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Diffstat (limited to 'nx-X11/extras/ogl-sample/main/doc/man/mangl/standard/selectbuffer.gl')
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diff --git a/nx-X11/extras/ogl-sample/main/doc/man/mangl/standard/selectbuffer.gl b/nx-X11/extras/ogl-sample/main/doc/man/mangl/standard/selectbuffer.gl new file mode 100644 index 000000000..c1772410c --- /dev/null +++ b/nx-X11/extras/ogl-sample/main/doc/man/mangl/standard/selectbuffer.gl @@ -0,0 +1,127 @@ +_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,eqn)_C_ +_C_ eqn is automatically replaced with neqn for nroff +_header(SelectBuffer,establish a buffer for selection mode values) +_names(SelectBuffer) +.SH PARAMETERS +_phead(_param1) +Specifies the size of _param2. +_phead(_param2) +Returns the selection data. +.SH DESCRIPTION +_cmnd has two arguments: +_param2 is a pointer to an array of unsigned integers, +and _param1 indicates the size of the array. +_param2 returns values from the name stack +(see _cmnd(InitNames), _cmnd(LoadName), _cmnd(PushName)) +when the rendering mode is _const(SELECT) (see _cmnd(RenderMode)). +_cmnd must be issued before selection mode is enabled, +and it must not be issued while the rendering mode is _const(SELECT). +.P +A programmer can use selection to determine which primitives +are drawn into some region of a window. +The region is defined by the current modelview and perspective matrices. +.P +In selection mode, no pixel fragments are produced from rasterization. +Instead, +if a primitive or a raster position intersects the clipping +volume defined by the viewing frustum +and the user-defined clipping planes, +this primitive causes a selection hit. +(With polygons, no hit occurs if the polygon is culled.) +When a change is made to the name stack, +or when _cmnd(RenderMode) is called, +a hit record is copied to _param2 if any hits have occurred since the +last such event +(name stack change or +_cmnd(RenderMode) call). +The hit record consists of the number of names in the name stack at the +time of the event, followed by the minimum and maximum depth values +of all vertices that hit since the previous event, +followed by the name stack contents, +bottom name first. +.P +Depth values (which are in the range [0,1]) are multiplied by 2^32 - 1, +before being placed in the hit record. +.P +An internal index into _param2 is reset to 0 whenever selection mode +is entered. +Each time a hit record is copied into _param2, +the index is incremented to point to the cell just past the end +of the block of names \- that is, to the next available cell. +If the hit record is larger than the number of remaining locations in _param2, +as much data as can fit is copied, +and the overflow flag is set. +If the name stack is empty when a hit record is copied, +that record consists of 0 followed by the minimum and maximum depth values. +.P +To exit selection mode, call _cmnd(RenderMode) with an argument +other than _const(SELECT). +Whenever _cmnd(RenderMode) is called while the render mode is _const(SELECT), +it returns the number of hit records copied to _param2, +resets the overflow flag and the selection buffer pointer, +and initializes the name stack to be empty. +If the overflow bit was set when _cmnd(RenderMode) was called, +a negative hit record count is returned. +.SH NOTES +The contents of _param2 is undefined until _cmnd(RenderMode) is called +with an argument other than _const(SELECT). +.P +_cmnd(Begin)/_cmnd(End) primitives and calls to _cmnd(RasterPos) +can result in hits. +.SH ERRORS +_const(INVALID_VALUE) is generated if _param1 is negative. +.P +_const(INVALID_OPERATION) is generated if _cmnd is called while the +render mode is _const(SELECT), +or if _cmnd(RenderMode) is called with argument _const(SELECT) before +_cmnd is called at least once. +.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(Get) with argument _const(NAME_STACK_DEPTH) +.br +_cmnd(Get) with argument _const(SELECTION_BUFFER_SIZE) +.br +_cmnd(GetPointerv) with argument _const(SELECTION_BUFFER_POINTER) +.SH SEE ALSO +_cmnd(FeedbackBuffer), +_cmnd(InitNames), +_cmnd(LoadName), +_cmnd(PushName), +_cmnd(RenderMode) |