reactos/dll/glu32/libnurbs/internals/hull.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  * hull.c++
  37  *
  38  * $Date$ $Revision: 1.1 $
  39  * $Header: /cygdrive/c/RCVS/CVS/ReactOS/reactos/lib/glu32/libnurbs/internals/hull.cc,v 1.1 2004/02/02 16:39:11 navaraf Exp $
  40  */
  41
  42 #include "glimports.h"
  43 #include "myassert.h"
  44 #include "mystdio.h"
  45 #include "hull.h"
  46 #include "gridvertex.h"
  47 #include "gridtrimvertex.h"
  48 #include "gridline.h"
  49 #include "trimline.h"
  50 #include "uarray.h"
  51 #include "trimregion.h"
  52
  53 Hull::Hull( void )
  54 {}
  55
  56 Hull::~Hull( void )
  57 {}
  58
  59 /*----------------------------------------------------------------------
  60  * Hull:init - this routine does the initialization needed before any
  61  *              calls to nextupper or nextlower can be made.
  62  *----------------------------------------------------------------------
  63  */
  64 void
  65 Hull::init( void )
  66 {
  67     TrimVertex *lfirst = left.first();
  68     TrimVertex *llast = left.last();
  69     if( lfirst->param[0] <= llast->param[0] ) {
  70         fakeleft.init( left.first() );
  71         upper.left = &fakeleft;
  72         lower.left = &left;
  73     } else {
  74         fakeleft.init( left.last() );
  75         lower.left = &fakeleft;
  76         upper.left = &left;
  77     }
  78     upper.left->last();
  79     lower.left->first();
  80
  81     if( top.ustart <= top.uend ) {
  82         upper.line = &top;
  83         upper.index = top.ustart;
  84     } else
  85         upper.line = 0;
  86
  87     if( bot.ustart <= bot.uend ) {
  88         lower.line = &bot;
  89         lower.index = bot.ustart;
  90     } else
  91         lower.line = 0;
  92
  93     TrimVertex *rfirst = right.first();
  94     TrimVertex *rlast = right.last();
  95     if( rfirst->param[0] <= rlast->param[0] ) {
  96         fakeright.init( right.last() );
  97         lower.right = &fakeright;
  98         upper.right = &right;
  99     } else {
 100         fakeright.init( right.first() );
 101         upper.right = &fakeright;
 102         lower.right = &right;
 103     }
 104     upper.right->first();
 105     lower.right->last();
 106 }
 107
 108 /*----------------------------------------------------------------------
 109  * nextupper - find next vertex on upper hull of trim region.
 110  *               - if vertex is on trim curve, set vtop point to
 111  *                 that vertex.  if vertex is on grid, set vtop to
 112  *                 point to temporary area and stuff coordinants into
 113  *                 temporary vertex.  Also, place grid coords in temporary
 114  *                 grid vertex.
 115  *----------------------------------------------------------------------
 116  */
 117 GridTrimVertex *
 118 Hull::nextupper( GridTrimVertex *gv )
 119 {
 120     if( upper.left ) {
 121         gv->set( upper.left->prev() );
 122         if( gv->isTrimVert() ) return gv;
 123         upper.left = 0;
 124     }
 125
 126     if( upper.line ) {
 127         assert( upper.index <= upper.line->uend );
 128         gv->set( uarray.uarray[upper.index], upper.line->vval );
 129         gv->set( upper.index, upper.line->vindex );
 130         if( upper.index++ == upper.line->uend ) upper.line = 0;
 131         return gv;
 132     }
 133
 134     if( upper.right ) {
 135         gv->set( upper.right->next() );
 136         if( gv->isTrimVert() ) return gv;
 137         upper.right = 0;
 138     }
 139
 140     return 0;
 141 }
 142
 143 GridTrimVertex *
 144 Hull::nextlower( register GridTrimVertex *gv )
 145 {
 146     if( lower.left ) {
 147         gv->set( lower.left->next() );
 148         if( gv->isTrimVert() ) return gv;
 149         lower.left = 0;
 150     }
 151
 152     if( lower.line ) {
 153         gv->set( uarray.uarray[lower.index], lower.line->vval );
 154         gv->set( lower.index, lower.line->vindex );
 155         if( lower.index++ == lower.line->uend ) lower.line = 0;
 156         return gv;
 157     }
 158
 159     if( lower.right ) {
 160         gv->set( lower.right->prev() );
 161         if( gv->isTrimVert() ) return gv;
 162         lower.right = 0;
 163     }
 164
 165     return 0;
 166 }
 167