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
); |
Python Specification
glMaterialf
| ( |
face
,
pname
,
param
) →
None
|
glMateriali
| ( |
face
,
pname
,
param
) →
None
|
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
); |
Python Specification
glMaterialfv
| ( |
face
,
pname
,
params
) →
None
|
glMaterialiv
| ( |
face
,
pname
,
params
) →
None
|
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 calculations.
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, specifies
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 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).
-
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 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).
-
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 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).
-
GL_EMISSION
-
params 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).
-
GL_SHININESS
-
params 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.
-
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
Python Sample Code
- glMaterialf
- glMaterialfv
- OpenGL/Demo/GLUT/examples/molehill.py Ln#40,41,120,126,132...
- OpenGL/Demo/redbook/fog.py Ln#83,85,87
- OpenGL/Demo/redbook/teapots.py Ln#107,109,111
- OpenGL/Demo/tom/cone.py Ln#18,19,20,21
- OpenGL/Demo/tom/conechecker.py Ln#40,41,42,43
- OpenGL/Demo/tom/conesave.py Ln#22,23,24,25
- OpenGL/Demo/tom/demo.py Ln#91
- OpenGL/Demo/tom/fog.py Ln#67,68,69,70
- OpenGL/Demo/tom/pick.py Ln#24,26
- OpenGL/Demo/tom/text.py Ln#26
- OpenGL/Demo/twburton/knot.py Ln#193,195
- OpenGLContext/tests/redbook_alpha3D.py Ln#75,76,128,129,137...
- OpenGLContext/tests/redbook_surface.py Ln#62,63,64
- OpenGLContext/tests/redbook_surface_cb.py Ln#80,81,82
- OpenGLContext/tests/redbook_trim.py Ln#89,90,91
- GL_AMBIENT
- GL_DIFFUSE
- GL_EMISSION
- GL_FRONT
- OpenGL/Demo/GLUT/examples/molehill.py Ln#40,41,120,126,132...
- OpenGL/Demo/redbook/fog.py Ln#83,85,87,88
- OpenGL/Demo/redbook/teapots.py Ln#107,109,111,112
- OpenGL/Demo/tom/cone.py Ln#18,19,20,21
- OpenGL/Demo/tom/conechecker.py Ln#40,41,42,43
- OpenGL/Demo/tom/conesave.py Ln#22,23,24,25
- OpenGL/Demo/tom/demo.py Ln#91
- OpenGL/Demo/tom/fog.py Ln#67,68,69,70
- OpenGL/Demo/tom/pick.py Ln#24,26
- OpenGL/Demo/tom/text.py Ln#26
- OpenGL/Demo/twburton/knot.py Ln#192,193,195
- OpenGLContext/tests/redbook_alpha3D.py Ln#75,76,128,129,137...
- OpenGLContext/tests/redbook_surface.py Ln#62,63,64
- OpenGLContext/tests/redbook_surface_cb.py Ln#80,81,82
- OpenGLContext/tests/redbook_trim.py Ln#89,90,91
- GL_FRONT_AND_BACK
- GL_SHININESS
- GL_SPECULAR