diff --git a/src/body.rs b/src/body.rs
index 100b46ee..ff17114b 100644
--- a/src/body.rs
+++ b/src/body.rs
@@ -1,7 +1,7 @@
 pub struct Body {
 	pub position: glam::Vec3,//I64 where 2^32 = 1 u
 	pub velocity: glam::Vec3,//I64 where 2^32 = 1 u/s
-	pub time: i64,//nanoseconds x xxxxD!
+	pub time: TIMESTAMP,//nanoseconds x xxxxD!
 }
 
 pub struct PhysicsState {
@@ -14,9 +14,12 @@ pub struct PhysicsState {
 	pub grounded: bool,
 	pub walkspeed: f32,
 }
+
+pub type TIMESTAMP = i64;
+
 const CONTROL_JUMP:u32 = 0b01000000;//temp
 impl PhysicsState {
-	pub fn run(&mut self, time: i64, control_dir: glam::Vec3, controls: u32){
+	pub fn run(&mut self, time: TIMESTAMP, control_dir: glam::Vec3, controls: u32){
 		let target_tick = (time/10_000_000) as u32;//100t
 		//the game code can run for 1 month before running out of ticks
 		for tick in self.tick+1..=target_tick {
@@ -49,10 +52,10 @@ impl PhysicsState {
 		}
 		self.tick=target_tick;
 
-		self.body.time=target_tick as i64*10_000_000;
+		self.body.time=target_tick as TIMESTAMP*10_000_000;
 	}
 
-	pub fn extrapolate_position(&self, time: i64) -> glam::Vec3 {
+	pub fn extrapolate_position(&self, time: TIMESTAMP) -> glam::Vec3 {
 		let dt=(time-self.body.time) as f64/1_000_000_000f64;
 		self.body.position+self.body.velocity*(dt as f32)+self.gravity*((0.5*dt*dt) as f32)
 	}