glGetMinmaxEXT(3G) OpenGL Reference glGetMinmaxEXT(3G)
NAME
glGetMinmaxEXT - get minimum and maximum pixel values
C SPECIFICATION
void glGetMinmaxEXT( GLenum target,
GLboolean reset,
GLenum format,
GLenum type,
GLvoid *values )
PARAMETERS
target Must be GLMINMAXEXT.
reset If GLTRUE, all entries in the minmax table that are actually
returned are reset to their initial values. (Other entries are
unaltered.) If GLFALSE, the minmax table is unaltered.
format The format of the data to be returned in values. Must be one of
GLRED, GLGREEN, GLBLUE, GLALPHA, GLRGB, GLRGBA,
GLABGREXT, GLLUMINANCE, or GLLUMINANCEALPHA.
type The type of the data to be returned in values. Must be one of
GLUNSIGNEDBYTE, GLBYTE, GLUNSIGNEDSHORT, GLSHORT,
GLUNSIGNEDINT, GLINT, GLFLOAT, GLUNSIGNEDBYTE332EXT,
GLUNSIGNEDSHORT4444EXT, GLUNSIGNEDSHORT5551EXT,
GLUNSIGNEDINT8888EXT, or GLUNSIGNEDINT1010102EXT.
values A pointer to storage for the returned values.
DESCRIPTION
glGetMinmaxEXT 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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glGetMinmaxEXT(3G) OpenGL Reference glGetMinmaxEXT(3G)
alpha alpha
luminance red
If reset is GLTRUE, 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 GLTRUE.
ERRORS
GLINVALIDENUM is generated if target is not GLMINMAXEXT.
GLINVALIDENUM is generated if format is not one of the allowable
values.
GLINVALIDENUM is generated if type is not one of the allowable values.
GLINVALIDOPERATION is generated if glGetMinmaxEXT is executed between
the execution of glBegin and the corresponding execution of glEnd.
If type is set to GLUNSIGNEDBYTE332EXT,
GLUNSIGNEDSHORT4444EXT, GLUNSIGNEDSHORT5551EXT,
GLUNSIGNEDINT8888EXT, or GLUNSIGNEDINT1010102EXT and the
EXTpackedpixels extension is not supported then a GLINVALIDENUM error
is generated.
SEE ALSO
glMinmaxEXT, glResetMinmaxEXT, glGetMinmaxParameterEXT.
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