GLMINMAX(3G) UNIX Programmer's Manual GLMINMAX(3G)
NAME
glMinmax - define minmax table
C SPECIFICATION
void glMinmax( GLenum target,
GLenum internalformat,
GLboolean sink )
PARAMETERS
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_LUMINANCE_ALPHA, GL_LUMINANCE4_ALPHA4,
GL_LUMINANCE6_ALPHA2, GL_LUMINANCE8_ALPHA8,
GL_LUMINANCE12_ALPHA4,
GL_LUMINANCE12_ALPHA12,
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.
DESCRIPTION
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.
NOTES
glMinmax is present only if GL_ARB_imaging is returned when
glGetString is called with an argument of GL_EXTENSIONS.
ERRORS
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.
ASSOCIATED GETS
glGetMinmaxParameter
SEE ALSO
glGetMinmax(3G), glResetMinmax(3G)
MirBSD #10-current Printed 2021-12-07 2