package PhysicsEntity
import public Entity
import Heightmap

public constant MAX_MASS = 250
//Module for Physical Simulation
public module PhysicsModule
	real terrainZ = 0.
	// Physical factors

	// The higher the more slide. Should be < 1.
	real surfaceFriction = 0.9
	// Defines the bounciness
	real restitution = 0.9
	// The density of the object

	function onGroundHit()

	function onEscapeGround()

	// This function should be called every ANIMATION_PERIOD tick if the Entity is active
	function physicsUpdate(Entity e)
		if not e.done and e.active
			let pos = e.getPos()
			if DYNAMIC_Z
				terrainZ = pos.getHeightMap()
			if pos.z > terrainZ
				inAir(e)
			else
				onGround(e)

	// When the Entity is on or near the ground
	function onGround(Entity e)
		e.scaleVel(surfaceFriction)
		if e.flying
			e.flying = false
			onGroundHit()


	function inAir(Entity e)
		if not e.flying
			e.flying = true
			onEscapeGround()