Made the frame rate independent lerp backwards compatible

britzl · Aug 11, 2018 · 8fde37e · 8fde37e
1 parent 9dd07be
commit 8fde37e
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Showing 3 changed files with 12 additions and 12 deletions.
diff --git a/example/camera_controls.gui_script b/example/camera_controls.gui_script
@@ -41,7 +41,7 @@ function on_input(self, action_id, action)
 			return true
 		elseif gui.pick_node(gui.get_node("follow_basic/button"), action.x, action.y) then
 			self.follow = true
-			self.lerp = 0
+			self.lerp = 1
 			return true
 		elseif gui.pick_node(gui.get_node("follow_lerp/button"), action.x, action.y) then
 			self.follow = true
@@ -100,7 +100,6 @@ end
 function on_message(self, message_id, message, sender)
 	if message_id == hash("camera_offset") then
 		self.camera_offset = message.offset
-		print(self.camera_offset)
 	end
 end
 

diff --git a/example/player.script b/example/player.script
@@ -2,10 +2,6 @@ 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()
@@ -21,17 +17,17 @@ 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)
+		self.camera_offset.y = vmath.lerp(0.05, 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)
+		self.camera_offset.y = vmath.lerp(0.05, 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)
+		self.camera_offset.x = vmath.lerp(0.05, 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)
+		self.camera_offset.x = vmath.lerp(0.05, self.camera_offset.x, 500)
 	end
 
 	msg.post("controls", "camera_offset", { offset = self.camera_offset})

diff --git a/orthographic/camera.lua b/orthographic/camera.lua
@@ -13,6 +13,7 @@ M.PROJECTOR.FIXED_ZOOM = hash("FIXED_ZOOM")
 
 local DISPLAY_WIDTH = tonumber(sys.get_config("display.width")) or 960
 local DISPLAY_HEIGHT = tonumber(sys.get_config("display.height")) or 640
+local UPDATE_FREQUENCY = tonumber(sys.get_config("display.update_frequency")) or 60
 
 local WINDOW_WIDTH = DISPLAY_WIDTH
 local WINDOW_HEIGHT = DISPLAY_HEIGHT
@@ -62,12 +63,16 @@ 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/
+-- return vmath.lerp(1 - math.pow(t, dt), v1, v2)
+-- https://www.gamasutra.com/blogs/ScottLembcke/20180404/316046/Improved_Lerp_Smoothing.php
 local function lerp_with_dt(t, dt, v1, v2)
-	return vmath.lerp(1 - math.pow(t, dt), v1, v2)
+	local rate = UPDATE_FREQUENCY * math.log10(1 - t)
+	return vmath.lerp(1 - math.pow(10, rate * dt), v1, v2)
+	--return vmath.lerp(t, v1, v2)
 end
 
-
 --- Add a custom projector
 -- @param projector_id Unique id of the projector (hash)
 -- @param projector_fn The function to call when the projection matrix needs to be calculated