- return texture environment parameters
C SPECIFICATION
PARAMETERS
_param1 Specifies a texture environment. Must be
GL_TEXTURE_ENV.
_param2 Specifies the symbolic name of a texture environ-
ment parameter. Accepted values are
GL_TEXTURE_ENV_MODE and GL_TEXTURE_ENV_COLOR.
_param3 Returns the requested data.
DESCRIPTION
glGetTexEnv returns in _param3 selected values of a tex-
ture environment that was specified with glTexEnv.
_param1 specifies a texture environment. Currently, only
one texture environment is defined and supported:
GL_TEXTURE_ENV.
_param2 names a specific texture environment parameter, as
follows:
GL_TEXTURE_ENV_MODE
_param3 returns the single-valued texture envi-
ronment mode, a symbolic constant. The initial
value is GL_MODULATE.
GL_TEXTURE_ENV_COLOR
_param3 returns four integer or floating-point
values that are the texture environment color.
Integer values, when requested, are linearly
mapped from the internal floating-point repre-
sentation such that 1.0 maps to the most posi-
tive representable integer, and -1.0 maps to the
most negative representable integer. The initial
value is (0, 0, 0, 0).
NOTES
If an error is generated, no change is made to the con-
tents of _param3.
When the GL_ARB_multitexture extension is supported,
glGetTexEnv returns the texture environment parameters for
the active texture unit.
ERRORS
GL_INVALID_ENUM is generated if _param1 or _param2 is not
an accepted value.
GL_INVALID_OPERATION is generated if glGetTexEnv is exe-