JPS6074088A - Extraction processing system for hidden-surface removed graphic - Google Patents

Abstract

PURPOSE:To perform hidden-surface removal at a high speed by reading and operating the state tree information on nodes having operators when storing types, etc., of primitives of a display body and deciding on whether respective points on test lines extending from an optional visual point are inside or outside the primitives or not. CONSTITUTION:When a body C is added to the body obtained by removing a body B from a body A and then a body is obtained by removing a body D from the resulting body, S1=A(-)B, S2=S1(+)C, and S3=S2(-)D are executed successively in order to obtain the desired graphic. Primitives A and B are so linked by a (-) arithmetic node as to obtain a master S1, which is so linked with a primitive C by a (+) arithmetic node as to obtain a master S2; and the master S2 and a primitive D are so linked by the (-) arithmetic node as to obtain a master S3, which is regarded as the root of a tree structure. The upward arithmetic of the root is performed by those pieces of master information.

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention relates to a hidden surface elimination figure extraction processing method, in particular, to a hidden surface elimination figure extraction processing method, in particular, to an arbitrary predetermined In the hidden surface removal figure extraction processing method that displays only the surfaces that appear in front when viewed from the viewpoint, for example in the form of two-dimensional figures, the test line from the viewpoint is extended to extract only the surfaces that appear in the front. The present invention relates to a hidden surface removal figure extraction processing method.

(B) Technical Background and Problems Conventionally, for example, an object 1 in the shape shown in FIG.
Extract object 3 by removing the part corresponding to object 2 from 1
As shown in the figure, hidden surface removal processing is performed on the object 5. In such a process, in principle, objects 1 and 2 shown in Figure 11 are displayed on a display, and objects 1 and 2 intersect as shown in Figure 1. For the parts, instructions are given in the form of planar figures to display them, and then unnecessary line segments are erased interactively, so that all desired figures can be extracted.

In order to simplify such interactive operations, it is known to use solid modeling languages with set operators. That is, by using the C5a (Constructive Solid 19 Geometry) data structure composed of three-dimensional primitives corresponding to each of the objects 1 and 2 above, and converting it into the B-RFP (Boundary Representation) data structure. For example, it is known to perform hidden surface processing after obtaining a collection of plane figures as shown in FIG. 1(6). However, in this process.

A conversion processing mechanism from C8G to B-REP-S is required, the processing time is long, and it is necessary to use four large-scale machines in total.

(0Objects and Structure of the Invention The present invention aims to solve the above point "f" by utilizing the result of extending the test line of the population from any predetermined viewpoint.

The purpose is to obtain hidden surface removal figures directly from the C8G data structure. For this purpose, the hidden surface removal figure extraction processing method of the present invention is as follows.

It has a primitive packet in which information including the type, position, tilt, and size of the primitive corresponding to each display object is stored, and has a set operator between the individual primitives read from the primitive packet. In a data processing device that has the function of executing operations based on a truth table corresponding to a solid modeling language, a point on a test line issued from an arbitrary predetermined viewpoint is within the above primitive. Provide an arithmetic unit on the test line that associates at least binary values depending on whether they are present or not, and performs the above operations on each binary value obtained based on each primitive, and emanates from the above viewpoint. For each of the plurality of test lines, the father point that intersects the first point of water is extracted for the object for which the above calculation has been performed, and the surface shape of the object for the result as seen from the above viewpoint is output. It is characterized by the fact that This will be explained below with reference to the drawings.

0 Embodiment of the Invention Fig. 2 is an explanatory diagram showing operations in a solid modeling language with set operators used in the present invention in the form of a truth table, and Fig. 3 is an explanatory diagram representing the operations in the solid modeling language with set operators used in the present invention.
gu - toi 7 ゛ ・ )kunor ・soto sue word φ Roronas - 4th day Nha Figure 4 (A) ＠
(C) ([) is an explanatory diagram explaining one embodiment of extraction processing according to the present invention, and FIG. 5 is a principle for extraction processing of another embodiment of the present invention? 6 shows a tree structure corresponding to the procedure shown in FIG. 5, and FIG. 7 shows an embodiment of the present invention that executes the process corresponding to the tree structure shown in FIG. 6.

In the calculations performed in the present invention, the conventional ◯ operation, ◯ operation, ◯ operation, etc. shown in FIG. 2 are used. The operation (1) considers objects 1 and 2 as shown in the 11th prisoner diagram, and expresses them generally to form a shape that is the sum of object A and object B (
It is an operation to obtain (so to speak, OR logic) f. Also, the operation is
Similarly, it is an operation to obtain a shape corresponding to the common part of object A and object B (so to speak, A AND logic). Furthermore, the e calculation is performed on a portion corresponding to object A from object B, as shown in FIG. 1(A).

This is an operation to obtain a completely removed shape. In addition, logic “1” in the diagram
” corresponds to a point inside the object, and a logical “0” corresponds to a point outside the object.

In order to represent Object 1 and Object 2 shown in Prisoner 11, primitive information corresponding to each object A, B, C, etc. is prepared, and these primitives are as shown in Figure 3. They are collectively stored on memory as a primitive packet 4. Each primitive includes <, (+) the primitive number corresponding to the object A, B, C..., (il) representing the shape of the object such as a sphere, rectangular parallelepiped, cone, or cylinder, as shown in Figure 3. Type, (lit) Center position that gives the location of the object ("+3' + z) + 0ψ Characteristic length that gives the size of the object (for spheres etc., it is given by the radius),
(V) Inclination representing the inclination state of the object, (vO above ○ left/right indication required for calculation, (vil)...
... etc. are described.

In the following, for the sake of simplicity, it is assumed that there is a rectangular prism-shaped object A and a rectangular prism-shaped object B, and that they are two-dimensional figures viewed from above, and the processing according to the present invention is performed with full reference to FIG. Explain.

Figure 4 (4) Assume that object A and object B exist one behind the other as shown in the diagram.

Consider the case where the result of the operation A■B is obtained. In the case of the present invention, as shown in FIG. 4(6), a plurality of test lines 5-1. ．． ······think of.

Each point on each test line gives a logic 1"4J or logic "O" depending on whether it is inside or outside the object for object A and object B, respectively.

When the second illustrated point α' is reached with respect to test line 5-1, corresponding to object A becomes a logical "l".

The logic is "0" corresponding to the object B, and the result is a logic "1" according to the explanatory diagram shown in FIG. Then, the point α′ where the result changes to logic “1” is the test −
It is registered as the "front point" on 2-in 5-1. Regarding the test line 5-2, the illustrated point C is extracted and registered as a "front point" on the test line as follows.

That is, at point α shown in Figure 9, 0-1= as shown in Figure 4, Figure 0.
0, and the result is a logical "0". Furthermore, when the object A is turned on, the logic becomes "1", but as shown in FIG. 4, 1-1=0, and the result remains the logic "0". Then, at point C, 1-0=1 as shown in FIG. 4, and the result is logical rlJ for the first time.91 Point C is registered as the "front point".

In this way, one front point is registered for each of a plurality of test lines, and by disabling these points, a desired hidden surface elimination figure is obtained.

Diagrammatically expressing the process corresponding to Fig. 4 (A) ■,
As shown in FIG. 4(C), the primitive ■ corresponding to object A and the primitive ■ corresponding to object B are connected in ■operation mate, and the result, that is, the object after the operation is obtained as "R". It can be expressed in the form of In addition, the fourth
In the case of the process corresponding to (2) in the figure, the above parent immediately becomes the answer (root).

Each object A, B in the form as explained in connection with FIG.
, C, . . ., objects A, B, C.

It is possible to obtain a hidden surface elimination figure for the case where ... are entangled with each other. However, as the number of entangled objects increases, the number of calculations increases dramatically. For this reason, the present invention provides a further advanced embodiment.

That is, if now objects A and B are shown in FIG. 5(4).

Consider a case where C and D are entangled, and an object C is added to an object obtained by removing object B from object A, and an object obtained by removing the object from this added object is obtained. This object corresponds to the shaded area in FIG.

The process to obtain this object is as shown in Figure 5). Sl = A OB Execute 2 and then in Figure 5 (0 as shown in Figure 52=Sl■C Execute 1 and then as shown in Figure 5, 8. 5s=Sz○D The desired figure is obtained as shown in FIG. 5 [F].

When the processing money described in connection with FIG. 5 is expressed in the tree structure described in connection with FIG. 4, it becomes as shown in FIG. 6. That is, (1) primitives ■ and ■ are combined by O operation node to obtain R81, and (If) parent S
l and primitive 0 are connected to the parent S by the operation node
2, and 011) The parent S2 and the primitive 0 are combined by the ○ operation node to obtain the parent S3, and Ov) The parent S3 is taken to be the root.

FIG. 7 shows an embodiment of the present invention in which processing corresponding to the tree structure shown in FIG. 6 is executed. Reference numeral 4 in the figure indicates a primitive number (test) corresponding to FIG.

6-1, 6-2, and 6-3 are residual information corresponding to each node, and 7 is an extraction intersection coordinate table.

First, primitive ■ and primitive ■ are read,
Remaining information 6- pointed to by each primitive
1 is used. Then, processing as shown in FIG. 5(6) is performed. That is, regarding test line 5, the calculation 51=001=0 is performed at point α shown in FIG. Since Sl is logic "0", the calculation 51=101=0 is further performed at the point shown in the figure. Since Sl is logical rOJ, the calculation 5x=1()O=1 is further performed at point C in the figure. Since Sl becomes logic "1", further calculations are stopped.

The calculation at the illustrated point d is omitted. Then, the coordinates at the position where the status "self" in the remaining information (SL) 6-1 shown in FIG. 7 becomes logical rlJ are provisionally registered.

Next, the remaining information 6-1 and the primitive O are read out, and the remaining information 6-2 pointed by them is used. Then, the processing as shown in FIG. 5(0) is performed on the same test line 5, ie.

Regarding test line 5, the following calculation is performed at point e shown in Ω in FIG. 5: 52=1×O=1. Since S2 becomes logic "1", further calculations are stopped and point 2 is shown at f.

The operations in da and h are omitted. Then, the coordinates at the position where the status "self" in the remaining information 6-2 becomes logical rlJ are compared with the previously temporarily registered coordinates, and the coordinates shown in FIG.
In the case of 0, the coordinates of point 1 are deleted and the coordinates of point 2 are temporarily registered.

Next, the remaining information 6-2 and primitive 0 are read out, and the remaining information 6-3 pointed to by these is used. Then, processing as shown in FIG. 50 is performed on the same test line 5. That is, regarding test line 5,
At the point t shown in FIG.

The calculation 53=001=0 is performed. Since S3 is logic "0", the calculation 53=101=0 is further performed at the point shown in the figure. Since S3 is logic "0", the following calculation is further performed at point k in the figure: 53=0.times.i=0. Since S3 is logic "0", 53=0θo= at the illustrated point t.

The following calculation is performed. And in this case.

It is revealed that on the test line 5, no object with a result corresponding to (((AeB) 2C>e)D) intersects. Then, on the extraction intersection coordinate table 7, the test
The column corresponding to line 5, for example, the rVJ column, has "No intersection"
is described.

In this way, the first intersection point is extracted for each test line, and the extracted intersection point 1 is placed on the locus table 7.

Written for each test line. Using this result,
The hidden surface elimination figure is drawn in a form in which the above-mentioned extracted intersection points are connected.

(2) Detailed Description of the Invention As described above, according to the present invention, the point that in the conventional case it was necessary to extract the data structure of the boundary expression is improved, and the amount of processing is significantly reduced.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram for explaining the prerequisite problem of the present invention. FIG. 2 is an explanatory diagram showing operations in a solid modeling language with set-o-rates used in the present invention in the form of a truth base; FIG. 3 is an explanatory diagram explaining the primitive packet referred to in the present invention; Figure 4 (4) ω) 00 is an explanatory diagram explaining one embodiment of extraction processing according to the present invention, Figure 5 is an explanatory diagram explaining the principle of extraction processing of another embodiment of the present invention, and Figure 6 is a tree structure corresponding to the procedure shown in Fig. 5,
FIG. 7 shows the configuration of an embodiment of the present invention for executing processing corresponding to the tree structure shown in FIG. In the figure, 1, 2.3 represent objects, 4 a primitive packet, 5 a test line, 6 new information, and 7 an extraction intersection coordinate table. Patent applicant: Fujitsu Ltd. Representative Patent Attorney Mori 1) Hiroshi (one other person) except Yasuyasu 2 Figure

Claims (2)

[Claims] (1) A primitive packet is provided in which information including the type, position, inclination, and size of the primitive corresponding to each display object is stored, and information is set between the individual primitives read from the primitive packet. In a data processing device having the function of executing operations based on a truth table corresponding to a solid modeling language with an oscillation, the test
Associate at least a binary value depending on whether a point on the line is inside or outside the primitive. 9. A test line arithmetic unit is provided to perform the above operation on each binary value obtained based on each primitive.9. 6. Each of the four test lines emanating from the above viewpoint. F word self! A hidden surface elimination figure extraction processing method characterized in that the first intersection point of an object resulting in a missing crab is extracted, and the surface shape of the object resulting in the result as seen from the above viewpoint is output. . (2) The test line operation unit reads the state tree information connected to the tree structure at the node having the operator for the primitive on which the operation is to be performed, and performs the operation in the direction toward the root of the tree structure. 2. A hidden surface removal figure extraction processing method according to claim 1, wherein calculation results at each node are used.