JP3468631B2 - Mirage polygon control circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirage polygon control circuit capable of easily displaying a mirage for a far object on a CG screen.

[0002]

2. Description of the Related Art In a 3D game machine, a three-dimensional image is displayed on the screen by displaying it in perspective, and the appearance of the object may be different depending on whether it is near or far. For example, on asphalt, such as on a hot day, distant objects sway and fluctuate due to the air warmed by heat, and they may look like a mirage without retaining their shape. When the mirage is expressed in a 3D game, it may be possible to display it by a proper calculation method, but in order to accurately calculate and display the mirage, the calculation formula to be calculated becomes complicated and it takes time to calculate. Further, since it is necessary to rewrite the data for each frame, the load on the CPU is increased and an extra memory circuit is required.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a mirage polygon control circuit for a distant object with a simple circuit configuration and capable of artificially creating a mirage.

[0004]

In order to achieve the above object, the mirage polygon control circuit according to the present invention comprises a CPU
In the polygon control circuit, which performs coordinate conversion or the like for displaying a three-dimensional image in the geometry circuit based on the data from the polygon data memory circuit and writes each polygon in the frame buffer by the image synthesizing circuit having the line zoom means, the CPU is When the mirage display is determined, the dot display position of each line of the line zoom means according to the perspective of the image display portion, with respect to the coordinates obtained by calculation,
It is configured such that the data is shifted laterally in dot units and written in the frame buffer. In the above configuration,
The lines to be shifted in the horizontal direction of the line zoom means are arranged every other line.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an example of an image including a mirage display formed by a mirage polygon control circuit according to the present invention. Frame buffer 1 (CRT1
The screen displayed in 0) is a landscape in which roads continue in the distance, and the cube 2 placed closest can be clearly seen. The cube 3 which is relatively far away is displayed so as to appear slightly fluctuated by the warmed air. The cube 4 located further away is displayed so that it looks fluctuating in the mirage so that the shape cannot be confirmed, and the edges and ridges of the road that are visible in the distance are also displayed.

FIG. 2 is a diagram showing an example of the entire circuit configuration of a game machine to which the mirage polygon control circuit according to the present invention is applied. When a coin is inserted into the coin related device 17, it is transmitted to the CPU 8 via the input / output control device 15,
The game is launched. The backup memory 19 stores set values of the number of coins, the number of plays, and the difficulty level. CPU
Reference numeral 8 reads a program for controlling the entire game from the program ROM 13, controls the mirage polygon control circuit 5 according to the read program, and displays the initial screen as C.
Display on RT10. Also, the three-dimensional coordinates of the player in the game space are calculated based on the signal from the operation device 18. Further, situation data such as the player hitting an enemy's bullet or colliding with another object is calculated. CPU8
When it is determined that an environment condition (when the temperature of the background becomes high) that creates a mirage for a distant object is sent, the information is sent to the mirage polygon control circuit.

The work RAM 12 is an area used when the CPU 8 performs the above calculation. The communication RAM 20 stores instructions of the CPU 8 regarding sound, and is used when the CPU 8 confirms the sound condition. Sound is generated by the sound system circuit 21, and the sound is output from the speaker 22. The screen control circuit 6 specifies the background image to be displayed from the three-dimensional coordinates of the player based on the information from the CPU 8, and reads the address of the character forming the specified background image from the screen memory 11. Screen character R connected to the screen control circuit 6
The OM 14 stores characters (16 × 16 dots) that form a polygon background image, and the character at the address read from the screen memory 11 is read.

The three-dimensional model displayed on the screen is expressed as a collection of polygons. The polygon data memory circuit 7 stores the three-dimensional coordinates representing the reference points of this three-dimensional model and the polygons forming the three-dimensional model. Each vertex coordinate (3
(Dimensional coordinates) are stored in the world coordinate system. The frame buffer 1 connected to the mirage polygon control circuit 5 is a bit map type memory circuit in which the polygons converted into two dimensions are written. Color RAM / DAC
Reference numeral 9 generates RGB data (digital) based on the color code and palette number, converts the RGB data into analog and sends it to the CRT 10.

FIG. 3 is a block diagram showing details of the Mirage polygon control circuit of FIG. The mirage polygon control circuit 5 includes a geometry circuit 23 and an image composition circuit 27.
It is composed of The geometry circuit 23 includes a three-dimensional operation circuit 24, a perspective transformation circuit 25, and a clipping circuit 26. The three-dimensional arithmetic circuit 24 converts the three-dimensional coordinates of the polygon data into a viewpoint coordinate system whose origin is the player. The perspective transformation circuit 25 transforms the three-dimensional coordinates into two-dimensional coordinates on the screen. Further, the clipping circuit 26 determines whether or not the perspective-transformed polygons enter the screen.

FIG. 4 is a block diagram showing details of the image composition circuit of FIG. The image synthesizing circuit 27 performs image synthesizing for writing each polygon in the frame buffer 1. The rendering circuit 28, the line zoom circuit 29,
It is composed of a palette memory circuit (line RAM) 30, a Z buffer circuit 31, and a texture memory circuit. The present invention is characterized by a line zoom circuit 29 and a palette memory circuit 30 which are line zoom means.

FIG. 5 is a diagram for explaining the details of the palette memory circuit. FIG. 5A shows an example of the palette memory circuit in the case of 2D, and FIG. 5B shows the palette memory circuit in the present invention. In the case of (a), 1 per line
One memory is associated with one memory, and one line of pallet memory is formed by all lines (254 lines). The pallet memory circuit 30 of the present invention in (b) is configured by providing a large number of 2D pallet memory portions in the depth direction. This is because, if the mirage is generated at a distance, the fluctuation becomes larger and the data value needs to be changed with respect to the depth. When the number of palette memory units is the same as the number of Z buffer stages, the movement value and zoom value in the X direction are stored in each palette memory unit for each depth direction (Z). The contents of the palette memory circuit 30 are written in advance by the CPU 8, and the line zoom circuit 29 shifts or expands / contracts every other line based on the data in the palette memory section of the palette memory circuit 30.

FIG. 6 is a diagram showing an example of set values in the palette memory unit (line RAM) for each Z value. Z value = A
In the palette memory part of
Direction movement values a, b, c ... and zoom values o, p, q
・ ・ Is stored. Similarly, other Z values = B, C ...
The above data is also stored in the pallet memory section of. Hereinafter, the operation when the mirage polygon control circuit generates a mirage will be described. When the geometry circuit 23 of the mirage polygon control circuit 5 completes the conversion of the three-dimensional coordinates, it sends the data to the image composition circuit 27. The rendering circuit 28 of the image composition circuit 27 performs a process of writing this data in the frame buffer 1. The line zoom circuit 29 reads the Z value in the data sent through the rendering circuit 28, accesses the palette memory section of the palette memory circuit 30 corresponding to the Z value, and moves the X direction movement value for each line. And get the zoom value. The rendering circuit 28 performs the following operation based on this value.

For example, it is assumed that there is data of three vertices whose three-dimensional coordinates have been converted. Then, if these are connected, a triangle as shown at the left end of FIG. 7 can be drawn. The connected line is calculated by the rendering circuit 28. If the calculated result is written in the frame buffer 1 as it is, the result is as shown in FIG. The present invention, in this operation,
Depending on the data read from the palette memory circuit 30, it is laterally displaced or expanded / contracted as shown in FIG. The horizontal shift is expressed by addition / subtraction to / from the X coordinate, and the expansion / contraction is expressed by repeating (extending) and skipping (compressing) the X coordinate. By operating in this way, a mirage can be represented.

The color painting is determined by the rendering circuit 28 as 3
This is done between the intersections of the lines connecting the vertices and the horizontal lines. The left intersection is the painting start point and the right intersection is the painting end point.
The line zoom circuit 29 performs addition / subtraction or shifts on the data of both points based on the data read from the palette memory unit. Where Z at start and end
When the original polygon is extended in the horizontal direction from the end point, the drawing time is slightly longer than when the line zoom is not performed, but when it is contracted, the drawing time ends earlier than when the line zoom is not performed. Note that this circuit does not change with or without texture memory. Further, it is also possible to paint each line with one color (for example, white) by the data of the palette memory unit.

Next, a case where a sorting circuit is used will be described. The Z buffer circuit is not used when the sorting circuit is used. Usually, the distant polygons are written in the frame buffer in order, so it is necessary to give the palette a designation such as shifting to this polygon and shifting from this point to this point. The operation is almost the same as when the Z buffer is used, but since depth information does not exist in the same polygon, it is not possible to make an expression that the way of shaking changes depending on the point in the polygon.

FIG. 8 is a diagram showing an example of a mirage that is shifted by 1 dot and 3 dots with respect to the correct coordinates calculated by the CPU. When the coordinates are correct, that is, when the mirage is not displayed, the vertical line has no fluctuation as shown in (a). (B) is a slightly fluctuating mirage, shifted by one dot. (C) is a large fluctuating mirage, shifted by 3 dots each.

[0017]

As described above, the present invention provides a CPU.
When the mirage display is determined, the dot display position of each line of the line zoom means is shifted laterally in dot units in accordance with the perspective of the image display portion, and written in the frame buffer. It is the one. Therefore, there is an effect that a pseudo mirage screen can be configured with a simple circuit operation.

[Brief description of drawings]

FIG. 1 is a diagram showing an example image including a mirage display made with a mirage polygon control circuit according to the present invention.

FIG. 2 is a diagram showing an example of the entire circuit configuration of a game machine to which a mirage polygon control circuit according to the present invention is applied.

FIG. 3 is a block diagram showing details of the Mirage polygon control circuit of FIG.

FIG. 4 is a block diagram showing details of the image composition circuit of FIG.

FIG. 5 is a diagram for explaining details of a palette memory circuit.

FIG. 6 is a palette memory for each Z value (line RA
It is a figure which shows the example of a setting value of M).

FIG. 7 is a diagram for explaining an operation example of displaying a mirage of a line zoom circuit.

FIG. 8 is a diagram showing an example of a mirage that is shifted by 1 dot and by 3 dots with respect to the regular coordinates calculated by the CPU.

[Explanation of symbols]

1 ... Frame buffer 2, 3, 4 ... Cube 5: Polygon control circuit 7 ... Polygon data memory 8 ... CPU 9 ... Color RAM (DAC) 10 ... CRT 11 ... Screen memory circuit 12 ... Work RAM 13 ... Program ROM 14 ... Screen character ROM 15 ... Input / output control device 16 ... RS-232-C 17 ... Coin related device 18 ... Operating device 19 ... Backup memory circuit 20 ... Communication RAM 21 ... Sound system 22 ... speaker 23 ... Geometry circuit 24 ... Three-dimensional arithmetic circuit 25 ... Perspective conversion circuit 26 ... Clipping circuit 27 ... Image synthesis circuit 28 ... Rendering circuit 29 ... Line zoom circuit 30 ... Palette memory circuit 31 ... Z buffer circuit 32 ... Texture memory circuit

Claims (2)

(57) [Claims] 1. A polygon control in which a geometry circuit performs coordinate conversion or the like for displaying a three-dimensional image based on data from a CPU and a polygon data memory circuit, and an image synthesizing circuit having a line zoom means writes each polygon in a frame buffer. In the circuit, when the CPU determines the mirage display, the dot display position of each line of the line zoom means is shifted in the horizontal direction in dot units with respect to the calculated coordinates according to the perspective of the image display portion. Mirage polygon control circuit characterized by writing to a frame buffer. 2. The mirage polygon control circuit according to claim 1, wherein the lines to be shifted in the horizontal direction of the line zoom means are arranged every other line.