reactos/dll/opengl/glu32/src/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  */
  39
  40 //#include "glimports.h"
  41 //#include "myassert.h"
  42 //#include "mystdio.h"
  43 #include "mymath.h"
  44 #include "curve.h"
  45 #include "mapdesc.h"
  46 //#include "types.h"
  47 #include "quilt.h"
  48 //#include "nurbsconsts.h"
  49
  50 /*--------------------------------------------------------------------------
  51  * Curve::Curve - copy curve from quilt and transform control points
  52  *--------------------------------------------------------------------------
  53  */
  54
  55 Curve::Curve( Quilt_ptr geo, REAL pta, REAL ptb, Curve *c )
  56 {
  57     mapdesc = geo->mapdesc;
  58     next = c;
  59     needsSampling = mapdesc->isRangeSampling() ? 1 : 0;
  60     cullval = mapdesc->isCulling() ? CULL_ACCEPT : CULL_TRIVIAL_ACCEPT;
  61     order = geo->qspec[0].order;
  62     stride = MAXCOORDS;
  63     for( int i = 0; i < MAXORDER * MAXCOORDS; i++ ) {
  64         cpts[i] = 0;
  65         spts[i] = 0;
  66     }
  67     stepsize = 0;
  68     minstepsize = 0;
  69
  70     REAL *ps  = geo->cpts;
  71     Quiltspec_ptr qs = geo->qspec;
  72     ps += qs->offset;
  73     ps += qs->index * qs->order * qs->stride;
  74
  75     if( needsSampling )
  76         mapdesc->xformSampling( ps, qs->order, qs->stride, spts, stride );
  77
  78     if( cullval == CULL_ACCEPT )
  79         mapdesc->xformCulling(  ps, qs->order, qs->stride, cpts, stride );
  80
  81     /* set untrimmed curve range */
  82     range[0] = qs->breakpoints[qs->index];
  83     range[1] = qs->breakpoints[qs->index+1];
  84     range[2] = range[1] - range[0];
  85
  86     if( range[0] != pta ) {
  87         Curve lower( *this, pta, 0 );
  88         lower.next = next;
  89         *this = lower;
  90     }
  91     if( range[1] != ptb ) {
  92         Curve lower( *this, ptb, 0 );
  93     }
  94 }
  95
  96 /*--------------------------------------------------------------------------
  97  * Curve::Curve - subdivide a curve along an isoparametric line
  98  *--------------------------------------------------------------------------
  99  */
 100
 101 Curve::Curve( Curve& upper, REAL value, Curve *c )
 102 {
 103     Curve &lower = *this;
 104
 105     lower.next = c;
 106     lower.mapdesc = upper.mapdesc;
 107     lower.needsSampling = upper.needsSampling;
 108     lower.order = upper.order;
 109     lower.stride = upper.stride;
 110     lower.cullval = upper.cullval;
 111
 112     REAL d = (value - upper.range[0]) / upper.range[2];
 113
 114     if( needsSampling )
 115         mapdesc->subdivide( upper.spts, lower.spts, d, upper.stride, upper.order );
 116
 117     if( cullval == CULL_ACCEPT )
 118         mapdesc->subdivide( upper.cpts, lower.cpts, d, upper.stride, upper.order );
 119
 120     lower.range[0] = upper.range[0];
 121     lower.range[1] = value;
 122     lower.range[2] = value - upper.range[0];
 123     upper.range[0] = value;
 124     upper.range[2] = upper.range[1] - value;
 125 }
 126
 127
 128 /*--------------------------------------------------------------------------
 129  * Curve::clamp - clamp the sampling rate to a given maximum
 130  *--------------------------------------------------------------------------
 131  */
 132
 133 void
 134 Curve::clamp( void )
 135 {
 136     if( stepsize < minstepsize )
 137         stepsize = mapdesc->clampfactor * minstepsize;
 138 }
 139
 140 void
 141 Curve::setstepsize( REAL max )
 142 {
 143     stepsize = ( max >= 1.0 ) ? (range[2] / max) : range[2];
 144     minstepsize = stepsize;
 145 }
 146
 147 void
 148 Curve::getstepsize( void )
 149 {
 150     minstepsize= 0;
 151
 152     if( mapdesc->isConstantSampling() ) {
 153         // fixed number of samples per patch in each direction
 154         // maxrate is number of s samples per patch
 155         setstepsize( mapdesc->maxrate );
 156     } else if( mapdesc->isDomainSampling() ) {
 157         // maxrate is number of s samples per unit s length of domain
 158         setstepsize( mapdesc->maxrate * range[2] );
 159     } else {
 160         // upper bound on path length between sample points
 161
 162         assert( order <= MAXORDER );
 163
 164         /* points have been transformed, therefore they are homogeneous */
 165         REAL tmp[MAXORDER][MAXCOORDS];
 166         const int tstride = sizeof(tmp[0]) / sizeof(REAL);
 167         int val = mapdesc->project( spts, stride, &tmp[0][0], tstride,  order );
 168
 169         if( val == 0 ) {
 170             // control points cross infinity, therefore derivatives are undefined
 171             setstepsize( mapdesc->maxrate );
 172         } else {
 173             REAL t = mapdesc->getProperty( N_PIXEL_TOLERANCE );
 174             if( mapdesc->isParametricDistanceSampling() ) {
 175                 REAL d = mapdesc->calcPartialVelocity( &tmp[0][0], tstride, order, 2, range[2] );
 176                 stepsize = (d > 0.0) ? sqrtf( 8.0 * t / d ) : range[2];
 177                 minstepsize = ( mapdesc->maxrate > 0.0 ) ? (range[2] / mapdesc->maxrate) : 0.0;
 178             } else if( mapdesc->isPathLengthSampling() ) {
 179                 // t is upper bound on path (arc) length
 180                 REAL d = mapdesc->calcPartialVelocity( &tmp[0][0], tstride, order, 1, range[2] );
 181                 stepsize = ( d > 0.0 ) ? (t / d) : range[2];
 182                 minstepsize = ( mapdesc->maxrate > 0.0 ) ? (range[2] / mapdesc->maxrate) : 0.0;
 183             } else {
 184                 // control points cross infinity, therefore partials are undefined
 185                 setstepsize( mapdesc->maxrate );
 186             }
 187         }
 188     }
 189 }
 190
 191 int
 192 Curve::needsSamplingSubdivision( void )
 193 {
 194     return ( stepsize < minstepsize )  ? 1 : 0;
 195 }
 196
 197 int
 198 Curve::cullCheck( void )
 199 {
 200     if( cullval == CULL_ACCEPT )
 201         cullval = mapdesc->cullCheck( cpts, order, stride );
 202     return cullval;
 203 }
 204