From f4092abdf94af6a99aff944d6264bc1284e8bdd4 Mon Sep 17 00:00:00 2001 From: Reinhard Tartler Date: Mon, 10 Oct 2011 17:43:39 +0200 Subject: Imported nx-X11-3.1.0-1.tar.gz Summary: Imported nx-X11-3.1.0-1.tar.gz Keywords: Imported nx-X11-3.1.0-1.tar.gz into Git repository --- .../main/gfx/lib/glu/libnurbs/nurbtess/polyUtil.cc | 92 ++++++++++++++++++++++ 1 file changed, 92 insertions(+) create mode 100644 nx-X11/extras/ogl-sample/main/gfx/lib/glu/libnurbs/nurbtess/polyUtil.cc (limited to 'nx-X11/extras/ogl-sample/main/gfx/lib/glu/libnurbs/nurbtess/polyUtil.cc') diff --git a/nx-X11/extras/ogl-sample/main/gfx/lib/glu/libnurbs/nurbtess/polyUtil.cc b/nx-X11/extras/ogl-sample/main/gfx/lib/glu/libnurbs/nurbtess/polyUtil.cc new file mode 100644 index 000000000..2777321a7 --- /dev/null +++ b/nx-X11/extras/ogl-sample/main/gfx/lib/glu/libnurbs/nurbtess/polyUtil.cc @@ -0,0 +1,92 @@ +/* +** 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. +** +** $Date: 2004/03/14 08:29:11 $ $Revision: 1.1.1.4 $ +*/ +/* +** $Header: /cvs/xorg/xc/extras/ogl-sample/main/gfx/lib/glu/libnurbs/nurbtess/polyUtil.cc,v 1.1.1.4 2004/03/14 08:29:11 eich Exp $ +*/ + +#include +#include + +#include "polyUtil.h" + +Real area(Real A[2], Real B[2], Real C[2]) +{ + Real Bx, By, Cx, Cy; + Bx = B[0] - A[0]; + By = B[1] - A[1]; + Cx = C[0] - A[0]; + Cy = C[1] - A[1]; + return Bx*Cy - Cx*By; + +/* return (B[0]-A[0])*(C[1]-A[1]) - (C[0]-A[0])*(B[1]-A[1]);*/ +} + +/*given a directed line A->B, and a point P, + *determine whether P is to the left of AB. + *the line A->B (imagine it has beedn extended both + *end to the infinity) divides the plan into two + *half planes. When we walk from A to B, one + *half is to the left and the other half is to the right. + *return 1 if P is to the left. + *if P is on AB, 0 is returned. + */ +Int pointLeftLine(Real A[2], Real B[2], Real P[2]) +{ + if(area(A, B, P) >0) return 1; + else return 0; +} + +/*given two directed line: A -> B -> C, and another point P. + *determine whether P is to the left hand side of A->B->C. + *Think of BA and BC extended as two rays. So that the plane is + * divided into two parts. One part is to the left we walk from A + *to B and to C, the other part is to the right. + * In order for P to be the left, P must be either to the left + *of + */ +Int pointLeft2Lines(Real A[2], Real B[2], Real C[2], Real P[2]) +{ + Int C_left_AB = (area(A, B, C)>0); + Int P_left_AB = (area(A, B, P)>0); + Int P_left_BC = (area(B, C, P)>0); + + if(C_left_AB) + { + return (P_left_AB && P_left_BC); + } + else + return (P_left_AB || P_left_BC); +} -- cgit v1.2.3