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 = ⊤ 81 upper.index = top.ustart; 82 } else 83 upper.line = 0; 84 85 if( bot.ustart <= bot.uend ) { 86 lower.line = ⊥ 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 } 165 166