From f09e0ba1d9442cd9d29dd7763399b7b16bc50002 Mon Sep 17 00:00:00 2001
From: stele <antoni.sauren@gmail.com>
Date: Mon, 26 Jul 2021 12:25:46 +0200
Subject: [PATCH] Logarytmiczny fade sampli dzwiekow skladanych.

---
 sound.cpp | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/sound.cpp b/sound.cpp
index 62123844..c27571af 100644
--- a/sound.cpp
+++ b/sound.cpp
@@ -809,12 +809,15 @@ sound_source::update_crossfade( sound_handle const Chunk ) {
         // chunks other than the first can have fadein
         auto const fadeinwidth { chunkdata.threshold - chunkdata.fadein };
         if( soundpoint < chunkdata.threshold ) {
-            m_properties.gain *=
+            float lineargain =
                 interpolate(
                     0.f, 1.f,
                     clamp(
                         ( soundpoint - chunkdata.fadein ) / fadeinwidth,
                         0.f, 1.f ) );
+            m_properties.gain *=
+                lineargain /
+                (1 + (1 - lineargain) * (-0.57)); // approximation of logarytmic fade in
             return;
         }
     }
@@ -826,12 +829,14 @@ sound_source::update_crossfade( sound_handle const Chunk ) {
         auto const fadeoutwidth { chunkdata.fadeout - m_soundchunks[ chunkindex + 1 ].second.fadein };
         auto const fadeoutstart { chunkdata.fadeout - fadeoutwidth };
         if( soundpoint > fadeoutstart ) {
-            m_properties.gain *=
+			float lineargain =
                 interpolate(
-                    1.f, 0.f,
+                    0.f, 1.f,
                     clamp(
                         ( soundpoint - fadeoutstart ) / fadeoutwidth,
                         0.f, 1.f ) );
+            m_properties.gain *= (-lineargain + 1) /
+                                 (1 + lineargain * (-0.57)); // approximation of logarytmic fade out
             return;
         }
     }