GLGETTEXGEN(3G)

NAME
glGetTexGen - return texture coordinate generation parameters

C SPECIFICATION

void glGetTexGendv(GLenum coord, GLenum pname, GLdouble * params);

void glGetTexGenfv(GLenum coord, GLenum pname, GLfloat * params);

void glGetTexGeniv(GLenum coord, GLenum pname, GLint * params);

PARAMETERS

coord
    Specifies a texture coordinate. Must be GL_S, GL_T, GL_R, or GL_Q.

pname
    Specifies the symbolic name of the value(s) to be returned. Must be either GL_TEXTURE_GEN_MODE or the name of one of the texture generation plane equations: GL_OBJECT_PLANE or GL_EYE_PLANE.

params
    Returns the requested data.

DESCRIPTION

glGetTexGen returns in params selected parameters of a texture coordinate generation function that was specified using glTexGen(). coord names one of the (s, t, r, q) texture coordinates, using the symbolic constant GL_S, GL_T, GL_R, or GL_Q.

pname specifies one of three symbolic names:

GL_TEXTURE_GEN_MODE
    params returns the single-valued texture generation function, a symbolic constant. The initial value is GL_EYE_LINEAR.

GL_OBJECT_PLANE
    params returns the four plane equation coefficients that specify object linear-coordinate generation. Integer values, when requested, are mapped directly from the internal floating-point representation.

GL_EYE_PLANE
    params returns the four plane equation coefficients that specify eye linear-coordinate generation. Integer values, when requested, are mapped directly from the internal floating-point representation. The returned values are those maintained in eye coordinates. They are not equal to the values specified using glTexGen(), unless the modelview matrix was identity when glTexGen() was called.

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, glGetTexGen returns the texture coordinate generation parameters for the active texture unit.

ERRORS

GL_INVALID_ENUM is generated if coord or pname is not an accepted value.

GL_INVALID_OPERATION is generated if glGetTexGen is executed between the execution of glBegin() and the corresponding execution of glEnd().

SEE ALSO

glActiveTexture(), glTexGen()

COPYRIGHT

Copyright © 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/.