From 38e5e35743f372de3be1324d3adf0473f29d8bd1 Mon Sep 17 00:00:00 2001
From: ekrctb <ekrctb@gmail.com>
Date: Fri, 25 May 2018 01:20:05 +0900
Subject: [PATCH] modify catch hyperdash behavior

---
 osu.Game.Rulesets.Catch/UI/CatcherArea.cs | 62 ++++++++++++++---------
 1 file changed, 38 insertions(+), 24 deletions(-)

diff --git a/osu.Game.Rulesets.Catch/UI/CatcherArea.cs b/osu.Game.Rulesets.Catch/UI/CatcherArea.cs
index 181536a91e..56826d228c 100644
--- a/osu.Game.Rulesets.Catch/UI/CatcherArea.cs
+++ b/osu.Game.Rulesets.Catch/UI/CatcherArea.cs
@@ -248,37 +248,46 @@ namespace osu.Game.Rulesets.Catch.UI
 
                 if (validCatch && fruit.HyperDash)
                 {
-                    HyperDashModifier = Math.Abs(fruit.HyperDashTarget.X - fruit.X) / Math.Abs(fruit.HyperDashTarget.StartTime - fruit.StartTime) / BASE_SPEED;
-                    HyperDashDirection = fruit.HyperDashTarget.X - fruit.X;
+                    var target = fruit.HyperDashTarget;
+                    double timeDifference = target.StartTime - fruit.StartTime;
+                    double positionDifference = target.X * CatchPlayfield.BASE_WIDTH - catcherPosition;
+                    double velocity = positionDifference / Math.Max(1.0, timeDifference - 1000.0 / 60.0);
+
+                    HyperDashing = true;
+                    hyperDashModifier = Math.Abs(velocity);
+                    hyperDashDirection = (int)Math.Sign(velocity);
+                    hyperDashTargetPosition = target.X;
                 }
                 else
-                    HyperDashModifier = 1;
+                {
+                    HyperDashing = false;
+                }
 
                 return validCatch;
             }
 
+            private double hyperDashModifier = 1;
+            private int hyperDashDirection = 0;
+            private float hyperDashTargetPosition;
+            private bool hyperDashing = false;
+
             /// <summary>
             /// Whether we are hypderdashing or not.
             /// </summary>
-            public bool HyperDashing => hyperDashModifier != 1;
-
-            private double hyperDashModifier = 1;
-
-            /// <summary>
-            /// The direction in which hyperdash is allowed. 0 allows both directions.
-            /// </summary>
-            public double HyperDashDirection;
-
-            /// <summary>
-            /// The speed modifier resultant from hyperdash. Will trigger hyperdash when not equal to 1.
-            /// </summary>
-            public double HyperDashModifier
+            protected bool HyperDashing
             {
-                get { return hyperDashModifier; }
+                get => hyperDashing;
                 set
                 {
-                    if (value == hyperDashModifier) return;
-                    hyperDashModifier = value;
+                    if (hyperDashing == value) return;
+
+                    hyperDashing = value;
+
+                    if (!HyperDashing)
+                    {
+                        hyperDashModifier = 1;
+                        hyperDashDirection = 0;
+                    }
 
                     const float transition_length = 180;
 
@@ -290,7 +299,6 @@ namespace osu.Game.Rulesets.Catch.UI
                     }
                     else
                     {
-                        HyperDashDirection = 0;
                         this.FadeColour(Color4.White, transition_length, Easing.OutQuint);
                         this.FadeTo(1, transition_length, Easing.OutQuint);
                     }
@@ -347,12 +355,18 @@ namespace osu.Game.Rulesets.Catch.UI
                 var direction = Math.Sign(currentDirection);
 
                 double dashModifier = Dashing ? 1 : 0.5;
-
-                if (hyperDashModifier != 1 && (HyperDashDirection == 0 || direction == Math.Sign(HyperDashDirection)))
-                    dashModifier = hyperDashModifier;
+                double speed = BASE_SPEED * dashModifier * hyperDashModifier;
 
                 Scale = new Vector2(Math.Abs(Scale.X) * direction, Scale.Y);
-                X = (float)MathHelper.Clamp(X + direction * Clock.ElapsedFrameTime * BASE_SPEED * dashModifier, 0, 1);
+                X = (float)MathHelper.Clamp(X + direction * Clock.ElapsedFrameTime * speed, 0, 1);
+
+                // Correct overshooting.
+                if ((hyperDashDirection > 0 && hyperDashTargetPosition < X) ||
+                    (hyperDashDirection < 0 && hyperDashTargetPosition > X))
+                {
+                    X = hyperDashTargetPosition;
+                    HyperDashing = false;
+                }
             }
 
             /// <summary>