JP2006244426A - Texture processing device, picture drawing processing device, and texture processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein management of resources is not easy because various textures are used by a texture mapping method. <P>SOLUTION: A picture drawing computation processing part 34 of a shader unit 30 issues a texture command for specifying three-dimensional texel coordinate values (u, v, w) for referring to a texture structural body 52 for a texture unit 70. A texture reading part 76 of the texture unit 70 receives the three-dimensional texel coordinate values (u, v, w) from the shader unit 30 and reads texel values corresponding to two-dimensional texel coordinates (u, v) corresponding to the third texel coordinate value w in the texture structural body 52. A filter 74 interpolates a texel value read by the texture reading part 76 in accordance with filtering mode set in a register file 72 and provides an interpolated value to the picture drawing computation processing part 34 of the shader unit 30. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a texture processing device, a drawing processing device, and a texture processing method for performing arithmetic processing on drawing data.

  In the three-dimensional computer graphics, a polygon model that expresses an object in a three-dimensional space with a large number of polygons is generally used. In the polygon model drawing process, shading is performed to shade the polygon surface in consideration of the light source, the viewpoint position, the reflectance of the object surface, and the like. Further, in order to generate an image with high realism, texture mapping is performed in which a texture image is pasted on the surface of the polygon model.

  The texture used for texture mapping is usually a two-dimensional texture, but a volume texture with a texture in the depth direction may be used in order to express a higher texture. The volume texture is used for drawing a cross section of the drawing object, or mapping the texture to a drawing object having a three-dimensional structure such as a cloud or a flame or a translucent drawing object.

  In addition, environment mapping may be performed in which the surrounding environment is reflected on the drawing surface as a texture. In cube environment mapping in which an environment texture is projected in advance on each surface of a virtual cube surrounding a drawing object, and the environment texture of each surface of the cube is mapped onto the drawing surface, the environment texture has a six-sided cube map configuration. .

  As described above, there are various types of textures depending on the texture mapping method, and if hardware that can execute dedicated texture operations specific to the method is provided, the circuit scale of the drawing processing device increases and the device cost increases. Become. Further, if hardware is configured according to the texture mapping method, resource management such as registers and memories becomes complicated. In addition, it takes time and effort for programming such as setting specific parameters to use various textures and executing specific commands.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a drawing processing technique that is excellent in terms of resource management, in which various textures can be used uniformly. Another object is to provide a drawing processing technique capable of efficiently switching and using a plurality of textures.

  In order to solve the above-described problem, a texture processing apparatus according to an aspect of the present invention includes a plurality of two-dimensional textures in which values relating to texture are stored as texel values in association with two-dimensional parameter coordinates. A third parameter for designating at least one of the above is applied to the texture storage unit storing the texture structure provided separately from the first and second parameters in the two-dimensional parameter coordinates, and to the surface of the drawing object The texture is designated from the two-dimensional texture corresponding to the designated third parameter in the texture structure by receiving the designation of the third parameter and the designation of the two-dimensional parameter coordinate value on the surface. Texture reading that reads out the texel value corresponding to the two-dimensional parameter coordinate value If, by interpolating the texel values read, and a filter for calculating a value relating to a texture applied to the surface of the drawing object. By specifying a value corresponding to the relationship between the plurality of two-dimensional textures included in the texture structure as the third parameter, different types of the texture structures are uniformly referred to.

  Here, texture is applied to the surface of the drawing object when texture color values are mapped to the drawing surface, as well as texture-related values such as normal vector values and function values. It is also intended to be applied to.

  Another aspect of the present invention is a drawing processing apparatus. This apparatus is provided with a plurality of two-dimensional textures in which values related to texture are stored as texel values in association with two-dimensional parameter coordinates, and a third parameter for designating at least one of the plurality of two-dimensional textures is the 2 A texture storage unit for storing a texture structure that is provided separately from the first and second parameters in the dimension parameter coordinates, and designation of the third parameter for the texture applied to the surface of the drawing target Corresponding to the designated two-dimensional parameter coordinate value from the two-dimensional texture corresponding to the designated third parameter in the texture structure. Texture to be read and applied to the surface of the drawing object Including a texture processing unit for calculating an interpolation value related, using interpolation value for the texture output from the texture processing unit, and a drawing processing unit for drawing processing of the drawing object. The texture structure has a structure in which the number of environmental textures projected on a cube surface virtually provided in the space where the drawing target exists is provided. The drawing processing unit obtains the surface number of the environmental texture mapped to the surface and the two-dimensional parameter coordinate value in the surface based on the reflection vector of the surface of the drawing object, A third parameter is specified to the texture processing unit together with a two-dimensional parameter coordinate value, and the texture processing unit sets the surface number specified as the third parameter by the drawing processing unit in the texture structure. A texel value corresponding to the two-dimensional parameter coordinate value designated by the drawing processing unit is read from the corresponding environment texture, and an interpolation value related to the texture applied to the surface of the drawing object is calculated.

  Yet another aspect of the present invention is a texture data structure. The texture data structure includes a plurality of two-dimensional textures in which texture-related values are stored as texel values in association with two-dimensional parameter coordinates, and a third parameter for designating at least one of the plurality of two-dimensional textures. Has a structure provided separately from the first and second parameters in the two-dimensional parameter coordinates, and the third specified by the texture read command specifying the two-dimensional parameter coordinate values and the third parameter The texel value corresponding to the specified two-dimensional parameter coordinate value can be sampled from the two-dimensional texture corresponding to the parameter, and the plurality of two-dimensional elements included in the structure as the third parameter By specifying a value according to the relationship between textures, Unified Reference Type of the structure so that it may be configured.

  Yet another embodiment of the present invention is a texture processing method. In this method, a plurality of two-dimensional textures in which texture-related values are stored as texel values in association with two-dimensional parameter coordinates are provided, and a third parameter for designating at least one of the plurality of two-dimensional textures is the 2 For a texture memory holding a texture structure provided separately from the first and second parameters in the dimension parameter coordinates, the third parameter and the two-dimensional on the surface for the texture applied to the surface of the drawing object Sampling a texel value corresponding to the specified two-dimensional parameter coordinate value from the two-dimensional texture corresponding to the specified third parameter by executing a texture read command specifying the parameter coordinate value And interpolate the sampled texel values Calculating a value related to the texture applied to the surface of the drawing object, and the third parameter is a value corresponding to the relationship between the plurality of two-dimensional textures included in the texture structure Is specified, different types of the texture structures are uniformly referred to.

  It should be noted that any combination of the above-described constituent elements and a representation of the present invention converted between a method, an apparatus, a system, a computer program, a data structure, etc. are also effective as an aspect of the present invention.

  According to the present invention, the convenience of texture mapping can be improved and the efficiency of texture processing can be improved.

  FIG. 1 is a configuration diagram of a drawing processing apparatus 100 according to the embodiment. The drawing processing apparatus 100 performs a rendering process for generating drawing data to be displayed on a two-dimensional screen based on the three-dimensional model information.

  The rasterizer 10 acquires vertex data of a primitive to be drawn from a memory or another processor or a vertex shader, and converts it into pixel information corresponding to a screen to be drawn. The drawing primitive is a drawing unit of a geometric figure such as a point, a line, a triangle, or a quadrangle when a three-dimensional object is represented by a polygon model, and is data expressed in a vertex unit. The rasterizer 10 performs view conversion in which drawing primitives in a three-dimensional space are converted into graphics on the drawing plane by projection conversion, and further, one column is scanned while scanning the drawing on the drawing plane along the horizontal direction of the drawing plane. Every time it is converted to a quantized pixel.

  The rasterizer 10 develops pixels of the rendering primitive, and for each pixel, a color value expressed by RGB three primary colors, an alpha value indicating transparency, a Z value indicating depth, and a UV coordinate value which is a parameter coordinate for referring to a texture attribute Pixel information including such as is calculated.

  The rasterizer 10 performs the above-described rasterization process in units of a pixel set of a predetermined size including one or more pixels, and sequentially supplies the pixel sets after the rasterization process to the shader unit 30 in units of pixel sets. . The pixel set supplied from the rasterizer 10 to the shader unit 30 is pipeline processed in the shader unit 30. The pixel set is a collection of pixels processed by the rasterizer 10 at a time, and is a unit of rasterization processing, and at the same time, a unit of drawing calculation processing in the shader unit 30.

  The shader unit 30 includes a plurality of pixel shaders that operate asynchronously, and performs pixel drawing processing in parallel by processing a set of pixels each of which is responsible. The shader unit 30 obtains the color value of the pixel by performing shading processing based on the pixel information distributed from the rasterizer 10 in units of pixel sets, and further, when texture mapping is performed, the texture obtained from the texture unit 70 The final color value of the pixel is calculated by combining these color values, and the pixel data is written in the memory 50.

  The texture unit 70 performs processing for mapping texture data to pixels processed in the shader unit 30. In the present embodiment, texture unit 70 uses a texture structure provided with a plurality of two-dimensional textures (hereinafter simply referred to as “texture structure”). In the two-dimensional texture included in the texture structure, an attribute value such as a texture color value is stored as a texel value in association with the two-dimensional parameter coordinates (u, v).

  Note that the two-dimensional texture included in the texture structure may be a one-dimensional texture having only the first parameter u as the position coordinates of the texel as a special case. In the two-dimensional texture, assuming that the second parameter v is always 0, the one-dimensional texture can be handled as a special case of the two-dimensional texture by ignoring the v direction. Therefore, in the following description, the texture dimension is generally assumed to be two-dimensional for the purpose of including a one-dimensional texture as a special case.

  In order to refer to the texel value from at least one of the plurality of two-dimensional textures included in the texture structure, the third parameter w for designating at least one of the two-dimensional textures included in the texture structure is a texel position. Are provided separately from the first parameter u and the second parameter v in the two-dimensional parameter coordinates (u, v) for designating.

  The texture to be mapped to the pixels on the polygon surface is specified by the three-dimensional parameter coordinates (u, v, w) in combination with the third parameter w and the two-dimensional parameter coordinates (u, v) defined on the polygon surface. Is done. Hereinafter, the parameter coordinates are referred to as texel coordinates, and the third parameter w is also referred to as third texel coordinate w. The third texel coordinate w is basically at least one of a plurality of two-dimensional textures included in the texture structure. Note that while the two-dimensional texel coordinates correspond to the width and height of the texture, the third texel coordinates do not necessarily correspond to the depth of the texture. This is because how the third texel coordinate w is given depends on the relationship between a plurality of two-dimensional textures included in the texture structure.

  The texture unit 70 acquires the three-dimensional texel coordinate value (u, v, w) of the texture structure mapped to the pixel from the shader unit 30, and the two-dimensional corresponding to the third texel coordinate w in the texture structure. A texel value corresponding to the two-dimensional texel coordinate value (u, v) is read from the texture, the read texel value is interpolated, and the interpolated value is supplied to the shader unit 30.

  The shader unit 30 further performs processing such as fogging and alpha blending on the drawing data held in the memory 50, obtains a final pixel color value, and updates the pixel data in the memory 50.

  The memory 50 has an area that functions as a frame buffer that stores pixel data generated by the shader unit 30 in screen coordinates. The pixel data stored in the frame buffer may be a final drawn image or an intermediate image in the process of shading. The pixel data stored in the frame buffer is output to the display device and displayed.

  FIG. 2 is a diagram illustrating the configuration of the shader unit 30 and the texture unit 70.

  Configuration information necessary for texture mapping is set in each of the register file 32 of the shader unit 30 and the register file 72 of the texture unit 70. The configuration information includes various parameters such as a base address for collectively referring to the texture structures 52 stored in the memory 50 and a filtering mode for texture mapping.

  The drawing operation processing unit 34 of the shader unit 30 designates three-dimensional texel coordinate values (u, v, w) for referring to the texture from the texture structure 52 based on the configuration information set in the register file 32. By issuing the texture command to the texture unit 70, the texture interpolation value of the texture mapped to the pixel is acquired from the texture unit 70. The drawing calculation processing unit 34 calculates the final color value of the pixel using the texture interpolation value acquired from the texture unit 70, and writes it in the memory 50 as the drawing data 54.

  The texture reading unit 76 of the texture unit 70 receives the three-dimensional texel coordinate values (u, v, w) from the shader unit 30. The texture reading unit 76 adds the offset value determined depending on the third texel coordinate value w to the base address of the texture structure 52 held in the register file 72, thereby specifying the specified third texel coordinate value w. A texture reference address corresponding to is generated. The texture reading unit 76 reads the texel value corresponding to the two-dimensional texel coordinates (u, v) in accordance with the filtering mode set in the register file 72 from the texture specified by the reference address. The texture reading unit 76 gives the read texel value to the filter 74.

  The texture reading unit 76 is configured to refer to the texture structure 52 cached in the cache memory provided in the texture unit 70 without directly referring to the texture structure 52 stored in the memory 50. May be.

  In addition to the three-dimensional texel coordinate value (u, v, w), the drawing calculation processing unit 34 may issue a texture command specifying a LOD (level of detail) value indicating the drawing detail level of the drawing target object as a parameter. it can. In that case, the texture reading unit 76 refers to the mipmap texture having a resolution level corresponding to the LOD value in the texture structure 52 having the structure of the mipmap texture.

  The filter 74 performs interpolation of the texel value read by the texture reading unit 76 according to the filtering mode set in the register file 72, and provides the interpolation value to the drawing calculation processing unit 34 of the shader unit 30.

  The filter 74 may perform trilinear sampling that performs interpolation in the direction of the w direction or the resolution level of the mipmap on the bilinear interpolation result in the u and v2 directions using a multistage interpolation calculator. it can. The filter 74 can also perform monolinear sampling and bilinear sampling in addition to trilinear sampling by selectively functioning a multistage interpolation calculator.

  In monolinear sampling, the nearest texel of the designated texel coordinate (u, v) is sampled from each of the two neighboring textures corresponding to the third texel coordinate w, and is interpolated between the two neighboring textures. When the LOD value is designated, the nearest texel of the designated texel coordinate (u, v) is sampled from each of the two neighboring resolution level textures corresponding to the LOD value among the resolution levels of the mipmap. Interpolated between two neighboring resolution levels.

  In bilinear sampling, four neighboring texels at designated texel coordinates (u, v) are sampled from the texture corresponding to the third texel coordinates w, and are interpolated in two directions u and v. When the LOD value is specified, four neighboring texels at the specified texel coordinates (u, v) are sampled from the texture corresponding to the LOD value within the resolution level of the mipmap and interpolated in two directions u and v. Is done.

  In the trilinear sampling, four neighboring texels of designated texel coordinates (u, v) are sampled from each of two neighboring textures corresponding to the third texel coordinate w, and interpolated in two directions of u and v with each texture. Above, further interpolation is performed between two neighboring textures. When the LOD value is designated, four neighboring texels at the designated texel coordinates (u, v) are sampled from each of the two neighboring resolution level textures corresponding to the LOD value among the resolution levels of the mipmap. Then, after interpolating in two directions u and v at each resolution level, further interpolation is performed between two neighboring resolution levels.

  The filter 74 is switched to one of the interpolations according to the filtering mode set in the register file 72 and executed. Note that the filter 74 can also perform point sampling in which the nearest texel of the designated texel coordinate (u, v) is sampled and output as it is without causing any interpolation calculator to function.

  Furthermore, the filter 74 can perform operations other than linear interpolation by appropriately modifying the functional configuration of the difference unit, multiplier, and adder of the interpolation operation unit and adding some modifications to the operation processing. It is also possible to perform useful calculations other than bilinear interpolation and trilinear interpolation. Accordingly, the filter 74 can execute a calculation for obtaining a deviation of texel coordinates (u, v), which will be described later, and a calculation for obtaining a LOD value of a drawing surface to which the texel coordinates (u, v) are mapped.

  FIG. 3 is a diagram for explaining the data structure of the texture structure 52 stored in the memory 50 of FIG. As already described, the texture structure 52 is provided with a plurality of two-dimensional textures, and is configured such that any two-dimensional texture can be designated by the third parameter w. Here, as an example of a data structure for storing a plurality of two-dimensional textures, a configuration in which a plurality of two-dimensional textures are arranged in the vertical direction in the figure will be described. Any arrangement of a plurality of two-dimensional textures on the memory is possible as long as it can be addressed.

  In the following, for convenience, the term “layer” is used to describe the vertical direction of a plurality of two-dimensional textures arranged side by side in the vertical direction as shown in FIG. It does not mean that there is a relationship in the form of a layer, it simply refers to the position of the vertical alignment.

  Furthermore, the two-dimensional texture of each layer can have a structure of a set of mipmap textures having different resolutions in stages. In the horizontal direction of the figure, the resolution level of the mipmap (hereinafter simply referred to as “mip level”) is shown.

  When the mip level 0 is viewed in the vertical direction, texture A0, texture A1, and texture A2 having the same height and width are arranged in the order of layer 0, layer 1, and layer 2. Also for mip level 1, texture B0, texture B1, and texture B2 having the same height and width are arranged in the order of layer 0, layer 1, and layer 2. The width and height of the textures B0 to B2 at the mip level 1 are half the width and height of the textures A0 to A2 at the mip level 0, respectively. Similarly, the widths and heights of the textures C0 to C2 arranged in the layers 0 to 2 of the mip level 2 are respectively half the widths and heights of the textures B0 to B2 of the layers 0 to 2 of the mip level 1. .

  When viewed in the horizontal direction, in layer 0, textures having different mip levels are arranged in the order of texture A0 of mip level 0, texture B0 of mip level 1, and texture C0 of mip level 2. Similarly, textures with different mip levels are also stored in layers 1 and 2.

  The number of layers and the number of mip levels in the texture structure 52 can be changed by setting the register file 72. Whether or not to provide a mipmap texture structure to the texture structure 52 can also be selected by setting the register file 72. When the mipmap texture is not used, the configuration is such that one layer of two-dimensional texture of the same size is provided for each layer. In FIG. 3, the texture structure 52 that does not use the mipmap texture has a data structure in which only the textures A0, A1, and A2 of the mip level 0 exist.

  Whether the texture structure 52 is provided with a layer structure can be selected by setting the register file 72. When a layer structure is not provided, a structure in which a plurality of mip-level textures are provided for one layer is provided. In FIG. 3, the texture structure 52 without the layer structure has a data structure in which only the textures A0, B0, and C0 of the layer 0 exist. The texture structure 52 includes a texture having a single layer and a plurality of mip levels as a special case. Further, a normal texture having one layer and no mip level is also handled as a special case of the texture structure 52.

  The texture reading unit 76 refers to the texture of the specified mip level M belonging to the specified layer N by specifying the layer number N and the mip level M for the texture structure 52 stored in the memory 50. For example, when layer 2 and mip level 1 are designated, texture B1 of mip level 1 belonging to layer 2 can be referred to. The texture reading unit 76 samples the texel value of the texture by specifying the two-dimensional texel coordinates (u, v) in the texture of the specified layer and mip level.

  The texel value may be a color value of three RGB colors or a color value index as a value related to the texture. In the latter case, the index is converted into an actual color value by referring to the color lookup table. When bump mapping is performed as an example of texture mapping, a normal vector is stored in the texture. In this case, the texel value is the value of the normal vector. In addition, when using a procedural texture that generates a texture by a program based on a parameter, the texel value is a parameter value or a function value.

  Several examples of sampling texel values from the texture structure 52 will be described with reference to FIGS.

  FIG. 4 is a diagram for explaining bilinear sampling. The texture reading unit 76 obtains the reference layer N as the layer corresponding to the third texel coordinate w, and obtains the reference mip level M as the mip level corresponding to the designated LOD value. The texture reading unit 76 reads four texels 53 a in the vicinity of the point represented by the texel coordinate value (u, v) from the texture 51 a specified by the reference layer N and the reference mip level M.

  The filter 74 obtains an interpolation value corresponding to the texel coordinate value (u, v) by linearly interpolating the values of the four neighboring texels 53a in the u direction and the v direction.

  FIG. 5 is a diagram for explaining trilinear sampling between mip levels. The texture reading unit 76 obtains the reference layer N as a layer corresponding to the third texel coordinate w, and obtains two reference mip levels M and M + 1 as mip levels corresponding to the designated LOD value. The texture reading unit 76 reads four texels 53a in the vicinity of the point represented by the texel coordinate value (u, v) from the first texture 51a specified by the reference layer N and the first reference mip level M. The texture reading unit 76 reads four texels 53b in the vicinity of the point represented by the texel coordinate value (u, v) from the second texture 51a specified by the reference layer N and the second reference mip level M + 1. .

  The filter 74 performs a linear interpolation between the value of the texel 53a near 4 of the first reference mip level M and the value of the texel 53b near 4 of the second reference mip level in three directions u, v, and mip level. By performing linear interpolation, an interpolation value corresponding to the texel coordinate value (u, v) is calculated.

  FIG. 6 is a diagram for explaining monolinear sampling between layers. The texture reading unit 76 obtains two reference layers N and N + 1 as layers corresponding to the third texel coordinate w, and obtains a reference mip level M as a mip level for the designated LOD value. The texture reading unit 76 reads the texel 53c that is closest to the point represented by the texel coordinate value (u, v) from the first texture 51c specified by the first reference layer N and the mip level M. Further, the texture reading unit 76 reads the texel 53d that is closest to the point represented by the texel coordinate value (u, v) from the first texture 51d specified by the second reference layer N + 1 and the mip level M.

  The filter 74 calculates an interpolated value corresponding to the texel coordinate value (u, v, w) by linearly interpolating the value of the texel 53c of the first reference layer N and the value of the texel 53d of the second reference layer N + 1. To do.

  In FIG. 6, in each of the two reference layers N and N + 1, four texels in the vicinity of the point represented by the texel coordinate value (u, v) are sampled, and u, between the two reference layers N and N + 1, Trilinear interpolation that linearly interpolates in the three directions v and w can also be performed.

  FIG. 7 is a flowchart for explaining the procedure of the texture mapping process by the texture unit 70.

  The shader unit 30 designates texel coordinate values (u, v, w) and LOD values for referring to the texture structure 52 to the texture unit 70 (S10). Here, the LOD value input from the shader unit 30 is called an external LOD value in order to distinguish it from an internal LOD value on the drawing surface determined by a deviation of texel coordinates described later. The external LOD value is determined according to the Z value of the drawing object.

  More specifically, the shader unit 30 issues a texture set command tset specifying the external LOD value and the third texel coordinate value w as parameters, and then specifies the two-dimensional texel coordinate value (u, v) as parameters. Issued texture load instruction tld. The texture unit 70 starts the texture mapping operation in response to the issue of the texture load instruction tld.

  The texture unit 70 converts the data type of the input parameter. The shader unit 30 performs an operation with a floating-point number, but the texture unit 70 uses a fixed-point number that can execute the calculation quickly in order to efficiently use the texture mapping hardware. Therefore, the texture unit 70 converts the data type of parameters such as the input texel coordinates from floating point to fixed point.

  The filter 74 calculates a deviation indicating the inclination in the u direction and the v direction in the texel coordinates (u, v) as follows (S12).

  In the drawing area of 2 pixels vertically and horizontally, the texel coordinates of 4 pixels (x, y), (x + 1, y), (x, y + 1), (x + 1, y + 1) are (U0, V0), (U1, V1). , (U2, V2), (U3, V3).

The filter 74 obtains a change amount du / dx, du / dy, dv / dx, dv / dy of the texel coordinate (u, v) with respect to a change of the pixel coordinate (x, y) by a deviation of the following expression.
du / dx = ((U1-U0) + (U3-U2)) / 2
dv / dx = ((V1-V0) + (V3-V2)) / 2
du / dy = ((U2-U0) + (U3-U1)) / 2
dv / dy = ((V2-V0) + (V3-V1)) / 2

  These deviations indicate the amount by which the texel coordinates locally change in the x and y directions of the screen, and are used to obtain the LOD value of the curved surface to which the texture is mapped.

  Based on the deviation of the texel coordinates (u, v), the filter 74 calculates the LOD value at the texel coordinates (u, v) as follows (S14).

Px = [(du / dx) ² + (dv / dx) ² ] ^1/2
Py = [(du / dy) ² + (dv / dy) ² ] ^1/2
LOD = log ₂ (max (Px, Py))

  The LOD value of the texel coordinates (u, v) calculated in this way is referred to as an internal LOD value in order to distinguish it from the external LOD value specified from the shader unit 30. The filter 74 adds the external LOD value as an offset to the internal LOD value. The LOD value offset by the external LOD value is called a bias LOD value.

  The filter 74 selects a filter for drawing the texture according to the bias LOD value (S16). The filter includes a reduction filter and an enlargement filter. When the bias LOD value is equal to or lower than a predetermined value, that is, when the drawing detail level is equal to or lower than a predetermined level, the enlargement filter for enlarging the texture is selected. In this case, that is, when the drawing detail level is higher than a predetermined level, a reduction filter for reducing the texture is selected.

  The filter 74 performs correction processing at the mip level (S18). The texture unit 70 first obtains the mip level based on the bias LOD value obtained in step S14. When interpolation between mip levels is not performed, 0.5 is added to the bias LOD value and rounded to an integer value to obtain the mip level M closest to the LOD value. When interpolation between mip levels is performed, a value obtained by rounding the bias LOD value to an integer value is obtained as the first mip level M, and a value obtained by adding 1 to the first mip level is obtained as the second mip level M + 1. As a result, two mip levels in the vicinity of the bias LOD value are obtained.

Next, the filter 74 corrects the texel coordinate value (u, v) and the texture size based on the mip level M thus obtained. Since the texel coordinate value (u, v) is specified for the texture of the mip level 0, when referring to the texture of the mip level M, it is necessary to correct it to a value corresponding to the texture size of the mip level M. is there. The first and second texel coordinate values u and v corresponding to the mip level M are obtained by dividing the first and second texel coordinate values u and v at the original mip level 0 by 2 ^M , respectively. Since the w direction is independent of the mip level, the third texel coordinate value w is not corrected.

Further, the filter 74 corrects the texture size of the mip level 0 set in the register file 72 to a size corresponding to the mip level M. This is obtained by dividing the height and width of the original mip level 0 texture by ^2M , respectively.

  The texture reading unit 76 obtains a texel number that designates a texel within the two-dimensional texture of the texture structure 52 (S20). When the texels stored in the texture are regarded as a two-dimensional array, the texel number is an index of the two-dimensional array that specifies the texels in the texture.

  The texel coordinate value (u, v) is a real value, but the texel number is represented by a subscript (i, j) obtained by rounding the texel coordinate value (u, v) to an integer. When a texel number near the point indicated by the texel coordinates (u, v) is designated by a texel number, the texel numbers are (i, j), (i + 1, j), (i, j + 1), (i + 1, j + 1). 4).

  In the case of the texture structure 52, since a plurality of two-dimensional textures are provided in the layer direction and the mip level direction, a third index k for specifying the layer number and a fourth index m for specifying the mip level are further added. The texel number is represented by (i, j, k, m). For example, when interpolation is performed between two layers N and N + 1, the texel numbers are designated as (i, j, N, M) and (i, j, N + 1, M). When interpolation is performed between two mip levels M and M + 1, the texel numbers are designated as (i, j, N, M) and (i, j, N, M + 1).

  The filter 74 calculates an interpolation coefficient used for filtering (S22). The interpolation coefficient is given by the decimal part of the first and second texel coordinate values u and v corrected to correspond to the mip level M. The u-direction interpolation coefficient α is the decimal part of the value of the first texel coordinate u at the mip level M, and the v-direction interpolation coefficient β is the decimal part of the value of the second texel coordinate v at the mip level M. When interpolation in the w direction, that is, interpolation between layers, is performed, the interpolation coefficient γ in the w direction is given by the decimal part of the value of the third texel coordinate value w. When interpolation according to the LOD value, that is, interpolation between mip levels, the interpolation coefficient δ in the mip level direction is given by the fractional part of the bias LOD value.

  The texture reading unit 76 calculates a texture reference address (S24). The texture reading unit 76 sets the texture size of each mip level belonging to each layer to the base address of the texture structure 52 set in the register file 72 during configuration until the layer number is N and the mipmap level is M. By adding, an address for referring to the texture of the designated layer number N and mip level M is calculated.

  The texture reading unit 76 samples the texel designated by the texel number obtained in step S20 based on the texture reference address obtained in step S24 (S26). In the case of point sampling, one texel is sampled, but in the case of bilinear interpolation, four neighboring texels are sampled.

  The filter 74 filters the sampled texel by bilinear interpolation, trilinear interpolation, or the like (S28). The filter 74 converts the interpolation value obtained by filtering into a floating point handled by the shader unit 30 and outputs it (S30).

  Although description is omitted in the procedure of the texture mapping process, either a clamp process or a repeat process is performed as a wrap mode when the texel coordinates are at a position where the texture is not sampled. When sampling a texel, the texture image may be crossed over, so processing in the wrap mode is required. In the clamping process, the texel coordinates are clamped within a predetermined value range. In repeat processing, texel numbers are circulated so that the same texture is repeated.

  The texture structure 52 used by the drawing processing apparatus 100 according to the present embodiment described above is generally a plurality of 2 that can be referred to in a unified manner using three-dimensional texel coordinates (u, v, w). Although it is a collection of dimensional textures, it does not need to have any relationship between two or more two-dimensional textures, or it can be used freely according to the application. .

  For example, the texture structure 52 can be used as a so-called “layer texture”. The layer texture is formed by layering a plurality of two-dimensional textures in association with each other, and depending on the application, the texture may be premised on being layered. In this case, the third texel coordinate w is used to specify a layer number. The term “layer” used in describing the texture structure 52 in the above embodiment does not mean a layer in the narrow sense of the term “layer texture”, but simply a texture structure. This is used to identify the positions of a plurality of two-dimensional textures arranged side by side in the body 52.

  The texture structure 52 may be used as a so-called “volume texture”. The volume texture has a relation in the depth direction between a plurality of two-dimensional textures, and is configured as a texture having a dimension of depth in addition to the width and height. In this case, the third texel coordinate w is used to specify the depth value. In the volume texture, since the layer of the texture structure 52 corresponds to the depth, interpolation between layers makes sense.

  In the above embodiment, the maximum number of layers of the texture structure 52 is limited to 8, 16, 32, etc. depending on hardware implementation, but the texture structure 52 is used as a volume texture. In some cases, it may be desirable to further increase the depth direction. For example, when a procedural texture is used, a number of noise textures are generated by a noise generation algorithm based on Perlin, and the texture is given by superimposing them on multiple layers. In such a three-dimensional texture, for example, 64 layers may be required as the depth direction.

  In such a case, the number of layers can be increased by using the texel component of each texture of the texture structure 52 as a layer. Each texel of the texture typically has four components for storing RGB and alpha values. If this component is associated with a layer and each texel is handled as a set of values of 4 layers, even if the maximum number of layers of the texture structure 52 is 16, it is handled as 16 × 4 = 64 layers. Can do. As a result, 64 layers can be multiplexed as a noise texture.

  The shader unit 30 executes a texture command specifying a value from 0 to 63 as the third texel coordinate value w in order to generate a noise texture. However, since the texture unit 70 processes the 16-layer texture structure 52 to the last, the texture reading unit 76 obtains a quotient and a remainder obtained by dividing the third texel coordinate value w by 4, and the quotient from 0 to 15 is obtained. Get the layer number, and get the component number by the remainder. The texture reading unit 76 can sample the corresponding texel from the texture structure 52 by referring to the designated component in the texture of the designated layer using the acquired layer number and component number.

  As described above, the texture structure 52 is generally described as a collection of a plurality of independent two-dimensional textures, and has been described as being usable as a so-called “layer texture” or “volume texture”. Further, it can be used to store six-sided environment textures used in cube environment mapping (hereinafter simply referred to as cube mapping). Hereinafter, a method of performing the cube mapping process by the drawing processing apparatus 100 of the present embodiment using the texture structure 52 will be described.

  FIG. 8 is a diagram showing a virtual cube surrounding a drawing object in cube mapping and its surface. In cube mapping, as shown in the figure, each plane is parallel to the xy plane, yz plane, and zx plane of the world coordinate system (x, y, z) defined in the world coordinate space in which the drawing object exists. Assume a virtual cube. The orientation of each face of the virtual cube has six directions of positive X, negative X, positive Y, negative Y, positive Z, and negative Z, and each face of the virtual cube is identified by these six directions. An environmental texture to be mapped onto the drawing object is projected in advance on each surface of the cube.

  FIG. 9 is a development view of the virtual cube of FIG. 8 in the direction of each axis S, T of the texture coordinates (S, T) and the direction of each axis x, y, z of the world coordinates (x, y, z). It is a figure explaining a correspondence. The S-axis and T-axis of the texture coordinates (S, T) are defined in the direction shown in FIG. For the positive X plane, the texture coordinate S-axis is in the negative direction (-z) of the world coordinate z-axis, and the texture coordinate T-axis is in the negative direction (-y) of the world coordinate y-axis. For the negative X plane, the S axis is in the positive z-axis direction of the world coordinates (z), and the T axis is in the negative y-axis direction of the world coordinates (-y).

  Similarly, the S axis and T axis of the positive Y plane are respectively in the positive direction (x) of the x axis of the world coordinates and the positive direction (z) of the z axis, and the S axis and T axis of the negative Y plane are , Respectively in the positive direction (x) of the x-axis of the world coordinates and in the negative direction (−z) of the z-axis. Further, the S axis and T axis of the positive Z plane are respectively in the positive direction (x) of the x axis of the world coordinate and the negative direction (−y) of the y axis, and the S axis and T axis of the negative Z plane are , Respectively, in the negative direction (−x) of the x axis of the world coordinates and in the negative direction (−y) of the y axis.

  In cube mapping, a reflection vector r on the drawing surface is calculated, and it is determined which surface of the virtual cube intersects the direction of the reflection vector r. The surface of the virtual cube where the reflection vectors r intersect is called the target surface. The target surface is a cube surface indicated by the maximum component (referred to as a major component) of the reflection vector.

  When the target surface is determined, the major component of the reflection vector r and the major axis direction are determined. When the component of the reflection vector r is (vx, vy, vz), when the target surface with respect to the reflection vector r is positive X, the major axis direction is the positive direction of the x axis (this is denoted as + VX), The major component is the x component vx of the reflection vector. When the target surface is negative X, the major axis direction is the negative x-axis direction (−VX), and the major component is the x component vx of the reflection vector.

  Similarly, when the target surface is positive Y, the major axis direction is + VY and the major component is vy. When the target surface is negative Y, the major axis direction is −VY and the major component is vy. When the target surface is positive Z, the major axis direction is + VZ and the major component is vz. When the target surface is negative Z, the major axis direction is −VZ and the major component is vz.

  A point obtained by projecting the end point (vx, vy, vz) of the reflection vector r onto the target surface in the major axis direction is a texture point mapped onto the drawing surface, and the texture coordinates (Sc, Tc) of the point are It is expressed using the component of the reflection vector. Here, as described with reference to FIG. 9, the direction of the S-axis and T-axis of the texture coordinates on each cube surface may be opposite to the corresponding axis of the world coordinates. For example, when the target plane is positive X, the S-axis and T-axis of the texture coordinates are the −z direction and the −y direction, respectively, as described in FIG. (Sc, Tc) is given by (−vz, −vy) using the z component and y component of the reflection vector. Similarly, in the case of other target surfaces, the texture coordinates can be expressed using the component of the reflection vector r.

  FIG. 10 is a diagram collectively showing the correspondence between the target surface, the texture coordinates (Sc, Tc) on the target surface, and the major component.

  When the major axis direction is + VX, the target surface is positive X, Sc is −vz, Tc is −vy, and the major component is vx. When the major axis direction is −VX, the target surface is negative X, Sc is vz, Tc is −vy, and the major component is vx.

  When the major axis direction is + VY, the target surface is positive Y, Sc is vx, Tc is vz, and the major component is vy. When the major axis direction is -VY, the target surface is negative Y, Sc is vx, Tc is -vz, and the major component is vy.

  When the major axis direction is + VZ, the target surface is positive Z, Sc is vx, Tc is -vy, and the major component is vz. When the major axis direction is −VZ, the target surface is negative Z, Sc is −vx, Tc is −vy, and the major component is vz.

  As shown in FIG. 10, since the correspondence relationship between the target surface, texture coordinates (Sc, Tc), and the major component is uniquely determined by the major axis direction, the major axis direction may be designated to designate the cube map. .

  FIGS. 11A to 11D are diagrams illustrating a method of using the texture structure 52 as a cube map.

  FIG. 11A shows the data structure of the texture structure 52 for cube maps. The layer direction of the texture structure 52 is associated with a cube surface, and a cube map that is an environmental texture of each surface of the virtual cube is stored as a two-dimensional texture in each layer. The number of layers of the texture structure 52 is 6 corresponding to the six faces of the virtual cube. The layer number corresponds to the map ID that identifies the cube surface.

  The map ID corresponds to the major axis direction. If the major axis direction is determined, the cube map of each surface can be selected by the corresponding map ID. As for the correspondence relationship between the map ID and the major axis direction, major axes + VX, −VX, + VY, −VY, + VZ, and −VZ are associated with map IDs 0 to 5 as shown in FIG. Each mip level is provided with a cube map having different resolutions. Here, an example of three levels of resolution of mip levels 0 to 2 is shown.

  FIG. 11B is a diagram illustrating a correspondence relationship between the texture of each layer at the mip level 0 and each surface of the virtual cube. The texture of map ID 0 (referred to as map 0) in FIG. 11A corresponds to the environmental texture of the positive X plane of the virtual cube in FIG. The texture of map ID1 (map 1) corresponds to the environmental texture of the negative X plane of the virtual cube. Hereinafter, similarly, Map 2, Map 3, Map 4, and Map 5 correspond to the environmental textures of the positive Y plane, negative Y plane, positive Z plane, and negative Z plane of the virtual cube, respectively.

  FIG. 11C is a diagram illustrating a correspondence relationship between the texture of each layer of the mip level 1 whose resolution is halved compared to the mip level 0 and each surface of the virtual cube. FIG. 11D is a diagram showing a correspondence relationship between the texture of each layer of the mip level 2 and the resolution of the mip level 0 of each layer of the virtual cube. The correspondence between layers and cube surfaces is the same as in FIG.

  The map ID can be specified by the third texel coordinate w as in the case of specifying the layer number. Therefore, cube mapping using a mipmap can be performed using a texture command that specifies three-dimensional texel coordinates (u, v, w) and LOD values.

  FIG. 12 is a flowchart for explaining the procedure of cube mapping processing by the drawing processing apparatus 100.

  The drawing calculation processing unit 34 of the shader unit 30 calculates the reflection vector r on the drawing surface (S40). The reflection vector r can be obtained by the calculation formula r = 2 (n · e) ne using the line-of-sight vector e and the normal vector n of the drawing surface.

  The drawing calculation processing unit 34 calculates the major axis direction corresponding to the map ID and the texture coordinates (Sc, Tc) on the target surface based on the major component of the reflection vector r (S42). This is as described in FIG.

  The drawing calculation processing unit 34 converts the texture coordinates (Sc, Tc) to texel coordinates (u, v) (S44). The texel coordinates (u, v) are normalized by dividing the texture coordinates (Sc, Tc) by the absolute value | major | of the major component when the width and height of the texture are width and height, respectively. It can be obtained as shown in the equation.

u = (width / 2) · (Sc / | major | +1)
v = (height / 2). (Tc / | major | +1)

  Here, values that match the width and height values of the texture set in the register file 72 of the texture unit 70 are also set in the register file 32 of the shader unit 30, and the drawing operation processing unit 34 makes the register file 32. Can be referenced from.

  The drawing calculation processing unit 34 designates the three-dimensional texel coordinates (u, v, w) including the two-dimensional texel coordinates (u, v) thus obtained and the third texel coordinates w for designating the map ID as parameters. A texture command is issued to the texture unit 70. When the mipmap is used, an external LOD value is further specified as a parameter in the texture command.

  More specifically, the drawing calculation processing unit 34 issues a texture set command tset in which the external LOD value and the third texel coordinate value w that is a map ID are specified as parameters, and then a two-dimensional texel coordinate value ( A texture load instruction tld with u, v) designated as parameters is issued. The texture unit 70 starts the texture mapping operation in response to the issue of the texture load instruction tld.

  The texture unit 70 performs a cube mapping process using the texture structure 52 based on the three-dimensional texel coordinates (u, v, w) and the external LOD value designated by the drawing calculation processing unit 34 (S46). This cube mapping process can be performed in the same manner as the texture mapping process shown in the flowchart of FIG. 7 except that the third texel coordinate w indicates the map ID. In cube mapping, interpolation between layers does not make sense and is not performed.

  As described above, according to the drawing processing apparatus 100 of the present embodiment, it is possible to specify a three-dimensional texel coordinate (u, v, w) and sample and interpolate a texel from the texture structure 52. The third texel coordinate w is generally used to specify at least one of a plurality of two-dimensional textures included in the texture structure 52. When the texture structure 52 is used as a layer texture, the layer number is set. If the texture structure 52 is used as a volume texture to specify, it can also be used to specify a parameter relating to depth. Furthermore, if the layer of the texture structure 52 is associated with the cube surface, the texture structure 52 can be handled as a texture storing a six-sided cube map, and by specifying the cube surface as the third texel coordinate, Can do cube mapping.

  Thus, depending on the meaning of the third texel coordinate w, the texture structure 52 can be handled as a collection of a plurality of independent two-dimensional textures, or can be handled as a layer texture in which the two-dimensional texture is formed in layers. Since it can be handled as a volume texture having a dimension in the depth direction or as a six-sided cube map texture, the same hardware configuration and the same interface for texture mapping for processing the texture structure 52 are used as a layer texture. , Volume texture and cube map texture can be used for both purposes. Therefore, the circuit scale of the texture unit 70 can be kept small, and resource management such as registers, caches, and memories in the texture unit 70 can be facilitated. In addition, since the interface is unified, programming of the texture mapping process is easy.

  Various parameters such as address information for referring to the texture structure 52 and filtering mode of texture mapping using the texture structure 52 can be set in the register file by one configuration. Even if the two-dimensional texture in the texture structure 52 is referred by switching layers, it is not necessary to change register setting information, that is, context, and texture mapping can be performed efficiently without context switching overhead. In addition, since the texture structure 52 can use a plurality of textures, high rendering quality can be realized. Thus, according to the present embodiment, it is possible to improve drawing quality by using a plurality of textures while maintaining processing efficiency.

  Further, in the cube mapping process by the drawing processing apparatus 100 according to the present embodiment, the reflection vector is calculated, and the calculation for obtaining the texel coordinates from the reflection vector is performed in the drawing operation processing unit 34 of the shader unit 30, and the cube map is referred to. The texture unit 70 performs processing for sampling and interpolating the texel values. Since the texture unit 70 has a hardware configuration dedicated to texture mapping by the interpolation calculator, it has a high texture calculation capability. On the other hand, the shader unit 30 has an ability to execute a complicated calculation process by a program, and can execute a complicated calculation such as calculation of a reflection vector at high speed. In the rendering processing apparatus 100 according to the present embodiment, processing that requires a high level of computing ability among cube mapping processing is performed by the shader unit 30, and processing related to texture computation is performed by the dedicated texture unit 70. The processing is shared to improve the efficiency of the drawing process of the entire drawing processing apparatus 100.

  The present invention has been described based on the embodiments. The embodiments are exemplifications, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. . Such a modification will be described.

  In the above description, the interpolation between layers and the interpolation between mip levels were performed between two layers and between two mip levels. However, the interpolation should be performed using three or more layers or mip levels. Also good. Further, the number of texels to be sampled is not limited to 4 neighboring texels. You may sample 8 neighboring texels and interpolate between them.

  In the above description, isotropic texel sampling has been described. However, anisotropic filtering may be performed. Anisotropic texel sampling is particularly effective when the UV plane of texel coordinates is large with respect to the XY plane of the screen. In anisotropic texel sampling, the magnitude and direction of changes in texel coordinates on the XY plane of the screen are obtained, and point sampling, bilinear sampling, trilinear sampling, etc. are repeated in the direction of the change according to the magnitude of the change. Maintain the drawing quality.

It is a block diagram of the drawing processing apparatus which concerns on embodiment. It is a figure which shows the structure of the shader unit of FIG. 1, and a texture unit. It is a figure explaining the data structure of the texture structure of FIG. It is a figure explaining bilinear sampling. It is a figure explaining the trilinear sampling between the resolution levels of a mipmap. It is a figure explaining the monolinear sampling between layers. It is a flowchart explaining the procedure of the texture mapping process by the texture unit which concerns on embodiment. It is a figure which shows the virtual cube which surrounds the drawing target object in cube mapping, and its surface. FIG. 9 is a diagram for explaining a correspondence relationship between the direction of each axis of texture coordinates and the direction of each axis of world coordinates in the developed view of the virtual cube of FIG. 8. It is a figure which shows collectively the correspondence of the target surface in cube mapping, the texture coordinate on a target surface, and a major component. It is a figure explaining the method of using a texture structure as a cube map. It is a flowchart explaining the procedure of the cube mapping process by the drawing processing apparatus which concerns on embodiment.

Explanation of symbols

  10 rasterizer, 30 shader unit, 32 register file, 34 drawing operation processing unit, 50 memory, 52 texture structure, 54 drawing data, 70 texture unit, 72 register file, 74 filter, 76 texture reading unit, 100 drawing processing device.

Claims (11)

A plurality of two-dimensional textures in which values relating to texture are stored as texel values in association with two-dimensional parameter coordinates are provided, and a third parameter for designating at least one of the plurality of two-dimensional textures is the two-dimensional parameter coordinates A texture storage unit for storing a texture structure provided separately from the first and second parameters;
The texture applied to the surface of the drawing object is designated by the third parameter and the two-dimensional parameter coordinate value on the surface, and corresponds to the designated third parameter in the texture structure. A texture reading unit that reads a texel value corresponding to the specified two-dimensional parameter coordinate value from the two-dimensional texture;
A filter that interpolates the read texel value and calculates a value related to the texture applied to the surface of the drawing object,
By specifying a value according to the relationship between the plurality of two-dimensional textures included in the texture structure as the third parameter, the different types of the texture structures are referred to uniformly. Characteristic texture processing apparatus.   2. The texture structure according to claim 1, wherein the texture structure has a layer structure in which two-dimensional textures defined in units of layers are provided for the number of layers, and the third parameter is a number for designating the layer. The texture processing apparatus described.   2. The texture structure according to claim 1, wherein the texture structure has a volume texture structure in which a plurality of two-dimensional textures having different depth levels are arranged in the depth direction, and the third parameter is a parameter related to the depth. Texture processing equipment. The texture reading unit selects two-dimensional textures having two different depth levels corresponding to the depth-related parameter designated as the third parameter, and designates each of the selected two-dimensional textures having two different depth levels. Read out the texel value corresponding to the two-dimensional parameter coordinates,
The said filter calculates the value regarding the texture applied to the surface of the said drawing target object by interpolating the said texel value between the two-dimensional textures of the said two different depth levels, The value of Claim 3 characterized by the above-mentioned. The texture processing apparatus described.   The texture structure has a structure in which the number of the environmental textures projected on the surface of the cube virtually provided in the space where the drawing target exists is provided, and the third parameter is the surface The texture processing apparatus according to claim 1, wherein the texture processing apparatus is a number that specifies A register for storing a base address for collectively referring to the texture structure;
The texture reading unit adds an offset value depending on the designated third parameter to the base address stored in the register, thereby obtaining the two-dimensional texture corresponding to the designated third parameter. 6. The texture processing apparatus according to claim 1, wherein a reference address is generated, and a texel value corresponding to a designated two-dimensional parameter coordinate value is read out based on the reference address. Each of the plurality of two-dimensional textures included in the texture structure is a set of mipmap textures having different resolutions in stages.
The texture reading unit also receives designation of the drawing detail level of the texture applied to the surface of the drawing object, and the designated drawing detail level of the set of mipmap textures corresponding to the designated third parameter 7. The mipmap texture having a resolution corresponding to 1 is selected, and the texel value corresponding to the designated two-dimensional parameter coordinate value is read from the selected mipmap texture. The texture processing apparatus described. The texture reading unit selects two different resolution mipmap textures corresponding to the specified drawing detail level from the set of mipmap textures corresponding to the specified third parameter, and selects the selected two Read out the texel values corresponding to the specified two-dimensional parameter coordinate values from each of the mipmap textures of different resolutions,
The said filter calculates the value regarding the texture applied to the surface of the said drawing target object by interpolating the said texel value between the said two mipmap textures of different resolution. Texture processing equipment. A plurality of two-dimensional textures in which values relating to texture are stored as texel values in association with two-dimensional parameter coordinates are provided, and a third parameter for designating at least one of the plurality of two-dimensional textures is the two-dimensional parameter coordinates A texture storage unit for storing a texture structure for storing a texture structure provided separately from the first and second parameters;
The texture applied to the surface of the drawing object is designated by the third parameter and the two-dimensional parameter coordinate value on the surface, and corresponds to the designated third parameter in the texture structure. A texture processing unit that reads out a texel value corresponding to the specified two-dimensional parameter coordinate value from the two-dimensional texture, and calculates an interpolation value related to the texture applied to the surface of the drawing target;
A drawing processing unit that performs drawing calculation processing of the drawing target using an interpolation value related to the texture output from the texture processing unit;
The texture structure has a structure in which only the number of environmental textures projected on a cube surface virtually provided in the space where the drawing target exists is provided,
The drawing processing unit obtains the surface number of the environmental texture mapped to the surface and the two-dimensional parameter coordinate value in the surface based on the reflection vector of the surface of the drawing object, The third parameter is specified to the texture processing unit together with the two-dimensional parameter coordinate value,
The texture processing unit includes the two-dimensional parameter coordinate value specified by the drawing processing unit from an environmental texture corresponding to the surface number specified as the third parameter by the drawing processing unit in the texture structure. The drawing processing apparatus is characterized in that the texel value corresponding to is read and an interpolation value related to the texture applied to the surface of the drawing object is calculated.   A plurality of two-dimensional textures in which values relating to the texture are stored as texel values in association with the two-dimensional parameter coordinates are provided, and a third parameter for designating at least one of the plurality of two-dimensional textures is the two-dimensional parameter coordinates The two-dimensional structure having a structure provided separately from the first and second parameters, and corresponding to the designated third parameter by a texture read command designating the two-dimensional parameter coordinate value and the third parameter Sampling of the texel value corresponding to the specified two-dimensional parameter coordinate value is possible from a texture, and the third parameter corresponds to the relationship between the plurality of two-dimensional textures included in the structure. Specified values, the uniform participation of different types of structures Data structure of the texture, characterized in that is configured to be. A plurality of two-dimensional textures in which values relating to texture are stored as texel values in association with two-dimensional parameter coordinates are provided, and a third parameter for designating at least one of the plurality of two-dimensional textures is the two-dimensional parameter coordinates For a texture memory holding a texture structure provided separately from the first and second parameters, the third parameter and the two-dimensional parameter coordinate values on the surface are applied to the texture applied to the surface of the drawing object. Sampling a texel value corresponding to the specified two-dimensional parameter coordinate value from the two-dimensional texture corresponding to the specified third parameter by executing a specified texture read command;
Interpolating the sampled texel values to calculate a value relating to a texture applied to the surface of the drawing object;
By specifying a value according to the relationship between the plurality of two-dimensional textures included in the texture structure as the third parameter, the different types of the texture structures are referred to uniformly. A characteristic texture processing method.

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