Computer graphics processing and selective visual display system – Computer graphics processing – Adjusting level of detail
Reexamination Certificate
1998-03-19
2001-08-14
Brier, Jeffery (Department: 2679)
Computer graphics processing and selective visual display system
Computer graphics processing
Adjusting level of detail
C345S182000, C345S182000
Reexamination Certificate
active
06275234
ABSTRACT:
BACKGROUND OF THE INVENTION
This application is based on Japanese Patent Application No. 9-75186, filed Mar. 27, 1997, the contents of which is incorporated herein by reference.
The present invention relates to a display control system used in personal computers and the like and a method for controlling display of three-dimensional graphics data.
Conventionally, a three-dimensional graphics function has been carried out on a workstation mainly for use in engineering such as CAD and CAM. Recently, even in personal computers, the three-dimensional graphics function has been supported for daily use representing entertainment software such as games.
In order to implement a three-dimensional graphics function, generally, not all 3D (three-dimensional) processing (geometry conversion, rendering, etc.) for drawing three-dimensional graphics, is executed by a CPU, but hardware called a 3D graphics accelerator is employed in order to cover part of the 3D operations. If the 3D graphics accelerator is used, a load can be distributed by causing the CPU to execute geometry conversion using floating-point arithmetic and by causing the accelerator to execute rendering including texture mapping and Z buffering, with the result that the 3D graphics can be drawn at high speed.
In recent personal computers, a display screen is improved in resolution and a graphics subsystem, which supports high-resolution display of 800×600 dots or 1024×768 dots, is the mainstream, whereas the size of a typical screen of 3D graphics is 640×480 dots. Thus, a problem poses that if 3D graphics are displayed on the high-resolution display screen, their display size is reduced in appearance.
If 3D graphics are drawn by setting their original screen to a large size of 800×600 dots or 1024×768 dots in advance, they can be displayed in full on the high-resolution display screen. If, however, the size of the original screen of the 3D graphics is set large in advance, all the 3D operations, such as geometry conversion and rendering necessary for drawing the 3D graphics, is increased in amount. This causes the load of the CPU and the power consumption of the 3D graphics accelerator to increase.
Personal computers are under restrictions on the performance of the CPU and the power consumption of the graphics subsystem and thus excessive processing cannot be executed by the CPU or the 3D graphics accelerator. For this reason, in personal computers, it is practically difficult to set the original screen size of the 3D graphics large before the drawing thereof.
As described above, the personal computers are under restrictions on the performance of the CPU and the power consumption of the graphics subsystem and thus the size of the original screen cannot be set large in advance in accordance with that of a screen on which 3D graphics are to be displayed. It is therefore difficult to display 3D graphics on a screen whose resolution is higher than that of the original screen.
BRIEF SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a display control system suitable for personal computers, wherein 3D graphics of high quality can be displayed by a screen size whose resolution is higher than that of the original screen size without setting the original screen size large before they are drawn, and a display control method for controlling display of the 3D graphics data.
In order to attain the above object, there is provided a display control system comprising: a memory for storing three-dimensional graphics data; three-dimensional acceleration means for executing three-dimensional operations including rendering processing for subjecting the three-dimensional graphics data stored in the memory to rendering, the three-dimensional acceleration means having scaling means for interpolating the three-dimensional graphics data subjected to the rendering by the rendering processing and enlarging a screen size of the three-dimensional graphics data subjected to the rendering; and a display monitor for displaying the three-dimensional graphics data obtained by the three-dimensional acceleration means.
In the display control system having the above constitution, three-dimensional graphics data having an original screen size of, e.g., 640×480 dots is written to a memory such as a video memory, and three-dimensional operations is executed with the original screen size unchanged. Of the three-dimensional operations including rendering and geometry conversion, a three-dimensional acceleration means serving as a three-dimensional graphics accelerator, executes the rendering such as shading, texture mapping and Z buffering to subject the three-dimensional graphics data to rendering. The screen size of the three-dimensional graphics data subjected to the rendering is the same as the original screen size. In the display control system of the present invention, the three-dimensional graphics data is input to the scaling means and undergoes scaling in order to increase in screen size and display it in full, though usually three-dimensional graphics data subjected to rendering is displayed on a screen as it is. If the scaling is executed for the three-dimensional graphics data after rendering, the screen size can be enlarged without increasing in amount of three-dimensional operations. Since the scaling is executed by interpolation, data of high quality can be displayed without distortion, unlike in a mere change in display magnification using a repetitive scan technique of repeatedly displaying the same raster data. According to the display control system of the present invention, therefore, three-graphics data of high quality can be displayed by a screen size the resolution of which is higher than the original screen size without setting the original screen size large before the three-dimensional graphics are drawn.
It is preferable that the display control system be provided with a color space conversion means for converting data of a YUV format to that of an RGB format. Thus, the color space of three-graphics data subjected to rendering or scaling can be changed from the YUV format to the RGB format which is usually used to display it on a display monitor.
It is also preferable that an on-screen area of the video memory be used to draw normal graphics data such as VGA and SVGA graphics data, an off-screen area thereof be used to execute the above three-dimensional operations for drawing three dimensional graphics data, and the video memory be used to draw both normal graphics data and three-dimensional graphics data. If, therefore, the memory space of the video memory is divided, the normal graphics data and three-dimensional graphics data can easily be synthesized and displayed. Since, furthermore, the off-screen area can be employed as a work area for executing three-dimensional operations by the three-dimensional acceleration means, the processing such as texture mapping requiring a relatively large memory size can be executed using a video memory without preparing a dedicated work memory.
In order to enhance display quality of the enlarged three-dimensional graphics, it is preferable to execute scaling by interpolation in both horizontal and vertical directions using horizontal and vertical scalers as the scaling means. If, however, vertical scaling involving interpolation is performed, an amount of processing for the scaling is increased. It is thus preferable that a first vertical scaling means for executing vertical scaling involving interpolation and a second vertical scaling means of a repetitive scan type for continuously outputting data on the same line be prepared as the vertical scaler and selectively used based on the relationship between the contents of scaling determined by a magnification and the like and the performance of the display system.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advan
Brier Jeffery
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Good-Johnson Motilewa
Kabushiki Kaisha Toshiba
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