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GLGETTEXLEVELPARAMET(3G)                         OpenGL 3.3                         GLGETTEXLEVELPARAMET(3G)



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);

PARAMETERS
       target
           Specifies the symbolic name of the target texture, one of 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.

       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_BORDER, GL_TEXTURE_RED_SIZE,
           GL_TEXTURE_GREEN_SIZE, GL_TEXTURE_BLUE_SIZE, GL_TEXTURE_ALPHA_SIZE, GL_TEXTURE_DEPTH_SIZE,
           GL_TEXTURE_COMPRESSED, and GL_TEXTURE_COMPRESSED_IMAGE_SIZE are accepted.

       params
           Returns the requested data.

DESCRIPTION
       glGetTexLevelParameter returns in params texture parameter values for a specific level-of-detail
       value, specified as level.  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.


       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 and borders, but a long skinny
       texture, or a texture without mipmaps and borders, 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, 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. This value includes the border of
           the texture image. The initial value is 0.

       GL_TEXTURE_HEIGHT


           params returns a single value, the height of the texture image. This value includes the border of
           the texture image. The initial value is 0.

       GL_TEXTURE_DEPTH


           params returns a single value, the depth of the texture image. This value includes the border 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().

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.

ERRORS
       GL_INVALID_ENUM is generated 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.

SEE ALSO
       glActiveTexture(), glGetTexParameter(), glCopyTexImage1D(), glCopyTexImage2D(),
       glCopyTexSubImage1D(), glCopyTexSubImage2D(), glCopyTexSubImage3D(), glTexImage1D(), glTexImage2D(),
       glTexImage3D(), glTexSubImage1D(), glTexSubImage2D(), glTexSubImage3D(), glTexParameter()


COPYRIGHT
       Copyright (C) 1991-2006 Silicon Graphics, Inc. Copyright (C) 2010 Khronos Group. This document is
       licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.



OpenGL 3.3                                       03/08/2011                         GLGETTEXLEVELPARAMET(3G)