Name
glGetMaterialfv, glGetMaterialiv — return material parameters
C Specification
void glGetMaterialfv
| ( | GLenum face
, GLenum pname
, GLfloat *params
); |
void glGetMaterialiv
| ( | GLenum face
, GLenum pname
, GLint *params
); |
Python Specification
glGetMaterialfv
| ( |
face
,
pname
) →
params
|
glGetMaterialiv
| ( |
face
,
pname
) →
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 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 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.