JP3005389B2 - Polygon 3D display system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polygonal three-dimensional display system, and more particularly, to a polygonal three-dimensional display system for displaying a polygonal column in a three-dimensional manner in a graph display function of an information processing apparatus.

[0002]

2. Description of the Related Art In an application program for displaying a graph, a three-dimensional graph is often used as one of means for visually displaying data or a graphic itself. As a three-dimensional image element used in a three-dimensional graph, a three-dimensional image obtained by projecting a polygonal column with parallel rays from obliquely above is the most common.

Conventionally, in order to realize this kind of function,
The coordinate values are controlled as three-dimensional coordinate values inside the program, and complicated coordinate conversion processing (processing of converting data into polar coordinates and calculating display coordinates) and hidden line control processing (behind the scenes, the shadows cannot be seen. (Drawing line erasure processing) has been generally performed.

[0004]

The above-mentioned conventional processing method requires a coordinate conversion process for display data and a hidden line control process at the time of drawing, so that the program is more specialized than other planar graphs. Easy to be complicated. As a result, there are disadvantages in that the execution program is enlarged, the calculation / display processing is slowed down, and the maintenance becomes difficult.

An object of the present invention is to provide a polygonal three-dimensional display system capable of performing high-speed three-dimensional display of a polygon with a small-scale program of only two-dimensional processing without performing complicated coordinate conversion processing and hidden line control processing. It is in.

[0006]

According to the present invention, there is provided a polygonal three-dimensional display system in which coordinate values corresponding to respective vertices of a bottom surface of a polygonal column to be displayed as a three-dimensional image are stored in a clockwise or counterclockwise arrangement direction. obtaining a rectangular coordinate value storage area, the stereoscopic image height storage area stereoscopic image height data is stored relating to the height of the polygonal pillar, a write-area reading sequentially the coordinates from the polygon coordinate value storage area Data stored by
After determining the storage order, increase the X-axis of the side of the polygonal pillar.
Sides are classified into sides to be drawn and sides not to be drawn from the decrement.
A drawing information control unit that determines a drawing order based on the Y-axis component values of the above, and the drawing information control unit that determines the drawing order based on the coordinate values of the polygon coordinate value storage area and the three-dimensional image height data of the three-dimensional image height storage area. A side drawing unit that creates display information for drawing the three-dimensional image side surface in accordance with the drawn drawing order and outputs the information in an overlaid display format to an image memory; the coordinate values of the polygon coordinate value storage area and the three-dimensional image height storage area And a top surface drawing unit for creating display information for drawing the top surface of the three-dimensional image based on the three-dimensional image height data, and outputting the information to the image memory in a superimposed display format.

[0007]

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

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention.

As shown in FIG. 1, a polygonal three-dimensional display system according to this embodiment has a polygon in which coordinate values of respective vertices of a bottom surface of a polygonal column to be displayed as a three-dimensional image are stored in a clockwise or counterclockwise direction. A coordinate value storage area 2 and a three-dimensional image height storage area 3 in which three-dimensional image height data representing the height of a polygonal column is stored.
A display information control device 1 for creating display information as a three-dimensional image of a polygonal column only by two-dimensional control from data in the polygon coordinate value storage area 2 and the three-dimensional image height storage area 3, and an output device 4. Have been.

The display information control device 1 reads the coordinate values of the bottom face from the polygon coordinate value storage area 2 in order and identifies the arrangement direction, and then classifies the polygon pillar into a side in which the side is drawn and a side in which the side is not drawn. A drawing information control unit 11 for determining a drawing order, and display information for drawing each stereoscopic image side surface from the coordinate values of the bottom surface and the stereoscopic image height data are created in accordance with the drawing order determined by the drawing information control unit 11. A side drawing unit 12 that sequentially writes in an image memory in an overlaid display format, and display information for drawing a top surface of a 3D image from coordinate values of the bottom surface and 3D image height data, and outputs the image to the image memory in an overlaid display format. And a top surface drawing unit 13.

FIG. 2 shows the display information control device 1 shown in FIG.
2 is divided into drawing information control processing performed by the drawing information control unit 11, side drawing processing performed by the side drawing unit 12, and top drawing processing performed by the top drawing unit 13. Hereinafter, each process will be described in detail with reference to FIGS.

The drawing information control unit 11 of the display information control device 1
First, the coordinate values of each vertex are read from the polygon coordinate value storage area 2 in the order of storage (step S1), and the control information relating to the side drawing of the stereoscopic image includes the coordinate value array direction, the drawing side determination array, and the drawing order control array. Various information is created sequentially (steps S2 to S4).

The polygon coordinate value storage area 2 stores coordinate values A _i (x, y) of n vertices forming the bottom surface of a polygonal column to be rendered as a three-dimensional image as a coordinate value array. I have. The stored coordinate values may be stored clockwise or counterclockwise with respect to the polygon, but must be stored in a continuous order.

FIG. 3 is an explanatory diagram for explaining a method of judging the arrangement direction of the coordinate value array performed first in step S2 after reading the coordinate value array in step S1.
Although an arbitrary polygon can be designated in the present invention, FIG. 3 shows a case of a polygon composed of four points as a specific example.

In the polygon coordinate value storage area 2, FIG.
Coordinate values of four vertices of the vertex _A 1 to A ₄ shown in (a) is 3
It is assumed that the coordinates are stored as a counterclockwise coordinate value array as shown in FIG. The drawing information control unit 11 is configured as shown in FIG.
Are read in the order of index values, and the read values are substituted into the right side of the discriminant shown in FIG.
Ask for. The discriminant equation of FIG.
_{For i} (x, y), the coordinate value A of the next coordinate value array
_{i + 1} (x, y) and projection points B _i , B on the respective y axes
_This is an equation in which the area of a trapezoid composed of four points, _{i + 1} , is obtained and added for a variable i. Here, A _i (x, y)
And the line connecting A _{i + 1} (x, y) is one side of a polygon,
In other words, the area of the trapezoid for all sides is added. The sign of the area S thus determined is determined according to the determination rule of FIG. 3D, and the arrangement direction of the coordinate value array is identified.

In the case of the coordinate value array shown in FIG. 3B, sides (A ₁ , A ₂ ), sides (A ₂ , A ₃ ), and sides (A ₄ , A ₁ )
Is added to the sum of the trapezoids of the positive areas each having one side (shaded area) and the trapezoid whose area is one side of the side (A ₃ , A ₄ ) as a result, the squares (A ₁ , A ₂ , A ₃ , A ₄ ) has a negative area S, and is thus identified as counterclockwise by the determination rule of FIG.

Conversely, when the coordinate values are stored clockwise, the sides (A ₁ , A ₄ ), the sides (A ₃ , A ₂ ), and the sides (A ₂ , A ₂ ,
All trapezoids each having A ₁ ) as a side have a negative area, and as a result of adding a positive trapezoid having an area having a side (A ₄ , A ₃ ) as a side, a square (A ₁ , A ₂ , A ₃ , A) is obtained. ₄ ) Since the area S is positive, it is identified as clockwise by the determination rule. After setting a flag indicating the coordinate value array direction based on the identification result, the process proceeds to step S3 to determine the drawing side of the next three-dimensional image.

In the drawing side determination in step S3,
The drawing information control unit 11 sequentially compares the x-axis components of the coordinate value array position (index) and the next coordinate value array position (index) from the top of the previously read coordinate value array to increase or decrease. Find out. As shown in FIG. 4, when a polygonal column (z> 0) having a polygon (hexagon) on the xy plane as a bottom surface is stereoscopically displayed (projection from the direction of y <0, z> 0), If the coordinate values of the vertices of the rectangular base are placed counterclockwise in the coordinate value array, the side where the x-axis component increases, and conversely if it is placed clockwise, the side where the x-axis component decreases,
These are one side of the bottom surface that constitutes the (visible) stereoscopic image side surface that must be drawn (marked with a circle in FIG. 4 and indicated by a solid line). Conversely, the side indicated by a dashed line in FIG. 4 and marked with x (the side where the x-axis component decreases when counterclockwise, the x
The side with the increased axis component) is one side of the bottom surface constituting the side of the three-dimensional image that does not need to be drawn (not visible). If the x-axis components are equal, the two points are changed only in the y-axis component and are not displayed as a surface but are lines. Therefore, it may be determined that the side of the three-dimensional image including this side is not drawn (the drawing may be performed, but the number of drawing processes increases accordingly).

According to this determination method, drawing determination is performed for all sides of the polygon with reference to the flag indicating the coordinate value array direction previously obtained in step S2, and the flag "1" is set when the determination result is drawn. Flag "0" when not drawing
As shown in FIG. 5, the image data is stored in a location corresponding to the coordinate value array of the drawing side surface determination array. That is, the determination result of the side starting from the point of the index m in the coordinate value array is stored in the position of the index m in the drawing side surface determination array. By making this drawing determination, it is possible to draw only the side that is actually visible, instead of drawing all the sides of the stereoscopic image. Therefore, it is possible to reduce the weighted side surface drawing processing in the processing of the entire system and increase the processing speed of the system.

Next, the drawing information control section 11 executes step S
In step 4, a drawing order control array is created as control information on the drawing order on the side of the stereoscopic image in order to display a stereoscopic image without being conscious of hidden line control processing. First, the previously read index values of the coordinate value array are sequentially stored in the drawing order control array, and then the index sorting of the drawing order control array is performed in descending order using the y-axis component of the coordinate value array as a key.
In the drawing order control array after sorting, as shown in FIG.
The index values of the coordinate value array and the drawing side surface determination array are stored as array values in the order of drawing. From the sorted order, that is, from the largest y-axis component of the coordinate value of the starting point of each side constituting the polygon of the bottom surface, display information of the three-dimensional image side including the side is created and sequentially stored in the image memory. By superimposing and displaying, it is possible to complete a stereoscopic projection image without performing hidden line control processing.

The drawing side determination array and the drawing order control array created by the drawing information control unit 11 are passed to the side drawing unit 12 together with the coordinate value array read from the polygon coordinate value storage area 2, where the three-dimensional image side The display information necessary for drawing is created.

FIG. 6 is an explanatory diagram of the side surface drawing process (steps S5 to S7) performed by the side surface drawing unit 12.

The side surface drawing unit 12 first reads solid image height data representing the height of a polygonal column displayed as a solid image from the solid image height storage area 3 (step S5). Next, from the top of the drawing order control array created by the drawing information control unit 11, the corresponding index value of the drawing side determination array is referred to by the stored index value. If the index value stored at the jth position in the drawing order control array is m, the mth position in the drawing side determination array is referred to, and the flag of the drawing side determination result stored in the mth array is set to “ If "0", the side is not drawn, and the processing moves to the (j + 1) th position in the drawing order control array. If the flag of the drawing side determination result is “1”, the side, that is, the three-dimensional image side including the m-th side of the polygon is drawn.

Here, the side surface of the polygonal column to be drawn is composed of four points: the m-th coordinate value in the coordinate value array, the (m + 1) -th coordinate value, and coordinate values having different heights (z components). But obliquely above the xy plane at an angle θ (y <0, z>
When projected from 0), the y-axis component of the bottom surface becomes sin θ times,
Since the height is projected by cosθ times, the display coordinate values of the stereoscopic image side surface are calculated from the y-axis component of the coordinate values in the coordinate value array and the stereoscopic image height data, and the stereoscopic image side surface is calculated based on these values. The display information of each point in is created (step S6). That is, when displaying only the outline of a surface as a three-dimensional image, if the display information of each pixel corresponding to the outline is, for example, “1” in binary display of black and white, each point in the surface surrounded by the outline , Display information of “0” is created. Next, in step 7, the display information is written in the image memory in an overlaid display format,
The process moves to the next aspect and the same process is repeated.

As described above, the drawing order stored in the drawing order control array is a drawing order in which the y-axis component of the coordinate value of the starting point of each side constituting the polygon is large, that is, from the rear side surface. When the front side is drawn, the display information of the part that is not visible because of the overlap of the rear side is erased, so that the hidden line control processing becomes unnecessary.

When the display information has been output to the image memory in superimposed display for all of the three-dimensional image side surfaces in the order of the drawing order control, the information of the display coordinate values obtained from the coordinate value array and the three-dimensional image height data is displayed on the top surface. The processing is passed to the section 13 where the top surface drawing processing of the stereoscopic image is performed (steps S8 and S9).

In the top surface drawing unit 13, the display coordinate values of the polygon on the bottom surface are shifted in the y-axis direction by the display height of the stereoscopic image, and the coordinate values for display of the polygon on the top surface of the stereoscopic image are obtained. And display information of the top surface of the three-dimensional image is created from these (step S
8) Output to the image memory in a superimposed display format (step 9).

The display information in the image memory created by the display information control device 1 as described above is passed to the output device 4 and displayed as a stereoscopic image on a display or output on paper.
As an example of the result output to the printing apparatus in FIG. 7, an example of a three-dimensional image in which the topographic map of Hokkaido is approximated by a polygon, the top surface is displayed as a contour line, and the side surface is embossed with a colored display (mottle pattern in the figure). Is shown.

As described above, by performing both the side surface drawing process and the top surface drawing process of the three-dimensional image by overlapping display,
Display coordinate values are calculated only by two-dimensional control of polygon coordinate value data and stereoscopic image height data, and pseudo three-dimensional display of polygons is realized without performing hidden line control processing.

In the description of the above embodiment, the plane coordinate values of the bottom surface of the polygonal column are stored in the polygonal coordinate value storage area.
It has been described that the height of the polygonal column is stored in the three-dimensional image height storage area, and the display coordinate values for displaying as a three-dimensional image in the side surface drawing unit are calculated. If the area stores the projection coordinates of the bottom surface and the stereoscopic image height storage area stores the display height as a stereoscopic image,
There is no need to calculate it. Even in this case, the procedure of the coordinate array direction determination, the rendering side determination, and the rendering order determination performed by the rendering information control unit does not require any change, and the same procedure is performed using the coordinate values read from the polygon coordinate value storage area. Processing may be performed.

[0031]

As described above, the polygonal three-dimensional display system of the present invention performs only two-dimensional control of arbitrary polygon coordinate value data and three-dimensional image height data, and keeps the three-dimensional image side surface and the top surface constant. Since polygons are displayed three-dimensionally by drawing in overlapping order in the order, there is no need for complicated coordinate conversion processing and hidden line control processing associated with three-dimensional control for obtaining display coordinate values,
As compared with the conventional method, there is an effect that the program can be reduced in size, maintenance can be facilitated, and the display processing can be speeded up.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a flow of a process according to the embodiment.

FIG. 3 is an explanatory diagram of a determination process of a coordinate value array direction in the embodiment.

FIG. 4 is an explanatory diagram of a drawing side surface determination method according to the present embodiment.

FIG. 5 is an explanatory diagram of a creation process of a drawing side surface determination array in the embodiment.

FIG. 6 is an explanatory diagram of a side surface drawing process in the embodiment.

FIG. 7 is an explanatory diagram illustrating an example of an output result in the present embodiment.

[Explanation of symbols]

 Reference Signs List 1 display information control device 2 polygon coordinate value storage area 3 stereoscopic image height storage area 4 output device 11 drawing information control unit 12 side drawing unit 13 top drawing unit

Claims (1)

(57) [Claims] 1. A polygon coordinate value storage area in which coordinate values corresponding to respective vertices of a bottom surface of a polygonal column displayed as a three-dimensional image are stored in a clockwise or counterclockwise arrangement direction, and a height of the polygonal column. Day stereoscopic image height data is stored by obtaining a stereoscopic image height storage area stored, the write-area read from said polygon coordinate value storage area coordinate values sequentially related
X-axis of the side of the polygonal column after judging the storage order of data
Sides that are classified into sides to be drawn and sides not to be drawn from the increase / decrease value
A drawing information control unit that determines a drawing order based on a Y-axis component value of a surface; and a drawing information control unit based on coordinate values of the polygon coordinate value storage area and stereoscopic image height data of the stereoscopic image height storage area. A side surface drawing unit that creates display information for drawing the three-dimensional image side surface in accordance with the determined drawing order and outputs the information in an overlaid display format to an image memory; and stores the coordinate values of the polygon coordinate value storage area and the three-dimensional image height. And a top surface drawing unit for creating display information for drawing the top surface of the three-dimensional image based on the three-dimensional image height data of the area and outputting the information to the image memory in a superimposed display format. 3D display system.