Windows2003-3790/multimedia/opengl/glu/nurbs/core/curvesub.cxx
2020-09-30 16:53:55 +02:00

82 lines
2.5 KiB
C++

/**************************************************************************
* *
* Copyright (C) 1992, Silicon Graphics, Inc. *
* *
* These coded instructions, statements, and computer programs contain *
* unpublished proprietary information of Silicon Graphics, Inc., and *
* are protected by Federal copyright law. They may not be disclosed *
* to third parties or copied or duplicated in any form, in whole or *
* in part, without the prior written consent of Silicon Graphics, Inc. *
* *
**************************************************************************/
/*
* curvesub.c++ - $Revision: 1.1 $
* Derrick Burns - 1991
*/
#include "glimport.h"
#include "myassert.h"
#include "mystdio.h"
#include "subdivid.h"
#include "renderhi.h"
#include "backend.h"
#include "quilt.h"
#include "curvelis.h"
#include "curve.h"
#include "nurbscon.h"
/*--------------------------------------------------------------------------
* drawCurves - main curve rendering entry point
*--------------------------------------------------------------------------
*/
void
Subdivider::drawCurves( void )
{
REAL from[1], to[1];
Flist bpts;
qlist->getRange( from, to, bpts );
renderhints.init( );
backend.bgncurv();
for( int i=bpts.start; i<bpts.end-1; i++ ) {
REAL pta, ptb;
pta = bpts.pts[i];
ptb = bpts.pts[i+1];
qlist->downloadAll( &pta, &ptb, backend );
Curvelist curvelist( qlist, pta, ptb );
samplingSplit( curvelist, renderhints.maxsubdivisions );
}
backend.endcurv();
}
/*--------------------------------------------------------------------------
* samplingSplit - recursively subdivide patch, cull check each subpatch
*--------------------------------------------------------------------------
*/
void
Subdivider::samplingSplit( Curvelist& curvelist, int subdivisions )
{
if( curvelist.cullCheck() == CULL_TRIVIAL_REJECT ) return;
curvelist.getstepsize();
if( curvelist.needsSamplingSubdivision() && (subdivisions > 0) ) {
REAL mid = ( curvelist.range[0] + curvelist.range[1] ) * 0.5;
Curvelist lowerlist( curvelist, mid );
samplingSplit( lowerlist, subdivisions-1 ); // lower
samplingSplit( curvelist, subdivisions-1 ); // upper
} else {
long nu = 1 + ((long) (curvelist.range[2] / curvelist.stepsize));
backend.curvgrid( curvelist.range[0], curvelist.range[1], nu );
backend.curvmesh( 0, nu );
}
}