GLGETTEXENV(3G) OpenGL Manual GLGETTEXENV(3G)
NAME
glGetTexEnv - return texture environment parameters
C SPECIFICATION
void glGetTexEnvfv(GLenum target, GLenum pname, GLfloat * params);
void glGetTexEnviv(GLenum target, GLenum pname, GLint * params);
PARAMETERS
target
Specifies a texture environment. May be GL_TEXTURE_ENV, GL_TEXTURE_FILTER_CONTROL, or GL_POINT_SPRITE.
pname
Specifies the symbolic name of a texture environment parameter. Accepted values are GL_TEXTURE_ENV_MODE, GL_TEXTURE_ENV_COLOR,
GL_TEXTURE_LOD_BIAS, GL_COMBINE_RGB, GL_COMBINE_ALPHA, GL_SRC0_RGB, GL_SRC1_RGB, GL_SRC2_RGB, GL_SRC0_ALPHA, GL_SRC1_ALPHA,
GL_SRC2_ALPHA, GL_OPERAND0_RGB, GL_OPERAND1_RGB, GL_OPERAND2_RGB, GL_OPERAND0_ALPHA, GL_OPERAND1_ALPHA, GL_OPERAND2_ALPHA,
GL_RGB_SCALE, GL_ALPHA_SCALE, or GL_COORD_REPLACE.
params
Returns the requested data.
DESCRIPTION
glGetTexEnv returns in params selected values of a texture environment that was specified with glTexEnv(). target specifies a texture
environment.
When target is GL_TEXTURE_FILTER_CONTROL, pname must be GL_TEXTURE_LOD_BIAS. When target is GL_POINT_SPRITE, pname must be
GL_COORD_REPLACE. When target is GL_TEXTURE_ENV, pname can be GL_TEXTURE_ENV_MODE, GL_TEXTURE_ENV_COLOR, GL_COMBINE_RGB, GL_COMBINE_ALPHA,
GL_RGB_SCALE, GL_ALPHA_SCALE, GL_SRC0_RGB, GL_SRC1_RGB, GL_SRC2_RGB, GL_SRC0_ALPHA, GL_SRC1_ALPHA, or GL_SRC2_ALPHA.
pname names a specific texture environment parameter, as follows:
GL_TEXTURE_ENV_MODE
params returns the single-valued texture environment mode, a symbolic constant. The initial value is GL_MODULATE.
GL_TEXTURE_ENV_COLOR
params 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 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).
GL_TEXTURE_LOD_BIAS
params returns a single floating-point value that is the texture level-of-detail bias. The initial value is 0.
GL_COMBINE_RGB
params returns a single symbolic constant value representing the current RGB combine mode. The initial value is GL_MODULATE.
GL_COMBINE_ALPHA
params returns a single symbolic constant value representing the current alpha combine mode. The initial value is GL_MODULATE.
GL_SRC0_RGB
params returns a single symbolic constant value representing the texture combiner zero's RGB source. The initial value is GL_TEXTURE.
GL_SRC1_RGB
params returns a single symbolic constant value representing the texture combiner one's RGB source. The initial value is GL_PREVIOUS.
GL_SRC2_RGB
params returns a single symbolic constant value representing the texture combiner two's RGB source. The initial value is GL_CONSTANT.
GL_SRC0_ALPHA
params returns a single symbolic constant value representing the texture combiner zero's alpha source. The initial value is GL_TEXTURE.
GL_SRC1_ALPHA
params returns a single symbolic constant value representing the texture combiner one's alpha source. The initial value is GL_PREVIOUS.
GL_SRC2_ALPHA
params returns a single symbolic constant value representing the texture combiner two's alpha source. The initial value is GL_CONSTANT.
GL_OPERAND0_RGB
params returns a single symbolic constant value representing the texture combiner zero's RGB operand. The initial value is
GL_SRC_COLOR.
GL_OPERAND1_RGB
params returns a single symbolic constant value representing the texture combiner one's RGB operand. The initial value is GL_SRC_COLOR.
GL_OPERAND2_RGB
params returns a single symbolic constant value representing the texture combiner two's RGB operand. The initial value is GL_SRC_ALPHA.
GL_OPERAND0_ALPHA
params returns a single symbolic constant value representing the texture combiner zero's alpha operand. The initial value is
GL_SRC_ALPHA.
GL_OPERAND1_ALPHA
params returns a single symbolic constant value representing the texture combiner one's alpha operand. The initial value is
GL_SRC_ALPHA.
GL_OPERAND2_ALPHA
params returns a single symbolic constant value representing the texture combiner two's alpha operand. The initial value is
GL_SRC_ALPHA.
GL_RGB_SCALE
params returns a single floating-point value representing the current RGB texture combiner scaling factor. The initial value is 1.0.
GL_ALPHA_SCALE
params returns a single floating-point value representing the current alpha texture combiner scaling factor. The initial value is 1.0.
GL_COORD_REPLACE
params returns a single boolean value representing the current point sprite texture coordinate replacement enable state. The initial
value is GL_FALSE.
NOTES
If an error is generated, no change is made to the contents of params.
For OpenGL versions 1.3 and greater, or when the ARB_multitexture extension is supported, glGetTexEnv returns the texture environment
parameters for the active texture unit.
GL_COMBINE_RGB, GL_COMBINE_ALPHA, GL_SRC0_RGB, GL_SRC1_RGB, GL_SRC2_RGB, GL_SRC0_ALPHA, GL_SRC1_ALPHA, GL_SRC2_ALPHA, GL_OPERAND0_RGB,
GL_OPERAND1_RGB, GL_OPERAND2_RGB, GL_OPERAND0_ALPHA, GL_OPERAND1_ALPHA, GL_OPERAND2_ALPHA, GL_RGB_SCALE, and GL_ALPHA_SCALE are available
only if the GL version is 1.3 or greater.
GL_TEXTURE_FILTER_CONTROL and GL_TEXTURE_LOD_BIAS are available only if the GL version is 1.4 or greater.
GL_POINT_SPRITE and GL_COORD_REPLACE are available only if the GL version is 2.0 or greater.
ERRORS
GL_INVALID_ENUM is generated if target or pname is not an accepted value.
GL_INVALID_OPERATION is generated if glGetTexEnv is executed between the execution of glBegin() and the corresponding execution of glEnd().
SEE ALSO
glActiveTexture(), glTexEnv()
COPYRIGHT
Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.
AUTHORS
opengl.org
opengl.org 06/10/2014 GLGETTEXENV(3G)