GLMINMAX(3G) OpenGL Manual GLMINMAX(3G)
NAME
glMinmax - define minmax table
C SPECIFICATION
void glMinmax(GLenum target, GLenum internalformat, GLboolean sink);
PARAMETERS
target
The minmax table whose parameters are to be set. Must be GL_MINMAX.
internalformat
The format of entries in the minmax table. Must be one of GL_ALPHA, GL_ALPHA4, GL_ALPHA8, GL_ALPHA12, GL_ALPHA16, GL_LUMINANCE,
GL_LUMINANCE4, GL_LUMINANCE8, GL_LUMINANCE12, GL_LUMINANCE16, GL_LUMINANCE_ALPHA, GL_LUMINANCE4_ALPHA4, GL_LUMINANCE6_ALPHA2,
GL_LUMINANCE8_ALPHA8, GL_LUMINANCE12_ALPHA4, GL_LUMINANCE12_ALPHA12, GL_LUMINANCE16_ALPHA16, GL_R3_G3_B2, GL_RGB, GL_RGB4, GL_RGB5,
GL_RGB8, GL_RGB10, GL_RGB12, GL_RGB16, GL_RGBA, GL_RGBA2, GL_RGBA4, GL_RGB5_A1, GL_RGBA8, GL_RGB10_A2, GL_RGBA12, or GL_RGBA16.
sink
If GL_TRUE, pixels will be consumed by the minmax process and no drawing or texture loading will take place. If GL_FALSE, pixels will
proceed to the final conversion process after minmax.
DESCRIPTION
When GL_MINMAX is enabled, the RGBA components of incoming pixels are compared to the minimum and maximum values for each component, which
are stored in the two-element minmax table. (The first element stores the minima, and the second element stores the maxima.) If a pixel
component is greater than the corresponding component in the maximum element, then the maximum element is updated with the pixel component
value. If a pixel component is less than the corresponding component in the minimum element, then the minimum element is updated with the
pixel component value. (In both cases, if the internal format of the minmax table includes luminance, then the R color component of
incoming pixels is used for comparison.) The contents of the minmax table may be retrieved at a later time by calling glGetMinmax(). The
minmax operation is enabled or disabled by calling glEnable() or glDisable(), respectively, with an argument of GL_MINMAX.
glMinmax redefines the current minmax table to have entries of the format specified by internalformat. The maximum element is initialized
with the smallest possible component values, and the minimum element is initialized with the largest possible component values. The values
in the previous minmax table, if any, are lost. If sink is GL_TRUE, then pixels are discarded after minmax; no further processing of the
pixels takes place, and no drawing, texture loading, or pixel readback will result.
NOTES
glMinmax 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 internalformat is not one of the allowable values.
GL_INVALID_OPERATION is generated if glMinmax is executed between the execution of glBegin() and the corresponding execution of glEnd().
ASSOCIATED GETS
glGetMinmaxParameter()
SEE ALSO
glGetMinmax(), glResetMinmax()
COPYRIGHT
Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.
AUTHORS
opengl.org
opengl.org 06/10/2014 GLMINMAX(3G)
