66 lines
1.9 KiB
Plaintext
66 lines
1.9 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 depthrang
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.ds Xs 41369 4 depthrange.gl
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.TH GLDEPTHRANGE 3G
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.SH NAME
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.B "glDepthRange
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\- specify mapping of depth values from normalized device coordinates to window coordinates
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.SH C SPECIFICATION
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void \f3glDepthRange\fP(
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GLclampd \fInear_val\fP,
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.nf
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.ta \w'\f3void \fPglDepthRange( 'u
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GLclampd \fIfar_val\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'\f2near_val\fP\ \ 'u
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\f2near_val\fP
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Specifies the mapping of the near clipping plane to window coordinates.
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The initial value is 0.
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.TP
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\f2far_val\fP
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Specifies the mapping of the far clipping plane to window coordinates.
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The initial value is 1.
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.SH DESCRIPTION
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After clipping and division by \f2w\fP,
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depth coordinates range from \-1 to 1,
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corresponding to the near and far clipping planes.
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\%\f3glDepthRange\fP specifies a linear mapping of the normalized depth coordinates
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in this range to window depth coordinates.
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Regardless of the actual depth buffer implementation,
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window coordinate depth values are treated as though they range
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from 0 through 1 (like color components).
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Thus,
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the values accepted by \%\f3glDepthRange\fP are both clamped to this range
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before they are accepted.
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.P
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The setting of (0,1) maps the near plane to 0 and
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the far plane to 1.
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With this mapping,
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the depth buffer range is fully utilized.
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.SH NOTES
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It is not necessary that \f2near_val\fP be less than \f2far_val\fP.
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Reverse mappings such as $"near_val" ~=~ 1$, and $"far_val" ~=~ 0$
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are acceptable.
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.SH ERRORS
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\%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glDepthRange\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_DEPTH_RANGE\fP
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.SH SEE ALSO
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\%\f3glDepthFunc(3G)\fP,
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\%\f3glPolygonOffset(3G)\fP,
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\%\f3glViewport(3G)\fP
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