134 lines
4.3 KiB
Plaintext
134 lines
4.3 KiB
Plaintext
'\" e
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'\"! eqn | mmdoc
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'\"macro stdmacro
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.ds Vn Version 1.2
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.ds Dt 24 September 1999
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.ds Re Release 1.2.1
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.ds Dp Jan 14 18:30
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.ds Dm 01 getmateri
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.ds Xs 34280 6 getmaterial.gl
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.TH GLGETMATERIAL 3G
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.SH NAME
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.B "glGetMaterialfv, glGetMaterialiv
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\- return material parameters
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.SH C SPECIFICATION
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void \f3glGetMaterialfv\fP(
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GLenum \fIface\fP,
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.nf
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.ta \w'\f3void \fPglGetMaterialfv( 'u
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GLenum \fIpname\fP,
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GLfloat \fI*params\fP )
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.fi
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void \f3glGetMaterialiv\fP(
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GLenum \fIface\fP,
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.nf
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.ta \w'\f3void \fPglGetMaterialiv( 'u
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GLenum \fIpname\fP,
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GLint \fI*params\fP )
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.fi
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.EQ
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delim $$
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.EN
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.SH PARAMETERS
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.TP \w'\fIparams\fP\ \ 'u
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\f2face\fP
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Specifies which of the two materials is being queried.
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\%\f3GL_FRONT\fP or \%\f3GL_BACK\fP are accepted,
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representing the front and back materials, respectively.
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.TP
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\f2pname\fP
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Specifies the material parameter to return.
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\%\f3GL_AMBIENT\fP,
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\%\f3GL_DIFFUSE\fP,
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\%\f3GL_SPECULAR\fP,
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\%\f3GL_EMISSION\fP,
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\%\f3GL_SHININESS\fP, and
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\%\f3GL_COLOR_INDEXES\fP
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are accepted.
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.TP
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\f2params\fP
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Returns the requested data.
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.SH DESCRIPTION
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\%\f3glGetMaterial\fP returns in \f2params\fP the value or values of parameter \f2pname\fP
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of material \f2face\fP. Six parameters are defined:
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.TP 22
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\%\f3GL_AMBIENT\fP
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\f2params\fP returns four integer or floating-point values representing the
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ambient reflectance of the material.
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Integer values,
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when requested,
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are linearly mapped from the internal floating-point representation
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such that 1.0 maps to the most positive representable integer value,
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and \-1.0 maps to the most negative representable integer value.
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If the internal value is outside the range [\-1, 1],
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the corresponding integer return value is undefined. The initial value is
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(0.2, 0.2, 0.2, 1.0)
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.TP
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\%\f3GL_DIFFUSE\fP
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\f2params\fP returns four integer or floating-point values representing the
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diffuse reflectance of the material.
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Integer values,
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when requested,
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are linearly mapped from the internal floating-point representation
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such that 1.0 maps to the most positive representable integer value,
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and \-1.0 maps to the most negative representable integer value.
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If the internal value is outside the range [\-1, 1],
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the corresponding integer return value is undefined. The initial value is
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(0.8, 0.8, 0.8, 1.0).
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.TP
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\%\f3GL_SPECULAR\fP
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\f2params\fP returns four integer or floating-point values representing the
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specular reflectance of the material.
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Integer values,
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when requested,
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are linearly mapped from the internal floating-point representation
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such that 1.0 maps to the most positive representable integer value,
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and \-1.0 maps to the most negative representable integer value.
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If the internal value is outside the range [\-1, 1],
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the corresponding integer return value is undefined. The initial value is
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(0, 0, 0, 1).
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.TP
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\%\f3GL_EMISSION\fP
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\f2params\fP returns four integer or floating-point values representing the
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emitted light intensity of the material.
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Integer values,
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when requested,
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are linearly mapped from the internal floating-point representation
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such that 1.0 maps to the most positive representable integer value,
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and \-1.0 maps to the most negative representable integer value.
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If the internal value is outside the range [\-1, 1.0],
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the corresponding integer return value is undefined. The initial value is
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(0, 0, 0, 1).
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.TP
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\%\f3GL_SHININESS\fP
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\f2params\fP returns one integer or floating-point value representing the
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specular exponent of the material.
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Integer values,
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when requested,
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are computed by rounding the internal floating-point value to the
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nearest integer value. The initial value is 0.
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.TP
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\%\f3GL_COLOR_INDEXES\fP
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\f2params\fP returns three integer or floating-point values representing the
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ambient, diffuse, and specular indices of the material.
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These indices are used only for color index lighting.
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(All the other parameters are used only for RGBA lighting.)
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Integer values,
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when requested,
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are computed by rounding the internal floating-point values to the
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nearest integer values.
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.SH NOTES
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If an error is generated,
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no change is made to the contents of \f2params\fP.
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.SH ERRORS
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\%\f3GL_INVALID_ENUM\fP is generated if \f2face\fP or \f2pname\fP is not an
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accepted value.
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.P
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\%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glGetMaterial\fP
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is executed between the execution of \%\f3glBegin\fP
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and the corresponding execution of \%\f3glEnd\fP.
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.SH SEE ALSO
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\%\f3glMaterial(3G)\fP
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