like that

panda/src/lerp/lerpfunctor.h

@@ -41,12 +41,11 @@ private:
 
 template <class value>
 class SimpleLerpFunctor : public LerpFunctor {
-private:
+protected:
   value _start;
   value _end;
   value _diff_cache;
 
-protected:
   value interpolate(float);
   SimpleLerpFunctor(value start, value end) : LerpFunctor(), _start(start),
 					      _end(end), _diff_cache(end-start)

panda/src/sgmanip/nodePathLerps.cxx

@@ -37,6 +37,26 @@ void PosLerpFunctor::operator()(float t) {
 HprLerpFunctor::HprLerpFunctor(const HprLerpFunctor& c)
   : LVecBase3fLerpFunctor(c), _node_path(c._node_path) {}
 
+void HprLerpFunctor::take_shortest(void) {
+  // so long as these are actually degrees
+  for (int i=0; i!=3; ++i)
+    if (this->_diff_cache[i] < -180.)
+      _start[i] -= 360.;
+    else if (this->_diff_cache[i] > 180.)
+      _start[i] += 360.;
+  this->_diff_cache = this->_end - this->_start;
+}
+
+void HprLerpFunctor::take_longest(void) {
+  // so long as these are actually degrees
+  for (int i=0; i!=3; ++i)
+    if ((this->_diff_cache[i] < 0.) && (this->_diff_cache[i] > -180.))
+      _start[i] -= 360.;
+    else if ((this->_diff_cache[i] >= 0.) && (this->_diff_cache[i] < 180))
+      _start[i] += 360.;
+  this->_diff_cache = this->_end - this->_start;
+}
+
 HprLerpFunctor::~HprLerpFunctor(void)
 {
 }
@@ -95,6 +115,26 @@ void ColorLerpFunctor::operator()(float t) {
 PosHprLerpFunctor::PosHprLerpFunctor(const PosHprLerpFunctor& c)
   : LerpFunctor(c), _node_path(c._node_path) {}
 
+void PosHprLerpFunctor::take_shortest(void) {
+  // so long as these are actually degrees
+  for (int i=0; i!=3; ++i)
+    if (this->_hdiff_cache[i] < -180.)
+      _hstart[i] -= 360.;
+    else if (this->_hdiff_cache[i] > 180.)
+      _hstart[i] += 360.;
+  this->_hdiff_cache = this->_hend - this->_hstart;
+}
+
+void PosHprLerpFunctor::take_longest(void) {
+  // so long as these are actually degrees
+  for (int i=0; i!=3; ++i)
+    if ((this->_hdiff_cache[i] < 0.) && (this->_hdiff_cache[i] > -180.))
+      _hstart[i] -= 360.;
+    else if ((this->_hdiff_cache[i] >= 0.) && (this->_hdiff_cache[i] < 180))
+      _hstart[i] += 360.;
+  this->_hdiff_cache = this->_hend - this->_hstart;
+}
+
 PosHprLerpFunctor::~PosHprLerpFunctor(void)
 {
 }
@@ -123,6 +163,26 @@ void PosHprLerpFunctor::operator()(float t) {
 PosHprScaleLerpFunctor::PosHprScaleLerpFunctor(const PosHprScaleLerpFunctor& c)
   : LerpFunctor(c), _node_path(c._node_path) {}
 
+void PosHprScaleLerpFunctor::take_shortest(void) {
+  // so long as these are actually degrees
+  for (int i=0; i!=3; ++i)
+    if (this->_hdiff_cache[i] < -180.)
+      _hstart[i] -= 360.;
+    else if (this->_hdiff_cache[i] > 180.)
+      _hstart[i] += 360.;
+  this->_hdiff_cache = this->_hend - this->_hstart;
+}
+
+void PosHprScaleLerpFunctor::take_longest(void) {
+  // so long as these are actually degrees
+  for (int i=0; i!=3; ++i)
+    if ((this->_hdiff_cache[i] < 0.) && (this->_hdiff_cache[i] > -180.))
+      _hstart[i] -= 360.;
+    else if ((this->_hdiff_cache[i] >= 0.) && (this->_hdiff_cache[i] < 180))
+      _hstart[i] += 360.;
+  this->_hdiff_cache = this->_hend - this->_hstart;
+}
+
 PosHprScaleLerpFunctor::~PosHprScaleLerpFunctor(void)
 {
 }

panda/src/sgmanip/nodePathLerps.h

@@ -87,6 +87,8 @@ PUBLISHED:
 		 float ez, NodePath wrt)
     : LVecBase3fLerpFunctor(LVecBase3f(sx, sy, sz), LVecBase3f(ex, ey, ez)),
       _node_path(np), _is_wrt(true), _wrt_path(wrt) {}
+  void take_shortest(void);
+  void take_longest(void);
 
 public:
   HprLerpFunctor(const HprLerpFunctor&);
@@ -260,6 +262,8 @@ PUBLISHED:
       _pend(pex, pey, pez), _pdiff_cache(_pend-_pstart),
       _hstart(hsx, hsy, hsz), _hend(hex, hey, hez),
       _hdiff_cache(_hend - _hstart), _is_wrt(true), _wrt_path(wrt) {}
+  void take_shortest(void);
+  void take_longest(void);
 
 public:
   PosHprLerpFunctor(const PosHprLerpFunctor&);
@@ -343,6 +347,8 @@ PUBLISHED:
       _hdiff_cache(_hend-_hstart), _sstart(ssx, ssy, ssz),
       _send(sex, sey, sez), _sdiff_cache(_send-_sstart), _is_wrt(true),
       _wrt_path(wrt) {}
+  void take_shortest(void);
+  void take_longest(void);
 
 public:
   PosHprScaleLerpFunctor(const PosHprScaleLerpFunctor&);