glGetHistogramParameter.3G man page

glGetHistogramParameter — 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 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

Notes

glGetHistogramParameter is present only if 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().

See Also

glGetHistogram(), glHistogram()

Authors

opengl.org

Info

02/10/2017 opengl.org OpenGL Manual