ksys/phys: Introduce {First,Last}{Entity,Sensor} constants to improve clarity

src/KingSystem/Physics/RigidBody/physRigidBody.cpp

@@ -555,7 +555,7 @@ void RigidBody::setCollidableQualityType(hkpCollidableQualityType quality) {
 static int getLayerBit(int layer, ContactLayerType type) {
     // This is layer for Entity layers and layer - 0x20 for Sensor layers.
     // XXX: this should be using makeContactLayerMask.
-    return layer - ContactLayer::SensorObject * int(type);
+    return layer - FirstSensor * int(type);
 }
 
 void RigidBody::addContactLayer(ContactLayer layer) {

src/KingSystem/Physics/System/physDefines.cpp

@@ -9,20 +9,19 @@ ContactLayerType getContactLayerType(ContactLayer layer) {
 }
 
 u32 makeContactLayerMask(ContactLayer layer) {
-    if (layer < ContactLayer::SensorObject)
+    if (layer < FirstSensor)
         return 1 << layer;
-    return 1 << (layer - ContactLayer::SensorObject);
+    return 1 << (layer - FirstSensor);
 }
 
 u32 getContactLayerBase(ContactLayerType type) {
     if (type == ContactLayerType::Entity)
-        return ContactLayer::EntityObject;
-    return ContactLayer::SensorObject;
+        return FirstEntity;
+    return FirstSensor;
 }
 
 u32 getContactLayerBaseRelativeValue(ContactLayer layer) {
-    return layer - (layer < ContactLayer::SensorObject ? ContactLayer::EntityObject :
-                                                         ContactLayer::SensorObject);
+    return layer - (layer < FirstSensor ? FirstEntity : FirstSensor);
 }
 
 const char* contactLayerToText(ContactLayer layer) {

src/KingSystem/Physics/System/physDefines.h

@@ -74,6 +74,12 @@ SensorEnd)
 
 constexpr int MaxNumLayersPerType = 32;
 
+constexpr auto FirstEntity = ContactLayer::EntityObject;
+constexpr auto LastEntity = ContactLayer::EntityMeshVisualizer;
+
+constexpr auto FirstSensor = ContactLayer::SensorObject;
+constexpr auto LastSensor = ContactLayer::SensorCustomReceiver;
+
 SEAD_ENUM(Material,
 Undefined,\
 Soil,\
@@ -192,7 +198,7 @@ union ReceiverMask {
 union EntityCollisionFilterInfo {
     union Data {
         ContactLayer getLayer() const { return int(layer); }
-        ContactLayer getLayerSensor() const { return int(layer + ContactLayer::SensorObject); }
+        ContactLayer getLayerSensor() const { return int(layer + FirstSensor); }
         GroundHit getGroundHit() const { return int(ground_hit); }
 
         util::BitField<0, 5, u32> layer;

src/KingSystem/Physics/System/physSystem.cpp

@@ -31,9 +31,8 @@ void System::initSystemData(sead::Heap* heap) {
     res::registerEntryFactory(new (heap) res::EntryFactory<RagdollControllerKeyList>(1.0, 0x4000),
                               "brgcon");
 
-    mEntityGroupFilter = EntityGroupFilter::make(ContactLayer::EntityObject,
-                                                 ContactLayer::EntityMeshVisualizer, heap);
-    mSensorGroupFilter = SensorGroupFilter::make(ContactLayer::SensorCustomReceiver, heap);
+    mEntityGroupFilter = EntityGroupFilter::make(FirstEntity, LastEntity, heap);
+    mSensorGroupFilter = SensorGroupFilter::make(LastSensor, heap);
     mGroupFilters.pushBack(mEntityGroupFilter);
     mGroupFilters.pushBack(mSensorGroupFilter);