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# docs.GL

OpenGL 3
OpenGL 2

# glGetMaterial

## Name

glGetMaterial — return material parameters

## C Specification

`void glGetMaterialfv(` | GLenum | face,
| GLenum | pname,
| GLfloat * | params`)`;

`void glGetMaterialiv(` | GLenum | face,
| GLenum | pname,
| GLint * | params`)`;

## Parameters

`face`

  Specifies which of the two materials is being queried. `GL_FRONT` or `GL_BACK` are accepted, representing the front and back materials, respectively.

`pname`

  Specifies the material parameter to return. `GL_AMBIENT`, `GL_DIFFUSE`, `GL_SPECULAR`, `GL_EMISSION`, `GL_SHININESS`, and `GL_COLOR_INDEXES` are accepted.

`params`

  Returns the requested data.

## Description

`glGetMaterial` returns in `params` the value or values of parameter `pname` of material `face`. Six parameters are defined:

`GL_AMBIENT`

  `params` returns four integer or floating-point values representing the ambient reflectance of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range -1 1 , the corresponding integer return value is undefined. The initial value is (0.2, 0.2, 0.2, 1.0)

`GL_DIFFUSE`

  `params` returns four integer or floating-point values representing the diffuse reflectance of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range -1 1 , the corresponding integer return value is undefined. The initial value is (0.8, 0.8, 0.8, 1.0).

`GL_SPECULAR`

  `params` returns four integer or floating-point values representing the specular reflectance of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range -1 1 , the corresponding integer return value is undefined. The initial value is (0, 0, 0, 1).

`GL_EMISSION`

  `params` returns four integer or floating-point values representing the emitted light intensity of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range -1 1 , the corresponding integer return value is undefined. The initial value is (0, 0, 0, 1).

`GL_SHININESS`

  `params` returns one integer or floating-point value representing the specular exponent of the material. Integer values, when requested, are computed by rounding the internal floating-point value to the nearest integer value. The initial value is 0.

`GL_COLOR_INDEXES`

  `params` returns three integer or floating-point values representing the ambient, diffuse, and specular indices of the material. These indices are used only for color index lighting. (All the other parameters are used only for RGBA lighting.) Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer values.

## Notes

If an error is generated, no change is made to the contents of `params`.

## Errors

`GL_INVALID_ENUM` is generated if `face` or `pname` is not an accepted value.

`GL_INVALID_OPERATION` is generated if `glGetMaterial` is executed between the execution of glBegin and the corresponding execution of glEnd.

## See Also

glMaterial

## 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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