MirOS Manual: glGetMaterial(3), glGetMaterialfv(3), glGetMaterialiv(3)


GLGETMATERIAL(3G)   UNIX Programmer's Manual    GLGETMATERIAL(3G)

NAME

     glGetMaterialfv, glGetMaterialiv - return material parame-
     ters

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, respec-
             tively.

     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 represent-
                           able 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

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GLGETMATERIAL(3G)   UNIX Programmer's Manual    GLGETMATERIAL(3G)

                           that 1.0 maps to the most positive
                           representable integer value, and -1.0
                           maps to the most negative represent-
                           able 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 represent-
                           able 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 represen-
                           tation 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, 1.0], 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.

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GLGETMATERIAL(3G)   UNIX Programmer's Manual    GLGETMATERIAL(3G)

                           (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 exe-
     cuted between the execution of glBegin and the corresponding
     execution of glEnd.

SEE ALSO

     glMaterial(3G)

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