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_C_ License Applicability. Except to the extent portions of this file are
_C_ made subject to an alternative license as permitted in the SGI Free
_C_ Software License B, Version 1.1 (the "License"), the contents of this
_C_ file are subject only to the provisions of the License. You may not use
_C_ this file except in compliance with the License. You may obtain a copy
_C_ of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
_C_ Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
_C_
_C_ http://oss.sgi.com/projects/FreeB
_C_
_C_ Note that, as provided in the License, the Software is distributed on an
_C_ "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
_C_ DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
_C_ CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
_C_ PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
_C_
_C_ Original Code. The Original Code is: OpenGL Sample Implementation,
_C_ Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
_C_ Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
_C_ Copyright in any portions created by third parties is as indicated
_C_ elsewhere herein. All Rights Reserved.
_C_
_C_ Additional Notice Provisions: The application programming interfaces
_C_ established by SGI in conjunction with the Original Code are The
_C_ OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
_C_ April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
_C_ 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
_C_ Window System(R) (Version 1.3), released October 19, 1998. This software
_C_ was created using the OpenGL(R) version 1.2.1 Sample Implementation
_C_ published by SGI, but has not been independently verified as being
_C_ compliant with the OpenGL(R) version 1.2.1 Specification.
_C_
_C_ The first character in this file must be an '_'!
_C_ Anything on a line after _C_ is ignored
_define(_filters,tbl | eqn)_C_
_C_ eqn is automatically replaced with neqn for nroff
_header(CopyColorTable,copy pixels into a color table)
_names(CopyColorTable)
.EQ
delim $$
.EN
.SH PARAMETERS
_define(@<__target>@,@<_param1>@)_C_
_define(@<__internalformat>@,@<_param2>@)_C_
_define(@<__x>@,@<_param3>@)_C_
_define(@<__y>@,@<_param4>@)_C_
_define(@<__width>@,@<_param5>@)_C_
_phead(__target)
The color table target. Must be
_const(COLOR_TABLE),
_const(POST_CONVOLUTION_COLOR_TABLE),
or _const(POST_COLOR_MATRIX_COLOR_TABLE).
_phead(__internalformat)
The internal storage format of the texture image.
Must be one of the following symbolic constants:
_const(ALPHA),
_const(ALPHA4),
_const(ALPHA8),
_const(ALPHA12),
_const(ALPHA16),
_const(LUMINANCE),
_const(LUMINANCE4),
_const(LUMINANCE8),
_const(LUMINANCE12),
_const(LUMINANCE16),
_const(LUMINANCE_ALPHA),
_const(LUMINANCE4_ALPHA4),
_const(LUMINANCE6_ALPHA2),
_const(LUMINANCE8_ALPHA8),
_const(LUMINANCE12_ALPHA4),
_const(LUMINANCE12_ALPHA12),
_const(LUMINANCE16_ALPHA16),
_const(INTENSITY),
_const(INTENSITY4),
_const(INTENSITY8),
_const(INTENSITY12),
_const(INTENSITY16),
_const(R3_G3_B2),
_const(RGB),
_const(RGB4),
_const(RGB5),
_const(RGB8),
_const(RGB10),
_const(RGB12),
_const(RGB16),
_const(RGBA),
_const(RGBA2),
_const(RGBA4),
_const(RGB5_A1),
_const(RGBA8),
_const(RGB10_A2),
_const(RGBA12),
_const(RGBA16).
_phead(__x)
The x coordinate of the lower-left corner of the pixel rectangle
to be transferred to the color table.
_phead(__y)
The y coordinate of the lower-left corner of the pixel rectangle
to be transferred to the color table.
_phead(__width)
The width of the pixel rectangle.
.SH DESCRIPTION
_cmnd loads a color table with pixels from the current
_const(READ_BUFFER) (rather than from main memory, as is the case for
_cmnd(ColorTable)).
.P
The screen-aligned pixel rectangle with lower-left corner at (__x,\ __y)
having width __width and height 1
is loaded into the color table. If any pixels within
this region are outside the window that is associated with the GL
context, the values obtained for those pixels are undefined.
.P
The pixels in the rectangle are processed just as if
_cmnd(ReadPixels) were called, with __internalformat set to RGBA,
but processing stops after the final conversion to RGBA.
.P
The four scale parameters and the four bias parameters that are defined
for the table are then used to scale and bias the R, G, B, and A components
of each pixel. The scale and bias parameters are set by calling
_cmnd(ColorTableParameter).
.P
Next, the R, G, B, and A values are clamped to the range [0,1].
Each pixel is then converted to the internal format specified by
__internalformat. This conversion simply maps the component values of the pixel (R, G, B,
and A) to the values included in the internal format (red, green, blue,
alpha, luminance, and intensity). The mapping is as follows:
.P
.TS
center;
lb cb cb cb cb cb cb
l c c c c c c.
_
Internal Format Red Green Blue Alpha Luminance Intensity
_
_const(ALPHA) A
_const(LUMINANCE) R
_const(LUMINANCE_ALPHA) A R
_const(INTENSITY) R
_const(RGB) R G B
_const(RGBA) R G B A
_
.TE
.P
Finally, the red, green, blue, alpha, luminance, and/or intensity components of
the resulting pixels are stored in the color table.
They form a one-dimensional table with indices in the range
[0,\ __width\ \-\ 1].
.P
.SH NOTES
_cmnd is available only if _arbstring(imaging) is returned from calling
_cmnd(GetString) with an argument of _const(EXTENSIONS).
.SH ERRORS
_const(INVALID_ENUM) is generated when __target is not one of the
allowable values.
.P
_const(INVALID_VALUE) is generated if __width is less than zero.
.P
_const(INVALID_VALUE) is generated if __internalformat is not one of the
allowable values.
.P
_const(TABLE_TOO_LARGE) is generated if the requested color table
is too large to be supported by the implementation.
.P
_const(INVALID_OPERATION) is generated if _cmnd is executed
between the execution of _cmnd(Begin) and the corresponding
execution of _cmnd(End).
.SH ASSOCIATED GETS
_cmnd(GetColorTable),
_cmnd(GetColorTableParameter)
.SH SEE ALSO
_cmnd(ColorTable),
_cmnd(ColorTableParameter),
_cmnd(ReadPixels)
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