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<STRONG>NAME</STRONG>
<STRONG>glMaterialf,</STRONG> <STRONG>glMateriali,</STRONG> <STRONG>glMaterialfv,</STRONG> <STRONG>glMaterialiv</STRONG> -
specify material parameters for the lighting model
<STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>
void <STRONG>glMaterialf</STRONG>( GLenum <EM>face</EM>,
GLenum <EM>pname</EM>,
GLfloat <EM>param</EM> )
void <STRONG>glMateriali</STRONG>( GLenum <EM>face</EM>,
GLenum <EM>pname</EM>,
GLint <EM>param</EM> )
<STRONG>PARAMETERS</STRONG>
<EM>face</EM> Specifies which face or faces are being updated.
Must be one of <STRONG>GL_FRONT</STRONG>, <STRONG>GL_BACK</STRONG>, or
<STRONG>GL_FRONT_AND_BACK</STRONG>.
<EM>pname</EM> Specifies the single-valued material parameter of
the face or faces that is being updated. Must be
<STRONG>GL_SHININESS</STRONG>.
<EM>param</EM> Specifies the value that parameter <STRONG>GL_SHININESS</STRONG> will
be set to.
<STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>
void <STRONG>glMaterialfv</STRONG>( GLenum <EM>face</EM>,
GLenum <EM>pname</EM>,
const GLfloat *<EM>params</EM> )
void <STRONG>glMaterialiv</STRONG>( GLenum <EM>face</EM>,
GLenum <EM>pname</EM>,
const GLint *<EM>params</EM> )
<STRONG>PARAMETERS</STRONG>
<EM>face</EM> Specifies which face or faces are being updated. Must
be one of <STRONG>GL_FRONT</STRONG>, <STRONG>GL_BACK</STRONG>, or <STRONG>GL_FRONT_AND_BACK</STRONG>.
<EM>pname</EM>
Specifies the material parameter of the face or faces
that is being updated. Must be one of <STRONG>GL_AMBIENT</STRONG>,
<STRONG>GL_DIFFUSE</STRONG>, <STRONG>GL_SPECULAR</STRONG>, <STRONG>GL_EMISSION</STRONG>, <STRONG>GL_SHININESS</STRONG>,
<STRONG>GL_AMBIENT_AND_DIFFUSE</STRONG>, or <STRONG>GL_COLOR_INDEXES</STRONG>.
<EM>params</EM>
Specifies a pointer to the value or values that <EM>pname</EM>
will be set to.
<STRONG>DESCRIPTION</STRONG>
<STRONG>glMaterial</STRONG> assigns values to material parameters. There are
two matched sets of material parameters. One, the <EM>front</EM>-
<EM>facing</EM> 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, <EM>back</EM>-<EM>facing</EM>, is used to shade back-facing
polygons only when two-sided lighting is enabled. Refer to
the <STRONG>glLightModel</STRONG> reference page for details concerning one-
and two-sided lighting calculations.
<STRONG>glMaterial</STRONG> takes three arguments. The first, <EM>face</EM>,
specifies whether the <STRONG>GL_FRONT</STRONG> materials, the <STRONG>GL_BACK</STRONG>
materials, or both <STRONG>GL_FRONT_AND_BACK</STRONG> materials will be
modified. The second, <EM>pname</EM>, specifies which of several
parameters in one or both sets will be modified. The third,
<EM>params</EM>, 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 <STRONG>glLightModel</STRONG> reference page. The
parameters that can be specified using <STRONG>glMaterial</STRONG>, and their
interpretations by the lighting equation, are as follows:
<STRONG>GL_AMBIENT</STRONG> <EM>params</EM> 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 representable 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).
<STRONG>GL_DIFFUSE</STRONG> <EM>params</EM> 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 representable 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).
<STRONG>GL_SPECULAR</STRONG> <EM>params</EM> 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 representable 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).
<STRONG>GL_EMISSION</STRONG> <EM>params</EM> contains four integer or
floating-point values that specify the
RGBA emitted 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).
<STRONG>GL_SHININESS</STRONG> <EM>params</EM> is a single integer or floating-
point value that specifies the RGBA
specular 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.
<STRONG>GL_AMBIENT_AND_DIFFUSE</STRONG>
Equivalent to calling <STRONG>glMaterial</STRONG> twice
with the same parameter values, once
with <STRONG>GL_AMBIENT</STRONG> and once with
<STRONG>GL_DIFFUSE</STRONG>.
<STRONG>GL_COLOR_INDEXES</STRONG> <EM>params</EM> contains three integer or
floating-point values specifying the
color indices for ambient, diffuse, and
specular lighting. These three values,
and <STRONG>GL_SHININESS</STRONG>, are the only material
values used by the color index mode
lighting equation. Refer to the
<STRONG>glLightModel</STRONG> reference page for a
discussion of color index lighting.
<STRONG>NOTES</STRONG>
The material parameters can be updated at any time. In
particular, <STRONG>glMaterial</STRONG> can be called between a call to
<STRONG>glBegin</STRONG> and the corresponding call to <STRONG>glEnd</STRONG>. If only a
single material parameter is to be changed per vertex,
however, <STRONG>glColorMaterial</STRONG> is preferred over <STRONG>glMaterial</STRONG> (see
<STRONG>glColorMaterial</STRONG>).
<STRONG>ERRORS</STRONG>
<STRONG>GL_INVALID_ENUM</STRONG> is generated if either <EM>face</EM> or <EM>pname</EM> is not
an accepted value.
<STRONG>GL_INVALID_VALUE</STRONG> is generated if a specular exponent outside
the range [0,128] is specified.
<STRONG>ASSOCIATED</STRONG> <STRONG>GETS</STRONG>
<STRONG>glGetMaterial</STRONG>
<STRONG>SEE</STRONG> <STRONG>ALSO</STRONG>
<STRONG>glColorMaterial</STRONG>, <STRONG>glLight</STRONG>, <STRONG>glLightModel</STRONG>
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