121 lines
3.6 KiB
Plaintext
121 lines
3.6 KiB
Plaintext
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'\" t
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'\"! tbl | 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 minmax.gl
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.ds Xs 45595 6 minmax.gl
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.TH GLMINMAX 3G
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.SH NAME
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.B "glMinmax
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\- define minmax table
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.SH C SPECIFICATION
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void \f3glMinmax\fP(
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GLenum \fItarget\fP,
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.nf
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.ta \w'\f3void \fPglMinmax( 'u
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GLenum \fIinternalformat\fP,
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GLboolean \fIsink\fP )
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.fi
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.SH PARAMETERS
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.TP \w'\fIinternalformat\fP\ \ 'u
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\f2target\fP
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The minmax table whose parameters are to be set.
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Must be
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\%\f3GL_MINMAX\fP.
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.TP
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\f2internalformat\fP
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The of entries in the minmax table.
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Must be one of
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\%\f3GL_ALPHA\fP,
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\%\f3GL_ALPHA4\fP,
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\%\f3GL_ALPHA8\fP,
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\%\f3GL_ALPHA12\fP,
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\%\f3GL_ALPHA16\fP,
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\%\f3GL_LUMINANCE\fP,
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\%\f3GL_LUMINANCE4\fP,
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\%\f3GL_LUMINANCE8\fP,
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\%\f3GL_LUMINANCE12\fP,
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\%\f3GL_LUMINANCE16\fP,
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\%\f3GL_LUMINANCE_ALPHA\fP,
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\%\f3GL_LUMINANCE4_ALPHA4\fP,
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\%\f3GL_LUMINANCE6_ALPHA2\fP,
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\%\f3GL_LUMINANCE8_ALPHA8\fP,
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\%\f3GL_LUMINANCE12_ALPHA4\fP,
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\%\f3GL_LUMINANCE12_ALPHA12\fP,
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\%\f3GL_LUMINANCE16_ALPHA16\fP,
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\%\f3GL_R3_G3_B2\fP,
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\%\f3GL_RGB\fP,
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\%\f3GL_RGB4\fP,
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\%\f3GL_RGB5\fP,
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\%\f3GL_RGB8\fP,
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\%\f3GL_RGB10\fP,
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\%\f3GL_RGB12\fP,
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\%\f3GL_RGB16\fP,
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\%\f3GL_RGBA\fP,
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\%\f3GL_RGBA2\fP,
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\%\f3GL_RGBA4\fP,
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\%\f3GL_RGB5_A1\fP,
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\%\f3GL_RGBA8\fP,
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\%\f3GL_RGB10_A2\fP,
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\%\f3GL_RGBA12\fP, or
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\%\f3GL_RGBA16\fP.
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.TP
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\f2sink\fP
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If \%\f3GL_TRUE\fP, pixels will be consumed by the minmax
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process and no drawing or texture loading will take place.
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If \%\f3GL_FALSE\fP, pixels will proceed to the final conversion process after
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minmax.
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.SH DESCRIPTION
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When \%\f3GL_MINMAX\fP is enabled, the RGBA components of incoming pixels are
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compared to the minimum and maximum values for each component, which are
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stored in the 2-element minmax table.
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(The first element stores the minima, and the second element stores
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the maxima.)
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If a pixel component is greater than the corresponding component
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in the maximum element, then the maximum element is updated with the
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pixel component value.
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If a pixel component is less than the corresponding component in
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the minimum element, then the minimum element is updated with the
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pixel component value.
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(In both cases, if the internal of the minmax table includes
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luminance, then the R color component of incoming pixels is used
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for comparison.)
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The contents of the minmax table may be retrieved at a later time
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by calling \%\f3glGetMinmax\fP.
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The minmax operation is enabled or disabled by calling \%\f3glEnable\fP or
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\%\f3glDisable\fP, respectively, with an argument of \%\f3GL_MINMAX\fP.
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.P
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\%\f3glMinmax\fP redefines the current minmax table to have entries of the
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specified by \f2internalformat\fP.
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The maximum element is initialized with the smallest possible component
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values, and the minimum element is initialized with the largest possible
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component values.
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The values in the previous minmax table, if any, are lost.
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If \f2sink\fP is \%\f3GL_TRUE\fP, then pixels are discarded after minmax;
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no further processing of the pixels takes place, and no drawing,
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texture loading, or pixel readback will result.
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.P
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.SH NOTES
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\%\f3glMinmax\fP is present only if \%\f3GL_ARB_imaging\fP is returned when \%\f3glGetString\fP
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is called with an argument of \%\f3GL_EXTENSIONS\fP.
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.SH ERRORS
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\%\f3GL_INVALID_ENUM\fP is generated if \f2target\fP is not one of the allowable
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values.
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.P
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\%\f3GL_INVALID_ENUM\fP is generated if \f2internalformat\fP is not one of the
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allowable values.
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.P
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\%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glMinmax\fP is executed
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between the execution of \%\f3glBegin\fP and the corresponding
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execution of \%\f3glEnd\fP.
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.SH ASSOCIATED GETS
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\%\f3glGetMinmaxParameter\fP
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.SH SEE ALSO
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\%\f3glGetMinmax(3G)\fP,
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\%\f3glResetMinmax(3G)\fP
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