From 8a6da4d6210192ada4a26ddd397c00d78b08dfcc Mon Sep 17 00:00:00 2001
From: Nat Goodspeed <nat@lindenlab.com>
Date: Thu, 26 Sep 2024 13:48:58 -0400
Subject: Rename our lerp() to flerp(); call where MSVC balks at std::lerp().

Now the lerp() in global namespace is std::lerp(), but it remains true that
for some calls to std::lerp(), MSVC issues fatal argument conversion warnings.
In those places, call flerp() (our historic lerp()) instead.
---
 indra/llmath/llmath.h     |  8 ++++----
 indra/llmath/llvolume.cpp | 28 ++++++++++++++--------------
 2 files changed, 18 insertions(+), 18 deletions(-)

(limited to 'indra/llmath')

diff --git a/indra/llmath/llmath.h b/indra/llmath/llmath.h
index 75284ef57e..1d6d986207 100644
--- a/indra/llmath/llmath.h
+++ b/indra/llmath/llmath.h
@@ -358,11 +358,11 @@ inline F32 snap_to_sig_figs(F32 foo, S32 sig_figs)
     return new_foo;
 }
 
+using std::lerp;
 // Even though there's now a std::lerp() function that appears to do the same
-// as this function, for some reason MSVC likes this one better. Publishing
-// std::lerp() into the global namespace instead of defining this function
-// results in fatal argument conversion warnings.
-inline F32 lerp(F32 a, F32 b, F32 u)
+// as this function, in some cases MSVC likes this one better: some calls to
+// std::lerp() produce fatal argument conversion warnings.
+inline F32 flerp(F32 a, F32 b, F32 u)
 {
     return a + ((b - a) * u);
 }
diff --git a/indra/llmath/llvolume.cpp b/indra/llmath/llvolume.cpp
index 700e61467b..275e5bcb43 100644
--- a/indra/llmath/llvolume.cpp
+++ b/indra/llmath/llvolume.cpp
@@ -1294,9 +1294,9 @@ void LLPath::genNGon(const LLPathParams& params, S32 sides, F32 startOff, F32 en
     c       = cos(ang)*lerp(radius_start, radius_end, t);
 
 
-    pt->mPos.set(0 + lerp(0,params.getShear().mV[0],s)
-                      + lerp(-skew ,skew, t) * 0.5f,
-                    c + lerp(0,params.getShear().mV[1],s),
+    pt->mPos.set(0 + flerp(0,params.getShear().mV[0],s)
+                      + flerp(-skew ,skew, t) * 0.5f,
+                    c + flerp(0,params.getShear().mV[1],s),
                     s);
     pt->mScale.set(hole_x * lerp(taper_x_begin, taper_x_end, t),
         hole_y * lerp(taper_y_begin, taper_y_end, t),
@@ -1327,9 +1327,9 @@ void LLPath::genNGon(const LLPathParams& params, S32 sides, F32 startOff, F32 en
         c   = cos(ang)*lerp(radius_start, radius_end, t);
         s   = sin(ang)*lerp(radius_start, radius_end, t);
 
-        pt->mPos.set(0 + lerp(0,params.getShear().mV[0],s)
-                          + lerp(-skew ,skew, t) * 0.5f,
-                        c + lerp(0,params.getShear().mV[1],s),
+        pt->mPos.set(0 + flerp(0,params.getShear().mV[0],s)
+                          + flerp(-skew ,skew, t) * 0.5f,
+                        c + flerp(0,params.getShear().mV[1],s),
                         s);
 
         pt->mScale.set(hole_x * lerp(taper_x_begin, taper_x_end, t),
@@ -1354,9 +1354,9 @@ void LLPath::genNGon(const LLPathParams& params, S32 sides, F32 startOff, F32 en
     c   = cos(ang)*lerp(radius_start, radius_end, t);
     s   = sin(ang)*lerp(radius_start, radius_end, t);
 
-    pt->mPos.set(0 + lerp(0,params.getShear().mV[0],s)
-                      + lerp(-skew ,skew, t) * 0.5f,
-                    c + lerp(0,params.getShear().mV[1],s),
+    pt->mPos.set(0 + flerp(0,params.getShear().mV[0],s)
+                      + flerp(-skew ,skew, t) * 0.5f,
+                    c + flerp(0,params.getShear().mV[1],s),
                     s);
     pt->mScale.set(hole_x * lerp(taper_x_begin, taper_x_end, t),
                    hole_y * lerp(taper_y_begin, taper_y_end, t),
@@ -1494,8 +1494,8 @@ bool LLPath::generate(const LLPathParams& params, F32 detail, S32 split,
             for (S32 i=0;i<np;i++)
             {
                 F32 t = lerp(params.getBegin(),params.getEnd(),(F32)i * mStep);
-                mPath[i].mPos.set(lerp(0,params.getShear().mV[0],t),
-                                     lerp(0,params.getShear().mV[1],t),
+                mPath[i].mPos.set(flerp(0,params.getShear().mV[0],t),
+                                     flerp(0,params.getShear().mV[1],t),
                                      t - 0.5f);
                 LLQuaternion quat;
                 quat.setQuat(lerp(F_PI * params.getTwistBegin(),F_PI * params.getTwist(),t),0,0,1);
@@ -1559,10 +1559,10 @@ bool LLPath::generate(const LLPathParams& params, F32 detail, S32 split,
         {
             F32 t = (F32)i * mStep;
             mPath[i].mPos.set(0,
-                                lerp(0,   -sin(F_PI*params.getTwist()*t)*0.5f,t),
+                                flerp(0,   -sin(F_PI*params.getTwist()*t)*0.5f,t),
                                 lerp(-0.5f, cos(F_PI*params.getTwist()*t)*0.5f,t));
-            mPath[i].mScale.set(lerp(1,params.getScale().mV[0],t),
-                                lerp(1,params.getScale().mV[1],t), 0,1);
+            mPath[i].mScale.set(flerp(1,params.getScale().mV[0],t),
+                                flerp(1,params.getScale().mV[1],t), 0,1);
             mPath[i].mTexT  = t;
             LLQuaternion quat;
             quat.setQuat(F_PI * params.getTwist() * t,1,0,0);
-- 
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