glGetTexEnv.3G man page

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()

Authors

opengl.org

Referenced By

glGetTexEnvfv.3G(3) and glGetTexEnviv.3G(3) are aliases of glGetTexEnv.3G(3).

02/04/2016 opengl.org OpenGL Manual