JPH0244077B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display control device for a scanning display, and more particularly to an improvement in a display control device for displaying three-dimensionally changing lines on the screen of a scanning display.

Recently, in game centers etc., Cathode
Video game devices are installed that play various games using a scanning display such as a Ray Tube (hereinafter referred to as CRT) display. Conventional video game devices have had the problem of being limited to two-dimensional displays and not capable of three-dimensional displays. For this reason, conventional video game devices have the problem that the game content is limited to two-dimensional games and lacks fun. Therefore, in the video industry,
There is a demand for the development of a technology that can display three-dimensional or three-dimensional images using a flat display device such as a CRT display.

By the way, in the past, as a technology for displaying three-dimensional images using a scanning display, there was
``Electronic circuit device for pattern generation'' described in Japanese Patent No. 51644 is known. However, the invention described in Japanese Patent Application Laid-Open No. 54-54644 was developed for the purpose of training pilots, and displays surfaces or objects three-dimensionally. However, since this has an extremely complicated configuration, it has the problem of being extremely expensive, costing several hundred million yen. Such previously proposed inventions are: 1.
This method could not be applied to video game devices that had to be manufactured for a price of several hundred thousand yen. In addition, in the case of displaying a surface or an object three-dimensionally, the previously proposed invention stores boundary line data of a surface in a large number of counters or memories in order to display a surface surrounded by a plurality of boundary lines. Therefore, if you try to reduce the price by reducing the number of memories, the surface will be undesirably divided at the intersection of multiple boundary lines, and a different object or surface than the one you want to display will be displayed. Contains problems.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a display control device for a scanning type display that is relatively simple in structure and inexpensive and can perform three-dimensional display using a scanning type display.

In summary, the present invention provides a method for displaying a projected line on the screen of a scanning display based on the coordinate data and slope data of the line.
When determining the intersection position data where the line intersects with the horizontal scanning line and writing the data identifying the type of line to be displayed at the intersection into the storage means as the data of the line to be displayed in one horizontal scanning period of the scanning display. , the intersection position data is used as a write address.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an outline of the invention. In the configuration, the display control device 10 of this embodiment includes a viewpoint data generator 12, a data processor 13, a computer (or microcomputer) 14, in order to display three-dimensionally changing lines on the scanning display 11. It includes a clock generator 15 and an image generator 20.

As the scanning display 11, for example, a raster scan type CRT display is used. In the following embodiments, a case will be described in which a CRT display capable of color display is used to display various lines in color.

The viewpoint data generation device 12 includes an operation section 12a.
and a simulation computer 12b. The operation unit 12a provides the simulation computer 12b with data for changing the display position of a moving object (for example, an aircraft) serving as a viewpoint according to the player's operation. The simulation computer 12b generates viewpoint data, for example, aircraft flight data, based on the operating state of the operating section 12a, and provides it to the data processor 13. Here, the flight data of the aircraft includes position data and attitude data of the aircraft whose display position is changed by the player's operation.

The computer 14 includes memory and a central processing unit (CPU). This computer 14
controls for writing model data of a visual object model stored in an external storage device (not shown) into the memory included in the data processor 13, and writes model data based on pre-stored data. Performs control to change the display position.

The clock generator 15 generates clock signals for the operation of the scanning display 11, data processor 13, and image generator 20.

The data processor 13 allows an image generator 20 (described later) to display three-dimensional lines on the scanning display 11 based on viewpoint data provided from the simulation computer 12b and model data provided from the computer 14. The image generator 20 is supplied with the data necessary to generate the video signal. Here, the calculation performed by the data processor 13 is to determine boundary line data with respect to the surface of the model from two coordinates: viewpoint coordinates based on viewpoint data and model coordinates based on model data. There are two calculations for this boundary line data: calculation of the contour line and calculation of whether the surface surrounded by the contour line is visible or invisible. Calculation of such boundary line data is described in Japanese Patent Application Laid-open No. 1983-
The same calculation method as No. 51644 is used.

Therefore, in the following explanation, a case in which coordinate transformation is performed from viewpoint data and model data will be briefly explained within the scope necessary for understanding the present invention.

In order to draw a model in a three-dimensional absolute coordinate space, the computer 14 calculates an equation for each contour of the model in absolute coordinates, and draws a perpendicular line from the origin of the absolute coordinates to the contour of each model. The coordinates (X, Y, Z) of the intersection and the direction cosine of each contour are stored in memory. In this case, for one line, three-dimensional intersection coordinates and cosine data, that is, six pieces of data are required. Model data is calculated based on these data. Therefore, the computer 14 stores model coordinates when drawing a model on absolute coordinates, and provides data for each model to the data processor 13.
On the other hand, assuming coordinates with the viewpoint as the origin (ie, viewpoint coordinates), the data processor 13 performs a calculation, that is, coordinate transformation, to replace the absolute coordinates of the model space with the viewpoint coordinates. in this case,
If the viewpoint moves, the display position of the model relative to the viewpoint changes, so it is necessary to perform coordinate transformation for each screen (in other words, for each frame of a scanning display). Furthermore, if the position of the viewpoint is moved little by little, the model appears to move. In addition,
The calculation of each of the plurality of lines representing the contour of the model must be performed within the time of one frame of the scanning display 11, that is, within 1/30 second.
In this case, the data processor 13 of this embodiment
includes two calculation CPUs and one control CPU.
Since 16 lines can be calculated in one frame considering the general processing speed of a calculation CPU, 32 lines can be calculated in one frame time. It goes without saying that by increasing the number of calculation CPUs included in the data processor 13, the number of lines that can be displayed in one frame can be increased.

2A to 2C are diagrams schematically showing the display mode of the scanning display 11 for explaining the principle of the present invention. In particular, FIG. 2A shows one line on the screen of the scanning display 11. 2B and 2C show lines existing in a three-dimensional space beyond the coordinates on the screen of the scanning display 11, that is, the outline. FIG. 3 is a diagram schematically showing processing when

Next, the principle of the present invention will be briefly explained with reference to FIGS. 1 to 2C. The coordinate transformation data obtained by the data processor 13 as described above is data of lines existing in a three-dimensional space. However, the scanning display 11 can only display two-dimensional coordinates, and moreover, the display device is of a raster scan type. Therefore, in the line data obtained by the data processor 13, it is necessary to replace the upper left of the display screen of the scanning display 11 with the origin (xO, yO) of the two-dimensional display coordinates. Therefore, the data processor 13 obtains boundary line data that matches the two-dimensional display coordinates from the previously obtained line data of the contour line of the model in the following manner. That is, the scanning display 11
When the upper left of the screen is the origin of the two-dimensional display coordinates (xO, yO), the point where the line representing the model outline cuts the screen outline (especially the upper, left, or right side shown in Figure 2A) is the point ( In other words, the coordinate data (AHN,
AVN) and slope data (△x, △y).
Here, the data included in the coordinate data of the cutting point
AHN is the horizontal position of the display coordinates, in other words, the horizontal axis (x This is the position data of the starting point of the axis). The data AVN is the vertical position of the point where the line to be displayed intersects the screen contour, ie the vertical position of the electron beam. For example, if the screen of the scanning display 11 has 256 dots in the horizontal direction and 256 dots in the vertical direction (that is, 256 horizontal scanning lines), the horizontal axis or horizontal position data consists of x=0 to 255, Vertical or vertical position data is y
= Consists of 0 to 255. For example, if a line displayed on the screen intersects the left side of the screen outline as shown in Figure 2A, then AHN=0,
AVN=0-255. Also, if the line displayed on the screen intersects the right side, then AHN=
255, AVN=0 to 255. Also, if the line displayed on the screen intersects the top edge,
AHN=0 to 255, AVN=0.

By the way, if the line representing the outline of the model that exists in the three-dimensional model coordinates is not within the field of view, it will not be displayed on the screen and will not be displayed on the screen in Figure 2B or 2C.
As shown in the figure, it will exist outside the outline of the screen. In this case, the line existing outside the screen is considered to be on the right or left side of the screen outline.

By the way, when displaying the outline of a model on a scanning display 11 using a progressive scanning method, the vertical unit Δy is the width of one horizontal scanning line (that is, Δy=1).
becomes. Therefore, the tilt data BN can be expressed only by Δx, which indicates how far the horizontal position has moved in the horizontal direction for each horizontal scanning line. Further, when the scanning display 11 is of an interlaced scanning type, the vertical unit Δy is 2.

Note that the line displayed on the screen does not necessarily cut the left side, right side, or top side of the screen outline; it cuts the left side,
It may intersect with the right side or the top side. In that case, it is necessary to erase unnecessary parts of the lines. Therefore, the data processor 13 actually uses cut point coordinate data (AHN, AVN and slope data BN).
In addition, a signal indicating whether the line is visible or invisible (eg, a signal with visible as logic "1" and invisible as logic "0") is generated. In this case, a signal is added to the line displayed on the screen to indicate that the part from the cut point on the left, right, or top side to the vertical position to be displayed is invisible, and the part to be displayed is visible. A signal indicating that this is the case will be added.

Next, details of the image generator 20, which is a feature of the present invention, will be explained.

FIG. 3 is a detailed circuit diagram of the image generator 20. In the configuration, the data processor 13
is the boundary line data of a plurality of lines to be displayed in the next frame during the vertical blanking period of the scanning display 11, that is, the cutting point position data.
AHN, AVN and slope data are given to the random access memory (hereinafter referred to as RAM) 21a, and write address data (WA) is given to the selector 22.
give to a. The RAM 21a has a storage capacity capable of storing boundary line data of the maximum number of lines to be displayed in one frame. The selector 22a provides the write address given from the data processor 13 to the RAM 21a during the vertical blanking period, and provides the horizontal position data (HA) as read address data (RA) to the RAM 21a during the horizontal scanning period. Here, the horizontal position data refers to the position where the electron beam of the scanning display 11 is horizontally scanning. The horizontal position data is generated by a horizontal counter (not shown) that performs counting operations in synchronization with the horizontal scanning of the electron beam. Note that in the following description, the horizontal position will be referred to as a horizontal address. RAM2
1a is for multiple lines to be displayed in one frame (up to 32
Cut point position data (AHN,
AVN) and tilt data (BN) are stored, and the stored contents are sequentially read out in synchronization with the horizontal address for each horizontal scan of the electron beam.
Cut point position data read from RAM21a
AHN, AVN, and slope data BN are applied to and loaded into corresponding registers 23b, 23a, and 23c, respectively. Register 23c is slope data BN
is given to the adder 24. The register 23b provides horizontal cut point position data AHN to the selector 22b. Register 23a is vertical cut point position data.
AVN is given to the comparator 25. The comparator 25 has
The vertical position of the electron beam, ie vertical position data (VA), is given. Here, the vertical position data is a count value of a vertical synchronization counter for specifying the vertical position of the electron beam, and will be referred to as a vertical address in the following explanation. Comparator 25 detects that vertical address VA has exceeded data AVN, and provides a signal representing the detected state to selector 22b. The selector 22b is
When the comparator 25 does not derive a detection signal, the contents (AHN) of the register 23b are given to the RAM 21b,
When the comparator 25 derives the detection signal, the adder 24
The count value is given to the RAM 21b. Here, the adder 24 adds the contents (BN) of the register 23c and the contents (HCN) of the register 23d at fixed time intervals during the horizontal scanning period. This fixed time is equal to the time equivalent to one horizontal scanning period divided by the maximum number of lines (32) that can be displayed in one frame. Here, the data HCN is horizontal position data where a line to be displayed on the screen intersects each horizontal scanning line, ie, intersection position data.

The RAM 21b includes a storage area for storing data HCN for each of the maximum number of lines that can be displayed in one frame. A horizontal address (HA) is given to this RAM 21b as a write address (WA) and a read address (RA), and
A write pulse (WP) is applied from the write control circuit 26a. The RAM 21b stores intersection position data HCN that intersects with the horizontal scanning line for each line to be displayed on the screen.

Intersection position data read from RAM21b
HCN is applied to register 23d and selector 22c. The selector 22c is further given a horizontal address HA. The selector 22c supplies the intersection position data HCN read from the RAM 21b as a write address to the RAM 21c during the horizontal blanking signal period, and supplies the horizontal address as a read address to the RAM 21c during the horizontal scanning period.
Give to 1c.

Therefore, RAM 21a, selectors 22a and 22b, registers 23a to 23d, adder 2
4 and the comparator 25 function as an intersection point calculation means for determining the intersection point where the outline or line of the model to be displayed intersects with the horizontal scanning line. and,
The RAM 21b stores the intersection position data obtained by the intersection position calculation means, and functions to designate the write address of the RAM 21c using the intersection position data.

The RAM 21c is given data for identifying the type of line (or line representing the contour of the model) from a read-only memory (hereinafter referred to as ROM) 27, which is an example of second storage means. This ROM 27 stores data that identifies the type of line for each of a plurality of lines that can be displayed in one frame. For example, if the scanning display 11 is capable of color display, the ROM 27 stores color codes corresponding to the colors to be displayed for each type of line. Note that if the scanning display 11 is a black and white television,
The ROM 27 stores a brightness code in place of the color code. The read address of this ROM 27 is designated by a horizontal address. moreover,
A write pulse is applied to the RAM 21c from the write circuit 26b. Therefore, the RAM 21c sequentially stores line type identification data read from the ROM 27 in synchronization with the write pulse at the address specified by the intersection position data HCN with the horizontal scanning line to be displayed. It is.

The data read from the RAM 21c, that is, the color code to be displayed at the intersection of the line to be displayed on the screen and the horizontal scanning line, is stored in the register 23.
e and is loaded. The color code loaded into the register 23e is given to the color generation circuit 28. The color generation circuit 28 generates a video signal containing a color signal for color display on the scanning display 11 based on the color code, and supplies it to the scanning display 11.

4A to 4C are circuit diagrams schematically showing the flow of data to explain the operation of the present invention. Particularly, FIG. 4A shows the case of the vertical blanking signal period, and FIG. 4B shows the case of the vertical blanking signal period. The case of the horizontal scanning period is shown, and FIG. 4C shows the case of the horizontal blanking signal period. Note that in the figure, white lines indicate the flow of data, and solid lines indicate a circuit connection state in which no data flows.

FIG. 5 is a diagram schematically showing the display state of the scanning display 11 for explaining the operation of the present invention. For example, the first line LN1 intersects the right side of the screen, the cut point position data is AHN = 255, AVN = 3, and the slope data is
The case where BN=-3 is shown. The second line LN2 is
A case is shown in which the left side of the screen is crossed, the cut point position data is AHN=0, AVN=6, and the slope data is BN=1. Note that a maximum of 32 lines can be displayed in one frame, but in the following operation explanation, two lines LN are used to simplify the explanation.
The case where 1 and LN2 are displayed will be explained.

(1) Operation during the vertical blanking signal period The data processor 13 provides the start address of the RAM 21a as a write address to the RAM 21a via the selector 22a, and also writes the boundary line data of the line LN1, that is, the cut point position data (255, 3) and slope data (-3)
is given to the RAM 21a. RAM21 depending on
Boundary line data (AHN=255, AVN=3, BN=-3) of line LN1 is written to the first address of a. Next, the data processor 13
The write address for writing line LN2 to address 2 is given to RAM 21a via selector 22a, and the boundary line data (AHN
=0, AVN=6, BN=1) is given to the RAM 21a. Accordingly, RAM21a has a line at address 2.
LN2 boundary line data (AHN=0, AVN=
6, BN=1) is written and stored.

(2) Operation during horizontal scanning period and horizontal blanking signal period Now, the vertical position of the electron beam is 0, that is, 1
Assuming that we start the main horizontal scan,
The horizontal address of the electron beam is given to the RAM 21a via the selector 22 as a read address. At this time, address areas in the RAM 21a storing each line are sequentially addressed in synchronization with the horizontal position of the electron beam during one horizontal scanning period, and the stored contents are read out. First of all, the boundary line data AVN, AHN,
BN is read and the corresponding register 2
3a, 23b, 23c and is loaded. At this time, since the vertical address is 0,
The comparator 25 determines that the vertical address (VA=0) is smaller than the vertical cut point position data (AVN=3), and sends the detection signal to the selector 22.
give to b. In response, the selector 22b selects the horizontal cut point position data (AHN=255) stored in the register 23b and supplies it to the RAM 21b as the intersection point position data. RAM21b
is stored as the intersection position data (HCN=255) of the line LN1 in synchronization with the write pulse given from the write control circuit 26a in the storage area specified by the horizontal address (HA=0 to 7) at that time.

Next, in the period when the horizontal address HA is 8 to 15, the line stored in the RAM 21a is
Boundary line data AVN, AHN, BN of LN2 are read out, and the corresponding registers 23a, 2
3b and 23c and loaded. In this case as well, the comparator 25 outputs the vertical address VA.
is smaller than the cut point position data AVN of the line LN2, and the detection signal is sent to the selector 22.
give to b. Accordingly, the selector 22b selects the data AHN (=
0) is given to the RAM 21b. The RAM 21b stores data AHN of the line LN2 as intersection position data (HCN=0) in a storage area corresponding to the horizontal address (HA=8 to 15). Such an operation is performed for each line stored in the RAM 21a during the horizontal scanning period of the vertical address (VA=0).

The above-described operation is performed during each horizontal scanning period for vertical addresses VA=1 and 2. In both cases, the comparator 25 derives a detection signal indicating that the vertical address is smaller than the data AVN, so the same operation as in the horizontal scanning period of the first horizontal scanning line is performed.

Note that when the vertical address VA is between 0 and 2, the data for displaying a line on the left or right edge of the screen is
Since the data is written to the RAM 21c, no lines are displayed on the scanning display 11.

And if the vertical address VA is 3, the line
At the timing when the boundary line data AVN, AHN, and BN of LN1 are read, the comparator 25 derives a coincidence output. Accordingly, the selector 22b selects the count value of the addition/subtraction counter 24. At this time, the addition/subtraction counter 24 receives the slope data BN (=-3) given from the register 23c and the register 23d.
The intersection position data HCN (=AHN=
255), and the added value (252) is given to the selector 22b. Therefore, the RAM 21b stores the intersection position data HCN (=252) of the intersection P11 where the next horizontal scanning line and the line LN1 intersect in the storage area corresponding to the line LN1. In the case of line LN2, the comparator 25 does not detect that the vertical address VA is larger than the data AVN, so the data AHN (=0) is used as the intersection position data HCN for the line.
It will be stored in the area of RAM 21b corresponding to LN2.

Then, in the next horizontal blanking signal period, the write address of the RAM 21c is specified based on the intersection position data HCN of the lines LN1 and LN2 written in the RAM 21b in the previous horizontal scanning period. Therefore, the RAM 21c stores the color code LC corresponding to the line LN1 read from the ROM 27 at that time in the area corresponding to the line LN1. In addition, RAM21 corresponding to line LN2
Data for displaying a line at the left or right end of the screen will be written in area c.

During this horizontal blanking signal period, the color generating circuit 27 provides a signal representing the black level (BL) to the scanning display 11.

Next, in the horizontal scanning period when the vertical address is VA=4, the intersection position data HCN (=249) of the intersection position P12 that intersects with the line LN1 in the horizontal scanning period when the vertical address is 5 is the line LN1 of the RAM 21b.
is written to the area corresponding to. At this time, the line
In the area of the RAM 21b corresponding to LN2, data AHN (=0) is written as intersection position data HCN in the same manner as in the above case.

At the same time, during the horizontal scanning period of vertical address VA (=4), selector 22c provides vertical address HA as a read address to RAM 21c. Therefore, RAM21c has horizontal address
At the timing of the address corresponding to the intersection position P1, HA gives the color code to be displayed at the intersection position P11 of the line LN1 to the register 23e and causes it to be loaded.
The color code to be displayed at the intersection point P11 of this line LN1 is converted into a color signal by the color generation circuit 27 and is applied to the scanning display 11. As a result, the line
Part of LN1 will be displayed.

Thereafter, in the same way, during the horizontal scanning period when the vertical address is VA=5, the comparator 25 selects the line LN.
It is detected that the vertical address VA is larger than the data AVN of 1, and the adder 2 is sent to the selector 22b.
Select output 4. For this reason, RAM21b
is the intersection position data of the new intersection position P13.
RAM21b where HCN (=246) corresponds to line LN1
is written in the area.

On the other hand, in the horizontal scanning period when the vertical address is VA=6, the comparator 25 is connected to the adder 24 at the timing when the boundary line data of line LN2 is read.
A signal for selecting is given to the selector 22b. By this, RAM2 corresponding to line LN2
In area 1b, there will be a line in the next horizontal scanning period.
Intersection position data HCN (=1) of intersection position P21 intersecting LN2 is written.

Thereafter, in the same way, based on the horizontal address HA where lines LN1 and LN2 intersect with the next horizontal scanning line, the horizontal address where the color code of that line should be displayed is determined.
It is stored in the area of RAM 21c corresponding to HA. Then, in the next horizontal scanning period, the color corresponding to the type of line is displayed on the scanning display 11 based on the color code stored in the RAM 21c.

In this way, the intersection position data between the line to be displayed and the horizontal scanning line is obtained based on the boundary line data supplied from the data processor 13, and this intersection position data is used as data to be written in the RAM 11c. , there is an advantage that the circuit configuration for specifying the write address of the RAM 21c can be easily and inexpensively manufactured. Also, because the outline of the model is displayed as a line rather than as a surface,
This has the advantage that the storage capacity of the RAM 21c can be significantly reduced and it can be manufactured at low cost.

By the way, when there are many lines to be displayed on the screen of the scanning display 11, the lines may be concentrated at one point on the screen. In such a case, if the model is to be displayed as a surface, a memory equivalent to the RAM 21c is required for each line. This is because when the contour lines of the model intersect, the intersection takes precedence over writing afterward, so the data of the previous line disappears, and the data of the contour line surrounded by the part that intersects with the previous line (i.e. (surface) disappears and becomes discontinuous.
As a result, surfaces of the model may be cut by unnecessary lines, or unnecessary lines may be added, resulting in surfaces that are not originally intended to be displayed. In order to prevent this, it is necessary to store position data for each contour line of the model so that it is not influenced by other lines. In this case, in this example
Memory corresponding to the RAM 21c is required for the number of lines displayed on the screen of the scanning display 11, which greatly increases the number of parts and makes it extremely expensive.

On the other hand, in this embodiment, lines are displayed without displaying surfaces, and in order to display the lines, the write address of the RAM 21c is specified by intersection position data calculated based on boundary line data. Therefore, even when displaying lines three-dimensionally, the circuit configuration is simple, and there is an advantage that the display can be controlled with a small number of parts without causing line breaks. As a result, according to this embodiment, lines that change three-dimensionally can be displayed with a simple configuration and at low cost, so that it can be applied to low-cost devices such as video game devices, and the content of video games can be improved. It can also be applied to things that require three-dimensional display.

As described above, the present invention has a somewhat inferior image representation ability, but the structure can be simplified and the cost can be reduced, so that it can be applied to video game machines that require lower prices. Also, since the data of the point that cuts the left side, top side, or right side of the screen is used as the starting point of the line, the starting point coordinates are not limited to the display screen of the screen, and it is possible to display a line that appears to extend from space outside the screen frame. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the principle of this invention. FIGS. 2A, 2B and 2C are diagrams schematically showing the display state of a scanning display for explaining the principle of this invention. . FIG. 3 is a specific circuit diagram of an embodiment of the present invention. Fourth
FIGS. 4A, 4B, and 4C are diagrams schematically showing the data flow for each vertical blanking signal period, horizontal scanning period, and horizontal blanking signal period to explain the operation of the present invention. FIG. 5 is a diagram schematically showing the display state of the scanning display 11 for explaining the operation of FIG. 3. In the figure, 11 is a scanning display; 12 is a scanning display;
12a is a viewpoint data generator, 12a is an operation unit, and 12b is a viewpoint data generator.
13 is a simulation computer; 13 is a data processor; 14 is a computer; 15 is a clock generator; 20 is an image generator;
21c is RAM, 22a to 22c are selectors, 2
3a to 23e are registers, 24 is an adder, 25 is a comparator, 26a and 26b are write control circuits, and 27 is a
ROM, 28 indicates a color generation circuit.

Claims (1)

[Scope of Claims] 1. A display control device for displaying three-dimensionally changing lines on the screen of a scanning display, which display should be displayed in one frame during the vertical blanking period of the scanning display. data generating means for generating, for each of a plurality of lines, coordinate data including cutting point data indicating the vertical or horizontal position of a point cutting the outline of the screen, and slope data for each line; a first storage means for storing cut point data and the slope data of each line to be displayed in a certain vertical unit; a vertical scanning address indicating the vertical position of the electron beam of the scanning display is a cut point of each line; a detection means for sequentially detecting that the data is larger than the vertical position; and in response to the output of the detection means, calculates based on the cutting point data of each line and the slope data during the horizontal scanning period of the scanning display. a calculation means that updates and sequentially obtains the intersection position data of each line to be displayed and the next horizontal scanning line; a second storage means that stores the intersection position data of each line obtained by the calculation means; a third storage means for temporarily storing identification data of each line to be displayed in the next horizontal scanning period of the scanning display; and a fourth storage means for pre-storing data identifying the type of line to be displayed at the intersection point. Means: writing means for writing the identification data stored in the fourth storage means into the third storage means using the intersection position data as a write address during the horizontal blanking period of the scanning display; , and a display drive means for displaying dots indicating each of the lines on the scanning display during a horizontal scanning period of the scanning display, based on identification data stored in the third storage means. Display control device with shaped display. 2. The scanning display includes means for generating a horizontal blanking signal, and the writing means writes the identification data stored in the fourth storage means to the third storage means during the period of the horizontal blanking signal. A display control device for a scanning display according to claim 1, wherein the information is written in a storage means. 3. The writing means reads the identification data stored in the fourth storage means in a time-division manner at predetermined time intervals obtained by dividing the horizontal blanking signal period by the number of lines, and writes the identification data to the third storage means. 3. A display control device for a scanning display according to claim 2, wherein the information is written in a storage means. 4. The scanning display is capable of color display, the fourth storage means stores a color code representing the color of the line to be displayed as the identification data, and the display driving means A display control device for a scanning display according to any one of claims 1 to 3, comprising color signal generating means for generating a color signal based on a color code.