glGetMaterial Subroutine

OpenGL 1.1 for AIX: Reference Manual

glGetMaterial Subroutine

Purpose

Returns material parameters.

Library

OpenGL C bindings library: libGL.a

C Syntax

void glGetMaterialfv(GLenum Face,
        GLenum ParameterName,
        GLfloat *ParameterValues)

void glGetMaterialiv(GLenum Face,
        GLenum ParameterName,
        GLint *ParameterValues)

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.
ParameterName	Specifies the material parameter to return. GL_AMBIENT, GL_DIFFUSE, GL_SPECULAR, GL_EMISSION, GL_SHININESS, and GL_COLOR_INDEXES are accepted.
ParameterValues	Returns the requested data.

Description

The glGetMaterial subroutine returns in ParameterValues the value or values of parameter ParameterName of material Face. Six parameters are defined:

GL_AMBIENT	ParameterValues 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.
GL_DIFFUSE	ParameterValues 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.
GL_SPECULAR	ParameterValues 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.
GL_EMISSION	ParameterValues 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], the corresponding integer return value is undefined.
GL_SHININESS	ParameterValues 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.
GL_COLOR_INDEXES	ParameterValues 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. (The other parameters are all used only for red, green, blue, and alpha 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 ParameterValues.

Errors

GL_INVALID_ENUM	Either Face or ParameterName is not an accepted value.
GL_INVALID_OPERATION	The glGetMaterial subroutine is called between a call to glBegin and the corresponding call to glEnd.

Files

/usr/include/GL/gl.h

Contains C language constants, variable type definitions, and ANSI function prototypes for OpenGL.

Related Information

The glBegin or glEnd subroutine, glMaterial subroutine.

OpenGL Overview.