Merge pull request #1949 from Areloch/getSignedAngleFunc

Adds the getSignedAngleBetweenVectors function

Engine/source/math/mConsoleFunctions.cpp

@@ -373,3 +373,20 @@ DefineConsoleFunction( mGetAngleBetweenVectors, F32, (VectorF vecA, VectorF vecB
 {
    return MathUtils::getAngleBetweenVectors(vecA, vecB);
 }
+
+DefineConsoleFunction(mGetSignedAngleBetweenVectors, F32, (VectorF vecA, VectorF vecB, VectorF norm), (VectorF::Zero, VectorF::Zero, VectorF::Zero),
+   "Returns signed angle between two vectors, using a normal for orientation.\n"
+   "@param vecA First input vector."
+   "@param vecB Second input vector."
+   "@param norm Normal/Cross Product vector."
+   "@returns Angle between both vectors in radians."
+   "@ingroup Math")
+{
+   if (vecA.isZero() || vecB.isZero() || norm.isZero())
+   {
+      Con::errorf("mGetSignedAngleBetweenVectors - Error! Requires all 3 vectors used to be non-zero!");
+      return 0;
+   }
+
+   return MathUtils::getSignedAngleBetweenVectors(vecA, vecB, norm);
+}

Engine/source/math/mathUtils.cpp

@@ -371,6 +371,18 @@ F32 getAngleBetweenVectors(VectorF vecA, VectorF vecB)
    return angle;
 }
 
+F32 getSignedAngleBetweenVectors(VectorF vecA, VectorF vecB, VectorF norm)
+{
+   // angle in 0-180
+   F32 angle = getAngleBetweenVectors(vecA, vecB);
+   F32 sign = mSign(mDot(norm, mCross(vecA, vecB)));
+
+   // angle in -179-180
+   F32 signed_angle = angle * sign;
+
+   return signed_angle;
+}
+
 //-----------------------------------------------------------------------------
 
 void transformBoundingBox(const Box3F &sbox, const MatrixF &mat, const Point3F scale, Box3F &dbox)

Engine/source/math/mathUtils.h

@@ -161,6 +161,11 @@ namespace MathUtils
    ///
    F32 getAngleBetweenVectors(VectorF vecA, VectorF vecB);
 
+   /// Returns the angle between two given vectors, utilizing a normal vector to discertain the angle's sign
+   /// 
+   /// Angles is in RADIANS
+   ///
+   F32 getSignedAngleBetweenVectors(VectorF vecA, VectorF vecB, VectorF norm);
 
    /// Simple reflection equation - pass in a vector and a normal to reflect off of
    inline Point3F reflect( Point3F &inVec, Point3F &norm )