GLGETMATERIAL() MachTen Programmer’s Manual GLGETMATERIAL()

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 )

delim $$

PARAMETERS
face Specifies which of the two materials is being
queried. GL_FRONT or GL_BACK are accepted, repre-
senting 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 mate-
rial. Integer values, when
requested, are linearly mapped from
the internal floating-point repre-
sentation 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 cor-
responding 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 mate-
rial. Integer values, when
requested, are linearly mapped from
the internal floating-point repre-
sentation 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 repre-
sentation 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 cor-
responding 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 repre-
sentation 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 float-
ing-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 con-
tents 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 corre-
sponding execution of glEnd.

SEE ALSO
glMaterial

MachTen 3