JPH09231381A - Drawing equipment - Google Patents

Abstract

(57) An object of the present invention is to provide a drawing device that draws shape data in an image generated using a computer in a frame buffer at high speed with a texture and a natural taste close to reality. A data storage unit 101 stores shape data including polygons and line segments generated by computer graphics. The function storage unit 102 stores a piecewise linear function including a plurality of sections. Deformation means 1
03 deforms the shape data stored in the data storage means 101 by the piecewise linear function stored in the function storage means 102 to generate deformation data. The modification data storage unit 104 stores the modification data obtained by the modification unit 103. The drawing unit 105 draws the deformation data stored in the deformation data storage unit 104 on the frame memory 300.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing device used for a computer graphics system which is a video device using a computer, a special effect device, a video game machine and the like.

[0002]

2. Description of the Related Art For example, in a home TV game machine, a personal computer, a computer graphics system, or the like, the image is output to a television receiver, a monitor receiver, a cathode ray tube (CRT) display device, or the like for display. In an image generation device that generates image data, that is, display output image data, a central processing unit (CPU) is used.
By providing a dedicated drawing device between the frame buffer and the frame buffer, high-speed processing is possible.

That is, in the above image generating apparatus, C
On the PU side, when generating an image, instead of directly accessing the frame buffer, geometry processing such as coordinate conversion, clipping, and light source calculation is performed, and polygons (polygons) such as a triangle and a quadrangle and line segments are generated. A three-dimensional shape is defined as a combination of (lines), a drawing command for drawing a three-dimensional image is created, and the drawing command is sent to the drawing device.

For example, when displaying a three-dimensional shape, C
The PU transfers drawing commands corresponding to a plurality of polygons and lines obtained by decomposing a three-dimensional shape to the drawing device. Then, the drawing device interprets the drawing command sent from the CPU, considers the colors and Z values of all the pixels that form the polygon from the color data of the vertices and the Z value indicating the depth, and then the pixel data. Is written to the frame buffer and rendering is performed to draw a figure in the frame buffer.

The Z value is information indicating the distance in the depth direction from the viewpoint.

By the way, the shape of the display output image data generated by the image generating apparatus as described above is characterized by a solid contour line and a monotonous color. For this reason,
By giving brightness and color to the above shapes, we pursue realistic lettering to give a more realistic texture and natural taste, and to improve the physical phenomena by improving the lighting model and mapping technology. Various studies have been conducted to capture it with relative fidelity.

For example, in the above-mentioned image generating apparatus, when the drawing command corresponding to each polygon and line obtained from the three-dimensional shape as described above is transferred from the CPU to the drawing apparatus, the three-dimensional shape is further improved. Techniques called texture mapping and mip mapping have been adopted in order to make a close representation. Further, in the above-mentioned image generation device, a method of changing the display color by converting the color data of the image through a color look-up table (CLUT: Cclor Lock Up Table) storing the color conversion data is also widely known. There is.

Here, the texture mapping is a technique in which a two-dimensional image (design) prepared separately as a texture source image, that is, a texture pattern, is attached to the surface of polygons constituting an object. In addition, mip mapping is one of texture mapping methods that interpolates pixel data so that a pattern attached to a polygon does not become unnatural when it approaches or moves away from a three-dimensional shape. .

On the other hand, since the non-photorealistic lettering session was first established in "SIGGRAPH '90", "Paint By Numbers: Abstra" in "Paul Haeberli"
ct Image Representations ”(SIGGRAPH'90)” oil painting style expression, “Georges Winkenbachi” and “David H.
Sales in ”“ Computer-Generated Pen-and-Ink Illu
Research on non-photorealistic lettering, such as the expression of "stration"(SIGGRAPH'90)", is also being conducted.

[0010]

However, in the image generating apparatus as described above, in order to draw the shape data of an image having a texture or a natural taste close to reality in the frame buffer, the image is analyzed. Although it is necessary to provide a calculation circuit for conversion in the drawing device, the calculation circuit is expensive. Therefore, the conventional drawing apparatus cannot reduce the cost of the apparatus.

Further, in order to draw the shape data of an image having a texture and a natural taste close to reality in the frame buffer at high speed, it is necessary to provide special drawing hardware in the drawing device. Therefore, the conventional drawing device
Even if the processing speed is high, without special hardware, it was not possible to draw the shape data of an image having a texture and a natural taste close to reality in the frame buffer at high speed.

Therefore, the present invention has been made in view of the conventional circumstances as described above, and has the following objects.

That is, an object of the present invention is to provide a drawing apparatus for drawing shape data in an image generated by using a computer in a frame buffer at high speed with a texture and a natural taste close to reality. .

A further object of the present invention is to provide a drawing apparatus that can inexpensively realize high speed drawing of shape data in an image generated by using a computer with a texture and a natural taste close to reality. To provide.

Another object of the present invention is to provide a general-purpose drawing device that draws shape data in an image generated by using a computer into a frame buffer at high speed with a texture and a natural taste close to reality. To provide.

[0016]

In order to solve the above-mentioned problems, a drawing apparatus according to the present invention is a drawing apparatus for drawing shape data consisting of polygons and line segments generated by computer graphics on a frame memory. And
Data storage means for storing the shape data, function storage means for storing a piecewise linear function consisting of a plurality of sections,
Deformation means for deforming the shape data stored in the data storage means by the piecewise linear function stored in the function storage means to generate deformation data, and deformation data for storing the deformation data obtained by the deformation means. It is characterized by comprising a storage means and a drawing means for drawing the deformation data stored in the deformation data storage means on a frame memory.

In the drawing apparatus according to the present invention, the shape data generated by the computer graphic is
It is characterized by being two-dimensional shape data.

In the drawing apparatus according to the present invention, the shape data generated by the computer graphic is
It is characterized by being three-dimensional shape data.

Further, the drawing apparatus according to the present invention is characterized in that the function storage means stores a three-dimensional piecewise linear function.

Further, the drawing apparatus according to the present invention is characterized in that the function storage means stores a two-dimensional piecewise linear function.

Further, in the drawing apparatus according to the present invention, the function storage means stores a plurality of types of piecewise linear functions having different numbers of sections. Then, the deforming means, for each side and line segment of the polygon of the target shape data, according to the side and line segment of the polygon from a plurality of kinds of piecewise linear functions stored in the function storage means. It is characterized in that deformation data is generated by using an arbitrary piecewise linear function selected.

[0022]

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

The drawing apparatus according to the present invention is, for example, in an image generating apparatus of a computer graphics system,
As shown in FIG. 1, the CPU 200 and the frame buffer 3
It is applied to the drawing apparatus 100 provided between the two.

First, the image generation device is a device for generating display output image data. For example, when displaying and outputting a three-dimensional shape, the CPU 200 defines a three-dimensional shape as a combination of polygons and lines. A drawing command corresponding to each of a plurality of polygons and lines obtained by decomposing a three-dimensional shape is transferred to the drawing device 100.

Therefore, as shown in FIG. 1, the drawing apparatus 100 includes a shape data memory 101 for storing the output of the CPU, a change information memory 102 for storing a piecewise linear function, and a shape data memory. Deformation processing circuit 10 to which respective outputs of 101 and change information memory 102 are supplied
3, a transformation data memory 104 for storing the output of the transformation processing circuit 103, and a drawing processing circuit 105 to which the output of the transformation data memory 104 is supplied.

Next, a series of operations of the drawing apparatus 100 configured as described above will be described.

First, the shape data memory 101 stores the CP
A drawing command from the U200, that is, three-dimensional shape data (hereinafter, simply referred to as shape data) composed of a combination of polygons and lines is stored.

On the other hand, in the change information memory 102, for example, as shown in FIG. 2, three sections "S" in which the length direction is represented by the u-axis and the deformation direction is represented by the v-axis and the w-axis are shown. ₃₀ =
(U0, v0, w0) ~S 3 1 = (u1, v1, w
1) ”,“ S ₃ 1 = (u1, v1, w1) to S ₃ 2 = (u
2, v2, w2) "," _{S 3 2 = (u2, v2} , w2)
˜S ₃ 3 = (u3, v3, w3) ”is stored in advance as a three-dimensional piecewise linear function f ₃ .

Next, the transformation processing circuit 103 transforms the shape data stored in the shape data memory 101 using the three-dimensional piecewise linear function f ₃ stored in the change information memory 102. Perform processing. Then, the modification processing circuit 103 stores the modified shape data obtained by the above modification processing in the modification data memory 104.

A detailed description of the transformation process performed by the transformation processing circuit 103 will be given later.

Next, the drawing processing circuit 105 reads the deformed shape data stored in the deformed data memory 104, and sets all the pixel data forming the polygons and lines in the read deformed shape data in the three-dimensional space. In consideration of the brightness of the pixel and the value of the Z coordinate, the frame buffer 3
Draw to 00. Further, the drawing processing circuit 105 performs texture mapping processing and mip mapping processing on the deformed shape data read from the deformation data memory 104, and the deformed shape data subjected to the texture mapping processing and mip mapping processing is used as the frame buffer 30.
Draw to 0.

The drawing processing performed by the drawing device 105 will be described below. For example, the frame buffer 300
(Not shown) includes a frame buffer that stores the brightness of each pixel in the three-dimensional space and a Z buffer that stores the value of the Z coordinate (Z value) of a visible pixel in the three-dimensional space. Therefore, the drawing processing circuit 103 causes the brightness or Z value of a pixel (hereinafter, referred to as a new pixel) newly written in the frame buffer, and a pixel (hereinafter, referred to as a pixel corresponding to the new pixel stored in the Z buffer). It is determined whether or not the new pixel is in front of the old pixel by comparing the Z value of the old pixel). Then, the drawing processing circuit 103 writes the new pixel in the frame buffer and updates the Z value stored in the Z buffer only when the new pixel is before the old pixel.

The drawing process performed by the drawing device 105 as described above is described in "Z Buffer Algorithm" of "Practical Computer Graphics" (Nikkan Kogyo Shimbun). Detailed description is omitted.

As described above, the drawing processing circuit 103 draws the deformed shape data stored in the deformation data memory 104 in the frame buffer 300.

The deformed shape data drawn in the frame buffer 300 is supplied as a video signal to a television receiver, a monitor receiver or the like (not shown) for display and output.

Next, the deformation process performed by the above-described deformation processing circuit 103 will be specifically described.

For example, in a three-dimensional space represented by xyz coordinates, a point P (= (xp, yp,
zp)) and the point Q (= (xq, yq, zq)) will be described for the case where the deformation process is performed on the shape data of the line L.

First, assuming that the direction from the point P to the point Q of the line L is the u axis, unit vectors of the u axis, the v axis, and the w axis are expressed as follows: u = UV (SV (Q, P)) v = CP (X, u) w = CP (u, v).

In the above equation, "x" is the unit vector of the x axis in the xyz coordinate system, "U".
V () ”is a unit vector calculation,“ SV () ”is a vector subtraction, and“ CP () ”is a vector cross product.

Next, the point P of the line L is made to correspond to the point "u = 0" of the three-dimensional piecewise linear function f ₃ shown in FIG. 2, and the point Q of the line L is three-dimensional piecewise. to correspond to the point of the linear function f ₃ of the "u = 1".

That is, in FIG. 2, S ₃ 0 = (u0, v0, w0) = (0,0,0) = P S ₃ 3 = (u3, v3, w3) = (1,0,0) = Q

Next, using the points S ₃ 1 and S ₃ 2 on the three-dimensional piecewise linear function f ₃ , a new point T _L3 as shown in FIG. 4 is provided between the points P and Q. 1 (= (x1, y1, z1))
And T _L32 (= (x2, y2, z2)).

That is, the point P (= (xp, yp, zp)) and the point Q (= (x
q, yq, zq)) and the length M of the line L is M = sqrt ((xq-xp) ² + (yq-yp) ² +
(Yq-yp) ² ) The calculation formula is as follows.

Then, the line L obtained by the above arithmetic expression
Length M and the point S ₃ i on the three-dimensional piecewise linear function f ₃
(= (Ui, vi, wi)) and the unit vector u (=
(Xu, yu, zu)), v (= (xv, yv, z
v)), w (= (xw, yw, zw)), and the newly generated point T _L3 i (= (xi, yi, zi)) is xi = xp + M × ui × xu + vi × xv + wi × xw yi = yp + M × ui × yu + vi × yv + wi × yw zi = zp + M × ui × zu + vi × zv + wi × zw.

Therefore, according to the above equation, the point T _L3 1
(= (X1, y1, z1)) and T _L3 2 (= (x2, y
2, z2)) is generated and the set of line segments (polyline) L as shown in FIG.
₃ {P, T _L3 1, T _L3 2, Q} is stored.

Further, for example, a point P as shown in FIG.
(= (Xp, yp, zp)), point Q (= (xq, yq,
zq)) and the point R (= (xr, yr, zr)), the deformation process is performed on the shape data of the triangular polygon G, similarly to the deformation process for the line L described above. Each of the three sides PQ, QR, and RP of G is transformed by using a three-dimensional piecewise linear function f ₃ .

As a result, a set G of vertices as shown in FIG.
₃ {P, T _G3 1, T _G3 2, Q, T _G3 3, T _G3 4, R, T
_G3 5, T _G3 6} is generated.

By the way, these points P, T _G3 1, T
_{Since G3} 2, Q, T _G3 3, T _G3 4, R, T _G3 5, and T _G3 6 do not exist on the same plane, the drawing processing circuit 103 cannot perform drawing processing in this state.

Therefore, in general, for example, as shown in FIG. 7, the center point O of the polygon G is obtained and the set G of vertices is set.
A set of triangles consisting of ₃ and the center point O {{O, P, T
_G3 1}, {O, T _G3 1, T _G3 2}, {O, T _G3 2,
Q}, {O, Q, T _G3 3}, {O, T _G3 3, T _G3 4},
{O, T _G3 4, R}, {O, R, T _G3 5}, {O, T _G3
5, T _G3 6}, {O, T _G3 6, P}} are generated and drawn using the surface normals of the respective triangles as they are.

However, as a result of drawing by using the surface normals of the respective triangles as they are as described above, as shown in FIG. 7, an image A having an uneven surface is obtained, giving a natural taste. I can't get the image I have.

Therefore, the transformation processing circuit 103 stores the set of triangles generated as described above and the surface normal of each triangle of the set of triangles in the transformation data memory 104.

Therefore, the drawing processing circuit 105 performs drawing by giving the surface normal of the original polygon G as the surface normal of all the triangles of the set of triangles stored in the deformation data memory 104. As a result, it is possible to obtain an image B having a natural taste as shown in FIG. 8 with respect to the image A shown in FIG. 7 in which only the uneven surface is drawn.

Here, for example, when the drawing processing circuit 105 performs texture mapping processing or mip mapping processing on the image B shown in FIG. 8, the texture coordinates used in the texture mapping processing or mip mapping processing are , Is calculated as follows.

For example, in the polygon G consisting of the points P, Q, and R shown in FIG. 5, the three-dimensional piecewise linear function f
The texture coordinates (m _T i, n of the point T _G3 i obtained by _3
T i) is the texture coordinates (m _T p, n _T of the points P and Q).
p) and (m _T q, n _T q) and the point S ₃ i (= (ui, vi, wi)) on the three-dimensional piecewise linear function f ₃ ,
Linear interpolation is used to obtain m _T i = (1-ui) × m _T p + ui × m _T q n _T i = (1-ui) × n _T p + ui × n _T q.

Therefore, in the drawing processing circuit 105, the texture mapping processing and the mip mapping processing are performed using the texture coordinates obtained by the above-mentioned arithmetic expression.

In the image B shown in FIG. 8, a set of triangles {{O, P, T _G3 1}, {O, T _G3 1, T _G3
2}, {O, T _G3 2, Q}, {O, Q, T _G3 3},
{O, T _G3 3, T _G3 4}, {O, T _G3 4, R}, {O,
R, T _G3 5}, {O, T _G3 5, T _G3 6}, {O, T
_G3 6, P}} does not actually exist on the plane, so when the image B is viewed from the extension of the plane of the original polygon G, it can be seen that the unevenness exists, but the three-dimensional division If the deformation using the static linear function f ₃ is too large, an image with a natural taste cannot be obtained. However, since the unevenness as described above existing in the image B shown in FIG. 8 is not so large, it does not cause a problem from a normal viewpoint.

As described above, the drawing device 100 includes the CPU
Since the sides and lines of the polygon of the shape data supplied from the device 200 are replaced by the three-dimensional piecewise linear function f ₃ to be transformed and drawn in the frame buffer 300,
An image displayed and output by this image generation device can be an image having a natural taste.

For example, the three-dimensional shape data is the CPU 20.
When supplied from 0 to the drawing apparatus 100, as shown in FIG. 9, the image C displayed and output by the image generating apparatus has a natural taste as if the contour Eg was drawn by hand. There is. Further, when the rendering device 100 performs the above-described texture mapping processing on such a three-dimensional image C, the image displayed and output by this image generation device is more detailed as shown in FIG. The image C ^d is an image that is actually represented in the vicinity.

The transformation process performed by the drawing apparatus 100 is as follows.
Since it is a simple transformation operation using the three-dimensional piecewise linear function f ₃ , it is not necessary to provide the drawing apparatus 100 with an expensive circuit such as a calculation circuit that analyzes and transforms an image that has been conventionally used. Therefore, the drawing apparatus 100 can easily draw the shape data in the image displayed and output by the image generating apparatus with a natural taste. Further, the drawing apparatus 100 can reduce the cost of the apparatus.

Further, by performing the above-described transformation processing in the drawing apparatus 100, the three-dimensional piecewise linear function f ₃
The number of polygons of the deformed shape data obtained by deforming by the method becomes larger than the number of polygons of the original shape data. However, since the shape of the polygon of the deformed shape data is a so-called triangle fan, The vertices are shared. Therefore, the drawing apparatus 100 can draw the deformed shape data at high speed. Therefore, this image generating apparatus can display and output an image having a natural taste at high speed.

Further, similarly to the case where the original shape data is composed of polygons and lines, the deformed shape data obtained by deformation by the three-dimensional piecewise linear function f ₃ is also composed of polygons and lines. Therefore, by simply providing the transformation processing circuit 103 as described above in the conventional drawing device,
It is possible to obtain an image with a natural taste. Therefore, the drawing apparatus 100 can be generally applied to the conventional drawing apparatus.

Furthermore, in the drawing apparatus 100, the transformation processing circuit 103 is provided in the preceding stage of the drawing processing circuit 105, so that before drawing in the frame buffer 300,
Since the transformation processing is performed by the three-dimensional piecewise linear function f ₃ , for example, even when the shape data is an object like a building and the viewpoint walks inside the object (walkthrough), The transformation process by the three-dimensional piecewise linear function f ₃ is not performed again during the walkthrough. Therefore, the drawing apparatus 100 can draw the shape data having a natural taste at high speed even in an image of walking through the inside of a building.

Further, in the drawing apparatus 100 described above, the transformation processing circuit 103 performs the transformation processing by the three-dimensional piecewise linear function f ₃ , but the transformation processing circuit 103 makes the two-dimensional piecewise linear function f _3. Alternatively, the transformation process may be performed.

The case where the transformation processing circuit 103 performs the transformation processing using the two-dimensional piecewise linear function f ₃ will be described below.

First, in this case, the deformation information memory 102
, The length direction is represented by the u-axis, as shown in FIG.
The three sections “S ₂ 0 = (u
_{0, v0) ~S 2 1 =} (u1, v1) "," S ₂ 1 = (u
_{1, v1) ~S 2 2 =} (u2, v2) "," S _{2 2} = (u
_{2, v2) ~S 2 3 =} (u3, v3) "is a two-dimensional piecewise linear function f ₂ consisting of previously stored.

Therefore, for example, as shown in FIG. 3, the point P (= (xp, yp, zp)) and the point Q (= (x
When the deformation process is performed on the shape data of the line L consisting of q, yq, zq)), first, as shown in FIG. 12, a point P (= (xp, yp, zp)) and a point Q (= (X
q, yq, zq)) device coordinates P ^d (= (m
p, np)) and Q ^d (= (mq, nq)).

That is, assuming that the viewpoint is at the origin O, the line-of-sight (view) vector matches the z-axis, and the view-up vector matches the y-axis, the point (x
i, yi, zi), the width w of the screen Sc, the height h of the screen Sc, and the distance d from the viewpoint O to the screen Sc, the device coordinates (mi, ni) are set to mi = w / 2 + d. Xxi / zi ni = w / 2 + d × yi / zi.

Next, the line L ^d of points P ^d and the point Q ^d of the device coordinate system determined by the above arithmetic expression, the direction from the point P ^d of the line L ^d to point Q ^d as u axis, the unit The vector u is calculated by the arithmetic expression u = UV (SV (P ^d , point Q ^d )).

In the above equation, "UV ()"
Indicates a unit vector calculation, and “SV ()” indicates vector subtraction.

Next, the point P ^d of the line L ^d to correspond to the point "u = 0" in the two-dimensional piecewise linear function f ₂ shown in FIG. 11, the point Q ^d of the line L ^d 2 Dimensional piecewise linear function f
Correspond to the point "u = 1" of ₂ .

That is, in FIG. 11, S ₂ 0 = (u0, v0) = (0,0) = P ^d S ₂ 3 = (u3, v3) = (1,0) = Q ^d .

Next, with reference to S ₂ 1 and point S ₂ 2 points on the two-dimensional piecewise linear function f _2, new point T _L2 1 as shown in FIG. 13 (= (m1, n1) ) And T _L2 2 (= (m2
n2)) is generated.

That is, the point P ^d (= (mp, np)) and the point Q ^d (= (mq, n) are defined with the square root being “sqrt ()”.
The length M ^d of the line L ^d consisting of q)) is calculated by the arithmetic expression M ^d = sqrt ((mq-mp) ² + (nq-np) ² ).

Then, the line L obtained by the above arithmetic expression
the length M ^d of ^d, a point on a two-dimensional piecewise linear function f ₂ S ₂ i
(= (Ui, vi)) and unit vector u (= (mu,
mu)) and a new point T _G2 i to be generated is generated by an arithmetic expression mi = mp + M ^d × ui × mu-vi × mu ni = mp + M ^d × ui × nu + vi × mu.

Therefore, the point T _L2 1
(= (M1, n1)) and T _L2 2 (= (m2, n2))
1 is generated, and the modified data memory 104 stores the data in FIG.
Polyline L on the device coordinate system as shown in 3
₂ {P ^d , T _L2 1, T _L2 2, Q ^d } is stored.

Then, the drawing processing circuit 105 draws the polyline L ₂ stored in the modified data memory 104.

The drawing processing of the polyline L ₂ performed by the drawing processing circuit 105 will now be described. For example, the drawing processing circuit 105 has an optimum raster position for drawing each line of the polyline L _2. The drawing process is performed by selecting each of. In other words, the drawing processing circuit 105 always increases “n” in the device coordinate system by one unit in accordance with the inclination of the line to be drawn, and increments “m” in the device coordinate system by the actual increment. The line is determined by the distance between the line position and the closest grid position to determine the line in the frame buffer 30.
Draw to 0.

The drawing processing of the polyline L ₂ performed by the drawing processing circuit 105 as described above is described in "Practical computer graphics" (Nikkankogyo Shimbun).
esenham algorithm ”,
Here, detailed description thereof is omitted.

Further, for example, as shown in FIG.
Point P (= (xp, yp, zp)), point Q (= (xq, y
q, zq)) and the point R (= (xr, yr, zr)), the shape data of the triangular polygon G is deformed by the two-dimensional piecewise linear function f ₂ as described above. Similar to the transformation processing of the line L by the two-dimensional piecewise linear function f ₂ , the device coordinates P ^d , Q ^d , for the three vertices P, Q, R of the polygon G as shown in FIG.
Find R ^d .

Then, 3 on the device coordinate of polygon G
The two sides P ^d Q ^d , Q ^d R ^d , and R ^d P ^d are each transformed using a two-dimensional piecewise linear function f ₂ .

As a result, a set of vertices G ₂ {P ^d , T _G2 1, T _G2 2, Q ^d , T _G2 3, T as shown in FIG. 14 is obtained.
_G2 4, R ^d , T _G2 5, T _G2 6} are generated.

Therefore, in the deformation data memory 104, a set of vertices G ₂ {P ^d , T _G2 1, T _G2 2, Q ^d , T _G2.
3, T _G2 4, R ^d , T _G2 5, T _G2 6} are stored.

Then, the drawing processing circuit 105 carries out drawing processing of the set G ₂ of vertices stored in the deformation data memory 104.

The drawing processing of the vertex set G ₂ performed by the drawing processing circuit 105 will now be described. For example, the drawing processing circuit 105 uses the pixel inside the smallest quadrangle that encloses the polygon represented by the vertex set G ₂ On the other hand, the polygon filling process is performed by determining whether each pixel on the raster exists inside the polygon.

The drawing processing of the vertex set G ₂ performed by the drawing processing circuit 105 as described above is described in “Practical Computer Graphics” (Nikkan Kogyo Shimbun) “Polygon Filtering”. ,here,
Detailed description is omitted.

As described above, even if the transformation processing circuit 103 carries out the transformation processing by the two-dimensional piecewise linear function f ₂ , the transformation processing circuit 103 makes the three-dimensional piecewise linear function f.
_{As in the} case of performing the transformation process by ₃ , the drawing device 100
Can easily draw shape data with a natural taste at high speed. Further, the drawing apparatus 100 can be applied to a conventional drawing apparatus for general purposes.

In the drawing apparatus 100 described above, the piecewise linear function stored in the variable information memory 102 is a three-dimensional or two-dimensional piecewise linear function. Of the plurality of piecewise linear functions stored in the variable information memory 102 are stored for the shape data. The transformation process may be performed using a piecewise linear function corresponding to the sides of the polygons or the lengths of the lines of the shape data stored in the memory 101.

In this case, for example, the transformation processing circuit 103
Selects a piecewise linear function with a large number of sections from a plurality of piecewise linear functions stored in the shape data memory 101 when performing deformation processing on the sides or lines of a long polygon, Deformation processing is performed using the selected piecewise linear function. In addition, the deformation processing circuit 103, when performing the deformation processing on the sides or lines of a short polygon, selects a piecewise linear function having a small number of sections from among a plurality of piecewise linear functions stored in the shape data memory 101. A linear function is selected, and transformation processing is performed using the selected piecewise linear function.

As described above, when the drawing apparatus 100 deforms the sides or lines of the polygon of the shape data and draws it in the frame buffer 300, the drawing apparatus 100 uses a different piecewise linear function for each drawing to perform the modification process. By performing the above, it is possible to suppress the increase rate of the number of polygons due to the deformation processing as described above. In addition, the drawing apparatus 100 can draw shape data having an expression that the contour of the shape fluctuates.

[0090]

In the drawing apparatus according to the present invention, the data storage means stores the shape data composed of polygons and line segments generated by computer graphics. The function storage means stores a piecewise linear function composed of a plurality of sections. The deforming means deforms the shape data stored in the data storing means by the piecewise linear function stored in the function storing means to generate deformed data. The modification data storage means stores the modification data obtained by the above modification means. The drawing means draws the deformation data stored in the deformation data storage means on the frame memory. Thus, the drawing device can draw the shape data having a natural taste on the frame memory. Also,
Since the deforming means performs a simple deforming operation using the piecewise linear function stored in the function storing means, it draws an expensive circuit such as a calculation circuit for analyzing and converting an image that has been conventionally used. There is no need to install it in the device. Therefore,
The drawing device can easily draw the shape data having a natural taste on the frame memory, and the cost of the device can be reduced. Further, in the drawing device, the number of polygons of the deformed data obtained by deforming by the piecewise linear function stored in the function storage unit by performing the deforming process by the deforming unit is the number of polygons of the original shape data. Although it becomes larger, the shape of the polygon of the above deformation data is a so-called triangle fan (triangle f).
an), so many vertices are shared. Therefore, the drawing device can draw the deformation data at high speed. Further, similarly to the case where the original shape data is composed of polygons and lines, the deformation data obtained by deforming by the piecewise linear function stored in the function storage means is also composed of polygons and lines. Therefore, the shape data having a natural taste can be drawn on the frame memory only by providing the above-mentioned deforming means in the conventional drawing apparatus. Therefore, the drawing apparatus described above can be applied to a conventional drawing apparatus for general purposes. Also,
With the configuration described above, the drawing apparatus is configured to perform the transformation process using the piecewise linear function stored in the function storage unit before drawing in the frame memory. Even when the shape data is an object such as a building and the viewpoint walks inside the object (walk through), the deformation process by the piecewise linear function is not performed again during the walk through. Therefore, the drawing device can draw the shape data with a natural taste on the frame memory at high speed even for an image that walks through the interior of a building.

Further, in the drawing apparatus according to the present invention, the shape data generated by the computer graphic is two-dimensional shape data. As a result, the drawing device can easily draw the two-dimensional shape data having a natural taste on the frame memory at high speed.

Further, in the drawing apparatus according to the present invention, the shape data generated by the computer graphic is three-dimensional shape data. As a result, the drawing apparatus can draw the three-dimensional shape data having a natural taste at high speed and easily on the frame memory.

In the drawing apparatus according to the present invention, the function storage means stores a three-dimensional piecewise linear function. As a result, the deforming means can deform the shape data stored in the data storing means by a three-dimensional piecewise linear function.

Also, in the drawing apparatus according to the present invention, the function storage means stores a two-dimensional piecewise linear function. As a result, the deformation means can deform the shape data stored in the data storage means by a two-dimensional piecewise linear function.

Further, in the drawing apparatus according to the present invention, the function storage means stores a plurality of types of piecewise linear functions having different numbers of sections. Then, the deforming means, for each side and line segment of the polygon of the target shape data, according to the side and line segment of the polygon from a plurality of kinds of piecewise linear functions stored in the function storage means. The deformation data is generated using the selected piecewise linear function. As a result, the drawing apparatus can suppress the increase rate of the number of polygons due to the deformation process. Further, the drawing device can draw, on the frame memory, shape data having an expression such that the contour of the shape fluctuates.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a drawing apparatus according to the present invention.

FIG. 2 is a diagram for explaining a three-dimensional piecewise linear function consisting of three sections.

FIG. 3 is a diagram for explaining line shape data.

FIG. 4 is a diagram for explaining a transformation process for transforming the line using the three-dimensional piecewise linear function.

FIG. 5 is a diagram for explaining polygon shape data.

FIG. 6 is a diagram for explaining a deformation process for deforming the polygon using the three-dimensional piecewise linear function.

FIG. 7 is a diagram for explaining a case where drawing is performed using the surface normals of the triangles of the set of triangles obtained by the above deformation processing as they are.

FIG. 8 is a diagram for explaining a case where a surface normal of the polygon is given as a surface normal of each triangle and the drawing is performed.

FIG. 9 is a diagram for explaining an image of a cube obtained by the drawing device.

FIG. 10 is a diagram for explaining a case where a texture mapping process is performed on the cube image.

FIG. 11 is a diagram for explaining a two-dimensional piecewise linear function consisting of three sections.

FIG. 12 is a diagram for explaining a process for obtaining device coordinates of points on the line.

FIG. 13 is a diagram for explaining a line of a device coordinate system obtained by deforming the line using the two-dimensional piecewise linear function.

FIG. 14 is a diagram for explaining a polygon in a device coordinate system obtained by deforming the polygon using the two-dimensional piecewise linear function.

[Explanation of symbols]

100 drawing device, 101 shape data memory, 10
2 memory for deformation information, 103 deformation processing circuit, 104
Deformation data memory, 105 drawing processing circuit, 200
CPU, 300 frame buffer

Claims (6)

[Claims] 1. A drawing device for drawing on a frame memory shape data composed of polygons and line segments generated by computer graphics, comprising a data storage means for storing the shape data and a section composed of a plurality of sections. Storing means for storing a dynamic linear function; a deforming means for deforming the shape data stored in the data storing means by a piecewise linear function stored in the function storing means to generate deformed data; and the deforming means. A drawing device, comprising: deformation data storage means for storing the deformation data obtained in step 1; and drawing means for drawing the deformation data stored in the deformation data storage means on a frame memory. 2. The drawing apparatus according to claim 1, wherein the shape data generated by the computer graphic is two-dimensional shape data. 3. The drawing apparatus according to claim 1, wherein the shape data generated by the computer graphic is three-dimensional shape data. 4. The drawing apparatus according to claim 3, wherein the function storage means stores a three-dimensional piecewise linear function. 5. The drawing apparatus according to claim 2, wherein the function storage means stores a two-dimensional piecewise linear function. 6. The function storage means stores a plurality of types of piecewise linear functions with different numbers of sections, and the transformation means stores the function storage for each side and line segment of a target shape data polygon. The deformation data is generated by using an arbitrary piecewise linear function selected according to the sides and line segments of the polygon from a plurality of piecewise linear functions stored in the means. Drawing device.