SGI SI GLU library

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diff --git a/src/glu/sgi/libnurbs/internals/monotonizer.cc b/src/glu/sgi/libnurbs/internals/monotonizer.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.
+*/
+
+/*
+ * monotonizer.c++
+ *
+ * $Date: 2001/03/17 00:25:41 $ $Revision: 1.1 $
+ * $Header: /home/krh/git/sync/mesa-cvs-repo/Mesa/src/glu/sgi/libnurbs/internals/monotonizer.cc,v 1.1 2001/03/17 00:25:41 brianp Exp $
+ */
+
+#include "glimports.h"
+#include "mystdio.h"
+#include "myassert.h"
+#include "arc.h"
+#include "arctess.h"
+#include "bezierarc.h"
+#include "bin.h"
+#include "mapdesc.h"
+#include "nurbsconsts.h"
+#include "subdivider.h"
+
+/*-----------------------------------------------------------------------------
+ * Subdivider::decompose - break all curves into monotone arcs
+ *-----------------------------------------------------------------------------
+ */
+int
+Subdivider::decompose( Bin& bin, REAL geo_stepsize )
+{
+    Arc_ptr jarc;
+    for( jarc=bin.firstarc(); jarc; jarc=bin.nextarc() ) {
+	if( ! jarc->isTessellated() ) {
+	    /* points have not been transformed, therefore they may be either
+	       homogeneous or inhomogeneous */
+	    tessellate( jarc, geo_stepsize );
+	    if( jarc->isDisconnected() || jarc->next->isDisconnected() ) 
+		return 1;
+	}
+    }
+
+    for( jarc=bin.firstarc(); jarc; jarc=bin.nextarc() ) {
+	monotonize( jarc, bin );
+    }
+
+#ifndef NDEBUG
+    for( jarc=bin.firstarc(); jarc; jarc=bin.nextarc() ) {
+	assert( isMonotone( jarc ) != 0 );
+    }
+#endif
+
+    return 0;
+}
+
+void
+Subdivider::tessellate( Arc_ptr jarc, REAL geo_stepsize )
+{
+    BezierArc *b = jarc->bezierArc;
+    Mapdesc *mapdesc = b->mapdesc;
+
+    if( mapdesc->isRational() ) {
+	REAL max = mapdesc->calcVelocityRational( b->cpts, b->stride, b->order );
+	REAL arc_stepsize = (max > 1.0) ? (1.0/max) : 1.0; 
+	if( jarc->bezierArc->order != 2 )
+	    arctessellator.tessellateNonlinear( jarc, geo_stepsize, arc_stepsize, 1 );
+	else {
+	    arctessellator.tessellateLinear( jarc, geo_stepsize, arc_stepsize, 1 );
+	}
+    } else { 
+	REAL max = mapdesc->calcVelocityNonrational( b->cpts, b->stride, b->order );
+	REAL arc_stepsize = (max > 1.0) ? (1.0/max) : 1.0; 
+	if( jarc->bezierArc->order != 2 )
+	    arctessellator.tessellateNonlinear( jarc, geo_stepsize, arc_stepsize, 0 );
+	else {
+	    arctessellator.tessellateLinear( jarc, geo_stepsize, arc_stepsize, 0 );
+	}
+    }
+}
+
+/*-------------------------------------------------------------------------
+ * Subdivider::monotonize - break up a jordan arc into s,t-monotone
+ *	components.  This code will remove degenerate segments, including
+ *	arcs of only a single point.
+ *-------------------------------------------------------------------------
+ */
+void
+Subdivider::monotonize( Arc_ptr jarc, Bin& bin )
+{
+    TrimVertex  *firstvert = jarc->pwlArc->pts;
+    TrimVertex  *lastvert = firstvert + (jarc->pwlArc->npts - 1);
+    long	uid = jarc->nuid;
+    arc_side	side = jarc->getside();
+    dir		sdir = none;
+    dir		tdir = none;
+    int 	degenerate = 1;
+
+    int		nudegenerate;
+    int		change;
+
+    TrimVertex *vert;
+    for( vert = firstvert; vert != lastvert; vert++ ) {
+
+        nudegenerate = 1;
+        change = 0;
+
+	/* check change relative to s axis, clear degenerate bit if needed */
+        REAL sdiff = vert[1].param[0] - vert[0].param[0]; 
+        if( sdiff == 0 ) {
+	    if( sdir != same ) {
+	        sdir = same;
+		change = 1;
+	    }
+        } else if( sdiff < 0.0 ) {
+	    if( sdir != down ) {
+	        sdir = down;
+		change = 1;
+	    }
+	    nudegenerate = 0;
+        } else {
+	    if( sdir != up ) {
+	        sdir = up;
+		change = 1;
+	    }
+	    nudegenerate = 0;
+        }
+    
+	/* check change relative to t axis, clear degenerate bit if needed */
+        REAL tdiff = vert[1].param[1] - vert[0].param[1]; 
+        if( tdiff == 0 ) { 
+	    if( tdir != same ) {
+	        tdir = same;
+	 	change = 1;
+	    }
+        } else if( tdiff < 0.0 ) {
+	    if( tdir != down ) {
+	        tdir = down;
+		change = 1;
+	    }
+	    nudegenerate = 0;
+        } else {
+	    if( tdir != up ) {
+	        tdir = up;
+		change = 1;
+	    }
+	    nudegenerate = 0;
+        }
+    
+	if( change ) {
+	    if( ! degenerate ) {
+	        /* make last segment into separate pwl curve */
+	        jarc->pwlArc->npts = vert - firstvert + 1;
+	        jarc = (new(arcpool) Arc( side, uid ))->append( jarc );
+	        jarc->pwlArc = new(pwlarcpool) PwlArc();
+		bin.addarc( jarc );
+	    }
+	    firstvert = jarc->pwlArc->pts = vert;
+	    degenerate = nudegenerate;
+	} 
+    }
+    jarc->pwlArc->npts = vert - firstvert + 1;
+
+    if( degenerate ) {
+	/* remove jarc from circularly linked list */
+	jarc->prev->next = jarc->next;
+	jarc->next->prev = jarc->prev;
+
+        assert( jarc->prev->check(  ) != 0 );
+        assert( jarc->next->check(  ) != 0 );
+
+	/* remove jarc from bin */
+	bin.remove_this_arc( jarc  );
+
+	jarc->pwlArc->deleteMe( pwlarcpool ); jarc->pwlArc = 0;
+	jarc->deleteMe( arcpool );
+    } 
+}
+
+/*-------------------------------------------------------------------------
+ * Subdivider::isMonotone - return true if arc is monotone AND non-degenerate
+ *-------------------------------------------------------------------------
+ */
+int
+Subdivider::isMonotone( Arc_ptr jarc )
+{
+    TrimVertex  *firstvert = jarc->pwlArc->pts;
+    TrimVertex  *lastvert = firstvert + (jarc->pwlArc->npts - 1);
+
+    if( firstvert == lastvert ) return 1;
+
+    TrimVertex	*vert = firstvert;
+    enum dir	sdir;
+    enum dir	tdir;
+
+    REAL diff = vert[1].param[0] - vert[0].param[0]; 
+    if( diff == 0.0 ) 
+        sdir = same;
+    else if( diff < 0.0 )
+        sdir = down;
+    else
+        sdir = up;
+
+    diff = vert[1].param[1] - vert[0].param[1]; 
+    if( diff == 0.0 ) 
+        tdir = same;
+    else if( diff < 0.0 )
+        tdir = down;
+    else
+        tdir = up;
+
+    if( (sdir == same) && (tdir == same) ) return 0;
+    
+    for( ++vert ; vert != lastvert; vert++ ) {
+        diff = vert[1].param[0] - vert[0].param[0]; 
+        if( diff == 0.0 ) {
+	    if( sdir != same ) return 0;
+        } else if( diff < 0.0 ) {
+	    if( sdir != down ) return 0;
+        } else {
+	    if( sdir != up ) return 0;
+        }
+
+        diff = vert[1].param[1] - vert[0].param[1]; 
+        if( diff == 0.0 ) {
+	    if( tdir != same ) return 0;
+        } else if( diff < 0.0 ) {
+	    if( tdir != down ) return 0;
+        } else {
+	    if( tdir != up ) return 0;
+        }
+    }
+    return 1;
+}
+