glGetTexParameter(3G) OpenGL Reference glGetTexParameter(3G)
glGetTexParameterfv, glGetTexParameteriv - return texture parameter
values
void glGetTexParameterfv( GLenum target,
GLenum pname,
GLfloat *params )
void glGetTexParameteriv( GLenum target,
GLenum pname,
GLint *params )
target Specifies the symbolic name of the target texture.
GL_TEXTURE_1D, GL_TEXTURE_2D, GL_DETAIL_TEXTURE_2D_SGIS, and
GL_TEXTURE_3D_EXT are accepted.
pname Specifies the symbolic name of a texture parameter.
GL_TEXTURE_MAG_FILTER, GL_TEXTURE_MIN_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, GL_DETAIL_TEXTURE_LEVEL_SGIS,
GL_DETAIL_TEXTURE_MODE_SGIS, GL_DETAIL_TEXTURE_FUNC_POINTS_SGIS,
GL_SHARPEN_TEXTURE_FUNC_POINTS_SGIS,
GL_POST_TEXTURE_FILTER_BIAS_SGIX,
GL_POST_TEXTURE_FILTER_SCALE_SGIX, GL_TEXTURE_PRIORITY,
GL_TEXTURE_PRIORITY_EXT, GL_TEXTURE_RESIDENT,
GL_TEXTURE_RESIDENT_EXT, GL_TEXTURE_MIN_LOD_SGIS,
GL_TEXTURE_MAX_LOD_SGIS, GL_TEXTURE_BASE_LEVEL_SGIS,
GL_TEXTURE_MAX_LEVEL_SGIS, GL_TEXTURE_LOD_BIAS_S_SGIX,
GL_TEXTURE_LOD_BIAS_T_SGIX, GL_TEXTURE_LOD_BIAS_R_SGIX,
GL_TEXTURE_MAX_CLAMP_S_SGIX, GL_TEXTURE_MAX_CLAMP_T_SGIX,
GL_TEXTURE_MAX_CLAMP_R_SGIX, GL_DUAL_TEXTURE_SELECT_SGIS,
GL_QUAD_TEXTURE_SELECT_SGIS, GL_TEXTURE_FILTER4_SIZE_SGIS,
GL_TEXTURE_CLIPMAP_FRAME_SGIX, GL_TEXTURE_CLIPMAP_CENTER_SGIX,
GL_TEXTURE_CLIPMAP_OFFSET_SGIX,
GL_TEXTURE_CLIPMAP_VIRTUAL_DEPTH_SGIX, GL_TEXTURE_COMPARE_SGIX,
GL_TEXTURE_COMPARE_OPERATOR_SGIX, and GL_SHADOW_AMBIENT_SGIX are
accepted.
params Returns the texture parameters.
glGetTexParameter returns in params the value or values of the texture
parameter specified as pname. target defines the target texture, either
GL_TEXTURE_1D, GL_TEXTURE_2D, or GL_TEXTURE_3D to specify one-, two-, or
three-dimensional texturing. pname accepts the same symbols as
glTexParameter, with the same interpretations:
Page 1
glGetTexParameter(3G) OpenGL Reference glGetTexParameter(3G)
GL_TEXTURE_MAG_FILTER Returns the single-valued texture
magnification filter, a symbolic
constant. The initial value is
GL_LINEAR.
GL_TEXTURE_MIN_FILTER Returns the single-valued texture
minification filter, a symbolic
constant. The initial value is
GL_NEAREST_MIPMAP_LINEAR.
GL_TEXTURE_MIN_LOD Returns the single-valued texture
minimum level-of-detail value. The
initial value is -1000.
GL_TEXTURE_MAX_LOD Returns the single-valued texture
maximum level-of-detail value. The
initial value is 1000.
GL_TEXTURE_BASE_LEVEL Returns the single-valued base texture
mipmap level. The initial value is 0.
GL_TEXTURE_MAX_LEVEL Returns the single-valued maximum
texture mipmap array level. The
initial value is 1000.
GL_TEXTURE_WRAP_S Returns the single-valued wrapping
function for texture coordinate s, a
symbolic constant. The initial value
is GL_REPEAT.
GL_TEXTURE_WRAP_T Returns the single-valued wrapping
function for texture coordinate t, a
symbolic constant. The initial value
is GL_REPEAT.
GL_TEXTURE_WRAP_R Returns the single-valued wrapping
function for texture coordinate r, a
symbolic constant. The initial value
is GL_REPEAT.
GL_TEXTURE_BORDER_COLOR Returns four integer or floating-point
numbers that comprise the RGBA color
of the texture border. Floating-point
values are returned in the range [0,
1]. Integer values are returned as a
linear mapping of the internal
floating-point representation such
that 1.0 maps to the most positive
representable integer and -1.0 maps to
the most negative representable
integer. The initial value is (0, 0,
0, 0).
Page 2
glGetTexParameter(3G) OpenGL Reference glGetTexParameter(3G)
GL_DETAIL_TEXTURE_LEVEL_SGIS Returns an integer specifying the
number of levels that separate the
level zero image of GL_TEXTURE_2D and
the image of
GL_DETAIL_TEXTURE_2D_SGIS. See
glDetailTexFuncSGIS for more
information.
GL_DETAIL_TEXTURE_MODE_SGIS Returns a single enumerated value
describing the detail texture mode.
See glDetailTexFuncSGIS.
GL_DETAIL_TEXTURE_FUNC_POINTS_SGIS Returns the number of points in the
specification of the detail texture
scaling function. See
glGetDetailTexFuncSGIS.
GL_SHARPEN_TEXTURE_FUNC_POINTS_SGIS [Toc] [Back]
Returns the number of points in the
specification of the sharpen texture
scaling function. See
glGetSharpenTexFuncSGIS.
GL_TEXTURE_LOD_BIAS_S_SGIX Returns the single-valued bias amount
added to the intermediate texture LOD
calculated for the s dimension of
target. See glTexParameter for more
information.
GL_TEXTURE_LOD_BIAS_T_SGIX Returns the single-valued bias amount
added to the intermediate texture LOD
calculated for the t dimension of
target. See glTexParameter for more
information.
GL_TEXTURE_LOD_BIAS_R_SGIX Returns the single-valued bias amount
added to the intermediate texture LOD
calculated for the r dimension of
target. See glTexParameter for more
information.
GL_TEXTURE_MAX_CLAMP_S_SGIX Returns the single-valued maximum to
which the s coordinate of target is
clamped when GL_TEXTURE_WRAP_S is set
to GL_CLAMP, GL_CLAMP_TO_EDGE, or
GL_CLAMP_TO_BORDER_SGIS. The initial
value is 1.
GL_TEXTURE_MAX_CLAMP_T_SGIX Returns the single-valued maximum to
which the t coordinate of target is
clamped when GL_TEXTURE_WRAP_T is set
to GL_CLAMP, GL_CLAMP_TO_EDGE, or
Page 3
glGetTexParameter(3G) OpenGL Reference glGetTexParameter(3G)
GL_CLAMP_TO_BORDER_SGIS. The initial
value is 1.
GL_TEXTURE_MAX_CLAMP_R_SGIX Returns the single-valued maximum to
which the r coordinate of target is
clamped when GL_TEXTURE_WRAP_R is set
to GL_CLAMP, GL_CLAMP_TO_EDGE, or
GL_CLAMP_TO_BORDER_SGIS. The initial
value is 1.
GL_POST_TEXTURE_FILTER_BIAS_SGIX Returns four floating-point numbers
that comprise the R, G, B and A bias
factors for the texture. See
glTexParameterfv and glTexParameteriv.
GL_POST_TEXTURE_FILTER_SCALE_SGIX Returns four floating-point numbers
that comprise the R, G, B and A scale
factors for the texture. See
glTexParameterfv and glTexParameteriv.
GL_TEXTURE_PRIORITY Returns the residence priority of the
target texture (or the named texture
bound to it). The initial value is 1.
See glPrioritizeTextures.
GL_TEXTURE_PRIORITY_EXT Returns the residence priority of the
target texture (or the named texture
bound to it). See
glPrioritizeTexturesEXT.
GL_TEXTURE_RESIDENT Returns the residence status of the
target texture. If the value returned
in params is GL_TRUE, the texture is
resident in texture memory. See
glAreTexturesResident.
GL_TEXTURE_RESIDENT_EXT Returns the residence status of the
target texture. If the value returned
in params is GL_TRUE, the texture is
resident in texture memory. See
glAreTexturesResidentEXT.
GL_TEXTURE_MIN_LOD_SGIS Returns the low end of the LOD
clamping range.
GL_TEXTURE_MAX_LOD_SGIS Returns the high end of the LOD
clamping range.
GL_TEXTURE_BASE_LEVEL_SGIS Returns the base level of the mipmap
set associated with target.
Page 4
glGetTexParameter(3G) OpenGL Reference glGetTexParameter(3G)
GL_TEXTURE_MAX_LEVEL_SGIS Returns the maximum level of the
mipmap set associated with target.
GL_DUAL_TEXTURE_SELECT_SGIS Returns the currently selected
component group for GL_DUAL_ textures.
Its value is 0 or 1. See
glTexParameter, glTexImage1D,
glTexImage2D and glTexImage3DEXT.
GL_QUAD_TEXTURE_SELECT_SGIS, Returns the currently selected
component group for GL_QUAD_ textures.
Its value is 0, 1, 2 or 3. See
glTexParameter, glTexImage1D,
glTexImage2D and glTexImage3DEXT.
GL_TEXTURE_FILTER4_SIZE_SGIS Returns the implementation-dependent
texture filtering constant Size used
by the SGIS_texture_filter4 extension.
For an explanation of this constant,
see glTexFilterFuncSGIS.
GL_TEXTURE_CLIPMAP_FRAME_SGIX Returns the size of the texture memory
area reserved for paging new texels
into a clipmap. The size is expressed
as a (floating-point) fraction of half
the width of a clipped level. See
glTexParameter for more information.
GL_TEXTURE_CLIPMAP_CENTER_SGIX Returns the s and t coordinates of the
center of a clipmap's region of
interest. See glTexParameter for more
information.
GL_TEXTURE_CLIPMAP_OFFSET_SGIX Returns the s and t toroidal offsets
for a clipmap. See glTexParameter for
more information.
GL_TEXTURE_CLIPMAP_VIRTUAL_DEPTH_SGIX [Toc] [Back]
Returns the lod offset, depth, and
virtual depth, respectively, for a
clipmap. See glTexParameter for more
information.
GL_TEXTURE_COMPARE_SGIX Returns a single Boolean value
indicating whether the texture
comparison operation is enabled. See
glTexParameter for more information.
GL_TEXTURE_COMPARE_OPERATOR_SGIX Returns the current texture comparison
operator. See glTexParameter for more
information.
Page 5
glGetTexParameter(3G) OpenGL Reference glGetTexParameter(3G)
GL_SHADOW_AMBIENT_SGIX Returns the current ambient lighting
coefficient for shadows. See
glTexParameter for more information.
GL_TEXTURE_PRIORITY and GL_TEXTURE_RESIDENT are available only if the GL
version is 1.1 or greater.
GL_TEXTURE_3D, GL_TEXTURE_MIN_LOD, GL_TEXTURE_MAX_LOD,
GL_TEXTURE_BASE_LEVEL, GL_TEXTURE_MAX_LEVEL, and GL_TEXTURE_WRAP_R are
available only if the GL version is 1.2 or greater.
If an error is generated, no change is made to the contents of params.
GL_TEXTURE_WRAP_R_EXT is part of the EXT_texture3D extension.
GL_DETAIL_TEXTURE_LEVEL_SGIS, GL_DETAIL_TEXTURE_MODE_SGIS, and
GL_DETAIL_TEXTURE_FUNC_POINTS_SGIS are part of the SGIS_detail_texture
extension. GL_SHARPEN_TEXTURE_FUNC_POINTS_SGIS is part of the
SGIS_sharpen_texture extension. GL_POST_TEXTURE_FILTER_BIAS_SGIX and
GL_POST_TEXTURE_FILTER_SCALE_SGIX are part of the SGIX_texture_scale_bias
extension. GL_TEXTURE_PRIORITY_EXT and GL_TEXTURE_RESIDENT_EXT are part
of the EXT_texture_object extension. GL_TEXTURE_MIN_LOD_SGIS
GL_TEXTURE_MAX_LOD_SGIS, GL_TEXTURE_BASE_LEVEL_SGIS, and
GL_TEXTURE_MAX_LEVEL_SGIS are part of the SGIS_texture_lod extension.
GL_DUAL_TEXTURE_SELECT_SGIS and GL_QUAD_TEXTURE_SELECT_SGIS are part of
the SGIS_texture_select extension. GL_TEXTURE_FILTER4_SIZE_SGIS is part
of the SGIS_texture_filter4 extension. GL_TEXTURE_CLIPMAP_FRAME_SGIX,
GL_TEXTURE_CLIPMAP_CENTER_SGIX, GL_TEXTURE_CLIPMAP_OFFSET_SGIX, and
GL_TEXTURE_CLIPMAP_VIRTUAL_DEPTH_SGIX are part of the SGIX_clipmap
extension. GL_TEXTURE_COMPARE_SGIX and GL_TEXTURE_COMPARE_OPERATOR_SGIX
are part of the SGIX_shadow extension. GL_SHADOW_AMBIENT_SGIX is part of
the SGIX_shadow_ambient extension.
GL_TEXTURE_LOD_BIAS_S_SGIX,GL_TEXTURE_LOD_BIAS_T_SGIX, and
GL_TEXTURE_LOD_BIAS_R_SGIX are part of the SGIX_texture_lod_bias
extension. GL_TEXTURE_MAX_CLAMP_S_SGIX, GL_TEXTURE_MAX_CLAMP_T_SGIX, and
GL_TEXTURE_MAX_CLAMP_R_SGIX are part of the SGIX_texture_coordinate_clamp
extension. See glIntro for more information on using extensions.
GL_INVALID_ENUM is generated if target or pname is not an accepted value.
GL_INVALID_ENUM is generated if pname is GL_TEXTURE_FILTER4_SIZE_SGIS and
target is not GL_TEXTURE_1D or GL_TEXTURE_2D.
GL_INVALID_OPERATION is generated if glGetTexParameter is executed
between the execution of glBegin and the corresponding execution of
glEnd.
Page 6
glGetTexParameter(3G) OpenGL Reference glGetTexParameter(3G)
MACHINE DEPENDENCIES
The SGIX_clipmap extension is supported only on InfiniteReality systems.
The following restrictions apply:
1. For best performance, the ``breakpoint'' clipmap level (B) must
be loaded before any other level. The implementation derives
the size of the clipmap from the size of this level, so loading
this level first permits efficient allocation of texture memory.
2. Clipmaps must be square.
3. GL_TEXTURE_WRAP_S and GL_TEXTURE_WRAP_T must be set to
GL_CLAMP_TO_EDGE_SGIS.
4. It is more efficient to set clipmap attributes that affect
texture memory allocation (such as
GL_TEXTURE_CLIPMAP_FRAME_SGIX) before loading the first level of
the clipmap, rather than after loading it.
5. Virtual clipmaps (whose GL_TEXTURE_CLIPMAP_VIRTUAL_DEPTH_SGIX
parameters have been defined) use texture memory inefficiently.
Each level of detail allocates a region of texture memory the
same size as that of a clipped level. Any clipmap whose depth
is less than GL_MAX_CLIPMAP_DEPTH_SGIX should avoid this by not
specifying GL_TEXTURE_CLIPMAP_VIRTUAL_DEPTH_SGIX parameters. An
application can not readback the texture levels whose size is
smaller than that of the clipped level.
6. The depth of the virtual clipmap given in
GL_TEXTURE_CLIPMAP_VIRTUAL_DEPTH_SGIX must be defined before any
texture levels are downloaded, and it can not be changed once it
has been specified. If the application tries to change the
virtual depth, no action is taken.
7. When using virtual clipmaps, an application should not
overcommit texture memory. Doing so will result in undefined
behavior.
RealityEngine, RealityEngine2, and VTX systems do not support
GL_DETAIL_TEXTURE_LEVEL_SGIS correctly.
The SGIX_texture_lod_bias extension is supported only on Octane2 VPro
systems and InfiniteReality systems.
On InfiniteReality systems, if the post-texture filter scale and bias
values are set to values other than the defaults, they are limited to the
range [0.0, 1.0). (note: this range excludes 1.0.) The
SGIX_texture_scale_bias extension is not supported on RealityEngine,
RealityEngine2, and VTX systems or on High Impact and Maximum Impact
systems.
Page 7
glGetTexParameter(3G) OpenGL Reference glGetTexParameter(3G)
The SGIS_texture_select extension is supported only on InfiniteReality
systems, High Impact and Maximum Impact on Octane systems, and High
Impact and Maximum Impact on Indigo2 systems with the TRAM option card.
The SGIS_texture_filter4 extension is supported only on InfiniteReality
systems.
On InfiniteReality systems, GL_INVALID_VALUE is generated if the value of
the argument n to the command glTexFilterFuncSGIS does not equal the
value of the implementation dependent constant Size, which can be
determined by calling glGetTexParameter with argument
GL_TEXTURE_FILTER4_SIZE_SGIS. This restriction will be removed in a
future release.
GL_TEXTURE_MAX_CLAMP_S_SGIX, GL_TEXTURE_MAX_CLAMP_T_SGIX, and
GL_TEXTURE_MAX_CLAMP_S_SGIX are only supported on Octane2 VPro systems.
glAreTexturesResident, glPrioritizeTextures, glTexParameter
PPPPaaaaggggeeee 8888 [ Back ]
|
