fglGetMinmaxEXT(3G) OpenGL Reference fglGetMinmaxEXT(3G)NAME
fglGetMinmaxEXT - get minimum and maximum pixel values
FORTRAN SPECIFICATION
SUBROUTINE fglGetMinmaxEXT( INTEGER*4 target,
LOGICAL*1 reset,
INTEGER*4 format,
INTEGER*4 type,
CHARACTER*8 values )
PARAMETERS
target Must be GL_MINMAX_EXT.
reset If GL_TRUE, all entries in the minmax table that are actually
returned are reset to their initial values. (Other entries are
unaltered.) If GL_FALSE, the minmax table is unaltered.
format The format of the data to be returned in values. Must be one of
GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA, GL_RGB, GL_RGBA,
GL_ABGR_EXT, GL_LUMINANCE, or GL_LUMINANCE_ALPHA.
type The type of the data to be returned in values. Must be one of
GL_UNSIGNED_BYTE, GL_BYTE, GL_UNSIGNED_SHORT, GL_SHORT,
GL_UNSIGNED_INT, GL_INT, GL_FLOAT, GL_UNSIGNED_BYTE_3_3_2_EXT,
GL_UNSIGNED_SHORT_4_4_4_4_EXT, GL_UNSIGNED_SHORT_5_5_5_1_EXT,
GL_UNSIGNED_INT_8_8_8_8_EXT, or GL_UNSIGNED_INT_10_10_10_2_EXT.
values A pointer to storage for the returned values.
DESCRIPTION
fglGetMinmaxEXT returns the accumulated minimum and maximum pixel values
(computed on a per-component basis) in a one-dimensional image of width
2. The first set of return values are the minima, and the second set of
return values are the maxima. The format of the return values is
determined by format, and their type is determined by type.
No pixel transfer operations are performed on the return values, but
pixel storage modes that are applicable to 1-dimensional images are
performed. Color components that are requested in the specified format,
but which are not included in the internal format of the minmax table,
are returned as zero. The assignment of internal color components to the
components requested by format are as follows:
Internal Component Result Component
_____________________________________
red red
green green
blue blue
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fglGetMinmaxEXT(3G) OpenGL Reference fglGetMinmaxEXT(3G)
alpha alpha
luminance red
If reset is GL_TRUE, the minmax table entries corresponding to the return
values are reset to their initial values. Minimum and maximum values
that are not returned are not modified, even if reset is GL_TRUE.
ERRORS
GL_INVALID_ENUM is generated if target is not GL_MINMAX_EXT.
GL_INVALID_ENUM is generated if format is not one of the allowable
values.
GL_INVALID_ENUM is generated if type is not one of the allowable values.
GL_INVALID_OPERATION is generated if fglGetMinmaxEXT is executed between
the execution of fglBegin and the corresponding execution of fglEnd.
If type is set to GL_UNSIGNED_BYTE_3_3_2_EXT,
GL_UNSIGNED_SHORT_4_4_4_4_EXT, GL_UNSIGNED_SHORT_5_5_5_1_EXT,
GL_UNSIGNED_INT_8_8_8_8_EXT, or GL_UNSIGNED_INT_10_10_10_2_EXT and the
EXT_packed_pixels extension is not supported then a GL_INVALID_ENUM error
is generated.
MACHINE DEPENDENCIES
On RealityEngine, RealityEngine2, and VTX systems, histogram and minmax
may not be used when rendering to pixmaps.
SEE ALSO
fglMinmaxEXT, fglResetMinmaxEXT, fglGetMinmaxParameterEXT.
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