SGI SI GLU library

1 files changed, 201 insertions, 0 deletions

diff --git a/src/glu/sgi/libnurbs/internals/curve.cc b/src/glu/sgi/libnurbs/internals/curve.cc
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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++
+ *
+ * $Date: 2001/03/17 00:25:40 $ $Revision: 1.1 $
+ * $Header: /home/krh/git/sync/mesa-cvs-repo/Mesa/src/glu/sgi/libnurbs/internals/curve.cc,v 1.1 2001/03/17 00:25:40 brianp Exp $
+ */
+
+#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;
+    REAL *pend = ps + 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 );
+    }
+}
+
+/*--------------------------------------------------------------------------
+ * 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;
+}
+