reactos/dll/opengl/mesa/src/glu/sgi/libnurbs/internals/patch.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  * patch.c++
  37  *
  38  */
  39
  40 #include <stdio.h>
  41 #include "glimports.h"
  42 #include "mystdio.h"
  43 #include "myassert.h"
  44 #include "mymath.h"
  45 #include "mystring.h"
  46 #include "patch.h"
  47 #include "mapdesc.h"
  48 #include "quilt.h"
  49 #include "nurbsconsts.h"
  50 #include "simplemath.h" //for glu_abs function in ::singleStep();
  51
  52
  53 /*--------------------------------------------------------------------------
  54  * Patch - copy patch from quilt and transform control points
  55  *--------------------------------------------------------------------------
  56  */
  57
  58 Patch::Patch( Quilt_ptr geo, REAL *pta, REAL *ptb, Patch *n )
  59 {
  60 /* pspec[i].range is uninit here */
  61     mapdesc = geo->mapdesc;
  62     cullval = mapdesc->isCulling() ? CULL_ACCEPT : CULL_TRIVIAL_ACCEPT;
  63     notInBbox = mapdesc->isBboxSubdividing() ? 1 : 0;
  64     needsSampling = mapdesc->isRangeSampling() ? 1 : 0;
  65     pspec[0].order = geo->qspec[0].order;
  66     pspec[1].order = geo->qspec[1].order;
  67     pspec[0].stride = pspec[1].order * MAXCOORDS;
  68     pspec[1].stride = MAXCOORDS;
  69
  70     /* transform control points to sampling and culling spaces */
  71     REAL *ps  = geo->cpts;
  72     geo->select( pta, ptb );
  73     ps += geo->qspec[0].offset;
  74     ps += geo->qspec[1].offset;
  75     ps += geo->qspec[0].index * geo->qspec[0].order * geo->qspec[0].stride;
  76     ps += geo->qspec[1].index * geo->qspec[1].order * geo->qspec[1].stride;
  77
  78     if( needsSampling ) {
  79         mapdesc->xformSampling( ps, geo->qspec[0].order, geo->qspec[0].stride,
  80                                 geo->qspec[1].order, geo->qspec[1].stride,
  81                                 spts, pspec[0].stride, pspec[1].stride );
  82     }
  83
  84     if( cullval == CULL_ACCEPT  ) {
  85         mapdesc->xformCulling( ps, geo->qspec[0].order, geo->qspec[0].stride,
  86                                geo->qspec[1].order, geo->qspec[1].stride,
  87                                cpts, pspec[0].stride, pspec[1].stride );
  88     }
  89
  90     if( notInBbox ) {
  91         mapdesc->xformBounding( ps, geo->qspec[0].order, geo->qspec[0].stride,
  92                                geo->qspec[1].order, geo->qspec[1].stride,
  93                                bpts, pspec[0].stride, pspec[1].stride );
  94     }
  95
  96     /* set scale range */
  97     pspec[0].range[0] = geo->qspec[0].breakpoints[geo->qspec[0].index];
  98     pspec[0].range[1] = geo->qspec[0].breakpoints[geo->qspec[0].index+1];
  99     pspec[0].range[2] = pspec[0].range[1] - pspec[0].range[0];
 100
 101     pspec[1].range[0] = geo->qspec[1].breakpoints[geo->qspec[1].index];
 102     pspec[1].range[1] = geo->qspec[1].breakpoints[geo->qspec[1].index+1];
 103     pspec[1].range[2] = pspec[1].range[1] - pspec[1].range[0];
 104
 105     // may need to subdivide to match range of sub-patch
 106     if( pspec[0].range[0] != pta[0] ) {
 107         assert( pspec[0].range[0] < pta[0] );
 108         Patch lower( *this, 0, pta[0], 0 );
 109         *this = lower;
 110     }
 111
 112     if( pspec[0].range[1] != ptb[0] ) {
 113         assert( pspec[0].range[1] > ptb[0] );
 114         Patch upper( *this, 0, ptb[0], 0 );
 115     }
 116
 117     if( pspec[1].range[0] != pta[1] ) {
 118         assert( pspec[1].range[0] < pta[1] );
 119         Patch lower( *this, 1, pta[1], 0 );
 120         *this = lower;
 121     }
 122
 123     if( pspec[1].range[1] != ptb[1] ) {
 124         assert( pspec[1].range[1] > ptb[1] );
 125         Patch upper( *this, 1, ptb[1], 0 );
 126     }
 127     checkBboxConstraint();
 128     next = n;
 129 }
 130
 131 /*--------------------------------------------------------------------------
 132  * Patch - subdivide a patch along an isoparametric line
 133  *--------------------------------------------------------------------------
 134  */
 135
 136 Patch::Patch( Patch& upper, int param, REAL value, Patch *n )
 137 {
 138     Patch& lower = *this;
 139
 140     lower.cullval = upper.cullval;
 141     lower.mapdesc = upper.mapdesc;
 142     lower.notInBbox = upper.notInBbox;
 143     lower.needsSampling = upper.needsSampling;
 144     lower.pspec[0].order = upper.pspec[0].order;
 145     lower.pspec[1].order = upper.pspec[1].order;
 146     lower.pspec[0].stride = upper.pspec[0].stride;
 147     lower.pspec[1].stride = upper.pspec[1].stride;
 148     lower.next = n;
 149
 150     /* reset scale range */
 151     switch( param ) {
 152         case 0: {
 153             REAL d = (value-upper.pspec[0].range[0]) / upper.pspec[0].range[2];
 154             if( needsSampling )
 155                 mapdesc->subdivide( upper.spts, lower.spts, d, pspec[1].order,
 156                         pspec[1].stride, pspec[0].order, pspec[0].stride );
 157
 158             if( cullval == CULL_ACCEPT )
 159                 mapdesc->subdivide( upper.cpts, lower.cpts, d, pspec[1].order,
 160                         pspec[1].stride, pspec[0].order, pspec[0].stride );
 161
 162             if( notInBbox )
 163                 mapdesc->subdivide( upper.bpts, lower.bpts, d, pspec[1].order,
 164                         pspec[1].stride, pspec[0].order, pspec[0].stride );
 165
 166             lower.pspec[0].range[0] = upper.pspec[0].range[0];
 167             lower.pspec[0].range[1] = value;
 168             lower.pspec[0].range[2] = value - upper.pspec[0].range[0];
 169             upper.pspec[0].range[0] = value;
 170             upper.pspec[0].range[2] = upper.pspec[0].range[1] - value;
 171
 172             lower.pspec[1].range[0] = upper.pspec[1].range[0];
 173             lower.pspec[1].range[1] = upper.pspec[1].range[1];
 174             lower.pspec[1].range[2] = upper.pspec[1].range[2];
 175             break;
 176         }
 177         case 1: {
 178             REAL d = (value-upper.pspec[1].range[0]) / upper.pspec[1].range[2];
 179             if( needsSampling )
 180                 mapdesc->subdivide( upper.spts, lower.spts, d, pspec[0].order,
 181                         pspec[0].stride, pspec[1].order, pspec[1].stride );
 182             if( cullval == CULL_ACCEPT )
 183                 mapdesc->subdivide( upper.cpts, lower.cpts, d, pspec[0].order,
 184                         pspec[0].stride, pspec[1].order, pspec[1].stride );
 185             if( notInBbox )
 186                 mapdesc->subdivide( upper.bpts, lower.bpts, d, pspec[0].order,
 187                         pspec[0].stride, pspec[1].order, pspec[1].stride );
 188             lower.pspec[0].range[0] = upper.pspec[0].range[0];
 189             lower.pspec[0].range[1] = upper.pspec[0].range[1];
 190             lower.pspec[0].range[2] = upper.pspec[0].range[2];
 191
 192             lower.pspec[1].range[0] = upper.pspec[1].range[0];
 193             lower.pspec[1].range[1] = value;
 194             lower.pspec[1].range[2] = value - upper.pspec[1].range[0];
 195             upper.pspec[1].range[0] = value;
 196             upper.pspec[1].range[2] = upper.pspec[1].range[1] - value;
 197             break;
 198         }
 199     }
 200
 201     // inherit bounding box
 202     if( mapdesc->isBboxSubdividing() && ! notInBbox )
 203         memcpy( lower.bb, upper.bb, sizeof( bb ) );
 204
 205     lower.checkBboxConstraint();
 206     upper.checkBboxConstraint();
 207 }
 208
 209 /*--------------------------------------------------------------------------
 210  * clamp - clamp the sampling rate to a given maximum
 211  *--------------------------------------------------------------------------
 212  */
 213
 214 void
 215 Patch::clamp( void )
 216 {
 217     if( mapdesc->clampfactor != N_NOCLAMPING ) {
 218         pspec[0].clamp( mapdesc->clampfactor );
 219         pspec[1].clamp( mapdesc->clampfactor );
 220     }
 221 }
 222
 223 void
 224 Patchspec::clamp( REAL clampfactor )
 225 {
 226     if( sidestep[0] < minstepsize )
 227         sidestep[0] = clampfactor * minstepsize;
 228     if( sidestep[1] < minstepsize )
 229         sidestep[1] = clampfactor * minstepsize;
 230     if( stepsize < minstepsize )
 231         stepsize = clampfactor * minstepsize;
 232 }
 233
 234 void
 235 Patch::checkBboxConstraint( void )
 236 {
 237     if( notInBbox &&
 238         mapdesc->bboxTooBig( bpts, pspec[0].stride, pspec[1].stride,
 239                                    pspec[0].order, pspec[1].order, bb ) != 1 ) {
 240         notInBbox = 0;
 241     }
 242 }
 243
 244 void
 245 Patch::bbox( void )
 246 {
 247     if( mapdesc->isBboxSubdividing() )
 248         mapdesc->surfbbox( bb );
 249 }
 250
 251 /*--------------------------------------------------------------------------
 252  * getstepsize - compute the sampling density across the patch
 253  *              and determine if patch needs to be subdivided
 254  *--------------------------------------------------------------------------
 255  */
 256
 257 void
 258 Patch::getstepsize( void )
 259 {
 260     pspec[0].minstepsize = pspec[1].minstepsize = 0;
 261     pspec[0].needsSubdivision = pspec[1].needsSubdivision = 0;
 262
 263     if( mapdesc->isConstantSampling() ) {
 264         // fixed number of samples per patch in each direction
 265         // maxsrate is number of s samples per patch
 266         // maxtrate is number of t samples per patch
 267         pspec[0].getstepsize( mapdesc->maxsrate );
 268         pspec[1].getstepsize( mapdesc->maxtrate );
 269
 270     } else if( mapdesc->isDomainSampling() ) {
 271         // maxsrate is number of s samples per unit s length of domain
 272         // maxtrate is number of t samples per unit t length of domain
 273         pspec[0].getstepsize( mapdesc->maxsrate * pspec[0].range[2] );
 274         pspec[1].getstepsize( mapdesc->maxtrate * pspec[1].range[2] );
 275
 276     } else if( ! needsSampling ) {
 277         pspec[0].singleStep();
 278         pspec[1].singleStep();
 279     } else {
 280         // upper bound on path length between sample points
 281         REAL tmp[MAXORDER][MAXORDER][MAXCOORDS];
 282         const int trstride = sizeof(tmp[0]) / sizeof(REAL);
 283         const int tcstride = sizeof(tmp[0][0]) / sizeof(REAL);
 284
 285         assert( pspec[0].order <= MAXORDER );
 286
 287         /* points have been transformed, therefore they are homogeneous */
 288
 289         int val = mapdesc->project( spts, pspec[0].stride, pspec[1].stride,
 290                  &tmp[0][0][0], trstride, tcstride,
 291                  pspec[0].order, pspec[1].order );
 292         if( val == 0 ) {
 293             // control points cross infinity, therefore partials are undefined
 294             pspec[0].getstepsize( mapdesc->maxsrate );
 295             pspec[1].getstepsize( mapdesc->maxtrate );
 296         } else {
 297             REAL t1 = mapdesc->getProperty( N_PIXEL_TOLERANCE );
 298 //          REAL t2 = mapdesc->getProperty( N_ERROR_TOLERANCE );
 299             pspec[0].minstepsize = ( mapdesc->maxsrate > 0.0 ) ?
 300                         (pspec[0].range[2] / mapdesc->maxsrate) : 0.0;
 301             pspec[1].minstepsize = ( mapdesc->maxtrate > 0.0 ) ?
 302                         (pspec[1].range[2] / mapdesc->maxtrate) : 0.0;
 303             if( mapdesc->isParametricDistanceSampling() ||
 304                 mapdesc->isObjectSpaceParaSampling() ) {
 305
 306                 REAL t2;
 307                 t2 = mapdesc->getProperty( N_ERROR_TOLERANCE );
 308
 309                 // t2 is upper bound on the distance between surface and tessellant
 310                 REAL ssv[2], ttv[2];
 311                 REAL ss = mapdesc->calcPartialVelocity( ssv, &tmp[0][0][0], trstride, tcstride, pspec[0].order, pspec[1].order, 2, 0, pspec[0].range[2], pspec[1].range[2], 0 );
 312                 REAL st = mapdesc->calcPartialVelocity(   0, &tmp[0][0][0], trstride, tcstride, pspec[0].order, pspec[1].order, 1, 1, pspec[0].range[2], pspec[1].range[2], -1 );
 313                 REAL tt = mapdesc->calcPartialVelocity( ttv, &tmp[0][0][0], trstride, tcstride, pspec[0].order, pspec[1].order, 0, 2, pspec[0].range[2], pspec[1].range[2], 1 );
 314                 //make sure that ss st and tt are nonnegative:
 315                 if(ss <0) ss = -ss;
 316                 if(st <0) st = -st;
 317                 if(tt <0) tt = -tt;
 318
 319                 if( ss != 0.0 && tt != 0.0 ) {
 320                     /* printf( "ssv[0] %g ssv[1] %g ttv[0] %g ttv[1] %g\n",
 321                         ssv[0], ssv[1], ttv[0], ttv[1] ); */
 322                     REAL ttq = sqrtf( (float) ss );
 323                     REAL ssq = sqrtf( (float) tt );
 324                     REAL ds = sqrtf( 4 * t2 * ttq / ( ss * ttq + st * ssq ) );
 325                     REAL dt = sqrtf( 4 * t2 * ssq / ( tt * ssq + st * ttq ) );
 326                     pspec[0].stepsize = ( ds < pspec[0].range[2] ) ? ds : pspec[0].range[2];
 327                     REAL scutoff = 2.0 * t2 / ( pspec[0].range[2] * pspec[0].range[2]);
 328                     pspec[0].sidestep[0] = (ssv[0] > scutoff) ? sqrtf( 2.0 * t2 / ssv[0] ) : pspec[0].range[2];
 329                     pspec[0].sidestep[1] = (ssv[1] > scutoff) ? sqrtf( 2.0 * t2 / ssv[1] ) : pspec[0].range[2];
 330
 331                     pspec[1].stepsize = ( dt < pspec[1].range[2] ) ? dt : pspec[1].range[2];
 332                     REAL tcutoff = 2.0 * t2 / ( pspec[1].range[2] * pspec[1].range[2]);
 333                     pspec[1].sidestep[0] = (ttv[0] > tcutoff) ? sqrtf( 2.0 * t2 / ttv[0] ) : pspec[1].range[2];
 334                     pspec[1].sidestep[1] = (ttv[1] > tcutoff) ? sqrtf( 2.0 * t2 / ttv[1] ) : pspec[1].range[2];
 335                 } else if( ss != 0.0 ) {
 336                     REAL x = pspec[1].range[2] * st;
 337                     REAL ds = ( sqrtf( x * x + 8.0 * t2 * ss ) - x ) / ss;
 338                     pspec[0].stepsize = ( ds < pspec[0].range[2] ) ? ds : pspec[0].range[2];
 339                     REAL scutoff = 2.0 * t2 / ( pspec[0].range[2] * pspec[0].range[2]);
 340                     pspec[0].sidestep[0] = (ssv[0] > scutoff) ? sqrtf( 2.0 * t2 / ssv[0] ) : pspec[0].range[2];
 341                     pspec[0].sidestep[1] = (ssv[1] > scutoff) ? sqrtf( 2.0 * t2 / ssv[1] ) : pspec[0].range[2];
 342                     pspec[1].singleStep();
 343                 } else if( tt != 0.0 ) {
 344                     REAL x = pspec[0].range[2] * st;
 345                     REAL dt = ( sqrtf( x * x + 8.0 * t2 * tt ) - x )  / tt;
 346                     pspec[0].singleStep();
 347                     REAL tcutoff = 2.0 * t2 / ( pspec[1].range[2] * pspec[1].range[2]);
 348                     pspec[1].stepsize = ( dt < pspec[1].range[2] ) ? dt : pspec[1].range[2];
 349                     pspec[1].sidestep[0] = (ttv[0] > tcutoff) ? sqrtf( 2.0 * t2 / ttv[0] ) : pspec[1].range[2];
 350                     pspec[1].sidestep[1] = (ttv[1] > tcutoff) ? sqrtf( 2.0 * t2 / ttv[1] ) : pspec[1].range[2];
 351                 } else {
 352                     if( 4.0 * t2  > st * pspec[0].range[2] * pspec[1].range[2] ) {
 353                         pspec[0].singleStep();
 354                         pspec[1].singleStep();
 355                     } else {
 356                         REAL area = 4.0 * t2 / st;
 357                         REAL ds = sqrtf( area * pspec[0].range[2] / pspec[1].range[2] );
 358                         REAL dt = sqrtf( area * pspec[1].range[2] / pspec[0].range[2] );
 359                         pspec[0].stepsize = ( ds < pspec[0].range[2] ) ? ds : pspec[0].range[2];
 360                         pspec[0].sidestep[0] = pspec[0].range[2];
 361                         pspec[0].sidestep[1] = pspec[0].range[2];
 362
 363                         pspec[1].stepsize = ( dt < pspec[1].range[2] ) ? dt : pspec[1].range[2];
 364                         pspec[1].sidestep[0] = pspec[1].range[2];
 365                         pspec[1].sidestep[1] = pspec[1].range[2];
 366                     }
 367                 }
 368             } else if( mapdesc->isPathLengthSampling() ||
 369                       mapdesc->isObjectSpacePathSampling()) {
 370                 // t1 is upper bound on path length
 371                 REAL msv[2], mtv[2];
 372                 REAL ms = mapdesc->calcPartialVelocity( msv, &tmp[0][0][0], trstride, tcstride, pspec[0].order, pspec[1].order, 1, 0, pspec[0].range[2], pspec[1].range[2], 0 );
 373                 REAL mt = mapdesc->calcPartialVelocity( mtv, &tmp[0][0][0], trstride, tcstride, pspec[0].order, pspec[1].order, 0, 1, pspec[0].range[2], pspec[1].range[2], 1 );
 374                 REAL side_scale = 1.0;
 375
 376                 if( ms != 0.0 ) {
 377                     if( mt != 0.0 ) {
 378 /*                  REAL d = t1 / ( ms * ms + mt * mt );*/
 379 /*                  REAL ds = mt * d;*/
 380                     REAL ds = t1 / (2.0*ms);
 381 /*                  REAL dt = ms * d;*/
 382                     REAL dt = t1 / (2.0*mt);
 383                         pspec[0].stepsize = ( ds < pspec[0].range[2] ) ? ds : pspec[0].range[2];
 384                         pspec[0].sidestep[0] = ( msv[0] * pspec[0].range[2] > t1 ) ? (side_scale* t1 / msv[0]) : pspec[0].range[2];
 385                         pspec[0].sidestep[1] = ( msv[1] * pspec[0].range[2] > t1 ) ? (side_scale* t1 / msv[1]) : pspec[0].range[2];
 386
 387                         pspec[1].stepsize = ( dt < pspec[1].range[2] ) ? dt : pspec[1].range[2];
 388                         pspec[1].sidestep[0] = ( mtv[0] * pspec[1].range[2] > t1 ) ? (side_scale*t1 / mtv[0]) : pspec[1].range[2];
 389                         pspec[1].sidestep[1] = ( mtv[1] * pspec[1].range[2] > t1 ) ? (side_scale*t1 / mtv[1]) : pspec[1].range[2];
 390                     } else {
 391                         pspec[0].stepsize = ( t1 < ms * pspec[0].range[2] ) ? (t1 / ms) : pspec[0].range[2];
 392                         pspec[0].sidestep[0] = ( msv[0] * pspec[0].range[2] > t1 ) ? (t1 / msv[0]) : pspec[0].range[2];
 393                         pspec[0].sidestep[1] = ( msv[1] * pspec[0].range[2] > t1 ) ? (t1 / msv[1]) : pspec[0].range[2];
 394
 395                         pspec[1].singleStep();
 396                     }
 397                 } else {
 398                     if( mt != 0.0 ) {
 399                         pspec[0].singleStep();
 400
 401                         pspec[1].stepsize = ( t1 < mt * pspec[1].range[2] ) ? (t1 / mt) : pspec[1].range[2];
 402                         pspec[1].sidestep[0] = ( mtv[0] * pspec[1].range[2] > t1 ) ? (t1 / mtv[0]) : pspec[1].range[2];
 403                         pspec[1].sidestep[1] = ( mtv[1] * pspec[1].range[2] > t1 ) ? (t1 / mtv[1]) : pspec[1].range[2];
 404                     } else {
 405                         pspec[0].singleStep();
 406                         pspec[1].singleStep();
 407                     }
 408                 }
 409             } else if( mapdesc->isSurfaceAreaSampling() ) {
 410                 // t is the square root of area
 411 /*
 412                 REAL msv[2], mtv[2];
 413                 REAL ms = mapdesc->calcPartialVelocity( msv, &tmp[0][0][0], trstride, tcstride, pspec[0].order, pspec[1].order, 1, 0, pspec[0].range[2], pspec[1].range[2], 0 );
 414                 REAL mt = mapdesc->calcPartialVelocity( mtv, &tmp[0][0][0], trstride, tcstride, pspec[0].order, pspec[1].order, 0, 1, pspec[0].range[2], pspec[1].range[2], 1 );
 415                 if( ms != 0.0 &&  mt != 0.0 ) {
 416                         REAL d = 1.0 / (ms * mt);
 417                         t *= M_SQRT2;
 418                         REAL ds = t * sqrtf( d * pspec[0].range[2] / pspec[1].range[2] );
 419                         REAL dt = t * sqrtf( d * pspec[1].range[2] / pspec[0].range[2] );
 420                         pspec[0].stepsize = ( ds < pspec[0].range[2] ) ? ds : pspec[0].range[2];
 421                         pspec[0].sidestep[0] = ( msv[0] * pspec[0].range[2] > t ) ? (t / msv[0]) : pspec[0].range[2];
 422                         pspec[0].sidestep[1] = ( msv[1] * pspec[0].range[2] > t ) ? (t / msv[1]) : pspec[0].range[2];
 423
 424                         pspec[1].stepsize = ( dt < pspec[1].range[2] ) ? dt : pspec[1].range[2];
 425                         pspec[1].sidestep[0] = ( mtv[0] * pspec[1].range[2] > t ) ? (t / mtv[0]) : pspec[1].range[2];
 426                         pspec[1].sidestep[1] = ( mtv[1] * pspec[1].range[2] > t ) ? (t / mtv[1]) : pspec[1].range[2];
 427                 } else {
 428                     pspec[0].singleStep();
 429                     pspec[1].singleStep();
 430                 }
 431 */
 432             } else {
 433                 pspec[0].singleStep();
 434                 pspec[1].singleStep();
 435             }
 436         }
 437     }
 438
 439 #ifdef DEBUG
 440     _glu_dprintf( "sidesteps %g %g %g %g, stepsize %g %g\n",
 441         pspec[0].sidestep[0], pspec[0].sidestep[1],
 442         pspec[1].sidestep[0], pspec[1].sidestep[1],
 443         pspec[0].stepsize, pspec[1].stepsize );
 444 #endif
 445
 446     if( mapdesc->minsavings != N_NOSAVINGSSUBDIVISION ) {
 447         REAL savings = 1./(pspec[0].stepsize * pspec[1].stepsize) ;
 448         savings-= (2./( pspec[0].sidestep[0] + pspec[0].sidestep[1] )) *
 449                   (2./( pspec[1].sidestep[0] + pspec[1].sidestep[1] ));
 450
 451         savings *= pspec[0].range[2] * pspec[1].range[2];
 452         if( savings > mapdesc->minsavings ) {
 453             pspec[0].needsSubdivision = pspec[1].needsSubdivision = 1;
 454         }
 455     }
 456
 457     if( pspec[0].stepsize < pspec[0].minstepsize )  pspec[0].needsSubdivision =  1;
 458     if( pspec[1].stepsize < pspec[1].minstepsize )  pspec[1].needsSubdivision =  1;
 459     needsSampling = (needsSampling ? needsSamplingSubdivision() : 0);
 460 }
 461
 462 void
 463 Patchspec::singleStep()
 464 {
 465     stepsize =  sidestep[0] =  sidestep[1] = glu_abs(range[2]);
 466 }
 467
 468 void
 469 Patchspec::getstepsize( REAL max ) // max is number of samples for entire patch
 470 {
 471     stepsize = ( max >= 1.0 ) ? range[2] / max : range[2];
 472     if (stepsize < 0.0) {
 473        stepsize = -stepsize;
 474     }
 475     sidestep[0] =  sidestep[1] = minstepsize = stepsize;
 476 }
 477
 478 int
 479 Patch::needsSamplingSubdivision( void )
 480 {
 481     return (pspec[0].needsSubdivision || pspec[1].needsSubdivision) ? 1 : 0;
 482 }
 483
 484 int
 485 Patch::needsNonSamplingSubdivision( void )
 486 {
 487     return notInBbox;
 488 }
 489
 490 int
 491 Patch::needsSubdivision( int param )
 492 {
 493     return pspec[param].needsSubdivision;
 494 }
 495
 496 int
 497 Patch::cullCheck( void )
 498 {
 499     if( cullval == CULL_ACCEPT )
 500         cullval = mapdesc->cullCheck( cpts, pspec[0].order,  pspec[0].stride,
 501                                             pspec[1].order,  pspec[1].stride );
 502     return cullval;
 503 }
 504