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glGetHistogramParameterfv, glGetHistogramParameteriv - 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
|
| GL_HISTOGRAM_RED_SIZE Red component counter size, in bits |
| GL_HISTOGRAM_GREEN_SIZE Green
component counter size, in bits |
| Parameter Description |
| 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 GL_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.
glGetHistogram(3G)
, glHistogram(3G)
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