-Added lookat/get_angle_to functions in 2D, and a demo, closes #1843

-Added get_viewport().get_mouse_pos() to replace Input.get_mouse_pos(), closes #1838

2d/lookat/engine.cfg

@@ -0,0 +1,4 @@
+[application]
+
+name="Look At Pointer"
+main_scene="res://lookat.scn"

2d/lookat/lookat.gd

@@ -0,0 +1,43 @@
+
+extends Sprite
+
+# member variables here, example:
+# var a=2
+# var b="textvar"
+
+const MODE_DIRECT=0
+const MODE_CONSTANT=1
+const MODE_SMOOTH=2
+
+const ROTATION_SPEED = 1
+const SMOOTH_SPEED = 2.0
+
+export(int,"Direct","Constant","Smooth") var mode=MODE_DIRECT
+
+func _process(delta):
+	var mpos = get_viewport().get_mouse_pos()
+	
+	if (mode==MODE_DIRECT):
+	
+		look_at(mpos)
+		
+	elif (mode==MODE_CONSTANT):
+	
+		var ang = get_angle_to(mpos)
+		var s = sign(ang)
+		ang=abs(ang)
+		
+		rotate( min(ang,ROTATION_SPEED*delta)*s )
+		
+	elif (mode==MODE_SMOOTH):
+	
+		var ang = get_angle_to(mpos)		
+		
+		rotate( ang*delta*SMOOTH_SPEED )
+
+func _ready():
+	# Initialization here
+	set_process(true)
+	pass
+
+