GLGETHISTOGRAM(3G) UNIX Programmer's Manual GLGETHISTOGRAM(3G)
glGetHistogram - get histogram table
void glGetHistogram( GLenum target,
GLboolean reset,
GLenum format,
GLenum type,
GLvoid *values )
target Must be GL_HISTOGRAM.
reset If GL_TRUE, each component counter that is actually
returned is reset to zero. (Other counters are
unaffected.) If GL_FALSE, none of the counters in
the histogram table is modified.
format The of values to be returned in values. Must be one
of GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA, GL_RGB,
GL_BGR, GL_RGBA, GL_BGRA, GL_LUMINANCE, or
GL_LUMINANCE_ALPHA.
type The type of values to be returned in values. Sym-
bolic constants GL_UNSIGNED_BYTE, GL_BYTE,
GL_BITMAP, GL_UNSIGNED_SHORT, GL_SHORT,
GL_UNSIGNED_INT, GL_INT, GL_FLOAT,
GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV,
GL_UNSIGNED_SHORT_5_6_5,
GL_UNSIGNED_SHORT_5_6_5_REV,
GL_UNSIGNED_SHORT_4_4_4_4,
GL_UNSIGNED_SHORT_4_4_4_4_REV,
GL_UNSIGNED_SHORT_5_5_5_1,
GL_UNSIGNED_SHORT_1_5_5_5_REV,
GL_UNSIGNED_INT_8_8_8_8,
GL_UNSIGNED_INT_8_8_8_8_REV,
GL_UNSIGNED_INT_10_10_10_2, and
GL_UNSIGNED_INT_2_10_10_10_REV are accepted.
values A pointer to storage for the returned histogram
table.
glGetHistogram returns the current histogram table as a
one-dimensional image with the same width as the histogram.
No pixel transfer operations are performed on this image,
but pixel storage modes that are applicable to 1D images are
honored.
MirOS BSD #10-current Printed 20.2.2012 1
GLGETHISTOGRAM(3G) UNIX Programmer's Manual GLGETHISTOGRAM(3G)
Color components that are requested in the specified format,
but which are not included in the internal of the histo-
gram, are returned as zero.
MirOS BSD #10-current Printed 20.2.2012 2
GLGETHISTOGRAM(3G) UNIX Programmer's Manual GLGETHISTOGRAM(3G)
The assignments of internal color components to the com-
ponents requested by format are:
________________________________________
Internal Component Resulting Component
________________________________________
Red Red
Green Green
Blue Blue
Alpha Alpha
Luminance Red
________________________________________
glGetHistogram 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 GL_HISTOGRAM.
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 glGetHistogram is exe-
cuted between the execution of glBegin and the corresponding
execution of glEnd.
GL_INVALID_OPERATION is generated if type is one of
GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV,
GL_UNSIGNED_SHORT_5_6_5, or GL_UNSIGNED_SHORT_5_6_5_REV and
format is not GL_RGB.
GL_INVALID_OPERATION is generated if type is one of
GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV,
GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV,
GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV,
GL_UNSIGNED_INT_10_10_10_2, or
GL_UNSIGNED_INT_2_10_10_10_REV and format is neither GL_RGBA
nor GL_BGRA.
glHistogram(3G), glResetHistogram(3G),
glGetHistogramParameter(3G)
MirOS BSD #10-current Printed 20.2.2012 3
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