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 * trimline.c++ 37 * 38 */ 39 40 //#include "glimports.h" 41 //#include "myassert.h" 42 //#include "mystdio.h" 43 #include "trimline.h" 44 #include "backend.h" 45 46 Trimline::Trimline() 47 { 48 size = 0; pts = 0; numverts = 0; 49 tinterp = &t; binterp = &b; 50 } 51 52 Trimline::~Trimline() 53 { 54 if( pts ) delete[] pts; 55 } 56 57 void 58 Trimline::init( TrimVertex *v ) 59 { 60 reset(); 61 grow(1); 62 append(v); 63 } 64 65 inline void 66 Trimline::grow( long npts ) 67 { 68 if( size < npts ) { 69 size = 2 * npts; 70 if( pts ) delete[] pts; 71 pts = new TrimVertex_p[size]; 72 } 73 } 74 75 inline void 76 Trimline::append( TrimVertex *v ) 77 { 78 assert( numverts != size ); 79 pts[numverts++] = v; 80 } 81 82 void 83 Trimline::init( long npts, Arc_ptr jarc, long last ) 84 { 85 jarcl.init( jarc, 0, last ); 86 grow( npts + 2 ); 87 } 88 89 inline void 90 Trimline::swap() 91 { 92 TrimVertex *tmp=tinterp; 93 tinterp=binterp; 94 binterp=tmp; 95 } 96 97 void 98 Trimline::getNextPt() 99 { 100 *binterp = *jarcl.getnextpt(); 101 } 102 103 void 104 Trimline::getPrevPt() 105 { 106 *binterp = *jarcl.getprevpt(); 107 } 108 109 /*---------------------------------------------------------------------- 110 * getNextPts - make arrays of pointers to trim points on left and right 111 * hulls of trim strip. 112 *---------------------------------------------------------------------- 113 */ 114 void 115 Trimline::getNextPts( REAL vval, Backend& backend ) 116 { 117 reset(); swap(); append( tinterp ); 118 assert( tinterp->param[1] >= vval ); 119 120 register TrimVertex *p; 121 for( p=jarcl.getnextpt() ; p->param[1] >= vval; p=jarcl.getnextpt() ) { 122 append( p ); 123 } 124 125 /* compute and copy pointer to final point on left hull */ 126 if( interpvert( last(), p, binterp, vval ) ) { 127 binterp->nuid = p->nuid; 128 backend.triangle( p, binterp, last() ); 129 append( binterp ); 130 } 131 jarcl.reverse(); 132 (void) jarcl.getprevpt(); /* reset jarcl to proper position */ 133 jarcl.reverse(); 134 } 135 136 void 137 Trimline::getPrevPts( REAL vval, Backend& backend ) 138 { 139 reset(); swap(); append( tinterp ); 140 assert( tinterp->param[1] >= vval ); 141 142 register TrimVertex *q; 143 for( q=jarcl.getprevpt(); q->param[1] >= vval; q=jarcl.getprevpt() ) { 144 append( q ); 145 } 146 147 /* compute and copy pointer to final point on right hull */ 148 if( interpvert( q, last(), binterp, vval ) ) { 149 binterp->nuid = q->nuid; 150 backend.triangle( last(), binterp, q ); 151 append( binterp ); 152 } 153 jarcl.reverse(); 154 (void) jarcl.getnextpt(); /* reset jarcl to proper position */ 155 jarcl.reverse(); 156 } 157 158 void 159 Trimline::getNextPts( Arc_ptr botarc ) 160 { 161 reset(); swap(); append( tinterp ); 162 163 #ifndef NDEBUG 164 PwlArc *lastpwl = botarc->prev->pwlArc; 165 TrimVertex *lastpt1 = &lastpwl->pts[lastpwl->npts-1]; 166 #endif 167 TrimVertex *lastpt2 = botarc->pwlArc->pts; 168 register TrimVertex *p = jarcl.getnextpt(); 169 for( append( p ); p != lastpt2; append( p ) ) { 170 assert( p != lastpt1 ); 171 p = jarcl.getnextpt(); 172 } 173 } 174 175 void 176 Trimline::getPrevPts( Arc_ptr botarc ) 177 { 178 reset(); swap(); append( tinterp ); 179 180 PwlArc *lastpwl = botarc->prev->pwlArc; 181 TrimVertex *lastpt1 = &lastpwl->pts[lastpwl->npts-1]; 182 #ifndef NDEBUG 183 TrimVertex *lastpt2 = botarc->pwlArc->pts; 184 #endif 185 186 register TrimVertex *q = jarcl.getprevpt(); 187 for( append( q ); q != lastpt1; append( q ) ) { 188 assert( q != lastpt2 ); 189 q = jarcl.getprevpt(); 190 } 191 } 192 193 194 long 195 Trimline::interpvert( TrimVertex *a, TrimVertex *b, TrimVertex *c, REAL vval ) 196 { 197 REAL denom = a->param[1] - b->param[1]; 198 199 if(denom != 0) { 200 if( vval == a->param[1] ) { 201 c->param[0] = a->param[0]; 202 c->param[1] = a->param[1]; 203 c->nuid = a->nuid; 204 return 0; 205 } else if( vval == b->param[1] ) { 206 c->param[0] = b->param[0]; 207 c->param[1] = b->param[1]; 208 c->nuid = b->nuid; 209 return 0; 210 } else { 211 REAL r = (a->param[1] - vval)/denom; 212 c->param[0] = a->param[0] - r * (a->param[0] - b->param[0]); 213 c->param[1] = vval; 214 return 1; 215 } 216 } else { 217 c->param[0] = a->param[0]; 218 c->param[1] = a->param[1]; 219 c->nuid = a->nuid; 220 return 0; 221 } 222 } 223 224