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glGetMaterialfv, glGetMaterialiv - return material parameters
void glGetMaterialfv( GLenum face,
GLenum pname,
GLfloat *params )
void glGetMaterialiv( GLenum face,
GLenum pname,
GLint *params )
eqn not supported
- 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
-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.
If an
error is generated, no change is made to the contents of params.
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.
glMaterial(3G)
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