Added MesaLib-7.6

1 files changed, 90 insertions, 0 deletions

diff --git a/mesalib/src/glu/sgi/libnurbs/nurbtess/polyUtil.cc b/mesalib/src/glu/sgi/libnurbs/nurbtess/polyUtil.cc
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index 000000000..f9a27f402
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+++ b/mesalib/src/glu/sgi/libnurbs/nurbtess/polyUtil.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.
+**
+*/
+/*
+*/
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#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);
+}