glGetTexEnv

return texture environment parameters

Signature

glGetTexEnv( )->
glGetTexEnvfv( GLenum ( target ) , GLenum ( pname ) , GLfloat * ( params ) )-> void
glGetTexEnvfv( target , pname , params )
glGetTexEnviv( GLenum ( target ) , GLenum ( pname ) , GLint * ( params ) )-> void
glGetTexEnviv( target , pname , params )

Parameters

VariablesDescription
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 Notices

This documentation is based on documentation licensed under the SGI Free Software License B.

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