diff --git a/src/api/l_physics_joints.c b/src/api/l_physics_joints.c
index 58e6c7b0..349f4fe0 100644
--- a/src/api/l_physics_joints.c
+++ b/src/api/l_physics_joints.c
@@ -5,7 +5,7 @@
 #include <lauxlib.h>
 
 void luax_pushjoint(lua_State* L, Joint* joint) {
-  switch (joint->type) {
+  switch (lovrJointGetType(joint)) {
     case JOINT_BALL: luax_pushtype(L, BallJoint, joint); break;
     case JOINT_DISTANCE: luax_pushtype(L, DistanceJoint, joint); break;
     case JOINT_HINGE: luax_pushtype(L, HingeJoint, joint); break;
diff --git a/src/api/l_physics_shapes.c b/src/api/l_physics_shapes.c
index 01493e6a..d84601bc 100644
--- a/src/api/l_physics_shapes.c
+++ b/src/api/l_physics_shapes.c
@@ -5,7 +5,7 @@
 #include <lauxlib.h>
 
 void luax_pushshape(lua_State* L, Shape* shape) {
-  switch (shape->type) {
+  switch (lovrShapeGetType(shape)) {
     case SHAPE_SPHERE: luax_pushtype(L, SphereShape, shape); break;
     case SHAPE_BOX: luax_pushtype(L, BoxShape, shape); break;
     case SHAPE_CAPSULE: luax_pushtype(L, CapsuleShape, shape); break;
diff --git a/src/api/l_physics_world.c b/src/api/l_physics_world.c
index fb580c99..ba592c63 100644
--- a/src/api/l_physics_world.c
+++ b/src/api/l_physics_world.c
@@ -161,7 +161,7 @@ static int l_lovrWorldGetColliders(lua_State* L) {
   while (collider) {
     luax_pushtype(L, Collider, collider);
     lua_rawseti(L, -2, index++);
-    collider = collider->next;
+    collider = lovrColliderGetNext(collider);
   }
 
   return 1;
diff --git a/src/modules/physics/physics.c b/src/modules/physics/physics.c
index 3a32e959..f5ca1ed5 100644
--- a/src/modules/physics/physics.c
+++ b/src/modules/physics/physics.c
@@ -3,6 +3,49 @@
 #include <stdlib.h>
 #include <stdbool.h>
 
+struct World {
+  uint32_t ref;
+  dWorldID id;
+  dSpaceID space;
+  dJointGroupID contactGroup;
+  arr_t(Shape*) overlaps;
+  char* tags[MAX_TAGS];
+  uint16_t masks[MAX_TAGS];
+  Collider* head;
+};
+
+struct Collider {
+  uint32_t ref;
+  dBodyID body;
+  World* world;
+  Collider* prev;
+  Collider* next;
+  void* userdata;
+  uint32_t tag;
+  arr_t(Shape*) shapes;
+  arr_t(Joint*) joints;
+  float friction;
+  float restitution;
+};
+
+struct Shape {
+  uint32_t ref;
+  ShapeType type;
+  dGeomID id;
+  Collider* collider;
+  void* vertices;
+  void* indices;
+  void* userdata;
+  bool sensor;
+};
+
+struct Joint {
+  uint32_t ref;
+  JointType type;
+  dJointID id;
+  void* userdata;
+};
+
 static void defaultNearCallback(void* data, dGeomID a, dGeomID b) {
   lovrWorldCollide((World*) data, dGeomGetData(a), dGeomGetData(b), -1, -1);
 }
@@ -391,6 +434,10 @@ World* lovrColliderGetWorld(Collider* collider) {
   return collider->world;
 }
 
+Collider* lovrColliderGetNext(Collider* collider) {
+  return collider->next;
+}
+
 void lovrColliderAddShape(Collider* collider, Shape* shape) {
   lovrRetain(shape);
 
diff --git a/src/modules/physics/physics.h b/src/modules/physics/physics.h
index a86fedc8..ad58a43b 100644
--- a/src/modules/physics/physics.h
+++ b/src/modules/physics/physics.h
@@ -25,59 +25,17 @@ typedef enum {
   JOINT_SLIDER
 } JointType;
 
+typedef struct World World;
 typedef struct Collider Collider;
 typedef struct Shape Shape;
 typedef struct Joint Joint;
 
-typedef struct {
-  uint32_t ref;
-  dWorldID id;
-  dSpaceID space;
-  dJointGroupID contactGroup;
-  arr_t(Shape*) overlaps;
-  char* tags[MAX_TAGS];
-  uint16_t masks[MAX_TAGS];
-  Collider* head;
-} World;
-
-struct Collider {
-  uint32_t ref;
-  dBodyID body;
-  World* world;
-  Collider* prev;
-  Collider* next;
-  void* userdata;
-  uint32_t tag;
-  arr_t(Shape*) shapes;
-  arr_t(Joint*) joints;
-  float friction;
-  float restitution;
-};
-
-struct Shape {
-  uint32_t ref;
-  ShapeType type;
-  dGeomID id;
-  Collider* collider;
-  void* vertices;
-  void* indices;
-  void* userdata;
-  bool sensor;
-};
-
 typedef Shape SphereShape;
 typedef Shape BoxShape;
 typedef Shape CapsuleShape;
 typedef Shape CylinderShape;
 typedef Shape MeshShape;
 
-struct Joint {
-  uint32_t ref;
-  JointType type;
-  dJointID id;
-  void* userdata;
-};
-
 typedef Joint BallJoint;
 typedef Joint DistanceJoint;
 typedef Joint HingeJoint;
@@ -125,6 +83,7 @@ void lovrColliderDestroy(void* ref);
 void lovrColliderDestroyData(Collider* collider);
 void lovrColliderInitInertia(Collider* collider, Shape* shape);
 World* lovrColliderGetWorld(Collider* collider);
+Collider* lovrColliderGetNext(Collider* collider);
 void lovrColliderAddShape(Collider* collider, Shape* shape);
 void lovrColliderRemoveShape(Collider* collider, Shape* shape);
 Shape** lovrColliderGetShapes(Collider* collider, size_t* count);