Merge pull request #837 from edge-classic/decoder-updates

Update decoders; restore (optional) OPL MIDI support

CMakeLists.txt

@@ -35,6 +35,7 @@ option(EDGE_IMF_SUPPORT "Enable support for IMF music format" ON)
 option(EDGE_MP3_SUPPORT "Enable support for MP3 music format" ON)
 option(EDGE_MUS_SUPPORT "Enable support for MUS MIDI format" ON)
 option(EDGE_OGG_SUPPORT "Enable support for OGG music format" ON)
+option(EDGE_OPL_SUPPORT "Enable support for MIDI playback via OPL emulation" ON)
 option(EDGE_SID_SUPPORT "Enable support for C64 SID music" ON)
 option(EDGE_TRACKER_SUPPORT "Enable support for Tracker music (MOD/XM/S3M/IT)" ON)
 option(EDGE_XMI_SUPPORT "Enable support for XMI MIDI format" ON)
@@ -204,6 +205,10 @@ if (EDGE_OGG_SUPPORT)
   add_definitions(-DEDGE_OGG_SUPPORT)
 endif()
 
+if (EDGE_OPL_SUPPORT)
+  add_definitions(-DEDGE_OPL_SUPPORT)
+endif()
+
 if (EDGE_SID_SUPPORT)
   add_definitions(-DEDGE_SID_SUPPORT)
 endif()

docs/licenses/License Attribution.txt

@@ -21,6 +21,10 @@ Freedoom (various assets) - Copyright (c) 2001-2019 Contributors to the Freedoom
 Mod4Play library - 	Copyright (c) 2024-2025 dashodanger
 					Copyright (c) 2022 Olav Sørensen
 
+OpalMIDI library - Copyright (c) 2025, Dashodanger
+				   Copyright (c) 2021-2024, Devin Acker
+				   Opal Emulation released into Public Domain by Reality Productions
+
 ZDoom FName implementation - Copyright (c) 2005-2007 Randy Heit
 
 ===========================================================================================
@@ -123,8 +127,6 @@ Public Domain
 
 Fraction.hpp - Bisqwit
 
-Opal library - Reality Productions
-
 Miniaudio library - David Reid
 
 prns.h - Marc B. Reynolds

libraries/CMakeLists.txt

@@ -19,8 +19,8 @@ if (EDGE_TRACKER_SUPPORT)
   add_subdirectory(m4p)
 endif()
 add_subdirectory(miniz)
-if (EDGE_IMF_SUPPORT)
-  add_subdirectory(opal)
+if (EDGE_IMF_SUPPORT OR EDGE_OPL_SUPPORT)
+  add_subdirectory(opalmidi)
 endif()
 add_subdirectory(pl_mpeg)
 add_subdirectory(prns)

libraries/opalmidi/CMakeLists.txt

@@ -0,0 +1,17 @@
+##########################################
+# opalmidi
+##########################################
+
+set(OPALMIDI_SOURCE_FILES opal.cpp)
+
+# If only IMF is supported, we don't need the MIDI components
+if(EDGE_OPL_SUPPORT)
+  set(OPALMIDI_SOURCE_FILES ${OPALMIDI_SOURCE_FILES} opalmidi.cpp patches.cpp)
+endif()
+
+add_library(
+  opalmidi
+  ${OPALMIDI_SOURCE_FILES}
+)
+
+target_include_directories(opalmidi PUBLIC ./)

libraries/opalmidi/LICENSE.txt

@@ -0,0 +1,53 @@
+BSD 3-Clause License
+
+Copyright (c) 2025, Dashodanger
+Copyright (c) 2021-2024, Devin Acker
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+Opal emulation is derived from the RAD Tracker v2 source release, and has
+been put into the public domain by Reality Productions (see below)
+
+A quote from a letter sent by Willy Reeve to Vitaly Novichkov
+as a reply from a letter sent by Reality's (https://www.3eality.com/)
+contact form
+----------------------------------------------------------------
+All source code supplied with RAD is in the public domain.
+----------------------------------------------------------------
+
+================================================================
+The complete letter:
+================================================================
+Hi,
+
+All source code supplied with RAD is in the public domain.
+We'll clarify that in the documentation for the next release.
+
+Later...
+SHAYDE
+================================================================

libraries/opal/opal.cpp → libraries/opalmidi/opal.cpp

@@ -423,40 +423,6 @@ void Opal::Sample(int16_t *left, int16_t *right) {
     SampleAccum += OPL3SampleRate;
 }
 
-//==================================================================================================
-// Generate sample.  Every time you call this you will get two floating-point samples (one for each
-// stereo channel) which will sound correct when played back at the sample rate given when the
-// class was constructed.
-//==================================================================================================
-void Opal::SampleFloat(float *left, float *right) {
-
-    // If the destination sample rate is higher than the OPL3 sample rate, we need to skip ahead
-    while (SampleAccum >= SampleRate) {
-
-        LastOutput[0] = CurrOutput[0];
-        LastOutput[1] = CurrOutput[1];
-
-        Output(CurrOutput[0], CurrOutput[1]);
-
-        SampleAccum -= SampleRate;
-    }
-
-    // Mix with the partial accumulation
-    int32_t omblend = SampleRate - SampleAccum;
-
-#if defined _MSC_VER || (defined __SIZEOF_FLOAT__ && __SIZEOF_FLOAT__ == 4)
-    *(uint32_t *)left=0x43818000^((uint16_t)((LastOutput[0] * omblend + CurrOutput[0] * SampleAccum) / SampleRate));
-    *left -= 259.0f;
-    *(uint32_t *)right=0x43818000^((uint16_t)((LastOutput[1] * omblend + CurrOutput[1] * SampleAccum) / SampleRate));
-    *right -= 259.0f;
-#else   
-    *left = (float)((LastOutput[0] * omblend + CurrOutput[0] * SampleAccum) / SampleRate) * 0.000030517578125f;
-    *right = (float)((LastOutput[1] * omblend + CurrOutput[1] * SampleAccum) / SampleRate) * 0.000030517578125f;
-#endif
-
-    SampleAccum += OPL3SampleRate;
-}
-
 //==================================================================================================
 // Produce final output from the chip.  This is at the OPL3 sample-rate.
 //==================================================================================================

libraries/opal/opal.h → libraries/opalmidi/opal.h

@@ -203,7 +203,6 @@ class Opal
     void SetSampleRate(int sample_rate);
     void Port(uint16_t reg_num, uint8_t val);
     void Sample(int16_t *left, int16_t *right);
-    void SampleFloat(float *left, float *right);
 
   protected:
     void Init(int sample_rate);