JP4756064B2 - Image generating apparatus, image generating method, and program - Google Patents

Description

  The present invention relates to an image generation device, an image generation method, and a program that can appropriately express the glare of a light source.

  Conventionally, various game devices (video game devices and the like) have been developed for home use and business use. Such a game device generally arranges an object such as a character in a virtual space and displays a game image viewed from a predetermined viewpoint.

  In recent years, improvement in hardware performance, development of image processing technology, and the like have made it possible to generate high-precision game images at high speed, and the player can enjoy the game as if it were in a virtual space.

  As an example, an image with improved reality is generated when a light source (light source object) in a virtual space is displayed. Specifically, in a scene where a street lamp is lit at night, a scene in which light spreads around the street lamp due to glow, halo, or the like is expressed, and the reality of the light source is enhanced.

  Recently, when expressing such a light source, a technique that reduces the processing load and draws in consideration of the optical axis or the like and can increase the reality of the light source has been disclosed (for example, Patent Document 1).

JP 2002-251629 (page 5-7, FIG. 1)

The above-described light source expression method using glow or the like can generally increase the reality of the light source when used in a nighttime or dark scene. This kind of expression is also used in daytime outdoor scenes, but it is often not very effective due to the bright surroundings.
For example, even if the sun during the daytime is expressed using glow or the like in an outdoor scene, the sun is hardly emphasized because the sky is bright. That is, even if an image including the sun in the field of view is generated by the conventional expression method, the sun is not felt dazzling by the player, and the reality is insufficient.

  Therefore, there has been a demand for a new expression technique that can more appropriately express the glare of such a light source such as the daytime sun.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image generation device, an image generation method, and a program capable of appropriately expressing the glare of a light source.

  An image generation apparatus according to a first aspect of the present invention includes an adjustment image generation unit, a calculation unit, and an image drawing unit, and a virtual space in which a plurality of objects including a light source object (for example, a sun object) are arranged. Is an image generation device that generates a view field image viewed from a predetermined viewpoint, and is configured as follows.

  First, the adjustment image generation unit generates an adjustment image having a predetermined shape for adjusting the brightness of the view field image excluding the light source object (not including the light source object). As an example, a light source object is cut out from the entire field of view, and an adjustment image for reducing the brightness of a field image other than the light source object is generated. In addition, the calculation unit calculates the brightness to be adjusted by the adjustment image based on the arrangement state of the light source object in the field of view (for example, an angle formed by the direction from the viewpoint to the light source object and the line-of-sight direction). Then, the image drawing unit generates a projection image of each object arranged in the field of view, and draws a field image obtained by synthesizing the adjustment image with the projection image.

In this way, by synthesizing the adjustment image with the projection image, a field-of-view image with reduced lightness is generated without changing the light source object. Note that the brightness to be reduced varies depending on the arrangement position of the light source object in the field of view. For example, if the position of the light source object is far from the line-of-sight direction (the center of the field-of-view image), a view image with a slight decrease in brightness is drawn. Conversely, if the position of the light source object is close to the line-of-sight direction, Draw a field-of-view image with reduced image quality.
That is, since the brightness of the light source object is left as it is, the brightness of the light source object is lowered, so that the brightness of the light source object is relatively emphasized and the light source object feels more dazzling for the player.
As a result, the glare of the light source can be appropriately expressed.

  An image generation apparatus according to a second aspect of the present invention includes a mask image generation unit, a calculation unit, and an image drawing unit, and a virtual space in which a plurality of objects including a light source object (for example, a sun object) are arranged. Is an image generation device that generates a view field image viewed from a predetermined viewpoint, and is configured as follows.

  First, the mask image generation unit generates a mask image in which the light source object is removed from the entire field of view based on the viewpoint. That is, a mask image that covers the light source object without covering it is generated. Further, the calculation unit sets the transparency (for example, alpha value) to be set in the mask image to the arrangement state of the light source object in the field of view (for example, the angle formed between the direction from the viewpoint to the light source object and the line of sight). Calculate based on Then, the image drawing unit generates a projection image obtained by projecting and transforming each object arranged in the field of view, and draws a field of view image obtained by synthesizing the projection image with a mask image set with transparency.

In this way, by synthesizing the mask image in which the transparency is set to the projection image, a field-of-view image in which the brightness is adjusted according to the transparency of the mask image is generated without changing the light source object. As an example, if the mask image is black, the lower the transparency of the mask image (the more opaque it is), the lower the brightness of the field-of-view image covered with the mask image. That is, the lightness to be reduced is determined according to the transparency of the mask image, and the transparency of the mask image varies depending on the arrangement position of the light source object in the field of view. For example, when the position of the light source object is away from the line-of-sight direction (the center of the view image), the transparency of the mask image is set high, and the brightness of the covered view image is slightly reduced. Conversely, when the position of the light source object is close to the line-of-sight direction, the transparency of the mask image is set low, and the brightness of the covered field-of-view image is considerably reduced.
That is, since the brightness of the light source object is left as it is, the brightness of the light source object is lowered, so that the brightness of the light source object is relatively emphasized and the light source object feels more dazzling for the player.
As a result, the glare of the light source can be appropriately expressed.

The mask image generation unit may generate a mask image excluding the light source object by cutting out the shape of the light source object in the view from a black rectangular image covering the entire view.
In this case, when the transparency of the black mask image is large (not so opaque), it becomes light gray, and the brightness of the covered view field image is reduced. Conversely, when the transparency is small (when it becomes quite opaque), the color becomes dark gray and the brightness of the covered field-of-view image is greatly reduced.

The calculation unit may calculate the transparency based on an angle formed by the direction from the viewpoint to the light source object and the line-of-sight direction.
For example, the greater the angle formed between the direction from the viewpoint to the light source object and the line-of-sight direction, the greater the transparency (for example, the smaller alpha value), and the smaller the angle formed, the smaller the transparency (for example, the greater the alpha value). ) Is calculated. As an example, if the transparency of the black mask image is calculated high (not so opaque), the brightness of the covered view image is slightly reduced. On the other hand, if the transparency is calculated to be low (becomes quite opaque), the brightness of the covered view image is greatly reduced.
Thereby, if the light source object is away from the center of the view image, a slightly dark view image is drawn. Conversely, if the light source object is close to the center of the view image, a considerably dark view image is drawn.

The calculation unit may correct the calculated transparency based on a shielding ratio indicating a shielded ratio when the light source object is shielded by another object.
Specifically, a case where the light source object is in the line-of-sight direction (the center of the field-of-view image) and the transparency of the black mask image is calculated to be low (substantially opaque) will be described as an example. In this case, when the shielding ratio of the light source object is large, the transparency is corrected to be considerably higher than the calculated value. Conversely, when the shielding ratio is small, the transparency is corrected so as to be slightly higher than the calculated value. That is, even when the light source object is arranged at the same position, the transparency is corrected based on the shielding ratio, and the brightness of the covered view image is also adjusted.
Thereby, not only the arrangement position of the light source object but also the view field image adjusted according to the shielding ratio is drawn.

The image generation apparatus further includes a time measuring unit that measures an elapsed time in a state where the light source object is disposed in the field of view,
The calculation unit may sequentially increase the transparency as the elapsed time counted increases.
In this case, for example, even if the light source object is at the center of the visual field screen and the visual field image covered with the black mask image with low transparency is drawn quite darkly, the transparency of the mask image as time passes as it is Since the field of view image that is covered gradually becomes darker and darker, the player's eyes can be felt as they are gradually getting used to it.

  An image generation method according to a third aspect of the present invention is an image generation device that generates a visual field image in which a virtual space in which a plurality of objects including a light source object (for example, a sun object) is arranged is viewed from a predetermined viewpoint. The image generation method in FIG. 1 includes an adjustment image generation step, a calculation step, and an image drawing step, and is configured as follows.

  First, in the adjustment image generation step, an adjustment image having a predetermined shape for adjusting the brightness of the view field image excluding the light source object (not including the light source object) is generated. As an example, a light source object is cut out from the entire field of view, and an adjustment image for reducing the brightness of a field image other than the light source object is generated. In the calculation step, the brightness to be adjusted by the adjustment image is calculated based on the arrangement state of the light source object in the field of view (for example, the angle formed between the direction from the viewpoint to the light source object and the line-of-sight direction). In the image drawing step, a projection image of each object arranged in the field of view is generated, and a field image obtained by synthesizing the adjustment image with the projection image is drawn.

In this way, by synthesizing the adjustment image with the projection image, a field-of-view image with reduced lightness is generated without changing the light source object. Note that the brightness to be reduced varies depending on the arrangement position of the light source object in the field of view. For example, if the position of the light source object is far from the line-of-sight direction (the center of the field-of-view image), a view image with a slight decrease in brightness is drawn. Conversely, if the position of the light source object is close to the line-of-sight direction, Draw a field-of-view image with reduced image quality.
That is, since the brightness of the light source object is left as it is, the brightness of the light source object is lowered, so that the brightness of the light source object is relatively emphasized and the light source object feels more dazzling for the player.
As a result, the glare of the light source can be appropriately expressed.

  A program according to a fourth aspect of the present invention is configured to cause a computer (including an electronic device) to function as the above-described image generation device.

  This program can be recorded on a computer-readable information recording medium such as a compact disk, flexible disk, hard disk, magneto-optical disk, digital video disk, magnetic tape, and semiconductor memory.

  The above program can be distributed and sold via a computer communication network independently of the computer on which the program is executed. The information recording medium can be distributed and sold independently of the computer.

  ADVANTAGE OF THE INVENTION According to this invention, the glare of a light source can be expressed appropriately.

  Embodiments of the present invention will be described below. In the following, for ease of understanding, an embodiment in which the present invention is applied to a game device will be described. However, the present invention can be similarly applied to information processing devices such as various computers, PDAs, and mobile phones. it can. That is, the embodiment described below is for explanation, and does not limit the scope of the present invention. Therefore, those skilled in the art can employ embodiments in which each or all of these elements are replaced with equivalent ones, and these embodiments are also included in the scope of the present invention.

(Embodiment 1)
FIG. 1 is a schematic diagram showing a schematic configuration of a typical game device in which the image generating device according to the embodiment of the present invention is realized. Hereinafter, a description will be given with reference to FIG.

  The game apparatus 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, an interface 104, a controller 105, an external memory 106, and a DVD (Digital Versatile Disk). ) -ROM drive 107, image processing unit 108, audio processing unit 109, and NIC (Network Interface Card) 110.

  Note that a DVD-ROM storing a game program and data is loaded into the DVD-ROM drive 107, and the game apparatus 100 is turned on to execute the program. Realized.

  The CPU 101 controls the overall operation of the game apparatus 100 and is connected to each component to exchange control signals and data.

  The ROM 102 records an IPL (Initial Program Loader) that is executed immediately after the power is turned on, and when this is executed, the program recorded on the DVD-ROM is read out to the RAM 103 and execution by the CPU 101 is started. The The ROM 102 stores an operating system program and various data necessary for operation control of the entire game apparatus 100.

  The RAM 103 is for temporarily storing data and programs, and holds programs and data read from the DVD-ROM and other data necessary for game progress and chat communication.

  The controller 105 connected via the interface 104 receives an operation input performed when the user executes the game. For example, the controller 105 accepts input of a character string (message) or the like according to the operation input.

  The external memory 106 detachably connected via the interface 104 stores data indicating the progress of the game, chat communication log (record) data, and the like in a rewritable manner. The user can record these data in the external memory 106 as appropriate by inputting an instruction via the controller 105.

  A DVD-ROM mounted on the DVD-ROM drive 107 stores a program for realizing the game and image data and sound data associated with the game. Under the control of the CPU 101, the DVD-ROM drive 107 performs a reading process on the DVD-ROM loaded therein, reads out necessary programs and data, and these are temporarily stored in the RAM 103 or the like.

  The image processing unit 108 processes the data read from the DVD-ROM by the CPU 101 or an image arithmetic processor (not shown) included in the image processing unit 108, and then processes the processed data on a frame memory ( (Not shown). The image information recorded in the frame memory is converted into a video signal at a predetermined synchronization timing and output to a monitor (not shown) connected to the image processing unit 108. Thereby, various image displays are possible.

The image calculation processor can execute a two-dimensional image overlay calculation, a transmission calculation such as α blending, and various saturation calculations at high speed.
In addition, the polygon information arranged in the virtual three-dimensional space and added with various kinds of texture information is rendered by the Z buffer method, and a rendered image is obtained by overlooking the polygon arranged in the virtual three-dimensional space from a predetermined viewpoint position. High speed execution of the obtained operation is also possible.

  Further, the CPU 101 and the image arithmetic processor operate in a coordinated manner, so that a character string can be drawn as a two-dimensional image in a frame memory or drawn on the surface of each polygon according to font information that defines the character shape. is there. The font information is recorded in the ROM 102, but it is also possible to use dedicated font information recorded in the DVD-ROM.

  The audio processing unit 109 converts audio data read from the DVD-ROM into an analog audio signal, and outputs the analog audio signal from a speaker (not shown) connected thereto. Further, under the control of the CPU 101, sound effects and music data to be generated during the progress of the game are generated, and sound corresponding to this is output from the speaker.

  The NIC 110 is for connecting the game apparatus 100 to a computer communication network (not shown) such as the Internet, and conforms to the 10BASE-T / 100BASE-T standard used when configuring a LAN (Local Area Network). Therefore, analog modems for connecting to the Internet using telephone lines, ISDN (Integrated Services Digital Network) modems, ADSL (Asymmetric Digital Subscriber Line) modems, cables for connecting to the Internet using cable television lines A modem or the like, and an interface (not shown) that mediates between them and the CPU 101 are configured.

In addition, the game apparatus 100 uses a large-capacity external storage device such as a hard disk so that the ROM 102, the RAM 103, the external memory 106, the DVD-ROM attached to the DVD-ROM drive 107, and the like function. It may be configured.
Further, it is possible to adopt a form in which a keyboard for accepting a character string editing input from a user, a mouse for accepting various position designations and selection inputs, and the like are connected.

  Further, instead of the game apparatus 100 of the present embodiment, a general computer (general-purpose personal computer or the like) can be used as an image generation apparatus. For example, a general computer, like the game apparatus 100, includes a CPU, RAM, ROM, DVD-ROM drive, and NIC, and an image processing unit that has simpler functions than the game apparatus 100. In addition to having a hard disk as an external storage device, a flexible disk, a magneto-optical disk, a magnetic tape, and the like can be used. In addition, a keyboard, a mouse or the like is used as an input device instead of a controller. Then, after the game program is installed, when the program is executed, it functions as an image generation device.

(Schematic configuration of the image generation device)
FIG. 2 is a schematic diagram illustrating a schematic configuration of the image generation apparatus according to the present embodiment. As an example, this image generation device is a device that generates a game image in an action game in which a character (self character) operated by a player can move while arbitrarily changing the direction of a game field in a three-dimensional virtual space. . Hereinafter, a description will be given with reference to FIG.

  The image generation apparatus 200 includes an object information storage unit 210, an operation reception unit 220, a position management unit 230, a mask image generation unit 240, a transparency calculation unit 250, and an image drawing unit 260.

First, the object information storage unit 210 stores information about objects such as the own character, enemy characters, trees, buildings, and light sources arranged in the three-dimensional virtual space. That is, information such as polygons, sprites, and texture images that constitute various objects appearing in the game is stored.
The light source object includes a sun object and the like as an example.
The RAM 103 or the like can function as such an object information storage unit 210.

The operation accepting unit 220 accepts an operation input such as an operation instruction from the player for the player character. For example, the operation reception unit 220 includes a plurality of buttons corresponding to operations such as moving in a predetermined direction, jumping, squatting, and lying down (for example, a direction key, an A button, a B button, and an X button arranged on the controller 105. , Y button, etc.) are pressed by the player to accept an operation input for the player character.
Note that the controller 105 can function as such an operation receiving unit 220.

The position management unit 230 manages the position of each object in the virtual space and viewpoint information.
For example, position information (current position, orientation, etc.) of an object whose position changes in the virtual space, such as its own character or enemy character, is managed. In other words, the position information of the player character is managed by the position management unit 230 because the position and orientation in the virtual space change according to the movement instruction received by the operation receiving unit 220. Further, since the enemy character also moves appropriately according to a predetermined logic and the position in the virtual space changes, the position information is similarly managed.
In addition, the position management unit 230 also manages position information (fixed values) of objects whose positions do not change in the virtual space, such as trees, buildings, and light sources (such as the sun). In addition, when a light source object such as the sun changes its position with the passage of time in the game, for example, position information that changes sequentially is managed.
Further, the position management unit 230 appropriately manages viewpoint information (current viewpoint position and orientation).
The RAM 103 and the CPU 101 can function as such a location management unit 230.

The mask image generation unit 240 generates a mask image used for dimming (decreasing brightness) the view field image excluding the light source object such as the sun (not including the light source object).
For example, the mask image generation unit 240 secures a mask buffer initialized in black, and when a light source object such as the sun enters the view (included in the view image), the sprite of the light source object Is drawn in the buffer.
More specifically, when the sun is located in the upper right of the field of view based on viewpoint information (position and direction) or the like, the mask image generation unit 240 uses a sun object Toj for the mask as shown in FIG. Draw in the buffer.
Then, based on the information in the buffer, the mask image generation unit 240 generates a mask image MK as shown in FIG. That is, a mask image is generated that is black as a whole and is cut out (cut out) only for the shape of the sun object (sun object after projection conversion).
Note that the mask image before the shape of the sun object is cut off is, for example, a rectangular shape having the same size as the projection-converted screen screen (that is, the entire field of view). As described later, transparency (opacity) ) Can be set as appropriate.
The RAM 103 and the CPU 101 can function as such a mask image generation unit 240.

Returning to FIG. 2, the transparency calculation unit 250 calculates the transparency (alpha value) of the mask image described above based on the arrangement state of the light source objects in the field of view.
For example, the transparency calculation unit 250 calculates the alpha value of the mask image based on the angle between the direction from the viewpoint to the light source object and the viewpoint direction, the shielding ratio of the light source object, and the like.
Specifically, as shown in FIG. 4A, the transparency calculation unit 250 calculates an alpha value based on an angle θ formed by the direction d1 from the viewpoint V to the sun object Toj and the line-of-sight direction d2.
As an example, the case where the alpha value range is 0.0 to 1.0, 0.0 is the highest transparency (completely transparent), and 1.0 is the lowest transparency (completely opaque) will be described. The transparency calculation unit 250 calculates the alpha value in the range of 0.0 to 1.0.
More specifically, the transparency calculation unit 250 approaches 1.0 as the angle θ decreases as shown in the graph of FIG. 4B in a state where the light source object is in the field of view. The alpha value is calculated so as to decrease, and conversely, the alpha value is calculated so as to approach 0.0 (transparency increases) as the angle θ increases. The graph shown in FIG. 4B is an example and can be changed as appropriate.
As shown in FIG. 4C, the sun object Toj on the projected screen screen Sc approaches the center Cn as the angle θ decreases, and conversely, the sun object Toj moves away from the center Cn as the angle θ increases. Therefore, the alpha value can also be calculated from the position of the sun object Toj with respect to the center Cn (as an example, the distance between the center Cn and the sun object Toj).

In addition, when a part of the light source object is shielded by another object or the like, the transparency calculation unit 250 corrects the alpha value according to the shielding ratio.
For example, when calculating the direction from the viewpoint to the light source object, the transparency calculation unit 250 detects the presence or absence of an object that shields between them, and if there is an object to be shielded, the shielding ratio (how much is being shielded) ) The method for obtaining the shielding ratio is arbitrary and can be applied as appropriate. For example, it may be determined whether or not the light source object is shielded after being projected on the screen screen by projection conversion, and if the light source object is shielded, the shielding ratio may be obtained.
In addition to being shielded by other objects, when a light source object is arranged at the edge of the field of view and a part of it is missing from the field of view, the part outside the field of view is similarly shielded. Shall be handled.
And the transparency calculation part 250 correct | amends the alpha value calculated according to the above-mentioned angle (theta) etc. according to the calculated | required shielding ratio. For example, as shown in the graph of FIG. 4D, a correction coefficient (0.0 to 1.0) corresponding to the shielding ratio is obtained, and the alpha value is corrected by multiplying the alpha value by this coefficient value. In other words, when the shielding ratio is small, the alpha value is corrected so that it is slightly lower (so that it is slightly transparent), and conversely, when the shielding ratio is large, the alpha value is corrected so that it is considerably low (very transparent) To be). The graph shown in FIG. 4D is an example and can be changed as appropriate.
That is, the transparency calculation unit 250 corrects the alpha value so that the alpha value becomes smaller as the shielding ratio increases (so that the alpha value becomes more transparent).

When the alpha value is calculated in this way, the transparency calculation unit 250 sets the calculated alpha value in the above-described mask image. As a result, the transparency of the mask image is determined.
As described above, since the mask image itself is black, the mask image is an image for synthesizing grays having different lightness levels according to the calculated (set) alpha value. As an example, as shown in the graph of FIG. 5A, when the transparency is small (alpha value is large), the color becomes dark (low brightness) gray, and conversely, when the transparency is large (alpha value is small), Light (high brightness) gray. The graph shown in FIG. 5A is an example and can be changed as appropriate.
A case where the light source object (sun object) is not shielded will be described as an example. When the angle θ is small and the light source object is close to the center, a dark (low brightness) gray mask image as shown in FIG. It becomes MK. Conversely, when the angle θ is large and the light source object is away from the center, a light (high brightness) gray mask image MK as shown in FIG. 5C is obtained.
The CPU 101 can function as such a transparency calculation unit 250.

Returning to FIG. 2, the image drawing unit 260 draws a display image (view image) based on the object in the view and the generated mask image.
For example, when the image drawing unit 260 identifies an object that falls within the field of view based on the position and viewpoint information of each object managed by the position management unit 230, a projection image obtained by projecting the object onto the screen screen by projection conversion is obtained. Generate. At this time, it is also determined whether or not the light source object is included in the field of view (whether the sun object or the like can be seen from the viewpoint).
When the light source object is included in the view, the image drawing unit 260 draws the view image by synthesizing the mask image with the projection image. As described above, since the alpha value is appropriately set in the mask image based on the angle θ or the like, a visual field image whose brightness is reduced (darkened) except for the light source object is obtained by this composition. Generated.

Specifically, as shown in FIG. 6A, the image drawing unit 260 combines the mask image MK from the viewpoint V side on the image G obtained by projecting the object in the field of view. Thereby, a display image HG as shown in FIG. 6B is generated.
In this display image HG, since the sun object Toj is left as it is, the brightness of the other objects is reduced (the lightness is drawn dimly), the brightness of the sun object Toj is relatively emphasized, and the sun object Toj is displayed to the player. You will feel more dazzling.
The image processing unit 108 can function as such an image drawing unit 260.

(Operation of image generation device)
FIG. 7 is a flowchart showing a flow of image generation processing executed in the image generation apparatus 200 having the above-described configuration. Hereinafter, the operation of the image generation apparatus 200 will be described with reference to FIG. For example, this image generation processing is repeatedly executed every drawing cycle (for example, every 1/60 seconds) during the execution of the game.

  First, the image generation device 200 identifies each object arranged in the field of view (step S301). That is, the image drawing unit 260 identifies each object that falls within the field of view based on the position and viewpoint information of each object managed by the position management unit 230.

  The image generating apparatus 200 draws the projection-converted image (Step S302). That is, the image drawing unit 260 generates a projection image in which each identified object is projected on the screen screen by projection conversion.

The image generating apparatus 200 determines whether there is a light source in the field of view (step S303). That is, it is determined whether or not a sun object or the like is visible from the viewpoint.
If the image generation apparatus 200 determines that there is no light source in the field of view (step S303; No), the image generation process ends. That is, the projection-converted image is directly used as a display image (view field image).

On the other hand, when it is determined that there is a light source in the field of view (step S303; Yes), the image generation device 200 draws the light source object in the buffer and generates a mask image (step S304).
That is, the mask image generation unit 240 draws the sprite of the light source object such as the sun in the mask buffer initialized in black. Then, based on the information in the buffer, the mask image generation unit 240 generates a mask image MK as shown in FIG. That is, a rectangular (substantially rectangular) mask image is generated that is entirely black and cut out only the shape of the light source object such as the sun.

The image generating apparatus 200 calculates an alpha value and sets it as a mask image (step S305).
That is, the transparency calculation unit 250 calculates the alpha value of the mask image based on the angle between the direction from the viewpoint to the light source object and the viewpoint direction, the shielding ratio of the light source object, and the like.
For example, as shown in FIG. 4A described above, the transparency calculation unit 250 calculates the alpha value based on the angle θ formed by the direction d1 from the viewpoint V to the sun object Toj and the line-of-sight direction d2. That is, as shown in the graph of FIG. 4B described above, the alpha value is calculated so as to approach 1.0 (become opaque) as the angle θ decreases, and conversely, as the angle θ increases, 0 increases. Calculate the alpha value so that it approaches 0 (becomes transparent).
In addition, when a part of the light source object is shielded, the transparency calculation unit 250 corrects the alpha value according to the shielding ratio.
For example, as shown in the graph of FIG. 4D described above, the transparency calculation unit 250 calculates a correction coefficient (0.0 to 1.0) corresponding to the shielding ratio, and multiplies the alpha value by this coefficient value. To correct the alpha value. In other words, the alpha value calculated based on the angle θ is corrected so that the alpha value becomes smaller as the shielding ratio increases (so that the alpha value becomes more transparent).
Then, the transparency calculation unit 250 sets the calculated alpha value in the mask image.

The image generating apparatus 200 synthesizes a mask image with the projection-converted image (Step S306).
That is, the image drawing unit 260 draws a display image (view image) by combining a mask image in which an alpha value is set with a projection image obtained by projecting an object in the view onto the screen screen.
For example, as illustrated in FIG. 6A described above, the image drawing unit 260 generates a display image by combining the projected image G with the mask image MK superimposed from the viewpoint V side. That is, the display image HG as shown in FIG.

By such an image generation process, when a light source object such as the sun enters the field of view, a display image (view field image) with other lightness is drawn without changing the light source object. At that time, the lightness (darkness) differs depending on the position of the light source object with respect to the line of sight.
That is, when the light source object is away from the line-of-sight direction (the center of the field-of-view image), a slightly dim view image as shown in FIG. 8A is generated, and when the light source object is close to the line-of-sight direction, FIG. A fairly dark view image as shown in b) is generated.
8A and 8B, the brightness of the light source object is relatively emphasized because the brightness of the light source object (the sun object) is left as it is and the other lightness is reduced. The light source object feels more dazzling for the player.

  As a result, the glare of the light source can be appropriately expressed.

(Other embodiments)
In the above embodiment, the case where the alpha value of the mask image is calculated based on the arrangement state (arrangement position and shielding ratio) of the light source object in the field of view has been described.
In order to further improve the reality, it may be expressed that the eyes gradually get used as the light source object continues to be displayed.
Hereinafter, other embodiments that can further enhance the reality will be described below with reference to the drawings.

FIG. 9 is a schematic diagram showing a schematic configuration of an image generation apparatus 400 according to another embodiment of the present invention.
As shown in the figure, the image generation device 400 includes an object information storage unit 210, an operation reception unit 220, a position management unit 230, a mask image generation unit 240, a transparency calculation unit 250, an image drawing unit 260, and a timekeeping. Part 410.
The image generating apparatus 400 is obtained by adding a time measuring unit 410 to the configuration of the image generating apparatus 200 of FIG. 2 described above. That is, the configuration of the object information storage unit 210 to the image drawing unit 260 is the same as that of the image generation device 200.

The time measuring unit 410 measures the elapsed time after the light source object enters the field of view.
For example, the timing unit 410 has the light source object located in the field of view (the light source object is visible from the viewpoint) based on the relationship between the position of the light source object managed by the position management unit 230 and the viewpoint information (position and direction). ), And the elapsed time is counted up while the light source object is located in the field of view.
Note that the timer unit 410 clears the elapsed time to zero when the light source object is out of the field of view.

The transparency calculation unit 250 calculates the alpha value of the mask image in consideration of the elapsed time measured by the timer unit 410.
For example, as described above, after calculating the alpha value based on the arrangement state of the light source object in the field of view, correction is performed so that the alpha value decreases (increases transparency) according to the value of the elapsed time. To do.
Specifically, as shown in the graph of FIG. 10, the attenuation coefficient value (0.0 to 1.0) corresponding to the elapsed time is sequentially obtained, and the alpha value is calculated by multiplying the alpha value by the coefficient value. Decrease with time. The graph shown in FIG. 10 is an example and can be changed as appropriate.
In other words, as the time passes, the brightness of the view image gradually increases (so that it becomes brighter). In short, the longer the elapsed time, the smaller the alpha value (so that the transparency becomes larger) To) to correct.

Hereinafter, the flow of image generation processing executed in the image generation apparatus 400 having such a configuration will be described with reference to the flowchart of FIG.
Note that the same reference numerals are added to the same portions as those in the image generation processing of FIG. 7 described above. In addition, this image generation processing is also repeatedly executed at every drawing cycle (for example, every 1/60 seconds) during game execution.

First, the image generating apparatus 400 identifies each object arranged in the field of view (step S301), and draws a projection-converted image (step S302). That is, the image drawing unit 260 identifies each object in the field of view, and generates a projection image in which each identified object is projected on the screen screen by projection conversion.
The image generating apparatus 400 determines whether there is a light source in the field of view (step S303). That is, it is determined whether or not a sun object or the like is visible from the viewpoint.

When determining that there is no light source in the field of view (step S303; No), the image generating apparatus 400 clears the elapsed time (step S501).
That is, the time measuring unit 410 clears the elapsed time that has been counted to zero.
Then, the image generation device 400 ends the image generation process. That is, the projected image is used as it is as a display image.

On the other hand, when it is determined that there is a light source in the field of view (step S303; Yes), the image generating apparatus 400 determines whether or not the elapsed time exceeds the reference value (step S502).
When determining that the elapsed time exceeds the reference value (step S502; Yes), the image generation apparatus 400 ends the image generation process. That is, when the time has passed so that the brightness of the view field image does not need to be lowered, the projection-converted image is directly used as the display image.

  On the other hand, when it is determined that the elapsed time does not exceed the reference value (step S502; No), the image generation device 400 draws the light source object in the buffer and generates a mask image (step S304). That is, a mask image as shown in FIG.

The image generation apparatus 400 calculates the alpha value while taking into account the elapsed time, and sets it as a mask image (step S503).
That is, the transparency calculation unit 250 first calculates the alpha value of the mask image based on the angle between the direction from the viewpoint to the light source object and the viewpoint direction, the shielding ratio of the light source object, and the like.
Thereafter, the transparency calculation unit 250 corrects the alpha value to be small (so that the transparency is large) according to the value of the elapsed time.
That is, as shown in the graph of FIG. 10 described above, the transparency calculation unit 250 obtains an attenuation coefficient (0.0 to 1.0) corresponding to the elapsed time, and multiplies the alpha value by this coefficient value. Correct the value. As a result, the alpha value is corrected so as to decrease as the elapsed time increases (so that the transparency increases).

  The image generation apparatus 400 synthesizes a mask image with the projection-converted image (step S306). That is, the image drawing unit 260 draws a display image (field-of-view image) by synthesizing a mask image in which an alpha value is set with the projection-converted image.

  Then, after adding the elapsed time (step S504), the image generation device 400 ends the image generation process.

By such image generation processing, as the elapsed time increases, the brightness of the field-of-view image gradually increases (becomes brighter).
For example, in a scene where a light source object (sun object) is near the center of the field of view, if the elapsed time is small, a considerably dark field of view image is drawn as shown in FIG. Then, when the time passes as it is (the elapsed time increases), as shown in FIG. 12B, a dim view image is drawn (the darkness gradually decreases). Further, as time elapses (when the elapsed time exceeds the reference value), a view field image that does not synthesize the mask image is drawn, as shown in FIG.
For this reason, even if a dark visual field image is initially drawn, the darkness gradually becomes lighter as time elapses, so that the player's eyes can be felt as they are getting used to it.
As a result, the glare of the light source can be expressed with higher reality.

  As described above, according to the present invention, the glare of the light source can be appropriately expressed.

It is a mimetic diagram showing an outline composition of a game device in this embodiment. It is a schematic diagram which shows an example of a structure of the image generation apparatus in this embodiment. (A), (b) is a schematic diagram for demonstrating the shape of a mask image. (A) is a schematic diagram for demonstrating each angle (theta) which the direction to a sun object and a gaze direction make, (b) is a graph which shows the relationship between angle (theta) and an alpha value, (c) is. It is a schematic diagram for demonstrating the screen object and the projected sun object, (d) is a graph which shows the relationship between a shielding ratio and a correction coefficient. (A) is a graph which shows the relationship between the transparency (alpha value) and brightness of a mask image, (b), (c) is a schematic diagram for demonstrating the mask image to which the alpha value was set. (A), (b) is a schematic diagram for demonstrating a mode that a mask image is synthesize | combined with a projection image. It is a flowchart which shows the flow of the image generation process in this embodiment. (A), (b) is a schematic diagram for demonstrating a mode that the brightness of a visual field image changes according to the position of the sun object in a visual field. It is a schematic diagram which shows an example of a structure of the image generation apparatus in other embodiment. It is a graph which shows the relationship between elapsed time and an attenuation coefficient. It is a flowchart which shows the flow of the image generation process in other embodiment. (A)-(c) is a schematic diagram for demonstrating a scene image becoming bright as time passes.

Explanation of symbols

100 game machine 101 CPU
102 ROM
103 RAM
104 Interface 105 Controller 106 External Memory 107 DVD-ROM Drive 108 Image Processing Unit 109 Audio Processing Unit 110 NIC
200, 400 Image generation device 210 Object information storage unit 220 Operation reception unit 230 Position management unit 240 Mask image generation unit 250 Transparency calculation unit 260 Image drawing unit 410 Timekeeping unit

Claims (8)

An image generation device that generates a view field image in which a virtual space where a plurality of objects including a light source object are arranged is viewed from a predetermined viewpoint,
An adjustment image generation unit that generates an adjustment image of a shape in which the light source object is cut out when the light source object is included in the field of view ;
When the light source object is included in the field of view , a calculation unit that calculates the brightness to be adjusted lower by the adjustment image based on the arrangement state of the light source object with respect to the center of the field of view,
Generating a projection image of each object is positioned within the field of view, when the light source object is included within the field of view, by synthesizing the corresponding adjusted image to which the projected image and the brightness is adjusted, except for the light source object An image drawing unit for drawing a field-of-view image with reduced brightness ,
An image generation apparatus characterized by that. An image generation device that generates a view field image in which a virtual space where a plurality of objects including a light source object are arranged is viewed from a predetermined viewpoint,
If the source object is included in the field of view, a mask image generation unit which generates a mask image of the reference and to shape the light source object were cut from view entirely and the viewpoint,
When the light source object is included in the field of view , a calculation unit that calculates the transparency for setting the mask image based on the arrangement state of the light source object with reference to the center of the field of view,
Each object that is placed within the field of view to generate a projection image obtained by projection transformation, when the light source object is included within the field of view, by synthesizing the corresponding mask image in which the projected image and the transparency is set, the light source An image drawing unit that draws a field-of-view image with reduced brightness, excluding objects ,
An image generation apparatus characterized by that. An image generating apparatus according to claim 2,
The mask image generation unit generates a mask image of the same amount corresponding to the project the light objects from the rectangular shape of the black in size were cut shape as screen display used for the projection,
The calculation unit calculates the transparency as the arrangement of the light source object is closer to the center of the field of view, and conversely calculates the transparency as the arrangement of the light source object is far from the center of the field of view,
The image drawing unit combines a projection image obtained by projecting each object arranged in the field of view onto the screen screen and a black mask image set with the calculated transparency, and removes the light source object. , Draw a field-of-view image with the entire darkness,
An image generation apparatus characterized by that. The image generation device according to claim 2 or 3,
The calculation unit calculates transparency based on an angle formed by a direction from a viewpoint to a light source object and a line-of-sight direction.
An image generation apparatus characterized by that. The image generation apparatus according to claim 4,
The calculation unit corrects the calculated transparency based on a blocking ratio indicating a blocking ratio when the light source object is blocked by another object.
An image generation apparatus characterized by that. The image generation device according to any one of claims 2 to 5,
It further comprises a timekeeping unit that times the elapsed time when the light source object is arranged in the field of view,
The calculation unit sequentially increases the transparency as the elapsed time counted increases.
An image generation apparatus characterized by that. An image in an image generation device that has an adjustment image generation unit, a calculation unit, and an image drawing unit, and generates a view field image in which a virtual space in which a plurality of objects including a light source object are arranged is viewed from a predetermined viewpoint A generation method,
An adjustment image generation step for generating an adjustment image of a shape in which the light source object is cut out when the adjustment image generation unit is included in the field of view ;
A calculation step in which the calculation unit calculates the brightness to be adjusted to be lower by the adjustment image when the light source object is included in the field of view based on the arrangement state of the light source object based on the center of the field of view;
The image rendering unit generates a projected image of each object is positioned within the field of view, when the light source object is included within the field of view, by synthesizing the corresponding adjusted image to which the projected image and the brightness is adjusted An image drawing step for drawing a field-of-view image with reduced brightness, excluding the light source object ,
An image generation method characterized by the above. Computer
An adjustment image generation unit that generates an adjustment image of a shape in which the light source object is cut out when the light source object is included in the field of view ;
When the light source object is included in the field of view , a calculation unit that calculates the brightness to be adjusted lower by the adjustment image based on the arrangement state of the light source object with respect to the center of the field of view,
Generating a projection image of each object is positioned within the field of view, when the light source object is included within the field of view, by synthesizing the corresponding adjusted image to which the projected image and the brightness is adjusted, except for the light source object , An image drawing unit that draws a field of view image with reduced brightness ,
A program characterized by functioning as

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