Attempt to fix the junk non-GM instruments appear when loading custom bank

Author: Wohlstand

README.md

@@ -184,7 +184,7 @@ To build that example you will need to have installed SDL2 library.
 * Add support of MIDI Format 2 files
 
 # Changelog
-## 1.5.2   dev
+## 1.6.2   dev
  * Fixed the random stuck problem in the DOS version of the ADLMIDI player.
  * Added support for HMI and HMP files!
  * Added support for in-track (local) loops.
@@ -196,6 +196,7 @@ To build that example you will need to have installed SDL2 library.
  * Added Jammie O'Connel's FM Synth volume model.
  * Added support for DMX OP2's Fixed Note feature for melodic instruments.
  * Fixed the unexpected playback distortion while playing IMF/CMF/KLM files using DosBox OPL3 emulator.
+ * Fixed unexpected non-GM instruments from embedded bank appears when loading custom GM-only bank.
 
 ## 1.6.1   2025-09-22
  * WinMM: Fixed random crash on waveOutOpen initialisation because of incorrect initialisation structure usage.

src/adlmidi_load.cpp

@@ -116,8 +116,6 @@ bool MIDIplay::LoadBank(FileAndMemReader &fr)
 
     Synth &synth = *m_synth;
 
-    synth.setEmbeddedBank(m_setup.bankId);
-
     synth.m_insBankSetup.scaleModulators = false;
     synth.m_insBankSetup.deepTremolo = (wopl->opl_flags & WOPL_FLAG_DEEP_TREMOLO) != 0;
     synth.m_insBankSetup.deepVibrato = (wopl->opl_flags & WOPL_FLAG_DEEP_VIBRATO) != 0;
@@ -130,6 +128,8 @@ bool MIDIplay::LoadBank(FileAndMemReader &fr)
     uint16_t slots_counts[2] = {wopl->banks_count_melodic, wopl->banks_count_percussion};
     WOPLBank *slots_src_ins[2] = { wopl->banks_melodic, wopl->banks_percussive };
 
+    synth.m_insBanks.clear();
+
     for(size_t ss = 0; ss < 2; ss++)
     {
         for(size_t i = 0; i < slots_counts[ss]; i++)
@@ -148,6 +148,8 @@ bool MIDIplay::LoadBank(FileAndMemReader &fr)
         }
     }
 
+    synth.clearInstCache();
+
     synth.m_embeddedBank = Synth::CustomBankTag; // Use dynamic banks!
     //Percussion offset is count of instruments multipled to count of melodic banks
     applySetup();

src/adlmidi_opl3.cpp

@@ -471,14 +471,19 @@ void OPL3::setEmbeddedBank(uint32_t bank)
     }
 
     // Reset caches once bank is changed
-    adl_fill_vector<const OplTimbre*>(m_insCache, &c_defaultInsCache);
-    adl_fill_vector<bool>(m_insCacheModified, false);
+    clearInstCache();
 
 #else
     ADL_UNUSED(bank);
 #endif
 }
 
+void OPL3::clearInstCache()
+{
+    adl_fill_vector<const OplTimbre*>(m_insCache, &c_defaultInsCache);
+    adl_fill_vector<bool>(m_insCacheModified, false);
+}
+
 void OPL3::writeReg(size_t chip, uint16_t address, uint8_t value)
 {
     m_chips[chip]->writeReg(address, value);

src/adlmidi_opl3.hpp

@@ -309,6 +309,11 @@ class OPL3
      */
     void setEmbeddedBank(uint32_t bank);
 
+    /**
+     * @brief Clears the selected instruments cache
+     */
+    void clearInstCache();
+
     /**
      * @brief Write data to OPL3 chip register
      * @param chip Index of emulated chip. In hardware OPL3 builds, this parameter is ignored