gl.TexEnv(pname, param)
pname
can be either #GL_TEXTURE_ENV_MODE
or #GL_TEXTURE_ENV_COLOR
. If pname
is #GL_TEXTURE_ENV_MODE
, then param
must be the symbolic name of a texture function. Four texture
functions may be specified: #GL_MODULATE
, #GL_DECAL
, #GL_BLEND
, and #GL_REPLACE
.
A texture function acts on the fragment to be textured using the texture image value that applies to the fragment (See gl.TexParameter for details.) and produces an RGBA color for that fragment. See an OpenGL reference manual for information on how the RGBA color is produced for each of the three texture functions that can be chosen.
If pname
is #GL_TEXTURE_ENV_COLOR
, param
must be a table containing an array that holds an RGBA color consisting of four floating-point values.
#GL_TEXTURE_ENV_MODE
defaults to #GL_MODULATE
and #GL_TEXTURE_ENV_COLOR
defaults to (0, 0, 0, 0)
Please consult an OpenGL reference manual for more information.
#GL_INVALID_ENUM
is generated when pname
is not one of the accepted defined values, or when param
should have a defined constant value (based on the value of pname
) and does not.
#GL_INVALID_OPERATION
is generated if gl.TexEnv()
is executed between the execution of gl.Begin() and the corresponding execution of gl.End().