KR0132826B1 - Texture address generator - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to computer graphics and, more particularly, to a texture address generator that performs texture mapping. The apparatus according to the present invention is a texture address generator for texture mapping, comprising: an interpolator for specifying the addresses of texture addresses U and V of pixels on edges having the lowest and highest values in the y-direction in the flickr. edge interpolator); And an X interpolator for specifying the addresses of texture addresses U and V corresponding to each pixel in the plygun while interpolating the output value of the edge interpolator in the x direction along the scan line. Include.

The effect of the present invention is that the texture address parameter can be set to perform texture mapping inside the polygon in two ways, thereby reducing the amount of computation of data and enabling high-speed processing.

Description

Texture Address Generator for Texture Mapping

1 is a view for explaining a conventional technique of mapping the inside of one plygun.

2 is a view for explaining the present invention to map the inside of one plygun.

FIG. 3A shows the texture address parameter for the texture address parameter U inside the flickr.

3B shows the texture address parameter for the texture address parameter V inside the flickr.

4 is a detailed view of the edge interpolator.

5 is a detailed view of the X interpolator.

FIG. 6 is a diagram for explaining the flow of register values in tracing in the x-direction and y-direction during tracing of the inside of the plygun to designate a texture address parameter.

TECHNICAL FIELD The present invention relates to computer graphics, and more particularly, to a texture address generator that performs texture mapping.

Texture mapping is a graphics function used to generate photo-realistic images. It is a function of coating a two-dimensional image onto a three-dimensional object surface. In other words, if you want to make the wall made of blocks vividly, you can do it by mapping the block wall image (texture image) to a large rectangle.

In general, in performing image mapping, a polygon is conventionally cut in a geometry engine (hereinafter, referred to as GE) in span units corresponding to scanlines, and texture addresses U and V for each span are used. After obtaining the quadratic equation of, we calculate the texture parameters. The rasterization engine (hereinafter referred to as RE) receives these data and performs second-order interpolation to generate U and V addresses, and then reads the corresponding color values from the texture memory where the texture image is stored in the frame buffer. Update This prior art has to be calculated for each span. This is because the amount of data between GE and RE is relatively large, and there is a problem of the amount of computation required and the speed and cost of texture mapping. Thus, there is a need for an alternative that can improve this.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device for designating a texture address inside a polygon with one texture address U and V equations for one pulley gun.

An apparatus according to the present invention for achieving the above object, in the texture address generator for texture mapping of the texture address U and V of the pixels on the edge having the lowest and highest values in the y direction in the polygon Edge interpolator for addressing; And an X interpolator for specifying an address of texture addresses U and V corresponding to each pixel in the polygon while interpolating the output value of the edge interpolator in the x direction along the scan line. do.

Hereinafter, the present invention will be described in detail with reference to the drawings. Prior art will be described in order to correctly understand the present invention.

1 is a view for explaining a conventional technique for mapping the inside of one polygon. In FIG. 1, quadratic equations and parameters for texture addresses U and V are obtained for spans spanning a scan line passing through one polygon. If this is expressed as an expression, it is as follows.

F ₁ (x) = A ₁ X ² + B ₁ X + C ₁ [Equation 1]

F ₂ (x) = A ₂ X ² + B ₂ X + C ₂ [Equation 2]

F ₃ (x) = A ₃ X ² + B ₃ X + C ₃ [Equation 3]

F ₄ (x) = A ₄ X ² + B ₄ X + C ₄ [Equation 4]

F ₅ (x) = A ₅ X ² + B ₅ X + C ₅ [Equation 5]

[Equation 1] is a formula for designating a texture address parameter corresponding to the span passing through the first scan line in FIG. [Equation 2] is a formula for designating a texture address parameter corresponding to the span passing through the second scan line in FIG. Equation 3 specifies a texture address parameter corresponding to the span passing through the third scan line. Equation 4 specifies a texture address parameter corresponding to the span passing through the fourth scan line. Equation 5 specifies a texture address parameter corresponding to a span passing through the fifth scan line. In the example above, five spans are assigned to one polygon to perform texture mapping, but this can be any amount. That is, more and more spans are required to perform relatively finer and more dense texture mapping. Also, more spans require more computation and more data. It is obvious that this can have a huge impact on throughput. There is then a need for an ultimate alternative to the speed of graphics, which rejects this conventional method and ameliorates the above conventional problem. Then, the present invention according to the above requirements will be described. First, FIG. 2 is introduced for easy contrast with the prior art.

2 is a view for explaining the present invention to map the inside of one polygon. Unlike the conventional texture address parameter specification in which the number of spans is determined according to the mapping density inside the polygon and the number of formulas specifying texture address parameters proportional to the number of spans is determined in the present invention, two equations are used in the present invention. To address a polygon, you specify an address. First, the following formula will be introduced.

F _u (x, y) = A ₁ X ² + B ₁ Y ² + C ₁ XY + D ₁ X + E ₁ Y + F ₁ [Equation 6]

F _v (x, y) = A ₂ X ² + B ₂ Y ² + C ₂ XY + D ₂ X + E ₂ Y + F ₂ [Equation 7]

Texture Address Parameter Values for U

X ″: d / dx (dF _u (x, y) / dx)

Y ″: d / dy (dF _u (x, y) / dy)

X'Y ': d / dx (dF _u (x, y) / dy) or d / dy (dF _u (x, y) / dx)

X ′: dF _u (x, y) / dx)

Y ′: dF _u (x, y) / dy)

U: F _u (x, y)

Texture Address Parameter Values for * V

X ″: d / dx (dF _v (x, y) / dx)

Y ″: d / dy (dF _v (x, y) / dy)

X′Y ′: d / dx (dF _v (x, y) / dy) or d / dy (dF _v (x, y) / dx)

X ′: dF _v (x, y) / dx)

Y ′: dF _v (x, y) / dy)

U: F _v (x, y)

The U and V values are the texture address parameter values inside the polygon as mentioned above. The above-described equations will be explained in conjunction with the drawings shown later.

3A and 3B are an overall circuit diagram according to the present invention. FIG. 3A shows the texture address parameter for the texture address parameter U inside the polygon, and FIG. 3B shows the texture address parameter for the texture address parameter V inside the polygon. In Fig. 3A, reference numeral 10 denotes an edge interpolator and 12 denotes an X interpolator. The same applies to FIG. 3B. Since the operation of the texture address parameters U and V is the same, only the texture address parameter U will be described in consideration of simplicity. First, texture address parameter values calculated at GE (not shown) are stored in registers in the edge interpolator 10 and the X interpolator 12. The edge interpolator 10 is dedicated to finding the U and V addresses of the pixels on the edge connecting the two end points (hereinafter referred to as vertices) having the lowest and highest values for the y direction in the polygon shown in FIG. do. Interpolate in the x and y directions along the edge by using the edge function as the starting point of the y axis. Next, a detailed view of the edge interpolator 10 and the X interpolator 12 of FIGS. 3A and 3B will be described.

4 is a detailed view of the edge interpolator. In Fig. 4, reference numeral 20 is X ″ first register, 22 is X′Y ′ second register, 24 is Y ″ third register, 26 is X ′ fourth register, 28 is Y ′ 5th register, 30 is the 6th register which is a texture address parameter U, 32 is the 1st signal which selects and outputs one of two values using the initial value of X 'and the value of the said 4th register 26 as an input element. 34 is a second signal selector which selects and outputs one of two values using the values of the first register 20 and the second register 22 as input elements, and 36 denotes the first register. 22) and a third signal selector which selects and outputs one of two values using the values of the third register 24 as an input element, and 38 denotes an initial value of Y ′ and a value of the fifth register 28. A fourth signal selector which selects and outputs one of two values as an input element, and 40 denotes the first signal; A first adder / subtracter using the signal selector 32 and the second signal selector 34 as input elements, and 42 denotes the third signal selector 36 and the fourth signal selector 38. Is a second subtractor having the value of as an input element, and 44 denotes a second subtractor which selects and outputs one of two values using the values of the first adder / subtracter 40 and the second subtractor 42 as input elements. 5 is a signal selector, and 46 is a sixth signal selector for selecting and outputting one of two values using the initial value of the texture address parameter U and the value of the sixth register as input elements, and 48 is the fifth signal selector. A third adder / subtracter uses the values of 44 and the sixth signal selector 46 as input elements. Finally, the constant U value output from the sixth register 30 and the value X ′ output from the fourth register 26 become an output element of the edge interpolator. These values are the input elements of the X interpolator, which we will introduce next.

So far, reference numerals have been described in FIG. 4 of the edge interpolator. Prior to describing the operation of the edge interpolator, the X interpolator is introduced and then described in connection with both.

5 is a detailed view of the X interpolator. In FIG. 5, reference numeral 50 is a seventh signal selector that uses X ′ value, which is an output element of the edge interpolator, and X ′ value generated through another process to be described later, and 52 is X ″. A seventh register, 54 is a fourth adder / subtractor that uses the values of the seventh signal selector 50 and the seventh register 52 as input elements, and 56 is the fourth adder / subtractor 54 Is an input element of the seventh signal selection unit 50 and an input element of X ′ which is an input element of the fifth addition / subtraction unit, which will be described later, and 58 is an output element of the edge interpolator. The eighth signal selection unit having a value and a U value to be described later as an input element, and 60 denotes an output element of the fourth adding / subtracting unit 54 and an output value of the eighth signal selecting unit 58. A fifth adding / subtracting section, and 62 is a U ninth register having an output value of the fourth adding / subtracting section 54, which is It is also an input element of the eighth register 58 and finally a value that indexes a texture memory (not shown).

So far, the detailed diagrams of the edge interpolator and the X interpolator constituting the texture address (U) generator, which is the overall circuit diagram of the present invention, have been introduced. As described above, only the texture address parameter U is referred to, and the description of the texture address parameter V is omitted for the same reason as the texture address parameter U described above.

Then, the process of performing the introduced edge interpolator and X interpolator will be described. The drawings will be briefly described in order to correctly understand the implementation thereof.

FIG. 6 is a diagram for explaining the flow of register values when tracking in the x direction and the y direction in the failure of tracking the inside of the polygon to designate a texture address parameter. In Fig. 6, reference numeral 70 is a register having a value of X ″, 72 is a register having a value of X′Y ′, 74 is a register having a value of Y ″, 76 is a register having a value of X ′, 78 is a register having a Y 'value, 80 is a register having a texture address parameter U and V values, and for the same reason as described above, the description of the U value will be limited. In addition, the dotted line in the figure relates to the y direction, and the solid line relates to the x direction. First, let's say that it moved in the x direction. This is a solid line. The X 'value 76 then updates to the X' 'value 70, the Y' value 78 updates to the X'Y '72, and the U value 80 changes to the X' value 76. Update. On the other hand, if it moved in the y direction, it corresponds to the dotted line. Y ′ value 78 updates to Y ″ value 74, X ′ value 76 updates to X′Y ′ value 72, and U value 80 to Y ′ value 78. Update. In this manner, the edge interpolator of FIG. 4 is performed.

Ultimately, in computer graphics, we start by mapping the texture mapping to a single polygon. In addition, in order to apply polygon color, it is necessary to determine how dense the color is to be colored. This is a matter of how much density you want to address inside the polygon. This is based on Equations 6 and 7 as described above. A ₁ , A ₂ , B ₁ , B ₂ , C ₁ , C ₂ , D ₁ , D ₂ , E ₁ , E ₂ , F ₁ , F ₂ , X and Y in [Formula 6] and [Formula 7] The value of is determined by how dense each address is inside the polygon. Then, see Figure 4.

When shifted in the negative y direction in FIG. 4, the value Y ′ stored in the fifth register 28 is subtracted by the value Y ″ stored in the third register 24 as described in FIG. 6. Update to the value of Y '. Here, the functions of the respective signal selector and the adder / subtracter are well known techniques, and thus description thereof is omitted for convenience of description. However, signal selection of the signal selection units is as described with reference to FIG. 6. In addition, the value stored in the fourth register 26 is updated to the value of X 'of the fourth register 26 by subtracting the value X' stored in the second register 22 by X'Y '. In addition, the value U stored in the sixth register 30 is subtracted by the value Y ′ stored in the fifth register 28 to update the fifth register 28. The current U value and X ', which are the final output values of the edge interpolator of FIG. 4, are sent to the X interpolator. On the other hand, when shifted in the positive x direction, the value Y 'stored in the fifth register 28 is added to the value X'Y' stored in the second register 22 to add the Y 'value of the fifth register 28. Update. The value X 'of the fourth register 26 is updated by adding the value X' stored in the fourth register 26 to the value X ″ stored in the first register 20. The value U stored in the sixth register 30 is added to the value X ′ stored in the fourth register 26 to update the U value of the sixth register 30.

In the negative x direction, the value Y 'stored in the fifth register 28 is subtracted from the value X'Y' stored in the second register 22, and the Y 'value of the fifth register 28 is subtracted. Update. The value X ′ of the fourth register 26 is updated by subtracting the value X ′ stored in the fourth register 26 by the value X ″ stored in the first register 20. The U value of the sixth register 30 is updated by subtracting the value U stored in the sixth register 30 by the value X ′ stored in the fourth register 26.

The X interpolator of FIG. 5 is responsible for obtaining a U texture address corresponding to each pixel while interpolating in the x direction along the scan line from the values X 'and U output from the edge interpolator. That is, the X 'variable is updated to X ″, and the U texture address value is output after the update to the newly updated X' and used as a column address of the texture memory. Let's look at the implementation of the X interpolator of FIG.

First, when shifted in the positive x direction, the value X 'stored in the eighth register 56 is added to the value X " stored in the seventh register 52 to update the X' value of the eighth register 56. FIG. In addition, the value U stored in the ninth register 62 is added to the value X 'stored in the eighth register 56 to update the U value of the ninth register 62 and output to the texture memory (not shown). On the other hand, when shifted in the negative x direction, the value X 'stored in the eighth register 56 is subtracted from X ″ stored in the seventh register 52 to update the X ′ value of the eighth register 56. Further, the value U stored in the ninth register 62 is subtracted by the value X 'stored in the eighth register 56 to update the U value of the ninth register 62 and output to the texture memory (not shown).

The present invention constructed as described above has the effect of enabling the high speed processing by reducing the amount of computation of data by setting the texture address parameter to perform texture mapping inside the pulley in two ways.

Claims (3)

A texture address generator for texture mapping, comprising: an edge interpolator for specifying the address of texture addresses U and V of pixels on an edge having the lowest and highest values in the y direction for a polygon; And an X interpolator for specifying an address of texture addresses U and V corresponding to each pixel in the polygon while interpolating the output value of the edge interpolator along the scan line along the scan line. Texture address generator. 2. The edge interpolator of claim 1, wherein an edge interpolator that specifies the addresses of the texture addresses U and V of the pixels on the edge having the lowest and highest values in the y direction for the polygon is in the negative y direction. When moving, Y 'value is updated to the value of Y' by subtracting Y ″ value, X 'value is updated to the value of X' by subtracting X'Y ', and U value and V value are subtracted by Y' value. When the value of V is updated, and when it moves in the positive x direction, the value of Y 'is updated by adding the value of Y' to the value of X'Y ', and the value of X' is added by adding the value of X 'to the value of X ″ to update the value of U and Update the U and V values by adding the V value to the X 'value, and update the Y' value by subtracting the Y 'value to the X'Y' value when moving in the negative x direction, and replacing the X 'value with the X ″ value. Update the value of X 'by subtracting and update the value of U and V by subtracting the value of U and V by the value of X Texture address generator comprising a U value and a ejwi interpolator (Edge interpolator), characterized by sending a value V and X 'in the X interpolator. The X interpolator of claim 1, wherein the X interpolator specifies an address of texture addresses U and V corresponding to each pixel in the polygon while interpolating the output value of the edge interpolator in the x direction along the scan line. (x interpolator) updates the value of X 'by adding X' to X ″ and updates the U and V values by adding U and V to X 'when moving in the positive x direction, negative x When moving in the direction, update X value by subtracting X 'value by X ″, update U value and V value by subtracting U value and V value by X', and send the final output values U and V to texture memory. A texture address generator comprising an X interpolator.