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_C_ License Applicability. Except to the extent portions of this file are
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_C_ made subject to an alternative license as permitted in the SGI Free
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_C_ Software License B, Version 1.1 (the "License"), the contents of this
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_C_ file are subject only to the provisions of the License. You may not use
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_C_ this file except in compliance with the License. You may obtain a copy
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_C_ of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
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_C_ Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
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_C_ http://oss.sgi.com/projects/FreeB
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_C_ Note that, as provided in the License, the Software is distributed on an
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_C_ "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
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_C_ DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
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_C_ CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
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_C_ PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
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_C_ Original Code. The Original Code is: OpenGL Sample Implementation,
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_C_ Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
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_C_ Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
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_C_ Copyright in any portions created by third parties is as indicated
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_C_ elsewhere herein. All Rights Reserved.
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_C_ Additional Notice Provisions: The application programming interfaces
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_C_ established by SGI in conjunction with the Original Code are The
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_C_ OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
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_C_ April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
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_C_ 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
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_C_ Window System(R) (Version 1.3), released October 19, 1998. This software
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_C_ was created using the OpenGL(R) version 1.2.1 Sample Implementation
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_C_ published by SGI, but has not been independently verified as being
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_C_ compliant with the OpenGL(R) version 1.2.1 Specification.
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_C_ The first character in this file must be an '_'!
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_C_ Anything on a line after _C_ is ignored
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_define(_filters,eqn)_C_
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_C_ eqn is automatically replaced with neqn for nroff
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_header(PointSize,specify the diameter of rasterized points)
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Specifies the diameter of rasterized points.
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The initial value is 1.
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_cmnd specifies the rasterized diameter of both aliased and antialiased
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Using a point size other than 1 has different effects,
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depending on whether point antialiasing is enabled.
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To enable and disable point antialiasing, call
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_cmnd(Enable) and _cmnd(Disable)
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with argument _const(POINT_SMOOTH). Point antialiasing is initially disabled.
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If point antialiasing is disabled,
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the actual size is determined by rounding the supplied size
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to the nearest integer.
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(If the rounding results in the value 0,
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it is as if the point size were 1.)
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If the rounded size is odd,
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of the pixel fragment that represents the point is computed as
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( $ \(lf ~ x sub w ~ \(rf ~+~ .5 $, $ \(lf ~ y sub w ~ \(rf ~+~ .5 $)
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where $w$ subscripts indicate window coordinates.
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All pixels that lie within the square grid of the rounded size centered at
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( $ \(lf ~ x sub w ~+~ .5 ~ \(rf$, $ \(lf ~ y sub w ~+~ .5 ~ \(rf $)
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and the rasterized fragment's centers are the half-integer window coordinates
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within the square of the rounded size centered at
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All pixel fragments produced in rasterizing a nonantialiased point are
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assigned the same associated data,
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that of the vertex corresponding to the point.
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If antialiasing is enabled,
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then point rasterization produces a fragment for each pixel square
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that intersects the region lying within the circle having diameter
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equal to the current point size and centered at the point's
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($ x sub w $, $ y sub w $).
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The coverage value for each fragment is the window coordinate area
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of the intersection of the circular region with the corresponding pixel square.
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This value is saved and used in the final rasterization step.
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The data associated with each fragment is the data associated with
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the point being rasterized.
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Not all sizes are supported when point antialiasing is enabled.
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If an unsupported size is requested,
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the nearest supported size is used.
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Only size 1 is guaranteed to be supported;
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others depend on the implementation.
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To query the range of supported sizes and the size difference between
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supported sizes within the range, call
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_cmnd(Get) with arguments
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_const(SMOOTH_POINT_SIZE_RANGE) and
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_const(SMOOTH_POINT_SIZE_GRANULARITY).
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For aliased points, query the supported ranges and granularity with
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_cmnd(Get) with arguments
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_const(ALIASED_POINT_SIZE_RANGE) and
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_const(ALIASED_POINT_SIZE_GRANULARITY).
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The point size specified by _cmnd is always returned when _const(POINT_SIZE)
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Clamping and rounding for aliased and antialiased points have no effect
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on the specified value.
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A non-antialiased point size may be clamped to an implementation-dependent
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Although this maximum cannot be queried,
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it must be no less than the maximum value for antialiased points,
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rounded to the nearest integer value.
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_const(POINT_SIZE_RANGE) and _const(POINT_SIZE_GRANULARITY) are
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deprecated in GL versions 1.2 and greater. Their functionality has been
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replaced by _const(SMOOTH_POINT_SIZE_RANGE) and
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_const(SMOOTH_POINT_SIZE_GRANULARITY).
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_const(INVALID_VALUE) is generated if _param1 is less than or equal to 0.
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_const(INVALID_OPERATION) is generated if _cmnd
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is executed between the execution of _cmnd(Begin)
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and the corresponding execution of _cmnd(End).
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_cmnd(Get) with argument _const(POINT_SIZE)
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_cmnd(Get) with argument _const(ALIASED_POINT_SIZE_RANGE)
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_cmnd(Get) with argument _const(ALIASED_POINT_SIZE_GRANULARITY)
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_cmnd(Get) with argument _const(SMOOTH_POINT_SIZE_RANGE)
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_cmnd(Get) with argument _const(SMOOTH_POINT_SIZE_GRANULARITY)
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_cmnd(IsEnabled) with argument _const(POINT_SMOOTH)