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  * $Date: 2005/10/28 13:09:23 $ $Revision: 1.2 $
  39  * $Header: /home/krh/git/sync/mesa-cvs-repo/Mesa/src/glu/sgi/libnurbs/internals/trimline.cc,v 1.2 2005/10/28 13:09:23 brianp Exp $
  40  */
  41
  42 #include "glimports.h"
  43 #include "myassert.h"
  44 #include "mystdio.h"
  45 #include "trimline.h"
  46 #include "backend.h"
  47
  48 Trimline::Trimline()
  49 {
  50     size = 0; pts = 0; numverts = 0;
  51     tinterp = &t; binterp = &b;
  52 }
  53
  54 Trimline::~Trimline()
  55 {
  56     if( pts ) delete[] pts;
  57 }
  58
  59 void
  60 Trimline::init( TrimVertex *v )
  61 {
  62     reset();
  63     grow(1);
  64     append(v);
  65 }
  66
  67 inline void
  68 Trimline::grow( long npts )
  69 {
  70     if( size < npts ) {
  71         size = 2 * npts;
  72         if( pts ) delete[] pts;
  73         pts = new TrimVertex_p[size];
  74     }
  75 }
  76
  77 inline void
  78 Trimline::append( TrimVertex *v )
  79 {
  80     assert( numverts != size );
  81     pts[numverts++] = v;
  82 }
  83
  84 void
  85 Trimline::init( long npts, Arc_ptr jarc, long last )
  86 {
  87     jarcl.init( jarc, 0, last );
  88     grow( npts + 2 );
  89 }
  90
  91 inline void
  92 Trimline::swap()
  93 {
  94     TrimVertex *tmp=tinterp;
  95     tinterp=binterp;
  96     binterp=tmp;
  97 }
  98
  99 void
 100 Trimline::getNextPt()
 101 {
 102     *binterp = *jarcl.getnextpt();
 103 }
 104
 105 void
 106 Trimline::getPrevPt()
 107 {
 108     *binterp = *jarcl.getprevpt();
 109 }
 110
 111 /*----------------------------------------------------------------------
 112  * getNextPts - make arrays of pointers to trim points on left and right
 113  *              hulls of trim strip.
 114  *----------------------------------------------------------------------
 115  */
 116 void
 117 Trimline::getNextPts( REAL vval, Backend& backend )
 118 {
 119     reset(); swap(); append( tinterp );
 120     assert( tinterp->param[1] >= vval );
 121
 122     register TrimVertex *p;
 123     for( p=jarcl.getnextpt() ; p->param[1] >= vval; p=jarcl.getnextpt() ) {
 124         append( p );
 125     }
 126
 127     /* compute and copy pointer to final point on left hull */
 128     if( interpvert( last(), p, binterp, vval ) ) {
 129         binterp->nuid = p->nuid;
 130         backend.triangle( p, binterp, last() );
 131         append( binterp );
 132     }
 133     jarcl.reverse();
 134     (void) jarcl.getprevpt();   /* reset jarcl to proper position */
 135     jarcl.reverse();
 136 }
 137
 138 void
 139 Trimline::getPrevPts( REAL vval, Backend& backend )
 140 {
 141     reset(); swap(); append( tinterp );
 142     assert( tinterp->param[1] >= vval );
 143
 144     register TrimVertex *q;
 145     for( q=jarcl.getprevpt(); q->param[1] >= vval; q=jarcl.getprevpt() ) {
 146         append( q );
 147     }
 148
 149     /* compute and copy pointer to final point on right hull */
 150     if( interpvert( q, last(), binterp, vval ) ) {
 151         binterp->nuid = q->nuid;
 152         backend.triangle( last(), binterp, q );
 153         append( binterp );
 154     }
 155     jarcl.reverse();
 156     (void) jarcl.getnextpt();  /* reset jarcl to proper position */
 157     jarcl.reverse();
 158 }
 159
 160 void
 161 Trimline::getNextPts( Arc_ptr botarc )
 162 {
 163     reset(); swap(); append( tinterp );
 164
 165 #ifndef NDEBUG
 166     PwlArc *lastpwl = botarc->prev->pwlArc;
 167     TrimVertex *lastpt1 = &lastpwl->pts[lastpwl->npts-1];
 168 #endif
 169     TrimVertex *lastpt2 = botarc->pwlArc->pts;
 170     register TrimVertex *p = jarcl.getnextpt();
 171     for( append( p ); p != lastpt2; append( p ) ) {
 172         assert( p != lastpt1 );
 173         p = jarcl.getnextpt();
 174     }
 175 }
 176
 177 void
 178 Trimline::getPrevPts( Arc_ptr botarc )
 179 {
 180     reset();  swap(); append( tinterp );
 181
 182     PwlArc *lastpwl = botarc->prev->pwlArc;
 183     TrimVertex *lastpt1 = &lastpwl->pts[lastpwl->npts-1];
 184 #ifndef NDEBUG
 185     TrimVertex *lastpt2 = botarc->pwlArc->pts;
 186 #endif
 187
 188     register TrimVertex *q =  jarcl.getprevpt();
 189     for( append( q ); q != lastpt1; append( q ) ) {
 190         assert( q != lastpt2 );
 191         q = jarcl.getprevpt();
 192     }
 193 }
 194
 195
 196 long
 197 Trimline::interpvert( TrimVertex *a, TrimVertex *b, TrimVertex *c, REAL vval )
 198 {
 199     REAL denom = a->param[1] - b->param[1];
 200
 201     if(denom != 0) {
 202         if( vval == a->param[1] ) {
 203             c->param[0] = a->param[0];
 204             c->param[1] = a->param[1];
 205             c->nuid = a->nuid;
 206             return 0;
 207         } else if( vval == b->param[1] ) {
 208             c->param[0] = b->param[0];
 209             c->param[1] = b->param[1];
 210             c->nuid = b->nuid;
 211             return 0;
 212         } else {
 213             REAL r = (a->param[1] - vval)/denom;
 214             c->param[0] =  a->param[0] - r * (a->param[0] - b->param[0]);
 215             c->param[1] = vval;
 216             return 1;
 217         }
 218     } else {
 219         c->param[0] = a->param[0];
 220         c->param[1] = a->param[1];
 221         c->nuid = a->nuid;
 222         return 0;
 223     }
 224 }
 225