glGetHistogramParameter — get histogram parameters
void glGetHistogramParameterfv( | GLenum | target, |
GLenum | pname, | |
GLfloat * | params) ; |
void glGetHistogramParameteriv( | GLenum | target, |
GLenum | pname, | |
GLint * | params) ; |
target
Must be one of
GL_HISTOGRAM
or
GL_PROXY_HISTOGRAM
.
pname
The name of the parameter to be retrieved.
Must be one of
GL_HISTOGRAM_WIDTH
,
GL_HISTOGRAM_FORMAT
,
GL_HISTOGRAM_RED_SIZE
,
GL_HISTOGRAM_GREEN_SIZE
,
GL_HISTOGRAM_BLUE_SIZE
,
GL_HISTOGRAM_ALPHA_SIZE
,
GL_HISTOGRAM_LUMINANCE_SIZE
, or
GL_HISTOGRAM_SINK
.
params
Pointer to storage for the returned values.
glGetHistogramParameter
is used to query parameter values for the current histogram or for
a proxy. The histogram state information may be queried by calling
glGetHistogramParameter
with a target
of GL_HISTOGRAM
(to
obtain information for the current histogram table) or
GL_PROXY_HISTOGRAM
(to obtain information from the most recent
proxy request) and one of the following values for the pname
argument:
Parameter | Description |
---|---|
GL_HISTOGRAM_WIDTH
| Histogram table width |
GL_HISTOGRAM_FORMAT
| Internal format |
GL_HISTOGRAM_RED_SIZE
| Red component counter size, in bits |
GL_HISTOGRAM_GREEN_SIZE
| Green component counter size, in bits |
GL_HISTOGRAM_BLUE_SIZE
| Blue component counter size, in bits |
GL_HISTOGRAM_ALPHA_SIZE
| Alpha component counter size, in bits |
GL_HISTOGRAM_LUMINANCE_SIZE
| Luminance component counter size, in bits |
GL_HISTOGRAM_SINK
| Value of the sink parameter |
glGetHistogramParameter
is present only if 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 pname
is not one of the allowable
values.
GL_INVALID_OPERATION
is generated if glGetHistogramParameter
is executed
between the execution of glBegin and the corresponding
execution of glEnd.
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