src/glu/sgi/libnurbs/internals/curve.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  * curve.c++
  37  *
  38  * $Date: 2001/03/17 00:25:40 $ $Revision: 1.1 $
  39  * $Header: /home/krh/git/sync/mesa-cvs-repo/Mesa/src/glu/sgi/libnurbs/internals/curve.cc,v 1.1 2001/03/17 00:25:40 brianp Exp $
  40  */
  41
  42 #include "glimports.h"
  43 #include "myassert.h"
  44 #include "mystdio.h"
  45 #include "mymath.h"
  46 #include "curve.h"
  47 #include "mapdesc.h"
  48 #include "types.h"
  49 #include "quilt.h"
  50 #include "nurbsconsts.h"
  51
  52 /*--------------------------------------------------------------------------
  53  * Curve::Curve - copy curve from quilt and transform control points
  54  *--------------------------------------------------------------------------
  55  */
  56
  57 Curve::Curve( Quilt_ptr geo, REAL pta, REAL ptb, Curve *c )
  58 {
  59     mapdesc = geo->mapdesc;
  60     next = c;
  61     needsSampling = mapdesc->isRangeSampling() ? 1 : 0;
  62     cullval = mapdesc->isCulling() ? CULL_ACCEPT : CULL_TRIVIAL_ACCEPT;
  63     order = geo->qspec[0].order;
  64     stride = MAXCOORDS;
  65
  66     REAL *ps  = geo->cpts;
  67     Quiltspec_ptr qs = geo->qspec;
  68     ps += qs->offset;
  69     ps += qs->index * qs->order * qs->stride;
  70     REAL *pend = ps + qs->order * qs->stride;
  71
  72     if( needsSampling )
  73         mapdesc->xformSampling( ps, qs->order, qs->stride, spts, stride );
  74
  75     if( cullval == CULL_ACCEPT )
  76         mapdesc->xformCulling(  ps, qs->order, qs->stride, cpts, stride );
  77
  78     /* set untrimmed curve range */
  79     range[0] = qs->breakpoints[qs->index];
  80     range[1] = qs->breakpoints[qs->index+1];
  81     range[2] = range[1] - range[0];
  82
  83     if( range[0] != pta ) {
  84         Curve lower( *this, pta, 0 );
  85         lower.next = next;
  86         *this = lower;
  87     }
  88     if( range[1] != ptb ) {
  89         Curve lower( *this, ptb, 0 );
  90     }
  91 }
  92
  93 /*--------------------------------------------------------------------------
  94  * Curve::Curve - subdivide a curve along an isoparametric line
  95  *--------------------------------------------------------------------------
  96  */
  97
  98 Curve::Curve( Curve& upper, REAL value, Curve *c )
  99 {
 100     Curve &lower = *this;
 101
 102     lower.next = c;
 103     lower.mapdesc = upper.mapdesc;
 104     lower.needsSampling = upper.needsSampling;
 105     lower.order = upper.order;
 106     lower.stride = upper.stride;
 107     lower.cullval = upper.cullval;
 108
 109     REAL d = (value - upper.range[0]) / upper.range[2];
 110
 111     if( needsSampling )
 112         mapdesc->subdivide( upper.spts, lower.spts, d, upper.stride, upper.order );
 113
 114     if( cullval == CULL_ACCEPT )
 115         mapdesc->subdivide( upper.cpts, lower.cpts, d, upper.stride, upper.order );
 116
 117     lower.range[0] = upper.range[0];
 118     lower.range[1] = value;
 119     lower.range[2] = value - upper.range[0];
 120     upper.range[0] = value;
 121     upper.range[2] = upper.range[1] - value;
 122 }
 123
 124
 125 /*--------------------------------------------------------------------------
 126  * Curve::clamp - clamp the sampling rate to a given maximum
 127  *--------------------------------------------------------------------------
 128  */
 129
 130 void
 131 Curve::clamp( void )
 132 {
 133     if( stepsize < minstepsize )
 134         stepsize = mapdesc->clampfactor * minstepsize;
 135 }
 136
 137 void
 138 Curve::setstepsize( REAL max )
 139 {
 140     stepsize = ( max >= 1.0 ) ? (range[2] / max) : range[2];
 141     minstepsize = stepsize;
 142 }
 143
 144 void
 145 Curve::getstepsize( void )
 146 {
 147     minstepsize= 0;
 148
 149     if( mapdesc->isConstantSampling() ) {
 150         // fixed number of samples per patch in each direction
 151         // maxrate is number of s samples per patch
 152         setstepsize( mapdesc->maxrate );
 153     } else if( mapdesc->isDomainSampling() ) {
 154         // maxrate is number of s samples per unit s length of domain
 155         setstepsize( mapdesc->maxrate * range[2] );
 156     } else {
 157         // upper bound on path length between sample points
 158
 159         assert( order <= MAXORDER );
 160
 161         /* points have been transformed, therefore they are homogeneous */
 162         REAL tmp[MAXORDER][MAXCOORDS];
 163         const int tstride = sizeof(tmp[0]) / sizeof(REAL);
 164         int val = mapdesc->project( spts, stride, &tmp[0][0], tstride,  order );
 165
 166         if( val == 0 ) {
 167             // control points cross infinity, therefore derivatives are undefined
 168             setstepsize( mapdesc->maxrate );
 169         } else {
 170             REAL t = mapdesc->getProperty( N_PIXEL_TOLERANCE );
 171             if( mapdesc->isParametricDistanceSampling() ) {
 172                 REAL d = mapdesc->calcPartialVelocity( &tmp[0][0], tstride, order, 2, range[2] );
 173                 stepsize = (d > 0.0) ? ::sqrtf( 8.0 * t / d ) : range[2];
 174                 minstepsize = ( mapdesc->maxrate > 0.0 ) ? (range[2] / mapdesc->maxrate) : 0.0;
 175             } else if( mapdesc->isPathLengthSampling() ) {
 176                 // t is upper bound on path (arc) length
 177                 REAL d = mapdesc->calcPartialVelocity( &tmp[0][0], tstride, order, 1, range[2] );
 178                 stepsize = ( d > 0.0 ) ? (t / d) : range[2];
 179                 minstepsize = ( mapdesc->maxrate > 0.0 ) ? (range[2] / mapdesc->maxrate) : 0.0;
 180             } else {
 181                 // control points cross infinity, therefore partials are undefined
 182                 setstepsize( mapdesc->maxrate );
 183             }
 184         }
 185     }
 186 }
 187
 188 int
 189 Curve::needsSamplingSubdivision( void )
 190 {
 191     return ( stepsize < minstepsize )  ? 1 : 0;
 192 }
 193
 194 int
 195 Curve::cullCheck( void )
 196 {
 197     if( cullval == CULL_ACCEPT )
 198         cullval = mapdesc->cullCheck( cpts, order, stride );
 199     return cullval;
 200 }
 201