KR20050080334A - Method of synthesizing a multitexture and recording medium thereof - Google Patents

Abstract

The present invention relates to a multi-texturing method and a recording medium recording the same, and more particularly, to a multi-texturing method for synthesizing an image used as a material texture in an environment in which graphic hardware resource limitations are used, and to efficiently use a resource. It relates to a recording medium. Multi-texturing method according to an embodiment of the present invention comprises the steps of determining the integrated map projector from the projectors of the texture maps to be synthesized; Determining an image size and a texel material of the integrated map based on the texture maps to be synthesized; And mapping the integrated map to an object through the projector of the integrated map.

Description

Method of synthesizing a multitexture and recording medium

The present invention relates to a multi-texturing method and a recording medium recording the same, and more particularly, to a multi-texturing method for synthesizing an image used as a material texture in an environment in which graphic hardware resource limitations are used, and to efficiently use a resource. It relates to a recording medium.

Texture mapping is a method of mapping a two-dimensional texture map (typically a color map) representing a material such as color or reflectivity to a three-dimensional model surface for realism of a modeled three-dimensional object surface.

Shading to make it feel like it's a lot of computation and a lot of processing time. However, by applying the texture mapping technique, the material texture of the material can be expressed more realistically with shorter processing time. Even scenes that are complex to calculate, such as reflections or complex lighting effects, can be described relatively simply using pre-applied images of reflections or lighting.

In addition, the multitexturing method, which expresses a much wider variety of textures, is now supported by hardware by applying a basic texture to a surface and then composing another texture on top of it. This means that various shading methods using hardware acceleration are enabled by allocating resources for programmable shading.

FIG. 1 shows how multitexturing is implemented in the graphics hardware consisting of three texture units. Each texture unit represented by stage0 through stage2 has information such as a texture image, filtering parameters, and the like. Inputs the texture value to express the material by and outputs the single texturing result.

At this time, since texture units composed of stage0 to stage2 are implemented in such a manner as to receive a single texturing result of texture units of the previous stage, the result of the previous texture unit is reflected in the calculation performed by the current texture unit.

On the other hand, real-time multi-texturing can be used only if graphics hardware supports it. In theory, up to 16 texture maps can be synthesized using the latest graphics hardware in real-time environment.

However, instead of using color maps alone, you can use light maps, reflection maps, environment maps, bump maps, and shadows simultaneously to express a lot of realistic effects.If you assign texture resources for shading effects, you can use one or two material images. There is a problem that can only be applied.

In addition, in a real-time environment, when processing with one-pass (single-pass) multitexturing, there is a problem in that a desired material cannot be represented because many texture maps cannot be used because of limitation of texture resources.

An object of the present invention is to provide a variety of real-time rendering effects by different effects by integrating and using a texture image to be applied to one surface of a three-dimensional object in a limited graphics resource.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, a multi-texturing method according to an embodiment of the present invention comprises the steps of determining an integrated map projector from the projectors of texture maps to be synthesized; Determining an image size and a texel material of the integrated map based on the texture maps to be synthesized; And mapping the integrated map to an object through the projector of the integrated map.

In addition, the recording medium recording the multi-texturing method according to an embodiment of the present invention is a medium on which a program for executing the method is recorded.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and those of ordinary skill in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims.

Like reference numerals refer to like elements throughout.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating a multitexturing method according to an embodiment of the present invention.

The multi-texturing method according to an embodiment of the present invention is to determine the integrated map projector from the projectors of the texture maps to be synthesized (S20) and to determine the image size and texel material of the integrated map based on the texture map to be synthesized. Step S22 and mapping the integrated map to the object through the projector of the integrated map S24.

The determining of the integrated map projector (S20) includes determining a normal vector and a center coordinate of the integrated map projector (S200) and determining a size of the integrated map projector (S202).

In the determining of the normal vector and the center coordinate of the integrated map projector (S200), the projector of the integrated map is generated through the projector information of the textures to be synthesized. The projector refers to an intermediate medium used to apply a specific material in a texture map to a specific position of a 3D object.

As an example, a method of generating a projector of an integrated map in a process of generating an integrated map by synthesizing n color maps of an object will be described.

If an integrated map is synthesized from the projectors set for n color maps, the average value is obtained by extracting the normal vector and the center coordinate of each color map projector. The average value is obtained by dividing the normal vector and the center coordinate of each projector by n.

As schematically illustrated in FIG. 3, when synthesizing an integrated map by synthesizing three individual texture maps, as described above, the average of the normal vectors and the center coordinates of the individual texture map projectors is calculated to generate the integrated map projector. .

In the step of determining the size of the integrated map projector (S202), the projector sizes of the integrated map are determined by comparing the sizes of the projectors set in the color map. In this case, since the size of the integrated map projector should be a size that can include all the projectors set in the color map, it is preferable to determine the size of the largest projector among the projectors.

Determining the image size and the texel material of the integrated map (S22) consists of determining the image size of the integrated map (S220) and determining the material of the integrated map texel (S222).

In determining the image size of the integrated map (S220), the image size of the integrated map is determined in consideration of the projector size of the determined integrated map.

In determining the size of the image of the integrated map, first, a method of determining the size of the projector of the integrated map as the integrated map image size, which may include all the used individual texture maps, and second, comparing the source images of the used individual texture maps. To determine the size of the largest source image as the size of the integrated map. Third, calculate the size ratio of the projectors of the integrated map and the projectors of the individual texture maps to calculate the largest ratio value and the largest of the source images of the individual texture maps. A method of multiplying the size value of the source image and determining that value as the image size of the unified map can be used.

Since the third method has a larger integrated map image size than the first and second methods, it takes a long time to perform an integrated map image, but has an advantage of improving image quality.

4 is a view for explaining a method of determining the size of the integrated map image according to an embodiment of the present invention.

As shown in FIG. 4, the projector size of the integrated map is 100, the projector sizes of each individual texture map are 30, 50, and 40, and the original image size of each individual texture map is 300, 160, 150. In this case, when the third method described above is used as a method of determining the image size of the integrated map, the image size of the integrated map is determined as the maximum size x maximum ratio value of the original source image.

The maximum size of the original image is 300, and the maximum ratio is set to 3.3 by the value in parentheses determined by dividing the source image size of each individual texture by 100, which is the size of the integrated map projector. Therefore, the size of the integrated map is 3.3 x 300, or 990.

Determination of the material of the integrated map texel (Texel) (S222) is made by obtaining the coordinates in the individual texture map corresponding to the texel of the integrated map by synthesizing the material implemented in the coordinates.

This method is described through the correlation between the individual texture maps and the coordinates of the integrated map synthesized therefrom.

The individual texture maps and the unified map are mapped to the object using a projector to express the texture of the object. At this time, each mapping function exists between the coordinates of the object where the texture is to be expressed and the coordinates of the individual texture map or integration map from which the texture is to be extracted.

As shown in Fig. 5, the coordinate P (x, y, z) in the object is T (coordinate) in coordinates of the individual texture maps T ₁ , T ₂ , T ₃ from which the texture is extracted to express the texture of the object. u _1i , v _1i ), T (u _2i , v _2i ) and T (u _3i , v _3i ) and their mapping functions F ₁ , F ₂ , and F ₃ , and coordinates to extract textures from the integrated map. T (u _xi , v _xi ) is also associated with the mapping function F _x .

Therefore, in the case of synthesizing the material information from the individual texture maps to determine the material of the integrated map texel corresponding to the object coordinates, the coordinates of the corresponding texture map to obtain material information are F ₁ , F ₂ , It is determined by mapping functions such as F ₃ and F _x .

However, an error may occur in a method of determining the coordinates of the individual texture maps representing the material of the integrated map through only the mapping function.

This is because the normal vectors of the projectors used to map the individual texture maps and the integrated map to the object generally have different directions, so projecting polygons in the object onto the individual texture maps and the integrated map, respectively, projected polygon shapes. This is different.

As a result, when scanning the inside in the unit of polygon in the object and determining the material of the corresponding texel of the integrated map, distortion may occur in the corresponding positioning of the texture map to extract the material.

 Therefore, when determining coordinates of individual texture maps corresponding to the integrated texel texture, it is necessary to correct the coordinates of the individual texture maps to be determined in consideration of the shape difference of the polygons projected on each.

6 is a view showing a method of correcting coordinates in a texture map from which a texture is extracted according to an exemplary embodiment of the present invention.

As shown in FIG. 6, the coordinates for determining the texture in the unified map have three vertices and a constant distance ratio. That is, the coordinates to determine the texture in the integrated map have a ratio of T (k, l), vertices v _k and 1-s to s, where T (k, l) is a vertex of the polygons v _i and v _j and t respectively. You will have a distance ratio of 1-t.

The distance ratio is used to determine the coordinates in the individual texture map from which the material is to be extracted. Select to extract the material.

That is, the coordinates in the individual texture map from which the material is to be extracted determine two coordinates and a coordinate having a distance ratio of t to 1-t, and a coordinate ratio at which the distance ratio between the determined coordinates and the remaining vertices is s to 1-s. Determine by calculating

The process first calculates T (k, l) _u = (1-t) ui + tuj, T (k, l) _v = (1-t) vi + tvj in relation to two vertices, and T (i, j) _u = (1-s) uk + s * T (k, l) _u, T (i, j) _v = (1-s) vk + s * Can be expressed by using an expression such as T (k, l) _v. The coordinates in the individual texture maps for which the material is determined in the above equation are determined as (T (i, j) _u, T (i, j) _v).

The extracted materials (color, transparency, etc.) and the extracted coordinates from the coordinates in the individual texture maps determined by the correction are preferably implemented to be recorded for each vertex of the polygons in the integrated map, as shown in FIG. The T ₁ , T ₂ , and T ₃ are materials extracted from individual texture maps, and variables represented by u, v, and subscript indicate coordinates in the texture map in which the materials are expressed.

T _x in the bottom of each vertex is the material for the individual texture map T _1, T _2, and the material determined value from T _3, u _xk, v _xk is the coordinate of each texture map that is the material is extracted (u _1k, v _1k) Coordinates in the unified map corresponding to, (u _2k , v _2k ), (u _3k , v _3k ).

In the step of mapping to the object (S24), the integrated map of which the texture is determined (S22) is mapped to the object, and the mapping operation is performed through the projector of the determined integrated map (S20).

 The mapping operation is a process of mapping the material of the unified map to the material of the object. Hereinafter, the process of mapping the material of the unified map to the background color of the object will be described by comparing the general multi-texturing method.

When creating multiple colormaps into a single unified map image, you must consider the compositing function of each colormap itself.Replace compositing function and previous color that ignore the previous color and replace it with the color you want to apply. There is a modulate synthesis function that multiplies the current color to be applied, and a blending function that takes into account the transparency ratio of the previous color and the current color to be applied.

When creating an integrated map from the color maps including the composition functions, if the composition function included in the color map to which the material is applied after the background color Cin is a replace composition function, the previous color may be ignored, thus creating an integrated map. There is no need to consider.

However, if the synthesis function included in the color map to be synthesized after Cin is a modulated synthesis function and a blending synthesis function that are affected by the previous color, a new algorithm to correct the difference is needed. Do.

This is because in general multitexturing implementation, the object surface color and the color map to be coated are calculated by the composition function and the result is passed to the next applied color map. This is because the integrated map image that is applied is processed in a way that is later synthesized with the surface color, and the result is different.

Hereinafter, the difference between the calculation formula using the general multitexturing scheme and the integrated map scheme according to the present invention will be described in the order of the replace synthesis function, the modulate synthesis function, and the blending synthesis function.

However, the symbols used in the following expressions indicate that Cin represents the surface color of the object, Arep represents the color map with the replace composition function, and Aa or Ab has the blending synthesis function with transparency a or b. Represents a color map with Am, and Am represents a color map with a modulated synthesis function.

First, when applying the color map consisting of Arep, Bm, Ca, to the background color indicated by Cin, the general multitexturing method is A * B * (1-a) + Ca, and by applying the integrated map The equation is A * B * (1-a) + Ca, so there is no difference. This is because the replace composition function of the color map following the background color ignores the previous color and represents the synthesized color.

Second, in the case of applying a color map composed of Aa Bm Cb to Cin, a general multi-texturing formula is first synthesized by the blending synthesis function of Aa in Cin, and thus Cin (1- a) + A a, Next, {Cin (1-a) + A a} * B is synthesized by Bm having a modulated synthesis function, and finally {Cin (1- a) + A a} * B through synthesis with Cb. } You can see that it has an expression of * (1-b) + Cb.

On the other hand, in the formula using the unified map, since Aa Bm Cb is first integrated and applied to the background color, first, the result of Aa Bm is A * B, and then synthesized up to Cb having a blending function { You can find the expression A * B} * (1-b) + Cb. When the synthesized formula is applied to the background color, the synthesized formula is synthesized by Aa by transparency a, so Cin (1-a) + {{A * B} * (1-b) + Cb} * The arithmetic expression of a is obtained.

Third, in the case of applying a color map composed of Am Ba Cm to Cin, the general multitexturing formula is first synthesized by the modulated synthesis function of Am in Cin, and then Cin * A, and then the blending synthesis function. {Cin * A} * (1-a) + Ba by synthesis with Ba, and finally {{Cin * A} * (1-a) + Ba}} * with Cm It can be seen that it has an expression.

On the other hand, in the formula by applying the integrated map, since Am Ba Cm is integrated first and applied to the background color, first, the synthesis result of Am Ba is A * (1-a) + Ba, and then the modulated synthesis function is Branches can be synthesized up to Cm to obtain {{A * (1-a) + Ba} * C. When the synthesized formula is applied to the background color, the synthesized formula is modulated by Am based on the background color. Therefore, the formula of Cin * {{A * (1-a) + Ba} * C is obtained.

As described above, in the case of the blending synthesis function and the modulated synthesis function, there is a difference between the equation of the integrated map method and the equation of the general multi-texturing method, which are different from the blending synthesis function. It describes a new algorithm to correct.

However, the case of the blending synthesis function is determined by the type of the synthesis function applied to the background color, which is determined by the color map following the background color. That is, in the above example, as in the case of synthesizing a color map of Aa Bm Cb to Cin, a color map having a blending synthesis function such as Aa follows Cin. This is because a blending synthesis function is applied to Cin by Aa even if a color map having any synthesis function follows Aa.

Using the generalized algorithm as follows, the blending synthesis function can solve the difference in expression generated by the integrated map method.

For example, when synthesizing the color map in the order of Cin Ag Bm Ca Db, two separate operations are performed first and the result is stored using two buffer values.

The first buffer value stores the result obtained by multiplying the transparency l by (1-l) whenever it is necessary to perform an operation on a subsequent blending synthesis function except for Ag. At this time, Modulate operates as it is. That is, since a color map having two blending synthesis functions represented by Ca and Db follows Ag, the first buffer value has an expression such as B * (1-a) * (1-b).

The second buffer value is multiplied by 1 / g applying Ag transparency to the place where * l is applied to the transparency l for each subsequent blending operation except for Ag.

Here again, Modulate operates as is. That is, the second buffer value has an expression such as A * B * (1-a) (1-b) + Ca * (1-b) * (1 / g) + Db * (1 / g).

Computing this result with Cin * first buffer value * (1- g) + second buffer value * g can give the same result as the operation of general multitexturing. The above equation may be recalculated even if the background color of Cin is changed.

8 is a view showing a state in which an integrated map according to an embodiment of the present invention is implemented.

The individual texture maps represented by T1, T2, and T3 at the bottom left represent each material on the texture coordinates. The mapping function extracts the corresponding coordinate texture of the integrated map shown at the right center through the mapping function to synthesize the integrated map. The synthesized integrated map is mapped to an object through the projector of the integrated map synthesized through the projector of the individual texture map, and the mapping result can be confirmed by the image on the upper left.

FIG. 9 is a diagram illustrating a difference between a result of not applying multitexturing and a result of applying an integrated map according to an embodiment of the present invention.

If you apply five material texture maps to graphics hardware consisting of four texture units, you cannot represent one material.

For example, as shown in FIG. 9 (a), when four color maps and one reflection map are applied to express the material of the Kimchi refrigerator, one material effect beyond the number of resources allowed cannot be expressed. do. That is, as shown in Figure 9 (b), it is possible to see the appearance of the kimchi refrigerator only four color maps are allowed and the effect of the reflection map is not applied.

However, when the multitexturing method using the integrated map according to the present invention is used, four color maps shown in FIG. 9 (a) can be synthesized into one integrated map, as shown in FIG. 9 (c). Kimchi refrigerator material applied to the effect of the map will be able to be implemented.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

According to the multi-texturing method of the present invention as described above and the recording medium recording the same, there are one or more of the following effects.

By using a texture image to be applied to one side of a 3D object in one image within a limited graphic resource, it is possible to provide various real-time rendering effects by different effects.

In addition, there is an advantage to provide an algorithm that can correct the color difference in the multi-texturing method by the integrated map.

1 is a diagram showing how multitexturing is implemented in graphics hardware consisting of three texture units.

2 is a diagram illustrating a multitexturing method according to an embodiment of the present invention.

FIG. 3 is a diagram schematically illustrating a projector of an integrated map synthesized by projectors of individual texture maps having different normal vectors or center points.

4 is a view for explaining a method of determining the size of the integrated map image according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a method of determining coordinates in an integrated map and an individual texture map by applying a mapping function to coordinates in an object.

6 is a diagram illustrating a method of correcting coordinates in a texture map from which a texture is extracted according to an embodiment of the present invention.

7 is a diagram illustrating coordinate information and texture information stored in vertices in an integrated map according to an embodiment of the present invention.

8 is a view showing a state in which an integrated map according to an embodiment of the present invention is implemented.

FIG. 9 is a diagram illustrating a difference between a result of not applying multitexturing and a result of applying an integrated map according to an embodiment of the present invention.

Claims (7)

Determining a projector of the unified map from the projectors of the texture maps to be synthesized; Generating an integrated map by determining an image size and a texel material of the integrated map based on the texture maps to be synthesized; And Mapping the integrated map to an object through the projector of the integrated map. The method of claim 1, The projector of the integrated map is a multi-texturing method characterized in that the normal vector, the center coordinates and the size of the projector is determined based on the projectors of the texture map to be synthesized. The method of claim 1, And the material determination is determined from materials recorded in coordinates in an individual texture map corresponding to the coordinates of the texel. The coordinates in the texture map are derived from the vertex coordinates of the polygons projected onto the texture map. And determining that the material has a ratio equal to a distance ratio between coordinates in the integrated map to be determined and vertex coordinates of the polygon including the same. The method of claim 1, The material of the texture map is a multi-texturing method, characterized in that the color map consisting of colors. The method of claim 5, In the case where the integrated map is determined from a plurality of color maps including a color map Ag having a blending synthesis function that is first synthesized in Cin and is mapped to an object, The material value of the object is determined by a formula of Cin * first buffer value * (1- g) + second buffer value * g, Cin is the background color of the object, A in Ag is the color of the color map, subscript g represents transparency, The first buffer value is a value that is multiplied by the value of (1- transparency of the color map) to the color of the color map synthesized after Ag whenever a color map having a blending function except for Ag is obtained. The second buffer value is multiplied by 1 / g to the part to be multiplied by the transparency in the formula of the blending function of the color map each time a color map having a blending function except for Ag is obtained. Multi-texturing method, characterized in that the result of the expression expression performed. A recording medium on which the method of any one of claims 1 to 6 is recorded by a computer readable program.