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GLMATERIAL(3G)                                                                                GLMATERIAL(3G)



NAME
       glMaterialf,  glMateriali,  glMaterialfv, glMaterialiv - specify material parameters for the lighting
       model


C SPECIFICATION
       void glMaterialf( GLenum face,
                         GLenum pname,
                         GLfloat param )
       void glMateriali( GLenum face,
                         GLenum pname,
                         GLint param )


PARAMETERS
       face    Specifies which face or faces are being updated.   Must  be  one  of  GL_FRONT,  GL_BACK,  or
               GL_FRONT_AND_BACK.

       pname   Specifies  the  single-valued  material parameter of the face or faces that is being updated.
               Must be GL_SHININESS.

       param   Specifies the value that parameter GL_SHININESS will be set to.

C SPECIFICATION
       void glMaterialfv( GLenum face,
                          GLenum pname,
                          const GLfloat *params )
       void glMaterialiv( GLenum face,
                          GLenum pname,
                          const GLint *params )


PARAMETERS
       face   Specifies which face or faces are being  updated.   Must  be  one  of  GL_FRONT,  GL_BACK,  or
              GL_FRONT_AND_BACK.

       pname  Specifies  the  material parameter of the face or faces that is being updated.  Must be one of
              GL_AMBIENT, GL_DIFFUSE, GL_SPECULAR, GL_EMISSION,  GL_SHININESS,  GL_AMBIENT_AND_DIFFUSE,   or
              GL_COLOR_INDEXES.

       params Specifies a pointer to the value or values that pname will be set to.

DESCRIPTION
       glMaterial assigns values to material parameters.  There are two matched sets of material parameters.
       One, the front-facing set, is used to shade points, lines, bitmaps, and all polygons (when  two-sided
       lighting is disabled), or just front-facing polygons (when two-sided lighting is enabled).  The other
       set, back-facing, is used to shade back-facing polygons only  when  two-sided  lighting  is  enabled.
       Refer  to the glLightModel reference page for details concerning one- and two-sided lighting calcula-tions. calculations.
       tions.

       glMaterial takes three arguments.  The first, face, specifies whether  the  GL_FRONT  materials,  the
       GL_BACK  materials,  or both GL_FRONT_AND_BACK materials will be modified.  The second, pname, speci-fies specifies
       fies which of several parameters in one or both sets will be modified.  The third, params,  specifies
       what value or values will be assigned to the specified parameter.

       Material parameters are used in the lighting equation that is optionally applied to each vertex.  The
       equation is discussed in the glLightModel reference page.  The parameters that can be specified using
       glMaterial, and their interpretations by the lighting equation, are as follows:

       GL_AMBIENT          params  contains  four  integer or floating-point values that specify the ambient
                           RGBA reflectance of the material.  Integer values are mapped linearly  such  that
                           the  most  positive representable value maps to 1.0, and the most negative repre-sentable representable
                           sentable value maps to -1.0.  Floating-point values are mapped directly.  Neither
                           integer  nor  floating-point values are clamped.  The initial ambient reflectance
                           for both front- and back-facing materials is (0.2, 0.2, 0.2, 1.0).

       GL_DIFFUSE          params contains four integer or floating-point values that  specify  the  diffuse
                           RGBA  reflectance  of the material.  Integer values are mapped linearly such that
                           the most positive representable value maps to 1.0, and the most  negative  repre-sentable representable
                           sentable value maps to -1.0.  Floating-point values are mapped directly.  Neither
                           integer nor floating-point values are clamped.  The initial  diffuse  reflectance
                           for both front- and back-facing materials is (0.8, 0.8, 0.8, 1.0).

       GL_SPECULAR         params  contains  four integer or floating-point values that specify the specular
                           RGBA reflectance of the material.  Integer values are mapped linearly  such  that
                           the  most  positive representable value maps to 1.0, and the most negative repre-sentable representable
                           sentable value maps to -1.0.  Floating-point values are mapped directly.  Neither
                           integer  nor floating-point values are clamped.  The initial specular reflectance
                           for both front- and back-facing materials is (0, 0, 0, 1).

       GL_EMISSION         params contains four integer or floating-point values that specify the RGBA emit-ted emitted
                           ted  light  intensity  of  the material.  Integer values are mapped linearly such
                           that the most positive representable value maps to 1.0,  and  the  most  negative
                           representable  value  maps  to  -1.0.  Floating-point values are mapped directly.
                           Neither integer nor floating-point values  are  clamped.   The  initial  emission
                           intensity for both front- and back-facing materials is (0, 0, 0, 1).

       GL_SHININESS        params is a single integer or floating-point value that specifies the RGBA specu-lar specular
                           lar exponent of the material.   Integer  and  floating-point  values  are  mapped
                           directly.   Only  values in the range [0,128] are accepted.  The initial specular
                           exponent for both front- and back-facing materials is 0.

       GL_AMBIENT_AND_DIFFUSE
                           Equivalent to calling glMaterial twice with the same parameter values, once  with
                           GL_AMBIENT and once with GL_DIFFUSE.

       GL_COLOR_INDEXES    params  contains  three  integer  or  floating-point  values specifying the color
                           indices for ambient, diffuse, and specular lighting.   These  three  values,  and
                           GL_SHININESS,  are the only material values used by the color index mode lighting
                           equation.  Refer to the glLightModel reference page for  a  discussion  of  color
                           index lighting.

NOTES
       The  material parameters can be updated at any time.  In particular, glMaterial can be called between
       a call to glBegin and the corresponding call to glEnd.  If only a single material parameter is to  be
       changed per vertex, however, glColorMaterial is preferred over glMaterial (see glColorMaterial).

       While the ambient, diffuse, specular and emission material parameters all have alpha components, only
       the diffuse alpha component is used in the lighting computation.

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

       GL_INVALID_VALUE is generated if a specular exponent outside the range [0,128] is specified.

ASSOCIATED GETS
       glGetMaterial

SEE ALSO
       glColorMaterial(3G), glLight(3G), glLightModel(3G)




                                                                                              GLMATERIAL(3G)