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      1 /*
      2  * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
      3  * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
      4  *
      5  * Permission is hereby granted, free of charge, to any person obtaining a
      6  * copy of this software and associated documentation files (the "Software"),
      7  * to deal in the Software without restriction, including without limitation
      8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      9  * and/or sell copies of the Software, and to permit persons to whom the
     10  * Software is furnished to do so, subject to the following conditions:
     11  *
     12  * The above copyright notice including the dates of first publication and
     13  * either this permission notice or a reference to
     14  * http://oss.sgi.com/projects/FreeB/
     15  * shall be included in all copies or substantial portions of the Software.
     16  *
     17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
     20  * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
     21  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
     22  * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     23  * SOFTWARE.
     24  *
     25  * Except as contained in this notice, the name of Silicon Graphics, Inc.
     26  * shall not be used in advertising or otherwise to promote the sale, use or
     27  * other dealings in this Software without prior written authorization from
     28  * Silicon Graphics, Inc.
     29  */
     30 /*
     31 ** Author: Eric Veach, July 1994.
     32 **
     33 */
     34 
     35 #ifndef __geom_h_
     36 #define __geom_h_
     37 
     38 #include "mesh.h"
     39 
     40 #ifdef NO_BRANCH_CONDITIONS
     41 /* MIPS architecture has special instructions to evaluate boolean
     42  * conditions -- more efficient than branching, IF you can get the
     43  * compiler to generate the right instructions (SGI compiler doesn't)
     44  */
     45 #define VertEq(u,v)	(((u)->s == (v)->s) & ((u)->t == (v)->t))
     46 #define VertLeq(u,v)	(((u)->s < (v)->s) | \
     47                          ((u)->s == (v)->s & (u)->t <= (v)->t))
     48 #else
     49 #define VertEq(u,v)	((u)->s == (v)->s && (u)->t == (v)->t)
     50 #define VertLeq(u,v)	(((u)->s < (v)->s) || \
     51                          ((u)->s == (v)->s && (u)->t <= (v)->t))
     52 #endif
     53 
     54 #define EdgeEval(u,v,w) __gl_edgeEval(u,v,w)
     55 #define EdgeSign(u,v,w) __gl_edgeSign(u,v,w)
     56 
     57 /* Versions of VertLeq, EdgeSign, EdgeEval with s and t transposed. */
     58 
     59 #define TransLeq(u,v)	(((u)->t < (v)->t) || \
     60                          ((u)->t == (v)->t && (u)->s <= (v)->s))
     61 #define TransEval(u,v,w)	__gl_transEval(u,v,w)
     62 #define TransSign(u,v,w)	__gl_transSign(u,v,w)
     63 
     64 
     65 #define EdgeGoesLeft(e) 	VertLeq( (e)->Dst, (e)->Org )
     66 #define EdgeGoesRight(e)	VertLeq( (e)->Org, (e)->Dst )
     67 
     68 #undef	ABS
     69 #define ABS(x)	((x) < 0 ? -(x) : (x))
     70 #define VertL1dist(u,v) (ABS(u->s - v->s) + ABS(u->t - v->t))
     71 
     72 #define VertCCW(u,v,w)	__gl_vertCCW(u,v,w)
     73 
     74 int		__gl_vertLeq( GLUvertex *u, GLUvertex *v );
     75 GLdouble	__gl_edgeEval( GLUvertex *u, GLUvertex *v, GLUvertex *w );
     76 GLdouble	__gl_edgeSign( GLUvertex *u, GLUvertex *v, GLUvertex *w );
     77 GLdouble	__gl_transEval( GLUvertex *u, GLUvertex *v, GLUvertex *w );
     78 GLdouble	__gl_transSign( GLUvertex *u, GLUvertex *v, GLUvertex *w );
     79 int		__gl_vertCCW( GLUvertex *u, GLUvertex *v, GLUvertex *w );
     80 void		__gl_edgeIntersect( GLUvertex *o1, GLUvertex *d1,
     81 				    GLUvertex *o2, GLUvertex *d2,
     82 				    GLUvertex *v );
     83 
     84 #endif
     85