# Template:Glapi sampler parameters

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GL_TEXTURE_MIN_FILTER
The texture minifying function is used whenever the pixel being textured maps to an area greater than one texture element. There are six defined minifying functions. Two of them use the nearest one or nearest four texture elements to compute the texture value. The other four use mipmaps.
A mipmap is an ordered set of arrays representing the same image at progressively lower resolutions. If the texture has dimensions 2n × 2m, there are max(n, m) + 1 mipmaps. The first mipmap is the original texture, with dimensions 2n × 2m. Each subsequent mipmap has dimensions 2k - 1 × 2l - 1, where 2k × 2l are the dimensions of the previous mipmap, until either k or l. At that point, subsequent mipmaps have dimension 1 × 2l - 1 or 2k - 1 × 1 until the final mipmap, which has dimension 1 × 1. To define the mipmaps, call glTexImage1D, glTexImage2D, glTexImage3D, glCopyTexImage1D, or glCopyTexImage2D with the level argument indicating the order of the mipmaps. Level 0 is the original texture; level max(n, m) is the final 1 × 1 mipmap.
params supplies a function for minifying the texture as one of the following:
 GL_NEAREST Returns the value of the texture element that is nearest (in Manhattan distance) to the center of the pixel being textured. GL_LINEAR Returns the weighted average of the four texture elements that are closest to the center of the pixel being textured. These can include border texture elements, depending on the values of GL_TEXTURE_WRAP_S and GL_TEXTURE_WRAP_T, and on the exact mapping. GL_NEAREST_MIPMAP_NEAREST Chooses the mipmap that most closely matches the size of the pixel being textured and uses the GL_NEAREST criterion (the texture element nearest to the center of the pixel) to produce a texture value. GL_LINEAR_MIPMAP_NEAREST Chooses the mipmap that most closely matches the size of the pixel being textured and uses the GL_LINEAR criterion (a weighted average of the four texture elements that are closest to the center of the pixel) to produce a texture value. GL_NEAREST_MIPMAP_LINEAR Chooses the two mipmaps that most closely match the size of the pixel being textured and uses the GL_NEAREST criterion (the texture element nearest to the center of the pixel) to produce a texture value from each mipmap. The final texture value is a weighted average of those two values. GL_LINEAR_MIPMAP_LINEAR Chooses the two mipmaps that most closely match the size of the pixel being textured and uses the GL_LINEAR criterion (a weighted average of the four texture elements that are closest to the center of the pixel) to produce a texture value from each mipmap. The final texture value is a weighted average of those two values.
As more texture elements are sampled in the minification process, fewer aliasing artifacts will be apparent. While the GL_NEAREST and GL_LINEAR minification functions can be faster than the other four, they sample only one or four texture elements to determine the texture value of the pixel being rendered and can produce moire patterns or ragged transitions. The initial value of GL_TEXTURE_MIN_FILTER is GL_NEAREST_MIPMAP_LINEAR.
GL_TEXTURE_MAG_FILTER
The texture magnification function is used when the pixel being textured maps to an area less than or equal to one texture element. It sets the texture magnification function to either GL_NEAREST or GL_LINEAR (see below). GL_NEAREST is generally faster than GL_LINEAR, but it can produce textured images with sharper edges because the transition between texture elements is not as smooth. The initial value of GL_TEXTURE_MAG_FILTER is GL_LINEAR.
 GL_NEAREST Returns the value of the texture element that is nearest (in Manhattan distance) to the center of the pixel being textured. GL_LINEAR Returns the weighted average of the four texture elements that are closest to the center of the pixel being textured. These can include border texture elements, depending on the values of GL_TEXTURE_WRAP_S and GL_TEXTURE_WRAP_T, and on the exact mapping.
GL_TEXTURE_MIN_LOD
Sets the minimum level-of-detail parameter. This floating-point value limits the selection of highest resolution mipmap (lowest mipmap level). The initial value is -1000.
GL_TEXTURE_MAX_LOD
Sets the maximum level-of-detail parameter. This floating-point value limits the selection of the lowest resolution mipmap (highest mipmap level). The initial value is 1000.
GL_TEXTURE_WRAP_S
Sets the wrap parameter for texture coordinate s to either GL_CLAMP_TO_BORDER, GL_CLAMP_TO_EDGE, GL_MIRRORED_REPEAT, or GL_REPEAT. GL_CLAMP_TO_BORDER causes the s coordinate to be clamped to the range ${\displaystyle \left[{\tfrac {-1}{2N}},1+{\tfrac {1}{2N}}\right]}$, where N is the size of the texture in the direction of clamping. GL_CLAMP_TO_EDGE causes s coordinates to be clamped to the range ${\displaystyle \left[{\tfrac {1}{2N}},1-{\tfrac {1}{2N}}\right]}$, where N is the size of the texture in the direction of clamping. GL_REPEAT causes the integer part of the s coordinate to be ignored; the GL uses only the fractional part, thereby creating a repeating pattern. GL_MIRRORED_REPEAT causes the s coordinate to be set to the fractional part of the texture coordinate if the integer part of s is even; if the integer part of s is odd, then the s texture coordinate is set to 1 - frac(s), where frac(s) represents the fractional part of s. Initially, GL_TEXTURE_WRAP_S is set to GL_REPEAT.
GL_TEXTURE_WRAP_T
Sets the wrap parameter for texture coordinate t to either GL_CLAMP_TO_BORDER, GL_CLAMP_TO_EDGE, GL_MIRRORED_REPEAT, or GL_REPEAT. See the discussion under GL_TEXTURE_WRAP_S. Initially, GL_TEXTURE_WRAP_T is set to GL_REPEAT.
GL_TEXTURE_WRAP_R
Sets the wrap parameter for texture coordinate r to either GL_CLAMP_TO_BORDER, GL_CLAMP_TO_EDGE, GL_MIRRORED_REPEAT, or GL_REPEAT. See the discussion under GL_TEXTURE_WRAP_S. Initially, GL_TEXTURE_WRAP_R is set to GL_REPEAT.
GL_TEXTURE_BORDER_COLOR
The data in params specifies four values that define the border values that should be used for border texels. If a texel is sampled from the border of the texture, the values of GL_TEXTURE_BORDER_COLOR are interpreted as an RGBA color to match the texture's internal format and substituted for the non-existent texel data. If the texture contains depth components, the first component of GL_TEXTURE_BORDER_COLOR is interpreted as a depth value. The initial value is (0.0, 0.0, 0.0, 0.0).
GL_TEXTURE_COMPARE_MODE
Specifies the texture comparison mode for currently bound textures. That is, a texture whose internal format is GL_DEPTH_COMPONENT_*; see glTexImage2D) Permissible values are:
 GL_COMPARE_REF_TO_TEXTURE Specifies that the interpolated and clamped r texture coordinate should be compared to the value in the currently bound texture. See the discussion of GL_TEXTURE_COMPARE_FUNC for details of how the comparison is evaluated. The result of the comparison is assigned to the red channel. GL_NONE Specifies that the red channel should be assigned the appropriate value from the currently bound texture.
GL_TEXTURE_COMPARE_FUNC
Specifies the comparison operator used when GL_TEXTURE_COMPARE_MODE is set to GL_COMPARE_REF_TO_TEXTURE. Permissible values are:
Texture Comparison Function Computed result
GL_LEQUAL ${\displaystyle result={\begin{cases}1.0,&r\leq D_{t}\\0.0,&r>D_{t}\end{cases}}}$
GL_GEQUAL ${\displaystyle result={\begin{cases}1.0,&r\geq D_{t}\\0.0,&r
GL_LESS ${\displaystyle result={\begin{cases}1.0,&r
GL_GREATER ${\displaystyle result={\begin{cases}1.0,&r>D_{t}\\0.0,&r\leq D_{t}\end{cases}}}$
GL_EQUAL ${\displaystyle result={\begin{cases}1.0,&r=D_{t}\\0.0,&r\neq D_{t}\end{cases}}}$
GL_NOTEQUAL ${\displaystyle result={\begin{cases}1.0,&r\neq D_{t}\\0.0,&r=D_{t}\end{cases}}}$
GL_ALWAYS ${\displaystyle result=1.0}$
GL_NEVER ${\displaystyle result=0.0}$

where r is the current interpolated texture coordinate, and Dt is the texture value sampled from the currently bound texture. result is assigned to Rt.