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/*
** License Applicability. Except to the extent portions of this file are
** made subject to an alternative license as permitted in the SGI Free
** Software License B, Version 1.1 (the "License"), the contents of this
** file are subject only to the provisions of the License. You may not use
** this file except in compliance with the License. You may obtain a copy
** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
**
** http://oss.sgi.com/projects/FreeB
**
** Note that, as provided in the License, the Software is distributed on an
** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
**
** Original Code. The Original Code is: OpenGL Sample Implementation,
** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
** Copyright in any portions created by third parties is as indicated
** elsewhere herein. All Rights Reserved.
**
** Additional Notice Provisions: The application programming interfaces
** established by SGI in conjunction with the Original Code are The
** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
** Window System(R) (Version 1.3), released October 19, 1998. This software
** was created using the OpenGL(R) version 1.2.1 Sample Implementation
** published by SGI, but has not been independently verified as being
** compliant with the OpenGL(R) version 1.2.1 Specification.
*/
/*
* curve.c++
*
*/
#include "glimports.h"
#include "myassert.h"
#include "mystdio.h"
#include "mymath.h"
#include "curve.h"
#include "mapdesc.h"
#include "types.h"
#include "quilt.h"
#include "nurbsconsts.h"
/*--------------------------------------------------------------------------
* Curve::Curve - copy curve from quilt and transform control points
*--------------------------------------------------------------------------
*/
Curve::Curve( Quilt_ptr geo, REAL pta, REAL ptb, Curve *c )
{
mapdesc = geo->mapdesc;
next = c;
needsSampling = mapdesc->isRangeSampling() ? 1 : 0;
cullval = mapdesc->isCulling() ? CULL_ACCEPT : CULL_TRIVIAL_ACCEPT;
order = geo->qspec[0].order;
stride = MAXCOORDS;
REAL *ps = geo->cpts;
Quiltspec_ptr qs = geo->qspec;
ps += qs->offset;
ps += qs->index * qs->order * qs->stride;
if( needsSampling )
mapdesc->xformSampling( ps, qs->order, qs->stride, spts, stride );
if( cullval == CULL_ACCEPT )
mapdesc->xformCulling( ps, qs->order, qs->stride, cpts, stride );
/* set untrimmed curve range */
range[0] = qs->breakpoints[qs->index];
range[1] = qs->breakpoints[qs->index+1];
range[2] = range[1] - range[0];
if( range[0] != pta ) {
Curve lower( *this, pta, 0 );
lower.next = next;
*this = lower;
}
if( range[1] != ptb ) {
Curve lower( *this, ptb, 0 );
}
for( int i = 0; i < MAXORDER * MAXCOORDS; i++ ) {
cpts[i] = 0;
spts[i] = 0;
}
stepsize = 0;
minstepsize = 0;
}
/*--------------------------------------------------------------------------
* Curve::Curve - subdivide a curve along an isoparametric line
*--------------------------------------------------------------------------
*/
Curve::Curve( Curve& upper, REAL value, Curve *c )
{
Curve &lower = *this;
lower.next = c;
lower.mapdesc = upper.mapdesc;
lower.needsSampling = upper.needsSampling;
lower.order = upper.order;
lower.stride = upper.stride;
lower.cullval = upper.cullval;
REAL d = (value - upper.range[0]) / upper.range[2];
if( needsSampling )
mapdesc->subdivide( upper.spts, lower.spts, d, upper.stride, upper.order );
if( cullval == CULL_ACCEPT )
mapdesc->subdivide( upper.cpts, lower.cpts, d, upper.stride, upper.order );
lower.range[0] = upper.range[0];
lower.range[1] = value;
lower.range[2] = value - upper.range[0];
upper.range[0] = value;
upper.range[2] = upper.range[1] - value;
}
/*--------------------------------------------------------------------------
* Curve::clamp - clamp the sampling rate to a given maximum
*--------------------------------------------------------------------------
*/
void
Curve::clamp( void )
{
if( stepsize < minstepsize )
stepsize = mapdesc->clampfactor * minstepsize;
}
void
Curve::setstepsize( REAL max )
{
stepsize = ( max >= 1.0 ) ? (range[2] / max) : range[2];
minstepsize = stepsize;
}
void
Curve::getstepsize( void )
{
minstepsize= 0;
if( mapdesc->isConstantSampling() ) {
// fixed number of samples per patch in each direction
// maxrate is number of s samples per patch
setstepsize( mapdesc->maxrate );
} else if( mapdesc->isDomainSampling() ) {
// maxrate is number of s samples per unit s length of domain
setstepsize( mapdesc->maxrate * range[2] );
} else {
// upper bound on path length between sample points
assert( order <= MAXORDER );
/* points have been transformed, therefore they are homogeneous */
REAL tmp[MAXORDER][MAXCOORDS];
const int tstride = sizeof(tmp[0]) / sizeof(REAL);
int val = mapdesc->project( spts, stride, &tmp[0][0], tstride, order );
if( val == 0 ) {
// control points cross infinity, therefore derivatives are undefined
setstepsize( mapdesc->maxrate );
} else {
REAL t = mapdesc->getProperty( N_PIXEL_TOLERANCE );
if( mapdesc->isParametricDistanceSampling() ) {
REAL d = mapdesc->calcPartialVelocity( &tmp[0][0], tstride, order, 2, range[2] );
stepsize = (d > 0.0) ? sqrtf( 8.0 * t / d ) : range[2];
minstepsize = ( mapdesc->maxrate > 0.0 ) ? (range[2] / mapdesc->maxrate) : 0.0;
} else if( mapdesc->isPathLengthSampling() ) {
// t is upper bound on path (arc) length
REAL d = mapdesc->calcPartialVelocity( &tmp[0][0], tstride, order, 1, range[2] );
stepsize = ( d > 0.0 ) ? (t / d) : range[2];
minstepsize = ( mapdesc->maxrate > 0.0 ) ? (range[2] / mapdesc->maxrate) : 0.0;
} else {
// control points cross infinity, therefore partials are undefined
setstepsize( mapdesc->maxrate );
}
}
}
}
int
Curve::needsSamplingSubdivision( void )
{
return ( stepsize < minstepsize ) ? 1 : 0;
}
int
Curve::cullCheck( void )
{
if( cullval == CULL_ACCEPT )
cullval = mapdesc->cullCheck( cpts, order, stride );
return cullval;
}
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