104 lines
3.1 KiB
Plaintext
104 lines
3.1 KiB
Plaintext
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'\" 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 polygonmo
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.ds Xs 24991 5 polygonmode.gl
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.TH GLPOLYGONMODE 3G
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.SH NAME
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.B "glPolygonMode
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\- select a polygon rasterization mode
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.SH C SPECIFICATION
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void \f3glPolygonMode\fP(
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GLenum \fIface\fP,
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.nf
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.ta \w'\f3void \fPglPolygonMode( 'u
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GLenum \fImode\fP )
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.fi
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.SH PARAMETERS
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.TP \w'\f2face\fP\ \ 'u
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\f2face\fP
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Specifies the polygons that \f2mode\fP applies to.
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Must be
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\%\f3GL_FRONT\fP for front-facing polygons,
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\%\f3GL_BACK\fP for back-facing polygons,
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or \%\f3GL_FRONT_AND_BACK\fP for front- and back-facing polygons.
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.TP
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\f2mode\fP
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Specifies how polygons will be rasterized.
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Accepted values are
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\%\f3GL_POINT\fP,
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\%\f3GL_LINE\fP, and
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\%\f3GL_FILL\fP.
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The initial value is \%\f3GL_FILL\fP for both front- and back-facing polygons.
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.SH DESCRIPTION
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\%\f3glPolygonMode\fP controls the interpretation of polygons for rasterization.
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\f2face\fP describes which polygons \f2mode\fP applies to:
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front-facing polygons (\%\f3GL_FRONT\fP),
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back-facing polygons (\%\f3GL_BACK\fP),
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or both (\%\f3GL_FRONT_AND_BACK\fP).
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The polygon mode affects only the final rasterization of polygons.
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In particular,
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a polygon's vertices are lit and
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the polygon is clipped and possibly culled before these modes are applied.
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.P
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Three modes are defined and can be specified in \f2mode\fP:
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.TP 14
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\%\f3GL_POINT\fP
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Polygon vertices that are marked as the start of a boundary edge
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are drawn as points.
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Point attributes such as
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\%\f3GL_POINT_SIZE\fP and
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\%\f3GL_POINT_SMOOTH\fP control
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the rasterization of the points.
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Polygon rasterization attributes other than \%\f3GL_POLYGON_MODE\fP have no effect.
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.TP
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\%\f3GL_LINE\fP
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Boundary edges of the polygon are drawn as line segments.
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They are treated as connected line segments for line stippling;
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the line stipple counter and pattern are not reset between segments
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(see \%\f3glLineStipple\fP).
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Line attributes such as
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\%\f3GL_LINE_WIDTH\fP and
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\%\f3GL_LINE_SMOOTH\fP control
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the rasterization of the lines.
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Polygon rasterization attributes other than \%\f3GL_POLYGON_MODE\fP have no effect.
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.TP
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\%\f3GL_FILL\fP
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The interior of the polygon is filled.
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Polygon attributes such as
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\%\f3GL_POLYGON_STIPPLE\fP and
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\%\f3GL_POLYGON_SMOOTH\fP control the rasterization of the polygon.
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.SH EXAMPLES
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To draw a surface with filled back-facing polygons
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and outlined front-facing polygons,
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call
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.Ex 1
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glPolygonMode(\%\f3GL_FRONT\fP, \%\f3GL_LINE\fP);
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.Ee
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.SH NOTES
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Vertices are marked as boundary or nonboundary with an edge flag.
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Edge flags are generated internally by the GL when it decomposes
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polygons; they can be set explicitly using \%\f3glEdgeFlag\fP.
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.SH ERRORS
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\%\f3GL_INVALID_ENUM\fP is generated if either \f2face\fP or \f2mode\fP is not
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an accepted value.
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.P
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\%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glPolygonMode\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 ASSOCIATED GETS
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\%\f3glGet\fP with argument \%\f3GL_POLYGON_MODE\fP
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.SH SEE ALSO
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\%\f3glBegin(3G)\fP,
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\%\f3glEdgeFlag(3G)\fP,
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\%\f3glLineStipple(3G)\fP,
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\%\f3glLineWidth(3G)\fP,
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\%\f3glPointSize(3G)\fP,
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\%\f3glPolygonStipple(3G)\fP
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