Provided by: opengl-4-man-doc_1.0~svn33624-1_all 
NAME
glGetTexLevelParameter - return texture parameter values for a specific level of detail
C SPECIFICATION
void glGetTexLevelParameterfv(GLenum target, GLint level, GLenum pname, GLfloat * params);
void glGetTexLevelParameteriv(GLenum target, GLint level, GLenum pname, GLint * params);
void glGetTextureLevelParameterfv(GLuint texture, GLint level, GLenum pname,
GLfloat *params);
void glGetTextureLevelParameteriv(GLuint texture, GLint level, GLenum pname,
GLint *params);
PARAMETERS
target
Specifies the target to which the texture is bound for glGetTexLevelParameterfv and
glGetTexLevelParameteriv functions. Must be one of the following values:
GL_TEXTURE_1D, GL_TEXTURE_2D, GL_TEXTURE_3D, GL_TEXTURE_1D_ARRAY, GL_TEXTURE_2D_ARRAY,
GL_TEXTURE_RECTANGLE, GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_2D_MULTISAMPLE_ARRAY,
GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_NEGATIVE_X,
GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y,
GL_TEXTURE_CUBE_MAP_POSITIVE_Z, GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, GL_PROXY_TEXTURE_1D,
GL_PROXY_TEXTURE_2D, GL_PROXY_TEXTURE_3D, GL_PROXY_TEXTURE_1D_ARRAY,
GL_PROXY_TEXTURE_2D_ARRAY, GL_PROXY_TEXTURE_RECTANGLE,
GL_PROXY_TEXTURE_2D_MULTISAMPLE, GL_PROXY_TEXTURE_2D_MULTISAMPLE_ARRAY,
GL_PROXY_TEXTURE_CUBE_MAP, or GL_TEXTURE_BUFFER.
texture
Specifies the texture object name for glGetTextureLevelParameterfv and
glGetTextureLevelParameteriv functions.
level
Specifies the level-of-detail number of the desired image. Level 0 is the base image
level. Level n is the nth mipmap reduction image.
pname
Specifies the symbolic name of a texture parameter. GL_TEXTURE_WIDTH,
GL_TEXTURE_HEIGHT, GL_TEXTURE_DEPTH, GL_TEXTURE_INTERNAL_FORMAT, GL_TEXTURE_RED_SIZE,
GL_TEXTURE_GREEN_SIZE, GL_TEXTURE_BLUE_SIZE, GL_TEXTURE_ALPHA_SIZE,
GL_TEXTURE_DEPTH_SIZE, GL_TEXTURE_COMPRESSED, GL_TEXTURE_COMPRESSED_IMAGE_SIZE, and
GL_TEXTURE_BUFFER_OFFSET are accepted.
params
Returns the requested data.
DESCRIPTION
glGetTexLevelParameterfv, glGetTexLevelParameteriv, glGetTextureLevelParameterfv and
glGetTextureLevelParameteriv return in params texture parameter values for a specific
level-of-detail value, specified as level. For the first two functions, target defines the
target texture, either GL_TEXTURE_1D, GL_TEXTURE_2D, GL_TEXTURE_3D, GL_PROXY_TEXTURE_1D,
GL_PROXY_TEXTURE_2D, GL_PROXY_TEXTURE_3D, GL_TEXTURE_CUBE_MAP_POSITIVE_X,
GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y,
GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z,
GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, or GL_PROXY_TEXTURE_CUBE_MAP. The remaining two take a
texture argument which specifies the name of the texture object.
GL_MAX_TEXTURE_SIZE, and GL_MAX_3D_TEXTURE_SIZE are not really descriptive enough. It has
to report the largest square texture image that can be accommodated with mipmaps but a
long skinny texture, or a texture without mipmaps may easily fit in texture memory. The
proxy targets allow the user to more accurately query whether the GL can accommodate a
texture of a given configuration. If the texture cannot be accommodated, the texture state
variables, which may be queried with glGetTexLevelParameter and
glGetTextureLevelParameter, are set to 0. If the texture can be accommodated, the texture
state values will be set as they would be set for a non-proxy target.
pname specifies the texture parameter whose value or values will be returned.
The accepted parameter names are as follows:
GL_TEXTURE_WIDTH
params returns a single value, the width of the texture image. The initial value is 0.
GL_TEXTURE_HEIGHT
params returns a single value, the height of the texture image. The initial value is
0.
GL_TEXTURE_DEPTH
params returns a single value, the depth of the texture image. The initial value is 0.
GL_TEXTURE_INTERNAL_FORMAT
params returns a single value, the internal format of the texture image.
GL_TEXTURE_RED_TYPE, GL_TEXTURE_GREEN_TYPE, GL_TEXTURE_BLUE_TYPE, GL_TEXTURE_ALPHA_TYPE,
GL_TEXTURE_DEPTH_TYPE
The data type used to store the component. The types GL_NONE, GL_SIGNED_NORMALIZED,
GL_UNSIGNED_NORMALIZED, GL_FLOAT, GL_INT, and GL_UNSIGNED_INT may be returned to
indicate signed normalized fixed-point, unsigned normalized fixed-point,
floating-point, integer unnormalized, and unsigned integer unnormalized components,
respectively.
GL_TEXTURE_RED_SIZE, GL_TEXTURE_GREEN_SIZE, GL_TEXTURE_BLUE_SIZE, GL_TEXTURE_ALPHA_SIZE,
GL_TEXTURE_DEPTH_SIZE
The internal storage resolution of an individual component. The resolution chosen by
the GL will be a close match for the resolution requested by the user with the
component argument of glTexImage1D(), glTexImage2D(), glTexImage3D(),
glCopyTexImage1D(), and glCopyTexImage2D(). The initial value is 0.
GL_TEXTURE_COMPRESSED
params returns a single boolean value indicating if the texture image is stored in a
compressed internal format. The initiali value is GL_FALSE.
GL_TEXTURE_COMPRESSED_IMAGE_SIZE
params returns a single integer value, the number of unsigned bytes of the compressed
texture image that would be returned from glGetCompressedTexImage().
GL_TEXTURE_BUFFER_OFFSET
params returns a single integer value, the offset into the data store of the buffer
bound to a buffer texture. glTexBufferRange().
GL_TEXTURE_BUFFER_SIZE
params returns a single integer value, the size of the range of a data store of the
buffer bound to a buffer texture. glTexBufferRange().
NOTES
If an error is generated, no change is made to the contents of params.
glGetTexLevelParameter returns the texture level parameters for the active texture unit.
GL_TEXTURE_BUFFER_OFFSET and GL_TEXTURE_BUFFER_SIZE are available only if the GL version
is 4.3 or greater.
ERRORS
GL_INVALID_OPERATION is generated by glGetTextureLevelParameterfv and
glGetTextureLevelParameteriv functions if texture is not the name of an existing texture
object.
GL_INVALID_ENUM is generated by glGetTexLevelParameterfv and glGetTexLevelParameteriv
functions if target or pname is not an accepted value.
GL_INVALID_VALUE is generated if level is less than 0.
GL_INVALID_VALUE may be generated if level is greater than log 2 max, where max is the
returned value of GL_MAX_TEXTURE_SIZE.
GL_INVALID_VALUE is generated if target is GL_TEXTURE_BUFFER and level is not zero.
GL_INVALID_OPERATION is generated if GL_TEXTURE_COMPRESSED_IMAGE_SIZE is queried on
texture images with an uncompressed internal format or on proxy targets.
VERSION SUPPORT
┌─────────────────────────────┬───────────────────────────────────────────────────────────────────────┐
│ │ OpenGL Version │
├─────────────────────────────┼─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┤
│Function │ 2.0 │ 2.1 │ 3.0 │ 3.1 │ 3.2 │ 3.3 │ 4.0 │ 4.1 │ 4.2 │ 4.3 │ 4.4 │ 4.5 │
│/ │ │ │ │ │ │ │ │ │ │ │ │ │
│Feature │ │ │ │ │ │ │ │ │ │ │ │ │
│Name │ │ │ │ │ │ │ │ │ │ │ │ │
├─────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│glGetTexLevelParameterfv │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │
├─────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│glGetTexLevelParameteriv │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │ ✔ │
├─────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│glGetTextureLevelParameterfv │ - │ - │ - │ - │ - │ - │ - │ - │ - │ - │ - │ ✔ │
├─────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│glGetTextureLevelParameteriv │ - │ - │ - │ - │ - │ - │ - │ - │ - │ - │ - │ ✔ │
└─────────────────────────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘
SEE ALSO
glActiveTexture(), glGetTexParameter(), glCopyTexImage1D(), glCopyTexImage2D(),
glCopyTexSubImage1D(), glCopyTexSubImage2D(), glCopyTexSubImage3D(), glTexImage1D(),
glTexImage2D(), glTexImage3D(), glTexSubImage1D(), glTexSubImage2D(), glTexSubImage3D(),
glTexParameter()
COPYRIGHT
Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2010-2014 Khronos Group. This
document is licensed under the SGI Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.
COPYRIGHT
Copyright © 2014 Khronos Group
[FIXME: source] 01/03/2018 GLGETTEXLEVELPARAMET(3G)