a lua camera

camera.lua

--
--
--
--
--

local camera = {
	TWEEN = 1,
	SET = 2,

	x = 0,
	y = 0,

	world = {
		top = 0,
		left = 0,
		right = 640,
		bottom = 360
	},

	start = {
		x = 0,
		y = 0
	},
	target = {
		x = 0,
		y = 0
	},
	speed = {
		passive = 2,
		active = 5,
	},
	mode = 1,
	tweenTime = 0,

	offset = {
		x = 0,
		y = 0
	},
	shaking = false,
	length = 0,
	intensity = 0,

	following = false,
}

function camera:shake(length, intensity)
	self.shaking = true

	self.intensity = intensity and intensity or 5
	self.length = length and length or 0.2
end

function camera:update(dt, speed)
	local horizontal, vertical = 0, 0

	local following = game:get(self.following)

	if horizontal ~= 0 or vertical ~= 0 then
		self.target.x = self.target.x - (horizontal * self.speed.active)
		self.target.y = self.target.y - (vertical * self.speed.active)
	elseif following then
		self:setPosition(following.x, following.y)
	end

	if self.mode == self.TWEEN then
		self.tweenTime = self.tweenTime + (dt * speed * self.speed.passive)
		self.x = math.lerp(self.start.x, self.target.x, self.tweenTime)
		self.y = math.lerp(self.start.y, self.target.y, self.tweenTime)

		if self.tweenTime > 1 then
			self.x = self.target.x
			self.y = self.target.y

			self.target.x = self.x
			self.target.y = self.y
		end
	elseif self.mode == self.SET then
		self.x = self.target.x
		self.y = self.target.y
	end
end

function camera:follow(entity)
	self.following = entity
end

function camera:unfollow()
	self.following = false
end

function camera:setPosition(x, y, mode, speed)
	if speed then
		self.speed = speed
	end

	if mode then
		self.mode = mode
	end

	self.start.x = self.x
	self.start.y = self.y

	self.target.x = -x + math.floor(game.width / 2)
	self.target.y = -y + math.floor(game.height / 2)
	self.tweenTime = 0
end

return camera