From 0208883fa1c5be5f92af5566d11002cf65cae3f2 Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Sun, 17 Dec 2023 14:54:38 -0500
Subject: [PATCH] OPL and OPLL vol map

---
 src/engine/platform/fmshared_OPN.h |  2 +-
 src/engine/platform/fmsharedbase.h |  2 +-
 src/engine/platform/opl.cpp        | 15 +++++++++++++++
 src/engine/platform/opl.h          |  1 +
 src/engine/platform/opll.cpp       |  7 +++++++
 src/engine/platform/opll.h         |  1 +
 6 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/engine/platform/fmshared_OPN.h b/src/engine/platform/fmshared_OPN.h
index 3f1267739..e7d06c7f5 100644
--- a/src/engine/platform/fmshared_OPN.h
+++ b/src/engine/platform/fmshared_OPN.h
@@ -191,7 +191,7 @@ class DivPlatformOPN: public DivPlatformFMBase {
       if (ch==adpcmBChanOffs) return vel*255.0;
       if (ch>=adpcmAChanOffs) {
         if (vel==0) return 0;
-        if (vel==127) return 31;
+        if (vel>=1.0) return 31;
         return CLAMP(round(32.0-(56.0-log2(vel*127.0)*8.0)),0,31);
       }
       if (ch>=psgChanOffs) return round(15.0*pow(vel,0.33));
diff --git a/src/engine/platform/fmsharedbase.h b/src/engine/platform/fmsharedbase.h
index 3a12f96e6..f20292a0d 100644
--- a/src/engine/platform/fmsharedbase.h
+++ b/src/engine/platform/fmsharedbase.h
@@ -132,7 +132,7 @@ class DivPlatformFMBase: public DivDispatch {
       // -36: 2: 48
       // -42: 1: 56
       if (vel==0) return 0;
-      if (vel==127) return 127;
+      if (vel>=1.0) return 127;
       return CLAMP(round(128.0-(56.0-log2(vel*127.0)*8.0)),0,127);
     }
 
diff --git a/src/engine/platform/opl.cpp b/src/engine/platform/opl.cpp
index 8eb95fc28..c68271743 100644
--- a/src/engine/platform/opl.cpp
+++ b/src/engine/platform/opl.cpp
@@ -2104,6 +2104,21 @@ DivDispatchOscBuffer* DivPlatformOPL::getOscBuffer(int ch) {
   return oscBuf[ch];
 }
 
+int DivPlatformOPL::mapVelocity(int ch, float vel) {
+  if (ch==adpcmChan) return vel*255.0;
+  // -0.75dB per step
+  // -6: 64: 8
+  // -12: 32: 16
+  // -18: 16: 24
+  // -24: 8: 32
+  // -30: 4: 40
+  // -36: 2: 48
+  // -42: 1: 56
+  if (vel==0) return 0;
+  if (vel>=1.0) return 63;
+  return CLAMP(round(64.0-(56.0-log2(vel*127.0)*8.0)),0,63);
+}
+
 unsigned char* DivPlatformOPL::getRegisterPool() {
   return regPool;
 }
diff --git a/src/engine/platform/opl.h b/src/engine/platform/opl.h
index c4346a21e..bef02db5e 100644
--- a/src/engine/platform/opl.h
+++ b/src/engine/platform/opl.h
@@ -150,6 +150,7 @@ class DivPlatformOPL: public DivDispatch {
     unsigned short getPan(int chan);
     DivChannelPair getPaired(int chan);
     DivDispatchOscBuffer* getOscBuffer(int chan);
+    int mapVelocity(int ch, float vel);
     unsigned char* getRegisterPool();
     int getRegisterPoolSize();
     void reset();
diff --git a/src/engine/platform/opll.cpp b/src/engine/platform/opll.cpp
index 3f1621c02..9228568ef 100644
--- a/src/engine/platform/opll.cpp
+++ b/src/engine/platform/opll.cpp
@@ -962,6 +962,13 @@ DivDispatchOscBuffer* DivPlatformOPLL::getOscBuffer(int ch) {
   return oscBuf[ch];
 }
 
+int DivPlatformOPLL::mapVelocity(int ch, float vel) {
+  // -3dB per step
+  if (vel==0) return 0;
+  if (vel>=1.0) return 15;
+  return CLAMP(round(16.0-(14.0-log2(vel*127.0)*2.0)),0,15);
+}
+
 unsigned char* DivPlatformOPLL::getRegisterPool() {
   return regPool;
 }
diff --git a/src/engine/platform/opll.h b/src/engine/platform/opll.h
index e8bd627a4..70ece9c1e 100644
--- a/src/engine/platform/opll.h
+++ b/src/engine/platform/opll.h
@@ -95,6 +95,7 @@ class DivPlatformOPLL: public DivDispatch {
     void* getChanState(int chan);
     DivMacroInt* getChanMacroInt(int ch);
     DivDispatchOscBuffer* getOscBuffer(int chan);
+    int mapVelocity(int ch, float vel);
     unsigned char* getRegisterPool();
     int getRegisterPoolSize();
     void reset();