MirOS Manual: glGetTexLevelParameter(3), glGetTexLevelParameterfv(3), glGetTexLevelParameteriv(3)


GLGETTEXLEVELPARAMETEUNIX)Programmer's GLGETTEXLEVELPARAMETER(3G)

NAME

     glGetTexLevelParameterfv, glGetTexLevelParameteriv - 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,
             either GL_TEXTURE_1D, GL_TEXTURE_2D, GL_TEXTURE_3D,
             GL_PROXY_TEXTURE_1D, GL_PROXY_TEXTURE_2D, or
             GL_PROXY_TEXTURE_3D.

     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_LUMINANCE_SIZE,
             and GL_TEXTURE_INTENSITY_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, or
     GL_PROXY_TEXTURE_3D.

     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 confi-
     guration. If the texture cannot be accommodated, the texture

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GLGETTEXLEVELPARAMETEUNIX)Programmer's GLGETTEXLEVELPARAMETER(3G)

     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  of
               the texture image.

     GL_TEXTURE_BORDER
               params returns a single value, the width in pixels
               of the border of the texture image. The initial
               value is 0.

     GL_TEXTURE_RED_SIZE,

     GL_TEXTURE_GREEN_SIZE,

     GL_TEXTURE_BLUE_SIZE,

     GL_TEXTURE_ALPHA_SIZE,

     GL_TEXTURE_LUMINANCE_SIZE,

     GL_TEXTURE_INTENSITY_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.

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GLGETTEXLEVELPARAMETEUNIX)Programmer's GLGETTEXLEVELPARAMETER(3G)

NOTES

     If an error is generated, no change is made to the contents
     of params.

     GL_TEXTURE_INTERNAL_FORMAT is available only if the GL ver-
     sion is 1.1 or greater. In version 1.0, use
     GL_TEXTURE_COMPONENTS instead.

     GL_PROXY_TEXTURE_1D and GL_PROXY_TEXTURE_2D are available
     only if the GL version is 1.1 or greater.

     GL_TEXTURE_3D, GL_PROXY_TEXTURE_3D, and GL_TEXTURE_DEPTH are
     available only if the GL version is 1.2 or greater.

     When the GL_ARB_multitexture extension is supported,
     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
     log2 max, where max is the returned value of
     GL_MAX_TEXTURE_SIZE.

     GL_INVALID_OPERATION is generated if glGetTexLevelParameter
     is executed between the execution of glBegin and the
     corresponding execution of glEnd.

SEE ALSO

     glActiveTextureARB(3G), glGetTexParameter(3G),
     glCopyTexImage1D(3G), glCopyTexImage2D(3G),
     glCopyTexSubImage1D(3G), glCopyTexSubImage2D(3G),
     glCopyTexSubImage3D(3G), glTexEnv(3G), glTexGen(3G),
     glTexImage1D(3G), glTexImage2D(3G), glTexImage3D(3G),
     glTexSubImage1D(3G), glTexSubImage2D(3G),
     glTexSubImage3D(3G), glTexParameter(3G)

MirOS BSD #10-current  Printed 03.04.2017                       3

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