) of the present embodiment. In this figure, the present embodiment only needs to include at least the processing unit 100 (or include the processing unit 100 and the storage unit 170), and the other blocks can be optional components.
[0035]
The operation unit 160 is for a player to input operation data, and the function can be realized by hardware such as a lever, a button, a microphone, or a housing.
[0036]
The storage unit 170 serves as a work area such as the processing unit 100 or the communication unit 196, and its function can be realized by hardware such as a RAM.
[0037]
The information storage medium 180 (computer-readable medium) stores programs, data, and the like, and functions as an optical disk (CD, DVD), magneto-optical disk (MO), magnetic disk, hard disk, and magnetic tape. Alternatively, it can be realized by hardware such as a memory (ROM). The processing unit 100 performs various processes of the present invention (this 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 implement (execute, function) the means of the present invention (this embodiment) (particularly, the blocks included in the processing unit 100). Or a plurality of modules (including objects in object orientation) are included.
[0038]
Part or all of the information stored in the information storage medium 180 is transferred to the storage unit 170 when the system is powered on. The information storage medium 180 also includes a program for performing the processing of the present invention, image data, sound data, shape data of the display object, information for instructing the processing of the present invention, or processing in accordance with the instructions. Information etc. can be included.
[0039]
The display unit 190 outputs an image generated according to the present embodiment, and the function thereof can be realized by hardware such as a CRT, LCD, or HMD (head mounted display).
[0040]
The sound output unit 192 outputs the sound generated by the present embodiment, and its function can be realized by hardware such as a speaker.
[0041]
The portable information storage device 194 stores player personal data, game save data, and the like. As the portable information storage device 194, a memory card, a portable game device, and the like can be considered.
[0042]
The communication unit 196 performs various controls for communicating with the outside (for example, a host device or other image generation system), and functions as hardware such as various processors or a communication ASIC. Or by a program.
[0043]
Note that a program (data) for realizing (executing and functioning) each unit of the present invention (this embodiment) is transmitted from the information storage medium of the host device (server) via the network and the communication unit 196. You may make it deliver to. Use of such an information storage medium of the host device (server) is also included in the scope of the present invention.
[0044]
The processing unit 100 (processor) performs various processing such as game processing, image generation processing, or sound generation processing based on operation data, a program, and the like from the operation unit 160. In this case, the processing unit 100 performs various processes using the main storage unit 172 in the storage unit 170 as a work area.
[0045]
Here, the processing performed by the processing unit 100 includes coin (price) acceptance processing, various mode setting processing, game progress processing, selection screen setting processing, and the position and rotation angle of an object (one or a plurality of primitives). Processing for obtaining (rotation angle around X, Y or Z axis), processing for moving an object (motion processing), processing for obtaining a viewpoint position (virtual camera position) and line of sight angle (virtual camera rotation angle), map object Consider processing such as placing objects in the object space, hit check processing, computing game results (results, results), processing for multiple players to play in a common game space, or game over processing, etc. Can do.
[0046]
The processing unit 100 includes an object space setting unit 110, an α value setting unit 112, a particle processing unit 114, a drawing order determination unit 116 (sorting unit), and a drawing unit 120. Note that it is not necessary for the processing unit 100 to include all of these functional blocks 110 to 120, and some of the functional blocks may be omitted.
[0047]
Here, the object space setting unit 110 performs a process for setting (arranging) various objects such as maps (objects composed of primitive surfaces such as polygons, free-form surfaces or subdivision surfaces) in the object space. More specifically, the position and rotation angle (direction) of the object in the world coordinate system are determined, and the rotation angle (rotation around the X, Y, and Z axes) is determined at that position (X, Y, Z). Place the object.
[0048]
The object space setting unit 110 according to the present embodiment includes an object (an object including a plurality of intersecting primitive surfaces) including a plurality of primitive surfaces (polygon, free-form surface, subdivision surface, etc.) radially arranged from the reference line. ) Is set in the object space. In the present embodiment, by using an object having such a shape, a realistic expression of an irregular display object such as a flame or smoke has been successfully achieved.
[0049]
Note that this object may include a primitive surface (base primitive surface; J-th primitive surface in a broad sense; the same applies to the following description) that intersects a plurality of primitive surfaces arranged radially. By providing such a primitive surface, an image occupying a certain area can be displayed even when the object is viewed from above, and the realism of the generated image can be increased.
[0050]
The α value setting unit 112 is a relative direction relationship between one or a plurality of primitive planes included in an object and a virtual camera direction (for example, a line-of-sight direction) (a relative relationship between a primitive plane direction and a virtual camera direction). The α value of the primitive surface is set according to the angle formed by these orientations, the inner product value obtained from these orientations, and the relationship determined by these angles, inner product values and mathematically equivalent parameters, etc. To do.
[0051]
More specifically, for example, a vector representing the orientation of the virtual camera (a three-dimensional vector representing the orientation or a two-dimensional vector obtained by projecting this three-dimensional vector onto a given plane), and the orientation of the primitive surface An angle (the inner product value of these vectors) formed with a vector (a vector in a direction along the primitive surface, a vector orthogonal to the primitive surface, a three-dimensional vector, or a two-dimensional vector) The α value is obtained on the basis of (1), and this α value is given to the primitive surface itself as the representative α value, or is given to the vertex of the primitive surface as the vertex α value.
[0052]
In this case, in this embodiment, as the primitive plane of the object (vector parallel to the primitive plane) and the direction of the virtual camera (gaze direction) become parallel, an α value that makes the primitive plane more transparent is obtained. Set to the primitive surface. In other words, an α value is set for the primitive surface such that the primitive surface becomes more opaque as the object's primitive surface and the orientation of the virtual camera are orthogonal.
[0053]
The α value (A 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 mask information, translucency (equivalent to transparency and opacity), bump information, and the like.
[0054]
The particle processing unit 114 generates a particle primitive (for example, a flame particle or smoke particle primitive) for representing an irregular display object (for example, flame, smoke, water, explosion) whose shape is deformed over time. A process of sequentially generating, moving, or extinguishing is performed. More specifically, a process of randomly changing the generation amount, generation position, movement state (speed, acceleration, etc.) or lifetime of the particle primitive is performed. As a result, an irregular display such as a flame can be expressed realistically.
[0055]
The particle processing unit 114 of the present embodiment performs processing for generating a plurality of particle primitives that disappear at a given lifetime in each particle area of a plurality of particle areas (particle existence areas). In addition, processing is performed to limit the movement of these particle primitives so that they do not go outside the generated particle area.
[0056]
When an object is composed of a plurality of primitive surfaces arranged radially from the reference line, the particle area can be divided using these primitive surfaces.
[0057]
The particle primitive may be expressed by a primitive surface (sprite polygon) to which a texture of a picture such as flame or smoke is mapped, or may be expressed by a primitive point or a primitive line.
[0058]
The drawing order determination unit 116 determines the drawing order for the primitive plane of the object according to the relative direction relationship between one or more primitive planes included in the object and the orientation of the virtual camera. Then, the primitive planes are sorted in the determined drawing order. The drawing order determination unit 116 also determines the drawing order for the above-described particle area.
[0059]
In this case, when the relative directional relationship (inner product value) between the primitive surface and the orientation of the virtual camera is obtained by the α value setting unit 112, the obtained relative directional relationship (inner product value). It is desirable to determine the drawing order for the primitive surface and particle area based on By doing so, the processing load can be reduced.
[0060]
In addition, when there are a plurality of objects including a plurality of primitive surfaces arranged radially from the reference line, the drawing order determination unit 116 also determines the drawing order of the plurality of objects. More specifically, these objects are sorted by, for example, the Z sort method (sort by depth value).
[0061]
The drawing unit 120 performs an image drawing process based on the results of various processes performed by the processing unit 100. For example, when generating a so-called three-dimensional image, first, geometric processing such as coordinate conversion, clipping processing, perspective conversion, or light source calculation is performed, and based on the processing result, primitive surface data (primitive surface vertex) (Position coordinates, texture coordinates, color (luminance) data, normal vector, α value, etc.) are created. Based on this primitive surface data (data of primitive surfaces such as polygons, free-form surfaces or subdivision surfaces; drawing data), an image of the object (one or a plurality of primitive surfaces) after the geometry processing is drawn buffer 174 ( The image data is drawn in a pixel buffer such as a frame buffer or a work buffer. Thereby, an image that can be seen from the virtual camera (given viewpoint) in the object space is generated.
[0062]
The drawing unit 120 according to the present embodiment draws the primitive surface (primitive surface data) included in the object in the drawing order determined by the drawing order determination unit 116.
[0063]
In the rendering process in the rendering unit 120, pixels are obtained by a depth comparison method (for example, Z buffer method) using a depth buffer (for example, Z buffer or stencil buffer) in which depth information (for example, Z value) is stored. It is desirable to perform hidden surface removal in units.
[0064]
The drawing unit 120 includes a texture mapping unit 122 and an α synthesis unit 124.
[0065]
The texture mapping unit 122 performs processing for mapping the texture stored in the texture storage unit 176 to the object.
[0066]
Here, in the present embodiment, the texture storage unit 176 stores data of a compressed movie texture (compressed movie) including a series of first to Nth compressed textures (first to Nth compressed frame images).
[0067]
A decompression unit (not shown) performs decompression processing based on the compressed movie texture data, and the texture mapping unit 122 decompresses the series of first to Nth compressed textures. Processing for sequentially mapping the Nth expanded texture (first to Nth expanded frame images) to the object is performed.
[0068]
In this embodiment, when an object is composed of a plurality of primitive surfaces arranged radially from the reference line, a common texture is used for the plurality of primitive surfaces. For example, when data of a series of movie textures (for example, a movie texture representing a flame picture) is stored in the texture storage unit 176, this series of movie textures is applied to all primitive surfaces included in the object. Make mapping.
[0069]
Note that the unit for mapping the texture may be a single primitive surface or a plurality of primitive surfaces. Alternatively, a primitive surface obtained by further dividing one primitive surface may be used.
[0070]
The α synthesis unit 124 performs α synthesis processing (α blending, α addition, α subtraction, or the like) based on the α value (A value). For example, when the α synthesis is α blending, a synthesis process as shown in the following equation is performed.
[0071]
R _Q = (1-α) × R ₁ + Α × R ₂ (1)
G _Q = (1-α) × G ₁ + Α × G ₂ (2)
B _Q = (1-α) × B ₁ + Α × B ₂ (3)
Where R ₁ , G ₁ , B ₁ Are the R, G, B components of the color (luminance) of the image (background image) already drawn in the drawing buffer 174, and R ₂ , G ₂ , B ₂ Are the R, G, and B components of the color of the object (primitive) to be drawn in the drawing buffer. R _Q , G _Q , B _Q Are the R, G, B components of the color of the image obtained by α blending.
[0072]
In this embodiment, the α composition unit 124 performs α composition processing based on the α value set on the primitive surface by the α value setting unit 112.
[0073]
More specifically, the α value setting unit 112 sets a representative α value of the primitive surface for the primitive surface. Based on the representative α value, the α value of the vertex (composition point) of the object (primitive surface) is obtained. Then, an alpha value of each pixel (dot) of the object (object after perspective transformation) is obtained by the interpolation process based on the alpha value of the vertex, and an alpha synthesis process is performed based on the obtained alpha value of each pixel. Done.
[0074]
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 not only the single player mode but also a multiplayer mode in which a plurality of players can play. The system may also be provided.
[0075]
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 using a plurality of terminals (game machine, mobile phone).
[0076]
2. Features of this embodiment
Next, features of the present embodiment will be described with reference to the drawings.
[0077]
In the following, the case where the present embodiment is applied to the expression of flame will be mainly described as an example, but the present embodiment can also be applied to image expression other than the flame. In the present embodiment, the case where the primitive surface is a polygon will be mainly described as an example, but the primitive surface of the present embodiment is not limited to a polygon.
[0078]
2.1 Object structure
In the present embodiment, an object OB having a configuration as shown in FIG. 2 is used to represent an irregular display object such as a flame.
[0079]
This object OB includes polygons PL1, PL2, PL3, and PL4 (first to Nth primitive surfaces in a broad sense, which are radially arranged from a reference line RL (center line)). Also included are polygons PL0 (PL0-1 to PL0-4, which are intersected so as to be in contact with the end sides (lower end sides) of these polygons PL1 to PL4.
[0080]
3A to 3C show examples of textures (movie textures) used for texture mapping of the object OB. These textures are textures that express flames, and by continuously playing a movie of these series of textures, it is possible to realistically represent how the flames are burning while shaking.
[0081]
In the present embodiment, common textures shown in FIGS. 3A to 3C are used in texture mapping for the polygons PL0 (PL0-1 to PL0-4), PL1, PL2, PL3, and PL4. Specifically, the series of textures in FIGS. 3A to 3C are mapped to a pair of polygons PL1 and PL3. Similarly, these series of textures are mapped to polygon PL2 and PL4 pairs, PL0-1 and PL0-2 pairs, and PL0-3 and PL0-4 pairs, respectively.
[0082]
3A to 3C is a direction in which the direction of the arrow indicated by B1 in FIGS. 3A to 3C matches the direction of the arrows indicated by B2 to B9 in FIG. Mapping.
[0083]
In this way, even when the object OB is viewed from the virtual camera VC in various positions and directions as shown by C1 to C8 in FIG. 2, the flame images as shown in FIGS. Will always be visible.
[0084]
For example, when the object OB is viewed from the virtual camera VC at the position C1, images in which the textures of FIGS. 3A to 3C are mapped to the polygons PL2 and PL4 can be seen. When the object OB is viewed from the virtual camera VC at the position C3, images in which the textures of FIGS. 3A to 3C are mapped to the polygons PL1 and PL3 can be seen. When the object OB is viewed from the virtual camera VC at the position C5 (directly above), the textures shown in FIGS. 3A to 3C are displayed on the polygons PL0-1, PL0-2, PL0-3, and PL0-4. The image that is mapped becomes visible.
[0085]
In this way, it is possible to show the object OB as if it were a three-dimensional shape having a volume, despite the so-called split shape (cross shape). Accordingly, it becomes possible to realistically represent an indefinite display such as a flame with a small number of polygons, and a realistic image can be generated with a small processing load.
[0086]
The shape of the object OB is not limited to the shape shown in FIG.
[0087]
For example, as shown in FIGS. 4A and 4B (views of the object OB from above), polygons PL1 to 8 and PL1 to PL3 may be arranged radially from the reference line RL. That is, the number of polygons arranged radially and the manner of arrangement are arbitrary.
[0088]
Further, polygons other than the radially arranged polygons may be provided in the object. For example, in FIG. 2, PL0 is provided as such a polygon. In this case, in FIG. 2 and FIG. 4C (side view), the polygon PL0 that intersects with the edges of the polygons PL1 to PL4 is provided, but FIG. 4D (side view). As shown in FIG. 4, a polygon PL0 ′ that intersects between the upper and lower sides of the polygons PL1 to PL4 may be provided.
[0089]
2.2 Setting the α value
Now, when a flame image is generated using an object OB as shown in FIG. 2, it has been found that there are the following problems.
[0090]
For example, when the virtual camera VC is at a position as shown in FIG. 5A, an image as shown in FIG. 5B is generated. That is, an image on a line drawn with the color of the polygon PL1 is displayed between the images of the polygons PL2 and PL4.
[0091]
Further, when the virtual camera VC is at a position as shown in FIG. 5C, an image as shown in FIG. 5D is generated. That is, an image in which the polygons PL1 and PL2 and the polygons PL3 and PL4 are semitransparently synthesized with the same α value is generated. Therefore, there is a difference in color intensity between the area of the polygon PL2 and the area where the polygons PL1 and PL2 overlap, and between the area of the polygon PL4 and the area where the polygons PL3 and PL4 overlap. It will stand out.
[0092]
As a result, when an image is generated without any contrivance using the object OB having the shape shown in FIG. 2, polygon lines can be seen as the virtual camera VC moves around the object OB. There arises a problem that a difference between a dark portion and a light portion becomes conspicuous. For this reason, the player is informed that the object OB is not actually a three-dimensional object having a volume, but a split-shaped object as shown in FIG. 2, and the virtual reality of the player is reduced. End up.
[0093]
Therefore, in the present embodiment, the following method is adopted to solve such a problem.
[0094]
That is, in this embodiment, as shown in FIG. 6A, the angle θ (or cos θ) formed by the polygon PL1 (PL2 to PL4) of the object OB and the virtual camera VC. In a broad sense, a relative directional relationship. However, the α values of the polygons PL1 to PL4 are set in accordance with the same.
[0095]
For example, in FIG. 6B, the orientation of the virtual camera VC is parallel to the polygon PL1 (PL3) (orthogonal to PL2, 4), and θ is 0 degree. In this case, the α value of the polygon PL1 (PL3) is set to αMIN (minimum value, for example, 0.0), and PL1 appears to be more transparent. On the other hand, the α value of the polygons PL2 and PL4 is set to αMAX (maximum value, for example, 1.0), and PL2 and PL4 appear to be more opaque. By doing in this way, the color line of the polygon PL1 that was conspicuous in FIG. 5B becomes inconspicuous, and a more natural image can be generated.
[0096]
In FIG. 6C, the orientation of the virtual camera VC is the orientation between the polygons PL1 and PL4, and θ is, for example, 45 degrees. In this case, both the α value of the polygon PL1 (PL3) and the α value of PL4 (PL2) are set to, for example, an average value of αMIN and αMAX. Therefore, the difference between the dark portion and the light portion that are conspicuous in FIG. 5D becomes inconspicuous. As a result, it is possible to prevent a problem that the player is informed that the object OB has a split shape, and a more natural and realistic image can be generated.
[0097]
In FIG. 6D, the orientation of the virtual camera VC is parallel to the polygon PL4 (PL2) (orthogonal to PL1, 3), and θ is 90 degrees. In this case, the α value of the polygon PL4 (PL2) is set to αMIN, and PL4 appears to be more transparent. On the other hand, the α value of the polygons PL1 and PL3 is set to αMAX, and PL1 and PL3 appear to be more opaque. Thereby, it is possible to solve the problem that the color line of the polygon PL4 is conspicuously seen.
[0098]
Next, a specific method for setting the α value will be described in more detail with reference to the flowchart of FIG.
[0099]
First, vectors FL, FX, FY, and FZ are obtained (step S1).
[0100]
Here, as shown in FIG. 8, the vector FL is a unit vector that starts from the center point CP (representative point, the intersection of the reference line RL and the polygon PL0) of the object OB and faces the virtual camera VC.
[0101]
The vector FX is a unit vector (unit vector pointing in a direction along the plane of PL1, 3) that starts at the center point CP and is orthogonal to the polygons PL2, PL4.
[0102]
The vector FY is a unit vector that starts from the center point CP and is orthogonal to the polygon PL0.
[0103]
The vector FZ is a unit vector (unit vector pointing in a direction along the plane of PL2, 4) that starts from the center point CP and is orthogonal to the polygons PL1, PL3.
[0104]
In other words, these vectors FX, FY, and FZ are unit vectors in the X, Y, and Z axis directions in the local coordinate system of the object OB with the center point CP (representative point) as the origin.
[0105]
Next, the inner product value of these vectors FX, FY, FZ and FL is obtained as in the following equation (step S2).
[0106]
INR0 = FY · FL (4)
INR1 = FX ・ FL (5)
INR2 = FZ · FL (6)
These inner product values INR0 to INR3 are 0 when the two vectors are orthogonal, and 1 or -1 when they are parallel.
[0107]
Next, the representative α value of the polygon is obtained based on the obtained inner product values INR0 to INR2 (step S3). More specifically, first, conversion as shown in the following equation is performed.
[0108]
INRα0 = 1−ABS (INR0) (7)
INRα1 = 1−ABS (INR1) (8)
INRα2 = 1−ABS (INR2) (9)
Here, ABS (X) is a function that returns the absolute value of the argument X as a return value. By performing transformations such as the above equations (7), (8), and (9), INRα0, INRα1, and INRα2 are 1 when the two vectors are orthogonal, and 0 when they are parallel. Become.
[0109]
The representative α values αP0 to αP4 of the polygons P0 to P4 are obtained as follows using these INRα0 to INRα2.
[0110]
αP0 = (1-INRα0) × A0 + A1 (10)
αP1 = INRα1 × INRα0 × A0 + A1 (11)
αP2 = INRα2 × INRα0 × A0 + A1 (12)
αP3 = INRα1 × INRα0 × A0 + A1 (13)
αP4 = INRα2 × INRα0 × A0 + A1 (14)
Here, A0 = αMAX−αMIN and A1 = αMIN.
[0111]
For example, when the vector FL in FIG. 8 is parallel to FY (when FL is orthogonal to FX and FZ), INR0 = 1, INR1 = 0, and INR2 = 0 from the above equations (4) to (6). From the above equations (7) to (9), INRα0 = 0, INRα1 = 1, and INRα2 = 1. Therefore, from the above formulas (10) to (14),
αP0 = A0 + A1 = αMAX
αP1 = αP2 = αP3 = αP4 = A1 = αMIN
It becomes.
[0112]
That is, since αP1 to αP4 which are α values of the polygons PL1 to PL4 are small (αMIN), PL1 to PL4 look more transparent when viewed from the upper virtual camera VC, and the lines PL1 to PL4 are conspicuous. Disappear. On the other hand, since αP0, which is the α value of the polygon PL0, increases (αMAX), the virtual camera VC can see an image of the flame texture mapped to PL0.
[0113]
When the vector FL is parallel to FX (when FL is orthogonal to FY and FZ), INR0 = 0, INR1 = 1, INR2 = 0 from the above equations (4) to (6), and the above equation From (7) to (9), INRα0 = 1, INRα1 = 0, and INRα2 = 1. Therefore, from the above formulas (10) to (14),
αP0 = αP1 = αP3 = A1 = αMIN
αP2 = αP4 = A0 + A1 = αMAX
It becomes.
[0114]
That is, αP0, 1, 3 which are α values of the polygons PL0, 1, 3 become smaller, so that PL0, 1, 3 appear more transparent when viewed from the virtual camera VC in the direction of the vector FX. The lines PL 0, 1, 3 become inconspicuous. On the other hand, αP2 and 4 which are α values of the polygons PL2 and PL4 become large, so that the virtual camera VC can see the flame texture image mapped to PL2 and PL4.
[0115]
Also, when the vector FL is parallel to FZ (when FL is orthogonal to FX and FY), INR0 = 0, INR1 = 0, INR2 = 1 from the above equations (4) to (6), and the above equation From (7) to (9), INRα0 = 1, INRα1 = 1, and INRα2 = 0. Therefore, from the above formulas (10) to (14),
αP0 = αP2 = αP4 = A1 = αMIN
αP1 = αP3 = A0 + A1 = αMAX
It becomes.
[0116]
That is, αP0, 2, 4 which are α values of the polygons PL0, 2, 4 become smaller, so PL0, 2, 4 appear more transparent when viewed from the virtual camera VC in the direction of the vector FZ. The lines PL0, 2, 4 become inconspicuous. On the other hand, αP1 and 3 which are α values of the polygons PL1 and PL3 become large, and thus the virtual camera VC can see an image of the flame texture mapped to PL1 and PL3.
[0117]
Next, as shown in step S4 of FIG. 7, the vertex α value of the object OB (polygon) is obtained based on the obtained representative α values αP0 to α4 of the polygons PL0 to PL4. More specifically, given arithmetic processing (for example, averaging processing) is performed based on the representative α value set for one or a plurality of polygons to which the vertex of the object OB belongs, and the α value of the vertex of the object OB is obtained. .
[0118]
For example, in FIG. 9A, the vertex α values αV1, αV2, αV3, and αV4 of the vertices VX1, 2, 3, and 4 can be obtained by the following equations.
[0119]
αV1 = αP4 (15)
αV2 = (αP1 + αP2 + αP3 + αP4) / 4 (16)
αV3 = (αP0 + αP1 + αP2 + αP3 + αP4) / 5 (17)
αV4 = (αP0 + αP4) / 2 (18)
That is, as shown in FIG. 9A, the vertex VX1 belongs only to the polygon PL4. Therefore, the α value αV1 of the vertex VX1 becomes αP4, which is the representative α value of PL4 (formula (15)).
[0120]
The vertex VX2 belongs to the polygons PL1, 2, 3, and 4. Therefore, the α value αV2 of the vertex VX2 is an average value of αP1 to α4 that are representative α values of PL1 to PL4 (formula (16)).
[0121]
The vertex VX3 belongs to the polygons PL0, 1, 2, 3, and 4. Therefore, the α value αV3 of the vertex VX3 is an average value of αP0 to α4 that are representative α values of PL0 to PL4 (formula (17)).
[0122]
The vertex VX4 belongs to the polygons PL0 and PL4. Therefore, the α value αV4 of the vertex VX4 is an average value of αP0 and 4 which are representative α values of PL0 and PL4 (formula (18)).
[0123]
If the vertex α value is obtained as described above, the α value smoothly changes at the boundary of the polygon. Therefore, for example, even when the virtual camera moves around the object OB, the boundary of the polygon becomes inconspicuous when viewed from the virtual camera, and a more natural image can be generated.
[0124]
As shown in FIG. 9B, the α value αPIX of each pixel (dot) of the object (object after perspective transformation, polygon) is obtained by interpolating the vertex α values αV1 to α4 (for example, linear interpolation). Can be sought. Based on the obtained α value αPIX, α composition processing in units of pixels can be realized. In this case, the process for obtaining the α value of each pixel can be realized by a function of a drawing processor (such as a Gouraud shading function).
[0125]
2.3 Determination of drawing order
In the present embodiment, the polygon rendering order is determined by the method described below, and the polygons are rendered in the rendering buffer according to the determined rendering order. In this case, in the present embodiment, the polygon is drawn in the drawing buffer while performing the α composition processing (translucent processing) based on the α value obtained by the above-described method.
[0126]
For example, as shown in FIG. 10A, consider a case where objects OB1 to OB4 having the shape of FIG. 2 are arranged in the object space.
[0127]
In this case, in the present embodiment, first, based on the depth value (Z value) in the viewpoint coordinate system of the virtual camera VC, the drawing order for the objects OB1 to OB4 is changed as indicated by D1 in FIG. decide. That is, the Z sort of the objects OB1 to OB4 is performed. For example, the drawing order in the case of FIG. 10A is the order of OB4, OB1, OB3, and OB2.
[0128]
In this embodiment, as indicated by D2 to D5 in FIG. 10B, the drawing order of polygons included in these objects OB1 to OB4 is determined, and these polygons are sorted.
[0129]
In the case of FIG. 10A, first, polygons included in the innermost object OB4 are drawn in descending order of drawing priority. Next, the polygons included in OB1 are drawn in descending order of drawing priority. Next, the polygons included in OB3 are drawn in descending order of drawing priority. Finally, the polygons included in the foremost OB2 are drawn in descending order of drawing priority.
[0130]
By drawing a polygon by the above-described method, it is possible to realize an α synthesis process for a polygon without contradiction. Further, compared to the method of sorting all the polygons of the objects OB1 to OB4 at a time, the sorting processing load can be remarkably reduced.
[0131]
In this embodiment, the drawing order of polygons included in the object is determined by the following method.
[0132]
That is, in the present embodiment, as shown in FIG. 11A, an angle θ (cos θ formed by the polygon PL1 (PL2 to PL4) of the object OB and the virtual camera VC. In a broad sense, a relative directional relationship. Similarly, the drawing order of the polygons PL1 to PL4 is determined.
[0133]
For example, in FIG. 11A, θ is between 0 and 90 degrees, and the polygons PL1 and PL4 are located in front as viewed from the virtual camera VC. In this case, first the polygon PL0 is drawn, then the polygons PL2 and PL3 are drawn, and finally the polygons PL1 and PL4 are drawn.
[0134]
Note that there is no problem even if the polygon PL0 on the bottom surface is drawn first, unless there is a situation where the flame object OB is viewed from below. That is, even if the polygon PL0 is drawn first, an α composition process without contradiction can be realized. Therefore, the drawing priority order of the polygon PL0 is always set to the highest order (order of drawing first).
[0135]
Further, at the position of the virtual camera VC in FIG. 11A, the polygons PL1 and PL4 and PL2 and PL3 do not overlap each other, and it is not necessary to sort these polygons. Accordingly, the drawing order between the polygons PL1 and PL4 and the drawing order between the PL2 and PL3 are arbitrary.
[0136]
In FIG. 11B, θ is between 90 and 180 degrees, and the polygons PL3 and PL4 are positioned in front of the virtual camera VC. In this case, first the polygon PL0 is drawn, then the polygons PL1 and PL2 are drawn, and finally the polygons PL3 and PL4 are drawn. The drawing order between polygons PL1 and PL2 and between PL3 and PL4 is arbitrary.
[0137]
In FIG. 11C, θ is between 180 and 270 degrees, and the polygons PL2 and PL3 are located in front as viewed from the virtual camera VC. In this case, first the polygon PL0 is drawn, then the polygons PL1 and PL4 are drawn, and finally the polygons PL2 and PL3 are drawn. The drawing order between polygons PL1 and PL4 and between PL2 and PL3 is arbitrary.
[0138]
In FIG. 11D, θ is between 270 and 360 degrees, and the polygons PL1 and PL2 are located in front as viewed from the virtual camera VC. In this case, first the polygon PL0 is drawn, then the polygons PL3 and PL4 are drawn, and finally the polygons PL1 and PL2 are drawn. The drawing order between polygons PL3 and PL4 and between PL1 and PL2 is arbitrary.
[0139]
Thus, in the present embodiment, focusing on the fact that the shape of the object OB is fixed to a specific shape (a shape in which polygons are arranged radially from the reference line), the angle formed between the surface of the polygon and the orientation of the virtual camera The polygon rendering order is uniquely determined according to θ (inner product value, relative directional relationship). Therefore, since polygons can be sorted without determining the polygon depth value, the sort processing load can be significantly reduced.
[0140]
In the present embodiment, as described above, the α value of the polygon is also set according to the angle θ formed by the polygon surface and the orientation of the virtual camera. Therefore, since the angle θ (more specifically, the inner product value) used for obtaining the α value can be effectively used to determine the polygon rendering order, the processing load can be further reduced.
[0141]
2.4 Particle area
In order to make the image of the object OB more realistic, it is desirable to employ a particle system using particle primitives (particles composed of points, lines, or faces).
[0142]
Therefore, in the present embodiment, as shown in FIG. 12, a plurality of particle areas PTA1, PTA2, PTA3, and PTA4 (particle existence areas) are set, and in these PTA1 to PTA1-4, particle primitives that disappear with a given lifetime Is generated.
[0143]
In FIG. 12, these particle areas PTA1 to PTA1 are divided by polygons PL1 to PL4 included in the object OB.
[0144]
In this way, if particle primitives are generated in each of the particle areas PTA1 to PTA4, compared to the case where the object OB is simply composed of only the polygons PL0 to PL4, there is a sense of volume and looks three-dimensional. You can express the flame. Thereby, the virtual reality of the player can be further improved.
[0145]
In the present embodiment, sprite polygons (polygons displayed on a billboard) to which textures representing particles are mapped are used as particle primitives. By doing so, the drawing load can be remarkably reduced as compared with the case where a large number of particles expressed by primitive points are generated to express a flame or the like. That is, a flame occupying a wider range can be expressed with a small number of primitives (number of polygons).
[0146]
However, primitive points, primitive lines, or the like may be used as particle primitives instead of sprite polygons.
[0147]
In order to realize more realistic particle representation, particle primitives are given various attributes such as color and alpha value (translucency), and particle primitives are generated, moved, and disappeared according to given rules. It is desirable to express an irregular flame. That is, the initial speed (initial moving direction) of the particle primitive is changed randomly, or the lifetime of the particle primitive is changed randomly. By doing so, it is possible to realize a realistic image expression that looks like a flame in the real world. The disappearance of the particle primitive can be realized by controlling the α value of the particle primitive so that the particle primitive gradually becomes transparent with time.
[0148]
Now, when the particle area is provided and the particle primitive is generated as described above, it becomes a problem how to determine the drawing order for the particle areas PTA1 to PTA4 (particle primitive).
[0149]
In the present embodiment, the drawing order for the particle area is also determined according to the relative directional relationship (angle θ, inner product value) between the polygon surface and the orientation of the virtual camera.
[0150]
For example, in FIG. 13A, θ is between 0 and 90 degrees, and the polygons PL1 and PL4 are located on the front side when viewed from the virtual camera VC. In this case, the polygon PL0 is first drawn, and then the particle primitive in the particle area PTA3 is drawn. The polygons PL2 and PL3 are drawn, and then the particle primitives in the particle areas PTA2 and 4 are drawn. Then, polygons PL1 and PL4 are drawn, and finally a particle primitive in the particle area PTA1 is drawn.
[0151]
The drawing order between PL2 and PL3, between PTA2 and PTA4, and between PL1 and PL4 is arbitrary. In each particle area, it is desirable to draw particle primitives while performing Z-sorting.
[0152]
In FIG. 13B, θ is between 90 and 180 degrees, and the polygons PL3 and PL4 are located in front as viewed from the virtual camera VC. In this case, the polygon PL0 is first drawn, and then the particle primitive in the particle area PTA2 is drawn. The polygons PL1 and PL2 are drawn, and then the particle primitives in the particle areas PTA1 and 3 are drawn. Then, the polygons PL3 and PL4 are drawn, and finally the particle primitive in the particle area PTA4 is drawn. The drawing order between PL1 and PL2, between PTA1 and PTA3, and between PL3 and PL4 is arbitrary.
[0153]
In FIG. 14A, θ is between 180 and 270 degrees, and the polygons PL2 and PL3 are located in front as viewed from the virtual camera VC. In this case, the polygon PL0 is first drawn, and then the particle primitive in the particle area PTA1 is drawn. The polygons PL1 and PL4 are drawn, and then the particle primitives in the particle areas PTA2 and 4 are drawn. Then, the polygons PL2 and PL3 are drawn, and finally the particle primitive in the particle area PTA3 is drawn. The drawing order between PL1 and PL4, between PTA2 and PTA4, and between PL2 and PL3 is arbitrary.
[0154]
In FIG. 14B, θ is between 270 and 360 degrees, and the polygons PL1 and PL2 are located in front as viewed from the virtual camera VC. In this case, the polygon PL0 is first drawn, and then the particle primitive in the particle area PTA4 is drawn. The polygons PL3 and PL4 are drawn, and then the particle primitives in the particle areas PTA1 and 3 are drawn. The polygons PL1 and PL2 are drawn, and finally the particle primitive in the particle area PTA2 is drawn. The drawing order between PL3 and PL4, between PTA1 and PTA3, and between PL1 and PL2 is arbitrary.
[0155]
Note that the directional relationship (angle θ) between the polygon surface and the virtual camera VC is specifically determined by the method shown in FIG.
[0156]
For example, in FIG. 15, FL is a unit vector starting from the center point CP of the object OB and facing the direction of VC, FX is a unit vector starting from CP and orthogonal to PL2 and PL4, and FZ is the starting point of CP. And unit vectors orthogonal to PL1 and PL3 (see FIG. 8).
[0157]
In the present embodiment, the inner product values INR1 and INR2 of the following equation are obtained using these vectors.
[0158]
INR1 = FX ・ FL (19)
INR2 = FZ · FL (20)
When INR1> 0 and INR2> 0, it is determined that the virtual camera VC is positioned in front of PL1 and PL4, and the drawing order is as shown in FIG.
[0159]
If INR1 ≦ 0 and INR2> 0, it is determined that the virtual camera VC is positioned in front of PL3 and PL4, and the drawing order is as shown in FIG. 13B.
[0160]
When INR1 ≦ 0 and INR2 ≦ 0, it is determined that the virtual camera VC is positioned in front of PL2 and PL3, and the drawing order is the order shown in FIG.
[0161]
When INR1> 0 and INR2 ≦ 0, it is determined that the virtual camera VC is positioned in front of PL1 and PL2, and the drawing order is as shown in FIG. 14B.
[0162]
In this case, in the present embodiment, as these inner product values INR1, INR2 (expressions (19), (20)), inner product values INR1, INR2 (expressions (5), (6)) obtained at the time of setting the α value. ) Can be used as is. By doing so, the inner product values INR1 and INR2 obtained at the time of setting the α value can be used effectively, and the processing load can be reduced.
[0163]
2.5 Particle generation
In this embodiment, as shown in FIG. 16, particle primitive generators G1 to G4 (occurrence locations) are set for the respective particle areas PTA1 to PTA4. The generators G1 to G4 generate particle primitives having a given lifetime at a given initial speed.
[0164]
For example, the area of the particle area PTA1 can be defined as (X0, Z0), (X0 + XSZ, Z0 + ZSZ). In this case, PTA1 is defined so that the area of the particle area PTA1 does not overlap the polygons PL1 and PL4 dividing PTA1.
[0165]
At this time, the positions GP1 to GP4 of the generators G1 to G4 can be expressed by the following equations.
[0166]
GP1
= (X0 + XSZ × VLMIN, Z0 + ZSZ × VLMIN) (21)
GP2
= (X0 + XSZ × VLMAX, Z0 + ZSZ × VLMIN) (22)
GP3
= (X0 + XSZ × VLMIN, Z0 + ZSZ × VLMAX) (23)
GP4
= (X0 + XSZ × VLMAX, Z0 + ZSZ × VLMAX) (24)
Here, VLMIN and VLMAX are parameters for defining the position of the generator, and a relationship of 0 <VLMIN <VLMAX is established.
[0167]
By determining the position as in the above equations (21) to (24), the generators G1 to G4 are positioned inside the particle area.
[0168]
There are various parameter setting methods for particle primitives. In this embodiment, in order to reduce the processing load, only the following parameters are provided as attribute information of each particle primitive. ing.
(PX, PY, PZ), (VCX, VCY, VCZ), LIFE
Here, (PX, PY, PZ) are parameters indicating the generation position of the particle primitive. That is, it is a parameter representing one of the above GP1 to GP4.
[0169]
Further, (VCX, VCY, VCZ) is a parameter representing the initial velocity of the particle primitive, and LIFE is a parameter representing the current life (age) of the particle primitive.
[0170]
As another parameter, LIFEMAX is prepared in this embodiment. This LIFEMAX is a parameter representing the lifetime of the particle primitive.
[0171]
FIG. 17 shows a flowchart of the particle processing of this embodiment.
[0172]
First, it is determined whether or not it is frame update (drawing buffer update) (step S21). This can be determined based on an interrupt generated at the timing of vertical synchronization by the hardware of the image generation system.
[0173]
If it is determined that the frame is to be updated, the particle number NUM is set to 0 (step S22). Then, the LIFE of the NUM-th particle primitive is incremented by 1 (step S23).
[0174]
Next, it is determined whether LIFE> LIFEMAX (step S24). If LIFE> LIFEMAX, LIFE is reset to 0, and the generation positions PX, PY, PZ and initial speeds VCX, VCY, VCZ are reset (step S25). That is, the generation position and initial velocity of the particle primitive exceeding the lifetime are reset. In this case, the generator for generating the particle primitive and the initial speed of the particle primitive are determined based on a random number.
[0175]
Next, the drawing position (X, Y, Z) of the particle primitive is determined as in the following equation (step S26).
[0176]
X = PX + VCX × LIFE (25)
Y = PY + VCY × LIFE (26)
Z = PZ + VCZ × LIFE (27)
That is, the position of each particle primitive is specified by its generation position, initial velocity, and LIFE.
[0177]
Next, the particle number NUM is incremented by 1 (step S27). Then, it is determined whether or not NUM> NUMMAX (step S28). If NUM ≦ NUMMAX, the process returns to step S23 to process the next particle primitive.
[0178]
On the other hand, if NUM> NUMMAX, NUM particle primitives are Z-sorted and drawn in the drawing buffer (step S29). Thereby, the drawing of the particle primitive in the frame is completed.
[0179]
When the particle primitive is generated as described above, there are the following problems. That is, if a particle primitive generated in one particle area goes out of the particle area and enters another particle area, the particle primitive is drawn in the wrong drawing order. There is a risk that.
[0180]
Therefore, in the present embodiment, as shown in FIG. 18A, the movement of the particle primitive is limited so that the particle primitive moves only within the particle area where the particle primitive is generated. As a result, as shown in FIG. 18A, for example, the particle primitive generated in the particle area PTA1 moves and disappears only in PTA1. Further, the particle primitive generated in the particle area PTA3 moves only within the PTA3 and disappears.
[0181]
In this embodiment, such movement limitation is realized by controlling the initial speed and life of the particle primitive.
[0182]
For example, in the present embodiment, the initial velocity is determined as follows when setting the initial conditions of the particle primitive or resetting the initial conditions in step S25 of FIG.
[0183]
For example, when the particle primitive is generated from the generator G1 as shown in FIG. 18B, the initial velocity (VCX, VCY, VCZ) of the particle primitive under the condition of VCX> 0 and VCZ> 0. ) Is determined by a random number.
[0184]
When the particle primitive is generated from the generator G2 as shown in FIG. 18C, the initial velocity (VCX, VCY, VCZ) of the particle primitive under the condition of VCX <0, VCZ> 0. ) Is determined by a random number.
[0185]
When the particle primitive is generated from the generator G3 as shown in FIG. 18D, the initial velocity (VCX, VCY, VCZ) of the particle primitive under the condition that VCX> 0 and VCZ <0. ) Is determined by a random number.
[0186]
Further, when the particle primitive is generated from the generator G4 as shown in FIG. 18E, the initial velocity (VCX, VCY, VCZ) of the particle primitive under the condition of VCX <0, VCZ <0. ) Is determined by a random number.
[0187]
Also, if the initial velocity is too high, the particle primitive may come out of the particle area immediately. For this reason, for example, for the initial velocity (VCX, VCY, VCZ) of the particle primitive generated from the generator G1, the following limitation is applied.
0 <ABS (VCX) × LIFEMAX <XSZ × (1-VLMIN) (28)
0 <ABS (VCZ) × LIFEMAX <ZSZ × (1-VLMIN) (29)
Here, ABS (X) is a function that returns the absolute value of X as a return value. Further, as described above, LIFEMAX is a parameter representing the life, XSZ and ZSZ are parameters for defining the particle area, and VLMIN is a parameter for defining the position of the generator.
[0188]
As described above, in this embodiment, it is succeeded to ensure that the particle primitive does not go out of the particle area only by setting or resetting the initial condition of the particle primitive.
[0189]
3. Processing of this embodiment
Next, a detailed example of the processing of this embodiment will be described using the flowcharts of FIGS. 19 and 20.
[0190]
First, flame objects (see FIG. 2) are Z-sorted in the viewpoint (camera) coordinate system (step S31). That is, as described with reference to FIGS. 10A and 10B, first, Z sort is performed on the flame objects OB1 to OB4.
[0191]
Next, the object number I = 0 is set (step S32). Then, a vector FL (see FIG. 8) is obtained based on the coordinates of the center point (representative point) of the I-th flame object and the coordinates of the virtual camera (step S33).
[0192]
Next, an inner product value of the vectors FX, FY, FZ on the local coordinate system of the I-th flame object and the obtained FL is obtained (step S34). Then, based on the calculated inner product value, the α value and drawing order for the flame polygon (PL0 to PL4) and the particle area (PTA1 to PTA4) are determined (step S35).
[0193]
Next, the base polygon (PL0) of the flame object is drawn (step S36). Then, the particle primitive in the particle area having the first drawing priority is drawn (step S37).
[0194]
Next, the first and second drawing polygons having the drawing priority are drawn (step S38). Then, the particle primitives in the second and third drawing priority order particle areas are drawn (step S39).
[0195]
Next, the 3rd and 4th drawing priority flame polygons are drawn (step S40). Then, the particle primitive in the particle area of the fourth drawing priority is drawn (step S41).
[0196]
Next, the object number I is incremented by 1 (step S42). Then, it is determined whether or not I> IMAX. If I ≦ IMAX, the process returns to step S33 in FIG. On the other hand, if I> IMAX, the process ends.
[0197]
4). Hardware configuration
Next, an example of a hardware configuration capable of realizing the present embodiment will be described with reference to FIG.
[0198]
The main processor 900 operates based on a program stored in the CD 982 (information storage medium), a program transferred via the communication interface 990, or a program stored in the ROM 950 (one of information storage media). Various processes such as processing, image processing, and sound processing are executed.
[0199]
The coprocessor 902 assists the processing of the main processor 900, has a product-sum calculator and a divider capable of high-speed parallel calculation, and executes matrix calculation (vector calculation) at high speed. For example, if a physical simulation for moving or moving an object requires processing such as matrix operation, a program operating on the main processor 900 instructs (requests) the processing to the coprocessor 902. )
[0200]
The geometry processor 904 performs geometry processing such as coordinate transformation, perspective transformation, light source calculation, and curved surface generation, has a product-sum calculator and a divider capable of high-speed parallel computation, and performs matrix computation (vector computation). Run fast. For example, when processing such as coordinate transformation, perspective transformation, and light source calculation is performed, a program operating on the main processor 900 instructs the geometry processor 904 to perform the processing.
[0201]
The data decompression processor 906 performs a decoding process for decompressing the compressed image data and sound data, and a process for accelerating the decoding process of the main processor 900. As a result, a moving image compressed by the MPEG method or the like can be displayed on the opening screen, the intermission screen, the ending screen, or the game screen. Note that the image data and sound data to be decoded are stored in the ROM 950 and the CD 982 or transferred from the outside via the communication interface 990.
[0202]
The drawing processor 910 performs drawing (rendering) processing of an object composed of primitives (primitive surfaces) such as polygons and curved surfaces at high speed. When drawing an object, the main processor 900 uses the function of the DMA controller 970 to pass the object data to the drawing processor 910 and transfer the texture to the texture storage unit 924 if necessary. Then, the rendering processor 910 renders the object in the frame buffer 922 at high speed while performing hidden surface removal using a Z buffer or the like based on the object data and texture. The drawing processor 910 can also perform 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.
[0203]
The sound processor 930 includes a multi-channel ADPCM sound source and the like, and generates high-quality game sounds such as BGM, sound effects, and sounds. The generated game sound is output from the speaker 932.
[0204]
Operation data from the game controller 942 (lever, button, chassis, pad type controller, gun type controller, etc.), save data from the memory card 944, and personal data are transferred via the serial interface 940.
[0205]
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.
[0206]
The RAM 960 is used as a work area for various processors.
[0207]
The DMA controller 970 controls DMA transfer between the processor and memory (RAM, VRAM, ROM, etc.).
[0208]
The CD drive 980 drives a CD 982 (information storage medium) in which programs, image data, sound data, and the like are stored, and enables access to these programs and data.
[0209]
The communication interface 990 is an interface for transferring data to and from the outside via a network. In this case, as a network connected to the communication interface 990, a communication line (analog telephone line, ISDN), a high-speed serial bus, or the like can be considered. By using a communication line, data transfer via the Internet becomes possible. Further, by using the high-speed serial bus, data transfer with other image generation systems becomes possible.
[0210]
All of the means of the present invention may be realized (executed) only by hardware, or only by a program stored in an information storage medium or a program distributed via a communication interface. Also good. Alternatively, it may be realized by both hardware and a program.
[0211]
When each means of the present invention is realized by both hardware and a program, the information storage medium stores a program for realizing each means of the present invention using hardware. Become. More specifically, the program instructs each processor 902, 904, 906, 910, 930, etc., which is hardware, and passes data if necessary. Each of the processors 902, 904, 906, 910, 930 and the like implements each unit of the present invention based on the instruction and the passed data.
[0212]
FIG. 22A shows an example in which the present embodiment is applied to an arcade game system (image generation system). The player enjoys the game by operating the gun-type controllers 1102 and 1103 and the like while viewing the game images displayed on the displays 1100 and 1101. Various processors and various memories are mounted on the built-in system board (circuit board) 1106. A program (data) for realizing each means of the present invention is stored in a memory 1108 which is an information storage medium on the system board 1106. Hereinafter, this program is referred to as a storage program (storage information).
[0213]
FIG. 22B shows an example in which the present embodiment is applied to a home game system (image generation system). The player enjoys the game by operating the gun-type controllers 1202 and 1204 while watching the game image displayed on the display 1200. In this case, the stored program (stored information) is stored in a CD 1206, which is an information storage medium that is detachable from the main system, or in memory cards 1208, 1209, and the like.
[0214]
FIG. 22C shows a host device 1300 and terminals 1304-1 to 1304-n connected to the host device 1300 via a network 1302 (a small-scale network such as a LAN or a wide area network such as the Internet). An example in which the present embodiment is applied to a system including (game machine, mobile phone, television) is shown. In this case, the storage program (storage information) is stored in an information storage medium 1306 such as a magnetic disk device, a magnetic tape device, or a memory that can be controlled by the host device 1300, for example. When the terminals 1304-1 to 1304-n can generate game images and game sounds stand-alone, the host device 1300 receives a game program and the like for generating game images and game sounds from the terminal 1304-. 1 to 1304-n. On the other hand, if it cannot be generated stand-alone, the host device 1300 generates game images and game sounds, which are transmitted to the terminals 1304-1 to 1304-n and output at the terminals.
[0215]
In the case of the configuration shown in FIG. 22C, each unit of the present invention may be realized by being distributed between a host device (server) and a terminal. Further, the above storage program (storage information) for realizing each means of the present invention may be distributed and stored in the information storage medium of the host device (server) and the information storage medium of the terminal.
[0216]
The terminal connected to the network may be a home game system or an arcade game system. When the arcade game system is connected to a network, the save information storage device can exchange information with the arcade game system and exchange information with the home game system. It is desirable to use (memory card, portable game device).
[0217]
The present invention is not limited to that described in the above embodiment, and various modifications can be made.
[0218]
For example, the shape of the object of the present invention is not limited to that described in FIGS. 2 and 4A to 4D, and various shapes can be adopted.
[0219]
Further, the α value setting method is not limited to the method described with reference to FIGS. 6A to 9B, and various modifications equivalent to this can be performed.
[0220]
Further, the method for determining the drawing order is not limited to the method described with reference to FIGS.
[0221]
Further, the particle primitive processing method is not limited to the method described with reference to FIGS.
[0222]
In the invention according to the dependent claims of the present invention, a part of the constituent features of the dependent claims can be omitted. Moreover, the principal part of the invention according to one independent claim of the present invention can be made dependent on another independent claim.
[0223]
The present invention can also be applied to various games (such as fighting games, shooting games, robot battle games, sports games, competitive games, role playing games, music playing games, dance games, etc.).
[0224]
The present invention is also applicable to various image generation systems (game 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, and a system board for generating game images. Applicable.
[Brief description of the drawings]
FIG. 1 is an example of a functional block diagram of an image generation system according to an embodiment.
FIG. 2 is a diagram showing an example of the shape of an object used in the present embodiment.
FIGS. 3A, 3B, and 3C are examples of textures (movie textures) mapped to objects.
FIGS. 4A to 4D are diagrams for explaining another example of the shape of an object.
FIGS. 5A to 5D are diagrams for explaining problems when the object having the shape of FIG. 2 is used.
6A to 6D are diagrams for explaining a method for setting an α value. FIG.
FIG. 7 is a flowchart for explaining a specific example of an α value setting method;
FIG. 8 is a diagram for explaining a specific example of an α value setting method;
FIGS. 9A and 9B are diagrams for explaining a method for obtaining the α value of a vertex and the α value of a pixel.
FIGS. 10A and 10B are diagrams for explaining sort processing according to the present embodiment.
FIGS. 11A to 11D are diagrams for explaining a method of determining a polygon rendering order according to a polygon plane and a virtual camera orientation.
FIG. 12 is a diagram for explaining setting of a particle area and generation of a particle primitive.
FIGS. 13A and 13B are diagrams for explaining a method for determining the drawing order of polygons and particle areas in accordance with the polygon plane and the orientation of the virtual camera.
FIGS. 14A and 14B are diagrams for explaining a method for determining the drawing order of polygons and particle areas in accordance with the polygon plane and the orientation of the virtual camera.
FIG. 15 is a diagram for explaining a method of determining a directional relationship between a polygon surface and a virtual camera direction using a vector inner product value;
FIG. 16 is a diagram for explaining a particle primitive generator;
FIG. 17 is a flowchart for explaining particle processing;
FIGS. 18A to 18E are diagrams for explaining a technique for restricting the movement of particle primitives.
FIG. 19 is a flowchart illustrating a detailed example of processing according to the present embodiment.
FIG. 20 is a flowchart illustrating a detailed example of processing according to the embodiment.
FIG. 21 is a diagram illustrating an example of a hardware configuration capable of realizing the present embodiment.
FIGS. 22A, 22B, and 22C are diagrams illustrating examples of various types of systems to which the present embodiment is applied.
[Explanation of symbols]
VC virtual camera
OB object
PL0 to PL4 polygon
RL reference line
FX, FY, FZ vectors
VX1 to VX4 vertex
PTA1-PTA4 particle area
CP center point
100 processor
110 Object space setting part
112 α value setting part
114 Particle processing unit
116 Drawing order determination unit
120 Drawing part
122 Texture mapping part
124 α synthesis unit
160 Operation unit
170 Storage unit
172 Main memory
174 Drawing buffer
176 texture storage
180 Information storage medium
190 Display
192 sound output section
194 Portable information storage device
196 Communication Department

Claims (7)

An image generation system for generating an image,
Particle processing means for performing a process of generating a plurality of particle primitives that disappear at a given lifetime in each of the first to M-th particle areas;
Drawing order determining means for determining a drawing order for the first to Mth particle areas;
In descending order particle area priority of drawing order, look including a means for drawing the particles primitives generated by the particle area,
The drawing order determining means is
According to the relative direction relationship between at least one primitive surface among the first to Nth primitive surfaces that divide the first to Mth particle areas and the orientation of the virtual camera, An image generation system for determining a drawing order for M particle areas or a drawing order for the first to M-th particle areas and the first to N-th primitive surfaces . In claim 1 ,
The particle processing means is
The particle primitive generated in the Lth (1 ≦ L ≦ M) particle area in the first to Mth particle areas is moved so as to move in the Lth particle area. image generation system and limits the. In claim 2 ,
The particle processing means is
An image generation system, wherein movement of particle primitives is limited by controlling at least one of an initial speed and a lifetime of particle primitives. Particle processing means for performing a process of generating a plurality of particle primitives that disappear at a given lifetime in each of the first to M-th particle areas;
Drawing order determining means for determining a drawing order for the first to Mth particle areas;
A high particle area priority of drawing order sequentially, cause the computer to function as a means for drawing the particles primitives generated by the particle area,
The drawing order determining means is
According to the relative direction relationship between at least one primitive surface among the first to Nth primitive surfaces that divide the first to Mth particle areas and the orientation of the virtual camera, A program for determining a drawing order for M particle areas or a drawing order for the first to Mth particle areas and the first to Nth primitive surfaces . In claim 4 ,
The particle processing means is
The particle primitive generated in the Lth (1 ≦ L ≦ M) particle area in the first to Mth particle areas is moved so as to move in the Lth particle area. program and limits the. In claim 5 ,
The particle processing means is
A program for restricting the movement of particle primitives by controlling at least one of the initial speed and lifetime of the particle primitives. An information storage medium readable by a computer, the information storage medium characterized by storing one of the programs of Claims 4 to 6.

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