JPH05260476A - Videotex system - Google Patents

Abstract

PURPOSE:To allow a terminal equipment side to use a CG means to display freely a display object by forming the transmission pattern data with data such as a shape, shading and a light source in order to display the display object with the computer graphics(CG). CONSTITUTION:Pattern data to be sent consist of polygon data representing a shape of a display object, shading data representing the shading method, light source data representing a position of a light source, a direction, a strength, a color and a shape and mapping data representing a display color and its pattern, and visual point data representing a position of a visual point and a position of a noted point. The CG data as above are stored in a Videotex center equipment 26 and sent by a data request signal from a Videotex terminal equipment 20. The received CG data are expanded by the Videotex terminal equipment 20 and displayed on a screen 21 of the display device. The visual point of the screen 21, the visual angle and the light source or the like are freely changed by using the controller 22 by the user.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen data transmission system for a videotex system.

[0002]

2. Description of the Related Art On the terminal side of a conventional videotex system, a two-dimensional screen based on screen data such as received graphics and natural images is directly displayed on a display device.

[0003]

The above-mentioned two-dimensional screen is
The composition is decided by the center side, and it is not possible to freely change the composition of the screen on the terminal side.

For example, on the screen displaying the car, the position where the car is viewed is determined, and it is not possible to view the car from a free viewpoint such as front, rear, left and right.

[0005]

According to the present invention, screen data to be transmitted is (1) polygon data (shape model) representing a shape of a display object (2) shading data representing a shading method (3) light source position , Light source data (light source model) representing the direction, strength, color, shape, etc. (4) Mapping data representing the color and pattern of the surface (surface model) (5) View point data, viewpoint data representing the position of the gazing point ( The visual field model) and the like can be freely displayed on the terminal device side by computer graphics (CG) means.

[0006]

An embodiment of the present invention will now be described with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.

1 is a mode switching code (DI code)
Is a code for switching the conventional code mode, message mode, transparent mode, melody mode, etc., and is represented by 1-byte data. In the present invention, a new value is assigned to this switching code and the CG mode is set. When the terminal device receives this switching code, the terminal device switches to the CG mode,
Until the new switch code is received, the received data is processed as CG mode data.

Reference numeral 2 is data representing the data length, and represents the total data length after this data in the CG mode.

Reference numeral 3 denotes a data identifier (OP code), which indicates what data is after the identifier. As the type of identifier, OP (p) indicating polygon data,
There are OP (c) indicating shading number, OP (b) indicating shading information, OP (l) indicating light source information, OP (m) indicating mapping data, OP (s) indicating initial viewpoint information, and the like.

Reference numeral 4 is data representing the data length after the identifier, and indicates how many bytes the data belonging to the identifier is.

Reference numeral 5 is polygon data belonging to the identifier OP (p).

One polygon is represented by coordinates of three or more vertices, and one vertex coordinate has three coordinates of X coordinate, Y coordinate and Z coordinate.
Expressed in two coordinates. Therefore, the polygon data is
Vertex 1X coordinates, Vertex 1Y coordinates, Vertex 1Z coordinates, Vertex 2X
They are arranged in the order of coordinates, vertex 2Y coordinates, vertex 2Z coordinates. The number of polygons indicated by one identifier OP (p) is one, and the number of vertices of the polygon is determined by the number of coordinates in the polygon data.

6 is an end code, which is a code indicating the end of the data string in one identifier.

Reference numeral 7 is data indicating a shading number belonging to the identifier OP (c). There are various types of shading methods, such as phon shading, bling shading, and Lambertian shading. A number is assigned to each shading method, and this number specifies which shading method to use.

Reference numeral 8 is data of shading information belonging to the identifier OP (b). This data is composed of a 1-byte number and point coordinate data represented by one X coordinate, Y coordinate, and Z coordinate. A pattern on the surface of the object composed of polygons is assigned to the number, and the pattern to be applied is designated. The coordinate data specifies the reference point of the pattern. For example, when a ripple pattern is formed on the surface of an object, the number indicates the ripple pattern number and the coordinate data indicates the center of the ripple. When texture mapping is applied to the object surface, the number indicates texture mapping, and the coordinate data indicates a reference point to which the texture is attached.

Reference numeral 9 is light source information belonging to the identifier OP (l). This data is composed of a 1-byte number, color data for each of R, G, and B, and point coordinate data represented by X coordinates, Y coordinates, and Z coordinates. The type of light source is assigned to the number. There are various types of light sources, such as point light sources, surface light sources, and spot light sources. This number specifies which light source to use. The color data specifies the color and intensity of the light source for each of the R, G, and B color components. The coordinate data specifies the position of the light source and the direction of the light source.

Reference numeral 10 is mapping data belonging to the identifier OP (m). It is used as texture mapping data when texture mapping is specified in the data of the identifier OP (b). The data structure uses the video image natural image data format. For example, in the case of uncompressed data, it is composed of R, G, B color component data for the pixel size of the mapping pattern. If the data is compressed, it is possible to use the international standard ADCT method.

Numeral 11 is visual field data belonging to the identifier OP (s). This data is composed of two point coordinate data represented by X coordinate, Y coordinate and Z coordinate and a viewing angle. The coordinate data shows the viewpoint coordinates and the gazing point coordinates, and the view angle shows the view angle.

FIG. 2 is a block diagram of a videotex system using the CG data transmission of the present invention. 20 is a videotex terminal device, 21 is a display device for displaying the received CG data on a screen, and 22 is a terminal device. A controller for a person to change the viewpoint, viewing angle, light source, etc. of the screen, 23 and 25 are ISDN or telephone line subscriber lines, 24 is an ISDN or telephone line communication network, and 26 is a videotex center device. The videotex terminal device 20 and the videotex center device 26 are connected to the communication network 2
4 and the CG data is stored in the videotex center device 26 and transmitted by a data request signal from the videotex terminal device 20. The CG data follows the format shown in FIG. The received CG data is the videotex terminal device 20.
Is developed and displayed on the display device as a screen 21. The controller 22 allows the user to freely change the viewpoint, viewing angle, light source, etc. of the screen 21.

The operation of the videotex terminal device 20 when receiving CG data will be described with reference to the flowchart of FIG.

First, when the CG data transmitted from the videotex center device 26 is received (step 3
0), it is determined from the DI code whether the data is CG data (step 31). If the received data is not CG data, control is transferred to conventional videotex data processing. If the received data is CG data, it is determined what data the data following from the next OP code is (step 32), and the control is shifted to each processing. For example, if the OP code is OP (c), a shading number setting process is performed (step 33). In this process, data up to the end code is processed. When the shading number setting process is completed, the data length LI is determined (step 34). Here, the processing from step 32 to step 34 is repeated until the data processing for LI is completed. LI
When the minute data processing is completed, rendering calculation (step 35) is performed based on the data processing result, and the screen is displayed on the display device (step 36). At this point, the user of the videotex terminal device can obtain the screen viewed from one viewpoint, but when the user of the videotex terminal device operates the controller (step 37), according to the operation of the controller, The screen display is updated by changing the viewpoint information, the light source information, etc. in the received data and performing the processing from step 32 to step 36 again.

As described above, C in the videotex system
Although the G data transmission is exemplified, the present invention can be applied to other suitable image data transmission systems.

[0024]

As described above in detail, according to the present invention, the CG data is received from the center device, and the user of the terminal device can freely change the viewpoint and view the three-dimensional screen in an interactive manner. In addition to being possible, it is possible to shorten the data communication time because it is possible to freely change the viewpoint, viewing angle, light source, etc. with limited screen data.

[Brief description of drawings]

FIG. 1 is a diagram showing CG data transmission according to an embodiment of the present invention.

FIG. 2 is a block diagram of a videotex system using CG data transmission of the present invention.

FIG. 3 is a flowchart for explaining the operation of the videotex terminal device when receiving CG data.

[Explanation of symbols]

 20 Videotex terminal device 21 Screen displaying CG data on display device 22 Controller 23, 25 ISDN or telephone line subscriber line 24 ISDN or telephone line communication network 26 Videotex center device

Claims (1)

[Claims] 1. A videotex system comprising a center device for storing screen data, a communication network for transmitting the screen data, and a terminal device having a function of receiving the screen data and displaying it on a display device. , For displaying a display object by computer graphics (CG), (1) polygon data representing a shape (shape model) (2) shading data representing a shading method (3) position, orientation, strength of a light source, Light source data (light source model) that represents colors, shapes, etc. (4) Mapping data (surface model) that represents surface colors and patterns (5) Viewpoint data that represents the position of the viewpoint and the gazing point (visual field model) Or a videotex system characterized by containing data composed of a minimum required part of data.