--- /dev/null
+#ifndef _PHYSICS_H_
+#define _PHYSICS_H_
+
+#include <stdbool.h>
+#include "common/terrain.h"
+#include "types.h"
+
+bool physics_ground(Terrain *terrain, bool collide, aabb3f32 box, v3f64 *pos, v3f64 *vel);
+bool physics_step (Terrain *terrain, bool collide, aabb3f32 box, v3f64 *pos, v3f64 *vel, v3f64 *acc, f64 t);
+
+#endif // _PHYSICS_H_