From 482f5de0fe3c5f2e28241f5584e6a40990c769b2 Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Sun, 14 Jul 2024 19:58:33 -0500
Subject: [PATCH] prepare to add function for mapping vol to percent

---
 src/engine/dispatch.h            | 8 ++++++++
 src/engine/platform/abstract.cpp | 5 +++++
 2 files changed, 13 insertions(+)

diff --git a/src/engine/dispatch.h b/src/engine/dispatch.h
index 6757fe1e8..aa355f488 100644
--- a/src/engine/dispatch.h
+++ b/src/engine/dispatch.h
@@ -681,6 +681,14 @@ class DivDispatch {
      */
     virtual int mapVelocity(int ch, float vel);
 
+    /**
+     * map chip volume to gain.
+     * @param ch the chip channel. -1 means N/A.
+     * @param vol input volume.
+     * @return output gain fron 0.0 to 1.0.
+     */
+    virtual float getGain(int ch, int vol);
+
     /**
      * get the lowest note in a portamento.
      * @param ch the channel in question.
diff --git a/src/engine/platform/abstract.cpp b/src/engine/platform/abstract.cpp
index 14370f297..441ec1bff 100644
--- a/src/engine/platform/abstract.cpp
+++ b/src/engine/platform/abstract.cpp
@@ -107,6 +107,11 @@ int DivDispatch::mapVelocity(int ch, float vel) {
   return round(vel*volMax);
 }
 
+float DivDispatch::getGain(int ch, int vol) {
+  const float volMax=MAX(1,dispatch(DivCommand(DIV_CMD_GET_VOLMAX,MAX(ch,0))));
+  return (float)vol/volMax;
+}
+
 int DivDispatch::getPortaFloor(int ch) {
   return 0x00;
 }