From 8af36d5f6590b4f49acc288f9113cca4df3c99a0 Mon Sep 17 00:00:00 2001
From: Tom Brazier <tom_github@firstsolo.net>
Date: Mon, 5 Jun 2023 15:26:24 +0100
Subject: Changed hamiltons tools to use pass by reference

---
 compat/hamilton-tools.cpp | 18 +++++++++---------
 compat/hamilton-tools.h   | 10 +++++-----
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/compat/hamilton-tools.cpp b/compat/hamilton-tools.cpp
index e18082a8..dfbb4630 100644
--- a/compat/hamilton-tools.cpp
+++ b/compat/hamilton-tools.cpp
@@ -1,19 +1,19 @@
 #include "hamilton-tools.h"
 #include <cmath>
 
-double VectorLength(const tVector v)
+double VectorLength(const tVector& v)
 {
     return(sqrt(v.v[0]*v.v[0] + v.v[1]*v.v[1] + v.v[2]*v.v[2]));
 }
 		
 double sqr(const double v) { return(v*v); }
 
-double VectorDistance(const double v1[], const tVector v2)
+double VectorDistance(const double v1[], const tVector& v2)
 {
     return(sqrt(sqr(v2.v[0]-v1[0])+sqr(v2.v[1]-v1[1])+sqr(v2.v[2]-v1[2])));
 }
 
-tVector Lerp(const tVector s, const double d[], const double alpha)
+tVector Lerp(const tVector& s, const double d[], const double alpha)
 {
     tVector V;
     V.v[0] = s.v[0] + (d[0] - s.v[0]) * alpha;
@@ -22,7 +22,7 @@ tVector Lerp(const tVector s, const double d[], const double alpha)
     return(V);
 }	
 
-tQuat QuatFromAngleAxe(const double angle, const tVector axe)
+tQuat QuatFromAngleAxe(const double angle, const tVector& axe)
 {
     double a = TO_RAD * 0.5 * angle;
     double d = sin(a) / VectorLength(axe);
@@ -35,7 +35,7 @@ tQuat QuatFromAngleAxe(const double angle, const tVector axe)
             );
 }
 		
-tQuat QuatMultiply(const tQuat qL, const tQuat qR)
+tQuat QuatMultiply(const tQuat& qL, const tQuat& qR)
 {
     tQuat Q;
     Q.x = qL.w*qR.x + qL.x*qR.w + qL.y*qR.z - qL.z*qR.y;
@@ -45,7 +45,7 @@ tQuat QuatMultiply(const tQuat qL, const tQuat qR)
     return(Q);
 }
 
-double AngleBetween(const tQuat S, const tQuat D)
+double AngleBetween(const tQuat& S, const tQuat& D)
 {
     return( TO_DEG * 2*acos(fabs(S.x*D.x + S.y*D.y + S.z*D.z + S.w*D.w)) );
 }
@@ -61,7 +61,7 @@ tQuat QuatFromYPR(const double YPR[])
     return(QuatMultiply(Qy, Q));
 }
 
-void Normalize(tQuat Q)
+void Normalize(tQuat& Q)
 {
     double m = sqrt(Q.x*Q.x + Q.y*Q.y + Q.z*Q.z + Q.w*Q.w);
     if (m > EPSILON)
@@ -75,7 +75,7 @@ void Normalize(tQuat Q)
     else Q = tQuat(0, 0, 0, 1);
 }
 
-tQuat Slerp(const tQuat S, const tQuat D, const double alpha)
+tQuat Slerp(const tQuat& S, const tQuat& D, const double alpha)
 {
     // calc cosine of half angle
     double cosin = S.x*D.x + S.y*D.y + S.z*D.z + S.w*D.w;
@@ -117,7 +117,7 @@ tQuat Slerp(const tQuat S, const tQuat D, const double alpha)
     return( Q );
 }
 
-void QuatToYPR(const tQuat Q, double YPR[])
+void QuatToYPR(const tQuat& Q, double YPR[])
 {
     const double xx = Q.x * Q.x;
     const double xy = Q.x * Q.y;
diff --git a/compat/hamilton-tools.h b/compat/hamilton-tools.h
index 6bcd7b5d..73bc882c 100644
--- a/compat/hamilton-tools.h
+++ b/compat/hamilton-tools.h
@@ -21,9 +21,9 @@ struct tQuat
         {x = X; y = Y; z = Z; w = W;}
 };
 
-double  OTR_COMPAT_EXPORT VectorDistance(const double v1[], const tVector v2);
-tVector OTR_COMPAT_EXPORT Lerp          (const tVector s, const double d[], const double alpha);
+double  OTR_COMPAT_EXPORT VectorDistance(const double v1[], const tVector& v2);
+tVector OTR_COMPAT_EXPORT Lerp          (const tVector& s, const double d[], const double alpha);
 tQuat   OTR_COMPAT_EXPORT QuatFromYPR   (const double YPR[]);
-double  OTR_COMPAT_EXPORT AngleBetween  (const tQuat S, const tQuat D);
-tQuat   OTR_COMPAT_EXPORT Slerp         (const tQuat S, const tQuat D, const double alpha);
-void    OTR_COMPAT_EXPORT QuatToYPR     (const tQuat Q, double YPR[]);
+double  OTR_COMPAT_EXPORT AngleBetween  (const tQuat& S, const tQuat& D);
+tQuat   OTR_COMPAT_EXPORT Slerp         (const tQuat& S, const tQuat& D, const double alpha);
+void    OTR_COMPAT_EXPORT QuatToYPR     (const tQuat& Q, double YPR[]);
-- 
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