From 964c733f53812a46304767a2f3ffbab6167c1169 Mon Sep 17 00:00:00 2001
From: maelstrom <maelstrom@maelstrom.dev>
Date: Fri, 30 May 2025 02:15:58 +0200
Subject: [PATCH] feat(physics): parts fallen beyond fall height get
 automatically destroyed

---
 core/src/objects/workspace.cpp | 11 +++++++++--
 core/src/objects/workspace.h   |  2 ++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/core/src/objects/workspace.cpp b/core/src/objects/workspace.cpp
index 694ec66..4b830fe 100644
--- a/core/src/objects/workspace.cpp
+++ b/core/src/objects/workspace.cpp
@@ -127,17 +127,19 @@ void Workspace::PhysicsStep(float deltaTime) {
     // Step the simulation a few steps
     physicsWorld->update(std::min(deltaTime / 2, (1/60.f)));
 
-    // Naive implementation. Parts are only considered so if they are just under Workspace
     // TODO: Add list of tracked parts in workspace based on their ancestry using inWorkspace property of Instance
     for (auto it = this->GetDescendantsStart(); it != this->GetDescendantsEnd(); it++) {
         std::shared_ptr<Instance> obj = *it;
-        if (obj->GetClass()->className != "Part") continue; // TODO: Replace this with a .IsA call instead of comparing the class name directly
+        if (!obj->IsA<Part>()) continue;
         std::shared_ptr<Part> part = std::dynamic_pointer_cast<Part>(obj);
+
+        // Sync properties
         const rp::Transform& transform = part->rigidBody->getTransform();
         part->cframe = CFrame(transform);
         part->velocity = part->rigidBody->getLinearVelocity();
 
         // part->rigidBody->enableGravity(true);
+        // RotateV/Motor joint
         for (auto& joint : part->secondaryJoints) {
             if (joint.expired() || !joint.lock()->IsA("RotateV")) continue;
                         
@@ -146,6 +148,11 @@ void Workspace::PhysicsStep(float deltaTime) {
             // part->rigidBody->enableGravity(false);
             part->rigidBody->setAngularVelocity(-(motor->part0.lock()->cframe * motor->c0).LookVector() * rate);
         }
+
+        // Destroy fallen parts
+        if (part->cframe.Position().Y() < this->fallenPartsDestroyHeight) {
+            part->Destroy();
+        }
     }
 }
 
diff --git a/core/src/objects/workspace.h b/core/src/objects/workspace.h
index 934b326..cf5c34b 100644
--- a/core/src/objects/workspace.h
+++ b/core/src/objects/workspace.h
@@ -66,6 +66,8 @@ public:
     Workspace();
     ~Workspace();
 
+    DEF_PROP float fallenPartsDestroyHeight = -500;
+
     // static inline std::shared_ptr<Workspace> New() { return std::make_shared<Workspace>(); };
     static inline std::shared_ptr<Instance> Create() { return std::make_shared<Workspace>(); };