use dynamic constraints for IK

libraries/animation/src/AnimInverseKinematics.cpp

@@ -396,6 +396,17 @@ const AnimPoseVec& AnimInverseKinematics::overlay(const AnimVariantMap& animVars
             }
             _relativePoses[i].trans = underPoses[i].trans;
         }
+
+        if (!_relativePoses.empty()) {
+            // Sometimes the underpose itself can violate the constraints.  Rather than
+            // clamp the animation we dynamically expand each constraint to accomodate it.
+            std::map<int, RotationConstraint*>::iterator constraintItr = _constraints.begin();
+            while (constraintItr != _constraints.end()) {
+                int index = constraintItr->first;
+                constraintItr->second->dynamicallyAdjustLimits(_relativePoses[index].rot);
+                ++constraintItr;
+            }
+        }
     }
 
     if (!_relativePoses.empty()) {

libraries/animation/src/RotationConstraint.h

@@ -31,6 +31,10 @@ public:
     /// \return true if this constraint is part of lower spine
     virtual bool isLowerSpine() const { return false; }
 
+    /// \param rotation rotation to allow
+    /// \brief clear previous adjustment and adjust constraint limits to allow rotation
+    virtual void dynamicallyAdjustLimits(const glm::quat& rotation) {}
+
 protected:
     glm::quat _referenceRotation = glm::quat();
 };

libraries/animation/src/SwingTwistConstraint.h

@@ -55,7 +55,7 @@ public:
 
     /// \param rotation rotation to allow
     /// \brief clear previous adjustment and adjust constraint limits to allow rotation
-    void dynamicallyAdjustLimits(const glm::quat& rotation);
+    virtual void dynamicallyAdjustLimits(const glm::quat& rotation) override;
 
     // for testing purposes
     const std::vector<float>& getMinDots() { return _swingLimitFunction.getMinDots(); }