1GLMINMAX(3G)                     OpenGL Manual                    GLMINMAX(3G)
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NAME

6       glMinmax - define minmax table
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C SPECIFICATION

9       void glMinmax(GLenum target, GLenum internalformat, GLboolean sink);
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PARAMETERS

12       target
13           The minmax table whose parameters are to be set. Must be GL_MINMAX.
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15       internalformat
16           The format of entries in the minmax table. Must be one of GL_ALPHA,
17           GL_ALPHA4, GL_ALPHA8, GL_ALPHA12, GL_ALPHA16, GL_LUMINANCE,
18           GL_LUMINANCE4, GL_LUMINANCE8, GL_LUMINANCE12, GL_LUMINANCE16,
19           GL_LUMINANCE_ALPHA, GL_LUMINANCE4_ALPHA4, GL_LUMINANCE6_ALPHA2,
20           GL_LUMINANCE8_ALPHA8, GL_LUMINANCE12_ALPHA4,
21           GL_LUMINANCE12_ALPHA12, GL_LUMINANCE16_ALPHA16, GL_R3_G3_B2,
22           GL_RGB, GL_RGB4, GL_RGB5, GL_RGB8, GL_RGB10, GL_RGB12, GL_RGB16,
23           GL_RGBA, GL_RGBA2, GL_RGBA4, GL_RGB5_A1, GL_RGBA8, GL_RGB10_A2,
24           GL_RGBA12, or GL_RGBA16.
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26       sink
27           If GL_TRUE, pixels will be consumed by the minmax process and no
28           drawing or texture loading will take place. If GL_FALSE, pixels
29           will proceed to the final conversion process after minmax.
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DESCRIPTION

32       When GL_MINMAX is enabled, the RGBA components of incoming pixels are
33       compared to the minimum and maximum values for each component, which
34       are stored in the two-element minmax table. (The first element stores
35       the minima, and the second element stores the maxima.) If a pixel
36       component is greater than the corresponding component in the maximum
37       element, then the maximum element is updated with the pixel component
38       value. If a pixel component is less than the corresponding component in
39       the minimum element, then the minimum element is updated with the pixel
40       component value. (In both cases, if the internal format of the minmax
41       table includes luminance, then the R color component of incoming pixels
42       is used for comparison.) The contents of the minmax table may be
43       retrieved at a later time by calling glGetMinmax(). The minmax
44       operation is enabled or disabled by calling glEnable() or glDisable(),
45       respectively, with an argument of GL_MINMAX.
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47       glMinmax redefines the current minmax table to have entries of the
48       format specified by internalformat. The maximum element is initialized
49       with the smallest possible component values, and the minimum element is
50       initialized with the largest possible component values. The values in
51       the previous minmax table, if any, are lost. If sink is GL_TRUE, then
52       pixels are discarded after minmax; no further processing of the pixels
53       takes place, and no drawing, texture loading, or pixel readback will
54       result.
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NOTES

57       glMinmax is present only if ARB_imaging is returned when glGetString()
58       is called with an argument of GL_EXTENSIONS.
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ERRORS

61       GL_INVALID_ENUM is generated if target is not one of the allowable
62       values.
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64       GL_INVALID_ENUM is generated if internalformat is not one of the
65       allowable values.
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67       GL_INVALID_OPERATION is generated if glMinmax is executed between the
68       execution of glBegin() and the corresponding execution of glEnd().
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ASSOCIATED GETS

71       glGetMinmaxParameter()
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SEE ALSO

74       glGetMinmax(), glResetMinmax()
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77       Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed
78       under the SGI Free Software B License. For details, see
79       http://oss.sgi.com/projects/FreeB/.
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AUTHORS

82       opengl.org
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86opengl.org                        06/10/2014                      GLMINMAX(3G)
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