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      1 /*
      2 ** License Applicability. Except to the extent portions of this file are
      3 ** made subject to an alternative license as permitted in the SGI Free
      4 ** Software License B, Version 1.1 (the "License"), the contents of this
      5 ** file are subject only to the provisions of the License. You may not use
      6 ** this file except in compliance with the License. You may obtain a copy
      7 ** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
      8 ** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
      9 **
     10 ** http://oss.sgi.com/projects/FreeB
     11 **
     12 ** Note that, as provided in the License, the Software is distributed on an
     13 ** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
     14 ** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
     15 ** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
     16 ** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
     17 **
     18 ** Original Code. The Original Code is: OpenGL Sample Implementation,
     19 ** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
     20 ** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
     21 ** Copyright in any portions created by third parties is as indicated
     22 ** elsewhere herein. All Rights Reserved.
     23 **
     24 ** Additional Notice Provisions: The application programming interfaces
     25 ** established by SGI in conjunction with the Original Code are The
     26 ** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
     27 ** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
     28 ** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
     29 ** Window System(R) (Version 1.3), released October 19, 1998. This software
     30 ** was created using the OpenGL(R) version 1.2.1 Sample Implementation
     31 ** published by SGI, but has not been independently verified as being
     32 ** compliant with the OpenGL(R) version 1.2.1 Specification.
     33 **
     34 */
     35 /*
     36 ** Author: Eric Veach, July 1994.
     37 **
     38 ** $Date$ $Revision$
     39 ** $Header: //depot/main/gfx/lib/glu/libtess/geom.h#5 $
     40 */
     41 
     42 #ifndef __geom_h_
     43 #define __geom_h_
     44 
     45 #include "mesh.h"
     46 
     47 #ifdef NO_BRANCH_CONDITIONS
     48 /* MIPS architecture has special instructions to evaluate boolean
     49  * conditions -- more efficient than branching, IF you can get the
     50  * compiler to generate the right instructions (SGI compiler doesn't)
     51  */
     52 #define VertEq(u,v)	(((u)->s == (v)->s) & ((u)->t == (v)->t))
     53 #define VertLeq(u,v)	(((u)->s < (v)->s) | \
     54                          ((u)->s == (v)->s & (u)->t <= (v)->t))
     55 #else
     56 #define VertEq(u,v)	((u)->s == (v)->s && (u)->t == (v)->t)
     57 #define VertLeq(u,v)	(((u)->s < (v)->s) || \
     58                          ((u)->s == (v)->s && (u)->t <= (v)->t))
     59 #endif
     60 
     61 #define EdgeEval(u,v,w)	__gl_edgeEval(u,v,w)
     62 #define EdgeSign(u,v,w)	__gl_edgeSign(u,v,w)
     63 
     64 /* Versions of VertLeq, EdgeSign, EdgeEval with s and t transposed. */
     65 
     66 #define TransLeq(u,v)	(((u)->t < (v)->t) || \
     67                          ((u)->t == (v)->t && (u)->s <= (v)->s))
     68 #define TransEval(u,v,w)	__gl_transEval(u,v,w)
     69 #define TransSign(u,v,w)	__gl_transSign(u,v,w)
     70 
     71 
     72 #define EdgeGoesLeft(e)		VertLeq( (e)->Dst, (e)->Org )
     73 #define EdgeGoesRight(e)	VertLeq( (e)->Org, (e)->Dst )
     74 
     75 #define ABS(x)	((x) < 0 ? -(x) : (x))
     76 #define VertL1dist(u,v)	(ABS(u->s - v->s) + ABS(u->t - v->t))
     77 
     78 #define VertCCW(u,v,w)	__gl_vertCCW(u,v,w)
     79 
     80 int		__gl_vertLeq( GLUvertex *u, GLUvertex *v );
     81 GLdouble	__gl_edgeEval( GLUvertex *u, GLUvertex *v, GLUvertex *w );
     82 GLdouble	__gl_edgeSign( GLUvertex *u, GLUvertex *v, GLUvertex *w );
     83 GLdouble	__gl_transEval( GLUvertex *u, GLUvertex *v, GLUvertex *w );
     84 GLdouble	__gl_transSign( GLUvertex *u, GLUvertex *v, GLUvertex *w );
     85 int		__gl_vertCCW( GLUvertex *u, GLUvertex *v, GLUvertex *w );
     86 void		__gl_edgeIntersect( GLUvertex *o1, GLUvertex *d1,
     87 				    GLUvertex *o2, GLUvertex *d2,
     88 				    GLUvertex *v );
     89 
     90 #endif
     91