dll/opengl/mesa/src/glu/sgi/libnurbs/internals/trimline.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  * 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