JPH02126379A - Graphic display device - Google Patents

Abstract

PURPOSE:To shorten the write time of coordinate data by directly writing the coordinate data to a memory storage position when it is decided that the data are not written before the memory storage position. CONSTITUTION:Coordinate data Xc and Yc are respectively added as the address of a depth buffer memory 8 and the address of a flag memory 13, and coordinate data Zc are set as the data input of a comparator 36 and a memory 8. As soon as information is read from the memory 13, whether or not the writing is executed before is determined, and data Z are sent from the memory 8 to the comparator 36. When the data are not written before, the data Zc are unconditionally written to the memory 8, and the processing is advanced in response to the next coordinate output from a straight line generator 7. When the data Z are written to the memory 8 before, based on the comparison result between the data Z and Zc (Zc < Z), the write processing of the data Zc to the memory 8 are executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a graphics display device for displaying graphics, etc., for writing data necessary for displaying graphics into a memory.

[Conventional technology]

FIG. 3 is a block diagram of the configuration of a raster scan type graphic display device that uses a conventional data writing method that performs hidden surface processing using a depth buffer memory. In the figure, 1 is a computer (not shown) and interface signal,
2 is an interface circuit, 3 is a control device that converts display data and display commands sent from the computer through this interface circuit 2 into an internal format, and 4 is a storage circuit that stores display data and display commands that have been converted to the internal format. be. The data written in the memory circuit 4 is given to the linear generator 7 via the coordinate conversion circuit 5 and the clip circuit 6 based on instructions from the control device 13. 8 is the coordinate data Xc, Ye, from the straight line generator 7.
A first controller that receives Ze as input and reads data Z from the storage device addressed by the coordinate data Xc and Yc, and if Zc<Z, writes the coordinate data Zc to the storage location and outputs an update flag signal. A depth buffer memory as a memory, and a frame 9 as a second memory in which display information such as brightness or color set in advance is written in a storage position addressed by the coordinate data Xe and Ye when the update flag signal is input. It is buffer memory.

10 is a CRT interface circuit that sends display data to the CRT II, and 12 is an input device that sends data to the control device 3.

FIG. 4 is a configuration block diagram of the graphic display device including details of the depth buffer memory 8, and 1 to 12 are the same as in FIG. 3.
or a corresponding part. 31°32.33 is the coordinate data generated by the linear generator 7, and the coordinate data 31 is Xc,
Coordinate data 32 is Yc, coordinate data 33 is Zc, and 34 is a strobe signal that samples coordinate data 31, 32, and 33. 35 is data Z read out from the depth buffer memory 8, and 36 is a Z coordinate value comparator, which compares coordinate data 33.35 and outputs an output 37. Output 37
is a flag signal indicating Zc≦Z, which serves as a write signal to the depth buffer memory 8 and a write flag to the frame buffer memory 9.

Next, the operation will be explained. The straight line generator 7 generates starting point data Xs, Ys, Zs and ending point data Xi, YE,
Depth buffer 1 that realizes hidden surface processing algorithm by sequentially generating coordinate data from the start point to the end point based on ZE
Give it to memory 8. The depth buffer memory 8 reads data Z (35) from the depth buffer memory location addressed by the coordinate data Xc (31) and Yc (32) among the coordinate data XC, Ye, and Zc generated by the linear generator 7, If Zc≦Z, coordinate data Z
Write c(33) to that memory location and save the coordinate data X
An update flag 37 indicating that c, Yc and the depth buffer memory 8 have been updated is given to the frame buffer memory 9. Note that if the depth buffer memory 8 is not updated, the coordinate data and update flag are not provided to the frame buffer memory 9. The frame buffer memory 9 is
When the update flag is received, display information such as brightness range, color, etc. set in advance is written into the storage location of the frame buffer memory 9 addressed by the coordinate data Xc, Yc. The data written in the frame buffer memory 9 is read out according to the display address generated by the CRT interface circuit 10, and is sequentially sent to the CRTII for display. Further, data is given to the control device 3 by the input device 12 as necessary.

FIG. 5 shows an example of a conventional writing sequence to a depth buffer. A is coordinate data Xc from the linear generator 7,
Yc, 7: output timing of c, B is coordinate data Xc,
Output timing of coordinate data Z within the address of the depth buffer memory 8 specified by Yc to the comparator 36;
C is the comparison timing between the coordinate data Z and Zc in the comparator 36, and D is the comparison timing of the depth buffer memory 8 according to the comparison result.
The timing of writing data to is shown below.

In step 1, coordinate data Xc, Yc are given as addresses of the depth buffer memory 8, and coordinate data Zc is set in the comparator 36.

In step 2, data Z within the specified address of the depth buffer memory 8 is output and set in the comparator 36. In step 3, coordinate data Z and Zc are compared and the results are output. In step 4, the contents of the depth buffer memory 8 are updated according to the comparison result.

[Problem to be solved by the invention]

The data writing method in conventional graphic display devices operates as described above, so if coordinate data Zc that has not been previously written to the depth buffer memory is sent, it is unconditionally written to the depth buffer memory. Even though the coordinate data Zc can be written, the writing time to the depth buffer memory is shortened because the coordinate data Zc is written to the depth buffer memory after comparing the coordinate data Zc from the linear generator with the coordinate data Zc from the linear generator. There was a problem that the length of the

The inventions of , - were made to solve the above-mentioned problems, and the first memory (depth buffer memory)
To obtain a graphic display device that can unconditionally write and perform h when coordinate data that has not been previously written to is sent, and that can perform writing at high speed. The purpose is to

[Means to solve the problem]

The graphic display device according to the present invention detects whether data Z has been previously written to the storage location of the first memory (depth buffer memory 8) addressed by the coordinate data Xc, Yc generated by the linear generator 7.・Third memory that stores flag information indicating whether
3), the first memory (depth buffer memory 8
), if it is determined based on the flag information that the data Z has not been previously written to storage location 1, the coordinate data Zc is written without comparing the data Z with the coordinate data Ze from the linear generator 7. 1 (depth buffer memory 8).

[Effect]

In this data writing method, if it is determined from the flag information that data Z has not been previously written to the storage location of the first memory (depth buffer memory 8), data Z and coordinate data Zc are compared. First, the coordinate data Zc is stored in the first memory (depth buffer memory 8
) is written directly to the storage location. Therefore, the time required to write the coordinate data Zc becomes shorter.

[Embodiments of the invention]

FIG. 1 is a block diagram of a graphic display device according to an embodiment of the present invention. In FIG. 1, components corresponding to those shown in FIG. 4 are designated by the same reference numerals, and their explanations will be omitted. In FIG. 1, reference numeral 13 indicates coordinate data Xc generated by the linear generator 7.

A flag memory 38 serves as a third memory for storing flag information indicating whether data Z has been previously written to the storage location of the depth buffer memory 8 addressed by Yc; 38 is a flag K of the flag memory 13; This is a signal that controls the writing method to the depth buffer memory 8.

Next, the operation of this embodiment will be explained with reference to the timing chart shown in FIG. In FIG. 2, A is the output timing of the linear generator 7, B is the input timing from the depth buffer memory 8 to the comparator 36, and C is the data Z from the depth buffer memory 8 and the coordinate data from the linear generator 7. E is the timing of comparison with Zc, E is the timing of determining whether data Z has been previously written to the address 8 of the depth buffer memory 8 based on the flag information from the flag memory 13, and DI is the timing when data Z has not been previously written. Writing timing of coordinate data Zc to depth buffer memory 8, D2 is data Z and coordinate data Zc
The timing of writing the coordinate data Zc into the depth buffer memory 8 based on the comparison results with the above is shown.

In step 1, coordinate data Xc, Yc are given as the address of the depth buffer memory 8 and the address of the flag memory 13, and the coordinate data Zc is set as the data input of the comparator 36 and the depth buffer memory 8. In step 2, information is read from the flag memory 13 to determine whether writing has been performed before, and at the same time data Z is transferred from the depth buffer memory 8 to the comparator 36.
Send out. In step 3, if writing has not been performed before, the coordinate data Zc is unconditionally written to the depth buffer memory 8 at the timing of Dl, and processing moves on to the next coordinate output from the straight line generator 7. .

If data Z has been previously written to depth buffer memory 8, coordinate data Zc is written in step 4 based on the comparison result of data Z and coordinate data 7, c (Z C < Z), as in the past. Write processing to the depth buffer memory 8 is performed.

[Effects of the Invention] As described above, according to the present invention, when it is determined based on the flag information that data Z has not been previously written to the storage location of the first memory, the comparison between data Z and coordinate data Zc is Since the coordinate data Zc is directly written to the storage location of the first memory without performing the above, there is no need to compare and judge whether to write to the first memory if the display information does not overlap with the same coordinates. The writing timing of the coordinate data Zc to the first memory can be performed at high speed,
The effect is that graphic display processing can be executed efficiently.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the configuration of a graphic display device according to an embodiment of the present invention, FIG. 2 is a timing chart for explaining the operation of this embodiment, and FIG. 3 is a diagram of a graphic display using a conventional data writing method. FIG. 4 is a block diagram showing the overall structure of the display device, FIG. 4 is a block diagram showing details of the graphic display device shown in FIG. 3, and FIG. 5 is a timing chart for explaining the operation of this conventional example. 7... Linear generator, 8... Depth buffer memory
(first memory), 9... frame buffer memory (
13...Flag memory (third memory). Agent: Masuo Oiwa (and 2 others) Procedural amendment (voluntary) 1. Waiting for display of case 1 item 3-280628 2. Invention title graphic display device 3. Person making the amendment 4. Attorney's amendment Target drawing column. Content drawing of the amendment. Figure 2 is supplementary IF as shown in the attached sheet. that's all

Claims (1)

[Claims] a straight line generator that generates straight line coordinate data Xc, Yc, and Zc regarding a figure; and a linear generator that receives the coordinate data Xc, Yc, and Zc as input and reads out data Z from a storage position addressed by the coordinate data Xc and Yc; Zc
<Z, the coordinate data Zc is written in the storage location and the first memory outputs the update flag signal, and when the update flag signal is input, the storage location is set in advance to be addressed by the coordinate data Xc, Yc. In a raster scan type graphic display device, the display device includes a second memory in which display information such as brightness or color is written. A third memory is provided for storing flag information indicating whether writing of Z has been performed, and when it is determined based on the flag information that data Z has not been previously written to the storage location of the first memory, A graphic display device characterized in that the coordinate data Zc is directly written into the storage location of the first memory without comparing the data Z and the coordinate data Zc.