void GLAPIENTRY glTexParameterf( GLenum target,
GLenum pname,
GLfloat param )
void GLAPIENTRY glTexParameteri( GLenum target,
GLenum pname,
GLint param )
PARAMETERS
target Specifies the target texture, which must be either
GL_TEXTURE_1D, GL_TEXTURE_2D, or GL_TEXTURE_3D.
pname Specifies the symbolic name of a single-valued texture parame‐
ter. pname can be one of the following: GL_TEXTURE_MIN_FILTER,
GL_TEXTURE_MAG_FILTER, GL_TEXTURE_MIN_LOD, GL_TEXTURE_MAX_LOD,
GL_TEXTURE_BASE_LEVEL, GL_TEXTURE_MAX_LEVEL, GL_TEXTURE_WRAP_S,
GL_TEXTURE_WRAP_T, GL_TEXTURE_WRAP_R, or GL_TEXTURE_PRIORITY.
param Specifies the value of pname.
C SPECIFICATION
void GLAPIENTRY glTexParameterfv( GLenum target,
GLenum pnam )
void GLAPIENTRY glTexParameteriv( GLenum target,
GLenum pnam )
PARAMETERS
target Specifies the target texture, which must be either GL_TEXTURE_1D,
GL_TEXTURE_2D or GL_TEXTURE_3D.
pnam Specifies the symbolic name of a texture parameter. pnam can be
one of the following: GL_TEXTURE_MIN_FILTER,
GL_TEXTURE_MAG_FILTER, GL_TEXTURE_MIN_LOD, GL_TEXTURE_MAX_LOD,
GL_TEXTURE_BASE_LEVEL, GL_TEXTURE_MAX_LEVEL, GL_TEXTURE_WRAP_S,
GL_TEXTURE_WRAP_T, GL_TEXTURE_WRAP_R, GL_TEXTURE_BORDER_COLOR, or
GL_TEXTURE_PRIORITY.
Specifies a pointer to an array where the value or values of pnam
are stored.
DESCRIPTION
Texture mapping is a technique that applies an image onto an object's
surface as if the image were a decal or cellophane shrink-wrap. The im‐
age is created in texture space, with an (s, t) coordinate system. A
texture is a one- or two-dimensional image and a set of parameters that
determine how samples are derived from the image.
glTexParameter assigns the value or values in to the texture parameter
specified as pnam. target defines the target texture, either
GL_TEXTURE_1D, GL_TEXTURE_2D, or GL_TEXTURE_3D. The following symbols
are accepted in pnam:
GL_TEXTURE_MIN_FILTER
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.
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 el‐
ements 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 aver‐
age of those two values.
As more texture elements are sampled in the minification
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 el‐
ements 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_BASE_LEVEL
Specifies the index of the lowest defined mipmap level. This
is an integer value. The initial value is 0.
GL_TEXTURE_MAX_LEVEL
Sets the index of the highest defined mipmap level. This is an
integer value. The initial value is 1000.
GL_TEXTURE_WRAP_S
Sets the wrap parameter for texture coordinate s to either
GL_CLAMP, GL_CLAMP_TO_EDGE, or GL_REPEAT. GL_CLAMP causes s
coordinates to be clamped to the range [0,1] and is useful for
preventing wrapping artifacts when mapping a single image onto
an object. GL_CLAMP_TO_EDGE causes s coordinates to be
clamped to the range ⎣__,1−__⎦, 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 pat‐
tern. Border texture elements are accessed only if wrapping
is set to GL_CLAMP. 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, GL_CLAMP_TO_EDGE, or GL_REPEAT. See the discussion
under GL_TEXTURE_WRAP_S. Initially, GL_TEXTURE_WRAP_T is set
the range [0,1] when they are specified. Initially, the bor‐
der color is (0, 0, 0, 0).
GL_TEXTURE_PRIORITY
Specifies the texture residence priority of the currently
bound texture. Permissible values are in the range [0, 1].
See glPrioritizeTextures and glBindTexture for more informa‐
tion.
NOTES
GL_TEXTURE_3D, GL_TEXTURE_MIN_LOD, GL_TEXTURE_MAX_LOD,
GL_TEXTURE_BASE_LEVEL, and GL_TEXTURE_MAX_LEVEL are only available if
the GL version is 1.2 or greater.
Suppose that a program has enabled texturing (by calling glEnable with
argument GL_TEXTURE_1D, GL_TEXTURE_2D, or GL_TEXTURE_3D) and has set
GL_TEXTURE_MIN_FILTER to one of the functions that requires a mipmap.
If either the dimensions of the texture images currently defined (with
previous calls to glTexImage1D, glTexImage2D, glTexImage3D,
glCopyTexImage1D, or glCopyTexImage2D) do not follow the proper sequence
for mipmaps (described above), or there are fewer texture images defined
than are needed, or the set of texture images have differing numbers of
texture components, then it is as if texture mapping were disabled.
Linear filtering accesses the four nearest texture elements only in 2D
textures. In 1D textures, linear filtering accesses the two nearest
texture elements.
When the GL_ARB_multitexture extension is supported, glTexParameter
specifies the texture parameters for the active texture unit, specified
by calling glActiveTextureARB.
ERRORS
GL_INVALID_ENUM is generated if target or pnam is not one of the ac‐
cepted defined values.
GL_INVALID_ENUM is generated if should have a defined constant value
(based on the value of pnam) and does not.
GL_INVALID_OPERATION is generated if glTexParameter is executed between
the execution of glBegin and the corresponding execution of glEnd.
ASSOCIATED GETS
glGetTexParameter
glGetTexLevelParameter
SEE ALSO
glActiveTextureARB, glBindTexture, glCopyPixels, glCopyTexImage1D,
glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D,
glCopyTexSubImage3D, glDrawPixels, glPixelStore, glPixelTransfer,
glPrioritizeTextures, glTexEnv, glTexGen, glTexImage1D, glTexImage2D,
glTexImage3D, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D
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