JP4549415B2 - Image generation method, image generation apparatus, and recording medium storing image generation program - Google Patents

Description

  The present invention relates to image generation using a computer, and more particularly to three-dimensional image generation on a game screen.

  In recent years, a three-dimensional image is often displayed on a game screen in a game using a computer. In this three-dimensional image display, an object to be displayed is held in a memory as three-dimensional information. From this stored three-dimensional information, a viewpoint is set at one point of three-dimensional coordinates, and an image of a target object viewed from the position of this viewpoint is displayed on a display. As described above, image generation processing is performed separately for “modeling” for creating three-dimensional information and “rendering” for displaying. According to this method, an arbitrary three-dimensional world can be simulated by manipulating the three-dimensional information, and the simulated world can be freely displayed. Even from a position that cannot be seen in reality, it is possible to set the viewpoint position freely.

  In such image generation, for example, a car hits a display target object such as a situation where a car enters a tunnel dotted with lights and a window through which light from the outside enters the tunnel is vacant. Sometimes you want to display a scene where the light changes. In this case, the display is usually performed by changing the parameter for the light source at the time of display (see, for example, JP-A-7-155464).

  The present invention does not change the parameters of a conventional light source, but generates an image that can represent and display changes in the appearance of an object when brightness or the like changes due to a change in the situation, using a different technique. Is to provide.

To achieve the above object, the present invention is an image generating method for generating a 3-dimensional image, 3-dimensional detecting a change in status of the display object in the image, detection of a change in status of said display object is wet depending on the display the direction of the reflecting surface of the object is changed by bump mapping, based on the changed reflection, the display object is characterized by displaying as wet water droplets.
The change of the situation can also be performed by detecting the position of the display object.
An apparatus for realizing the above-described method and a recording medium storing an image generation program for causing a computer to execute the above-described method are also the present invention.
With this configuration, it is possible to express and display a change in the appearance of an object due to a change in the situation in which the display object is wet .

The present invention expresses a change in the appearance of an object when the brightness or the like changes due to a change in the situation, by changing the reflection instead of changing the parameters of the conventional light source.
Therefore, instead of changing the light source, it can be set for each individual display target object by displaying with the change in reflection of the display target itself, so various settings can be made for each individual object. And display according to changes in various situations.

  An embodiment of the present invention will be described with reference to a display of a game or the like performed using a computer. This will be described in detail with reference to the drawings.

  First, FIG. 1 shows a system configuration example used in the game of the embodiment. In FIG. 1, a CPU 102 controls the overall processing of this game system. The input interface 104 is an interface for inputting operation inputs such as an accelerator and a handle from an input device (not shown) to a driving game, for example, to the game system. The sound device 106 generates music and sound effects under the control of the CPU 102 and outputs them from a speaker (not shown). The ROM 108 and RAM 110 store programs and data used by the CPU 102, the geometry processing device 112, and the like.

  The CPU 102 stores, in the polygon data memory 114, polygon data corresponding to three-dimensional information such as the position information of the car operated by the player. The geometry processing device 112 reads the polygon data stored in the polygon data memory 114 and performs a three-dimensional coordinate conversion process. Conversion processing for display is performed from the three-dimensional data subjected to the coordinate conversion processing, and the drawing device 116 stores the result in the frame memory 118. Then, image data to be displayed is read from the frame memory 118 and sent to a display device (not shown) to display a game.

  In the game machine having such a configuration, the polygon data memory 114 stores the result of simulating an arbitrary three-dimensional world by operating the above-described three-dimensional information. Then, the data is read out by the geometry processing unit 112, rendering processing is performed to form image data to be displayed, and the image data is stored in the frame memory 118. In forming this image data, for example, there is a ray tracing method. This is a technique for generating a viewpoint for each pixel of image data to be displayed, obtaining intersections of all display target objects and lines of sight, and forming image data to be displayed. At this time, it is necessary to calculate the luminance of the intersection of the display target object and the viewpoint. To calculate the brightness, examine the object that intersects the line connecting the light source and the intersection, calculate the presence or absence of shadows, and calculate the final brightness using the reflectance of the surface of the intersecting object. .

  This ray tracing can express an image by direct light, but an image by indirect light can be expressed by a technique called a radiosity method, for example. This is also calculated using the reflectance of the display object. For these methods, for example, refer to publications such as “CG Standard Textbook for Computer Graphics / Technology” (issued by the 5th edition of May 1996).

In the present invention, the change of the appearance due to the change of the situation is performed by changing the reflection of the surface of the object when creating the image data of the display target object.
This will be specifically described with reference to FIGS.

  FIG. 2 illustrates a display when, for example, a display target object enters a tunnel and a light source is blocked. In this case, by changing the reflectance of the surface of the display target object due to a change in the situation of entering the tunnel, the object that enters the shadowed part by the light ray being blocked can be displayed.

  FIG. 3 shows a case where an object illuminated by, for example, sunset is expressed. In this case, the reflectance of the surface of the display target object is made to reflect a lot of red light components due to a change in the situation due to the sunset time. As a result, the display target object looks like a red light such as sunset.

  As described above, in the present invention, since the conventional light source is not changed but the reflection of the display object itself is changed, it can be set for each individual display object. Various settings can be made for each object.

  For example, as shown in FIG. 4, even when the display target object is wetted by water droplets due to condensation or water droplets near the waterfall, it can be expressed by the method of changing the reflection of the present invention. That is, using a method called bump mapping that controls the direction of reflection on the surface of an object, it can be expressed as if water droplets were attached to the surface. For this bump mapping, please refer to the above-mentioned “CG Standard Textbook for Computer Graphics and Technology” (issued by the 5th edition of May 1996).

  Processing for displaying these will be described with reference to the flowcharts shown in FIGS.

FIG. 5 is a flowchart showing a process of changing the reflectance of the display object according to the change of the situation as described in FIG. FIG. 5 shows the case where the change in situation depends on the position. In this case, first, the position of the display object is calculated (S502). When the position of the display object is a position where the reflectance is changed (YES in S504), the reflectance is changed based on this position (S506). This is the case, for example, when the display object enters a tunnel and the light source that irradiates the object changes, and the appearance of the display object changes. In this case, it is detected that the tunnel has been entered according to the position. The change in the reflectance of the display object may be changed by calculation or may be set to a predetermined reflectance depending on the situation. Thereafter, the display object is displayed using the changed reflectance (S508).
In the position detection of the display object, when the reflectance is not changed (NO in S504), the display object is displayed as it is (S510).

FIG. 6 is a flowchart for explaining processing for changing the color of the display target object as shown in FIG. In FIG. 6, as in FIG. 5, the position of the display object is calculated (S602). When the calculated position of the display object is a position where the reflectance is changed due to a change in the situation (YES in S604), the reflectance is changed based on this position. In this process, the reflectance of each of the three primary colors of light of R (red), G (green), and B (blue) is changed (S606 to S610). Then, display is performed by reflecting the change in reflectance for each color (S612). In this way, for example, it can be expressed that it is illuminated by the sunset.
In the position detection of the display object, when the reflectance is not changed (NO in S604), the display object is displayed as it is (S614).

As shown in FIG. 4, the bump mapping of the display object can be changed according to the change of the situation by the same processing as in FIGS. 5 and 6.
In FIG. 5 and FIG. 6, the change in the situation is detected by detecting the position, but the change in the situation may be detected by, for example, the time in the game.

  In this way, since the reflectance of the display target object itself is displayed instead of changing the conventional light source, it can be set for each individual display target object. Settings can be made.

  The configuration of the present invention can be realized by reading and executing the program from the storage medium storing the program related to the present invention. Examples of the recording medium include a flexible disk, a CD-ROM, a magnetic tape, and a ROM cassette.

It is a block diagram which shows the system configuration which embodiment uses. It is a figure which shows the example of application of this invention. It is a figure which shows the example of application of this invention. It is a figure which shows the example of application of this invention. It is a flowchart which shows the process of embodiment. It is a flowchart which shows the process of other embodiment.

Explanation of symbols

102 CPU
104 Input interface 106 Sound device 108 ROM
110 RAM
112 Geometry processor 114 Polygon data memory 116 Drawing device 118 Frame memory

Claims (5)

In an image generation method for generating a three-dimensional image,
Detecting changes in the status of the display object in the 3D image;
In response to detection of a change in the situation where the display object is wet, the direction of reflection on the surface of the display object is changed by bump mapping,
An image generation method, comprising: displaying the display object as if wetted with water droplets based on the changed reflection. The image generation method according to claim 1,
An image generation method, wherein the change of the situation is performed by detecting the position of the display object. In an image generation apparatus that generates a three-dimensional image,
Detecting means for detecting a change in the state of the display object in the three-dimensional image;
Means for changing the direction of reflection of the surface of the display object by means of bump mapping in response to detection of a change in the situation in which the display object is wet ;
Based on the changed reflection, an image generating apparatus, characterized in that said display object and means for displaying as wet water droplets. The image generation apparatus according to claim 3 .
The image generation apparatus according to claim 1, wherein the detecting unit changes the situation by detecting a position of the display object. Recording medium storing an image generation program for executing the image generation method according to the computer to claim 1 or 2.

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