JPH07210142A - Method for displaying picture - Google Patents

Abstract

PURPOSE:To save pallets and to make it possible to display colors more than the number of colors specified by color pallets on the same screen by specifying a prescribed character by a transparent color and changing the color specification of a base color in each raster by using raster interruption.. CONSTITUTION:A part occupying a large part of the whole screen is a expressed by raster color change. Namely white is specified as a base color at first, and then blue is gradually increased. Other characters are plotted on the base color. A sky e.g. is changed like blue, red and black with the lapse of time and expressed without using pallets, so that parts contacting with the sky (base color) are specified by transparent colors. A mountain character is plotted by green and its background is specified by a transparent color. Thereby the transparent color part becomes the same as the base color and the color of the part is changed in accordance with the change of the base color. in this operation, original pictures are expressed by the pallets of numerals written in circular marks and the number of pallets can be saved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen display method in a computer device for displaying a screen by superimposing a character and a sprite image on a base color.

[0002]

2. Description of the Related Art Conventionally, in a general home computer game machine, a moving object such as a background or characters displayed in order to increase processing speed is managed by a block of dots called a character or sprite, and a base color is used. It has a function of displaying a screen by superimposing a character and a sprite image on top.

Here, a device in which a character has a structure of 8 × 8 dots and a sprite has a structure of 16 × 16 dots will be described as an example. In such an apparatus, there are many cases in which the number of colors that can be simultaneously expressed is small due to hardware restrictions. For example, in a certain model, 16 palettes of 16 colors (= 16 × 16
= 256 colors), and in another model, 16 palettes with 8 palettes (1
6 × 8 = 128 colors). Explain why there are such restrictions.

FIG. 1 is a block diagram of a VRAM of an example game machine. The background is VRAM BAT (background attribute table) and CG (character
It is managed by a generator, and its contents are displayed on a screen such as a CRT. FIG. 1 shows the structure and connection of individual records of BAT and CG.

The BAT record consists of two items, CG color and character code. The CG color indicates the block number of the color palette. The character code indicates the CG address, and the CG record position can be known from this address. A CG is an area expressing characters and a background image displayed on the screen, and a CG record has a graphic pattern of 8 × 8 dots formed on four sides. These planes are called CH0, CH1, CH2, CH3 in that order.

The CG has a four-sided structure, and a bit value (0 or 1) of a dot having the same vertical and horizontal coordinate values indicates the color information number in the palette.

BAT CG color and CG CH0-CH
3 is set in the shift register in the video display controller VDC as shown in FIG. This content is further sent to the video data output ports VD0 to VD8. CG color is set to VD4 to VD7, and CH0 to CH3 are set to VD0 to VD3, respectively. VD0-VD
Data of 8 is color palette (color table RAM)
And converted into color image data and sent to the video color encoder.

Further, when the VCE converts the RGB signals for TV images and the video color signals and transfers them 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, since VD8 is set to 0, the background block can be selected from the values of VD4 to VD7, and the dot color in the block can be extracted from the values of VD0 to VD3. VD4-V
The original value of D7 is CG color, VD0 to VD
That of 3 is CH0-CH3.

Since the above processing is automatically performed by the system of the computer game device, the V
All you have to do is prepare the RAM and color palette in advance.

As shown in FIG. 3, the C of the BAT record
The G color is used to select any one of the 16 blocks in the color palette. That is, CG
By changing the color value, the color pattern can be changed.

For example, BAT has CG color of 5, CG
If the value of CH0 to CH3 is 3, the color information 3 of the block 5 in the color palette is displayed as the color of this dot.

The values of CH0 to 3 of CG are calculated by binary number calculation. The value 3 is CH0-3 is 1,1,
This is the result calculated as 1 · 2 ⁰ + 1 · 2 ¹ + ⁰ · 2 ² + 0 · 2 ^{3 in the} 0,0 configuration.

The color restrictions come from this color palette. That is, the number of blocks in the palette is 16 and the number of pieces of color information in each block is 16, which is the number of colors that can be simultaneously expressed by this system.

Sprites are treated in the same manner as characters, and SAT (sprite attribute table) and SG (sprite generator) in VRAM are used.
Managed by. Here, since the content is related to the present invention, the background will be mainly described. However, the display colors are basically the same.

Recently, some personal computers have multi-color expressions of tens of thousands of colors, but generally, 16 colors out of 256 colors are selected, or 8 colors are selected. One of the reasons is the problem of the memory (the memory for the color palette increases as the display color increases), and the other one is the display function (the display function of the color generator or the display).

In the case of the home-use game machine exemplified here, since one pallet (block) is designated for one character, one character can represent 16 colors. However, the number of blocks prepared in the color palette is 16
Therefore, the maximum expression color is naturally limited.

[0018]

On the other hand, recently, in order to express a more realistic image, multicolor expression has been required. In particular, what was previously represented by one color, such as the color of the sky or the color of the sea, is now becoming more and more multicolored to produce subtle colors. For example, the color of the daytime sky is
It is not all blue, but the upper one is whitish, like a color change such that it becomes blue as it approaches the horizon.

Up until now, one or more palettes have been used to produce this sky color. Therefore, there has been a problem that the number of palettes for other background expressions is reduced. Figure 4
Is an example of using one palette for the entire background color.
For this reason, other backgrounds have to be represented by one less palette.

Traditionally, several palettes have been used for the entire background. Therefore, an object of the present invention is to represent the entire background color by some method and secure the number of palettes for other backgrounds, that is, to save palettes.

[0021]

The computer game device used in the method of the present invention has a color generator function for controlling the color displayed on the screen, and the color of the screen is adjusted by sending a control signal to this. be able to.

There is also a base color, and the color of the entire screen can be instantly changed. For example,
From blue to red. You don't have to use a color palette for this. However, it is difficult to express in multiple colors.

On the other hand, a transparent color can be designated for the character and the sprite, and the portion for which the transparent color is designated can be seen through, and the color of the base color is displayed as it is.

The present invention utilizes the above functions to represent the entire background without using a palette. That is, by using the function of the color generator, the color designation as the base color is changed for each raster by using the raster interruption. Figure 5 shows the situation, the first is color A,
I changed to color B from the middle. Therefore, the entire screen is divided into a color A and a color B at the top and bottom of the screen.

As described above, FIG. 6 shows the background expression when the present invention is used in correspondence with FIG. As can be seen from the example of FIG. 5, the base color is not always 1
Not a color. The figure shows that one extra palette is directed to another background representation.

[0026]

EXAMPLE As an example of the present invention, consider the case of expressing a picture as shown in FIG. The picture depicts moving creatures such as the sky, clouds, trees, mountains, the earth, snakes and monsters. The most important background here is the sky. This is because it occupies a large part of the entire screen. Previously, this part was also represented by characters, and at least one palette was used.

In the present invention, this portion is expressed using raster color change. That is, white is designated as the base color first, and blue is gradually increased. However, in the computer device used in this embodiment, the color is changed every 16 rasters as shown in FIG.

Other characters are drawn on this base color. A character represents an object with 8 × 8 dots. However, even if the pictures are different, if the type of color used (16 colors in the apparatus of the embodiment) is the same, the same palette can be used. For example, if the cloud can be expressed in two colors, white and gray, the palettes (block numbers of the color palette in the program) used can be the same even if the characters are different.

When the character is drawn on the base color,
The base color will be erased. Therefore, when the base color is changed, the expression of the base color may not be reflected in the picture of the character. For example, the sky changes blue, red, and black from day to evening, and at night and time. In order to express it without using a palette,
Specify the part that contacts the sky (base color) with a transparent color.

The transparent color is a color that can be seen through when it is superimposed on another character or the base color. For example, as shown in the example of FIG. 9, mountains are drawn in green on the character, and the background is designated as a transparent color. By doing so, the transparent color part becomes the same as the base color, so if the base color changes, this part also changes instantly.

By the above operation, the original image shown in FIG. 7 can be represented by a palette as shown in FIG. 10 (numerical values in circles represent the palette). In this example, one pallet has been saved.

It is also possible to save pallets. In the example of FIG. 10, the flat land portion also has a uniform spread in the horizontal direction, so the pallet 4 is used for the flat ground, but it is also possible to change to the base color.

This is because, for example, a raster interrupt may be inserted at the boundary between a mountain and a flat land, and a raster change may be performed when a screen is displayed to change to a flat ground color (green or earth color). That would save an extra pallet. However, if you want to change the color in the horizontal direction, this method cannot be used.

[0034]

According to the method of the present invention, it is possible to save the palette and to display more than the number of colors designated by the color palette on the same screen.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a BAT and a CG on a VRAM of a conventional computer game device.

FIG. 2 shows a BA in a conventional computer game device.
FIG. 7 is a diagram showing a flow of control and data from T and CG to setting a dot pattern in a shift register.

FIG. 3 is a diagram showing a relationship between a color palette (color table VRAM) and video data output ports (VD0-VD8) in a conventional computer game device.

FIG. 4 is an explanatory diagram of representation of an object by a conventional method.

FIG. 5 conceptually illustrates a color change due to a raster interrupt.

FIG. 6 is a representation of the background according to the method of the present invention.

FIG. 7 is an original image to be expressed.

FIG. 8 is an explanatory diagram of an expression of a sky by a base color.

FIG. 9 is an explanatory diagram of transparent colors.

FIG. 10 is a diagram showing an example in which the original image of FIG. 6 is used for the present invention and palettes are sorted.

Claims (3)

[Claims] 1. A method of displaying a screen by superimposing a background screen composed of a character and a sprite screen composed of a sprite image on a base color, and at least a transparent color can be designated for the character. A screen display method using a computer device, wherein a predetermined character is designated as a transparent color, and a raster interrupt is used to change the designation of a base color for each raster. 2. A method of displaying a screen by superimposing a background screen composed of characters and a sprite screen composed of sprite images on a base color, and at least a transparent color can be designated for the sprite. A screen display method using a computer device, wherein a predetermined sprite is designated as a transparent color, and a raster interrupt is used to change the designation of a base color for each raster. 3. A method of displaying a screen by superimposing a background screen composed of characters and a sprite screen composed of sprite images on a base color, and a transparent color can be designated for the characters and sprites. In a screen display method using a computer device, a predetermined character or sprite is designated with a transparent color, and a raster interrupt is used to change the color designation of a base color for each raster.