From 53987f47e29c796d2c9e02889ef03682d66457bd Mon Sep 17 00:00:00 2001
From: Alibek Omarov <a1ba.omarov@gmail.com>
Date: Thu, 30 Mar 2023 04:40:48 +0300
Subject: [PATCH] engine: client: use alternative ease-in ease-out function in
 sound fade

---
 engine/client/s_main.c  |  2 +-
 public/xash3d_mathlib.c | 18 ------------------
 public/xash3d_mathlib.h |  1 -
 3 files changed, 1 insertion(+), 20 deletions(-)

diff --git a/engine/client/s_main.c b/engine/client/s_main.c
index 6002ac32..176af52b 100644
--- a/engine/client/s_main.c
+++ b/engine/client/s_main.c
@@ -159,7 +159,7 @@ void S_UpdateSoundFade( void )
 	}
 
 	// spline it.
-	f = SimpleSpline( f );
+	f = -( cos( M_PI * f ) - 1 ) / 2;
 	f = bound( 0.0f, f, 1.0f );
 
 	soundfade.percent = soundfade.initial_percent * f;
diff --git a/public/xash3d_mathlib.c b/public/xash3d_mathlib.c
index f0e6d52a..c4872e28 100644
--- a/public/xash3d_mathlib.c
+++ b/public/xash3d_mathlib.c
@@ -53,24 +53,6 @@ float anglemod( float a )
 	return a;
 }
 
-/*
-=================
-SimpleSpline
-
-NOTE: ripped from hl2 source
-hermite basis function for smooth interpolation
-Similar to Gain() above, but very cheap to call
-value should be between 0 & 1 inclusive
-=================
-*/
-float SimpleSpline( float value )
-{
-	float	valueSquared = value * value;
-
-	// nice little ease-in, ease-out spline-like curve
-	return (3.0f * valueSquared - 2.0f * valueSquared * value);
-}
-
 word FloatToHalf( float v )
 {
 	unsigned int	i = FloatAsUint( v );
diff --git a/public/xash3d_mathlib.h b/public/xash3d_mathlib.h
index 85cbdb37..1d2e8368 100644
--- a/public/xash3d_mathlib.h
+++ b/public/xash3d_mathlib.h
@@ -177,7 +177,6 @@ float rsqrt( float number );
 float anglemod( float a );
 word FloatToHalf( float v );
 float HalfToFloat( word h );
-float SimpleSpline( float value );
 void RoundUpHullSize( vec3_t size );
 int SignbitsForPlane( const vec3_t normal );
 int PlaneTypeForNormal( const vec3_t normal );