JPH05298460A - Device for expressing shell quality sense - Google Patents

Abstract

PURPOSE:To easily express the sense of shell quality or CD quality on an objet surface in three-dimensional computer graphic production. CONSTITUTION:A shape input device 10 inputs a shell shape, an information designating device 12 designates information of the position of the inputted object, a light, a camera and a virtual cube which is used in environment mapping, a painting device 14 generates a mosaic pattern picture consisting of such color as red, green, blue yellow, black, etc., as the picture for environment mapping and a picture generating device 16 generates a bump mapping picture, executes bump mapping on the inputted object surface and permits the picture for environment mapping which is generated in the painting device 14 to be photographed so that a twodimensional projection picture generating device 18 generates the twodimensional picture and the picture is stored in a frame memory 20.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a three-dimensional computer
The present invention relates to a shell texture expressing device capable of expressing a shell-like texture on an object surface by image creation using graphics (CG).

[0002]

2. Description of the Related Art Computer graphics (C
G), eg CG calendar, CG animation, C
When producing G commercials, CG posters, high-definition CG, etc., conventional techniques for expressing the surface of an object having the texture of a shell are not clear. However, let's express the phenomenon that appears as a peculiar radial pattern on the surface of the knobs of the stereo, the handle of the door, etc., or the surface when the record board is viewed from a distance using a model modified from Blinn's lighting model. The technique described above has been proposed by Takagi in "Study on anisotropic reflection model" (Information Processing Society of Japan Graphics and CAD Study Group (1-1 (1983))).

The lighting model used by Takagi is intended to express a texture by giving anisotropy to the minute surface distribution function of the above Blinn model.

[0004]

However, depending on the model of Takagi, anisotropic highlights can be obtained, but since the spectral effect is not taken into consideration, the iridescent color (spectral color) peculiar to shells is obtained. However, there was a problem that the texture of the shell could not be expressed sufficiently.

Further, when the above model is used, there is also a problem that calculation takes a long time.

The present invention has been made to solve the above-mentioned conventional problems, and can easily express a shell-like texture such as a shell or CD on the surface of an object in the production of three-dimensional computer graphics. An object of the present invention is to provide a shell texture expression device capable of performing the same.

[0007]

SUMMARY OF THE INVENTION The present invention is a shell texture expressing device for expressing a shell-like texture on an object surface when producing three-dimensional computer graphics, wherein an image of a plurality of colors is displayed on the object surface. The above-mentioned problem is achieved by adopting a configuration having a function of performing environment mapping using the same and performing strong bump mapping on the object surface to calculate the brightness of the object surface.

[0008]

According to the present invention, the environment mapping and the bump mapping are simultaneously applied to the same surface of the object, and the environment mapping images are red (R), green (G), blue (B),
By using an image in which a plurality of colors such as cyan (C), magenta (M), and yellow (Y) are combined in a mosaic pattern, for example, a spectral effect is given, and bump mapping is strongly set to change the normal vector. An anisotropic reflection effect is provided by increasing By doing so, it is possible to simultaneously give a spectral effect and an anisotropic reflection effect to the object surface, and it is possible to express a shell-like texture on the object surface.

Further, by designating a large value for the specular reflection component when designating the ground color for the object surface, it is possible to efficiently express a shell-like texture.

The features of the present invention will be described in more detail.

In ordinary computer graphics, a landscape is used as an image to be reflected (environment mapping image) when performing environment mapping, whereas in the present invention, a plurality of scenes are used to express the spectral effect. An image composed of a pattern in which the colors are combined in a mosaic pattern is used.

Further, in the normal bump mapping, the process of virtually bending the direction of the surface is performed, but in the present invention, the degree of bending of the surface is strong, for example, by setting it twice or more of the normal, abnormal Shaped highlights (usually round)
I am trying to express.

At this time, if the bump mapping is set strongly, the direction of the normal vector of the surface is greatly inclined at each minute surface, and the portion with less specular reflection becomes large. It is effective to set it to twice or more.

By performing bump mapping as described above, it is possible to generate a highlight in a distorted shape that is similar to the mapping pattern. Then, by combining the distorted highlight (anisotropic reflection) and the spectral color by the environment mapping, the texture of the shell and the C
It is possible to express a shell-like texture such as D texture.

Furthermore, by increasing the value of the specular reflection component when the ground color is designated for the object surface, it is possible to greatly improve the effect of expressing a shell-like texture.

Therefore, according to the present invention, the shell-like texture can be easily expressed by applying the environment mapping and the bump mapping to the same object surface under appropriate conditions.

Further, it is possible to change the spectral effect by changing the color information or the combination pattern thereof as the image mapping, and also change the anisotropic reflection effect by changing the bumping map image. Since it is possible, the shell-like texture can be variously changed and adjusted over a wide range.

Further, since the shell-like texture can be expressed on the object surface only by using the environment mapping and the bump mapping together, it is possible to significantly reduce the calculation speed.

[0019]

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

FIG. 1 is a block diagram showing a main part of a shell texture expressing device according to the first embodiment of the present invention.

The shell texture expressing device specifies a shape input device 10 for inputting a dish-shaped object shape representing the shell body, and information about the position of the object shape input by the shape input device 10, lights, cameras, and the like. An information designating device 12 for creating an environment mapping image creating paint device 14 for creating an environment mapping image reflected on the surface of an object,
Bump mapping image production apparatus 1 for producing a bump mapping image for imparting an uneven shape to an object surface
6 and 2 for creating a two-dimensional projection image based on the information input from the information designating device 12 and the images created by the environment mapping image creating paint device 14 and the bump mapping image creating device 16, respectively. Three-dimensional projection image creating apparatus 18 and the two-dimensional projection image creating apparatus 1
Frame memory 2 for recording the image created in 8.
It has 0 and.

The shape input device 10 is a device for inputting an object shape, and in this embodiment, the shape of the shell can be represented as a collection of surface information, that is, as a set of surfaces such as a large number of triangles or quadrangles. It is like this. that time,
Each surface is represented by a collection of vertex information (x, y, z coordinates).

The shape can be input from a keyboard or a mouse using a modeler, or can be generated by a computer.

When the shape is input by the shape input device 10, the position where the bump mapping image is pasted on the surface, the strength of the bump mapping, the ground color of the object surface, and the like are also specified at this stage.

As shown in FIG. 2, the designation of the sticking position on the surface of the bump mapping image is performed by the bump mapping image 2 represented by uv coordinates composed of 512 pixels × 512 pixels.
The coordinates (u ₁ , v ₁ ) to (u ₄ , v ₄ ) of 2 are the vertex coordinates (x ₁ , y ₁ , z ₁ ) to (x ₄ , y) of the surface data 24.
₄ and z ₄ ).

The intensity of the bump mapping will be described at the same time as the step of explaining the two-dimensional projection image creating apparatus 18 later.

When the ground color of the object surface is designated, a larger value is designated for the specular reflection component than for the environment reflection component and diffuse reflection component. An example of the parameters used in this color designation is shown below (usually, most of the parameters are designated as specular reflection components).

Environmental reflection of surface (Da): R (0.1), G (0.1),
Diffuse reflection (Kd) of B (0.1) plane: R (0.1), G (0.1),
B (0.1) plane specular reflection (Ks): R (1.0), G (1.0),
B (1.0) Specular reflection coefficient (Exp): 30.0 Reflection coefficient (Ref): 0.5

Next, the information designating device 12 for designating information such as object position, light, camera, environment mapping, etc. will be described.

In the information specifying device 12, the position of the object shape input by the shape input device 10, light information (position, direction, color, intensity), camera information (position, direction,
Specify information such as angle of view, aspect ratio, and virtual cube used for environment mapping.

A state in which each information is designated by the information designating device 12 is conceptually shown in FIG.

When designating the above information, the ambient light is set low and the light intensity is set strong as shown below (actual brightness is the product of the color and intensity of the light information below). Given).

Ambient light: R (0.1), G (0.1), B (0.1) Light information Type: Point light source Position: x 1, y 1, z 1 Color: R (0.7) , G (0.7), B (0.7) Strength: 3.0 (usually 1.0)

The environment mapping image creating / painting device 14 is a device for interactively creating an image for environment mapping, and as shown in FIG. The environment mapping image (512 pixels × 512 pixels in the figure) can be created.

The environment mapping image shown in FIG. 4 has a mosaic pattern of a plurality of colors.

The bump mapping image production device 16
Is a device for generating the bump mapping image shown in FIG. 5 by software, and this bump mapping image is composed of a monochrome image (8 bits) of 256 gradations having many black and white areas.

The two-dimensional projection image creating device 18 maps the bump mapping image on each surface of the object based on the pasting coordinates (u, v) input by the shape input device 10, and the method of the result of the bump mapping is mapped. The environment mapping image is mapped based on the line vector, and the viewpoint, the gazing point (corresponding to the focus of the camera), and the light source are placed at the predetermined coordinate positions, and the brightness of the minute part of each surface is calculated, This is a device for generating a shaded two-dimensional image as shown in FIG. 6 by performing hidden surface deletion processing for deleting an invisible surface.

The two-dimensional image shown in FIG. 6 shows a target shell in a size of 1024 × 1024 (R, G, B), and the surface of the shell 32 is blue or red for each minute area. , Green, yellow, etc., and a highlight 34 of a distorted shape is formed on a part of it.
The image shows the seashell as a whole.

Next, (1) bump mapping and (2)
The details of the environment mapping process will be described in detail.

(1) In bump mapping, the bump coordinates of the bump mapping image created by the image production device 16 are used as the pasting coordinates (u, v) input by the shape input device 10.
Is a process of mapping to each surface constituting the object surface in accordance with. The flow of this processing is shown below.

Data obtained by differentiating the bump mapping image (8 bits) created by the image producing device 16 using the following differential equations (1) and (2) with respect to each direction of u and v. Create (one for each direction u and v).

Du _nm = (P _{(n + 1) m} −P _nm ) / 255/2 (1) Dv _nm = (P _{n (m + 1)} −P _nm ) / 255/2 (2) where P _nm : coordinates in the bump mapping image u = n, v =
Pixel value of m: Du _nm : The result of differentiating in the u direction (difference between P _{(n + 1) m} and P _nm ) In the case of m = 0, the same value as m = 1 is put in Du _nm . In the case of m = 511, the same value as m = 510 is put in Du _nm . Dv _nm : Result of differentiation in the v direction (difference between P _{n (m + 1)} and P _nm ) When n = 0, Dv _nm is set to the same value as n = 1. In the case of n = 511, the same value as n = 510 is put in Dv _nm .

Du and D which are the results calculated as described above
The direction of the ray vector of the surface is corrected by the following equation (3) based on the data of v. In the equation (3), * represents multiplication, and x represents vector cross product.

[0044]

[Equation 1]

FIG. 7 shows the mutual relation of the vectors included in the above equation (3).

(2) As for the environment mapping, as conceptually shown in FIG. 8, it is assumed that an image for environment mapping is attached to each surface of the virtual cube designated by the information designating device 12,
It is a process of reflecting the image on an object plane installed in the virtual cube. The data used for this reflection is calculated based on the normal vector corrected by bump mapping.

Next, the calculation formula of the lighting model used in this embodiment will be shown. This is based on the Phong model, and the model formula is illustrated in FIG. In the formula, represents the inner product.

[0048]

[Equation 2]

As described above in detail, according to the present embodiment, 3
In three-dimensional CG image production, the texture of a shell can be easily added to an object, and the calculation time required for the calculation can be short, so that the cost can be reduced. Moreover, by preparing a plurality of textures for environment mapping and textures for bump mapping, it is possible to easily produce an object image having a texture of a shell (pearl, screw).

Next, a second embodiment according to the present invention will be described.

In this embodiment, for a disk-shaped object surface,
In the case of substantially the first embodiment except that the image of the intersecting iridescent pattern as shown in FIG. 10 is used as the environment mapping image and the image of the concentric circle pattern as shown in FIG. 11 is used as the bump mapping image. The same processing as is performed.

According to this embodiment, it is possible to easily produce an object image having a CD (compact disc) texture.

The present invention has been specifically described above, but the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the invention.

For example, the method of creating the environment mapping image is not limited to the case of using the image creating paint device 14, and (1) red, green, and
Image data having a shell-specific color such as blue, cyan, magenta, and yellow can be generated, and the image can be used as an environment mapping image. Further, (2) it is possible to capture a film on which an actual shell is reflected as a digital image with a scanner and use the image as an environment mapping image. Further, (3) the image created in (1) or (2) above may be modified by the environment mapping image creating / painting device 14 of the above embodiment to be used as the environment mapping image.

In order to create the bump mapping image, a monochrome image having a large number of black and white areas is created using a paint device without using software as described above, and the film is captured by a scanner as a digital image. The image can also be used as a bump mapping image.

Further, when the environment mapping is performed, the virtual cube is used in the above-mentioned embodiment, but the present invention is not limited to this, and it is also possible to perform the environment mapping using a virtual sphere.

[0057]

As described above, according to the present invention, 3
It is possible to easily express a shell-like texture such as a shell texture or a CD texture on the surface of an object by producing a three-dimensional computer graphics.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a shell texture expressing device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation of pasting a bump mapping image onto a surface.

FIG. 3 is an explanatory diagram showing a virtual cube used for environment mapping.

FIG. 4 is an explanatory diagram showing a method of creating an environment mapping image.

FIG. 5 is an explanatory diagram showing an image for bump mapping.

FIG. 6 is an explanatory view conceptually showing the completed shell.

FIG. 7 is an explanatory diagram showing the mutual relationship of vectors in bump mapping.

FIG. 8 is an explanatory diagram showing environment mapping processing.

FIG. 9 is an explanatory diagram of a lighting model.

FIG. 10 is an explanatory diagram showing an environment mapping image applied to the second embodiment according to the present invention.

FIG. 11 is an explanatory diagram showing a bump mapping image applied to the embodiment.

[Explanation of symbols]

 10 ... Shape input device, 12 ... Information designating device, 14 ... Environment mapping image creation paint device, 16 ... Bump mapping image creation device, 18 ... Two-dimensional projection image creation device, 20 ... Frame memory, 22 ... Bumping map image, 24 ... Surface data, 26 ... Display, 28 ... Mouse, 30 ... Environment mapping image, 32 ... Seashell, 34 ... Highlight.

Claims (1)

[Claims] 1. A shell texture expressing device for expressing a shell-like texture on an object surface when producing three-dimensional computer graphics, wherein environment mapping is performed on the object surface using images of a plurality of colors. A shell texture expressing device having a function of performing strong bump mapping on the object surface to calculate the brightness of the object surface.