fix(physics): motor joint updates with paramB

core/src/objects/joint/jointinstance.cpp

@@ -17,6 +17,9 @@ void JointInstance::OnAncestryChanged(nullable std::shared_ptr<Instance>, nullab
     Update();
 }
 
+void JointInstance::OnPartParamsUpdated() {
+}
+
 void JointInstance::Update() {
     // To keep it simple compared to our previous algorithm, this one is pretty barebones:
     // 1. Every time we update, (whether our parent changed, or a property), destroy the current joints

core/src/objects/joint/jointinstance.h

@@ -3,7 +3,6 @@
 #include "objects/base/instance.h"
 #include "../annotation.h"
 #include <memory>
-#include <optional>
 #include "datatypes/cframe.h"
 #include "physics/world.h"
 
@@ -12,6 +11,8 @@
 #include "objects/part/part.h"
 #endif
 
+#define DEF_PROP_PHYS DEF_PROP_(on_update=onUpdated)
+
 class BasePart;
 class Workspace;
 
@@ -33,12 +34,15 @@ protected:
     virtual void buildJoint() = 0;
 public:
     void Update();
+    virtual void OnPartParamsUpdated();
 
-    DEF_PROP_(on_update=onUpdated) std::weak_ptr<BasePart> part0;
+    DEF_PROP_PHYS std::weak_ptr<BasePart> part0;
-    DEF_PROP_(on_update=onUpdated) std::weak_ptr<BasePart> part1;
+    DEF_PROP_PHYS std::weak_ptr<BasePart> part1;
-    DEF_PROP_(on_update=onUpdated) CFrame c0;
+    DEF_PROP_PHYS CFrame c0;
-    DEF_PROP_(on_update=onUpdated) CFrame c1;
+    DEF_PROP_PHYS CFrame c1;
 
     JointInstance(const InstanceType*);
     ~JointInstance();
-};
+};
+
+#undef DEF_PROP_PHYS

core/src/objects/joint/rotatev.cpp

@@ -21,8 +21,14 @@ void RotateV::buildJoint() {
     CFrame newFrame = part0.lock()->cframe * (c0 * c1.Inverse());
     part1.lock()->cframe = newFrame;
     // Do NOT use Abs() in this scenario. For some reason that breaks it
-    PhysRotatingJointInfo jointInfo(c0, c1, true);
+    float vel = part0.lock()->GetSurfaceParamB(-c0.LookVector().Unit()) * 6.28;
+    PhysRotatingJointInfo jointInfo(c0, c1, vel);
     
     this->joint = workspace->CreateJoint(jointInfo, part0.lock(), part1.lock());
     jointWorkspace = workspace;
+}
+
+void RotateV::OnPartParamsUpdated() {
+    float vel = part0.lock()->GetSurfaceParamB(-c0.LookVector().Unit()) * 6.28;
+    this->joint.setAngularVelocity(vel);
 }

core/src/objects/joint/rotatev.h

@@ -13,6 +13,8 @@ public:
     RotateV();
     ~RotateV();
 
+    void OnPartParamsUpdated() override;
+
     static inline std::shared_ptr<RotateV> New() { return std::make_shared<RotateV>(); };
     static inline std::shared_ptr<Instance> Create() { return std::make_shared<RotateV>(); };
 };

core/src/objects/part/basepart.cpp

@@ -70,6 +70,15 @@ void BasePart::onUpdated(std::string property) {
         BreakJoints();
 }
 
+void BasePart::onParamUpdated(std::string property) {
+    // Send signal to joints to update themselves
+    for (std::weak_ptr<JointInstance> joint : primaryJoints) {
+        if (joint.expired()) continue;
+
+        joint.lock()->OnPartParamsUpdated();
+    }
+}
+
 // Expands provided extents to fit point
 static void expandMaxExtents(Vector3* min, Vector3* max, Vector3 point) {
     *min = Vector3(glm::min(min->X(), point.X()), glm::min(min->Y(), point.Y()), glm::min(min->Z(), point.Z()));

core/src/objects/part/basepart.h

@@ -14,6 +14,10 @@
 #include "objects/pvinstance.h"
 #include "physics/world.h"
 
+// Common macro for part properties
+#define DEF_PROP_PHYS DEF_PROP_(on_update=onUpdated)
+#define DEF_PROP_PHYSPARAM DEF_PROP_(on_update=onParamUpdated)
+
 // For easy construction from C++. Maybe should be removed?
 struct PartConstructParams {
     Vector3 position;
@@ -51,19 +55,20 @@ protected:
     virtual void OnWorkspaceRemoved(std::shared_ptr<Workspace> oldWorkspace) override;
     void OnAncestryChanged(nullable std::shared_ptr<Instance> child, nullable std::shared_ptr<Instance> newParent) override;
     void onUpdated(std::string);
+    void onParamUpdated(std::string);
 
     BasePart(const InstanceType*);
     BasePart(const InstanceType*, PartConstructParams params);
 public:
     DEF_PROP_CATEGORY(DATA)
-    DEF_PROP_(on_update=onUpdated) Vector3 velocity;
+    DEF_PROP_PHYS Vector3 velocity;
     [[ def_prop(name="CFrame", on_update=onUpdated), cframe_position_prop(name="Position"), cframe_rotation_prop(name="Rotation") ]]
     CFrame cframe;
 
     DEF_PROP_CATEGORY(PART)
     // Special compatibility changes for this property were made in
     // Instance::Serialize
-    DEF_PROP_(on_update=onUpdated) Vector3 size;
+    DEF_PROP_PHYS Vector3 size;
 
     DEF_PROP_CATEGORY(APPEARANCE)
     DEF_PROP Color3 color;
@@ -71,8 +76,8 @@ public:
     DEF_PROP float reflectance = 0.f;
     
     DEF_PROP_CATEGORY(BEHAVIOR)
-    DEF_PROP_(on_update=onUpdated) bool anchored = false;
+    DEF_PROP_PHYS bool anchored = false;
-    DEF_PROP_(on_update=onUpdated) bool canCollide = true;
+    DEF_PROP_PHYS bool canCollide = true;
     DEF_PROP bool locked = false;
 
     DEF_PROP_CATEGORY(SURFACE)
@@ -84,19 +89,19 @@ public:
     DEF_PROP SurfaceType backSurface = SurfaceType::Smooth;
 
     DEF_PROP_CATEGORY(SURFACE_INPUT)
-    DEF_PROP float topParamA = -0.5;
+    DEF_PROP_PHYSPARAM float topParamA = -0.5;
-    DEF_PROP float bottomParamA = -0.5;
+    DEF_PROP_PHYSPARAM float bottomParamA = -0.5;
-    DEF_PROP float leftParamA = -0.5;
+    DEF_PROP_PHYSPARAM float leftParamA = -0.5;
-    DEF_PROP float rightParamA = -0.5;
+    DEF_PROP_PHYSPARAM float rightParamA = -0.5;
-    DEF_PROP float frontParamA = -0.5;
+    DEF_PROP_PHYSPARAM float frontParamA = -0.5;
-    DEF_PROP float backParamA = -0.5;
+    DEF_PROP_PHYSPARAM float backParamA = -0.5;
 
-    DEF_PROP float topParamB = 0.5;
+    DEF_PROP_PHYSPARAM float topParamB = 0.5;
-    DEF_PROP float bottomParamB = 0.5;
+    DEF_PROP_PHYSPARAM float bottomParamB = 0.5;
-    DEF_PROP float leftParamB = 0.5;
+    DEF_PROP_PHYSPARAM float leftParamB = 0.5;
-    DEF_PROP float rightParamB = 0.5;
+    DEF_PROP_PHYSPARAM float rightParamB = 0.5;
-    DEF_PROP float frontParamB = 0.5;
+    DEF_PROP_PHYSPARAM float frontParamB = 0.5;
-    DEF_PROP float backParamB = 0.5;
+    DEF_PROP_PHYSPARAM float backParamB = 0.5;
 
     DEF_SIGNAL SignalSource Touched;
     DEF_SIGNAL SignalSource TouchEnded;
@@ -117,4 +122,7 @@ public:
 
     // Calculate size of axis-aligned bounding box
     Vector3 GetAABB();
-};
+};
+
+#undef DEF_PROP_PHYS
+#undef DEF_PROP_PHYSPARAM

core/src/physics/world.cpp

@@ -229,9 +229,8 @@ PhysJoint PhysWorld::createJoint(PhysJointInfo& type, std::shared_ptr<BasePart>
         // settings.mMotorSettings = JPH::MotorSettings(1.0f, 1.0f);
         constraint = settings.Create(*part0->rigidBody.bodyImpl, *part1->rigidBody.bodyImpl);
         if (info->motorized) {
-            float vel = part0->GetSurfaceParamB(-info->c0.LookVector().Unit()) * 6.28;
             static_cast<JPH::HingeConstraint*>(constraint)->SetMotorState(JPH::EMotorState::Velocity);
-            static_cast<JPH::HingeConstraint*>(constraint)->SetTargetAngularVelocity(-vel);
+            static_cast<JPH::HingeConstraint*>(constraint)->SetTargetAngularVelocity(-info->initialVelocity);
         }
     } else {
         panic();
@@ -241,6 +240,14 @@ PhysJoint PhysWorld::createJoint(PhysJointInfo& type, std::shared_ptr<BasePart>
     return { constraint };
 }
 
+// WATCH OUT! This should only be called for HingeConstraints.
+// Can't use dynamic_cast because TwoBodyConstraint is not virtual
+void PhysJoint::setAngularVelocity(float velocity) {
+    JPH::HingeConstraint* constraint = static_cast<JPH::HingeConstraint*>(jointImpl);
+    if (!constraint) return;
+    constraint->SetTargetAngularVelocity(-velocity);
+}
+
 void PhysWorld::destroyJoint(PhysJoint joint) {
     worldImpl.RemoveConstraint(joint.jointImpl);
 }

core/src/physics/world.h

@@ -17,13 +17,30 @@ class BasePart;
 class PhysWorld;
 
 struct PhysJointInfo { virtual ~PhysJointInfo() = default; protected: PhysJointInfo() = default; };
-struct PhysFixedJointInfo : PhysJointInfo { CFrame c0; CFrame c1; inline PhysFixedJointInfo(CFrame c0, CFrame c1) : c0(c0), c1(c1) {} };
+
-struct PhysRotatingJointInfo : PhysJointInfo { CFrame c0; CFrame c1; bool motorized; inline PhysRotatingJointInfo(CFrame c0, CFrame c1, bool motorized = false) : c0(c0), c1(c1), motorized(motorized) {} };
+struct PhysFixedJointInfo : PhysJointInfo {
+    CFrame c0;
+    CFrame c1;
+    
+    inline PhysFixedJointInfo(CFrame c0, CFrame c1) : c0(c0), c1(c1) {}
+};
+
+struct PhysRotatingJointInfo : PhysJointInfo {
+    CFrame c0;
+    CFrame c1;
+    bool motorized;
+    float initialVelocity;
+    
+    inline PhysRotatingJointInfo(CFrame c0, CFrame c1) : c0(c0), c1(c1), motorized(false), initialVelocity(0.f){}
+    inline PhysRotatingJointInfo(CFrame c0, CFrame c1, float initialVelocity) : c0(c0), c1(c1), motorized(true), initialVelocity(initialVelocity) {}
+};
 
 class PhysWorld;
 struct PhysJoint {
 public:
     JPH::TwoBodyConstraint* jointImpl;
+
+    void setAngularVelocity(float velocity);
 };
 
 struct RaycastResult;