actually implement this function

src/physics.rs

@@ -491,17 +491,23 @@ impl MoveState{
 				//clip according to contacts
 				touching.constrain_acceleration(models,hitbox_mesh,&mut a);
 				//something
+				set_acceleration(body,touching,models,hitbox_mesh,a);
 			},
 			MoveState::Water=>(),
 			MoveState::Fly=>{
 				//set velocity according to current control state
+				let mut v=style.get_propulsion_control_dir(camera,input_state.controls)*80;
 				//clip velocity according to current touching state
+				touching.constrain_velocity(models,hitbox_mesh,&mut v);
 				//apply to body
+				set_velocity(body,touching,models,hitbox_mesh,v);
 			},
 			MoveState::Walk(walk_state)
 			|MoveState::Ladder(walk_state)
 			=>{
 				//accelerate towards walk target or do nothing
+				let a=walk_state.target.acceleration();
+				set_acceleration(body,touching,models,hitbox_mesh,a);
 			},
 		}
 	}