0022-Make-the-angular-stream-interp-chose-the-best-initia.patch

From 01e0ffb667c900e634602bbd450d63130b504a61 Mon Sep 17 00:00:00 2001
From: Ivan Molodetskikh <yalterz@gmail.com>
Date: Sat, 31 Dec 2016 13:49:38 +0300
Subject: [PATCH 22/28] Make the angular stream interp chose the best initial
 direction

---
 .../Interpolators/StreamAngularInterpolator.cs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/osu!/Helpers/Interpolators/StreamAngularInterpolator.cs b/osu!/Helpers/Interpolators/StreamAngularInterpolator.cs
index d1a14ed..1802cba 100644
--- a/osu!/Helpers/Interpolators/StreamAngularInterpolator.cs
+++ b/osu!/Helpers/Interpolators/StreamAngularInterpolator.cs
@@ -35,6 +35,18 @@ namespace osu.Helpers.Interpolators
             var pos_difference = Points[1].pos - Points[0].pos;
             var pos_difference_rotated = new Vector2(-pos_difference.Y, pos_difference.X);
 
+            // Pick the derivative direction so it goes outwards.
+            if (Points.Count > 2)
+            {
+                var pos_difference_rotated_normalized = pos_difference_rotated;
+                pos_difference_rotated_normalized.Normalize();
+                var next_pos_difference = Points[2].pos - Points[1].pos;
+                next_pos_difference.Normalize();
+
+                if (Vector2.Dot(pos_difference_rotated_normalized, next_pos_difference) > 0.99)
+                    pos_difference_rotated = -pos_difference_rotated;
+            }
+
             // The first one is 45 degrees.
             var derivative = pos_difference + pos_difference_rotated;
             derivative.Normalize();
@@ -46,6 +58,9 @@ namespace osu.Helpers.Interpolators
                 pos_difference_rotated = new Vector2(-pos_difference.Y, pos_difference.X);
                 pos_difference_rotated /= 2;
 
+                if (Vector2.Dot(derivative, pos_difference) < 0)
+                    derivative = -derivative;
+
                 if (Vector2.Dot(derivative, pos_difference_rotated) < 0)
                     pos_difference_rotated = -pos_difference_rotated;
 
@@ -102,6 +117,9 @@ namespace osu.Helpers.Interpolators
             var pos_difference_rotated = new Vector2(-pos_difference.Y, pos_difference.X);
             pos_difference_rotated /= 2;
 
+            if (Vector2.Dot(derivative, pos_difference) < 0)
+                derivative = -derivative;
+
             if (Vector2.Dot(derivative, pos_difference_rotated) < 0)
                 pos_difference_rotated = -pos_difference_rotated;
 
-- 
2.19.1