JPH064679A - Image processor - Google Patents

Abstract

PURPOSE:To provide an image processor which can plot a polygon that is subjected to anti-aliasing at high speed with less hardware amount by simultaneously executing an anti-aliasing processing and the judgement processing of paint out area on an image processor which efficiently removes the aliasing of a boundary in the paint out or shading of the polygon. CONSTITUTION:A calculation means 1 which sequentially calculates the linear expression of a two-dimensional coordinate system in accordance with the respective sides of the polygon, judges a relative position relation of plotting points with respect to the polygon and obtains the displacement of the respective plotting points from the sides of the polygon and a conversion means 5 changing the color or gradation of the plotting point near the sides of the polygon based on displacement obtained in the calculation means 1 are provided. Then, the internal part of the polygon is painted out or it is shaded on a bit map memory.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus for processing image information such as figures and images in computer graphics, and more particularly, to efficiently perform boundary aliasing in polygonal filling or shading. The present invention relates to an image processing device for removing.

[0002]

BACKGROUND OF THE INVENTION In computer graphics (CG) techniques, an image is treated as a bitmap, a collection of pixels arranged in two dimensions. Therefore, when the polygon is represented on the bitmap, the boundary portion becomes jagged as shown in FIG. This phenomenon is called jaggies or aliasing.

Normally, by combining with the gradation of pixels, for example, as shown in FIG. 17, points near the side (see FIG. 17).
The middle (x mark) can remove the aliasing at the time of display by drawing by changing the gradation. The technique used in this case is anti-aliasing.
) Or area sampling, among which the method by Goupta, Sproull is often used.

In the Goupta-Sproull method, the pixels have a cone-shaped distribution with a radius of 1 around the pixel center (see FIG. 19), and the volume of the cone 311 is
The gradation is determined depending on how much part is inside the polygon. That is, this method removes aliasing by using a conical spatial filter to drop high-frequency components in the spatial frequency distribution.
According to this method, since the filter function is symmetrical about the center, it is a function of the distance from the center, and by storing the value in the table in advance, the processing is performed in the following procedure. Can be done.

(1) The distance from the center of each pixel to the side is obtained.

(2) Based on this distance, the gradation to which the pixel is painted is determined by referring to a table.

For example, consider points A, B, C, and D with respect to a side 301 having a polygon in FIG.
And C, and the distance dB from each point to side 301
, And dC, the gradation is obtained by referring to the table.
Since the point D is a point inside the polygon, it is painted in the color of the polygon, and the point A is an outside point and is not painted.

The step (1) is performed by calculation using only sequential addition along each side of the polygon.

On the other hand, in the polygonal filling process, it is necessary to determine the area to be filled. In the area judgment,
As shown in FIG. 20, for each value of y, the points at both ends on the x-direction scan line are obtained, and the triangle 321 is painted. In the above Goupta-Sproull method, since the gradation value for anti-aliasing is obtained along the side, the processing is different from the area determination, and the required gradation is different, so the processing is complicated. It was difficult to make it into hardware.

[0010]

As described above, in the conventional image processing apparatus, for example, the Goupta-Sproull method is used as the anti-aliasing technique, and the gradation value for anti-aliasing is the edge value. In addition, since the processing is different from the determination of the area to be filled in the filling processing, and the required gradation is different, the processing is complicated and hardware implementation is difficult.

The present invention solves the above problems,
It is an object of the present invention to provide an image processing device capable of drawing an anti-aliased polygon at high speed with a smaller amount of hardware by simultaneously performing the anti-aliasing process and the region determination process in filling.

[0012]

In order to solve the above-mentioned problems, the first feature of the present invention is that, as shown in FIG. 1, a linear expression of a two-dimensional coordinate system is set for each side of a polygon. Calculation means 1 for sequentially calculating and determining the relative positional relationship of the drawing point with respect to the polygon, and obtaining the displacement of each drawing point from the side of the polygon.
And a conversion means 5 for changing the color or gradation of a drawing point near the side of the polygon based on the displacement obtained by the calculation means 1, and the inside of the polygon on the bitmap memory. Filling or shading.

A second feature of the present invention is that in the image processing apparatus according to claim 1, the conversion means 5 is a ROM.
Alternatively, it is composed of a RAM table.

A third aspect of the present invention is the claim 1 or 2.
The image processing device described in 1.
Is a digital differential analyzer or linear interpolation circuit.

According to a fourth aspect of the present invention, in the image processing apparatus according to claim 1, 2 or 3, the calculation means 1 defines a rectangular area including the polygon or overlapping the polygon. However, scanning in two directions in the two-dimensional coordinate system is performed only inside the rectangular area.

A fifth feature of the present invention is the image processing apparatus according to claim 1, 2 or 3, wherein the calculation means 1 defines a rectangular area including the polygon or overlapping the polygon. However, scanning in two directions in the two-dimensional coordinate system is performed within the rectangular area and only within the polygon.

A sixth feature of the present invention is that, as shown in FIG. 1, a linear expression of a two-dimensional coordinate system is sequentially calculated for each side of a straight line having a width, and Both sides of the straight line are determined based on the displacement determined by the calculation means 1 by determining the relative positional relationship with respect to both sides of the straight line and determining the displacement of each drawing point from the both sides of the straight line. And a conversion means 5 for changing the color or gradation of the drawing point near the side of the above, and draw an anti-aliased straight line.

The seventh feature of the present invention is, in the image processing apparatus according to claim 6, the calculation means 1 defines an arbitrary rectangular area, and two directions in a two-dimensional coordinate system are defined inside the rectangular area. Is to scan.

Further, an eighth feature of the present invention is that, as shown in FIG. 11, a linear expression of a two-dimensional coordinate system is sequentially calculated corresponding to each side of a polygon, and a drawing point is relative to the polygon. Calculating unit 1 for determining the physical positional relationship and obtaining the displacement of each drawing point from the side of the polygon, a value to be written in the bit map memory based on the displacement obtained by the calculating unit 1, and the address Ratio determining means 5 and 55 for determining the ratio to be mixed with the value written in
The inside of the polygon is filled or shaded on the bitmap memory.

[0020]

The image processing apparatus of the present invention is characterized in that the calculation for the area determination processing and the anti-aliasing processing in the polygonal filling are simultaneously performed by the same hardware.

First, the area determination processing for filling will be described. Each side of the polygon is represented by the following straight line formula.

F (x, y) = a × x + b × y + c = 0 (1) Here, it is assumed that the sign is defined so as to satisfy the following expression.

F (x, y)> 0 polygon inside f (x, y) = 0 side f (x, y) <0 polygon outside (2) Further, in equation (1), it is a positive number as a whole. You have the freedom to multiply
This is normalized so that when the long axis of the side straight line is the X axis, b = ± 1 (3) When the long axis of the side straight line is the Y axis, a = ± 1. Therefore, the major axis is X-axis: f (x, y) = a × x ± y + c (4) The major axis is Y-axis: f (x, y) = ± x + b × y + c (5).

By knowing the sign of f (x, y) for each side of the polygon, it can be determined whether the point (x, y) is located inside the polygon. That is, f for all sides
The point where (x, y)> 0 is the point inside the polygon.

On the other hand, the value of f (x, y) is the point (x, y).
Represents the distance (signed value) to the side in the uniaxial direction of. For example, when the polygon has a side 201 as shown in FIG. 2, the distance dYA in the Y-axis direction from the points A and B to the side 201.
And dYB are given by f (xA, yA) and f (xB, yB). These are not the vertical distances to the side 201, but by using them as the keys of the conversion means (table ROM) 5 together with the inclination of the side 201, the gradation value can be obtained.

In the case where the value of f (x, y) is within a certain range, for example, -1≤f (x, y) <1, when changing the gradation as the antialiasing processing target, one side is focused on. And perform the following processing.

That is, when f (x, y) <-1, it is outside the polygon and is not drawn. When -1≤f (x, y) <1, it is near the side and the gradation is changed. Draw (however, if other sides are inside the polygon), and if f (x, y) ≧ 1, draw as being inside the polygon (however, if other sides are also inside the polygon).

In the image processing apparatus having the first, second, third, fourth and fifth features of the present invention, the calculation means 1 corresponds to each side of the polygon and the linear expression of the two-dimensional coordinate system is used. Is calculated sequentially, the relative positional relationship of the drawing point with respect to the polygon is determined, and the displacement of each drawing point from the side of the polygon is obtained. Based on this displacement, the converting means 5 calculates the polygon Colors or gradations of drawing points near the sides are changed to fill or shade the inside of the polygon on the bitmap memory. Note that the calculation unit 1 defines a rectangular area including the polygon or overlapping the polygon, and scans in two directions in a two-dimensional coordinate system only within the rectangular area or within the rectangular area. It is also possible to do it only inside the polygon.

As a result, it is possible to commonly carry out the calculation processing of the displacement for anti-aliasing and the judgment processing of the internal area of the polygon in the filling, which are conventionally independent processing, and with a smaller amount of hardware. , It is possible to draw a polygon with anti-aliasing processing at high speed.

Further, in the image processing apparatus having the sixth and seventh characteristics of the present invention, the calculating means 1 sequentially calculates the linear expressions of the two-dimensional coordinate system corresponding to both sides of the straight line having the width. Also, the relative positional relationship of the drawing points with respect to both sides of the straight line is determined, and the displacement of each drawing point from both sides of the straight line is obtained, and based on this displacement, both sides of the straight line are converted by the converting means 5. The color or gradation of the drawing point near the side of is changed to draw an anti-aliased straight line. The calculation means 1 defines an arbitrary rectangular area,
It is also possible to scan in two directions in a two-dimensional coordinate system inside the rectangular area.

As a result, the displacement calculation process for anti-aliasing and the determination process of the internal area of the straight line having the width in the filling can be performed in common, and the anti-aliasing process can be performed at high speed with a smaller amount of hardware. You can draw a straight line.

Further, in the image processing apparatus of the eighth feature of the present invention, the calculation means 1 corresponds to each side of the polygon and outputs 2
The linear equation of the dimensional coordinate system is sequentially calculated, the relative positional relationship of the drawing point with respect to the polygon is determined, the displacement of each drawing point from the side of the polygon is determined, and based on this displacement,
The ratio determining means 5 and 55 determine the ratio at which the value to be written in the bit map memory and the value already written in the address are mixed, and the inside of the polygon is filled or shaded in the bit map memory. I am trying to attach it.

As a result, the image processing apparatus having the above-mentioned first to seventh characteristics can be applied to the polygon shading processing of a three-dimensional graphic.

[0034]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an image processing apparatus according to the first embodiment of the present invention.

In the figure, the image processing apparatus of the present embodiment is an area DDA (Digital Differential Analyzer) for calculating the value of the linear expression f (x, y) for each side of the polygon.
A linear interpolation circuit) 1, an address generator 9 for generating a drawing address ADR, a tilt register 3 for holding the tilt of each side of the polygon, and a table ROM for holding the gradation value.
5 and a selector 7.

In the address generator 9, for example, as shown in FIG. 6, a rectangular area 20 containing a polygon 203 to be drawn.
5 addresses are sequentially generated. Further, a signal XYSEL indicating whether the address changing direction is the X-axis direction or the Y-axis direction is output to the area DDA1, and in the area DDA1,
The linear equation f (x, y) is calculated according to the signal XYSEL.

A signal indicating which side of the polygon is near the point is output from the area DDA1, and the side selection signal ESEL for selecting the output of the tilt register 3 configured by the register file is used as the signal. Becomes

From the area DDA1, the side selection signal ES
The displacement signal VAL representing the value of the linear expression f (x, y) in the range of -1 to 1 is output for the side designated by EL, and the slope value GR of the side selected by the side selection signal ESEL is output.
Table ROM5 by combining D and this displacement signal VAL
The key is.

The gradation value C read from the table ROM 5 is input to the selector 7. The other input of the selector 7 is a signal representing gradation 1, and the area determination signal P indicating that it is near the side from the area DDA1 is input as a selection signal and selectively output. The output of the selector 7 becomes the write data WDm for the image memory (not shown).

Further, the area DDA1 outputs an area determination signal R indicating that it is inside the polygon or near the side, and is used as a write enable signal for the image memory.

With this configuration, in this embodiment, the anti-aliased polygon is drawn as follows.

That is, in the address ADR generated by the address generating unit 9, drawing is performed on the inside of the polygon and the points near the side. For the points inside the polygon, the data to be drawn has a gradation of 1, but for the points near the side, the values in the linear expression f (x, y) of the side and the slope of the side are used to make a table ROM5. It is the obtained gradation value C. As described above, in the image processing apparatus of this embodiment, the distance calculation between the point and the side for anti-aliasing is performed by the same hardware.

Next, the area DDA1 of this embodiment will be described in detail. It should be noted that here, a case of handling a triangle as a polygon will be described, but extension to a general polygon is easy.

FIG. 3 shows a detailed configuration diagram of the area DDA1.
In the same figure, the area DDA1 has three sides DDA corresponding to each side of the triangle, that is, the first side DDA11 and the second side DD.
A12, a third side DDA 13, a priority encoder 15, a selector 17, and an area determination circuit 19.

From each side DDA 11, 12, and 13,
Signals P0, P1, and P2 indicating that the drawing point is near the side, signals Q0, Q1, and Q2 indicating that the drawing point is inside the triangle with respect to the side, and a straight line for each side. A decimal part V0 containing the sign of the value of the expression f (x, y),
V1 and V2 are output respectively.

A signal P indicating that the drawing point is near the side
0, P1, and P2 are priority encoders 15
Results in a 2-bit signal. Normally, the signals P0, P
Although 0 or 1 of 1 and P2 is "1", two of them may be "1" in the vicinity of the apex, and thus the priority encoder is used.

The output of the priority encoder 15 is not only the edge selection signal ESEL to the outside, but also the fractional parts V0, V1 and V2 containing the sign of the value of the linear expression f (x, y) in the selector 17. It also serves as a selection signal for selection. The output of the selector 17 is the displacement signal V
Become AL.

In the area determination circuit 19, the signals P0, P1 and P2 indicating that the drawing point is near the side and the signal Q indicating that the drawing point is inside the triangle with respect to the side.
Inputting 0, Q1, and Q2, the area determination signals P and R are generated by the following logic.

[0050]

[Equation 1] R = (P0 + Q0) ・ (P1 + Q1) ・ (P2 + Q2) Q = Q0 ・ Q1 ・ Q2 P = R ・ / Q (6)

Here, the symbol ".multidot." Indicates a logical product, "+" indicates a logical sum, and "/" indicates a logical negation.

FIG. 4 is a detailed block diagram of the sides DDA 11, 12 and 13. As shown in the figure, the sides DDA11, 1
2 and 13 are registers YA, XA, YC, and X
C, selectors 21 and 22, an adder 23, and an output value generation circuit 25.

Registers YA, XA, YC, and XC are
A value can be set at the start of the operation by the external data bus DBUS. Registers YA and XA
Through the selector 21 and registers YC and YC
Becomes an input to the adder 23 via the selector 22. still,
The registers YA, XA, YC, and XC, the selectors 21 and 22, and the adder 23 are commonly configured by 1 bit. The MSB (most significant bit) is a sign bit sign and the lower m bit is a decimal part. dec, 1-m-1 bits between them are the integer part int, and are in the two's complement representation.

The two selectors 21 and 22 have in common:
By the selection signal XYSEL from the address generation circuit 9,
When scanning in the X-axis direction (in FIG. 6), the registers XA and XC are selected, and when proceeding to the next line in the Y-axis direction, the registers YA and YC are selected.
When the registers XA and XC are selected, the addition result is stored in the register XA, but when the registers YA and YC are selected, the addition result is stored in both the registers XA and YA. The registers XC and YC are constant registers in which a and b in the linear equation of the side (Equation (1)) are set.

The output value generation circuit 25 has a logical configuration as shown in FIG. 5, and the drawing point is near the side from the sign bit sign, the integer part int, and the decimal part dec of the output XAo of the register XA. Signal Pi (i = 0,
1, 2), a signal Qi indicating that the drawing point is inside the triangle, and a fractional part Vi including the sign of the value of the linear expression f (x, y) of the side are generated.

In this embodiment, both the value of the straight line side expression f (x, y) and the slope are used as the keys of the table ROM 5, but the slope can be omitted. In this case, the quality of the generated image is slightly deteriorated. Also, table ROM
It is also possible to omit 5 and use the value of the linear expression f (x, y) of the side as it is as the gradation value. Furthermore, the table RO
It is also possible to configure M5 with RAM, or with PLA or random logic.

In the present embodiment, the entire rectangular area including the polygon is scanned. However, the scanning method is changed so that only the polygonal portion is scanned so that the drawing time can be reduced. It is also possible to do so. This modification will be described in detail below.

In this modification, as shown in FIG. 7, the area DD is scanned while scanning the triangle 211 in the following order.
The value of the linear expression f (x, y) of the side is calculated using A1. At this time, for each line, there is one point to store information for DDA calculation of the next line.

(1) If the scan start point in the X-axis direction is within the area, it is set as a point to be stored (point P1 in FIG. 7).

(2) The calculation is carried out in the X-axis direction, and the points that enter the area for the first time are set as points to be stored (points P2 and P3).

(3) When the calculation is continued and the user goes out of the area,
The processing of that line is completed.

(4) Move one point in the Y-axis direction from the saved point.

(5) The moved point (points P1y, P2y, P3
From y), a new scan in the X-axis direction is performed.

The above processing is repeated for the number of lines.

In this modification, it is necessary to determine the changing direction of Y in the direction in which the X coordinate increases on the left side of the triangle. Therefore, for example, in the case of the triangle 221, as shown in FIG. 8, the triangle is divided into two parts, and the upper half is scanned in the direction in which the Y coordinate decreases, and the lower half is scanned in the direction in which the Y coordinate increases.

When the method of this modification is adopted, the side DDA
11, 12, and 13 are configured as shown in FIG. Register SA instead of register YA in FIG.
Regarding the point to be provided with VE and to be saved, the contents of the register XA are transferred to the register SAVE. When scanning in the X-axis direction, the process of (XA) + (XC) → (XA) is performed. Further, when moving in the Y-axis direction in step (4), the process of (YA) + (YC) → (XA) is performed.

As a further modification, it is possible to draw an anti-aliased straight line having a width. As shown in FIG. 10, two side lines 231 and 232 of a straight line having a width are
It suffices to correspond to one side DDA. Further, both ends of the straight line can be cut by the bounding box 233.

Next, FIG. 11 shows a block diagram of an image processing apparatus according to the second embodiment of the present invention. In this embodiment, the present invention is applied to a shading process for a polygon of a three-dimensional graphic.

In the figure, the image processing apparatus of this embodiment has an area DDA1, an address generator 9, an inclination register 3, a table ROM 5, a selector 7, a color DDA 51, Z.
It is composed of a DDA 53 and a pixel calculator 55.

The detailed configurations and operations of the area DDA1, the address generator 9, the inclination register 3, the table ROM 5, and the selector 7 are the same as those in the first embodiment,
The difference is that the output of the selector 7 is used not as the gradation itself but as an interpolation coefficient α for α blending.

The color (R, G, B) interpolation and the Z value interpolation are performed by the following primary interpolation as in the case of the sides DDA 11, 12, and 13.

F (x, y) = a × x + b × y + c (7) The color DDA 51 has three DDAs, as shown in FIG.
That is, R / DDA51r, G / DDA51g, and B / D
It consists of DA51b. R, DDA51r, G,
DDA 51g, B / DDA 51b, and ZDDA
53 has the configuration shown in FIG. This is the area DDA
The configuration is almost the same as that of the sides DDA 11, 12, and 13 in 1, but the output SDj (j = r, g, b) or Z
i simply takes out the integer part int of the register XA.

The pixel calculator 55 performs Z-check and α-blending for anti-aliasing.
The color value SD from the color DDA 51, the Z value Zi from the ZDDA 53, the color value DDm and the Z value Zm read from a buffer memory (not shown), the area determination signal R from the area DDA1, and the interpolation coefficient α are input. , Write data WDm and a write enable signal WE for an image memory (not shown).

FIG. 14 shows a detailed configuration diagram of the pixel calculation section 55. As shown in FIG.
Α blending calculator 7 corresponding to R, G, and B colors
1, 72, and 73, a color input register 76, a color output register 77, a Z output register 78, a Z input register 79,
Write enable delay register 80 and Z comparator 7
It is composed of 5.

The color value DD read from the buffer memory via the color input register 76 and the color value (drawing data) SD from the color DDA 51 are decomposed into R, G and B (DDr, DDg, DDb, And SDr, SDg,
SDb) three α blending computing units 71, 72,
And 73. α blending calculator 71,
FIG. 15 shows a detailed configuration diagram of 72 and 73. Subtractor 8
1, the multiplier 83 and the adder 85 are provided to perform the following calculation.

WDj = α × SDj + (1−α) × DDj (8) Here, j = r, g, and b, and WDj is write data to the image memory.

The Z value Zi from the ZDDA 53 is compared with the Z value Zm read from the buffer memory via the Z input register 79 by the Z comparator 75, and when the data to be written is in front (the Z value is small). , The comparison result Co is “1”
Then, the gate circuit G11 obtains a logical product with the area determination signal R indicating that it is inside the polygon or near the side, and generates the write enable signal WE. However, in order to match the timing with the write data, it is output via the write enable delay register 80.

[0078]

As described above, according to the present invention, the linear means of the two-dimensional coordinate system is sequentially calculated by the calculating means in correspondence with each side of the polygon, and the drawing point is relative to the polygon. The positional relationship is determined, the displacement of each drawing point from the side of the polygon is determined, and the color or gradation of the drawing point near the side of the polygon is changed by the conversion means based on this displacement, and the bitmap is set. Since the inside of the polygon is filled or shaded on the memory, the displacement calculation process for anti-aliasing and the determination process of the polygon internal region in the filling process, which are conventionally independent processes, are performed. It is possible to provide an image processing device capable of drawing a polygon subjected to antialiasing at high speed with a smaller amount of hardware.

Further, according to the present invention, the linear means of the two-dimensional coordinate system is sequentially calculated by the calculating means in correspondence with both sides of the straight line having a width, and the sides of the drawing point on both sides of the straight line are calculated. Relative to the drawing line, the displacement of each drawing point from both sides of the straight line is obtained, and based on this displacement, the color or gradation of the drawing points near the two sides of the straight line is converted by the converting means. Since it was decided to draw an anti-aliased straight line, it is possible to commonly perform the displacement calculation process for anti-aliasing and the internal region determination process of a straight line having a width in filling, which is less. It is possible to provide an image processing apparatus capable of drawing a straight line subjected to anti-aliasing processing at high speed with the amount of hardware.

Further, according to the present invention, the calculating means sequentially calculates the linear expression of the two-dimensional coordinate system corresponding to each side of the polygon, and determines the relative positional relationship of the drawing point with respect to the polygon. Further, the displacement of each drawing point from the side of the polygon is obtained, and the value to be written in the bitmap memory by the ratio determining means and the value already written in the address should be mixed based on this displacement. Since the ratio is determined and the inside of the polygon is filled or shaded on the bitmap memory, the above-described image processing apparatus can be applied to the polygon shading process of a three-dimensional graphic. It will be possible.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an image processing apparatus according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the present invention, and is a diagram illustrating a distance in the Y-axis direction to a side of a polygon.

FIG. 3 is a detailed configuration diagram of an area DDA in the image processing apparatus according to the first embodiment.

FIG. 4 is a side D in the image processing apparatus according to the first embodiment.
It is a detailed block diagram of DA.

FIG. 5 is a logic circuit diagram of an output value generation circuit in the side DDA of the image processing apparatus of the first embodiment.

FIG. 6 is an explanatory diagram of address generation of an address generation unit in the image processing apparatus according to the first exemplary embodiment.

FIG. 7 is an explanatory diagram of a scanning method in a modified example of the image processing apparatus of the first embodiment.

FIG. 8 is an explanatory diagram of a scan method in a modified example of the image processing apparatus of the first embodiment.

FIG. 9 is a detailed configuration diagram of a side DDA in a modified example of the image processing apparatus of the first embodiment.

FIG. 10 is a diagram illustrating drawing of a straight line having a width in another modification of the image processing apparatus of the first embodiment.

FIG. 11 is a configuration diagram of an image processing apparatus according to a second embodiment of the present invention.

FIG. 12 is a configuration diagram of a color DDA in the image processing apparatus according to the second embodiment of the present invention.

FIG. 13 is a detailed configuration diagram of colors DDA and ZDDA in the image processing apparatus according to the second embodiment of the present invention.

FIG. 14 is a detailed configuration diagram of a pixel calculator in the image processing apparatus according to the second embodiment of the present invention.

FIG. 15 is a detailed configuration diagram of an α blending computing unit in the pixel computing unit of the image processing apparatus according to the second embodiment of the present invention.

FIG. 16 is an explanatory diagram of aliasing of sides of a polygon.

FIG. 17 is an explanatory diagram of sides of an anti-aliased polygon.

FIG. 18 is an explanatory diagram of antialiasing according to a conventional technique.

FIG. 19 is an explanatory diagram of a spatial filter in anti-aliasing according to a conventional technique.

FIG. 20 is an explanatory diagram of a polygon scanning method according to a conventional technique.

[Explanation of symbols]

1 Area DDA (Calculation Means) 3 Gradient Register 5 Table ROM (Conversion Means) 7 Selector 9 Address Generation Unit DBUS Data Bus ADR Address XYSEL Signal that indicates the direction of change of address is X-axis direction or Y-axis direction ESEL Side selection signal VAL Displacement signal GRD Side slope value C Gradation value P, R Area determination signal WDm Write data WE write enable signal 11, 12, 13 Side DDA 15 Priority encoder 17 Selector 19 Area determination circuit P0, P1, P2 Signals Q0, Q1, Q2 indicating that it is near an edge Signals V0, V1, V2 indicating that the drawing point is inside the triangle with respect to that edge V0, V1, V2 Decimal number including the sign of the value of f (x, y) Part YA, XA, YC, XC, SAVE register 21, 22, 61, 62 Selector 23, 3 Adder 25 Output value generation circuit sign Sign bit dec Fractional part int Integer part Output of XAo register XA G1 to G4, G11 Gate circuit 203 Polygon 205, 213, 223 Rectangular area 211, 221 Triangle P1, P2, P3, P1y , P2y, P3y Points 231 and 232 Straight lines 233 Bounding box 51 Color DDA 53 ZDDA 55 Pixel calculation part α Interpolation coefficient 51r R / DDA 51g G / DDA 51b B / DDA SD, SDj, SDr, SDg, SDb Color DDA Color value from Zi Z value from ZDDA DD, DDm Color value read from buffer memory Zm Z value read from buffer memory 71, 72, 73 α blending calculator 76 Color input register 77 Color output register 78 Z output register 7 Z input register 80 write enable delay register 75 Z comparator WD, the write data Co comparison results to WDj image memory

Claims (8)

[Claims] 1. A linear expression of a two-dimensional coordinate system is sequentially calculated corresponding to each side of a polygon, and a relative positional relationship of a drawing point with respect to the polygon is determined, and a polygonal position of each drawing point of the polygon is determined. And a conversion unit for changing the color or gradation of the drawing point near the side of the polygon based on the displacement calculated by the calculation unit. An image processing apparatus, characterized in that the inside of the polygon is filled or shaded. 2. The image processing apparatus according to claim 1, wherein the conversion unit is composed of a table formed of a ROM or a RAM. 3. The image processing apparatus according to claim 1, wherein the calculation means is composed of a digital differential analyzer or a linear interpolation circuit. 4. The calculation means defines a rectangular area including the polygon or overlapping the polygon, and scans in two directions in a two-dimensional coordinate system only inside the rectangular area. The image processing apparatus according to claim 1, 2, or 3. 5. The calculation means defines a rectangular area including the polygon or overlapping the polygon, and scanning in two directions in a two-dimensional coordinate system is performed within the rectangular area and only inside the polygon. The method according to claim 1,
2. The image processing device according to 2 or 3. 6. A linear expression of a two-dimensional coordinate system is sequentially calculated corresponding to both sides of a straight line having a width, and a relative positional relationship of drawing points with respect to both sides of the straight line is determined. Calculating means for obtaining the displacement of the drawing point from both sides of the straight line; and converting means for changing the color or gradation of the drawing points near both sides of the straight line based on the displacement obtained by the calculating means. An image processing apparatus having an anti-aliased straight line. 7. The image processing apparatus according to claim 6, wherein the calculation means defines an arbitrary rectangular area, and scans in two directions in a two-dimensional coordinate system inside the rectangular area. 8. A linear expression of a two-dimensional coordinate system is sequentially calculated corresponding to each side of the polygon, and a relative positional relationship of the drawing point with respect to the polygon is determined, and the polygon of each drawing point is calculated. Calculating means for obtaining a displacement from a side, and a ratio determining for determining a ratio at which a value to be written in the bit map memory and a value already written in the address should be mixed based on the displacement obtained by the calculating means. And an image processing device for filling or shading the inside of the polygon on a bitmap memory.