glGetMaterial — return material parameters
void glGetMaterialfv( | GLenum | face, |
GLenum | pname, | |
GLfloat * | params) ; |
void glGetMaterialiv( | GLenum | face, |
GLenum | pname, | |
GLint * | params) ; |
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.
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
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
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
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
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 lighting.)
Integer values,
when requested,
are computed by rounding the internal floating-point values to the
nearest integer values.
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.
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.