JPH0644367A - Pattern data forming method - Google Patents

Abstract

PURPOSE:To improve the compression efficiency of a pattern decided by data defined by plural planes for designating the color numbers of respective does used for a computer device for forming a picture with the set of patterns. CONSTITUTION:The frequency of using the color numbers is found for the data defined by the plural planes for designating the color numbers of the respective dots of the pattern, and the small color numbers are assigned again in frequently-used order. Thus, when the numbers are assigned again, the dispersed color data are summerized and especially, zero data are gathered into the specified plane. As a result, the array of the same data can be expressed like (number) X (data value) and efficient data compression is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming pattern data in a computer system which uses a means for forming a screen with a set of patterns having a fixed size.

[0002]

2. Description of the Related Art A computer used in the present invention forms a screen by a set of patterns of a certain size, and a typical computer of this type is a computer game machine. A computer game machine that employs a method of overlapping two types of screens called a background and a sprite will be described as an example.

FIG. 1 is a diagram showing set values of respective registers constituting a display screen. The setting value in each horizontal direction is in units of the number of characters, and the vertical direction is in units of the number of rasters.

In the system of this example, the image display is managed separately for the background (background) and the sprite (foreground). For example, one unit of character is 8x8 dots, while that of sprite is 16x1 dots.
It is managed with 6 dots. This will be described below according to this example.

The background screen is composed of patterns called "characters" as a unit. Figure 2
Consider an example in which the background screen is composed of 32 × 32 characters as shown in FIG. The numbers in the boxes indicate the addresses in hexadecimal.

This background screen is managed in the VRAM of the memory in the computer as shown in FIG. Background attribute table (BA
T) is a table set in the VRAM to specify what kind of character and what color is displayed at each character position on the virtual screen.

A character code representing a character pattern and a CG color code (CG COLOR) representing a color are designated for each address. As shown in FIG. 4, in this example, the CG color code is designated by 4 bits and the character code is designated by 12 bits of data.

As the character code, a character number defined by a character generator (CG) in the VRAM is designated, and an actual character pattern is registered in the character generator (CG) corresponding to this number.

In the character generator (CG), the character pattern is defined as shown in FIG. Since a character composed of 8 × 8 dots on the screen needs to be defined with a color number of 4 bits for each dot, four 8 × 8 dot surfaces are used in the character generator (CG). Each surface is called CH0, CH1, CH2, CH3, and one pattern is defined by a total of 16 words of information.

As described above, the background screen is VRA.
It is managed by a background table (BAT) and a character generator (CG) in M, and is displayed on the screen according to the contents of this memory. FIG. 6 shows the connection and connection between individual records of the BAT and the character generator (CG).

How the character is actually displayed on the video screen will be described. The display control of the background screen is performed during the horizontal display period. The flow of data for displaying one character will be described.

As shown in FIG. 7, first, an address is generated from the raster position and BAT is read to obtain a character code and a CG color code.

Next, as shown in FIGS. 8 and 9, from the character code, a character generator (CG) is generated.
Address is generated, the pattern is read, and the result is loaded into the shift register in the video display controller (VDC).

In this case, the character generator (C
G) access is 2 words (CH0,
CH1 and CH2, CH3), and one word (CH0, CH1 or CH2, CH3) is read in four-color display.

As shown in FIG. 10, both the CG color code and the captured pattern data are output from the shift register. The video output at this time is as shown in FIG. VD7 to VD4 have CG color code,
Bits CH3 to CH0 appear in VD3 to VD0.
0 is output to VD8 (SPBG).

The data of VD0 to VD8 are matched with a color palette (color table RAM) and converted into color image data, and a video color encoder (VC) is used.
Sent to E).

A video color encoder (VCE) is a TV
When the RGB signals and image color signals for images are converted and transferred to the television screen, the final image is displayed on the television screen.

The color palette has a structure as shown in FIG. When handling the background screen, VD8 is set to 0, so the background block can be selected from the values of VD4 to VD7, and VD0 to VD
The dot color in the block can be extracted from the value of 3.

The base values of VD4 to VD7 are CG color codes, and those of VD0 to VD3 are CH0 to CH.
It is 3.

Since the system automatically performs the above processing, the user program only needs to prepare the VRAM and the color palette in advance.

As described above, the character color is C
4 of G color code and character generator (CG)
It is decided by the plane. The CG color code selects a color block of the color palette, and the character generator (CG) determines which color of the extracted color pattern.

Character generator (CG) is 8 × 8
Since it consists of four dots, one unit of character consists of 32 bits. In the game, a large number of such characters are prepared to form the background screen for the game.

Next, the sprite screen will be described.
The pattern and color of the character are determined by the background attribute table (BAT) and the character generator (CG), but that of the sprite is determined by the sprite attribute table (SAT) and the sprite generator (SG).

Although the contents of the records are different, the sprite attribute table (SAT) corresponds to BAT and the sprite generator (SG) corresponds to CG. Like the character generator (CG), the sprite generator (SG) has four faces.
The color number is determined from the surface and points to the pattern color on the color palette.

[0025]

Problem to be Solved by the Invention Character generator (CG) data and sprite generator (S)
G) Data compression is absolutely necessary in order to efficiently use the storage capacity of the auxiliary storage device. However, the CG data and SG data are scattered on four sides.

Therefore, when data is compressed and stored, there is a problem in that the data cannot be compressed in a cohesive manner and the compression itself becomes inefficient. It is an object of the present invention to collect color data that are scattered in a uniform manner with the same data (especially zero data) and perform efficient data compression.

[0027]

According to the present invention, the efficiency of data compression is improved by reassigning the color number of each dot of pattern data as follows.

The frequency of use of the color number is calculated. Renumber smaller color numbers in descending order of frequency of use.

When the numbers are reassigned in this way, the scattered color data are collected. In particular, zero data gathers on the 2nd plane (CH2) and the 3rd plane (CH3).

As a result, the same data sequence can be expressed as (number) × (data value), and efficient data compression is possible. Needless to say, it is necessary to prepare the color pattern so that the block of the color palette for the newly re-assigned color number pattern has the same color as before correction.

[0031]

EXAMPLE As an example of the present invention, character generator (CG) data as shown in FIG. 13 will be described.

FIG. 14 shows the plane data (CH0 to CH3) represented by the binary numbers in FIG. 13 as a set of color numbers in the hexadecimal numbers. Looking at the frequency of use of hexadecimal color numbers,

2 ---> 36 times 3 ---> 13 times A ---> 8 times 7 ---> 4 times 1 ---> 2 times 6 ---> 1 time

It becomes Sort them in order of frequency of use (already sorted in the above example) and assign smaller color numbers in order of frequency of use. That is, in the above example,

2 ---> 1 3 ---> 2 A ---> 3 7 ---> 4 1 ---> 5 6 ---> 6

It becomes If the contents of FIG. 14 are rewritten with this new color number, it becomes as shown in FIG. Further, if this is made into a bit configuration for each plane, it becomes as shown in FIG.

As can be seen by comparing the bit configuration before color number reassignment in FIG. 13 and the bit configuration after color number reassignment in FIG. 16, bit on (=
While the state of 1) is distributed to each plane, bit-on is concentrated on the 0 plane and the 1 plane after reassignment.

Moreover, all three planes are bit off (= 0). This is because the color numbers that are frequently used are renumbered to smaller ones, so 0, 1
I concentrated on the plane. As a result, a state was created in which data compression was easy.

FIG. 17 is a flow chart showing the above processing. However, FIG. 17 shows an example in which character data is read from a file and the frequency of color numbers of all character data is chucked and re-attached. 13 to 16 deal with only one character data so that the color renumbering algorithm is easier to understand). Therefore, it is a flow chart for a more general case.

In FIG. 17, the character data file is read twice. In the first loop, the frequency of the color use frequency table (see FIG. 18) is calculated. Based on this result, the frequency of use in the color number frequency table is sorted in descending order. Based on the sorted result, the new color number is further changed.

The table at the bottom of FIG. 18 shows the result. As you can see from this result, the new color number is
It is in the same column as the color number before sorting. Therefore, actually, the new color number does not need to be held in the table, and can be substituted by the table index.

If the character data is read again in a later loop, a new color number is set, and the result is zero-compressed and written into the new character data, an efficiently reduced file can be obtained.

Although the CG color code (color pattern) is not taken into consideration in the table of FIG. 18, when data including different CG color codes is included, a color number use frequency table is created in consideration of this. I need to put it. Even if the new color number item is deleted from the table,
The processing of FIG. 17 can be performed. It is included here to clarify the meaning of the new color number.

[0044]

The image data is very large and requires a large storage area. Therefore, data compression is an essential operation when saving data in the auxiliary storage device. However, until now, the bits were scattered on each surface (plane) in character data, etc., so the effect of zero compression was not obtained as expected.

In the present invention, by adopting a method of re-assigning small color numbers in descending order of frequency of use, the bit-on planes can be concentrated on the 0 and 1 planes, and the data compression can be performed efficiently. As a result, a great effect was achieved in terms of effective use of the storage area.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a computer display screen that manages a screen with a background and sprites.

FIG. 2 is an explanatory diagram of addresses in a background attribute (BAT) of a character on a virtual screen.

FIG. 3 is an explanatory diagram showing the positions and contents of background attributes (BAT) in VRAM.

FIG. 4 Background attribute table (B
It is an explanatory view showing the composition of AT).

FIG. 5: Character generator (CG) in VRAM
It is explanatory drawing which shows the position and content.

FIG. 6 is an explanatory diagram of background display control.

FIG. 7 is an explanatory diagram of background display control.

FIG. 8 is an explanatory diagram of background display control.

FIG. 9 is an explanatory diagram of background display control.

FIG. 10 is an explanatory diagram of background video output.

FIG. 11 is a diagram showing a configuration of a BAT and a character generator (CG) on a VRAM.

FIG. 12: Color palette (color table VRAM)
It is a figure which shows the relationship between the video data output port (VD0-VD8).

FIG. 13 is a diagram showing a bit configuration of each plane of a character generator (CG) before renumbering of color numbers.

FIG. 14 is a diagram showing one unit of a character in hexadecimal notation of a character generator (CG) before renumbering of color numbers.

FIG. 15 is a diagram showing one unit of a character in hexadecimal notation of the character generator (CG) after reassigning color numbers.

FIG. 16 is a diagram showing a bit configuration of each plane of the character generator (CG) after renumbering of color numbers.

FIG. 17 is a flowchart of color number reassignment processing according to the present invention.

FIG. 18 is a diagram showing a configuration of a color number use frequency table in the present invention.

Front page continuation (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location G09G 5/02 9175-5G 5/36 9177-5G H04N 1/41 C 9070-5C

Claims (1)

[Claims] 1. A color number of each dot of the pattern in a pattern determined by data defined by a plurality of planes for designating a color number of each dot used in a computer device that forms a screen by a set of patterns The pattern data forming method is characterized in that the frequency of use of color numbers is calculated for data defined by a plurality of planes to specify, and small color numbers are reassigned in descending order of frequency of use.