JP2001175879A - Method and device for three-dimensional graphics drawing process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speed up a drawing process for three-dimensional graphics. SOLUTION: An identical-point check means 6 decided whether or not projection coordinates of two successive vertexes of pixels constituting a three- dimensional body on a display screen have the same value and when so, a drawing process for the pixels having the two vertexes is omitted. When it takes a long time to perform the deciding process by the identical-point check means 6, the process of the check means 6 is skipped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional graphics drawing processing method and apparatus, and more particularly to a three-dimensional graphics drawing processing method and apparatus suitable for performing high-speed drawing by eliminating useless drawing processing. .

[0002]

2. Description of the Related Art There is an increasing movement to use three-dimensional graphics processing for various developments such as CAD / CAM / CAE / CG. For this reason, development of a rendering board or the like that further accelerates graphics drawing processing corresponding to OpenGL or the like as a graphics library is desired.

[0003] As one method of speeding up the rendering processing of three-dimensional graphics, hidden surface processing is well known. This hidden surface processing means that when a three-dimensional object created by a computer through arithmetic processing is projected and displayed on a display screen (two-dimensional screen) of a monitor, the back side of the three-dimensional object is not visible, so that drawing on the back side is performed. This is a technique for omitting processing. As described above, by eliminating unnecessary drawing processing, it is possible to speed up the three-dimensional graphics drawing processing.

[0004]

An image of a three-dimensional object created by a computer inside the computer is created by, for example, pasting simple triangular plane elements (patches). And
When projecting and displaying this three-dimensional object on a two-dimensional screen,
By comparing the coordinate values of each patch, it is determined whether or not the patch is on the surface side (display screen side) of the three-dimensional object, and the patch on the surface side is filled with display color or light source calculation processing. And the like, the patch is displayed on the two-dimensional screen, and the drawing process is omitted for the patch on the back side.

[0005] In recent years, the demand for speeding up the rendering processing of three-dimensional graphics has become more severe, and it is not possible to satisfy the demand only by omitting the rendering processing on the back side of the three-dimensional object as in hidden surface processing. is made of.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a three-dimensional graphics drawing processing method and apparatus for further speeding up.

[0007]

It is an object of the present invention to determine whether or not two consecutive vertices of a surface element constituting a three-dimensional object have the same coordinate value projected on a display screen. In the case of a value, this is achieved by omitting the drawing processing of the surface element having the two vertices.

Preferably, when it is estimated that the ratio of the number of the same coordinate value to the total number of the determinations is smaller than a predetermined ratio, the processing of the determination is skipped.

Further, it is preferable that the ratio at the time of performing the drawing processing of the three-dimensional object is stored, and the state change rate at the time of drawing the state change image of the three-dimensional object and the stored value are stored. The above estimation is performed from.

When a small triangle on the surface of the three-dimensional object comes directly in front of the monitor screen, the small triangle is displayed on the monitor screen. However, when the three-dimensional object rotates, the small triangle moves to the side. As you go, it becomes a flat micro triangle. When displaying a three-dimensional object created by a computer on a monitor screen, the number of dots that can be displayed even on a high-definition monitor is 1600 × 1200 dots or 1280 ×
1024 dots, which is finite.

For this reason, the coordinates of each point on the surface of the three-dimensional object are projected on the monitor screen by a matrix operation, but two vertices of the flat small triangle may be projected on the same dot on the monitor screen. . That is, the area of the minute triangle may become zero. Further, when the screen is switched to project a reduced image of the three-dimensional object on the monitor screen, one that can be recognized as three different vertices of a small triangle on the same-size image, but one of the monitor screen on the reduced image,
When projected onto a dot, the area of the minute triangle may become zero.

The present invention is characterized in that it is determined whether or not there is a region having an area of zero, and for a region having an area of zero, unnecessary drawing processing conventionally performed is omitted. This makes it possible to speed up the drawing process.

In order to smoothly represent a curved surface portion of a three-dimensional object, the above-mentioned patch may be reduced. However, the total number of three-dimensional object constituent points on a computer becomes enormous.
The time required for the above-described determination processing becomes long. Whether the calculation time is shorter when the useless drawing process is skipped, or the calculation time is shorter when the useless drawing process is performed without performing the determination process is the same coordinate value with respect to the total number of the above determination. It depends on the ratio (ratio) of the number. Therefore, when this ratio is smaller than the predetermined ratio, the determination process is not performed and the drawing process is executed even if it is useless, thereby avoiding a long calculation time.

Further, whether this ratio increases or decreases depends on the state change of the three-dimensional object to be drawn.
It can be estimated from this state change. For example, when drawing an image obtained by enlarging the three-dimensional object, the above ratio becomes smaller than before the enlargement, and when drawing a reduced image, the above ratio becomes larger than before the reduction. When drawing, the calculation time is shorter when the above-described determination processing is skipped, and when a reduced image is drawn, the calculation time is shorter when the above-described determination processing is performed and unnecessary drawing processing is skipped.

[0015]

An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram of a three-dimensional graphics drawing processing apparatus according to an embodiment of the present invention. This three-dimensional graphics drawing processing apparatus includes a matrix setting means 1, a matrix checking means 2, a management table 3, a screen switching means 4, and a coordinate conversion means for performing parallel projection coordinate conversion on input coordinate data. 5, the same point checking means 6, and the drawing processing means 7.

In this three-dimensional graphics drawing processing apparatus, the same-point checking means 6 determines in advance data that is invalid in drawing, that is, data having no area, and performs various geometric operations such as light source calculation, filling, and the like. By omitting the drawing process, the speed is increased.

Further, the matrix check means 2
With respect to the drawing data within the screen switching range, the ratio (ratio) of the number of data that becomes invalid in drawing is estimated in advance by using a set matrix, and it is checked whether or not the ratio exceeds a specific ratio. It is determined whether to activate the checking means 6. This makes it possible to determine in advance the increase / decrease of invalid data, suppresses the execution of the same point check processing at all times, executes the same point check processing only when necessary, and speeds up the processing. To achieve.

FIG. 2 is a flow chart showing the operation procedure of the matrix setting means 1, which includes a matrix concatenation processing step 21, a matrix setting processing step 22,
And a matrix check processing step 23.

The matrix setting means 1 first calculates various concatenation matrices necessary for the drawing process when various matrices are input (step 21). Then, in step 22, the calculated various matrices are stored in the management table 3, and in step 23, the matrix check unit 2 is started.

FIG. 3 is a flow chart showing the operation procedure of the matrix check means 2. The old value save processing step 31, the matrix Δ calculation processing step 32, the new Δ / old Δ calculation processing step 33, the zero area ratio It comprises an acquisition processing step 34, a predicted value calculation processing step 35, a determination processing step 36, a start flag ON setting processing step 37, and a start flag OFF setting processing step 38.

In the old value save processing step 31, the matrix check means 2 determines the size of the current matrix (Ma
trix △: The absolute value of the determinant value) is saved as the old value. Next, in step 32, the size of the new matrix is calculated and stored in the management table 3 as new △.

Next, at step 33, the new Matrix @
The value / old Matrix 旧 value is calculated and stored in the management table 3. Then, a numerical value of the number of objects having an area of zero / the total number is obtained from the management table 3 (step 3).
4) In the next step 35, a predicted estimation value is obtained by multiplying the calculation result of the new matrix Δ value / old matrix Δ value (the calculation result in step 33) by the value obtained in step 34.

Then, in step 36, by comparing the specific ratio value stored in the management table 3 with the predicted estimated value, it is determined whether it is meaningful to execute the same point check. According to the result, it is determined whether the activation flag is turned on or off. If it is determined that speeding up can be achieved by omitting useless drawing processing in the zero-area area, the process proceeds to step 37, in which the activation flag is turned ON, and it is determined that speeding up is achieved by not performing the same point check. Proceeds to step 38, turns off the startup flag, and ends this processing procedure.

FIG. 4 is a flow chart showing the operation procedure of the same point check means 6, which includes a flag check processing step 41, a determination processing step 42 for determining whether or not to execute the same point check, and a same point check execution processing step. 4
3, a determination processing step 44 of determining whether or not they are the same point;
It comprises a starting step 45 of the drawing process.

The input vertex coordinate data is converted into physical coordinates (coordinates of dots on the monitor screen) by the coordinate conversion means 5.
And the same point checking means 6 is activated. The same point checking means 6 first obtains the value of the activation flag from the management table 3 (step 41), and determines whether the value of the activation flag is ON or OFF, that is,
It is determined whether or not to execute the same point check (step 42). If the activation flag is ON, the process proceeds from step 42 to the next step 43, where the same point check is performed in accordance with the type of primitive constituting the three-dimensional object, the result of the same point check is obtained, and the same point counter is obtained. And the contents of the total counter are updated.

In the next step 44, it is determined whether the check result in the step 43 is "identical point" or "different point".
Then, the drawing processing means 7 is started, and in the case of "same point", the process is bypassed at step 44 and this processing procedure is ended. If the result of the determination in step 42 is that the start flag is OFF, the process proceeds from step 42 to step 45, in which the same point check processing is skipped, the drawing processing means 7 is started, and this processing procedure ends.

The screen switching means 4 in FIG. 1 holds the contents of the respective counters as old values and clears the new values to zero when a screen switching instruction is input. Thus, for example, when an enlarged image is displayed due to a matrix change, invalid data is reduced. Therefore, unnecessary same point check processing is skipped, and when a reduced image is displayed, invalid data is displayed. Since the number increases, it is possible to manage that the same point check processing is executed, thereby realizing high speed.

In the case of displaying a user's drawing data in a system for performing a three-dimensional graphics drawing process, the drawing process has been executed even for a drawing having no drawing area. And wasteful drawing processing time was spent, and an efficient and high-performance system could not be realized. However, in the present invention, unnecessary data transmission time and unnecessary drawing processing time can be omitted, so that the drawing processing can be sped up. Moreover,
Since it is estimated in advance whether it is faster to execute the useless drawing process or it takes time to determine whether the process is a useless drawing process, a more efficient system can be constructed.

[0029]

According to the present invention, useless drawing processing of a region having a display area of zero is skipped, so that the processing can be sped up. In addition, whether the skipping is performed by estimating in advance whether the processing speed is faster when the useless drawing process is skipped, or whether it takes too much time to determine whether the process is a useless drawing process or not. Therefore, it is possible to construct a flexible and more efficient system according to the situation.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a three-dimensional graphics drawing processing apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation procedure of a matrix setting unit in FIG. 1;

FIG. 3 is a flowchart illustrating an operation procedure of a matrix check unit in FIG. 1;

FIG. 4 is a flowchart illustrating an operation procedure of the same-point checking unit in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Matrix setting means 2 Matrix checking means 3 Management table 4 Screen switching means 5 Coordinate conversion means 6 Same point checking means 7 Drawing processing means

Claims (6)

[Claims] 1. A method in which two consecutive surface elements constituting a three-dimensional object are used.
Determining whether or not the projection coordinate values of the vertices on the display screen have the same coordinate value, and omitting the rendering of the surface element having the two vertices if the coordinate values are the same; Original graphics drawing processing method. 2. The three-dimensional graphics drawing method according to claim 1, wherein a ratio of a number assumed to be the same coordinate value to a total number of determinations is estimated to be smaller than a predetermined ratio. Is a step of skipping the process of making the determination. 3. The three-dimensional graphics drawing processing method according to claim 2, wherein the ratio when the drawing processing of the three-dimensional object is performed is stored, and a state change image of the three-dimensional object is drawn. A three-dimensional graphics rendering processing method, wherein the estimation is performed from the state change rate at the time and the stored value. 4. A method in which two continuous surface elements constituting a three-dimensional object are provided.
Determining means for determining whether or not the projection coordinate values of the vertices on the display screen have the same coordinate value; and means for omitting the drawing processing of the surface element having the two vertices if the same coordinate value is obtained. A three-dimensional graphics drawing processing device, comprising: 5. The three-dimensional graphics drawing processing apparatus according to claim 4, wherein a ratio of a number assumed to be the same coordinate value to a total number of the determination is estimated to be smaller than a predetermined ratio. Is a three-dimensional graphics drawing processing apparatus, which skips the processing of making the determination. 6. The three-dimensional graphics drawing processing device according to claim 5, wherein the ratio when the drawing processing of the three-dimensional object is performed is stored, and a state change image of the three-dimensional object is drawn. The three-dimensional graphics drawing processing device, wherein the estimation is performed from the state change rate at the time and the stored value.