glMaterialfv function

Article
12/11/2020

The glMaterialfv function specifies material parameters for the lighting model.

Syntax

void WINAPI glMaterialfv(
         GLenum  face,
         GLenum  pname,
   const GLfloat *params
);

Parameters

face

The face or faces that are being updated. Must be one of the following: GL_FRONT, GL_BACK, or GL_FRONT and GL_BACK.

pname

The material parameter of the face or faces being updated. The parameters that can be specified using glMaterialfv, and their interpretations by the lighting equation, are as follows.

Value	Meaning
GL_AMBIENT	The params parameter contains four 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 default ambient reflectance for both front-facing and back-facing materials is (0.2, 0.2, 0.2, 1.0).
GL_DIFFUSE	The params parameter contains four 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 default diffuse reflectance for both front-facing and back-facing materials is (0.8, 0.8, 0.8, 1.0).
GL_SPECULAR	The params parameter contains four 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 default specular reflectance for both front-facing and back-facing materials is (0.0, 0.0, 0.0, 1.0).
GL_EMISSION	The params parameter contains four 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 default emission intensity for both front-facing and back-facing materials is (0.0, 0.0, 0.0, 1.0).
GL_SHININESS	The param parameter is a single integer value that specifies the RGBA specular exponent of the material. Integer values are mapped directly. Only values in the range [0, 128] are accepted. The default specular exponent for both front-facing 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	The params parameter contains three floating-point values specifying the color indexes 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 glLightModel for a discussion of color-index lighting.

params

The value to which parameter GL_SHININESS will be set.

Return value

This function does not return a value.

Error codes

The following error codes can be retrieved by the glGetError function.

Name	Meaning
GL_INVALID_ENUM	Either face or pname was not an accepted value.
GL_INVALID_VALUE	A specular exponent outside the range of [0, 128] was specified.

Remarks

The glMaterialfv function 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 glLightModel for details concerning one-sided and two-sided lighting calculations.

The glMaterialfv function 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, param, specifies what value 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 glLightModel.

The material parameters can be updated at any time. In particular, glMaterialfv 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 glMaterialfv.

The following function retrieves information related to glMaterialfv:

glGetMaterial

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Header	Gl.h
Library	Opengl32.lib
DLL	Opengl32.dll

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