JPH0285979A - 3D graphic processing device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a three-dimensional graphic processing device, and more specifically, it performs predetermined coordinate transformation processing on world coordinate system data and predetermined clip processing. The present invention relates to a three-dimensional graphic processing apparatus that obtains device coordinate system data by performing the following steps.

<Prior art and problems to be solved by the invention> Three-dimensional graphic processing devices with various configurations have been provided in the past, but these three-dimensional graphic processing devices do not comply with the three-dimensional graphics standard. Compliant 3D figure processing flow (hereinafter referred to as viewing vibe line)
has been adopted.

As for the above viewing vibe line, ■ Standard specification PHIGS (Progravwer'5H1e
rarchfcal Interactive Gra
phlcs System), and ■ Standard GKS-3D (Graphica
KernelSysLegen-3D) is generally used.

To explain in more detail, the viewing vibe line that complies with the above standard PHIGS, as shown in Figure 5, is created by applying modeling transformation processing to struc- ture element data defined in the modeling coordinate system. Data in the world coordinate system (hereinafter abbreviated as world coordinate system data) is generated by combining each struc- ture element data.

Then, data in the view reference coordinate system (hereinafter referred to as view reference coordinate system data) is obtained by applying field of view conversion processing to the world coordinate system data, and the view reference coordinate system data is converted to the projection viewport. Data in a normalized projected coordinate system (hereinafter abbreviated as normalized projected coordinate system data) is obtained by performing projection processing and clipping processing based on the projection viewport. After that, data in the device coordinate system (hereinafter referred to as device coordinate system data) is obtained by performing clip processing based on the workstation window and workstation conversion processing on the normalized projected coordinate system data, and Visual display is performed using a display device or the like.

The processing up to obtaining the above world coordinate system data is performed in a processing section independent of the workstation.
The processing after the field of view conversion processing is performed in a processing section that depends on the workstation.

As shown in Figure 6, the viewing vibe line that complies with the standard GKS-3D is created by performing normalization transformation processing on primitive data defined in the world coordinate system (data in the normalized coordinate system). (hereinafter abbreviated as normalized coordinate system data) is obtained, subjected to segment conversion processing as necessary, and then subjected to normalized clip processing to extract only necessary portions of the normalized coordinate system data.

Then, view reference coordinate system data is obtained by performing field of view transformation processing on the extracted normalized coordinate system data,
Clipping processing based on the view volume and projection processing on the projection viewport are performed on the view reference coordinate system data to obtain normalized projected coordinate system data. Thereafter, the normalized projected coordinate system data is subjected to clip processing based on the workstation window and workstation conversion processing to obtain device coordinate system data, which is visually displayed on a CRT display device or the like.

Note that the processing up to obtaining the normalized coordinate system data is performed in a processing section independent of the workstation, and the processing after the visual field conversion processing is performed in a processing section dependent on the workstation.

As is clear from the above explanation, even in the Viewing Vibration line that complies with the standards for the above direction, world coordinate system data or normalized coordinate data is generated in a processing section independent from the workstation, and the workstation The device coordinate system data is converted by sequentially performing field of view conversion processing, clip processing based on view volume or view boat, projection processing, clip processing based on the workstation window, and workstation conversion processing after clipping in the station-dependent processing part. is being generated.

Therefore, when generating device coordinate system data based on world coordinate system data, it is necessary to perform clip processing based on the view volume or viewport, and clip processing based on the workstation window, which increases the number of clip processing operations. Therefore, there is a problem in that the overhead of the viewing vibe line as a whole becomes large, and as a result, the graphic display speed decreases.

<Object of the invention> This invention was made in view of the above problems,
It is an object of the present invention to provide a three-dimensional graphic processing device that can greatly simplify clip processing in a workstation-dependent section and improve graphic display speed by a factor of 11.

Means for Solving the Problems> In order to achieve the above object, the three-dimensional graphic processing device of the present invention includes projection means for projecting a view volume onto a projection viewport, and a combination of the projection viewport and a workstation window. The image forming apparatus includes a region extracting means for extracting a common region, and a clipping means for performing clip processing based on the common region.

However, the above area extraction means extracts a common area based on a projection viewport and a workstation window set on a normalized projected coordinate system,
Preferably, the extracted common area is normalized.

Further, it is preferable that the clipping means performs homogeneous coordinate clipping processing based on a normalized common area.

Further, it is preferable that the three-dimensional graphic processing device conforms to the three-dimensional graphics standard PHIGS or GKS-3D.

Effects> The three-dimensional graphic processing device with the above configuration performs predetermined coordinate transformation processing on world coordinate system data, and also performs predetermined clip processing to obtain device coordinate system data. When obtaining three-dimensional graphic data, a common area between the projection viewport and the workstation window is extracted by the area extracting means, a view volume is projected onto the projection viewport by the projection means, and then a clipping means is used to extract the common area between the projection viewport and the workstation window. By performing clip processing based on the extracted common area, three-dimensional graphic data corresponding to the area to be actually displayed can be obtained.

When the area extraction means extracts a common area based on a projection viewport and a workstation window set on a normalized projected coordinate system, and normalizes the extracted common area, By performing clip processing based on the extracted and normalized common area, three-dimensional graphic data corresponding to the area to be actually displayed can be obtained.

In addition, if the above-mentioned clipping means performs homogeneous coordinate clipping based on a normalized common area, it is possible to perform view volume clipping and workstation window clipping by simply performing homogeneous coordinate clipping. It is possible to obtain the same results as when the processes are performed sequentially.

Furthermore, the same effect as described above can be achieved even when the three-dimensional graphic processing device conforms to the three-dimensional graphics standard PHIGS or GKS-3D.

<Example> Hereinafter, embodiments will be described in detail with reference to the accompanying drawings showing examples.

FIG. 2 is a block diagram of main parts showing one embodiment of the three-dimensional figure processing device of the present invention, in which region setting data set by external operation is input and the projection viewport (third A view boat setting section (1) that sets the viewport (see Figure A), and a window data holding section that holds the workstation window area (see Figure 3 B) that is preset in correspondence with the normalized projected coordinate system. 0, a common area extraction unit G that extracts a common area between the projection viewport and the workstation window area on the normalized projection coordinate system (see Figure 3C), and a common area extraction unit G) that extracts the common area between the projection viewport and the workstation window area on the normalized projection coordinate system, Ga-
A normalization projection unit (4) that projects onto an area normalized to be between 1 and 1 (see Figure 4), and a common projection unit (4) that projects the extracted and normalized area onto the normalized area (see Figure 4). Clip processing unit (5) that performs homogeneous coordinate clip processing based on the area
and a workstation conversion unit (6) that performs workstation conversion processing on the clipped data.
).

FIG. 1 is a schematic diagram showing the viewing vibe line of the present invention, showing only workstation-dependent parts.

That is, view reference coordinate system data is generated by performing field-of-view transformation processing on world coordinate system data, and after projection transformation processing is performed from the view volume to the projection viewport, the connection between the projection viewport and the workstation window is Device coordinate system data is obtained by performing clip processing based on the common area and further performing workstation conversion processing.

Therefore, it is necessary to apply the necessary transformation processing to a large number of world coordinate system data, but in terms of clip processing, it is necessary to perform the necessary transformation processing on each of the world coordinate system data. As the number of clipping operations is reduced, the time required for graphic data processing can be shortened, and the overall graphic display speed can be increased.

To explain in more detail, in a graphic display device, there is a world coordinate system that defines the target figure and a device coordinate system that performs visual display.The display limit of the device coordinate system is defined. Rectangular workstation window (see Figure 3C)
In addition, a rectangular parallelepiped projection viewport (see FIG. 3C) defines the display area of the target figure. Therefore, the object graphic is visibly displayed only in the common area of the projection viewport and workstation window (see FIG. 3C).

Therefore, if homogeneous coordinate clipping is performed based on the common area between the projection viewport and workstation window defined on the normalized projected coordinate system, view volume clipping and workstation window clipping can be performed sequentially. You can get the same results as in the case. Thereafter, by further performing workstation conversion processing, it is possible to finally obtain displayable device coordinate system data.

As is clear from the above explanation, if you extract the common area between the projection viewport and the workstation window once, then you can perform clip processing using the extraction results, view volume clip processing, Since it is possible to obtain the same data as when the workstation window clip processing is performed sequentially, the processing can be simplified as a whole, and the graphic display speed can be improved.

<Effects of the Invention> As described above, the invention of ML extracts the common area between the projection viewport and the workstation window in advance, and then extracts the common area between the projection viewport and the workstation window in advance, and then extracts the common area from the extracted common area while projecting the view volume onto the projection viewport. Since clip processing is performed based on
As a result, a unique effect is achieved in that the graphic display speed can be improved.

The second invention normalizes the common area extracted based on the projection viewport and the workstation window, so it is only necessary to perform clip processing using the normalized common area, simplifying the clip processing as a whole. This has the unique effect of improving graphic display speed.

The third invention simply performs homogeneous coordinate clipping,
This has the unique effect of being able to obtain the same results as when view volume clip processing and workstation window clip processing are performed sequentially.

The fourth invention has the unique effect of being able to greatly simplify the clip processing in the workstation-dependent section without impairing the state of compliance with the three-dimensional graphics standard.

[Brief Description of the Drawings] Fig. 1 is a schematic diagram showing a viewing pipeline according to the present invention, Fig. 2 is a block diagram of main parts showing an embodiment of a three-dimensional graphic processing device according to the present invention, Fig. 3, 4 is a schematic diagram explaining clip processing, 5 is a schematic diagram illustrating a conventional example of a viewing pipeline that complies with standard PHIGS, and 6 is a schematic diagram illustrating standard PHIGS.
1 is a schematic diagram showing a conventional example of a viewing pipeline compliant with KS-3D. (5)...Clip processing section,

Claims (1)

[Claims] 1. In a three-dimensional graphics processing device that performs predetermined coordinate transformation processing on world coordinate system data and also performs predetermined clipping processing to obtain device coordinate system data, the view volume is converted into a projection viewport. a projection means for projecting onto the projection viewport, an area extraction means (3) (4) for extracting a common area between the projection viewport and the workstation window, and an area extraction means (3) (4) for extracting a common area between the projection viewport and the workstation window.
3, characterized in that it has a clipping means (5) that performs clipping processing based on the common area extracted by
Dimensional figure processing device. 2. The area extraction means (3) and (4) extract a common area based on the projection viewport and workstation window set on the normalized projected coordinate system, and normalize the extracted common area. A three-dimensional graphic processing apparatus according to claim 1. 3. The three-dimensional graphic processing apparatus according to claim 1, wherein the clipping means (5) performs homogeneous coordinate clipping processing based on a normalized common area. 4. 3D graphics standard PHIGS or G
A three-dimensional graphic processing device according to claim 1, which complies with KS-3D.