From 372ba7666304805abe8641487c97899f9bdd97af Mon Sep 17 00:00:00 2001
From: Tokage <tokage.it.lab@gmail.com>
Date: Sun, 25 Apr 2021 05:47:03 +0900
Subject: implement ping-pong loop in animation

Co-authored-by: Chaosus <chaosus89@gmail.com>
---
 modules/mono/glue/GodotSharp/GodotSharp/Core/Mathf.cs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

(limited to 'modules/mono/glue/GodotSharp')

diff --git a/modules/mono/glue/GodotSharp/GodotSharp/Core/Mathf.cs b/modules/mono/glue/GodotSharp/GodotSharp/Core/Mathf.cs
index 6f7fac7429..df0dcdb1bb 100644
--- a/modules/mono/glue/GodotSharp/GodotSharp/Core/Mathf.cs
+++ b/modules/mono/glue/GodotSharp/GodotSharp/Core/Mathf.cs
@@ -693,5 +693,23 @@ namespace Godot
             }
             return min + ((((value - min) % range) + range) % range);
         }
+
+        private static real_t Fract(real_t value)
+        {
+            return value - (real_t)Math.Floor(value);
+        }
+
+        /// <summary>
+        /// Returns the [code]value[/code] wrapped between [code]0[/code] and the [code]length[/code].
+        /// If the limit is reached, the next value the function returned is decreased to the [code]0[/code] side or increased to the [code]length[/code] side (like a triangle wave).
+        /// If [code]length[/code] is less than zero, it becomes positive.
+        /// </summary>
+        /// <param name="value">The value to pingpong.</param>
+        /// <param name="length">The maximum value of the function.</param>
+        /// <returns>The ping-ponged value.</returns>
+        public static real_t PingPong(real_t value, real_t length)
+        {
+            return (length != 0.0) ? Math.Abs(Mathf.Fract((value - length) / (length * 2.0)) * length * 2.0 - length) : 0.0;
+        }
     }
 }
-- 
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