From c2dcd3aac39843c99ee8988704f10b67b6dbc2ef Mon Sep 17 00:00:00 2001
From: Panos Karabelas <panosconroe@hotmail.com>
Date: Tue, 7 Jan 2025 01:24:11 +0000
Subject: [PATCH] [physicsbody] reduced the number of rigid bodies that would
 be created when initializing a physics body (due to property changes
 requiring rigid body recreation)

---
 runtime/Game/Game.cpp                    | 19 +++++++++--------
 runtime/World/Components/PhysicsBody.cpp | 26 +++++-------------------
 runtime/World/Components/PhysicsBody.h   |  5 +++--
 3 files changed, 19 insertions(+), 31 deletions(-)

diff --git a/runtime/Game/Game.cpp b/runtime/Game/Game.cpp
index fc0ee5fde..7cf7d8c35 100644
--- a/runtime/Game/Game.cpp
+++ b/runtime/Game/Game.cpp
@@ -99,9 +99,9 @@ namespace Spartan
             renderable->GetMaterial()->SetProperty(MaterialProperty::TextureTilingY, entity->GetScale().z);
             
             // add physics components
-            shared_ptr<PhysicsBody> rigid_body = entity->AddComponent<PhysicsBody>();
-            rigid_body->SetMass(0.0f); // static
-            rigid_body->SetShapeType(PhysicsShape::StaticPlane);
+            shared_ptr<PhysicsBody> physics_body = entity->AddComponent<PhysicsBody>();
+            physics_body->SetShapeType(PhysicsShape::StaticPlane);
+            physics_body->SetMass(0.0f);
         }
 
         void create_camera(const Vector3& camera_position = Vector3(0.0f, 2.0f, -10.0f), const Vector3& camera_rotation = Vector3(0.0f, 0.0f, 0.0f))
@@ -414,9 +414,9 @@ namespace Spartan
                 renderable->SetMaterial(material);
 
                 // add physics components
-                shared_ptr<PhysicsBody> rigid_body = entity->AddComponent<PhysicsBody>();
-                rigid_body->SetMass(15.0f);
-                rigid_body->SetShapeType(PhysicsShape::Box);
+                shared_ptr<PhysicsBody> physics_body = entity->AddComponent<PhysicsBody>();
+                physics_body->SetShapeType(PhysicsShape::Box);
+                physics_body->SetMass(15.0f);
             }
 
             // flight helmet
@@ -437,6 +437,7 @@ namespace Spartan
                 entity->SetScale(Vector3(0.3f, 0.3f, 0.3f));
 
                 PhysicsBody* physics_body = entity->AddComponent<PhysicsBody>().get();
+                physics_body->SetShapeType(PhysicsShape::MeshConvexHull);
                 physics_body->SetMass(8.0f);
             }
 
@@ -451,6 +452,7 @@ namespace Spartan
                 if (auto mesh_entity = entity->GetDescendantByName("Object_2"))
                 {
                     PhysicsBody* physics_body = mesh_entity->AddComponent<PhysicsBody>().get();
+                    physics_body->SetShapeType(PhysicsShape::MeshConvexHull);
                     physics_body->SetMass(8.0f);
                 }
             }
@@ -562,8 +564,9 @@ namespace Spartan
                 // add water and vegetation
                 {
                     // add physics so we can walk on it
-                    PhysicsBody* rigid_body = m_default_terrain->AddComponent<PhysicsBody>().get();
-                    rigid_body->SetMass(0.0f);
+                    PhysicsBody* physics_body = m_default_terrain->AddComponent<PhysicsBody>().get();
+                    physics_body->SetShapeType(PhysicsShape::Terrain);
+                    physics_body->SetMass(0.0f);
    
                     // water
                     {
diff --git a/runtime/World/Components/PhysicsBody.cpp b/runtime/World/Components/PhysicsBody.cpp
index 8d7cce4f1..2e7a08ac7 100644
--- a/runtime/World/Components/PhysicsBody.cpp
+++ b/runtime/World/Components/PhysicsBody.cpp
@@ -179,16 +179,6 @@ namespace Spartan
         SP_REGISTER_ATTRIBUTE_VALUE_VALUE(m_center_of_mass, Vector3);
         SP_REGISTER_ATTRIBUTE_VALUE_VALUE(m_size, Vector3);
         SP_REGISTER_ATTRIBUTE_VALUE_SET(m_shape_type, SetShapeType, PhysicsShape);
-
-        if (GetEntity()->GetComponent<Renderable>())
-        {
-            m_shape_type = PhysicsShape::MeshConvexHull;
-        }
-
-        if (GetEntity()->GetComponent<Terrain>())
-        {
-            m_shape_type = PhysicsShape::Terrain;
-        }
     }
 
     PhysicsBody::~PhysicsBody()
@@ -199,7 +189,6 @@ namespace Spartan
     void PhysicsBody::OnInitialize()
     {
         Component::OnInitialize();
-        UpdateShape();
     }
 
     void PhysicsBody::OnRemove()
@@ -582,7 +571,11 @@ namespace Spartan
 
     void PhysicsBody::AddBodyToWorld()
     {
-        SP_ASSERT(shape != nullptr);
+        if (!shape)
+        {
+            SP_LOG_WARNING("To modify the physics body of \"%s\", you need to first call SetShapeType()", GetEntity()->GetObjectName().c_str());
+            return;
+        }
 
         // compute local inertia so that we can transfer it to the new body
         btVector3 inertia = btVector3(0, 0, 0);
@@ -728,15 +721,6 @@ namespace Spartan
         if (m_shape_type == type)
             return;
 
-        if (type == PhysicsShape::Terrain)
-        {
-            if (!m_entity_ptr->GetComponent<Terrain>())
-            {
-                SP_LOG_WARNING("Can't set terrain shape as there is no terrain component");
-                return;
-            }
-        }
-
         m_shape_type = type;
         UpdateShape();
     }
diff --git a/runtime/World/Components/PhysicsBody.h b/runtime/World/Components/PhysicsBody.h
index 726d7d74a..12c39f8fc 100644
--- a/runtime/World/Components/PhysicsBody.h
+++ b/runtime/World/Components/PhysicsBody.h
@@ -57,7 +57,8 @@ namespace Spartan
         Cone,
         Terrain,
         MeshConvexHull,
-        Mesh
+        Mesh,
+        Max
     };
 
     class PhysicsBody : public Component
@@ -177,7 +178,7 @@ namespace Spartan
         Math::Vector3 m_rotation_lock  = Math::Vector3::Zero;
         Math::Vector3 m_center_of_mass = Math::Vector3::Zero;
         Math::Vector3 m_size           = Math::Vector3::One;
-        PhysicsShape m_shape_type      = PhysicsShape::Box;
+        PhysicsShape m_shape_type      = PhysicsShape::Max;
         PhysicsBodyType m_body_type    = PhysicsBodyType::RigidBody;
         uint32_t terrain_width         = 0;
         uint32_t terrain_length        = 0;