JPH09245180A - Polygon paint out method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce processing time by reducing the overlapped painting of the same area and the paint out of the outside of a polygonal area as far as possible in a polygon paint out method. SOLUTION: A polygon 1 is decomposed into a triangles 2 and 3 in advance and stored in a data buffer 100 as paint out patterns 201. In the paint out processing of the triangle 2 at first, data (null data) is already read out from a dot memory 400 dot information of the paint out pattern 201 corresponding to the triangle 2 is read out from the data buffer 100 to exclusively OR both of them to write in the dot memory 400 again. In the paint out processing of the triangle 3 continually, dot information corresponding to the triangle 2 already written in the dot memory 400 is read out and dot information corresponding to the paint out pattern 201 corresponding to the triangle 3 is read out from the data buffer 100 to exclusively OR both of them to write into the dot memory 400.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polygon filling method in a graphics processing device or the like.

[0002]

2. Description of the Related Art Heretofore, as a polygonal filling method of this kind, a method described in Japanese Patent Laid-Open No. 3-108081 has been known.

FIG. 2 shows a polygon to be filled, and FIG. 9 shows the filling process. In FIG.
A, B, C and D are coordinates (0, 2), (1,
0), (2,2), (3,0) polygon vertices,
Is a polygon with those vertices.

In FIG. 9, 4 is a rectangular area having the maximum x and y coordinates and the minimum x and y coordinates of polygon 1 as diagonals, and 5 includes the side AB of polygon 1 and the right end coincides with the right end of rectangular area 4. Top base = 3, bottom base = 2, height = 2 trapezoid, 6 includes the side BC of polygon 1 and the right end matches the right end of the rectangular region 4 =
1, trapezoid with bottom = 2 and height = 2, 7 is side CD of polygon 1
And a right edge of the rectangle 1 whose height matches the right edge of the rectangular area 4 = 1, and a height of 2; a reference numeral 8 includes a side DA of the polygon 1; the right edge of which matches the right edge of the rectangular area 4; It is a triangle of 2. In this conventional example, the basics of filling are trapezoidal and triangular.

In the filling process, first, the trapezoid 5 shown in FIG. 9A is filled. By this filling processing, the data already written in the memory is read out, and the data shown in FIG.
The exclusive OR with the pattern of and is written again in the memory. FIG. 9B shows the result of this filling processing, which is written in the memory. Subsequently, the trapezoid 6 filling process shown in FIG. 9C is performed. The data of FIG. 9B already written in the memory is read by this filling processing, and the exclusive OR is taken with the pattern of FIG. 9C,
Perform the operation to write to the memory again. At this time, the area that overlaps with the already filled portion returns to the data before being filled (exclusive OR 1 + 1 = 0).

FIG. 9D shows the result of this filling processing. Subsequently, the filling process of the triangle 7 shown in FIG. 9E is performed. In this filling processing, the data of FIG. 9D already written in the memory is read, the exclusive OR is taken with the pattern of FIG. 9E, and the operation of writing again in the memory is performed. At this time, there is no area that overlaps the already-painted portion. FIG. 9F shows the result of this filling processing. Then, the filling process of the triangle 8 shown in FIG.9 (g) is performed. In this filling processing, the data already written in the memory in FIG.
The data of (f) is read, the exclusive OR is obtained with the pattern of FIG. 9 (g), and the operation of writing again in the memory is performed.
At this time, the area that overlaps with the already filled area returns to the data before being filled (1 + 1 = exclusive OR).
0). In this way, finally, the filled polygon as shown in FIG. 9 (h) is completed.

In the above case, the total area subjected to the filling processing is the total of the graphic areas shown in FIGS. 9 (a), (c), (e), and (g), which is 12, but is the final value. The area filled in is 2. The number of filling processes is four.

[0008]

In the above-mentioned conventional method, the same area must be repeatedly overpainted, or the area outside the polygonal area which should not be originally filled must be filled up. Therefore, extra processing time is required. There is a problem that it will occur.

An object of the present invention is to reduce over-painting of the same area and painting outside the polygonal area as much as possible to shorten the processing time.

[0010]

In order to solve this problem, the present invention provides a basic filling pattern, not a trapezoid and a triangle, but only a triangle.

As a result, the filling outside the polygonal area can be reduced, and the processing time can be shortened.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A polygon filling method according to claim 1 of the present invention is a polygon filling method for forming a polygon whose inside is filled with a filling pattern on a memory. When disassembling only into triangles and forming these as fill patterns, and when sequentially expanding a plurality of triangles in memory, fill each triangle while taking the exclusive OR of the fill pattern of each triangle and the data in memory. Since the basic filling pattern is not a trapezoid and a triangle but only a triangle, there is an effect that it is possible to reduce overpainting of the same area and filling outside the polygonal area that does not need to be filled. .

The polygon filling method according to a second aspect of the present invention is the method according to the first aspect, wherein when the polygon is decomposed into a plurality of triangles, (1) the triangles may overlap or may not overlap. There is no area inside the polygon that does not belong to any triangle. (2) All vertices of the polygon are included in the vertices of any triangle. However, one vertex of a polygon may be included in the vertices of a plurality of triangles. (3) A figure formed from the outermost periphery of a figure formed by a triangle group includes the original polygon, (4)
There is an odd number of triangles that include a polygonal side, (5)
The feature is that when a triangle has a side that a polygon does not have, the number of triangles that include that side is an even number. It has the effect that a polygon can be decomposed into triangles so that external painting errors do not occur.

An embodiment of a polygon filling method according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the functions required to implement the polygonal fill method. In FIG.
Reference numeral 100 is a data buffer that stores coordinate data of each vertex of an arbitrary polygon that is fetched from the outside by various methods as polygon information 101, and reference numeral 200 is a polygon related to the polygon information 101 based on the polygon information 101. Is decomposed into a plurality of required triangles according to the following conditions (1) to (5),
Polygon decomposition means for calculating the coordinates of each vertex of each triangle, 2
Reference numeral 01 is triangle information which is coordinate data of each vertex of each triangle obtained as described above, and this triangle information is stored in the data buffer 100 as a fill pattern 201. Reference numeral 300 is a fill processing means for performing a fill processing on a given polygon having an arbitrary shape in accordance with a predetermined procedure, and 400 is a dot memory for storing dot information of the result of the fill processing. Filling processing means 300
Reads the dot information in the middle of the filling process from the dot memory 400, reads the dot information of the filling pattern 201 from the data buffer 100, takes the exclusive OR of both, and stores the dot information of the filling process result in the dot memory 400. The process of allowing is repeated several times.

FIG. 3 shows the polygon 1 of FIG. 2 decomposed into two triangles. In FIG. 3, reference numeral 2 is a triangle (ABC) including the vertices A, B and C of the polygon 1, and 3 is a triangle (CDA) including the vertices C, D and A of the polygon. The following conditions are required for this decomposition.

(1) The triangles may be non-overlapping or multi-overlapping, but there must be no region inside the polygon that does not belong to any triangle.

(2) All the vertices of a polygon are included in the vertices of any triangle. However, one vertex of a polygon may be included in the vertices of a plurality of triangles.

(3) The figure formed from the outermost periphery of the figure formed by the triangle group includes the original polygon.

(4) The number of triangles including a polygonal side is odd.

(5) When a triangle has a side that a polygon does not have, the number of triangles including that side is even.

Under the above conditions, the polygonal triangle decomposition is performed by the polygon decomposition means 200, and the obtained triangles are stored in the data buffer 100 as the filling pattern 201. By satisfying the conditions (1) to (5), the polygon can be decomposed into triangles so as to prevent unpainted portions inside the polygon and incorrect coating outside the polygon.

The graphic formed by the triangles 2 and 3 satisfies all the above conditions. Although the triangles 2 and 3 overlap, there is no gap inside the polygon 1. Since vertex B of polygon 1 is included in triangle 2, vertex D is included in triangle 3, and vertices A and C are included in triangle 2 and triangle 3, respectively, all vertices of polygon 1 are It is included in the triangle. The outermost periphery of the figure in which the triangle 2 and the triangle 3 overlap each other includes the polygon 1. The sides AB and BC of the polygon 1 are included in the sides of the triangle 2, and the sides CD and DA are included in the sides of the triangle 3. That is, each side of polygon 1 is 1
(Generally an odd number) of triangles.
The side AC not including the polygon 1 is included in both sides of the triangle 2 and the triangle 3. That is, this side is included in the sides of two (generally even) triangles. Note that the conditions (1) and (5) will be supplemented later.

FIG. 4 shows the process of the filling processing by the painting processing means 300. In the filling process, first, the filling process of the triangle 2 is performed. This triangle has a base = 2,
Height = 2. In this filling process, the dot information (full sky state) already written in the dot memory 400 is read out, and the data buffer 100 shown in FIG.
The dot information of the filled pattern 201 representing the triangle 2 shown in (a) is read out, the exclusive OR of the two is taken,
As shown in FIG. 4B, the operation of writing the dot information as the result of the filling processing into the dot memory 400 again is performed.

Subsequently, the triangle 3 is filled. The triangle 3 has a base = 2 and a height = 2. In this filling processing, the dot memory 400 shown in FIG. 4B which has already been written in the dot memory 400 is read out, and the dot information of the filling pattern 201 shown by the triangle 3 shown in FIG. 4C is read out from the data buffer 100. Then, the exclusive OR of both is taken (at this time, the area that overlaps with the already filled portion returns to the data before being filled (exclusive OR 1 + 1 = 0)), and the dot information of the filling processing result is displayed. The operation of writing to the dot memory 400 again is performed as in 4 (d).

In this way, finally, a filled polygon as shown in FIG. 4D is completed. In this case, the total area subjected to the filling processing is the sum of the graphic areas in FIGS. 4A and 4C, which is 4, but the final filled area is 2. Further, the number of times of filling processing is two. As described above, according to this embodiment, the number of times the same region is overpainted and the area thereof, and the area outside the polygonal area that originally does not need to be filled are reduced and the processing time is shortened, as compared with the conventional example. The condition (4) when the polygon is decomposed into a plurality of triangles will be supplemented below. The condition (4) is that “the number of triangles including a polygonal side is an odd number”.

For example, five vertices A as shown in FIG.
Given a polygon 10 with B, C, D and E.
Then, as shown in FIG.
Triangle 11 with BE, triangle 12 with vertex BCD,
It is decomposed into a triangle 13 having a vertex ACE, a triangle 14 having a vertex ADE, a triangle 15 having a vertex ACD, and a triangle 16 having a vertex ECD. In this case, the side AE and the side CD are included in a plurality of triangles, but the side AE is the triangle 11,
It is included in three, that is, an odd number of triangles 13 and 14, and the side CD is also included in three, that is, an odd number of triangles 12, 15, and 16.

6 (a) to 6 (f) show a process in which the above six triangles 11 to 16 obtained by the decomposition are sequentially filled as a filling pattern. It can be seen that the dot information of the finally obtained filling processing result in FIG. 6F accurately fills the polygon 10 given in FIG. 5A.

In the case of the polygon 10 of FIG. 5A, however, it is sufficient to decompose it into two triangles, the triangle 11 having the vertex ABE and the triangle 12 having the vertex BCD.
The wording of the claims is generalized to include all the redundant ones.

Next, the condition (5) for decomposing a polygon into a plurality of triangles will be supplemented. The condition (5) is that "if a triangle has a side that a polygon does not have, the number of triangles including that side is an even number".

For example, six vertices A as shown in FIG.
It is assumed that an empty polygon 20 having B, C, D, E and F is given. Then, as shown in FIG. 7B, a polygon 21 having a vertex ABD, a triangle 22 having a vertex CBD, a triangle 23 having a vertex FBD, and a vertex EBE are formed on the polygon 20.
To a triangle 24 with. In this case, the side BD is a side that the polygon 20 does not have, but this side BD is a triangle 2
It is included in four, that is, an even number of triangles 1, 22, 23, and 24.

8 (a) to 8 (d) show a process in which the above four triangles 21 to 24 obtained by the decomposition are sequentially filled as a filling pattern. It can be seen that the dot information of the filling processing result finally obtained in FIG. 8D accurately fills the polygon 20 given in FIG. 7A.

[0033]

As described above, according to the present invention, it is possible to reduce the number of times the same area is overpainted, the area thereof, and the painting outside the polygonal area which originally does not need to be filled, and to shorten the processing time. The effect of being able to be obtained is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing functions necessary for carrying out a polygon filling method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a diagram of a polygon to be filled.

FIG. 3 is a diagram showing a state in which the polygon of FIG. 2 is decomposed into two triangles in the embodiment.

FIG. 4 is an explanatory diagram showing a process of polygon filling processing according to the embodiment.

FIG. 5 is a diagram showing a state of another given polygon and its triangular decomposition.

FIG. 6 is an explanatory diagram showing a process of the polygon filling method of FIG.

FIG. 7 is a diagram showing still another given polygon and its triangular decomposition state.

FIG. 8 is an explanatory diagram showing a process of the polygon filling method of FIG. 7.

FIG. 9 is an explanatory diagram showing a process of a conventional polygon filling method.

[Explanation of symbols]

1,10,20 ... Polygon 2,3,11,12,13,14,15,16,21,
22, 23, 24 ... Triangle 100 ... Data buffer 101 ... Polygon information 200 ... Polygon decomposition means 201 ... Fill pattern 300 ... Fill processing means 400 ... Dot memory

Claims (2)

[Claims] 1. A polygon filling method for forming a polygon whose inside is filled with a filling pattern on a memory, wherein the polygon is decomposed into only a plurality of triangles to form a filling pattern on a memory. A polygon filling method characterized in that when a plurality of triangles are sequentially expanded, each triangle is filled while taking the exclusive OR of the filling pattern of each triangle and the data on the memory. 2. When decomposing a polygon into a plurality of triangles, (1) the triangles may or may not overlap, but there is a region inside the polygon that does not belong to any triangle. (2) All vertices of a polygon are included in the vertices of any triangle. However, one vertex of a polygon may be included in the vertices of a plurality of triangles. (3) A figure formed from the outermost circumference of a figure formed by a triangle group includes the original polygon. (4) Decompose under the condition that the number of triangles that include a side of a polygon is an odd number, (5) If a triangle has a side that a polygon does not have, the number of triangles that include that side is an even number. Claim 1 characterized by the above.
The polygon filling method described in.