------------------------------------------------------------------------


local Input = {} do
	local thumbstickCurve do
		local K_CURVATURE = 2.0
		local K_DEADZONE = 0.15

		local function fCurve(x)
			return (exp(K_CURVATURE*x) - 1)/(exp(K_CURVATURE) - 1)
		end

		local function fDeadzone(x)
			return fCurve((x - K_DEADZONE)/(1 - K_DEADZONE))
		end

		function thumbstickCurve(x)
			return sign(x)*clamp(fDeadzone(abs(x)), 0, 1)
		end
	end

	local gamepad = {
		ButtonX = 0,
		ButtonY = 0,
		DPadDown = 0,
		DPadUp = 0,
		ButtonL2 = 0,
		ButtonR2 = 0,
		Thumbstick1 = Vector2.new(),
		Thumbstick2 = Vector2.new(),
	}

	local keyboard = {
		W = 0,
		A = 0,
		S = 0,
		D = 0,
		E = 0,
		Q = 0,
		U = 0,
		H = 0,
		J = 0,
		K = 0,
		I = 0,
		Y = 0,
		Up = 0,
		Down = 0,
		LeftShift = 0,
		RightShift = 0,
	}

	local mouse = {
		Delta = Vector2.new(),
		MouseWheel = 0,
	}

	local NAV_GAMEPAD_SPEED  = Vector3.new(1, 1, 1)
	local NAV_KEYBOARD_SPEED = Vector3.new(1, 1, 1)
	local PAN_MOUSE_SPEED    = Vector2.new(1, 1)*(pi/64)
	local PAN_GAMEPAD_SPEED  = Vector2.new(1, 1)*(pi/8)
	local FOV_WHEEL_SPEED    = 1.0
	local FOV_GAMEPAD_SPEED  = 0.25
	local NAV_ADJ_SPEED      = 0.75
	local NAV_SHIFT_MUL      = 0.25

	local navSpeed = 1

	function Input.Vel(dt)
		navSpeed = clamp(navSpeed + dt*(keyboard.Up - keyboard.Down)*NAV_ADJ_SPEED, 0.01, 4)

		local kGamepad = Vector3.new(
			thumbstickCurve(gamepad.Thumbstick1.X),
			thumbstickCurve(gamepad.ButtonR2) - thumbstickCurve(gamepad.ButtonL2),
			thumbstickCurve(-gamepad.Thumbstick1.Y)
		)*NAV_GAMEPAD_SPEED

		local kKeyboard = Vector3.new(
			keyboard.D - keyboard.A + keyboard.K - keyboard.H,
			keyboard.E - keyboard.Q + keyboard.I - keyboard.Y,
			keyboard.S - keyboard.W + keyboard.J - keyboard.U
		)*NAV_KEYBOARD_SPEED

		local shift = UserInputService:IsKeyDown(Enum.KeyCode.LeftShift) or UserInputService:IsKeyDown(Enum.KeyCode.RightShift)

		return (kGamepad + kKeyboard)*(navSpeed*(shift and NAV_SHIFT_MUL or 1))
	end

	function Input.Pan(dt)
		local kGamepad = Vector2.new(
			thumbstickCurve(gamepad.Thumbstick2.Y),
			thumbstickCurve(-gamepad.Thumbstick2.X)
		)*PAN_GAMEPAD_SPEED
		local kMouse = mouse.Delta*PAN_MOUSE_SPEED
		mouse.Delta = Vector2.new()
		return kGamepad + kMouse
	end

	function Input.Fov(dt)
		local kGamepad = (gamepad.ButtonX - gamepad.ButtonY)*FOV_GAMEPAD_SPEED
		local kMouse = mouse.MouseWheel*FOV_WHEEL_SPEED
		mouse.MouseWheel = 0
		return kGamepad + kMouse
	end

	do
		local function Keypress(action, state, input)
			keyboard[input.KeyCode.Name] = state == Enum.UserInputState.Begin and 1 or 0
			return Enum.ContextActionResult.Sink
		end

		local function GpButton(action, state, input)
			gamepad[input.KeyCode.Name] = state == Enum.UserInputState.Begin and 1 or 0
			return Enum.ContextActionResult.Sink
		end

		local function MousePan(action, state, input)
			local delta = input.Delta
			mouse.Delta = Vector2.new(-delta.y, -delta.x)
			return Enum.ContextActionResult.Sink
		end

		local function Thumb(action, state, input)
			gamepad[input.KeyCode.Name] = input.Position
			return Enum.ContextActionResult.Sink
		end

		local function Trigger(action, state, input)
			gamepad[input.KeyCode.Name] = input.Position.z
			return Enum.ContextActionResult.Sink
		end

		local function MouseWheel(action, state, input)
			mouse[input.UserInputType.Name] = -input.Position.z
			return Enum.ContextActionResult.Sink
		end

		local function Zero(t)
			for k, v in pairs(t) do
				t[k] = v*0
			end
		end

		function Input.StartCapture()
			ContextActionService:BindActionAtPriority("FreecamKeyboard", Keypress, false, INPUT_PRIORITY,
				Enum.KeyCode.W, Enum.KeyCode.U,
				Enum.KeyCode.A, Enum.KeyCode.H,
				Enum.KeyCode.S, Enum.KeyCode.J,
				Enum.KeyCode.D, Enum.KeyCode.K,
				Enum.KeyCode.E, Enum.KeyCode.I,
				Enum.KeyCode.Q, Enum.KeyCode.Y,
				Enum.KeyCode.Up, Enum.KeyCode.Down
			)
			ContextActionService:BindActionAtPriority("FreecamMousePan",          MousePan,   false, INPUT_PRIORITY, Enum.UserInputType.MouseMovement)
			ContextActionService:BindActionAtPriority("FreecamMouseWheel",        MouseWheel, false, INPUT_PRIORITY, Enum.UserInputType.MouseWheel)
			ContextActionService:BindActionAtPriority("FreecamGamepadButton",     GpButton,   false, INPUT_PRIORITY, Enum.KeyCode.ButtonX, Enum.KeyCode.ButtonY)
			ContextActionService:BindActionAtPriority("FreecamGamepadTrigger",    Trigger,    false, INPUT_PRIORITY, Enum.KeyCode.ButtonR2, Enum.KeyCode.ButtonL2)
			ContextActionService:BindActionAtPriority("FreecamGamepadThumbstick", Thumb,      false, INPUT_PRIORITY, Enum.KeyCode.Thumbstick1, Enum.KeyCode.Thumbstick2)
		end

		function Input.StopCapture()
			navSpeed = 1
			Zero(gamepad)
			Zero(keyboard)
			Zero(mouse)
			ContextActionService:UnbindAction("FreecamKeyboard")
			ContextActionService:UnbindAction("FreecamMousePan")
			ContextActionService:UnbindAction("FreecamMouseWheel")
			ContextActionService:UnbindAction("FreecamGamepadButton")
			ContextActionService:UnbindAction("FreecamGamepadTrigger")
			ContextActionService:UnbindAction("FreecamGamepadThumbstick")
		end
	end
end

local function GetFocusDistance(cameraFrame)
	local znear = 0.1
	local viewport = Camera.ViewportSize
	local projy = 2*tan(cameraFov/2)
	local projx = viewport.x/viewport.y*projy
	local fx = cameraFrame.rightVector
	local fy = cameraFrame.upVector
	local fz = cameraFrame.lookVector

	local minVect = Vector3.new()
	local minDist = 512

	for x = 0, 1, 0.5 do
		for y = 0, 1, 0.5 do
			local cx = (x - 0.5)*projx
			local cy = (y - 0.5)*projy
			local offset = fx*cx - fy*cy + fz
			local origin = cameraFrame.p + offset*znear
			local _, hit = Workspace:FindPartOnRay(Ray.new(origin, offset.unit*minDist))
			local dist = (hit - origin).Magnitude
			if minDist > dist then
				minDist = dist
				minVect = offset.unit
			end
		end
	end

	return fz:Dot(minVect)*minDist
end
