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Diffstat (limited to 'libtess/tessmono.c')
| -rw-r--r-- | libtess/tessmono.c | 208 |
1 files changed, 0 insertions, 208 deletions
diff --git a/libtess/tessmono.c b/libtess/tessmono.c deleted file mode 100644 index 2789814..0000000 --- a/libtess/tessmono.c +++ /dev/null @@ -1,208 +0,0 @@ -/* -** 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. -** -*/ -/* -** Author: Eric Veach, July 1994. -** -** $Date$ $Revision$ -** $Header$ -*/ - -#include "gluos.h" -#include <stdlib.h> -#include "geom.h" -#include "mesh.h" -#include "tessmono.h" -#include <assert.h> - -#define AddWinding(eDst,eSrc) (eDst->winding += eSrc->winding, \ - eDst->Sym->winding += eSrc->Sym->winding) - -/* __gl_meshTessellateMonoRegion( face ) tessellates a monotone region - * (what else would it do??) The region must consist of a single - * loop of half-edges (see mesh.h) oriented CCW. "Monotone" in this - * case means that any vertical line intersects the interior of the - * region in a single interval. - * - * Tessellation consists of adding interior edges (actually pairs of - * half-edges), to split the region into non-overlapping triangles. - * - * The basic idea is explained in Preparata and Shamos (which I don''t - * have handy right now), although their implementation is more - * complicated than this one. The are two edge chains, an upper chain - * and a lower chain. We process all vertices from both chains in order, - * from right to left. - * - * The algorithm ensures that the following invariant holds after each - * vertex is processed: the untessellated region consists of two - * chains, where one chain (say the upper) is a single edge, and - * the other chain is concave. The left vertex of the single edge - * is always to the left of all vertices in the concave chain. - * - * Each step consists of adding the rightmost unprocessed vertex to one - * of the two chains, and forming a fan of triangles from the rightmost - * of two chain endpoints. Determining whether we can add each triangle - * to the fan is a simple orientation test. By making the fan as large - * as possible, we restore the invariant (check it yourself). - */ -int __gl_meshTessellateMonoRegion( GLUface *face ) -{ - GLUhalfEdge *up, *lo; - - /* All edges are oriented CCW around the boundary of the region. - * First, find the half-edge whose origin vertex is rightmost. - * Since the sweep goes from left to right, face->anEdge should - * be close to the edge we want. - */ - up = face->anEdge; - assert( up->Lnext != up && up->Lnext->Lnext != up ); - - for( ; VertLeq( up->Dst, up->Org ); up = up->Lprev ) - ; - for( ; VertLeq( up->Org, up->Dst ); up = up->Lnext ) - ; - lo = up->Lprev; - - while( up->Lnext != lo ) { - if( VertLeq( up->Dst, lo->Org )) { - /* up->Dst is on the left. It is safe to form triangles from lo->Org. - * The EdgeGoesLeft test guarantees progress even when some triangles - * are CW, given that the upper and lower chains are truly monotone. - */ - while( lo->Lnext != up && (EdgeGoesLeft( lo->Lnext ) - || EdgeSign( lo->Org, lo->Dst, lo->Lnext->Dst ) <= 0 )) { - GLUhalfEdge *tempHalfEdge= __gl_meshConnect( lo->Lnext, lo ); - if (tempHalfEdge == NULL) return 0; - lo = tempHalfEdge->Sym; - } - lo = lo->Lprev; - } else { - /* lo->Org is on the left. We can make CCW triangles from up->Dst. */ - while( lo->Lnext != up && (EdgeGoesRight( up->Lprev ) - || EdgeSign( up->Dst, up->Org, up->Lprev->Org ) >= 0 )) { - GLUhalfEdge *tempHalfEdge= __gl_meshConnect( up, up->Lprev ); - if (tempHalfEdge == NULL) return 0; - up = tempHalfEdge->Sym; - } - up = up->Lnext; - } - } - - /* Now lo->Org == up->Dst == the leftmost vertex. The remaining region - * can be tessellated in a fan from this leftmost vertex. - */ - assert( lo->Lnext != up ); - while( lo->Lnext->Lnext != up ) { - GLUhalfEdge *tempHalfEdge= __gl_meshConnect( lo->Lnext, lo ); - if (tempHalfEdge == NULL) return 0; - lo = tempHalfEdge->Sym; - } - - return 1; -} - - -/* __gl_meshTessellateInterior( mesh ) tessellates each region of - * the mesh which is marked "inside" the polygon. Each such region - * must be monotone. - */ -int __gl_meshTessellateInterior( GLUmesh *mesh ) -{ - GLUface *f, *next; - - /*LINTED*/ - for( f = mesh->fHead.next; f != &mesh->fHead; f = next ) { - /* Make sure we don''t try to tessellate the new triangles. */ - next = f->next; - if( f->inside ) { - if ( !__gl_meshTessellateMonoRegion( f ) ) return 0; - } - } - - return 1; -} - - -/* __gl_meshDiscardExterior( mesh ) zaps (ie. sets to NULL) all faces - * which are not marked "inside" the polygon. Since further mesh operations - * on NULL faces are not allowed, the main purpose is to clean up the - * mesh so that exterior loops are not represented in the data structure. - */ -void __gl_meshDiscardExterior( GLUmesh *mesh ) -{ - GLUface *f, *next; - - /*LINTED*/ - for( f = mesh->fHead.next; f != &mesh->fHead; f = next ) { - /* Since f will be destroyed, save its next pointer. */ - next = f->next; - if( ! f->inside ) { - __gl_meshZapFace( f ); - } - } -} - -#define MARKED_FOR_DELETION 0x7fffffff - -/* __gl_meshSetWindingNumber( mesh, value, keepOnlyBoundary ) resets the - * winding numbers on all edges so that regions marked "inside" the - * polygon have a winding number of "value", and regions outside - * have a winding number of 0. - * - * If keepOnlyBoundary is TRUE, it also deletes all edges which do not - * separate an interior region from an exterior one. - */ -int __gl_meshSetWindingNumber( GLUmesh *mesh, int value, - GLboolean keepOnlyBoundary ) -{ - GLUhalfEdge *e, *eNext; - - for( e = mesh->eHead.next; e != &mesh->eHead; e = eNext ) { - eNext = e->next; - if( e->Rface->inside != e->Lface->inside ) { - - /* This is a boundary edge (one side is interior, one is exterior). */ - e->winding = (e->Lface->inside) ? value : -value; - } else { - - /* Both regions are interior, or both are exterior. */ - if( ! keepOnlyBoundary ) { - e->winding = 0; - } else { - if ( !__gl_meshDelete( e ) ) return 0; - } - } - } - return 1; -} |