89 lines
2.4 KiB
Plaintext
89 lines
2.4 KiB
Plaintext
|
'\" te
|
||
|
|
'\"! tbl|eqn | mmdoc
|
||
|
|
'\"macro stdmacro
|
||
|
|
.ds Vn Version 1.2
|
||
|
|
.ds Dt 24 September 1999
|
||
|
|
.ds Re Release 1.2.1
|
||
|
|
.ds Dp Jan 14 18:30
|
||
|
|
.ds Dm 01 depthfunc
|
||
|
|
.ds Xs 34310 5 depthfunc.gl
|
||
|
|
.TH GLDEPTHFUNC 3G
|
||
|
|
.SH NAME
|
||
|
|
.B "glDepthFunc
|
||
|
|
\- specify the value used for depth buffer comparisons
|
||
|
|
|
||
|
|
.SH C SPECIFICATION
|
||
|
|
void \f3glDepthFunc\fP(
|
||
|
|
GLenum \fIfunc\fP )
|
||
|
|
.nf
|
||
|
|
.fi
|
||
|
|
|
||
|
|
.SH PARAMETERS
|
||
|
|
.TP \w'\f2func\fP\ \ 'u
|
||
|
|
\f2func\fP
|
||
|
|
Specifies the depth comparison function.
|
||
|
|
Symbolic constants
|
||
|
|
\%\f3GL_NEVER\fP,
|
||
|
|
\%\f3GL_LESS\fP,
|
||
|
|
\%\f3GL_EQUAL\fP,
|
||
|
|
\%\f3GL_LEQUAL\fP,
|
||
|
|
\%\f3GL_GREATER\fP,
|
||
|
|
\%\f3GL_NOTEQUAL\fP,
|
||
|
|
\%\f3GL_GEQUAL\fP, and
|
||
|
|
\%\f3GL_ALWAYS\fP are accepted.
|
||
|
|
The initial value is \%\f3GL_LESS\fP.
|
||
|
|
.SH DESCRIPTION
|
||
|
|
\%\f3glDepthFunc\fP specifies the function used to compare each incoming pixel depth value
|
||
|
|
with the depth value present in the depth buffer.
|
||
|
|
The comparison is performed only if depth testing is enabled.
|
||
|
|
(See \%\f3glEnable\fP and \%\f3glDisable\fP of \%\f3GL_DEPTH_TEST\fP.)
|
||
|
|
.P
|
||
|
|
\f2func\fP specifies the conditions under which the pixel will be drawn.
|
||
|
|
The comparison functions are as follows:
|
||
|
|
.TP 16
|
||
|
|
\%\f3GL_NEVER\fP
|
||
|
|
Never passes.
|
||
|
|
.TP
|
||
|
|
\%\f3GL_LESS\fP
|
||
|
|
Passes if the incoming depth value is less than the stored depth value.
|
||
|
|
.TP
|
||
|
|
\%\f3GL_EQUAL\fP
|
||
|
|
Passes if the incoming depth value is equal to the stored depth value.
|
||
|
|
.TP
|
||
|
|
\%\f3GL_LEQUAL\fP
|
||
|
|
Passes if the incoming depth value is less than or equal to
|
||
|
|
the stored depth value.
|
||
|
|
.TP
|
||
|
|
\%\f3GL_GREATER\fP
|
||
|
|
Passes if the incoming depth value is greater than the stored depth value.
|
||
|
|
.TP
|
||
|
|
\%\f3GL_NOTEQUAL\fP
|
||
|
|
Passes if the incoming depth value is not equal to the stored depth value.
|
||
|
|
.TP
|
||
|
|
\%\f3GL_GEQUAL\fP
|
||
|
|
Passes if the incoming depth value is greater than or equal to
|
||
|
|
the stored depth value.
|
||
|
|
.TP
|
||
|
|
\%\f3GL_ALWAYS\fP
|
||
|
|
Always passes.
|
||
|
|
.P
|
||
|
|
The initial value of \f2func\fP is \%\f3GL_LESS\fP.
|
||
|
|
Initially, depth testing is disabled.
|
||
|
|
.NOTES
|
||
|
|
Even if the depth buffer exists and the depth mask is non-zero, the
|
||
|
|
depth buffer is not updated if the depth test is disabled.
|
||
|
|
.SH ERRORS
|
||
|
|
\%\f3GL_INVALID_ENUM\fP is generated if \f2func\fP is not an accepted value.
|
||
|
|
.P
|
||
|
|
\%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glDepthFunc\fP
|
||
|
|
is executed between the execution of \%\f3glBegin\fP
|
||
|
|
and the corresponding execution of \%\f3glEnd\fP.
|
||
|
|
.SH ASSOCIATED GETS
|
||
|
|
\%\f3glGet\fP with argument \%\f3GL_DEPTH_FUNC\fP
|
||
|
|
.br
|
||
|
|
\%\f3glIsEnabled\fP with argument \%\f3GL_DEPTH_TEST\fP
|
||
|
|
.SH SEE ALSO
|
||
|
|
\%\f3glDepthRange(3G)\fP,
|
||
|
|
\%\f3glEnable(3G)\fP,
|
||
|
|
\%\f3glPolygonOffset(3G)\fP
|