JPH0394389A - Method for displaying three-dimensional graphic rotation and graphic processor - Google Patents

Abstract

PURPOSE:To prevent a three-dimensional graphic from projecting to the outside of a display screen at the time of rotating the graphic on the screen by finding out a solid including the displayed graphic and setting up an axis intersecting with the approximate center of the solid as the axis of rotation. CONSTITUTION:The graphic processor is constituted of an image display device (display) 8, a CPU 9, a memory 10, a graphic memory 11, a connection register 12, a graphic processor 13, a frame memory 14, and input devices 15 to 18. The solid including the graphic to be rotated on the screen of the device 8 is found out and a straight line passing the approximate center of the solid is set up as the axis of rotation of the graphic. Consequently, the graphic can be prevented from projecting from the display screen during its rotation or after the rotation, so that the backing of the graphic processing can be prevented and the processing can be efficiently executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for displaying a three-dimensional image on an image display device, and particularly to a three-dimensional figure rotation display method and apparatus for rotating the three-dimensional image on a screen. Regarding.

[Conventional technology]

A method for displaying three-dimensional figures will be explained with reference to FIG.

A three-dimensional figure is defined by a figure definition coordinate system 6. A rotational transformation is applied to the figure defined in the figure definition coordinate system 6, and the figure is transformed into a figure in the projected coordinate system 1. Note that the origin and the X, Y, and Z axes of the projected coordinate system 1 are the same as the origin and the X, yTZ axes of the figure definition coordinate system 6. Among the figures in this projected coordinate system 1, those to be displayed are:
Only the figures included in the display target space 5 are displayed. The figure in the display target space 5 is projected onto the display target space back surface 7, and its projected view is displayed. The rotational display of a three-dimensional figure is performed by changing the rotational transformation for converting the figure from the figure definition coordinate system 6 to the projected coordinate system 1.

Note that the position and size of the display target space 5 in the projected coordinate system 1 are fixed regardless of the rotational transformation described above.

In conventional three-dimensional figure processing, the U-axis and V axis, which are fixed to the figure definition coordinate system 6, are used as rotation axes for rotational transformation.
Axis and W axis 2 are used. Note that related devices of this type include, for example, Japanese Patent Application Laid-Open No. 62-67682.
There are those described in Japanese Patent Application Laid-Open No. 62-25427.

[Problem to be solved by the invention]

The above conventional technology does not take into account the positional relationship between the rotation axis used for rotation conversion and the figure to be rotated.
As shown in the figure, if the rotation axis 2 and the figure to be rotated are far apart, the figure may move out of the display target 5 due to rotation and may no longer be displayed. Therefore, when rotating a figure on the display screen using an interactive operation, it was necessary to redo the operation, resulting in poor operability. An object of the present invention is to provide means for determining a rotation axis in which a three-dimensional figure is rotated on a display screen so that the figure does not protrude outside the screen.

[Means to solve the problem]

The above problem is solved in a three-dimensional figure rotation display method that interactively rotates a three-dimensional figure displayed on an image display device.
This is achieved by including a procedure for finding a solid that includes the figure being displayed, and a procedure for setting an axis that intersects near the center of the solid as a rotation axis.

The above problem can also be solved by the three-dimensional figure rotation display method according to claim 1, wherein the solid is a rectangular parallelepiped circumscribing the figure to be rotated, and an axis passing near the center of the rectangular parallelepiped is set as the rotation axis. The solid is a rectangular parallelepiped that includes all the figures being displayed on the image display device, each surface of the rectangular parallelepiped is circumscribed by at least one figure, and the axis passing near the center of the rectangular parallelepiped is set as the rotation axis. The present invention is also achieved by the three-dimensional figure rotation display method according to claim 1 or 2.

The above object is also achieved by the three-dimensional figure rotation display method according to claim 1 or 2, wherein the solid is a rectangular parallelepiped that encompasses the entire three-dimensional figure display space of the image display device.

The above problem is also solved by the three-dimensional figure rotation display method according to any one of claims 2 to 4, wherein the plane defining the shape of the rectangular parallelepiped is parallel to a plane containing any two axes of the device coordinate system of the image display device. This can also be achieved by The above-mentioned problem can also be achieved by a computer-aided graphic creation method comprising a three-dimensional graphic rotation display method according to any one of claims 1 to 5.

The above-mentioned problem also requires an image display device capable of displaying a three-dimensional figure, an input device that interactively instructs the amount of rotation of the three-dimensional figure around a predetermined rotation axis, and an input device based on the input instruction. a control calculation device that performs calculations on the three-dimensional figure and displays the three-dimensional figure by rotating it around the rotation axis, wherein the control calculation device is connected to an input device via a common line. a CPU connected to the CPU, a memory connected to the CPU and storing input data and a program for operating the CPU, a figure memory connected to the common line and storing figure types, coordinate data, and figure identifiers for each figure; a communication register connected to the common line and storing the command type, rotation matrix specified value, display target space specified value, screen coordinate specified value, figure identifier response value, existence space response value; a graphics processor whose end is connected to the image display device;
The graphics processor calculates coordinate values of a solid that circumscribes a figure specified by the input device,
The CPU is also operated by a graphic processing device which sets a straight line passing through the coordinates near the center of the solid as the rotation axis of the specified graphic.

The above-mentioned problem is also solved in a computer-aided figure creation device comprising a figure processing device capable of processing three-dimensional figures and an input device that interactively performs input to the figure processing device, wherein the figure processing device is The invention can also be achieved by a computer-aided graphic creation device, which is a graphic processing device described in .

[Effect]

According to the present invention, a figure to be rotated (a figure to be rotated)
First, a solid containing is found. This figure to be rotated is displayed on the display screen, and the coordinates of the solid that includes this figure are also included in the display screen. Since the rotation axis of the figure to be rotated is set to pass near the center of the solid, when the figure to be rotated is rotated, the figure rotates within the area of the solid. Since each coordinate of the three-dimensional object is within the display screen, the rotation target figure during and after rotation is also within the display screen, and the figure does not escape outside the display screen.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 8. FIG. 4 shows the main structure of a graphic processing device to which the present invention is applied. The CPU 9 includes an input processor 15 that reports data input from an input device to the CPU 9, a communication register 12, and a graphic memory l1. and the graphic memory 1 according to instructions from the CPU 9 written in the communication register l2.
A graphics processor 13 that interprets and processes graphic drawing commands registered in the computer 1 and a memory 10 are connected. A display 8 for displaying three-dimensional figures and command menus is connected to the graphic processor 3 via a frame memory 14.

The display 8 includes a display screen of 1280×1024 pixels.

The input processor 15 includes a mouse 16 and a keyboard 17, which are used to input commands such as rotation axis calculation method instructions, input coordinates on the display 8, etc., and a keyboard 17, which is used to input the amount of rotation when rotating and displaying a figure. The dial 18 is connected. The memory 10 includes an input processor 15
Analyzes the input data passed from , generates a graphic drawing command and registers it in the graphic memory l1, or writes various processing commands to the graphic processor 13 to the communication register ↓2, etc. The program to be executed and the data used when executing this program are stored. This data also includes the current display target space.

The processing performed by the graphics processor 13 also includes an operation of interpreting a graphic drawing command, developing it into pixel data, and writing it into the frame memory 14. As described above, the CPU 9 operates according to the programs stored in the memory 10.

The figure drawing command stored in the figure memory 1l is the fifth
As shown in figure A, it has a figure type 20 indicating the type of figure such as a straight line or a sphere, and coordinate data 21 corresponding to the figure type 20, and represents each figure in the figure definition coordinate system 6. Further, in order to identify the figure in the figure memory 11, a figure identifier 19 is added to the figure drawing command. Note that it is also possible to assign the same identifier to a plurality of figures.

As shown in FIG. 5B, the communication register 12 includes a command type 22, a rotation matrix designation value 23, a display target space designation value 24, a screen coordinate designation value 25, and a figure identifier response value 2.
6. It has a column for storing existential space response values 27 and the like. The command type 22 is a column in which the CPU 9 writes a command to the graphic processor 3, and either a "draw" command or a "search" command is written here. Directive type 22
When "drawing" is written in , the rotation matrix designation value 23 and the display target space designation value 24 are also written by the CPU 9 . The rotation matrix designation value 23 is a transformation matrix for rotational transformation from the figure definition coordinate system 6 to the projection coordinate system l, and the display target space designation value 24 is the transformation matrix for the rotation transformation from the figure definition coordinate system 6 to the projection coordinate system l.
The minimum and maximum values of the x, y, and z coordinates of the display target space 5 at . If the command type 22 is "Search" for selecting an image (figure) to be rotated on the screen, C
The PU 9 writes a rotation matrix designation value 23, a display target space designation value 24, and a screen coordinate designation value 25. The screen coordinate designation value 25 specifies the coordinate value of the location when the cursor being moved on the display screen is fixed on the figure to be rotated. At this time, as a response, the graphic processor 13 sets the figure identifier of the figure specified as a result of the search as the figure identifier response value 26, and sets the minimum and maximum values of the x, y, and z coordinates of the figure in the existential space as the existential space response. Write each value to 27. In this example, the existence space of the specified figure is the interior of a rectangular parallelepiped that is circumscribed by the figure specified as a result of the search and parallel to any of the XY plane, XZ plane, and YZ plane in the projected coordinate system. and is calculated for each shape identifier.

FIG. 3 shows an example of a processing procedure when rotating and displaying a three-dimensional figure using the figure processing apparatus having the above configuration.

Next, the processing procedure of the graphic processor 13 will be explained with reference to FIG. First, when "drawing" is written in the command type 22 in process 601, the graphic processor 13 displays the figure in the figure memory 11 on the display 8 according to the procedure shown in the figure. Graphics processor 1
3, first, in process 602, a graphic drawing command is read out from the graphic memory 11 and analyzed. Next, in process 603,
The rotation matrix designation value 23 of the communication register 12 is read out, and the figure in the projected coordinate system 1 is transformed into rotation using the read rotation matrix designation value. Next, in process 604, the display target space designation value 24 of the communication register 12 is read, and the portion outside the display target space 5 is removed based on the value of the read display target space designation value 24. Next, in process 605, the figure in the display target space 5 is projected onto the display target space back surface 7. Next, process 60
In step 6, the figure obtained by the projection is enlarged or reduced;
It is converted into a screen coordinate system (hereinafter referred to as device coordinate system) of the display 8 consisting of 1280×1024 pixels. In process 607, the figure converted to the device coordinate system is written into the frame memory 14. The above processing 602~
Step 607 is performed for all graphic drawing commands in the graphic memory 11, and the graphics registered in the graphic memory 11 are written into the frame memory 14↓. Frame memo IJ
When writing to the frame memory 14 is completed, the frame memory 14
The graphic written in is displayed on the display 8. Processes 601 to 608 correspond to step 301 in FIG.

When 'search' is specified (written) in the command type 22 in process 601, the graphic processor 13 searches the figure identifier of the figure containing the screen coordinates specified by the cursor on the display screen of the display 8 and its existence. space as the 6th
The information is reported to the CPU 9 according to the processing procedure shown in the figure. In the figure, processes 609 and 610 are the same as the above-mentioned processes 602 and 603, respectively, and processes 612 to 614 are the same as the above processes 604 to 606, so a description thereof will be omitted.

In process 611, the existence space of a group of figures having the same figure identifier as the figure identifier currently being processed is calculated. In process 615, it is determined whether the screen coordinate group constituting the figure currently being processed includes the coordinates written in the screen coordinate designation value 25 of communication register ↓2, and if so, process 6
At step 17, the graphic identifier of the graphic is written into the graphic identifier response value 26 of the communication register 12, and the existence space of the graphic is written into the existence space response value of the communication register 12, respectively.

On the other hand, if the screen coordinate group that constitutes the figure currently being processed does not include the screen coordinates written in the screen coordinate designation value 25 in the communication register 12, the process moves to step 616, and if the figure drawing command has not been read yet. It is checked whether there are any items, and if there are any items that have not been read yet, then processes 609 to 615 are repeated. Processing 609-6
17 corresponds to steps 302 and 303 in FIG.

Next, an outline of the processing performed by the CPU 9 for rotating a figure displayed on the display 8 will be explained with reference to FIG. 7A.

First, in process 701, a rotation axis is determined. keyboard 1
7 or when an instruction to recalculate the rotation axis is given via the mouse 6, the CPU calculates and sets the rotation axis. If recalculation of the rotation axis is not instructed, the rotation axis used in the previous rotation is reused.

Process 701 corresponds to steps 304 and 305 in FIG.

Next, in process 702, the amount of rotation is inputted using the dial 18 and taken into the CPU 9. In process 703, process 7
A rotation difference matrix, which will be described later, is calculated from the rotation axis determined in step 01 and the amount of rotation taken in step 702. Next, in process 7O4, the current rotation matrix, which is the current value of the rotation matrix used for rotational transformation of the figure from the figure definition coordinate system 6 to the projected coordinate system ↓, is multiplied by the rotation difference matrix to calculate a new current rotation matrix. Ru. Current rotator [Mcnew]
: [M. +1 [Mcotdl ・---・
・It is determined by (3). For example, if the origin of the rotation axis 2 is (p+q+r) of the figure definition coordinate system 6, and the U-axis, ##, and W-axis are parallel to the x, y, and z axes, then there is a distance of θU around the U-axis. The rotation difference matrix for new rotation is the point (x+y+z) on the figure definition coordinate system 6.
is converted to a point (X, Y.Z) on the projected coordinate system 1 by the following formula.

It is expressed as . Similarly, the rotation difference matrices when newly rotated by θV around the V axis and when newly rotated by θW around the W axis are is a transformation matrix representing the rotations. Rotating difference matrix [M. +], the old current rotation matrix is [Mco*a] + the new current rotation matrix is [MCIlewco, then [Mcne
wl is expressed as follows.

In process 705, the current rotation matrix calculated in process 704 is written to the rotation matrix specified value 23 of the communication register 12, and furthermore, "drawing" is written in the command type 22.
is set, the graphics processor 13 is activated, and the figures on the display 8 are rotated and displayed. Process 702 corresponds to step 306 in FIG. 3, and processes 703 to 705 correspond to steps 307 and 308.

Next, the determination of the rotation axis performed in process 701 of FIG. 7A will be explained with reference to FIG. 8. In process 801, screen coordinates are first input via the mouse 16. Processing 80
3, the input screen coordinates are written to the screen coordinate designated value 25 of the communication register l2, and the current rotation matrix stored in the memory 10 is written to the rotation matrix designated value 23 and stored in the memory 10. The current display target space is display target space rg! J specified value 24
, "search" is set in the command type 22, and the graphic processor 13 is started. The activated graphics processor 13 sets the existence space of the figure including the designated screen coordinates in the existence space response value 27 of the communication register 12.

In process 804, the existence space newly obtained in the process 803 is added to the existence space obtained in the previous search process (hereinafter referred to as the existence space integrated value). In this process, i) If the newly obtained existential space is completely included in the existential space integrated value, the existential space integrated value is not changed.

5) In cases other than i), the existence space integrated value is expanded to include the newly obtained existence space. However, like the existence space, the existence space integrated value is a rectangular parallelepiped made of planes parallel to the plane containing any two coordinate axes of the projected coordinate system.

In process 805, the center coordinates of the finally determined existential space integrated value are determined, and the origins of the U-axis, V-axis, and W-axis of the rotation axis 2 are set at this center coordinate position. Also, the u, v
, w axes are set parallel to the coordinate axes x, y, and z of the projected coordinate system, respectively.

In the above process, as shown in FIG. 1A, the specified figure (
In the figure, the center coordinates of the existence space 3 of the sphere (sphere) are set as the origin of the rotation axis, but as shown in Figure 1B, the existence space 4 circumscribing all the figures in the display target space 5 is calculated, and the The center coordinates of the existence space 4 may be set to the origin of the rotation axis.

Furthermore, as shown in FIG. IC, the center coordinates of the display target space (display screen) 5 may be calculated, and this center coordinate position may be set as the origin of the rotation axis 2.

In addition, in the above embodiment, a rectangular parallelepiped is selected as the space in which the figure exists, but instead of a rectangular parallelepiped, a point-symmetric object such as a sphere or a cylinder that encompasses all the displayed figures or specified figures or the display screen is selected. A polyhedron may be assumed, and an axis passing through the center or near the center of the assumed sphere or polyhedron may be set as the rotation axis.

Further, in the above embodiment, the rotation axes u, v, and w are set parallel to the coordinate axes x, y, and z of the projected coordinate system, respectively, but they do not necessarily have to be parallel.

In the above embodiment, the rotation amount is set by manual operation of the dial 18, but as shown in FIG. 7B, the rotation of the figure can be adjusted by starting the process 703 again after the process 705 is completed. It may be performed continuously.

According to this embodiment, since the figure displayed on the display 8 is rotated without causing the figure to deviate from the display screen, it is possible to observe all rotational states on the display screen. By applying this to a generation support device, it is possible to process graphics efficiently and in a consistent manner.

〔Effect of the invention〕

According to the present invention, a solid that includes a figure to be rotated on the screen of an image display device is obtained, and a straight line passing near the center of the solid is set as the rotation axis of the figure. It is possible to prevent the image from escaping from the display screen and not being displayed on the screen during or after the rotation, which has the effect of eliminating the need to go back after graphic processing and making the processing more efficient.

[Brief explanation of drawings]

Figures IA, IB, and IC are perspective views showing a method for determining a rotation axis, Figure 2 is a perspective view showing an overview of rotational display of a three-dimensional figure, and Figure 3 is a procedure showing an embodiment of the present invention. 4 is a block diagram showing the main structure of an embodiment of the present invention, FIG. 5A is a plan view showing an example of graphic drawing commands stored in the graphic memory, and FIG. 5B is a block diagram showing an example of graphic drawing commands stored in the communication register. A plan view showing an example of data, FIG. 6 is a procedure diagram showing an example of processing contents of the graphic processor, FIGS. 7A and 7B are procedure diagrams showing an example of figure rotation operation, and FIG. 8 is a procedure for determining the rotation axis. FIG. 9 is a perspective view showing the problems of the prior art. 2... Rotation axis, 3, 4... Solid (existence space), 5.
...Three-dimensional figure display space, 8...Image display device (display), 9...CP
U, 10...Memory, 11...Graphic memory, l2.
...Communication register, 13...Graphic processor, 15, 16, 17, 18...Input device.

Claims (1)

[Scope of Claims] 1. In a three-dimensional figure rotation display method for interactively rotating a three-dimensional figure displayed on an image display device, a procedure for obtaining a solid body that includes the figure being displayed, and a method for determining the vicinity of the center of the solid body. A method for rotating a three-dimensional figure, comprising: setting an axis that intersects with the rotation axis as a rotation axis. 2. Three-dimensional figure rotation according to claim 1, wherein the solid is a rectangular parallelepiped circumscribing the figure to be rotated, and an axis passing near the center of the rectangular parallelepiped is set as the rotation axis. Display method. 3. The solid is a rectangular parallelepiped that includes all the figures being displayed on the image display device, each surface of the rectangular parallelepiped is circumscribed by at least one figure, and the axis passing near the center of the rectangular parallelepiped is the rotation axis. 3. The three-dimensional figure rotation display method according to claim 1, wherein the three-dimensional figure rotation display method is set to . 4. The three-dimensional figure rotation display method according to claim 1 or 2, wherein the solid is a rectangular parallelepiped that encompasses the entire three-dimensional figure display space of the image display device. 5. The three-dimensional figure rotation display method according to claim 2, wherein the plane forming the rectangular parallelepiped is parallel to a plane containing any two axes of a device coordinate system of the image display device. . 6. A computer-aided graphic creation method comprising the three-dimensional graphic rotation display method according to any one of claims 1 to 5. 7. An image display device capable of displaying a three-dimensional figure, an input device for interactively instructing the amount of rotation of the three-dimensional figure around a predetermined rotation axis, and performing calculations based on the input instructions. , a control calculation device that rotates and displays the three-dimensional figure around the rotation axis, a CPU in which the control calculation device is connected to an input device via a common line; a memory connected to the CPU and storing input data and a program for operating the CPU; a figure memory connected to the common line and storing figure types, coordinate data, and figure identifiers for each figure; and a figure memory connected to the common line. command type, rotation matrix specified value, display target space specified value, screen coordinate specified value, figure identifier response value,
a communication register for storing an existence space response value; and a graphics processor connected at one end to the common line and at the other end to the image display device, and the graphics processor is connected to the input device. The CPU calculates the coordinate values of a solid that circumscribes the specified figure, and the CPU sets a straight line passing through the coordinates near the center of the solid as the rotation axis of the specified figure. A graphic processing device characterized by. 8. A computer-aided figure creation device comprising a figure processing device capable of processing three-dimensional figures and an input device that interactively performs input to the figure processing device, wherein the figure processing device is capable of processing the figure according to claim 7. A computer-aided graphic creation device, characterized in that it is a processing device.