MirBSD manpage: glMinmax(3)

GLMINMAX(3G)        UNIX Programmer's Manual         GLMINMAX(3G)


     glMinmax - define minmax table


     void glMinmax( GLenum target,
                    GLenum internalformat,
                    GLboolean sink )


     target          The minmax table whose parameters are to be
                     set. Must be GL_MINMAX.

     internalformat  The  of entries in the minmax table. Must be
                     one of GL_ALPHA, GL_ALPHA4, GL_ALPHA8,
                     GL_ALPHA12, GL_ALPHA16, GL_LUMINANCE,
                     GL_LUMINANCE4, GL_LUMINANCE8,
                     GL_LUMINANCE12, GL_LUMINANCE16,
                     GL_LUMINANCE6_ALPHA2, GL_LUMINANCE8_ALPHA8,
                     GL_LUMINANCE16_ALPHA16, GL_R3_G3_B2, GL_RGB,
                     GL_RGB4, GL_RGB5, GL_RGB8, GL_RGB10,
                     GL_RGB12, GL_RGB16, GL_RGBA, GL_RGBA2,
                     GL_RGBA4, GL_RGB5_A1, GL_RGBA8, GL_RGB10_A2,
                     GL_RGBA12, or GL_RGBA16.

     sink            If GL_TRUE, pixels will be consumed by the
                     minmax process and no drawing or texture
                     loading will take place. If GL_FALSE, pixels
                     will proceed to the final conversion process
                     after minmax.


     When GL_MINMAX is enabled, the RGBA components of incoming
     pixels are compared to the minimum and maximum values for
     each component, which are stored in the 2-element minmax
     table. (The first element stores the minima, and the second
     element stores the maxima.) If a pixel component is greater
     than the corresponding component in the maximum element,
     then the maximum element is updated with the pixel component
     value. If a pixel component is less than the corresponding
     component in the minimum element, then the minimum element
     is updated with the pixel component value. (In both cases,
     if the internal  of the minmax table includes luminance,
     then the R color component of incoming pixels is used for
     comparison.) The contents of the minmax table may be
     retrieved at a later time by calling glGetMinmax. The minmax
     operation is enabled or disabled by calling glEnable or
     glDisable, respectively, with an argument of GL_MINMAX.

MirBSD #10-current     Printed 2021-12-07                       1

GLMINMAX(3G)        UNIX Programmer's Manual         GLMINMAX(3G)

     glMinmax redefines the current minmax table to have entries
     of the specified by internalformat. The maximum element is
     initialized with the smallest possible component values, and
     the minimum element is initialized with the largest possible
     component values. The values in the previous minmax table,
     if any, are lost. If sink is GL_TRUE, then pixels are dis-
     carded after minmax; no further processing of the pixels
     takes place, and no drawing, texture loading, or pixel read-
     back will result.


     glMinmax is present only if GL_ARB_imaging is returned when
     glGetString is called with an argument of GL_EXTENSIONS.


     GL_INVALID_ENUM is generated if target is not one of the
     allowable values.

     GL_INVALID_ENUM is generated if internalformat is not one of
     the allowable values.

     GL_INVALID_OPERATION is generated if glMinmax is executed
     between the execution of glBegin and the corresponding exe-
     cution of glEnd.




     glGetMinmax(3G), glResetMinmax(3G)

MirBSD #10-current     Printed 2021-12-07                       2

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