SGI SI GLU library

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diff --git a/src/glu/sgi/libnurbs/internals/intersect.cc b/src/glu/sgi/libnurbs/internals/intersect.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.
+*/
+
+/*
+ * intersect.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/intersect.cc,v 1.1 2001/03/17 00:25:41 brianp Exp $
+ */
+
+#include "glimports.h"
+#include "myassert.h"
+#include "mystdio.h"
+#include "subdivider.h"
+#include "arc.h"
+#include "bin.h"
+#include "backend.h"
+#include "trimvertpool.h"
+
+/*#define NOTDEF*/
+
+enum i_result { INTERSECT_VERTEX, INTERSECT_EDGE };
+
+/* local functions */
+static int		arc_classify( Arc_ptr, int, REAL );
+static enum i_result	pwlarc_intersect( PwlArc *, int, REAL, int, int[3] );
+
+
+void
+Subdivider::partition( Bin & bin, Bin & left, Bin & intersections, 
+	        Bin & right, Bin & unknown, int param, REAL value )
+{
+    Bin	headonleft, headonright, tailonleft, tailonright;
+
+    for( Arc_ptr jarc = bin.removearc(); jarc; jarc = bin.removearc() ) {
+
+	REAL tdiff = jarc->tail()[param] - value;
+	REAL hdiff = jarc->head()[param] - value;
+
+	if( tdiff > 0.0 ) {
+	    if( hdiff > 0.0 ) {
+		right.addarc( jarc  );
+	    } else if( hdiff == 0.0 ) {
+		tailonright.addarc( jarc  );
+	    } else {
+	        Arc_ptr	jtemp;
+		switch( arc_split(jarc, param, value, 0) ) {
+		    case 2:
+			tailonright.addarc( jarc  );
+			headonleft.addarc( jarc->next  );
+			break;
+		    case 31:
+			assert( jarc->head()[param] > value );
+			right.addarc( jarc  );
+			tailonright.addarc( jtemp = jarc->next  );
+			headonleft.addarc( jtemp->next  );
+		        break;
+		    case 32:
+			assert( jarc->head()[param] <= value );
+			tailonright .addarc( jarc  );
+			headonleft.addarc( jtemp = jarc->next  );
+			left.addarc( jtemp->next  );
+			break;
+		    case 4:
+			right.addarc( jarc  );
+			tailonright.addarc( jtemp = jarc->next  );
+			headonleft.addarc( jtemp = jtemp->next  );
+			left.addarc( jtemp->next  );
+		}
+	    }
+	} else if( tdiff == 0.0 ) {
+	    if( hdiff > 0.0 ) {
+		headonright.addarc( jarc  );
+	    } else if( hdiff == 0.0 ) {
+		unknown.addarc( jarc  );
+	    } else {
+		headonleft.addarc( jarc  );
+	    }
+	} else {
+	    if( hdiff > 0.0 ) {
+	        Arc_ptr	jtemp;
+		switch( arc_split(jarc, param, value, 1) ) {
+		    case 2:
+			tailonleft.addarc( jarc  );
+			headonright.addarc( jarc->next  );
+			break;
+		    case 31:
+			assert( jarc->head()[param] < value );
+			left.addarc( jarc  );
+			tailonleft.addarc( jtemp = jarc->next  );
+			headonright.addarc( jtemp->next  );
+			break;
+		    case 32:
+			assert( jarc->head()[param] >= value );
+			tailonleft.addarc( jarc  );
+			headonright.addarc( jtemp = jarc->next  );
+			right.addarc( jtemp->next  );
+			break;
+		    case 4:
+			left.addarc( jarc  );
+			tailonleft.addarc( jtemp = jarc->next  );
+			headonright.addarc( jtemp = jtemp->next  );
+			right.addarc( jtemp->next  );
+		}
+	    } else if( hdiff == 0.0 ) {
+		tailonleft.addarc( jarc  );
+	    } else {
+		left.addarc( jarc  );
+	    }
+	}
+    }
+    if( param == 0 ) {
+	classify_headonleft_s( headonleft, intersections, left, value );
+	classify_tailonleft_s( tailonleft, intersections, left, value );
+	classify_headonright_s( headonright, intersections, right, value );
+	classify_tailonright_s( tailonright, intersections, right, value );
+    } else {
+	classify_headonleft_t( headonleft, intersections, left, value );
+	classify_tailonleft_t( tailonleft, intersections, left, value );
+	classify_headonright_t( headonright, intersections, right, value );
+	classify_tailonright_t( tailonright, intersections, right, value );
+    }
+}
+
+inline static void 
+vert_interp( TrimVertex *n, TrimVertex *l, TrimVertex *r, int p, REAL val )
+{
+    assert( val > l->param[p]);
+    assert( val < r->param[p]);
+
+    n->nuid = l->nuid;
+
+    n->param[p] = val;
+    if( l->param[1-p] != r->param[1-p]  ) {
+	REAL ratio = (val - l->param[p]) / (r->param[p] - l->param[p]);
+	n->param[1-p] = l->param[1-p] + 
+		        ratio * (r->param[1-p] - l->param[1-p]);
+    } else {
+	n->param[1-p] = l->param[1-p];
+    }
+}
+	
+int
+Subdivider::arc_split( Arc_ptr jarc, int param, REAL value, int dir )
+{
+    int		maxvertex = jarc->pwlArc->npts;
+    Arc_ptr	jarc1, jarc2, jarc3;
+    TrimVertex* v = jarc->pwlArc->pts;
+
+    int		loc[3];
+    switch( pwlarc_intersect( jarc->pwlArc, param, value, dir, loc ) ) {
+
+		// When the parameter value lands on a vertex, life is sweet
+    case INTERSECT_VERTEX: {
+	    jarc1 = new(arcpool) Arc( jarc, new( pwlarcpool) PwlArc( maxvertex-loc[1], &v[loc[1]] ) );
+	    jarc->pwlArc->npts = loc[1] + 1;
+	    jarc1->next = jarc->next;
+	    jarc1->next->prev = jarc1;
+	    jarc->next = jarc1;
+	    jarc1->prev = jarc;
+	    assert(jarc->check() != 0);
+	    return 2;
+	}
+
+		// When the parameter value intersects an edge, we have to
+		// interpolate a new vertex.  There are special cases
+		// if the new vertex is adjacent to one or both of the
+		// endpoints of the arc.
+    case INTERSECT_EDGE: {
+	    int i, j;
+	    if( dir == 0 ) {
+		i = loc[0];
+		j = loc[2];
+	    } else {
+		i = loc[2];
+		j = loc[0];
+	    }
+
+#ifndef NOTDEF
+	    // The split is between vertices at index j and i, in that
+	    // order (j < i)
+	    
+	    // JEB:  This code is my idea of how to do the split without
+	    // increasing the number of links.  I'm doing this so that
+	    // the is_rect routine can recognize rectangles created by
+	    // subdivision.  In exchange for simplifying the curve list,
+      	    // however, it costs in allocated space and vertex copies.
+	    
+	    TrimVertex *newjunk = trimvertexpool.get(maxvertex -i+1 /*-j*/);
+	    int k;
+	    for(k=0; k<maxvertex-i; k++)
+	      {
+		newjunk[k+1] = v[i+k];
+		newjunk[k+1].nuid = jarc->nuid;
+	      }
+	    
+	    TrimVertex *vcopy = trimvertexpool.get(maxvertex);
+	    for(k=0; k<maxvertex; k++)
+	      {
+		vcopy[k].param[0] = v[k].param[0];
+		vcopy[k].param[1] = v[k].param[1];
+	      }
+	    jarc->pwlArc->pts=vcopy;
+
+	    v[i].nuid = jarc->nuid;
+	    v[j].nuid = jarc->nuid;
+	    vert_interp( &newjunk[0], &v[loc[0]], &v[loc[2]], param, value );
+
+	    if( showingDegenerate() )
+		backend.triangle( &v[i], &newjunk[0], &v[j] );
+
+            vcopy[j+1].param[0]=newjunk[0].param[0];
+            vcopy[j+1].param[1]=newjunk[0].param[1];
+
+
+	    jarc1 = new(arcpool) Arc( jarc,
+			new(pwlarcpool) PwlArc(maxvertex-i+1 , newjunk ) );
+
+	    jarc->pwlArc->npts = j+2;
+	    jarc1->next = jarc->next;
+	    jarc1->next->prev = jarc1;
+	    jarc->next = jarc1;
+	    jarc1->prev = jarc;
+	    assert(jarc->check() != 0);
+
+	    return 2;
+#endif //not NOTDEF
+		// JEB: This is the original version:
+#ifdef NOTDEF
+
+	    TrimVertex *newjunk = trimvertexpool.get(3);
+	    v[i].nuid = jarc->nuid;
+	    v[j].nuid = jarc->nuid;
+	    newjunk[0] = v[j];
+	    newjunk[2] = v[i];
+	    vert_interp( &newjunk[1], &v[loc[0]], &v[loc[2]], param, value );
+
+	    if( showingDegenerate() )
+		backend.triangle( &newjunk[2], &newjunk[1], &newjunk[0] );
+
+		// New vertex adjacent to both endpoints
+	    if (maxvertex == 2) {
+		jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
+		jarc->pwlArc->npts = 2;
+		jarc->pwlArc->pts = newjunk;
+		jarc1->next = jarc->next;
+		jarc1->next->prev = jarc1;
+		jarc->next = jarc1;
+		jarc1->prev = jarc;
+		assert(jarc->check() != 0);
+
+		return 2;
+
+		// New vertex adjacent to ending point of arc
+	    } else if (maxvertex - j == 2) {
+		jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk ) );
+		jarc2 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
+		jarc->pwlArc->npts = maxvertex-1;
+		jarc2->next = jarc->next;
+		jarc2->next->prev = jarc2;
+		jarc->next = jarc1;
+		jarc1->prev = jarc;
+		jarc1->next = jarc2;
+		jarc2->prev = jarc1;
+		assert(jarc->check() != 0);
+		return 31;
+
+		// New vertex adjacent to starting point of arc
+	    } else if (i == 1) {
+		jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
+		jarc2 = new(arcpool) Arc( jarc, 
+			new(pwlarcpool) PwlArc( maxvertex-1, &jarc->pwlArc->pts[1] ) );
+		jarc->pwlArc->npts = 2;
+		jarc->pwlArc->pts = newjunk;
+		jarc2->next = jarc->next;
+		jarc2->next->prev = jarc2;
+		jarc->next = jarc1;
+		jarc1->prev = jarc;
+		jarc1->next = jarc2;
+		jarc2->prev = jarc1;
+		assert(jarc->check() != 0);
+		return 32;
+
+		// It's somewhere in the middle
+	    } else {
+		jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk ) );
+		jarc2 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
+		jarc3 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( maxvertex-i, v+i ) );
+		jarc->pwlArc->npts = j + 1;
+		jarc3->next = jarc->next;
+		jarc3->next->prev = jarc3;
+		jarc->next = jarc1;
+		jarc1->prev = jarc;
+		jarc1->next = jarc2;
+		jarc2->prev = jarc1;
+		jarc2->next = jarc3;
+		jarc3->prev = jarc2;
+		assert(jarc->check() != 0);
+		return 4;
+	    }
+#endif // NOTDEF
+	}
+	default:
+	return -1; //picked -1 since it's not used
+    }
+}
+
+/*----------------------------------------------------------------------------
+ * pwlarc_intersect -  find intersection of pwlArc and isoparametric line
+ *----------------------------------------------------------------------------
+ */
+
+static enum i_result
+pwlarc_intersect(
+    PwlArc *pwlArc,
+    int param,
+    REAL value,
+    int dir,
+    int loc[3] )
+{
+    assert( pwlArc->npts > 0 );
+
+    if( dir ) {
+	TrimVertex *v = pwlArc->pts;
+	int imin = 0; 
+	int imax = pwlArc->npts - 1;
+	assert( value > v[imin].param[param] );
+	assert( value < v[imax].param[param] );	
+	while( (imax - imin) > 1 ) {
+	    int imid = (imax + imin)/2;
+	    if( v[imid].param[param] > value )
+		imax = imid;
+	    else if( v[imid].param[param] < value )
+		imin = imid;
+	    else {
+		loc[1] = imid;
+		return INTERSECT_VERTEX;
+	    }
+	}
+	loc[0] = imin;
+	loc[2] = imax;
+	return INTERSECT_EDGE;
+    } else {
+	TrimVertex *v = pwlArc->pts;
+	int imax = 0; 
+	int imin = pwlArc->npts - 1;
+	assert( value > v[imin].param[param] );
+	assert( value < v[imax].param[param] );	
+	while( (imin - imax) > 1 ) {
+	    int imid = (imax + imin)/2;
+	    if( v[imid].param[param] > value )
+		imax = imid;
+	    else if( v[imid].param[param] < value )
+		imin = imid;
+	    else {
+		loc[1] = imid;
+		return INTERSECT_VERTEX;
+	    }
+	}
+	loc[0] = imin;
+	loc[2] = imax;
+	return INTERSECT_EDGE;
+    }
+}
+
+/*----------------------------------------------------------------------------
+ * arc_classify - determine which side of a line a jarc lies 
+ *----------------------------------------------------------------------------
+ */
+
+static int
+arc_classify( Arc_ptr jarc, int param, REAL value )
+{
+    REAL tdiff, hdiff;
+    if( param == 0 ) {
+	tdiff = jarc->tail()[0] - value;
+	hdiff = jarc->head()[0] - value;
+    } else {
+	tdiff = jarc->tail()[1] - value;
+	hdiff = jarc->head()[1] - value;
+    }
+
+    if( tdiff > 0.0 ) {
+	if( hdiff > 0.0 ) {
+	    return 0x11;
+	} else if( hdiff == 0.0 ) {
+	    return 0x12;
+	} else {
+	    return 0x10;
+	}
+    } else if( tdiff == 0.0 ) {
+	if( hdiff > 0.0 ) {
+	    return 0x21;
+	} else if( hdiff == 0.0 ) {
+	    return 0x22;
+	} else {
+	    return 0x20;
+	}
+    } else {
+	if( hdiff > 0.0 ) {
+	    return 0x01;
+	} else if( hdiff == 0.0 ) {
+	    return 0x02;
+	} else {
+	    return 0;
+	}
+    }
+}
+
+void
+Subdivider::classify_tailonleft_s( Bin& bin, Bin& in, Bin& out, REAL val )
+{
+    /* tail at left, head on line */
+    Arc_ptr j;
+
+    while( (j = bin.removearc()) != NULL ) {
+	assert( arc_classify( j, 0, val ) == 0x02 );
+	j->clearitail();
+
+	REAL diff = j->next->head()[0] - val;
+	if( diff > 0.0 ) {
+	    in.addarc( j );
+	} else if( diff < 0.0 ) {
+	    if( ccwTurn_sl( j, j->next ) )
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	} else {
+	    if( j->next->tail()[1] > j->next->head()[1] ) 
+		in.addarc(j);
+	    else
+		out.addarc(j);
+	}
+    }
+}
+
+void
+Subdivider::classify_tailonleft_t( Bin& bin, Bin& in, Bin& out, REAL val )
+{
+    /* tail at left, head on line */
+    Arc_ptr j;
+
+    while( (j = bin.removearc()) != NULL ) {
+	assert( arc_classify( j, 1, val ) == 0x02 );
+	j->clearitail();
+
+        REAL diff = j->next->head()[1] - val;
+	if( diff > 0.0 ) {
+	    in.addarc( j );
+	} else if( diff < 0.0 ) {
+	    if( ccwTurn_tl( j, j->next ) )
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	} else {
+	    if (j->next->tail()[0] > j->next->head()[0] )
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	}
+    }
+}
+
+void
+Subdivider::classify_headonleft_s( Bin& bin, Bin& in, Bin& out, REAL val )
+{
+    /* tail on line, head at left */
+    Arc_ptr j;
+
+    while( (j = bin.removearc()) != NULL ) {
+	assert( arc_classify( j, 0, val ) == 0x20 );
+
+	j->setitail();
+
+	REAL diff = j->prev->tail()[0] - val;
+	if( diff > 0.0 ) {
+	    out.addarc( j );
+	} else if( diff < 0.0 ) {
+	    if( ccwTurn_sl( j->prev, j ) )
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	} else {
+	    if( j->prev->tail()[1] > j->prev->head()[1] )
+		in.addarc( j );
+	    else
+		out.addarc( j );
+	}
+    }
+}
+
+void
+Subdivider::classify_headonleft_t( Bin& bin, Bin& in, Bin& out, REAL val )
+{
+    /* tail on line, head at left */
+    Arc_ptr j;
+
+    while( (j = bin.removearc()) != NULL ) {
+	assert( arc_classify( j, 1, val ) == 0x20 );
+	j->setitail();
+
+	REAL diff = j->prev->tail()[1] - val;
+	if( diff > 0.0 ) {
+	    out.addarc( j );
+	} else if( diff < 0.0 ) {
+	    if( ccwTurn_tl( j->prev, j ) )
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	} else {
+	    if( j->prev->tail()[0] > j->prev->head()[0] )
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	}
+    }
+}
+
+
+void
+Subdivider::classify_tailonright_s( Bin& bin, Bin& in, Bin& out, REAL val )
+{
+    /* tail at right, head on line */
+    Arc_ptr j;
+
+    while( (j = bin.removearc()) != NULL ) {
+	assert( arc_classify( j, 0, val ) == 0x12);
+	
+	j->clearitail();
+
+        REAL diff = j->next->head()[0] - val;
+	if( diff > 0.0 ) {
+	    if( ccwTurn_sr( j, j->next ) )
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	} else if( diff < 0.0 ) {
+	    in.addarc( j );
+	} else {
+	    if( j->next->tail()[1] > j->next->head()[1] ) 
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	}
+    }
+}
+
+void
+Subdivider::classify_tailonright_t( Bin& bin, Bin& in, Bin& out, REAL val )
+{
+    /* tail at right, head on line */
+    Arc_ptr j;
+
+    while( (j = bin.removearc()) != NULL ) {
+	assert( arc_classify( j, 1, val ) == 0x12);
+	
+	j->clearitail();
+
+	REAL diff =  j->next->head()[1] - val;
+	if( diff > 0.0 ) {
+	    if( ccwTurn_tr( j, j->next ) )
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	} else if( diff < 0.0 ) { 
+	    in.addarc( j );
+	} else {
+	    if( j->next->tail()[0] > j->next->head()[0] ) 
+		in.addarc( j );
+	    else
+		out.addarc( j );
+	}
+    }
+}
+
+void
+Subdivider::classify_headonright_s( Bin& bin, Bin& in, Bin& out, REAL val )
+{
+    /* tail on line, head at right */
+    Arc_ptr j;
+
+    while( (j = bin.removearc()) != NULL ) {
+	assert( arc_classify( j, 0, val ) == 0x21 );
+    
+	j->setitail();
+
+        REAL diff = j->prev->tail()[0] - val;
+	if( diff > 0.0 ) { 
+	    if( ccwTurn_sr( j->prev, j ) )
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	} else if( diff < 0.0 ) {
+	    out.addarc( j );
+	} else {
+	    if( j->prev->tail()[1] > j->prev->head()[1] )
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	}
+    }
+}
+
+void
+Subdivider::classify_headonright_t( Bin& bin, Bin& in, Bin& out, REAL val )
+{
+    /* tail on line, head at right */
+    Arc_ptr j;
+
+    while( (j = bin.removearc()) != NULL ) {
+	assert( arc_classify( j, 1, val ) == 0x21 );
+    
+	j->setitail();
+
+        REAL diff = j->prev->tail()[1] - val;
+	if( diff > 0.0 ) { 
+	    if( ccwTurn_tr( j->prev, j ) )
+		out.addarc( j );
+	    else
+		in.addarc( j );
+	} else if( diff < 0.0 ) {
+	    out.addarc( j );
+	} else {
+	    if( j->prev->tail()[0] > j->prev->head()[0] )
+		in.addarc( j );
+	    else
+		out.addarc( j );
+	}
+    }
+}
+