SGIS_generate_mipmap
GL_SGIS_generate_mipmap
SGI Date: 1997/02/26 03:36:30 SGI Revision: 1.6
$Id: //sw/main/docs/OpenGL/specs/GL_SGIS_generate_mipmap.txt#2 $
32
EXT_texture is required
EXT_texture3D affects the definition of this extension
EXT_texture_object affects the definition of this extension
SGIS_texture_lod affects the definition of this extension
This extension defines a mechanism by which OpenGL can derive the
entire set of mipmap arrays when provided with only the base level
array. Automatic mipmap generation is particularly useful when
texture images are being provided as a video stream.
* How are edges handled?
   New Procedures and Functions |
None
Accepted by the <pname> parameter of TexParameteri, TexParameterf,
TexParameteriv, TexParameterfv, GetTexParameteriv, and GetTexParameterfv:
GENERATE_MIPMAP_SGIS 0x8191
Accepted by the <target> parameter of Hint, and by the <pname>
parameter of GetBooleanv, GetIntegerv, GetFloatv, and GetDoublev:
GENERATE_MIPMAP_HINT_SGIS 0x8192
| Additions to Chapter 2 of the 1.0 Specification (OpenGL Operation) |
None
| Additions to Chapter 3 of the 1.0 Specification (Rasterization) |
GL Specification Table 3.7 is updated as follows:
Name Type Legal Values
---- ---- ------------
TEXTURE_WRAP_S integer CLAMP, REPEAT
TEXTURE_WRAP_T integer CLAMP, REPEAT
TEXTURE_WRAP_R_EXT integer CLAMP, REPEAT
TEXTURE_MIN_FILTER integer NEAREST, LINEAR,
NEAREST_MIPMAP_NEAREST,
NEAREST_MIPMAP_LINEAR,
LINEAR_MIPMAP_NEAREST,
LINEAR_MIPMAP_LINEAR,
FILTER4_SGIS
TEXTURE_MAG_FILTER integer NEAREST, LINEAR,
FILTER4_SGIS,
LINEAR_DETAIL_SGIS,
LINEAR_DETAIL_ALPHA_SGIS,
LINEAR_DETAIL_COLOR_SGIS,
LINEAR_SHARPEN_SGIS,
LINEAR_SHARPEN_ALPHA_SGIS,
LINEAR_SHARPEN_COLOR_SGIS
TEXTURE_BORDER_COLOR 4 floats any 4 values in [0,1]
DETAIL_TEXTURE_LEVEL_SGIS integer any non-negative integer
DETAIL_TEXTURE_MODE_SGIS integer ADD, MODULATE
TEXTURE_MIN_LOD_SGIS float any value
TEXTURE_MAX_LOD_SGIS float any value
TEXTURE_BASE_LEVEL_SGIS integer any non-negative integer
TEXTURE_MAX_LEVEL_SGIS integer any non-negative integer
GENERATE_MIPMAP_SGIS boolean TRUE or FALSE
Table 3.7: Texture parameters and their values.
This extension introduces a side effect to the modification of the
base level mipmap array. The side effect is enabled on a per-texture
basis by calling TexParameteri, TexParameterf, TexParameteriv, or
TexParameterfv with <target> set to TEXTURE_1D, TEXTURE_2D, or
TEXTURE_3D_EXT, <pname> set to GENERATE_MIPMAP_SGIS, and <param>
set to TRUE (or <params> pointing to TRUE). It is disabled using the
same call, with <param> set to FALSE, or <params> pointing to FALSE.
If SGIS_texture_lod is supported, the base level array is the array
number TEXTURE_BASE_LEVEL_SGIS. Otherwise the base level array is
array zero.
If GENERATE_MIPMAP_SGIS is enabled, the side effect occurs whenever
any change is made to the interior or edge image values of the base
level texture array. The side effect is computation of a complete
set of mipmap arrays, all derived from the modified base level array.
Array levels BASE+1 through BASE+p are replaced with derived arrays,
regardless of their previous contents. All other texture arrays,
including the base array, are left unchanged by this mipmap computation.
The internal formats and border widths of the derived mipmap arrays
all match those of the base array, and the dimensions of the derived
arrays follow the requirements described in the Mipmapping section of
the GL Specification. The result is that the set of mipmap arrays is
complete as defined by the GL Specification. The contents of the
derived image arrays are computed by repeated, filtered reduction of
the base level image array. This specification does not require any
particular filter algorithm, though a simple 2x2 box filter is
recommended as the default filter. Hint variable
GENERATE_MIPMAP_HINT_SGIS can be changed from its default value of
DONT_CARE to either FASTEST or NICEST, indicating to the implementation
that either the fastest or highest quality filter operation is desired.
These operations are not defined by this specification, however. The
single hint value controls the filtering of all the textures, and is
evaluated when the filtering operation takes place.
Automatic mipmap generation is available for texture targets TEXTURE_1D,
TEXTURE_2D, and TEXTURE_3D_EXT only.
| Additions to Chapter 4 of the 1.0 Specification (Per-Fragment Operations and the Frame Buffer) |
None
| Additions to Chapter 5 of the 1.0 Specification (Special Functions) |
None
| Additions to Chapter 6 of the 1.0 Specification (State and State Requests) |
None
| Additions to the GLX Specification |
None
| Dependencies on EXT_texture |
EXT_texture is required.
| Dependencies on EXT_texture3D |
If EXT_texture3D is not supported, references to 3D texture mapping and
to TEXTURE_3D_EXT in this document are invalid and should be ignored.
| Dependencies on EXT_texture_object |
If EXT_texture_object is implemented, the state value named
GENERATE_MIPMAP_SGIS
is added to the state vector of each texture object. When an attribute
set that includes texture information is popped, the bindings and
enables are first restored to their pushed values, then the bound
textures have their GENERATE_MIPMAP_SGIS parameters restored to their
pushed values.
| Dependencies on SGIS_texture_lod |
If SGIS_texture_lod is not supported, the base array level is always
level zero. References in this document to TEXTURE_BASE_LEVEL_SGIS
should be ignored.
None
Initial
Get Value Get Command Type Value Attrib
--------- ----------- ---- ------- ------
GENERATE_MIPMAP_SGIS GetTexParameteriv B FALSE texture
GENERATE_MIPMAP_HINT_SGIS GetIntegerv Z3 DONT_CARE hint
| New Implementation Dependent State |
None
None
 |  | Last update: November 14, 2006.
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