glGetMaterial(3) glGetMaterial(3)
NAME
glGetMaterialfv, glGetMaterialiv - 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, 1.0], 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. (All the
other parameters are used only for RGBA light-
ing.) Integer values, when requested, are com-
puted 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(3)
glGetMaterial(3)
Mac OS X 10.6 - Generated Thu Sep 17 20:20:21 CDT 2009