add Ragdoll::_accumulatedMovement

libraries/shared/src/Ragdoll.cpp

@@ -19,7 +19,8 @@
 #include "PhysicsSimulation.h"
 #include "SharedUtil.h" // for EPSILON
 
-Ragdoll::Ragdoll() : _massScale(1.0f), _translation(0.0f), _translationInSimulationFrame(0.0f), _simulation(NULL) {
+Ragdoll::Ragdoll() : _massScale(1.0f), _translation(0.0f), _translationInSimulationFrame(0.0f), 
+        _accumulatedMovement(0.0f), _simulation(NULL) {
 }
 
 Ragdoll::~Ragdoll() {
@@ -116,3 +117,27 @@ void Ragdoll::setMassScale(float scale) {
         _massScale = scale;
     }
 }
+
+void Ragdoll::removeRootOffset(bool accumulateMovement) {
+    const int numPoints = _points.size();
+    if (numPoints > 0) {
+        // shift all points so that the root aligns with the the ragdoll's position in the simulation
+        glm::vec3 offset = _translationInSimulationFrame - _points[0]._position;
+        float offsetLength = glm::length(offset);
+        if (offsetLength > EPSILON) {
+            for (int i = 0; i < numPoints; ++i) {
+                _points[i].shift(offset);
+            }
+            const float MIN_ROOT_OFFSET = 0.02f;
+            if (accumulateMovement && offsetLength > MIN_ROOT_OFFSET) {
+                _accumulatedMovement -= (1.0f - MIN_ROOT_OFFSET / offsetLength) * offset;
+            }
+        }
+    }
+}
+
+glm::vec3 Ragdoll::getAndClearAccumulatedMovement() {
+    glm::vec3 movement = _accumulatedMovement;
+    _accumulatedMovement = glm::vec3(0.0f);
+    return movement;
+}

libraries/shared/src/Ragdoll.h

@@ -56,6 +56,10 @@ public:
     virtual void initPoints() = 0;
     virtual void buildConstraints() = 0;
 
+    void removeRootOffset(bool accumulateMovement);
+
+    glm::vec3 getAndClearAccumulatedMovement();
+
 protected:
     float _massScale;
     glm::vec3 _translation;  // world-frame
@@ -66,6 +70,12 @@ protected:
     QVector<VerletPoint> _points;
     QVector<DistanceConstraint*> _boneConstraints;
     QVector<FixedConstraint*> _fixedConstraints;
+
+    // The collisions are typically done in a simulation frame that is slaved to the center of one of the Ragdolls.
+    // To allow the Ragdoll to provide feedback of its own displacement we store it in _accumulatedMovement.
+    // The owner of the Ragdoll can harvest this displacement to update the rest of the object positions in the simulation.
+    glm::vec3 _accumulatedMovement;
+
 private:
     void updateSimulationTransforms(const glm::vec3& translation, const glm::quat& rotation);