Added follow offset

README.md

@@ -49,6 +49,9 @@ Id of the game object to follow. See ```camera.follow()``` for details.
 #### follow_lerp (number)
 Amount of lerp when following a target. See ```camera.follow()``` for details.
 
+#### follow_offset (vector3)
+Camera offset from the position of the followed target. See ```camera.follow()``` for details.
+
 #### bounds_left (number), bounds_right (number), bounds_top (number), bounds_bottom (number)
 The camera bounds. See ```camera.bounds()``` for details.
 
@@ -169,6 +172,7 @@ Follow a game object.
 * ```camera_id``` (hash|url)
 * ```target``` (hash|url) - Game object to follow
 * ```lerp``` (number) - Lerp from current position to target position with ```lerp``` as t. Optional.
+* ```offset``` (vector3) - Camera offset from target position. Optional.
 
 ### camera.unfollow(camera_id)
 Stop following a game object.

example/player.script

@@ -2,9 +2,14 @@ local camera = require "orthographic.camera"
 
 local SPEED = 400
 
+local function lerp(t, dt, from, to)
+	return vmath.lerp(1 - math.pow(t, dt), from, to)
+end
+
 function init(self)
 	self.input = {}
 	self.crosshair = vmath.vector3()
+	self.camera_offset = vmath.vector3()
 end
 
 function update(self, dt)
@@ -16,14 +21,19 @@ function update(self, dt)
 	local pos = go.get_position()
 	if self.input[hash("up")] then
 		pos.y = pos.y + SPEED * dt
+		self.camera_offset.y = lerp(0.25, dt, self.camera_offset.y, 300)
 	elseif self.input[hash("down")] then
 		pos.y = pos.y - SPEED * dt
+		self.camera_offset.y = lerp(0.25, dt, self.camera_offset.y, -300)
 	end
 	if self.input[hash("left")] then
 		pos.x = pos.x - SPEED * dt
+		self.camera_offset.x = lerp(0.25, dt, self.camera_offset.x, -500)
 	elseif self.input[hash("right")] then
 		pos.x = pos.x + SPEED * dt
+		self.camera_offset.x = lerp(0.25, dt, self.camera_offset.x, 500)
 	end
+	camera.follow(go.get_id("camera"), go.get_id(), 0.1, self.camera_offset)
 	go.set_position(pos)
 end
 

orthographic/camera.lua

@@ -62,6 +62,11 @@ projectors[M.PROJECTOR.FIXED_ZOOM] = function(camera_id, near_z, far_z, zoom)
 	return vmath.matrix4_orthographic(xoffset, xoffset + projected_width, yoffset, yoffset + projected_height, near_z, far_z)
 end
 
+-- http://www.rorydriscoll.com/2016/03/07/frame-rate-independent-damping-using-lerp/
+local function lerp_with_dt(t, dt, v1, v2)
+	return vmath.lerp(1 - math.pow(t, dt), v1, v2)
+end
+
 
 --- Add a custom projector
 -- @param projector_id Unique id of the projector (hash)
@@ -160,7 +165,6 @@ function M.final(camera_id)
 	cameras[camera_id] = nil
 end
 
-
 --- Update a camera
 -- When calling this function a number of things happen:
 -- * Follow target game object (if any)
@@ -183,8 +187,8 @@ function M.update(camera_id, dt)
 	local follow_enabled = go.get(camera.url, "follow")
 	if follow_enabled then
 		local follow = go.get(camera.url, "follow_target")
-		local target_pos = go.get_position(follow)
-		local target_world_pos = go.get_world_position(follow)
+		local follow_offset = go.get(camera.url, "follow_offset")
+		local target_world_pos = go.get_world_position(follow) + follow_offset
 		local new_pos
 		local deadzone_top = go.get(camera.url, "deadzone_top")
 		local deadzone_left = go.get(camera.url, "deadzone_left")
@@ -211,7 +215,7 @@ function M.update(camera_id, dt)
 		end
 		new_pos.z = camera_world_pos.z
 		local follow_lerp = go.get(camera.url, "follow_lerp")
-		camera_world_pos = vmath.lerp(follow_lerp, camera_world_pos, new_pos)
+		camera_world_pos = lerp_with_dt(follow_lerp, dt, camera_world_pos, new_pos)
 		camera_world_pos.z = new_pos.z
 	end
 
@@ -256,8 +260,7 @@ function M.update(camera_id, dt)
 			camera.recoil = nil
 		else
 			local t = camera.recoil.time_left / camera.recoil.duration
-			camera.recoil.offset.x = vmath.lerp(t, 0, camera.recoil.offset.x)
-			camera.recoil.offset.y = vmath.lerp(t, 0, camera.recoil.offset.y)
+			camera.recoil.offset = vmath.lerp(t, VECTOR3_ZERO, camera.recoil.offset)
 		end
 	end
 
@@ -281,10 +284,11 @@ end
 -- @param camera_id
 -- @param target The game object to follow
 -- @param lerp Optional lerp to smoothly move the camera towards the target
-function M.follow(camera_id, target, lerp)
+-- @param offset Optional offset from target position
+function M.follow(camera_id, target, lerp, offset)
 	assert(camera_id, "You must provide a camera id")
 	assert(target, "You must provide a target")
-	msg.post(cameras[camera_id].url, "follow", { target = target, lerp = lerp })
+	msg.post(cameras[camera_id].url, "follow", { target = target, lerp = lerp, offset = offset })
 end
 
 

orthographic/camera.script

@@ -9,6 +9,7 @@ go.property("offset_gui", false)
 go.property("follow", false)
 go.property("follow_target", hash(""))
 go.property("follow_lerp", 0.5)
+go.property("follow_offset", vmath.vector3(0, 0, 0))
 
 go.property("bounds_left", 0)
 go.property("bounds_bottom", 0)
@@ -81,6 +82,7 @@ function on_message(self, message_id, message, sender)
 		self.follow = true
 		self.follow_target = type(message.target) == "string" and hash(message.target) or message.target
 		self.follow_lerp = message.lerp or 1
+		self.follow_offset = message.offset or vmath.vector3()
 	elseif message_id == DEADZONE then
 		self.deadzone_right = message.right or 0
 		self.deadzone_top = message.top or 0