package Terrain
import NoWurst
import Item

constant real		MAX_RANGE	 	= 10.
constant integer 	DUMMY_ITEM_ID 	= 'wolg'
location 			tempLoc 		= Location(0.,0.)
item	   			dItem   		= null
rect	   			find   			= null
item array 			hid
integer				hidMax 			= 0
vec2 				tempPos 		= vec2(0,0)

init
	find = Rect(0., 0., 128., 128.)
	dItem = CreateItem(DUMMY_ITEM_ID, 0, 0)
	SetItemVisible(dItem, false)

/** Returns the (not normalised) terrain-normal at the given point */
public function getTerrainNormal( real x, real y, real sampleRadius) returns vec3
	MoveLocation(tempLoc, x-sampleRadius, y)
	var zx = GetLocationZ(tempLoc)
	MoveLocation(tempLoc, x+sampleRadius, y)
	zx -= GetLocationZ(tempLoc)
	MoveLocation(tempLoc, x, y-sampleRadius)
	var zy = GetLocationZ(tempLoc)
	MoveLocation(tempLoc, x, y+sampleRadius)
	zy -= GetLocationZ(tempLoc)
	let sampleRadius2 = 2*sampleRadius
	return vec3( zx*sampleRadius2, zy*sampleRadius2, sampleRadius2*sampleRadius2 )

public function getTerrainZ(real x, real y) returns real
	MoveLocation( tempLoc, x, y )
	return GetLocationZ( tempLoc )

public function getTerrainZ(vec2 v) returns real
	MoveLocation( tempLoc, v.x, v.y )
	return GetLocationZ( tempLoc )

public function vec2.withTerrainZ() returns vec3
	return vec3(this.x, this.y, getTerrainZ(this.x, this.y))

public function vec2.withTerrainZ(real zoffset) returns vec3
	return vec3(this.x, this.y, getTerrainZ(this.x, this.y) + zoffset)

public function vec3.withTerrainZ() returns vec3
	return vec3(this.x, this.y, getTerrainZ(this.x, this.y))

public function vec3.withTerrainZ(real zoffset) returns vec3
	return vec3(this.x, this.y, getTerrainZ(this.x, this.y) + zoffset)

public function isTerrainDeepWater(real x, real y) returns boolean
	return not IsTerrainPathable(x, y, PATHING_TYPE_FLOATABILITY) and IsTerrainPathable(x, y, PATHING_TYPE_WALKABILITY)

public function isTerrainShallowWater(real x, real y) returns boolean
	return not IsTerrainPathable(x, y, PATHING_TYPE_FLOATABILITY) and not IsTerrainPathable(x, y, PATHING_TYPE_WALKABILITY) and IsTerrainPathable(x, y, PATHING_TYPE_BUILDABILITY)

public function isTerrainLand(real x, real y) returns boolean
	return IsTerrainPathable(x, y, PATHING_TYPE_FLOATABILITY)

public function isTerrainPlatform(real x, real y) returns boolean
	return not IsTerrainPathable(x, y, PATHING_TYPE_FLOATABILITY) and not IsTerrainPathable(x, y, PATHING_TYPE_WALKABILITY) and not IsTerrainPathable(x, y, PATHING_TYPE_BUILDABILITY)

function hideItem()
	if IsItemVisible(GetEnumItem())
		hid[hidMax] = GetEnumItem()
		SetItemVisible(hid[hidMax], false)
		hidMax++

public function isTerrainWalkable(real x, real y) returns boolean
	//Hide any items in the area to avoid conflicts with our item
	MoveRectTo(find, x, y)
	EnumItemsInRect(find ,null, function hideItem)
	//Try to move the test item and get its coords
	SetItemPosition(dItem, x, y) //Unhides the item
	tempPos = dItem.getPos()
	SetItemVisible(dItem, false)//Hide it again
	//Unhide any items hidden at the start
	while hidMax > 0
		hidMax--
		SetItemVisible(hid[hidMax], true)
		hid[hidMax] = null
	//Return walkability
	return (tempPos.x-x)*(tempPos.x-x)+(tempPos.y-y)*(tempPos.y-y) <= MAX_RANGE*MAX_RANGE and not IsTerrainPathable(x, y, PATHING_TYPE_WALKABILITY)