Image synthesizing system and game playing apparatus using the same

I claim:

1. An image synthesizing system comprising:

3-D space processing means for perspectively projecting a 3-D object onto a projection plane of a view point coordinate system from a view point, the 3-D object representing a shape model of a plurality of shape models, the shape model being formed by a combination of polygons in a virtual 3-D space;

texture information storage means for previously storing texture information relating to images on the polygons of said 3-D object; and

image forming means coupled to the 3-D space processing means and the texture information storage means for reading said texture information corresponding to the polygons of said perspectively projected 3-D object from said texture information storage means by mapping said texture information onto the polygons for forming and displaying an image on a display,

said 3-D space processing means comprising:

an object data storage unit for storing object data of said 3-D object, said object data being represented by the plurality of shape models having different degrees of precision;

an object data reading unit coupled to said object data storage unit for selecting a series of said object data of increasing degrees of precision as said 3-D object and said view point draw closer to each other, and for reading said object data from said object data storage unit; and

a 3-D calculation unit coupled to said object data reading unit for positioning in the virtual 3-D space the object data read from the object data storage unit and corresponding to said 3-D object, and for perspectively projecting said 3-D object onto the projection plane of the view-point coordinate system,

said texture information storage means storing the texture information of each of the polygons, the polygons forming respective members of the plurality of shape models based on different degrees of precision of said 3-D object, and

said image forming means for reading from said texture information storage means the texture information of the polygons forming the shape model of the plurality of shape models, the shape model having a precision corresponding to the polygons of said perspectively projected 3-D object, said image forming means synthesizing the image to be displayed by mapping said texture information onto the polygons.

2. An image synthesizing system as defined in claim 1, wherein said texture information storage means stores highly resolute texture information for the polygons in an image part requiring high resolution and a high precision shape model.

3. An image synthesizing system as defined in claim 1, wherein said texture information storage means stores highly resolute texture information for the polygons in an image part requiring high resolution.

4. An image synthesizing system as defined in claim 1, wherein said object data storage unit forms and stores an image part requiring high resolution for the shape model of high precision as independent polygons, and wherein said texture information storage means stores highly resolute texture information for the polygons in an image part requiring high resolution.

5. An image synthesizing system as defined in claim 1, wherein said object data storage unit stores a predetermined 3-D object as object data represented by the plurality of shape models for close-up, middle-range and long-shot modes, and wherein said texture information storage means stores highly resolute texture information for the polygons in an image part requiring high resolution of a close-up shape model of the plurality of shape models.

6. An image synthesizing system as defined in claim 1, wherein said object data includes vertex texture coordinates for each vertex of the polygons of said shape model, and wherein said image forming means calculates texture coordinates based on the vertex, the texture coordinates being used as texture information read-out addresses for all dots in the polygons, the calculated texture coordinates being used as addresses to read the texture information from said texture information storage means, and the image forming means forming and displaying the image by mapping the texture information read from the texture information storage means onto a corresponding polygon of the polygons.

7. An image synthesizing system as defined in claim 2, wherein said object data includes vertex texture coordinates for each vertex of the polygons of said shape model, and wherein said image forming means calculates texture coordinates based on the vertex, the texture coordinates being used as texture information read-out addresses for all dots in the polygons, the calculated texture coordinates being used as addresses to read the texture information from said texture information storage means, and the image forming means forming and displaying the image by mapping the texture information read from the texture information storage means onto a corresponding one of the polygons.

8. An image synthesizing system as defined in claim 3, wherein said object data includes vertex texture coordinates for each vertex of the polygons of said shape model, and wherein said image forming means calculates texture coordinates based on the vertex the texture coordinates, the texture coordinates being used as texture information read-out addresses for all dots in the polygons, the calculated texture coordinates being used as addresses to read the texture information from said texture information storage means, and the image forming means forming and displaying the image by mapping the texture information read from the texture information storage means onto a corresponding one of the polygons.

9. An image synthesizing system as defined in claim 5, wherein said object data includes vertex texture coordinates for each vertex of the polygons of said shape model, and wherein said image forming means calculates texture coordinates based on the vertex texture coordinates, the texture coordinates being used as texture information read-out addresses for all dots in the polygons, the calculated texture coordinates being used as addresses to read the texture information from said texture information storage means, and the image forming means forming and displaying the image by mapping the texture information read from the texture information storage means onto a corresponding one of the polygons.

10. A game playing apparatus comprising:

a player's control unit; and

an image synthesizing system responsive to input signals from said player's control unit and to a given game program for forming and displaying a game image on a display,

said image synthesizing system comprising:

3-D space processing means for perspectively projecting a 3-D object onto a projection plane of a view point coordinate system from a viewpoint, the 3-D object representing a shape model of a plurality of shape models formed by a combination of polygons in a virtual 3-D space;

texture information storage means for previously storing texture information relating to images on the polygons of said 3-D object; and

image forming means coupled to the 3-D space processing means and the texture information storage means for reading said texture information corresponding to the polygons of said perspectively projected 3-D object from said texture information storage means by mapping the texture information onto the polygons for forming and displaying the game image on the display,

said 3-D space processing means comprising:

an object data storage unit for storing object data of said 3-D object, said object data being represented by the plurality of shape models having different degrees of precision;

an object data reading unit coupled to said object data storage unit for selecting a series of said object data of increasing degrees of precision as said 3-D object and said view point draw closer to each other, and for reading said object data from said object data storage unit; and

a 3-D calculation unit coupled to said object data reading unit that responds to the input signals from the player's control unit and to the given game program for calculating a predetermined game, for controlling said object data reading unit to read said object data, for positioning in the virtual 3-D space the 3-D object by positioning the object data read from the object storage unit and for perspectively projecting said 3-D object onto the projection plane of the view-point coordinate system, the object data being read from the object data storage unit and corresponding to said 3-D object,

said texture information storage means storing the texture information of each of the polygons, the polygons forming respective members of the plurality of shape models based on different degrees of precision of said 3-D object, and

said image forming means for reading the texture information from said texture information storage means, the texture information corresponding to the polygons that form the shape model of the plurality of shape models, the shape model having a precision corresponding to the polygons of said perspectively projected 3-D object, said image forming means synthesizing the game image to be displayed by mapping said texture information onto the polygons.

11. A game playing apparatus as defined in claim 10, wherein said texture information storage means stores highly resolute texture information for the polygons in an image part requiring high resolution and a high precision shape model.

12. A game playing apparatus as defined in claim 10, wherein said texture information storage means stores highly resolute texture information for the polygons in an image part requiring high resolution.

13. A game playing apparatus as defined in claim 10, wherein said object data storage unit forms and stores an image part requiring high resolution for a high precision shape model as independent polygons, and wherein said texture information storage means stores highly resolute texture information for the polygons in the image part requiring high resolution.

14. A game playing apparatus as defined in claim 10, wherein said object data storage unit stores a predetermined 3-D object as object data represented by the plurality of shape models for close-up, middle-range and long-shot modes, and wherein said texture information storage means stores highly resolute texture information for the polygons in an image part requiring high resolution of a close-up shape model of the plurality of shape models.

15. A game playing apparatus as defined in claim 10, wherein said object data includes vertex texture coordinates for each vertex of the polygons of said shape model, and wherein said image forming means calculates texture coordinates based on the vertex texture coordinates, the texture coordinates being used as texture information read-out addresses for all dots in the polygons, the calculated texture coordinates being used as addresses to read the texture information from said texture information storage means, and the image forming means forming and displaying the game image by mapping the texture information read from the texture information storage means onto a corresponding one of the polygons.

16. A game playing apparatus as defined in claim 11, wherein said object data includes vertex texture coordinates for each vertex of the polygons of said shape model, and wherein said image forming means calculates texture coordinates based on the vertex texture coordinates, the texture coordinates being used as texture information read-out addresses for all dots in the polygons, the calculated texture coordinates being used as addresses to read the texture information from said texture information storage means, and the image forming means forming and displaying the game image by mapping the texture information read from the texture information storage means onto a corresponding one of the polygons.

17. A game playing apparatus as defined in claim 12, wherein said object data includes vertex texture coordinates for each vertex of the polygons of said shape model, and wherein said image forming means calculates texture coordinates based on the vertex texture coordinates, the texture coordinates being used as texture information read-out addresses for all dots in the polygons, the calculated texture coordinates being used as addresses to read the texture information from said texture information storage means, and the image forming means forming and displaying the game image by mapping the texture information read from the texture information storage means onto a corresponding one of the polygons.

18. A game playing apparatus as defined in claim 14, wherein said object data includes vertex texture coordinates for each vertex of the polygons of said shape model, and wherein said image forming means calculates texture coordinates based on the vertex texture coordinates, the texture coordinates being used as texture information read-out addresses for all dots in the polygons, the calculated texture coordinates being used as addresses to read the texture information from said texture information storage means, and the image forming means forming and displaying the game image by mapping the texture information read from the texture information storage means onto a corresponding one of the polygons.

Description Submit all comments and votes

TECHNICAL FIELD

The present invention relates to an image synthesizing system using the texture mapping technique and a game playing apparatus using such an image synthesizing system.

BACKGROUND ART

Conventionally, an image synthesizing system for synthesizing a pseudo three-dimensional (3-D) image through a computer graphic technique is known. Such an image synthesizing system is broadly used as in various video games, airplane and other vehicle maneuvering simulators.

FIG. 12 shows the principle of such an image synthesizing system. The image synthesizing system previously stores image information relating to a 3-D object 310 in a virtual 3-D space 300. The image information relating to the 3-D object 310 previously stored in a memory as a shape model comprises a plurality of polygons (1) to (6) (polygons (4) to (6) are not shown).

If the image synthesizing system is used in a driving game, the 3-D object 310 may be in the form of a racing car which moves in the virtual 3-D space 300 while competing with a player's car or in the form of a stationary matter such as a road, house or the like which is disposed in the virtual 3-D space.

When a steering wheel or the like in a control panel 314 is maneuvered by a player 312, the view point of a driver (player) which is set in the virtual 3-D space 300 corresponding to the player's car is varied in position and direction. 3-D objects representing the racing car competing with the player's car and the surrounding matters are perspectively projected on a perspective projection screen 316 of view-point coordinate system and displayed as a pseudo 3-D image 318. Thus, the 3-D objects including the racing car and other matters can be rotated and translated in real time by the player 312 to perform a simulation in the virtual 3-D space while viewing it from the driver (player).

There is also known an improved image synthesizing system using a so-called texture mapping technique. As shown in FIG. 3, such an image synthesizing system separates image information relating to a 3-D object 310 represented as a shape model which comprises in combination with a plurality of polygons and graphic information to be applied to the polygons forming the shape model (hereinafter called "texture information") and stores the shape model and the graphic information. When an image is output, texture data 340, 342 are applied to the respective polygons to synthesize the image.

According to such a texture mapping technique, the patterns and colors of a graphic can be processed intricately without increasing the number of polygons to be processed.

It is desirable that such a real-time display type image synthesizing system can synthesize a high-quality image while reducing the burden on the hardware.

However, the image synthesizing system of the prior art has the following problems.

First Problem

As for the image synthesizing system of the prior art, if the quality of a graphic is to be improved, the amount of data processed by the hardware increases, and the number of objects displayed per scene is limited.

In the driving game, for example, vehicles running on a road, buildings arranged along the road and other scenery may be displayed as 3-D objects. Each of these 3-D objects is formed as a shape model which comprises in combination with a plurality of polygons. To increase the reality in the 3-D objects, the shape model must be represented by more combinations of polygons.

In the computer graphics, however, the processing of polygons provides very high burden on the hardware. Therefore, as the number of polygons required to form one 3-D object multiplies, the burden on the hardware also increases. In displaying the image in real time, number of display objects per scene is so limited that the game scene can end up being monotonous.

Second Problem

In the driving game, a 3-D object may be enlarged partially and displayed as when a car approaches to another car.

In such a case, if the texture data applied to the polygons have normal resolution, the enlarged display 3-D object is extremely degraded, and the reality in the game scene is damaged.

If the texture information for the enlarged display 3-D object has high resolution, the memory capacity for storing the texture data becomes too big, making the entire system costly.

For example, on improving the quality of enlarged display image in an image synthesizing system capable of displaying a racing car on a circuit from various angles, the shape model of a 3-D object representing the racing car must first be formed by a number of polygons and the high-resolution texture information for the polygons is prepared and stored in a memory. This rises the manufacturing cost of the entire system, resulting in an unreasonably expensive image synthesizer for game playing machines.

In view of such problems, an object of the present invention is to provide an image synthesizing system which can form and display a 3-D object with less polygons of high resolution and a game playing apparatus using such an image synthesizing system.

DISCLOSURE OF THE INVENTION

To this end, the present invention provides an image synthesizing system comprising:

3-D space processing means for perspectively projecting a 3-D object representing a shape model formed by a combination of polygons in a virtual 3-D space onto a projection plane of view-point coordinate system;

texture information storage means for previously storing texture information relating to images on the polygons of said 3-D object; and

image forming means for reading texture information corresponding to the polygons of said perspectively projected 3-D object from said texture information storage means by mapping said texture information onto the polygons for forming and displaying an image on a display,

said 3-D space processing means comprising:

an object data storage unit for storing data of said 3-D object as object data represented by a plurality of shape models having different degrees of precision;

an object data reading unit for selecting object data of a shape model of higher precision as said 3-D object and a view point draw closer to each other and for reading said object data from said object data storage unit; and

a 3-D calculation unit for positioning the read 3-D object in a virtual 3-D space and perspectively projecting said 3-D object onto the projection plane of view-point coordinate system,

said texture information storage means for storing texture information of each polygon forming respective shape models of different precision based on said shape models having different degrees of precision of said 3-D object, and

said image forming means for reading texture information of a shape model of precision corresponding to the polygons of said perspectively projected 3-D object from said texture information storage means by mapping said texture information onto the polygons for synthesizing an image to be displayed.

The present invention also provides a game playing apparatus comprising:

a player's control unit; and

an image synthesizing system responsive to input signals from said player's control unit and to a given game program for forming and displaying a game image on a display,

said image synthesizing system comprising:

3-D space processing means for perspectively projecting a 3-D object representing a shape model formed by a combination of polygons in a virtual 3-D space onto a projection plane of view-point coordinate system;

texture information storage means for previously storing texture information relating to images on the; polygons of said 3-D object; and

image forming means for reading texture information corresponding to the polygons of said perspectively projected 3-D object from said texture information storage means by mapping the texture information onto the polygons for forming and displaying an image on a display,

said 3-D space processing means comprising:

an object data storage unit for storing data of said 3-D object as object data represented by a plurality of shape models having different degrees of precision;

an object data reading unit for selecting object data of a shape model of higher precision as said 3-D object and a view point draw closer to each other and for reading said object data from said object data storage unit; and

a 3-D calculation unit responsive to the input signals from the player's control unit and to the given game program for calculating a predetermined game and controlling said object data reading unit to read said object data, said 3-D calculation unit being further operative to position the read 3-D object in a virtual 3-D space and perspectively project said 3-D object onto the projection plane of view-point coordinate system,

said texture information storage means for storing texture information of each polygon forming respective shape models of different precision based on said shape models having different degrees of precision of said 3-D object, and

said image forming means for reading texture information of a shape model of precision corresponding to the polygons of said perspectively projected 3-D object from said texture information storage means by mapping said texture information onto the polygons for synthesizing an image to be displayed.

It is preferred that said texture information storage means stores highly resolute texture information for polygons in an image part requiring high resolution and a shape model of high precision.

It is also preferred that said texture information storage means stores highly resolute texture information for polygons in an image part requiring high resolution.

It is further preferred that said object data storage unit forms and stores an image part requiring high resolution for a shape model of high precision as independent polygons, and wherein said texture information storage means stores highly resolute texture information for polygons in an image part requiring high resolution.

It is further preferred that said object data storage unit stores a predetermined 3-D object as object data represented by shape models for close-up, middle-range and long-shot modes, and wherein said texture information storage means stores highly resolute texture information for polygons in an image part requiring high resolution of said close-up shape model.

It is further preferred that said object data includes vertex texture coordinates set for each vertex in the respective polygons of said shape mode 1, and wherein said image forming means calculates texture coordinates used as texture information read-out addresses for all dots in the polygons from input polygon vertex texture coordinates, the calculated texture coordinates being then used as addresses to read texture information from said texture information storage unit by mapping the read texture information onto the corresponding polygon for forming and displaying an image.

According to the present invention, part or all of the 3-D objects in the 3-D object data stored in the object data storage unit are previously stored as object data representing a plurality of shape models having different degrees of precision. As the view point in the view-point coordinate system and the 3-D object draw closer, the object data represented by a shape model of higher precision is read out.

If the 3-D object is far away from the view point, the 3-D object is displayed as a simple shape model formed by less polygons. Thus, the burden on the hardware can be reduced and it is possible to display more 3-D objects on the display.

Particularly, in a real-time computer graphic system in which the number of polygons to be displayed is limited, objects continuously changing their orientation and distance can be displayed with minimum number of polygons with the technique of the present invention. As a result, the image can be displayed in real time even if a scene requires many more polygons.

In addition, it is preferred that the texture information applied to the polygons each forming a shape model of a 3-D object is stored as image data of different resolution for each shape model and further for each of the polygons forming the shape model, rather than all the texture information having the same resolution.

In other words, the image synthesizing system of the present invention stores the texture information for each of the polygons forming each of the 3-D object shape models which have different degrees of precision.

Among polygons forming a shape model, a polygon representing an image part requiring high resolution is formed to provide texture information of corresponding high resolution. Thus, with a shape model of high precision, the texture information corresponding to all polygons forming such a shape model is stored as information of low resolution when an enlarged display object does not require very high resolution and as information of high resolution when an enlarged display object requires high resolution, rather than all the stored texture information having the same resolution. Therefore, the entire texture data can be compressed such that an image of high resolution can be displayed with little increase in the memory capacity for storing the texture information.

When the present invention is applied to display a 3-D object constantly varying in orientation and distance in the 3-D image space, the memory capacity used in the entire system can be saved more effectively.

By applying the present invention to a game playing apparatus, it is possible to provide an inexpensive game apparatus which can display many 3-D objects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an image synthesizing system constructed in accordance with the embodiment of the present invention.

FIG. 2 is a schematic view illustrating the principle of the image synthesizing system using a texture mapping technique.

FIG. 3 is a view illustrating the principle of a texture mapping in the image synthesizing system of the embodiment.

FIGS. 4A, 4B and 4C illustrate various shape models of a 3-D object used in the image synthesizing system of the embodiment.

FIGS. 5A, 5B and 5C illustrate game scenes formed by using the shape models of FIGS. 4A, 4B and 4C.

FIGS. 6A and 6B illustrate a close-up game scene formed by the shape models and the enlarged game scene thereof.

FIG. 7 is a view illustrating a texture information storage unit used in the image synthesizing system of the embodiment.

FIGS. 8A, 8B and 8C illustrate the details of texture information stored in the image synthesizing system of the embodiment.

FIGS. 9A and 9B illustrate the relationship between texture information used in a close-up model and positions of the model on which the texture information is applied.

FIG. 10 illustrates the relationship between middle-range texture information and a shape model on which the texture information is applied.

FIG. 11 illustrates the relationship between long-shot texture information and a shape mode 1 on which the texture information is applied.

FIG. 12 illustrates the principle of a conventional image synthesizing system.

BEST MODES FOR CARRYING OUT THE INVENTION

The present invention will now be described in detail with reference to the drawings.

FIG. 2 shows one preferred embodiment of a real-time display type image synthesizing system constructed in accordance with the present invention, in which parts similar to those of the aforementioned prior art are designated by identical reference numerals.

The image synthesizing system perspectively projects a 3-D object 310 which is represented as a shape model comprising a combination of a plurality of polygons in a virtual 3-D space 300, onto a given perspective projection plane 316 in a view-point coordinate system. Thus, a pseudo 3-D image 318 is displayed on a display.

In such an image synthesis, the image synthesizing system uses a technique known as texture mapping. As shown in FIG. 3, the image information of the 3-D object 310 is separated into image information for respective polygons 320-1, 320-2, 320-3 and so on and graphic information to be applied to the respective polygons (which is called "texture information" hereinafter) and is stored. When an image is to be output, texture information 340 and 342 are applied to the respective corresponding polygons 320-1, 320-2, 320-3 and so on so as to synthesize the image. Such an application of the texture information 340 and 342 is accomplished after the 3-D object 310 is perspectively projected onto the projection plane.

As described, the number of polygons which can be displayed in one second is limited to a certain degree when an image is to be displayed in real time through a 3-D computer graphic system. The present invention is characterized by that the real-time display type computer graphic system having limited number of polygons to be displayed in which a 3-D object continuously varying in orientation and distance can be displayed with less polygons and high resolution.

FIG. 1 is a block diagram of an image synthesizing system to which the present invention is applied.

The image synthesizing system comprises a player's control unit 10, a 3-D game space processing unit 20, a sorting unit 28 and an image synthesizing unit 30. The synthesized image is displayed on a display 40.

The player's control unit 10 is located on a control panel 314 so that a player 312 may input various control signals. In a driving game, for example, the player's control unit 10 may include a steering wheel, brake pedal, accelerator pedal and others, all of which are disposed on and near the control panel 31.

The 3-D game space processing unit 20 is responsive to the input signals from the player's control unit 10 and to a previously stored game program for processing a game playing various 3-D objects 310 in a virtual 3-D space 300.

Each of the 3-D objects 310 is represented as a shape model comprising a combination of a plurality of polygons. The 3-D object 310 is perspectively projected onto a perspective projection plane 316 in a moving view-point coordinate system, the information of the perspectively projected 3-D object being then output toward the sorting unit 28.

To accomplish such a processing, the game processing unit 20 comprises a 3-D calculation unit 22, an object data reading unit 24 and an object data storage unit 26.

The object data storage unit 26 stores image information of various 3-D objects represented as shape models each comprising a combination of a plurality of polygons. In this embodiment, particularly, 3-D object data representing racing cars played in various scenes are stored as plural object data represented by a plurality of shape models having different degrees of precision.

FIGS. 4A, 4B and 4C show shape models of object data of a racing car which is to be stored in the object data storage unit 26. As shown in FIGS. 4A, 4B and 4C, the object data storage unit 26 stores the object data for close-up, middle-range and long-shot modes, respectively.

The close-up object data shown in FIG. 4A represents the details