major gfx refactor

pxl8d/src/sim.rs

@@ -28,6 +28,20 @@ impl Default for Entity {
     }
 }
 
+impl Clone for Entity {
+    fn clone(&self) -> Self {
+        Self {
+            pos: self.pos,
+            vel: self.vel,
+            yaw: self.yaw,
+            pitch: self.pitch,
+            flags: self.flags,
+            kind: self.kind,
+            _pad: self._pad,
+        }
+    }
+}
+
 pub struct Simulation {
     pub entities: Vec<Entity>,
     pub free_list: Vec<u32>,