dll/opengl/glu32/src/libnurbs/internals/hull.cc

   1 /*
   2 ** License Applicability. Except to the extent portions of this file are
   3 ** made subject to an alternative license as permitted in the SGI Free
   4 ** Software License B, Version 1.1 (the "License"), the contents of this
   5 ** file are subject only to the provisions of the License. You may not use
   6 ** this file except in compliance with the License. You may obtain a copy
   7 ** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
   8 ** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
   9 **
  10 ** http://oss.sgi.com/projects/FreeB
  11 **
  12 ** Note that, as provided in the License, the Software is distributed on an
  13 ** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
  14 ** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
  15 ** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
  16 ** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
  17 **
  18 ** Original Code. The Original Code is: OpenGL Sample Implementation,
  19 ** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
  20 ** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
  21 ** Copyright in any portions created by third parties is as indicated
  22 ** elsewhere herein. All Rights Reserved.
  23 **
  24 ** Additional Notice Provisions: The application programming interfaces
  25 ** established by SGI in conjunction with the Original Code are The
  26 ** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
  27 ** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
  28 ** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
  29 ** Window System(R) (Version 1.3), released October 19, 1998. This software
  30 ** was created using the OpenGL(R) version 1.2.1 Sample Implementation
  31 ** published by SGI, but has not been independently verified as being
  32 ** compliant with the OpenGL(R) version 1.2.1 Specification.
  33 */
  34
  35 /*
  36  * hull.c++
  37  *
  38  */
  39
  40 //#include "glimports.h"
  41 //#include "myassert.h"
  42 //#include "mystdio.h"
  43 #include "hull.h"
  44 //#include "gridvertex.h"
  45 //#include "gridtrimvertex.h"
  46 //#include "gridline.h"
  47 //#include "trimline.h"
  48 //#include "uarray.h"
  49 //#include "trimregion.h"
  50
  51 Hull::Hull( void )
  52 {}
  53
  54 Hull::~Hull( void )
  55 {}
  56
  57 /*----------------------------------------------------------------------
  58  * Hull:init - this routine does the initialization needed before any
  59  *              calls to nextupper or nextlower can be made.
  60  *----------------------------------------------------------------------
  61  */
  62 void
  63 Hull::init( void )
  64 {
  65     TrimVertex *lfirst = left.first();
  66     TrimVertex *llast = left.last();
  67     if( lfirst->param[0] <= llast->param[0] ) {
  68         fakeleft.init( left.first() );
  69         upper.left = &fakeleft;
  70         lower.left = &left;
  71     } else {
  72         fakeleft.init( left.last() );
  73         lower.left = &fakeleft;
  74         upper.left = &left;
  75     }
  76     upper.left->last();
  77     lower.left->first();
  78
  79     if( top.ustart <= top.uend ) {
  80         upper.line = &top;
  81         upper.index = top.ustart;
  82     } else
  83         upper.line = 0;
  84
  85     if( bot.ustart <= bot.uend ) {
  86         lower.line = &bot;
  87         lower.index = bot.ustart;
  88     } else
  89         lower.line = 0;
  90
  91     TrimVertex *rfirst = right.first();
  92     TrimVertex *rlast = right.last();
  93     if( rfirst->param[0] <= rlast->param[0] ) {
  94         fakeright.init( right.last() );
  95         lower.right = &fakeright;
  96         upper.right = &right;
  97     } else {
  98         fakeright.init( right.first() );
  99         upper.right = &fakeright;
 100         lower.right = &right;
 101     }
 102     upper.right->first();
 103     lower.right->last();
 104 }
 105
 106 /*----------------------------------------------------------------------
 107  * nextupper - find next vertex on upper hull of trim region.
 108  *               - if vertex is on trim curve, set vtop point to
 109  *                 that vertex.  if vertex is on grid, set vtop to
 110  *                 point to temporary area and stuff coordinants into
 111  *                 temporary vertex.  Also, place grid coords in temporary
 112  *                 grid vertex.
 113  *----------------------------------------------------------------------
 114  */
 115 GridTrimVertex *
 116 Hull::nextupper( GridTrimVertex *gv )
 117 {
 118     if( upper.left ) {
 119         gv->set( upper.left->prev() );
 120         if( gv->isTrimVert() ) return gv;
 121         upper.left = 0;
 122     }
 123
 124     if( upper.line ) {
 125         assert( upper.index <= upper.line->uend );
 126         gv->set( uarray.uarray[upper.index], upper.line->vval );
 127         gv->set( upper.index, upper.line->vindex );
 128         if( upper.index++ == upper.line->uend ) upper.line = 0;
 129         return gv;
 130     }
 131
 132     if( upper.right ) {
 133         gv->set( upper.right->next() );
 134         if( gv->isTrimVert() ) return gv;
 135         upper.right = 0;
 136     }
 137
 138     return 0;
 139 }
 140
 141 GridTrimVertex *
 142 Hull::nextlower( GridTrimVertex *gv )
 143 {
 144     if( lower.left ) {
 145         gv->set( lower.left->next() );
 146         if( gv->isTrimVert() ) return gv;
 147         lower.left = 0;
 148     }
 149
 150     if( lower.line ) {
 151         gv->set( uarray.uarray[lower.index], lower.line->vval );
 152         gv->set( lower.index, lower.line->vindex );
 153         if( lower.index++ == lower.line->uend ) lower.line = 0;
 154         return gv;
 155     }
 156
 157     if( lower.right ) {
 158         gv->set( lower.right->prev() );
 159         if( gv->isTrimVert() ) return gv;
 160         lower.right = 0;
 161     }
 162
 163     return 0;
 164 }
 165