1 files changed, 105 insertions, 0 deletions
diff --git a/src/base/Triangle.cpp b/src/base/Triangle.cpp
new file mode 100644
index 0000000..7efe9f7
--- /dev/null
+++ b/src/base/Triangle.cpp
@@ -0,0 +1,105 @@
+//
+//  libavg - Media Playback Engine.
+//  Copyright (C) 2003-2014 Ulrich von Zadow
+//
+//  This library is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU Lesser General Public
+//  License as published by the Free Software Foundation; either
+//  version 2 of the License, or (at your option) any later version.
+//
+//  This library is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//  Lesser General Public License for more details.
+//
+//  You should have received a copy of the GNU Lesser General Public
+//  License along with this library; if not, write to the Free Software
+//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+//
+//  Current versions can be found at www.libavg.de
+//
+
+#include "Triangle.h"
+
+#include "GLMHelper.h"
+
+#include <math.h>
+
+namespace avg {
+
+Triangle::Triangle(const glm::vec2& P0, const glm::vec2& P1, const glm::vec2& P2)
+    : p0(P0),
+      p1(P1),
+      p2(P2)
+{
+}
+
+Triangle::Triangle()
+{
+}
+
+bool Triangle::operator ==(const Triangle & tri) const
+{
+    return (p0 == tri.p0 && p1 == tri.p1 &&  p2 == tri.p2);
+}
+
+bool Triangle::isInside(const glm::vec2& pt) const
+{
+/* Slower func that only works for cw triangles.
+
+    glm::vec2 a = p2-p1;
+    glm::vec2 bp = pt-p1;
+    float aCROSSbp = a.x*bp.y - a.y*bp.x;
+    if (aCROSSbp < 0.0) {
+        return false;
+    }
+    
+    glm::vec2 b = p0-p2;
+    glm::vec2 cp = pt-p2;
+    float bCROSScp = b.x*cp.y - b.y*cp.x;
+    if (bCROSScp < 0.0) {
+        return false;
+    }
+
+    glm::vec2 c = p1-p0;
+    glm::vec2 ap = pt-p0;
+    float cCROSSap = c.x*ap.y - c.y*ap.x;
+    return cCROSSap >= 0.0;
+*/
+    glm::vec2 v0 = p2 - p0;
+    glm::vec2 v1 = p1 - p0;
+    glm::vec2 v2 = pt - p0;
+
+    float dot00 = glm::dot(v0, v0);
+    float dot01 = glm::dot(v0, v1);
+    float dot02 = glm::dot(v0, v2);
+    float dot11 = glm::dot(v1, v1);
+    float dot12 = glm::dot(v1, v2);
+
+    float invDenom = 1 / (dot00 * dot11 - dot01 * dot01);
+    float u = (dot11 * dot02 - dot01 * dot12) * invDenom;
+    float v = (dot00 * dot12 - dot01 * dot02) * invDenom;
+
+    return (u > 0) && (v > 0) && (u + v < 1);
+
+}
+
+float Triangle::getArea() const
+{
+    return fabs((((p1.x-p0.x)*(p2.y-p0.y)) - ((p1.y-p0.y)*(p2.x-p0.x)))/2);
+}
+
+bool Triangle::isClockwise() const
+{
+    return ((p1.x-p0.x)*(p2.y-p0.y)) - ((p1.y-p0.y)*(p2.x-p0.x)) < 0;
+}
+
+std::ostream& operator<<(std::ostream& os, const Triangle& tri)
+{
+    os << "(" << tri.p0 << "," << tri.p1 << "," << tri.p2 << ")";
+    return os;
+}
+
+
+}
+