X-Git-Url: http://gitweb.pgornicz.com/gitweb.cgi?a=blobdiff_plain;f=src%2Fmathw.cpp;h=2b71dece6336c80fc9ab372f1cdfc3327488c838;hb=bcd46b8f4ee0d9b5ed6d983793f962ff66efa3aa;hp=430a601be26c274111906eb574a30c4254edf6b0;hpb=27b748208e91c2e802cbc2b8f7ab3620adaf6cb6;p=physics.git

diff --git a/src/mathw.cpp b/src/mathw.cpp
index 430a601..2b71dec 100644
--- a/src/mathw.cpp
+++ b/src/mathw.cpp
@@ -1,9 +1,21 @@
-#include "mathw.h"
-
-
-/// ***** Private Varibles *****
+/*
+ *  Copyright (C) 2008 Patrik Gornicz, Gornicz_P (at) hotmail (dot) com.
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
 
-const float PI = 3.141592653;
+#include "mathw.h"
 
 
 /// ***** Public Methods *****
@@ -13,16 +25,45 @@ int mod(int x, int y)
   return x % y + (x < 0 ? y : 0);
 }
 
-/// Vector2 Math
+// Vector2 Math
+
+Vector2 vectorToLine
+(
+  const Vector2& vec,
+  float x1,
+  float y1,
+  float x2,
+  float y2
+)
+{
+    float lineSize = (float) sqrt((x1 - x2) * (x1 - x2)
+                                + (y1 - y2) * (y1 - y2));
+    if (lineSize == 0)
+        return Vector2(x1 - vec.m_fX, y1 - vec.m_fY);
+
+    float u = ((vec.m_fX - x1) * (x2 - x1)
+             + (vec.m_fY - y1) * (y2 - y1)) / (lineSize * lineSize);
+
+    if (u < 0)
+        return Vector2(x1 - vec.m_fX, y1 - vec.m_fY);
+    else if (u > 1)
+        return Vector2(x2 - vec.m_fX, y2 - vec.m_fY);
+    else
+    {
+        float ix = x1 + u * (x2 - x1);
+        float iy = y1 + u * (y2 - y1);
+        return Vector2(ix - vec.m_fX, iy - vec.m_fY);
+    }
+}
 
 Vector2 perp(const Vector2& vec)
 {
-  return Vector2(-vec.y, vec.x);
+  return Vector2(-vec.m_fY, vec.m_fX);
 }
 
 float dot(const Vector2& vec1, const Vector2& vec2)
 {
-  return vec1.x * vec2.x + vec1.y * vec2.y;
+  return vec1.m_fX * vec2.m_fX + vec1.m_fY * vec2.m_fY;
 }
 
 //TODO float Vector2::projectionCoeff(const Vector2* vec) const;