glGetHistogramParameterfv, glGetHistogramParameteriv
- get histogram parameters
C SPECIFICATION
void glGetHistogramParameterfv(
GLenum target,
GLenum pname,
GLfloat *params )
void glGetHistogramParameteriv(
GLenum target,
GLenum pname,
GLint *params )
PARAMETERS
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.
DESCRIPTION
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
NOTES
glGetHistogramParameter is present only if GL_ARB_imaging is returned when glGetString
is called with an argument of GL_EXTENSIONS.
ERRORS
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.
