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# docs.GL

OpenGL 3
OpenGL 2

# glGetTexGen

## 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 https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/.

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