Specifies a texture environment. Must be GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV.
_p_n_a_m_e
Specifies the symbolic name of a texture environment parameter.
Accepted values are GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV____MMMMOOOODDDDEEEE, GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV____CCCCOOOOLLLLOOOORRRR, and
Specifies a pointer to a parameter array that contains either a
single symbolic constant or an RGBA color.
DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
A texture environment specifies how texture values are interpreted when a
fragment is textured. _t_a_r_g_e_t must be GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV. _p_n_a_m_e can be
GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV____MMMMOOOODDDDEEEE, GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV____CCCCOOOOLLLLOOOORRRR, or GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV____BBBBIIIIAAAASSSS____SSSSGGGGIIIIXXXX.
A texture function acts on the fragment to be textured using the texture
image value that applies to the fragment (see ggggllllTTTTeeeexxxxPPPPaaaarrrraaaammmmeeeetttteeeerrrr) and
produces an RGBA color for that fragment. The following tables show how
the RGBA color is produced for each of the texture functions. C is a
triple of color values (RGB) and A is the associated alpha value. RGBA
values extracted from a texture image are in the range [0,1]. The
subscript f refers to the incoming fragment, the subscript t to the
texture image, the subscript c to the texture environment color, the
subscript b to the texture environment bias color, and subscript v
indicates a value produced by the texture function.
A texture image can have up to four components per texture element (see
ggggllllTTTTeeeexxxxIIIImmmmaaaaggggeeee1111DDDD and ggggllllTTTTeeeexxxxIIIImmmmaaaaggggeeee2222DDDD). In an image of GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE format L
t
indicates the single component. In an image of GGGGLLLL____AAAALLLLPPPPHHHHAAAA format A
t
indicates the single component. In an image of GGGGLLLL____IIIINNNNTTTTEEEENNNNSSSSIIIITTTTYYYY format I
t
indicates the single component. A two-component image uses L and A . A
t t
three-component image has only a color value, C . A four-component image
If _p_n_a_m_e is GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV____CCCCOOOOLLLLOOOORRRR, _p_a_r_a_m_s is a pointer to an array that
holds an RGBA color consisting of four values. Integer color components
are interpreted linearly such that the most positive integer maps to 1.0,
and the most negative integer maps to -1.0. The values are clamped to
the range [0,1] when they are specified. C takes these four values.
c
If _p_n_a_m_e is GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV____BBBBIIIIAAAASSSS____SSSSGGGGIIIIXXXX, _p_a_r_a_m_s is a pointer to an array
that holds an RGBA color consisting of four values. Integer color
components are interpreted linearly such that the most positive integer
maps to 1.0, and the most negative integer maps to -1.0. The values are
clamped to the range [0,1] when they are specified. C takes these four
b
values.
GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV____MMMMOOOODDDDEEEE defaults to GGGGLLLL____MMMMOOOODDDDUUUULLLLAAAATTTTEEEE, GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV____CCCCOOOOLLLLOOOORRRR
defaults to (0,0,0,0), and GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV____BBBBIIIIAAAASSSS____SSSSGGGGIIIIXXXX defaults to
(0,0,0,0).
NNNNOOOOTTTTEEEESSSS
GGGGLLLL____RRRREEEEPPPPLLLLAAAACCCCEEEE may only be used if the GL version is 1.1 or greater.
GGGGLLLL____RRRREEEEPPPPLLLLAAAACCCCEEEE____EEEEXXXXTTTT is part of the EEEEXXXXTTTT____tttteeeexxxxttttuuuurrrreeee extension. GGGGLLLL____AAAADDDDDDDD and is part
of both the SSSSGGGGIIIIXXXX____tttteeeexxxxttttuuuurrrreeee____aaaadddddddd____eeeennnnvvvv and EEEEXXXXTTTT____tttteeeexxxxttttuuuurrrreeee____eeeennnnvvvv____eeeennnnvvvv extensions
although the texture function it enables differs between the two
extensions. GGGGLLLL____TTTTEEEEXXXXTTTTUUUURRRREEEE____EEEENNNNVVVV____BBBBIIIIAAAASSSS____SSSSGGGGIIIIXXXX is part of the SSSSGGGGIIIIXXXX____tttteeeexxxxttttuuuurrrreeee____aaaadddddddd____eeeennnnvvvv
extension. See ggggllllIIIInnnnttttrrrroooo for more information concerning extensions.
EEEERRRRRRRROOOORRRRSSSS
GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____EEEENNNNUUUUMMMM is generated when _t_a_r_g_e_t or _p_n_a_m_e is not one of the
accepted defined values, or when _p_a_r_a_m_s should have a defined constant
value (based on the value of _p_n_a_m_e) and does not.
GGGGLLLL____IIIINNNNVVVVAAAALLLLIIIIDDDD____OOOOPPPPEEEERRRRAAAATTTTIIIIOOOONNNN is generated if ggggllllTTTTeeeexxxxEEEEnnnnvvvv is executed between the
execution of ggggllllBBBBeeeeggggiiiinnnn and the corresponding execution of ggggllllEEEEnnnndddd.
RRRReeeeaaaalllliiiittttyyyyEEEEnnnnggggiiiinnnneeee, RRRReeeeaaaalllliiiittttyyyyEEEEnnnnggggiiiinnnneeee2222, and VVVVTTTTXXXX and HHHHiiiigggghhhh IIIImmmmppppaaaacccctttt and MMMMaaaaxxxxiiiimmmmuuuummmm IIIImmmmppppaaaacccctttt
systems do not support GGGGLLLL____RRRREEEEPPPPLLLLAAAACCCCEEEE____EEEEXXXXTTTT.
With HHHHiiiigggghhhh IIIImmmmppppaaaacccctttt and MMMMaaaaxxxxiiiimmmmuuuummmm IIIImmmmppppaaaacccctttt on Indigo2 systems, the GGGGLLLL____BBBBLLLLEEEENNNNDDDD mode
is supported for GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE and GGGGLLLL____LLLLUUUUMMMMIIIINNNNAAAANNNNCCCCEEEE____AAAALLLLPPPPHHHHAAAA textures only. HHHHiiiigggghhhh
IIIImmmmppppaaaacccctttt and MMMMaaaaxxxxiiiimmmmuuuummmm IIIImmmmppppaaaacccctttt on Octane systems supports all but GGGGLLLL____RRRRGGGGBBBBAAAA.
Specifying this mode for the unsupported texture formats will result in
texture-mapping being effectively disabled.
The SSSSGGGGIIIIXXXX____tttteeeexxxxttttuuuurrrreeee____aaaadddddddd____eeeennnnvvvv extension is supported only on IIIInnnnffffiiiinnnniiiitttteeeeRRRReeeeaaaalllliiiittttyyyy
systems. There is a significant restriction on the texture environment
bias color, however. Only two values are allowed for the bias: zero, or
exactly -0.5 times the texture environment color. (This makes the
expression C C +C equivalent to C C or (C -0.5)C , respectively.)
Please note that this extension is not the same as the
EEEEXXXXTTTT____tttteeeexxxxttttuuuurrrreeee____eeeennnnvvvv____aaaadddddddd extension despite the potentially confusing
similarity between names.
The EEEEXXXXTTTT____tttteeeexxxxttttuuuurrrreeee____eeeennnnvvvv____aaaadddddddd extension is supported only on OOOOccccttttaaaannnneeee2222 VVVVPPPPrrrroooo
systems. Please note that it is not the same as the SSSSGGGGIIIIXXXX____tttteeeexxxxttttuuuurrrreeee____aaaadddddddd____eeeennnnvvvv
extension despite the potentially confusing similarity between names.