108 lines
3.2 KiB
Plaintext
108 lines
3.2 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 rendermod
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.ds Xs 54049 5 rendermode.gl
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.TH GLRENDERMODE 3G
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.SH NAME
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.B "glRenderMode
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\- set rasterization mode
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.SH C SPECIFICATION
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GLint \f3glRenderMode\fP(
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GLenum \fImode\fP )
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.nf
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.fi
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.SH PARAMETERS
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.TP \w'\f2mode\fP\ \ 'u
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\f2mode\fP
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Specifies the rasterization mode.
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Three values are accepted:
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\%\f3GL_RENDER\fP,
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\%\f3GL_SELECT\fP, and
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\%\f3GL_FEEDBACK\fP.
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The initial value is \%\f3GL_RENDER\fP.
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.SH DESCRIPTION
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\%\f3glRenderMode\fP sets the rasterization mode.
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It takes one argument,
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\f2mode\fP,
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which can assume one of three predefined values:
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.TP 16
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\%\f3GL_RENDER\fP
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Render mode. Primitives are rasterized,
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producing pixel fragments,
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which are written into the frame buffer.
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This is the normal mode
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and also the default mode.
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.TP
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\%\f3GL_SELECT\fP
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Selection mode.
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No pixel fragments are produced,
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and no change to the frame buffer contents is made.
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Instead,
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a record of the names of primitives that would have been drawn
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if the render mode had been \%\f3GL_RENDER\fP is returned in a select buffer,
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which must be created (see \%\f3glSelectBuffer\fP) before selection mode
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is entered.
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.TP
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\%\f3GL_FEEDBACK\fP
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Feedback mode.
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No pixel fragments are produced,
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and no change to the frame buffer contents is made.
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Instead,
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the coordinates and attributes of vertices that would have been drawn
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if the render mode had been \%\f3GL_RENDER\fP is returned in a feedback buffer,
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which must be created (see \%\f3glFeedbackBuffer\fP) before feedback mode
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is entered.
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.P
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The return value of \%\f3glRenderMode\fP is determined by the render mode at the time
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\%\f3glRenderMode\fP is called,
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rather than by \f2mode\fP.
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The values returned for the three render modes are as follows:
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.TP 16
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\%\f3GL_RENDER\fP
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0.
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.TP
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\%\f3GL_SELECT\fP
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The number of hit records transferred to the select buffer.
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.TP
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\%\f3GL_FEEDBACK\fP
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The number of values (not vertices) transferred to the feedback buffer.
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.P
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See the \%\f3glSelectBuffer\fP and \%\f3glFeedbackBuffer\fP reference pages for
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more details concerning selection and feedback operation.
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.SH NOTES
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If an error is generated,
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\%\f3glRenderMode\fP returns 0 regardless of the current render mode.
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.SH ERRORS
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\%\f3GL_INVALID_ENUM\fP is generated if \f2mode\fP is not one of the three
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accepted values.
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.P
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\%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glSelectBuffer\fP is called
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while the render mode is \%\f3GL_SELECT\fP,
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or if \%\f3glRenderMode\fP is called with argument \%\f3GL_SELECT\fP before
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\%\f3glSelectBuffer\fP is called at least once.
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.P
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\%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glFeedbackBuffer\fP is called
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while the render mode is \%\f3GL_FEEDBACK\fP,
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or if \%\f3glRenderMode\fP is called with argument \%\f3GL_FEEDBACK\fP before
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\%\f3glFeedbackBuffer\fP is called at least once.
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.P
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\%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glRenderMode\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_RENDER_MODE\fP
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.SH SEE ALSO
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\%\f3glFeedbackBuffer(3G)\fP,
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\%\f3glInitNames(3G)\fP,
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\%\f3glLoadName(3G)\fP,
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\%\f3glPassThrough(3G)\fP,
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\%\f3glPushName(3G)\fP,
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\%\f3glSelectBuffer(3G)\fP
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