From 19bc1e6313e889f89e44ee8d9429c84224f41e4f Mon Sep 17 00:00:00 2001
From: frohlich <frohlich>
Date: Fri, 27 Feb 2009 18:52:53 +0000
Subject: [PATCH] Initialize random number for the tests. Define the triangles
 center by the weighted sum of the vertices.

Modified Files:
	SGGeometryTest.cxx SGTriangle.hxx
---
 simgear/math/SGGeometryTest.cxx | 8 ++++++--
 simgear/math/SGTriangle.hxx     | 8 +-------
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/simgear/math/SGGeometryTest.cxx b/simgear/math/SGGeometryTest.cxx
index cd2383ee..432e87b6 100644
--- a/simgear/math/SGGeometryTest.cxx
+++ b/simgear/math/SGGeometryTest.cxx
@@ -44,6 +44,8 @@ TriangleLineIntersectionTest(void)
     
     SGTriangle<T> tri(v0, v1, v2);
 
+    T triangleEps = 100*SGLimits<T>::epsilon();
+
     // generate random coeficients
     T u = 4*sg_random() - 2;
     T v = 4*sg_random() - 2;
@@ -59,7 +61,7 @@ TriangleLineIntersectionTest(void)
     
     if (intersects(isectres, tri, lineSegment)) {
       if (0 <= u && 0 <= v && u+v <= 1 && 0 <= t && t <= 1) {
-        if (!equivalent(isectres, isectpt)) {
+        if (!equivalent(isectres, isectpt, triangleEps)) {
           std::cout << "Failed line segment intersection test #" << i
                     << ": not equivalent!\nu = "
                     << u << ", v = " << v << ", t = " << t
@@ -87,7 +89,7 @@ TriangleLineIntersectionTest(void)
     ray.set(isectpt - t*dir, dir);
     if (intersects(isectres, tri, ray)) {
       if (0 <= u && 0 <= v && u+v <= 1 && 0 <= t) {
-        if (!equivalent(isectres, isectpt)) {
+        if (!equivalent(isectres, isectpt, triangleEps)) {
           std::cout << "Failed ray intersection test #" << i
                     << ": not equivalent!\nu = "
                     << u << ", v = " << v << ", t = " << t
@@ -422,6 +424,8 @@ main(void)
             << "Some of these tests can fail due to roundoff problems...\n"
             << "Dont worry if only a few of them fail..." << std::endl;
 
+  sg_srandom(17);
+
   if (!TriangleLineIntersectionTest<float>())
     return EXIT_FAILURE;
   if (!TriangleLineIntersectionTest<double>())
diff --git a/simgear/math/SGTriangle.hxx b/simgear/math/SGTriangle.hxx
index 2cba610a..bc395ab9 100644
--- a/simgear/math/SGTriangle.hxx
+++ b/simgear/math/SGTriangle.hxx
@@ -42,13 +42,7 @@ public:
   }
 
   SGVec3<T> getCenter() const
-  {
-    SGBox<T> box;
-    box.expandBy(_v0);
-    box.expandBy(_v0 + _d[0]);
-    box.expandBy(_v0 + _d[1]);
-    return box.getCenter();
-  }
+  { return _v0 + T(1)/T(3)*(_d[0] + _d[1]); }
 
   // note that the index is unchecked
   SGVec3<T> getVertex(unsigned i) const
-- 
2.39.5